Republic Seabee Scratchbuild [Archive] - WattFlyer RC Electric Flight Forums

Bill G

03-04-2007, 01:05 AM

This build was started at RCC (RC Cliques:D). I didn't really think there was much interest, until I checked there today, and saw a few folks were wondering what happened to the Seabee build that I discontinued there. I guess I better live up to what I said, which was that I'm moving it here.

The build started from a nice 2 view outline (first pic), posted by a builder on RCG. It had a number of the critical outlines in it, but was buy no means, a "workable plan". The line drawing was a simple JPEG on the screen, that I blew up about 500% into a fuzzy, table covering print, and went from there.

The line drawing came from another user's RCG " Build-Off contest" thread. I thanked the thread owner, Dave Blum, for using his outline, although it was put out in the pubic domain anyways. Also told him that I would not be part of the competition, since I was using his work as a start point. He had no problems with that, and found it to add interest to the thread, as I did, especially since its a seriously undermodelled plane.

Well one of their popular self-appointed mods did not think so, and sent me a nice PM informing me of my "unethical theft", and some other highly demeaning statements. For the record, I wanted out of there, and made the PM into a Thread. Hey, I thought a PM was a Public Message?:D

All forums are different. One thing I remember here, is that there is not a large "in" crowd, that is a clique who are buddies with the staff, and can abuse the power. The answer I got was expected. "Our clique can do no wrong". As I'm learning, the smaller the forum, the better. In my opinion, the difference between the "famed" modellers, and the rest of us, is "fame". That's it.
Okay, I'm done with my "Billy Bourke from Hell, siding with Foreign Dorks" intro speech.

The Seabee Build:
A bit of interesting trivia is that this plane was flown by James Bond, to Scaramang's island, in The Man With the Golden Gun. Scaramanga blew it up, while demonstrating a to James. James wasn't happy.:D
Also interesing is the Robinson Conversion, where they are installing Corvette V-8 engines in the Seabee. There is a recent replical of a Vietnam Seabee, that has gotten magazine coverage lately.
http://www.v8seabee.com/status.asp

The build started with the 2-view line drawing, and an online build, that had pics which have proved priceless. I even found video yesterday, of that online build, completed and flying off water. That build was from a 1977 RCM plan. Sheer coincidence, a photo of the build was posted in the Public Photo section of AMA's last month mag. Also coincidence that I scaled to 51" span, the same as the RCM plan. The RCM plan is not scale. The online build I've been referencing had mods done to the plan, to make it more scale. Still, the tailboom was off-scale, so thanks to Dave Blum's 2-view line drawing, I got all the correct sections for the tailboom.
http://hangaren.pointclark.net/rchangar/rcseebee.html
http://www.flyingmodels.org/showtime/SeeBee_h.htm

As a scratch build, numerous hours were spent just in developing the plan, and cutting parts, many of them being light ply. For all practical intent and purpose, I started with a 2-view drawing, that had some critical outlines, but no parts drawn into it. For the most part, my basic parts structure resembles the modifed RCM plan build, that I listed above.

At this point, I have the combined main gear and tailwheel retract mechanism working from a single GWS Micro (like HS81) servo. Both the tilt-away tail wheel, and the main gear, all work together. I plan to get a retract servo, but the mechanism removes the strain from the servo in both up and down positions. In the down position, it has a locking knee. In the up position, a progressive helper spring setup can hold it up by itself, without assist from the servo. I need an updated pic.
Flats were filed onto all of the axle shafts and the gear retract shafts also, for positive lock of the set screws, and to hold all the relative positions of the components. Some of the mechanism will not be serviceable when complete, so it better not break.:eek: The indexing flats also make it easy to dissassemble and reassemble the mechanism, without spending time to position all the parts, as this is now done by the indexing flats. The main gear pivot shaft and the gear strut legs can easily be removed and reinstalled on this design. The struts are actually made from Dubro 1/8" axles, with longer shafts made for the struts, since the included axle shafts are not long enough to be used for struts. Fot the wheels, I simply used a collar with a bolt replacing the set screw, for an axle. Aluminum tubing can be placed over the bolt, and the wheel can be drilled a few thousandths larger than the tubing size, for a smooth axle surface. These struts also have indexing flats filed on them, so that they can easily be removed and reassembled, with no time spent on positioning the parts.

The first build pic below shows about 2 or 3 revisions to the retract mechanism, before the current one:eek:, which actually works well now. The second retract pic shows where the linkage connects to the tailwheel torque rod. Still to be designed, is a steerable tailwheel mechanism that will permit the tilt-away retraction. Only some full size Seabees have a steerable tailwheel, and the ones that don't are difficult to track straight on land, with just the rudder force.

The tail feathers were considerable work. They are build using spar construction, to simulate the "ribbed" aluminum sheet, used on the full size plane, once covered with iron-on covering. I plan to simulate these ribs in the wing too.

I'm planning on the blue and white sheme (pic of full-size plane).
Normally I'm not a fan of light blues, but I like it on on this plane, and have the colors in iron-on covering also.

Bill

CHELLIE

03-04-2007, 02:51 AM

pd1

03-04-2007, 07:00 PM

Been waiting, glad I finally found this site.
Paul

Bill G

03-04-2007, 08:44 PM

Hi BILL :) that really looks like a Challange, Looking great so far, i think I would be afraid to fly it, With all the work and time that goes into a project like that, I will be following you build, take care, Chellie
I'm afraid to fly a lot of my stuff.:eek:
I usually maiden somewhere between 2 months and 2 years after a build.
Seaplanes, needing water for the real experience, provide yet another excuse.:D

PD1, I wasn't going to bother to continue posting this build, until I checked back there, and found out that there was actually interest in it. I think its better posted over here anyways. This forum here could use some new posts. Over there, if you're not part of the "expert" clique, they could care less about your posts, and in my case, even jump on you.
For some laughs PD1, why don't you copy my pics from here, and post them over there in my other Seabee thread, that I can no longer post in. I'd like to see if they bring up a "technicality" and say that it is not allowed.:D

On the Seabee, I've been experimenting with ideas for the steerable tailwheel. I fabricated the wheel caster mounting block, which attaches to the tailwheel torque rod, using a wheel collar embedded inside it to lock it to a flat spot filed on the torque rod. This part rotates about 90 deg to swing the wheel out of the water. Trying to decide how to make it steer now. So far, the easiest way seems to be a drag link driven by the water rudder, with ball sockets on either end. I wish I could use something that is more inconspicuous, but having the steering mechanism work with a retracting "swing away" tailwheel makes it more difficult.

The real "wrench thrower" is that the wheel should retract from any position in its steerable range. I have some other ideas, but I don't like the idea of having to have the rudder in the centered position, for retraction to work. There's no reason to have to make it like a nosewheel which retracts into a nosebay, where in that case, the wheel must be pointing straight ahead. I wan't to avoid that situation.

Bill

Grasshopper

03-04-2007, 09:10 PM

Bill,

Your work is always amazing to watch. Can't wait to see more pictures of your progress on this one. I also can't imagine why anyone wouldn't think you're an "Expert". You have some of the finest detail work I've seen.

pd1

03-04-2007, 11:30 PM

Bill, the full sized took care of the tailwheel off center, by spring loading the wheel ( to auto center) and the cables, to stretch a little.
If you can use something like a pull pull system, then the cables can "loosen" when the wheel assembly is rotated, with springs to keep a little tension on the cables.

Bill G

03-05-2007, 08:53 AM

Thanks Grasshopper. A lot of the "so called" rc experts hang out at that other place, in the scale forum there. Spend enough time there, and you'll get the drift. If you haven't been published, you're not part of the group. Even the contest they have now, has 2 categories, amatuer and professional. If you haven't been published, your automatically amatuer. I don't buy that, and would not enter under those terms.
Do enough building and you quickly realize that any common fool:eek: can design a balsa airplane. Converting it to a functional rc plane, with all the mechanisms, is the real challenge. Kindof like the Guillows conversions. One experienced builder recently said that he finally figured out why so many folks like Guillows conversions so much. Its because they are often NOT ideal for converting, which makes it a challenge.:D

Bill, the full sized took care of the tailwheel off center, by spring loading the wheel ( to auto center) and the cables, to stretch a little.
If you can use something like a pull pull system, then the cables can "loosen" when the wheel assembly is rotated, with springs to keep a little tension on the cables.

That's pretty much what I've come down to also. I just couldn't stomach the large drag link idea I had. Actually, what I'm thinking now is just a pull cable setup, without even needing "pull-pull", if I use a spring to force the wheel to one direction as a default.

The pull-pull would need springs to loosen when the wheel swings to retract, as you described. I still may end up doing that, but more likely with a single cable and a spring that forces the wheel to one direction, the cable springs would not be needed, since the wheel would simply turn a bit, when it swings to retract.

I still have another thought, which is a take-off of your idea. This would be to use spring wire attached to the steering shaft, to in essence make a control horn. For example, the wire could go through a hole in the shaft, and attach to the cables at the ends of the spring wire. The spring wire would be able to bend a bit, to take care of the cable length change, as the wheel swings to retract.

The one thing that I will probably do now, regardless of what variation of cable method used, is to drive the wheel from the water rudder. Using kevlar pull-pull cable, the setup will be like a "drag link". The cable/s will attach to arm/s coming off the top of the water rudder, at its hingeline. This works well, as it will steer the wheel in the correct direction along with the water rudder. I've used this "drag link" take off method before, to steer tailwheels from the rudder. Its useful where you want to mount the tailwheel a bit forward of the rudder, which can't use the simple method of inserting the steering arm into the rudder, since the steering axis is not in-line with the rudder hingeline. Pretty much the same idea here, except for that the rudder is a water rudder.

The Wheel Caster
I have the wheel caster parts made now. The main pivot block is a section of a nylon wing hold-down block. Embedded into it, is a wheel collar. The wheel collar set screw locks onto a flat spot that is filed onto the torque rod that it mounts on. The flat spot is about 1mm back from the end of the torque rod, so it can't slip off. If you look closeley at the pic, the bottom of this long set screw can be seen in the bottom of the nylon block. It seems to be working well.

The actual mounting caster is a part from an old record player. The steel that the dang thing is made of, is so hard that it will not drill easily. I drilled a hole in one side for the wheel axle, but the other side broke, when I was drilling the hole it it. What I did was to slip oval aluminum tubing over the caster arms, crimped it flat with pliers, and then drilled through the alum for the axle holes, while going through the one good hole that I managed to drill into the wheel caster arm.

Once this part is inserted into the pivot block, I will then press on a threaded linkage shaft onto the wheel caster arm, from the opposite side of the pivot block. Now I will be able to use nuts to attach whatever type of steering arm that I decide to use. For example, a servo control horn is shown in the picture.
These parts are resting on a picture of the tailwheel caster of a full-sized Seabee.

Bill

pd1

03-06-2007, 01:34 AM

Bill, If the tailwheel pivot starts to drive you nuts, you can allways make a well rear of the tailwheel and retract the wheel rearward.
I don't think anyone would ever know the difference, and it should be a lot easier.

Looking at your pictures again reminds me of the first Sea Bee I flew.
The factory gear mechanism is almost identical to yours, just the actuator was ahead of the tranverse tube, and it was under the floor.

You still came up with a system that will do the same, without a hundred engineers taking months to design.

Good going.

The Sea Bee looks great taxiing out of the water and up the ramp.
Yours should look equally as good.

Bill G

03-06-2007, 02:32 AM

Thanks PD1. I bet they did make quite a project out of the original Seabee tailwheel design. As far as I know, it was a modification after the original design.

I know one thing, that it probably did not steer worth crap by just using the air rudder, without a steerable tailwheel. I bent some caster angle on my wheel fork, but could not bend that much, as the steel that the part was made of is diamond hardness.:eek: I didn't want to break it. When I mounted it on the plane, the angle is only a degree or so, since the plane sits down so low at the rear. It eliminated most of the caster angle that I bent into it. If I push the plane, and try to use my hand to simulate side force generated by moving the air rudder, then it would probably need a football field to turn around. :D It will try to turn the caster, but slooowly. Definitely want this steerable tailwheel.

After you told me about the cable operation, I looked at the pic that I printed off of the web, and could barely see the cable on one side. Now it makes more sense. If the cables exit near the mounting shaft location, then the length change will not be that severe. I may do that, as they will be less conspicous, than if they come off of the water rudder. I could run them inside nylon pushrod sheathing, and route the sheathing up high enough in the fuse to be well above the water line, thus no leakage into the plane. My setup may turn out to be very much like the full-scale plane's.

Bill, If the tailwheel pivot starts to drive you nuts, you can allways make a well rear of the tailwheel and retract the wheel rearward.
As far as being nuts as concerned, I must be nuts for making the wheel axle the way that I did, using tiny #0-80 nuts.
It looks nice, but boy was it tedious. I used #0-80 screws, coming in from both forks, that meet in the center of the wheel, to form the axle. These screws actually have nuts on them, tightened against the inside the forks. A short piece of nylon pushrod sheating was installed over the screw threads, as I built the setup, to make a low friction axle. There is small clearance between this axle tubing and the wheel hub ID.

The way I assembled the axles was to install 1 of the 2 screws, and tighten the nut on the inside of the wheel caster fork. Then I loosely inserted the piece of nylon sheathing inside the wheel center, stretched open the fork slightly, and installed the wheel and its inner pushrod sheathing "axle bushing" onto the screw. Now I had to install the 2nd screw from the other side, get the nut inside the fork, and thread it tight.:eek: I did this by CA gluing the side of the nut onto the end of a piece of wire. Now I could get the nut into position, install the screw, and then snap off the piece of wire that was temporarily glued on. I had to perform this gluing operation several times, as the nut kept breaking off of the installation wire, as I was trying to get it into position.

All said, it was worth it, as the screw heads look nice, versus a piece of wire bent over at the ends. Too bad those little screws didn't have hex heads, as they would look really cool (scale) then. Maybe I'll have to glue fake nuts over them.

The setup is shown in the pic below. The wheel mounting pivot block is firmly attached, with its set screw tightening against a flat spot ground onto the mounting rod. The water seal can also be seen, which is a piece of fuel tubing that is stretched over the aluminum tube housing, which extends about 1/4" out of the fuse. A short length of the inner torque rod extends out of the aluminum tube housing, and the fuel tubing diameter is small enough to make a good seal against it.

For an example of a possible steering arm, 2 nuts and a servo control horn are shown. I may not use the servo horn for the steering arm, but it shows the principle. Irregardless, the arm/s will be a lot shorter. Now that I have a threaded steering shaft, I can mount pretty much anything I want onto the top of the steering arm.

BTW,
MikeF, saw you listed as a forum viewer here while I was logged on. Didn't know that you hung out here too.

Bill

pd1

03-06-2007, 01:14 PM

Bill, you're right. The full scale didn't turn worth a darn with the rudder. Most steering on the ground was with brakes.
On a delivery flight, I taxied the full length of Norfolk International, in a strong cross wind.
By the time I got to the ramp, the fire trucks were already there. They saw the smoke from the wheels. The brakes would smoke if used too much.

Make the tailwheel strong, it takes a beating going up and down ramps into and out of the water.

Bill G

03-06-2007, 03:32 PM

http://www.rcfreedom.com/Smileys/default/grin.gif http://www.rcfreedom.com/Smileys/default/shocked.gif only a hacker would figure out that you can use other smiley's here

Bill, you're right. The full scale didn't turn worth a darn with the rudder. Most steering on the ground was with brakes.
On a delivery flight, I taxied the full length of Norfolk International, in a strong cross wind.
By the time I got to the ramp, the fire trucks were already there. They saw the smoke from the wheels. The brakes would smoke if used too much.

Make the tailwheel strong, it takes a beating going up and down ramps into and out of the water.
The tailwheel assembly is definitely strong. The torque rod itself is .072" wire, and only a very short length is exposed. One good thing, is that between the wire torque rod that it mounts on, and the foam wheel, it has a lot of suspension as it is. If you drop the tail, it will bounce like a basketball for a few.:D
As for the brakes, I heard that they floored them when they could no longer keep the plane straight, and were going off the runway. :eek:

The Seabee:

Retracts
The retracts have been working for a while now, but I figured that I'd show a few pics. The first pic shows the test setup energized, with the gear down. In the second pic, I am holding the plane off the table, and the gear is retracted. If you look at the tailwheel, it is retracted by turning counter clockwise about 90 degrees on its mounting shaft. This is why the steering arm at the top is the only thing that can be seen in the left side view pic.

Steerable/Retractabe Tailwheel
I also have the tailwheel steering mechanism working well now. I need an updated pic, but the third pic below shows the principle. I have "cleaned up" the mechanism a bit, and it is now re-assembled with a pull cable. The cable exits a bit above where the mounting torque rod exits the fuse. The pull cable is inside nylon cable sheathing, and the sheathing is tied off at a high point in the fuse, before routing into the main cabin, so that it is above the water level and won't let water in. Gotta think about that stuff here.:D

To make the pull cable work, I fabricated a recoil spring, which is mounted under the steering arm at the top. Its in there, but is tough to see in the pic. One end of the spring is connected to the steering arm, and the other is locked against the tailwheel mounting block, and hooks around the torqe rod. This spring holds the wheel in a left turn, and the pull cable, attached to the steering servo in the cabin, will move in and out to activate the steering. At center postion, the spring does not require much force from the servo, so it will not overwork it. Even at full right turn, it is not very severe, as it does not require a strong spring force to hold the wheel to the default left turn position.

Tailwheel Recoil Spring
The recoil spring did take a while to fabricate. It has a bit more that 2 turns, wound from the points where it connects to the wheel mounting block and the steering arm. It took a while to get the spring rate correct, the end positions at the correct orientation relative to each other, and to make the coils neatly wound and tight together, as there is little space between the steering arm and the steering block. I could have moved the steering arm upward with another base nut, but I want the spring to be as concealed as possible.

Steering Arm
A bit of trivia is that the splined center of the steering arm, an HS81 servo control horn, fits just about perfectly on the steering shaft base nut. It would only move a degree or so, when set in place. This made it easy to get the steering spring in place and the steering arm in the correct position, before snugging it firmly with the top nut and lockwasher.

Updates, New stuff completed this evening:
The last 3 pics show the the tailwheel steering pull cable sheathing in place. It is tied off high in the fuse, before routing toward the cabin, so that it is above the water level. Looking closely, the pull string can be seen loosely threaded through the steering arm. Testing it by hand seems to work well. Also in the fourth pic below, is a small silver painted box that will slip over the torque rod and glue to the wheel pivot block, between the fuse and the tailwheel pivot block. This box was fabbed from thin plastic, and will simulate the I-beam type casting, that is part of the tailwheel pivot block on the full size plane. Note the arrow that points to the area that it will insert into, in the small detail picture of the full size plane's tailwheel.

Water Rudder
I stole my aluminum resting pad for my Monokote iron, to make the rudder from.:D I found something else to use for the Monokote iron stand.
A paper template of the rudder was first contact glued to the aluminum plane, and the reinforcing ribs were stamped into the rudder, using a hammer and a thin spatula with a strong blade. It worked well. In the last pic, the completed rudder can be seen against a full size example.

Rudder Linkage Plan
I plan to use the same pre-loaded spring setup for the water rudder, and set the spring tension so that the default postion is in the opposite direction. At the servo horn, these 2 springs would cancel each other out, when the water rudder and tailwheel are in center position. http://www.rcfreedom.com/Smileys/default/cool.gif
In this case, the opposite side of the servo horn would be used for the water rudder cable connection, and the logic would be reversed, with the rudder set to at "normally right". The servo would "let out" the cable, and the spring would move the rudder.

Bill

Bill G

03-08-2007, 07:35 AM

http://www.rcfreedom.com/Smileys/default/cool.gifhttp://www.rcfreedom.com/Smileys/default/grin.gif http://www.rcfreedom.com/Smileys/default/shocked.gif

Water Rudder

Finished the water rudder setup today. I ended up using a Sullivan Gold Cable, which is capable of driving the rudder in both directions, versus the lighter pull-only idea, with a one-directional spring. I thought about using the light pull cable used in pull-pull setups, and then ruled it out, since I don't want something that has a chance of breaking, where I can't get in there to fix it.:eek: I still mounted the spring on the rudder linkage in the fuse, so that it would cancel the force of the one-directional spring on the tailwheel, to remove the load from the rudder servo.

The first pic shows the aluminum tubing that will slide over the rudder. The tubing has a slit through most of its length, that will slide over the rudder. Two slits about 1/4" deep were cut in the top of the rudder, for the portion of the aluminum tubing that was not slit, to slide into.
The rudder steering shaft has a notch filed into it, that makes a "half-shaft" of the portion which the rudder will mount against. This part slides into the aluminum tube at the top of the rudder, and has an #0-80 screw and nut to secure it in place. It can be seen in the pic, protruding through the fuse.

The aluminum tube is secured to the rudder with thick CA, after it is slid in place. The second pic shows the gluing procedure. First, a wire was inserted to block the mounting hole, in the tab that was cut into the top of the rudder. This is done so that when the CA is injected in the fastening hole of the aluminum tubing, it will only fill on one side of the rudder. An arrow points to this hole, in the pic. The other side has to be kept open, for the "half shaft" portion of the steering shaft to slide into.

The third pic shows the mounting hole being re-drilled, since one side of the alum tube is filled with CA, and needs to have the mounting hole opened again. The last step is to inject CA into the bottom openings of the tubing, on either side of the rudder, so that the tubing does not separate from it, as the tube was slit to slide over the rudder. I also scuffed the rudder surface under the sandpaper, so that the CA would grip. Only a small amount of thick CA was used, so that it would not run toward the other end, and clog the area that needs to slide over the steering shaft mount.

In the last pic, the rudder is in place, with the mounting screw partially inserted. Not in the pic, is a servo control horn that is attached to the top of the steering shaft, used for the cable attachment.

Bill

Bill G

03-09-2007, 07:38 AM

http://www.rcfreedom.com/Smileys/default/shocked.gif

Finally just about finished with the tailwheel/water rudder area of this plane. In the first pic, the completed linkage for the water rudder can be seen. I attached a servo horn to the top of the rudder shaft, for the linkage point, which will also be used a the take-off point for the air rudder linkage, eliminating the need for another pushrod that would need to route all the way to the cabin. This also saves weight, as this plane has a tendency to get tail heavy, which is why I used a nylon Dubro linkage connector, instead of the heavier Sullivan Gold connectors, used to drive the retract linkage.

One major difference between this build, and the 1977 Model Airlane News plan build which I am referencing, is that my tailboom is scale. The existing MAN plan has a simplified boom, where the bottom hull corners are rounded, and the smooth "step" in the boom of the real airplane, at the tailwheel, is squared off. They did this for simplicity. I like the smooth blended transition of the full-scale Seabee, in this area of the boom, and also having the correct shape for the formers. I think squaring this transition really hacks this plane, since it has such nice flowing curves. It does add more work, however, to make it scale.

The most difficult part of making a scale boom is the smooth "step" transition at the tailwheel. It would be tedious http://www.rcfreedom.com/Smileys/default/shocked.gif to attempt to frame this curved area with formers and stringers and then strip plank, so I sculpted filler parts for this area, using soft, light balsa (see second pic). The sheeting will blend into these filler pieces, overlapping it at the edges of these parts.

Bill

newcomer

03-09-2007, 02:35 PM

you're a real craftsman, Bill. love to see a real builder at work.
david

pd1

03-09-2007, 03:33 PM

Bill G

03-09-2007, 05:04 PM

Bill, It's looking real good.

Have you given any thought to the spray rails?
On the two Sea Bees I flew, they were both modified with the wide spray rails, to keep water off the prop.

Also any thought of a variable pitch prop, with reverse?

The Sea Bee was the first airplane I flew that had reverse.
It was very helpfull in the water.

It also freaked a few linemen out to see the monster back up into a parking spot on land.

Newcomer, I like your work too. If you haven't recognized me, I'm the guy that's into the Luft '46 stuff like you build, at that other place.

The variable prop would be cool. A few $$ too, but cool. I guess there are some stronger ones out there, than the light duty ones that I've seen for foamies. I wonder if folks have used reversing rc car/boat variable speed controllers, and reversed the rotation? The prop is not as good that way, but will still reverse thrust.
I am adding lights though.:D Already have the tail light wired in the rudder.

If I do the spray rails, I'd probably want to build them into the structure before I sheet it, so they won't break off easily. The idea would be to have them notched to insert into the cabin, and glue off a bit inside the walls, so they can't just "snap" off the outer hull. I probably won't add them, but if I do, I'll probably do it as described. Maybe the model will not spray as much as the full size, since the surface tension and other properties of water will not be "scaled" like the model.:D

I was working on the front hull formers a bit last night. I shaped the bottoms to have a curve, like the full-scale plane. This curved front hull will help displace water when it first gets going, before the hull gets out of the water. It also looks better and more scale-like this way. I'll have to look again at the video links I posted before, and see how the water displaces with that plane. Its the same size as mine, and his hull panels are completely flat, with no curve in front.

Bill

pd1

03-09-2007, 09:10 PM

Bill, Here's a repost of exerpts from the factory manual from the other site.
Let me know if there is any other parts of the owner's manual you would like to see.

Bill G

03-10-2007, 07:04 AM

Bill, Here's a repost of exerpts from the factory manual from the other site.
Let me know if there is any other parts of the owner's manual you would like to see.
When I built the front dash support in my plane, I wasn't paying attention as much as I should have been, in the sense that it goes all the way across. I should have put it in lower. I still may mod it. I noticed that there seems to be an old version of the instrument panel, that looks different, as it goes all the way across.
http://www.stinsonflyer.com/prop/irc3-01.jpg
I may do mine that way, since it would be easier to do now. I still may go with the newer version that you showed, as I could still incorporate it into the plane, since the top of it is higher than the window line, where my support is located.

Build progress
I added the front hull section using basswood sheet. I thought about just filling the area with soft balsa and shaping, but the sheeting is actually easier in the sense that you get the right shape with little work, if its done right. I added a few strips of sqare stock wood to the hull formers, to provide a good gluing surface the the lower most portion of these sheets. This part was glued first, and then the sheets were dampened and stretched along the hull curves and CA glued in place. By having the sheets firmly glued to the former first, I was able to stretch the correct compound curves into them. They actually curve in 2 directions, along with the bottom hull profile, and are concave to displace water. Good thing that we have activator, to speed these bonds up.

Before the sheets were added, the curved frames were added, that are seen in the first pic. I've found that if you soak the 1/8" spruce square stock, you can eventually shape it like a soft pretzel. In the picture of the full-size Seabee below the model, this curved seam in the hull panels can be seen. The idea here is to get the hull as close to scale as possible. The models I've seen so far have not included all the curves to scale accuraccy. The remainder of the front area will probably be sculped from balsa.

On the scale, everything so far is 13oz, which is actually better than I thought it would be, at this point. The lightening holes do not remove as much weight as expected, but the main point was to keep the tail light, which was also one of the reasons not to sheet the tail feathers. The tail lightening is important, since every gram of excess tailweight requires about 2 grams in the nose, to maintain the CG setting.

Bill

pd1

03-10-2007, 01:33 PM

Bill G

03-11-2007, 09:07 AM

Bill, The picture on the link you have is not a Sea Bee.

It's either a Spencer Aircar, or an Italian Riviera.
http://www.pilotfriend.com/experimental/acft6/37.htm

The Sea Bee landing gear rotated rearward, there was no well for the gear.
The picture shows a wheel well.
Also the Sea Bee had the wing strut ahead of the gear. There is no strut in that picture, I vote it's a Riviera.
http://www.aeromods.com/riviera/

Also, the Sea Bee had a third door in the front for docking, if the panel went across as depicted, you couldn't use the door.

You build looks good, and I bet the lightening holes pay off dividens, it's easier to remove one gram of weight from one hundred parts than one hundred grams from one part.

Paul
Guess I didn't look that closely.:eek: I looked at the link for a second or 2, and then saved it. I guess I'll be modelling the standard instrument panel then.:D Should still look pretty good, as the top portion with the rounded corners will rise above my existing dash support, and the front of it will be much larger than the small cross tie that goes across the cabin in the same location. I could take out my dash reinforcements and move them down, but I prefer to keep them where they are.

On the lightening, I'm starting a new principle of removing weight from most ALL parts that I can. I may be minor, but weight is weight, and it all adds up. I heard about a redesign of one of the Mazda 262 prototypes around 1990. To lighten the car, the project manager specified a 10% weight reduction of all the parts. Realistically, I'm sure it wasn't every part, but the idea still stands. Keep every part as light as possible. Remember, it has to defy gravity.:eek:

Seabee Tailboom Trussing and Stringing
Most of the tail boom stringers are in place now. Looking carfully at the pic, trusswork can be seen also. The trusswork basically makes it like a bridge, in design. Fuse formers offer little strength longitudinally. One poor solution would be to make the formers out of heavy ply. A much more efficient soulution is to add lightweight trusswork. Another benefit is that stress concentrations can be relocated. Notice the longer truss braces at the beginning of the boom, coming off of the cabin. They tie in to the center keel aft of the point where the boom connects to the fuse. This disributes the stress concentration at the cabin-boom joint, where the stresses are the highest and it is most likely to break.
To get an idea of the potential strength added by trussing, look at the MIT students that put incredible loads on model bridges made of balsa. :eek:

The plane will be sheeted with 1/32" sheeting, which was one of the first decisions made on this plane. Using 1/16" sheeting would make it a tank! http://www.rcfreedom.com/Smileys/default/shocked.gif I'd rather add a few more stringers to support the thinner sheeting and still come out lighter, than to get away with adding fewer stringers by using thicker sheeting. 1/32" sheeting is a lot easier to work with also. I'm not a strip planker. I like working with larger sheets, and am a big fan of sheeting. I sheet everything. It adds challenge to building micro flyers too.http://www.rcfreedom.com/Smileys/default/grin.gif I've already worked out most of the sheeting scheme. Shouldn't be too bad.

Hitting the CG looks right on target at this point, now that I have most of the tail boom weight in place so that I can check it. I taped the tail feathers in place and put a TP 3s-2100PL in front, and I am actually about 2" in front of where the CG needs to be. When the motor is installed later, toward the rear of the wing, it should then be close. While I realize that the CG can still change a bit as the build progresses, I'm at the point now where I believe that I will not need much ballast, if any, to mount the motor on the rear half of the wing. I want to avoid using a driveshaft, so that the motor can be mounted on the front of the wing, but will still do so, if it saves from needing substantial nose ballast.

Bill

pd1

03-11-2007, 02:52 PM

Bill, The Riviera is a nice looking plane, eh?

Looking at your structure so far,I think your Sea Bee will be plenty strong.

Are you planning to give the structure a coat of sealant of some kind, before sheeting?
I used to fly a lot of models off water, the planes would magically gain weight as the day progressed.

Covering with 1/32 sheet, my hats off to you.
I can't work with that thin stuff anymore.
I've had a lot of nerve damage in my hands, and now I'm always breaking pieces off my planes before they are finished, and that's with the heavy stuff.

Why does it seem on this forum that so few people actually leave comments?
I think a lot of people are reading these threads, but they just don't ask or comment.
Just wondering why, this plane is so different that I thought people would be flooding you with questions.

Grasshopper

03-11-2007, 05:11 PM

Bill, The Riviera is a nice looking plane, eh?

Looking at your structure so far,I think your Sea Bee will be plenty strong.

Are you planning to give the structure a coat of sealant of some kind, before sheeting?
I used to fly a lot of models off water, the planes would magically gain weight as the day progressed.

Covering with 1/32 sheet, my hats off to you.
I can't work with that thin stuff anymore.
I've had a lot of nerve damage in my hands, and now I'm always breaking pieces off my planes before they are finished, and that's with the heavy stuff.

Why does it seem on this forum that so few people actually leave comments?I think a lot of people are reading these threads, but they just don't ask or comment.
Just wondering why, this plane is so different that I thought people would be flooding you with questions.

I'm sure watching it! I'm amazed at the talent and skill level on this. I can't wait to see it fly. Bill, you can't wait two years to maiden it though. :D

pd1

03-11-2007, 06:06 PM

Hi Tom, he's doing a fantastic job on a very unusual and difficult plane.

The build has so many departures from normal planes that I was just wondering why there has been so few questions.
I know I have a million questions on this build, and I'm seeing more as he works.
I just feel guilty asking all the questions.

Maine Flyer

03-11-2007, 10:45 PM

Watching also. No questions at this time but I do echo those comments regarding some kind of internal waterproofing. I lost a water rudder on a Seamaster last year due to covering coming loose and becoming water soaked.

Presently I am building a Cessna 195 kit (will have floats) and waterproofed all internal parts I could.

What this thread teaches - I hope - is how light you can build a strong structure. Something I am still learning as I tend to make parts stronger than necessary.
Joe

Bill G

03-12-2007, 05:45 PM

Grasshopper, I will want to fly this plane sooner than that, but the problem is that it may take 2 years to finish.:D A lot of details on this plane that I'm not use to doing on the standard issue warbirds. Construction is just a little different too.:eek:

I was just staring at a can of Balsaloc last night, and wondering if it is a waterproofer. I definitely want some type of waterproofing on at least the lower hull wood. Considering that I actually use water to soak hardwood stringers and basswood and ply sheeting so that it can be formed like a soft pretzel, I think it would be a good thing to waterproof them.:eek:

What are folks using for waterproofing wood?
Can sheeting still be glued to the wood afterwards?

Joe, I really could use some better pics, but the trussed boom structure is probably the best example of using lightweight bracing. A structure like this can be trussed, like bridge construction. To gain the same strength without them, the boom formers would have to be made from much heavier wood. I tend to make stuff much stronger than necessary too. What I'm trying to get away from, is to make one section of a part stronger than needed, while another section is still the weakpoint. In other words, inefficient.

I also thought about the potential of losing parts. My tailwheel assembly is spring loaded with a pull cable looped through the steering arm. I ain't losin' that part! Way too many hours into the little sucker for that to happen. The water rudder has a small set bolt, not screw, but bolt going through it, and the top of the steering shaft is permanently welded (mrg part) to the shaft. Same goes for that part, I'd cry if I lost it.:D

Another thing I started paying attention to here, is reinforcing long stringers. Nothing is worse than breaking one, after your plane is sheeted and finished. If you look at how they fail, its usually in the center, especially when the plane is handled, and a spot is gripped too hard. The wood fails when the far side of the center exceeds the tension and bending limit of the wood, and does not fail in shear. Balsa is not good in tension, in the cross grain direction. What's not as obvious, is that is you can stiffen the stringer to STOP it from bending, then it will not fail nearly as soon. I've found that if you laminate a second stringer of only about 1/3 the length of the stringer section, in the center and on the inside, that the strength gain is substantial. Laminating a full length stringer to an existing stringer is just dead weight, since the section that usually fails is the inner face of the very center, which fails in tension and bending. Another thing I found is that it is the lamination layer of the CA that really provides much of this added tensile strength, just like in the resin engineered beams. The reinforcer added to the center of a stringer does not need to be as thick as the original stringer, for a large gain in strength.

While that may seem like quite a dissertation on adding a small reinforcement patch and a point load in the center of a beam:D, its something I will probably be looking at in the future. Using the idea, a plane could be built with fewer formers and longer spans of stringers in between. The weight of the short splices added to the stringers is less that the reduced former count, and the strength gain is considerable.

New progress is the elevator servo and pushrod are in place. I made an adapter mount for the elevator servo, so that I can remove it and install a larger servo if I choose to, as a drop in replacement.
Bill

Maine Flyer

03-12-2007, 06:16 PM

Bill, I use epoxy thinned with alcohol. It added about 1/2 oz to the fuse when I build my Drake II. AUW ended up at just about 40 ozs. It gave me some piece of mind if I got some water into areas where I didn't notice it.

I'm sure there as many solutions to waterproofing as there are flyers on this forum! A friend of mine had to redo the hull of a Seamaster due to water inside. He ended up with mold in some areas.

Keep up the good work!
Joe

pd1

03-12-2007, 07:05 PM

Bill, I agree with Maine Flyer. Thinned epoxy works good.
I used to thin it with lacquer thinner, alcohol might work better though.

Maybe even spraying the uncovered structure with rattle can clear?
Anything should be a help.

E-Challenged

03-12-2007, 07:06 PM

Bill, glad to see you doing so well on the Seabee, hope to see successful flight shots. I wish my own abilites were as advanced as yours.
I wouldn't trust Balsa Loc to be waterproof. Sig Stiksit or Balsarite would probably work better. BTW, I concieved the idea for the "fun build off "contest" on E-Zone including the amateur and pro categories to bring the range of scratch designer/builders into the competition who might otherwise not give it a try. I have never met Pat Tritle or Charlie Manzano, etc. but admire and respect what they do. As to the "powers that be" on E-Zone, I don't know them at all and have no reason to suspect any "conspiracy theories". I appreciate the efforts of all who keep all of these online modelling forums going an am glad to contribute what little I can.

Bill G

03-13-2007, 09:04 PM

Thanks for the comments. I'll have to try the thinned epoxy. Probably adds a good bit of strength too.

EC,
As for conspiracy theory, the only conspiracy, if that, is that people like Martin who do reviews there, have preference with the staff. Its obvious and normal, as theirs this thing we call "buddies" in the world. Still doesn't fly with me, that they are automatically right, and can send insulting PMs to folks they don't know, about things that don't concern them. As far as I'm concerned with that place, when they lift the temp, I'll go back there and defend the false statements he made AFTER I was gone, and they can hit their little magic buttons again if they wish. As for the powers that be there, I didn't want to know them either, but I sure do now.

Bill

Bill G

03-14-2007, 06:18 AM

PD1 or Maine, what type of alcohol do you use?
Also thought about polyurethane. Not sure how well it works to waterproof balsa, but is light. I may glass the bottom areas up to the waterline also.

Seabee
Carved pieces to sculpt the nose section from. In the first pic, they are not glued in place, and only test fit into place. Was a bit of work making all the parts fit that well. The pieces were made from the same 3/8" x 1" balsa stock, shown in the foreground of the pic. I started playing around with ideas, and arrived on a scheme of parts using that stock size, that fit together as if it was meant to be. I plan to carve out some weight from the rear of them, but leave enough thickness for good strength.

In the second pic, the parts are shown in an "exploded" view on the left, and are fit together on the right. The center part, which is set up on an eraser, is the front most part. Additional balsa was glued to this part, to add material to its front face. This part is stacked on top of the part to the right, when assembled. A section of tri-stock was added to the right most part, which provides more material for the seam area, since the area will get thinner once the final sculpting is done. The left most part is the side piece, which glues against the other 2 parts. The parts were pre-sculped to get the nose shape close, before permanently gluing into place.
The other thing in this pic is my antique wooden "H" puzzle. This nose assembly reminded me of it, since just like the H puzzle, it took a good while to figure out how to make it. When I was a kid, I spent hours with the dumb puzzle, and couldn't get the perfect H. Got some lousy looking ones, but dad said that they didn't count.:D

Did a bit of sheeting in the third pic, since I had to see what some of it would look like with the sheeting. The small patch with blue iron on covering was applied to the tailwheel area after waterproofing the wood underneath, so that I could complete the tailwheel pull cable linkage. The plane will be done in a scheme with this color and white. Normally don't like baby blue, but this scheme looked good, and just as important when you're broke, I have the color.

Bill

Maine Flyer

03-14-2007, 11:52 PM

Bill G

03-16-2007, 02:30 AM

Bill,
I use Isopropyl Alcohol 91%. Less water in it. 99% would be better if you can get it. I feel it does help strengthen the assembly and I am a bit liberal about applying it!

I have heard that polyurethane works well also. Some use it on glass.

I did glass (with 3/4 oz) the entire hull of my Drake II but found it made it a bit harder for me to cover without bubbles. But if the covering "leaks", the hull is protected by the glass. Works for me!

Joe
That's what I thought. Good thing, as everyone has a bottle of isopropyl they can swipe from the medicine compartment.:D Don't want to buy something special if I don't have to. My LHS owner likes Sig clear dope. The toss up is that epoxy takes effort to mix, but then the dope has to air dry and stinks like hell, and I like things the harden quickly, like 30 min epoxy. I use way to much activator on CA. Harden now!:eek: 30 seconds, to a minute, is far to long to wait.

I've heard of all the WBPU used on glass. This is probably the only case, for waterproofing, that I would glass. I'm a big iron-on fan. Good point about the bubbles, since you can't force trapped air through the balsa as easily.

Got a few more pic I'll have to post later to, after taking Fox out for a walk.

Bill

John Seidelman

03-16-2007, 03:10 AM

MikeF

03-16-2007, 04:52 AM

Hi Bill.
Remember me.:) :eek: :)

FWIW Denatured Alcohol solvent from the local hardware store is a better choice for thinning epoxy than isopropyl.

Good luck with your build.
Mike

Bill G

03-16-2007, 07:25 PM

Installed and sculpted the nose section. The first pic shows a front and rear view of the assembled parts. I hogged out the rear of these nose parts to save weight, as it looks like I will not need added nose weight to set the CG, and will probably not need to mount the batt all the way forward either.
Scupted to shape in the second pic.

On the "bubbles" thing, we were referring to trapped air underneath iron-on coverings, since the poly coated balsa can no longer pass air through it. I will make sure not to torch any table tops, though.:eek: :D

Hi Bill.
Remember me.:) :eek: :)

FWIW Denatured Alcohol solvent from the local hardware store is a better choice for thinning epoxy than isopropyl.

Good luck with your build.
Mike

Guess you missed this from my previous post:
Quote from post #9:
http://www.wattflyer.com/forums/showpost.php?p=164227&postcount=9
BTW,
MikeF, saw you listed as a forum viewer here while I was logged on. Didn't know that you hung out here too.

Maybe you can do me a favor? Tell the folks there about the real reason for the Temp B. I got over there.
I saw MH posting over there, telling false stories as to why it happened. The real reason I got the time off over there, was for posting his picture in my avatar.:D LOL
I had it saying "professional dork", it dissappeared, so I figured maybe something went wrong, I then reloaded it, and before I could get back to the posts, I saw the the little TB note, and the avatar was gone again. They had put a "watch actions" on my account.

Bill

pd1

03-16-2007, 08:52 PM

Hi Bill, Maybe useing denatured alcohol works better than lacquer thinner.

It was a long time ago, I had the thinner, so I just went with it.

I thinned the epoxy so it was like water. I just wanted to fill the pores in the balsa, not fill the grain. I didn't have any bubbles with the covering after that.

I think I saw an add for Ultracote where they claim it didn't bubble over other coverings. That might be another solution.

Build looks better and better.
Paul

MikeF

03-17-2007, 03:06 AM

Bill G

03-17-2007, 08:18 AM

Yup, I guess I missed that you saw me here. I pop over every few days to check out whats going on. Been following your build but mostly skimming and looking at pics. Actually been spending a great deal of time at the Flying Giants site as well. Between the 3 forums I'm not getting any friggin work done at all.:rolleyes:

As for the "other site" I figure it's best to let it go. I missed the MH avatar trick. Kind of funny, but you had to know that would get you in trouble.:rolleyes:

On all the forums I figure it's best to have a thick skin and try to keep a cool head. Can't let your own self worth be dictated by a bunch of people you don't really even know. Personally I'm just trying to hang a low profile and not stir things up.

Look what one poorly thought out sentence did for you and me!:p

Keep up the good work. I'll be watching.:)

Mike

Thanks for the compliments Mike. Also, that's why I like to add pics. I occasionally read things, after looking at the pics, if they're are any in the first place.:D

Been adding the last few stringers, and like any scratch build made without plans, I've been sanding and padding out a few areas, to tweak the shape. Pretty much ready to sheet the plane now. I waterproofed all of the lower framework, and the inside of the tailboom hull bottom. I will add the front hull bottom next and waterfroof it, before finishing the remainder of the sheeting.

The other place:
What amazed me is that it took 5 seconds! They were watching. I mean really watching!:eek: They sure knew it was him, and there were only 2 pics of him on the entire site. What got me in trouble was the he is buddys with the staff there. That's why he has no qualms about sending anybody a nasty PM, even when he doesn't know them. I agree that you have to keep a cool head and lay low. This case was different, since I knew that the guy could get away with murder there. Either way, he got the exposure for it that he deserved. I knew who his friends were, and don't get intimidated by it. What's not worth it, is to put up with that crap, and keep quiet.

They left the profile statement that I put with it, since it looks funny and bad on me, without the avatar. Not cool. Well, when I get back there, the avatar's going back up. Look for it an about 2 months.:D

Bill

Jim Casey

03-17-2007, 03:21 PM

Bill G

03-17-2007, 03:54 PM

Maybe I'm too late, but for waterproofing I like to use brush-on water-based polyurethane varnish. I use it to stick down my glass cloth, too. It is possibly not as strong as epoxy, but vastly more convenient, less expensive, and doesn't stink. I fly slimers, too, and it is fuel-proof. Film coverings bond well to it.

I found a can of clear poly, and have been using it. I doped the first coat, and then added the poly for the second coat, once I found the can. I still can get in there to coat the hull bottoms. Haven't put the sides on yet, since I plan to add a good few coats.

Bill

Bill G

03-18-2007, 08:17 AM

:eek:

I've got the nose just about the way it should look, with a few coats of sanded primer, and some filler. Been using this DHP filler that the LHS just got in, which seems to work better than the Hobbico that I had been using, and the Goldberg filler.

Painted the steerable/retractable tailwheel assembly with aluminum paint. Looks fairly close to scale, although the fork angle is too straight, and it doesn't have the mechanisms above the main body casting, that the real one has. Still has functional axle bolts (#0-80 screws) like the full size plane, a top jam nut on the steering spindle, and a simulated adjuster on the top rear, like the full size plane. Still much better than just a piece of wire and a wheel.

Finished the main cabin hull bottom sheeting, and waterproofing the inside surface. I made sure to coat everything from the cabin floor and below, all of the fuse and tailboom formers, and the main center keel. This plane should be able to take a mild soaking, without exploding.:eek: I remember how a Dumas boat that I build years ago had leaked and swelled, even after I had thought it was sealed on the outside, with paint. Gotta coat the inside surfaces too. The cabin sidewall sheeting will be coated once installed also. Pretty much every inch of the structure will be coated, by completion. You don't usually get this with an ARF. I will have to coat the tailboom sheeting inner surface, before applying the sheeting, since the area will be inaccessible afterwards.

The front hull is actually curved in like a displacement hull, although it can't be seen well in the third pic. A small portion of this feature can be seen in the first pic, in front of the masking paper. This will not only make the hull look scale, but hopefully will also displace water better than a flat pan hull.

Bill

Bill G

03-19-2007, 08:05 AM

:eek:

Look what I found buried in the house! Thin white cardboard covers for my building board. Anyone who's seen my threads, knows that beat to crap building board right away.:D I even found three of these covers. The make the pics look better, and not small parts will not be camoflauged into the board surface.

Added the window frames today. The "glass" will install from the inside. I'll need to make a mold for the front window, to put a bit of curve into the clear plastic sheet. The cabin sheeting will overlap the side windows, all the way to the front window pillar. This will make the outer surface coincident with the the cabin sides, and the added balsa thickness will provide a bit of latitude to sand the curve that begins at the top of the window frames, which will blend into the roof. The window frames and fillets were made using basswood, light ply, and hard balsa. The idea here is to have a harder material than the outer layer of balsa sheeting that will be applied and cut out, so that it will provide a stiff guide to cut the windows out of the sheeting, and will also strengthen the frames.

The more these details are tackled one at a time, the more I realize why this plane is rarely built, and when built, not often highly detailed.:eek: One good thing, is that there is never a shortage of different tasks that can be done. If your not in the mood to to one thing, there's plenty of other things that can be done, and many of the tasks do not need to be done in a specific order. This build is really like building several planes, or at least several major projects, broken into the cabin - detailed interior, tailboom - tail feathers, retracts, wing assembly with floats, and removable roof and "engine" cover.

For motivation, I look at these videos of an rc Seabee from time to time, the same size as this plane, built from modified RCM plans:
http://www.flyingmodels.org/showtime/SeeBee_h.htm

The main balsa sheets for the tailboom have also been cut out, and waterproofed inside. They will cover the sides of the boom, up to the the stringer where the boom curves steeply over to the top surface. This remaining top area will be sheeted with individual panels for each section between the formers, like the real plane. The boom angle changes between the last several formers, at each former, requiring the use of separate sheets.

I also ran the wire for the rudder tail light. Gotta do that before the boom is sheeted.:eek: I have the wire end sticking out of an opening in the boom where the front frame of the vertical stab will glue into, and a string tethered to it, which routes out of the exit hole in the rear of the boom. This way, I'll be able to pull the tail light wire through the boom with this string, and then solder it to the existing wire that exits through the front v-stab frame mounting opening.

Next pics should show the tailboom sheeted.

Bill

Bill G

03-21-2007, 05:10 AM

I was ready to start sheeting, and I slowed myself down, to add needed insets to support the sheeting, and sanded and padded out some areas on the boom, to get the shape correct. Usually I get in a big rush at this stage, but it will pay off later on. From a top view, the boom sides are straight. My boom had a slight curve going inward at the beginning of it, and the rear area had some contours that were a bit off. They are now corrected, and I won't have to look at it later, with afterthoughts. A build with hand drawn plans and hand cut parts does not quite go together like a CAD drawn laser cut kit.:eek:

In the first pic, some insets were added to the front seam where the sheeting will butt against the nose block, for support. The second pic shows the ply insets for the wing strut attacment clevises, which are easier to install now, than later. I think I finally have everything ready, and the sheeting is pre-cut and waterproofed, ready to go on.

Bill

Bill G

03-22-2007, 12:58 AM

Sheeted the main cabin. Turned out pretty well, and since the pic it has been filled and sanded smooth. I used reinforcement strips inside the cabin to push out a few low spots, which are ran across the sheeting grain direction. They stiffened the areas so well, that I filled all the areas between the formers and stringers with these stiffeners. The plane is being sheeted with a thick grade of 1/32" balsa, which is still a good bit lighter than 1/16" sheeting. Later, the cabin interior walls will be sheeted with very light 1/32" sheeting, and a scale interior added.

At this point, I can pretty well estimate an AUW of 45oz, with a 51" wing span. This will give a wing loading of about 18oz/sq-ft, which is high enough as it is. This is the main reason for the 1/32 sheeting.

Bill

Bill G

03-22-2007, 09:35 AM

http://www.rcfreedom.com/Smileys/default/shocked.gif
Mostly finished with sheeting now. Since the pics, I've added the right side sheeting of the boom, and have the top section of the boom to complete. In the pic, the lower rear of the tailboom sheeting had not been glued yet. It is now, as it was a secondary operation, where a relief cut was needed at the rounded step in the boom, where the tailwheel is located. It was then dampened and curled under the bottom, and glued in place. The top of the boom will be sheeted in 3 sections, like the full size plane, since there are 2 points where the contour changes. The sheeting was a procedure, since its difficult to do it all in one gluing session. The more time taken to determine your procedures large panel sheeting schemes, the better.

I also decided that the front cabin structure was strong enough to cut away the passenger side of the dash, back to the first cross support. This area is supposed to be open, for passengers to exit through the docking door. The other side is where the dash and instrument panel are located. The dash had 2 cross supports originally, so if removed 1/4 of the dash, going back to the first support, to make the interior look more scale. To add strength, I added another front cabin cross support at the level where the false floor will be mounted. On the real Seabee, the right front cabin area is open all the way to the nose, for ease of exit through the docking door on the passenger side, but I'm not going to eliminate the entire dash :eek:, since I want the cross support that is still there.

I'm really glad that I added numerous extra sheeting support splints that run from stringer to stringer, in each bay between the formers in the tailboom, in essence adding extra formers for the sheeting by making a perimeter support. They were added since the last pics posted. Since this heavy 1/32" sheeting is not exactly as stiff as 1/16", the support was good. I did not press the sheeting in hard, to contact every spot, since I was more concerned with a wave free smooth contour. What I did afterwards, is drop bomb:D thick CA onto these splints, and other spots where there was no contact, to fill the voids. Without these added splints, I would have had a very springy sheeting job, but it is quite stiff now, since it has many supports points. I don't do everything exactly 100% orthodox, since I'm more concerned with the final result, than having my build published as master modelling quality bare bones work.:eek:
(I've never seen the thick CA drop bomb fill method described in mags)

Bill

pd1

03-22-2007, 02:41 PM

Bill G

03-22-2007, 05:04 PM

Bill, it keeps getting better.
Because I'm too cheap to buy the thick CA I tried this.
Use baking soda as a filler, then drop a few drops of CA on it. It fills voids, and acts as an accerator for the CA.
Just don't have your eyes too close, it kicks off and smokes, the smoke irritates the eyes. Don't ask me how I know.

I put baking soda in a squeeze bulb and I use it just as an accelerator as well.
Thanks for the comments PD1.
BTW,
I once got the bright idea of mixing a bit of plaster with CA on a piece of cardboard, to fix a chip in porcelain. I did not know that it (I think the lime in the plaster) was an accelerator. The plan was to mix it with my finger and apply it. It started smoking on my finger!:eek:

Here's a more recent pic of the sheeting. The tailboom sheeting went well. A small balsa patch which needs to be sanded, barely seen at the top of the beginning of the boom where it blends into the cabin, is the only spot I had to pad out a bit with balsa to fill a low spot. The boom sides sheeted so well that I only had to sand a small amount of balsa thickness to remove any waves. They were certainly more work to sheet than the cabin, but actually required less sanding than the cabin to straigten, and no filler as of yet. Sheeting around an area with continuous curves actually keeps the balsa from getting dimples and high spots, since the curves add strength to the sheeting.

Bill

Grasshopper

03-22-2007, 05:28 PM

That's looking great Bill! A 2:35 AM Post? You need to get some sleep so you don't pass out in a blob of CA. I would hate to see the next picture of it glued to your forehead.

pd1

03-22-2007, 05:33 PM

Tom, that's a terrible thing to say.
Imagine how much that would hurt, having to cut his forehead away to save the plane.

But it would look funny though.
Probably get printed in the tabloids too , "man has giant airplane growing out of head".

Grasshopper

03-22-2007, 05:35 PM

Maybe we could all chip in and buy a snorkel and a tub of CA Debonder. :D

Bill G

03-23-2007, 02:08 AM

:eek:
Go look at my post times, and you'll get a real kick. :D
My life story lately: Got a couple hours?:eek:

Bill

Bill G

03-23-2007, 08:13 PM

Finished levelling the sheeting on the boom, and shaping the curve in the rear boom area. Still have the top boom area to finish. Also shown is a poor pic of the blends where the boom meets the fuse. These actually were less difficult to fill and shape than I expected, and needed only a small wedege of sheeting to fill the void left where the sheeting was slit. Good thing that I backed this area with balsa first, before sheeting.

The thing's starting to look like an airplane, but still have a long way to go.:eek: Haven't even started on the foam core wing and more difficult curved parts like the removable roof and engine cover. Still, I'm finally starting to feel like I'm getting somewhere with this project.

Bill

flypaper 2

03-24-2007, 02:48 PM

Bill:
If you want paint that looks like real aluminum instead of painted aluminum, try the Testors chrome paint in the spray bombs. I do my GWS orange props with it and people ask where I got the aluminum props from. Also, throw a small piece of real sponge in the bottom of the fuse and it will soak up any water sloshing around.

hakanf

03-24-2007, 02:52 PM

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newcomer

03-25-2007, 12:06 AM

Bill,
no matter what forum you're using, i Always enjoy (and learn from) your threads.
david

Bill G

03-26-2007, 01:51 PM

Thanks for the comments guys.
Newcomer, any new Luft builds? Always like to see your work too.

Never used Testors chrome paint. The tailwheel has Testors alum paint, but is so small that irregularities are hard to see. I've found that mixing it well, and applying in straight strokes can give a good "brushed aluminum" effect. For cast aluminum parts, the spray would be more realistic.

As for a sponge, the bottom has so many individual bays, it would not be practical. What I have done is to add so many coats of waterproofing to make sure that I didn't miss anything, that I'm convinced that I could use it as a fish tank if I wanted to.:eek: Just have to seal the windows pretty well, that's all. I would want to seal them, since its where you would look in and see the fish.:D

Seabee Progress
I have the last piece of boom sheeting cut out and ready to apply at this point. I've kept the dope and Balsarite on the front of the workbench, so I don't forget to brush the inside of the panels before gluing them on. Of all my builds so far, I've put more effort into tweaking perfectly fitting panel seams, than any in the past. Takes a while to get them to fit like a glove.

In the pic, is also a hand drawing of the engine cover, since the 2-view I used did not have it. I'm looking forward to starting on it and the wing, since I've been on this fuse forever. After a number of fill and sand operations and a few sanded coats of primer, the fuse should be pretty straight now. Balsa sheeting does not lend well to levelling, since the glue seams are so much harder than the rest of the sheeting, and the filler is never exactly like the surrounding balsa. You pretty much have to give it a consistent base of primer, or some other sealer, from time to time as you go through the fill and sand process. Otherwise, every time you fill and sand to straighten an area, any area next to it that has already been sanded to perfection gets ruined in the process.

I may have stated this before in the thread, but this DHP filler I've been using seems better than the Hobbico or Goldberg that I've used in the past. Good stuff.

Bill

pd1

03-26-2007, 03:09 PM

Bill, are you going with the stock airfoil?

Bill G

03-27-2007, 07:23 AM

Bill, are you going with the stock airfoil?
Pretty much. The foam core I am using is from a FlyZone Cub. I'll have to add the Horner tips onto the ends, which will extend the span to 51", but otherwise its the correct size and shape, and basically a Clark-Y.

I finished the last sheeting section today, and also added the fillets to the front window frame corners, and small ledges to the bottom of the frames, to retain the glass which will be installed from the inside. I also realized that I had not yet added these ledges to the bottom of the side windows, so that was done also, and they were blended into the bottom fillets. Details galore on this plane.:eek:

Bill

pd1

03-27-2007, 01:50 PM

Bill G

03-27-2007, 05:04 PM

Bill, the glass on the full sized was held in place by a rubber gasket,like old cars did.
If you let the student drop the plane onto the water from 10 feet, the windshielp pops out. Don't ask.

I flew two Sea Bees, one had the stock rounded wingtips, the other had the tips removed and flat tip plates added.

The one with the tip plates had a much better roll rate. Go figure.

I've seen pics of the window detail, which looks similar to how car windows are installed. From reading about the plane, it was engineering with automotive assembly techniques. I guess the cabin must flex enough to let the gasket pop off of the flange, with a hard landing. I thought about painting the window perimeter black, to simulate the rubber gasket. Definitely too small for a sane person:D to attempt to build it with a real gasket, at this size.:eek: Thought about that idea too, for a second.

In the first pic, believe it or not, the side windows are temporarily installed after a few hours:eek: of trimming each one for a perfect fit. I thought a reflection would be seen in the pic, but they really are in there. They fit the entire frame area from the inside, which is considerably larger than the window cutouts. This will give a good area for gluing, without making a glue mess of the area in the window cutout. The only delicate operation will be gluing in the bottom, where the window retaining ledges are about 1/32" high. I'll need to run a small bead of glue along that area. The front windows will be heat formed to shape over a mold, since a flat sheet will not fit well or look correct.

The instrument panel and cover are now completed as an assembly. It fits neatly into place without glue, although I probably will glue it in permanently, at a later time. Its a slight comprimise between my original plan, and the full size instrument panel, since my T-beam window pillars are thicker than those on the full size plane. On the full size plane, the instrument panel cover runs flush along the inside of the window pillar and inner door panel. My door panels will also be thicker than the full size plane's, considering scale.

Bill

pd1

03-27-2007, 05:37 PM

Bill G

03-28-2007, 06:49 AM

The new instrument panel looks real nice.

The original full sized instruments look like the came put of a 49 Hudson though, very art deco.

Are you going to try to make the panel look chrome-ish?
Or are you going to make the panel look modern.

The tachometer was useless, there was this really long cable from the panel to the engine, at least 10 feet long.
Who would have thought that it would cause the tach needle to shake when it needed lubrication?

But it looked pretty.

I thought about using aluminized duct tape for the instrument panel. I have the dash assembly painted Panzer grey now, but I still may use the aluminum tape. Since I'm replicating a real plane, I may use what it has. I know the dash on it is a dark grey flat color. I cut out some Jtec instruments for the panel, since I can't find one to print, without the steering wheel (whatever they call that thing:eek:) in the way. This is pretty much the last panel that I'll make out of the Jtec set, since its pretty well pirated now. I heard you say that the instruments were a bit old fashioned, but I still decided against using the WWI instruments that are still on the Jtec label set.:eek:

I looked at that website again where I saw an old style dash, that I decided against using. It actually is a Seabee dash, according to the site, but its from a prototype version. It looked real old fashioned, like from a Model-T.

I guess they would have geared down the tach cable, but at 10' anything would bind-release-bind-release....
I imagine many have replaced it with an electronic tach with an inductive pickup coil.

Started sculpting the engine cover mold out of foam, since I decided to go with glass. At this point, its further along than in the pic, and has a coat of filler on it, ready to be sanded. For this mold, I'll wrap it real good with saran wrap, so I can use it again. I molded a Hellcat cowl that turned out great, since the resin fortunately set up before it ate the mold:eek:. The mold for that cowl is shot.:D

Bill

pd1

03-28-2007, 01:56 PM

Bill G

03-28-2007, 06:31 PM

Bill. the ,"steering wheel," is actually called a," control yoke".

The full sized had a fan up in the front of the cowl, to force outside air back over the engine.

The first Sea Bee I flew I ended up delivering it to Florida. I got the job because the owner couldn't wait until the plane was finished being repaired. He was planning to fly it to Florida himself.

While he was flying it with the mechanic that just completed some work on it, the fan assembly froze and broke.

The fan shot fan blades down through the cabin like shrapnel. No one got injured, but he decided he would like someone else to fly the plane about 25 hours and work the bugs out, before it went to Florida.

I think what really made up his mind for him was on that landing, the gear collapsed as well.
No damage, the plane slid along the runway and didn't hurt the pavement at all.

On the plus side, I got a job, and an adventure. The Sea Bee always had a few more tricks up it's sleeve.
That term makes less sense than a "steering wheel".:D

I imagine the fan is only needed at low speeds, such as when "boating" in the water? I guess the blades must spin with a good few rpm?:eek: Maybe the plane could use a thick plate for a "scattershield" bellhousing, like manual transmission drag cars.

Was the gear not "locked" down. From what I see, the mechanism takes advantage of a "locking knee" effect in both up and down positions, with 2 separate retract cylinders, but I guess it would not hold, if the hydraulics do not hold.

Seabee Progress:
I detailed the insrument panel to somewhat resemble pics from the actual plane that I am replicating. I didn't make the lower gauges in the aluminum bezel plate rectangular, like the real plane, and the alum plate is a bit out of scale, like the gauges. I cut out the data plate from a pic of the real instrument panel, and made an attempt to arrange everything to resemble the full size plane that I'm modelling.
The little insrument panel locks in place quite well without even being glued, with a flange that locks onto the fuse former along the window pillar line, and a cut that slides over the front dash frame. Maybe I'll keep it removable and use it as a stash area in "smuggling operations" over the border.:D

The engine cover mold is moving along. I've been using thin coats of DHP filler, as I slowly sculpt it to shape. The filler is nice, even if it is all eventually sanded off, as it makes a good "guide" for sanding when at the nearly finished stage. Pretty much give the same "guide" effect as spraying 2 different color primer colors on top of each other. When you sand high and low areas, you see the color difference between the filler and the foam. Before final sand, I'll add a thin coat of filler to sand smooth, making a tougher mold surface than the foam.

The wing core will need the ends extended and shaped as Horner tips. Other than that, this FlyZone Cub wing is a good fitting core, with basically a Clark-Y airfoil. I stuck it on, just to see how it looks as an airplane, versus the boat I've been staring at for weeks.

Bill

pd1

03-29-2007, 02:43 PM

Bill, that panel looks great.

You should have been the mechanic on the Sea Bee, you spotted the problem in the landing gear system immediately.

Needless to say the mechanic didn't.

When the tail wheel retract piston leaked, the hydraulic pressure dropped. The main gear piston then moved back.
Causing the knee joint to move back from over center.
Causing the main gear to collapse.
Whew.

The mechanic got it after the second gear collapse.
That one was while I was taxiing up a ramp from the river.

That's when I found reverse on the prop to be very helpfull.

And this was the boring part, putting the plane back in the water was the really interresting story.

Your Sea Bee looks better and better, keep up the good work.
Paul

Bill G

03-29-2007, 07:12 PM

Thanks for the comments Paul. Would be nice to have reverse. Maybe I should get one of those variable pitch prop setups and I could hover.:D Actually it would be pretty cool.

I thought I had this "loaf of bread":D engine cover shaped to where I wanted it, and I ended up sanding off almost all the filler, for the second time.:eek: I think I'm finally happy with it. It was too wide, and the front did not curve in sharply enough. The 3-view outlines just aren't enough to make this thing from, and no matter how many photos you look at, it never seems to look quite right. I put a "paper roof" on the plane, so I could get a more realistic view to compare with the photos.

Bill

pd1

03-29-2007, 07:25 PM

Bill G

03-31-2007, 07:35 AM

Reverse is a wonderfully thing to have.

I think it's like having electric windows and door locks on your car, nice but not necessary.

The surprise to others factor is nice too.

Your cowl looks right, with the cowl seams and the front cover seam and grill it will look perfect.

It really looks like a Sea Bee now.
Thanks Paul. That cowl was tough. It is now about 2mm thinnner, and tapers in a hair more at the front, and is perfect. I clear coated and painted it with Testors, so it will have less chance of being eaten as a mold. It still will be covered with Saran wrap, before glassing over it. If I slit the bottom of the prop opening hole in the glass part, after it is made, I can slip it off the mold, and use it again. After all the effort, I plan to.:eek:
The engine cover seams really should be detailed on it also, for scale look. Maybe I'll make a functional flip open cover, like the full size. Definitely will have a wire grill.

Started working with the foam wing core. Its EPP from a FlyZone Super Cub. The foam will accept standard thick CA and activator, which is a bonus. I glued a perimeter frame around it, and will probably sheet the wing with 1/32" balsa. Looking closely in the pic, there is a rear mounting plate fabbed from balsa airfoil stock, that is glued into an area cut out in the back of the wing, and under the engine cover. This will provide a reinforced area for a hold-down bolt. The front of the wing will be plated, and locate to the plane with indexing pins. The perimeter frame will also create a wing with a longer chord, when sheeted over. This wing is basically like the Clark-Y on the full-size Seabee, but is quite thick, and the maximum camber point is pretty far forward. The dowel rod that is glued along the front, and a few stringers that will be added above the dowel rod as shims, will create a slightly different airfoil profile when sheeted over. The idea is to get it closer to a Clark-Y, while also extending the chord about 3/8", since it needs to be anyways, for correct scale.
The wing span needed to be extended with flat airfoil shaped plates on the end, which will be used to attach the Horner tips, which have not yet been made. This was also done to achieve a 51.5" span when completed. Some additional balsa formers will be made, which will be cut to mate against the wing panel end surfaces, where they taper off, and will glue to the end plates. These formers will, in effect, act as stringers also, for the sheeting to glue onto, filling in the void area. The work involved in modifying this core is worth it, since I already had it before I thought about this project:D and don't need to spend more loot, but more importantly because its almost perfect for the plane.

Bill

pd1

03-31-2007, 11:56 PM

Bill, what are you going to cover this with?

I read in one of your other posts, over at the other place, you painted "Microlite".
What kind of paint did you use?
What were the results?

Chris F

04-01-2007, 01:08 AM

Hi Bill,

It's taken all this time for the people here to fix my account so I can post messages. It looks like I'm just in time because you're almost finished :eek: .
It's looking great, you have done a fantastic job and I look forward to seeing it in the air. Good to see you here too pd1.

Chris.

up_ya_go

04-01-2007, 01:38 AM

Pardon (the intrusion) .... But I just cannot resist saying you guys have an incredibly interesting, infact incredibly fascinating thread here .
Bet there will be much celebrating !!!!
Cheers
Ray

pd1

04-01-2007, 02:10 AM

Hi Chris, welcome to WattFlyer. Nice to have you here as well.
Nice to have some help in pushing Bill along.

Bill G

04-01-2007, 07:29 AM

Chris, I'll still be a good while, this thing moves along very slowly.:D Actually it may start to move along faster now, after the last major mod, which is what I had to do to make this wing core work, is now mostly finished.:eek: Thanks for posting. I was amazed to see all the interest today.

Up ya go, thanks for the comments. I like to build, and see, different stuff that we don't see everyday.

Paul, the Coverite is tricky to paint, as you have to paint it slooowly, or it will wrinkle, and then you have to very carefully heat shrink it with a hair dryer. Too much heat will pull seams. I started using it, since it is very light, and will paint well with a very light coating. I got into it for small EDF foamies, where weight is critical. I used Testors spray enamel and Testors Model Masters enamels on the Coverite. One nice thing about it is that you can easily stretch it over any surface, with low heat, which foam likes. My GWS 262 in my gallery is an example of a painted Microlite plane.
This plane will be a Monokote job.

Cutaway Ailerons
I got talked into ailerons at another site, which is a good thing, since I may as well go the extra effort at this point.

Looking at the wing extension framing in the first pic, I added an extra plate at the aileron hinge line, which is not glued to the first plate. I will cut through the sheeting between these two plates, after it is sheeted, and the aileron will separate from the wing, with a partial hinge plate on both the wing and the ailerons.

In the second pic, a hinge plate can be seen, that will be glued to the wing, at the hinge line, which will cover the exposed foam, and make a complete frame that will accept hinges. I also laminated an extra piece of 1/32" balsa behind this plate, where the inner most hinge will insert, since the hinge would rip out of a single layer of 1/32" balsa. A small recess was cut into the foam on the hinge line, to allow for this added laminated piece. Plates like the one just described will be added to the hinge face on the ailerons that are cut away also.

Looking again at the first pic, a balsa insert can be seen, that was inserted into a slot cut into the wing, which will be the aileron perimeter frame along the cutout on the wing. Glue was added only to the wing side of this part as it was slid in, so the aileron can "fall" away, after the sheeting is cut through at this line. A plate like this will need to be added to the aileron also, after it is cut away. The side of the aileron will be shaved down by the thickness of this plate plus a bit of clearance, so that the aileron will be the correct width for the cutout, when completed.

For what its worth, since its not often that folks modify a FlyZone Super Cub wing core this way, it did work well for extending the ends and adding ailerons to a foam core wing.
The additional effort of working ailerons into the wing extensions was fairly easy, since the parts only required a few perimeter plates to be added, after cutting the ailerons away from the wing, after sheeting the ends. The benefit is that the wing extension was sheeted as a single entity before cutting away the alierons, so that everything would be straight and true. I've learned the importance of building wings without warps, where both panels are symmetric from the center, in the past. http://www.rcfreedom.com/Smileys/default/shocked.gif :eek:

Finished the ailerons and cut hinge slots. (Pic 3)
4.5grams each is definitely better than using solid balsa. :eek:
The airfoil front profile is now closer to the actual Seabee. The bottom sheeting still needs to be added to the wing extensions.

Bill

Bill G

04-02-2007, 08:50 AM

Working on the wing saddle and removable roof with skylight design. This stuff moves slooow. In the pic, there are 2 header plates made for the wing front dowel pin locators. The wing will have to be shimmed up to simulate the compressed height of the foam seal that will go under the wing, before drilling the dowel holes. The sealing scheme, and building the roof itself, will be a bit of work. Just making the 2 dowel pin plates, and tweaking the shapes was a few hours:eek:.

Two notched areas can be seen, looking at the cutout on the wing (an arrow from a pen marking is at the spot), where it locates onto the fuse. These areas will require fillets that will mate against the curved roof below. The pic of the real Seabee shows this small area on the top of the wing and near the front of the engine cover, which is painted the same blue color as the top of the wing. Just another example of all the little parts that need to be made.

Not in the pic, is some padding done to the roofline flange. I don't want to make a roof with a bunch of custom made dips:eek:, so I had to
straighten the flange surface by padding with hard, thin sheet balsa, and block sanding. This area is yet another area that needs to seal perfectly.

Bill

pd1

04-02-2007, 02:26 PM

Bill G

04-03-2007, 05:14 AM

Bill, You're right about sealing the roof hatch.

Transitioning from displacement taxiing to getting on the step, a lot of spray can go up.

That's why a lot of the Sea Bees had larger spray rails added.
Even with the wide spray rails water can shoot up over the wing.

After all this fine effort we wouldn't want to see the equipment get wet.

How are you going to mount the tip floats?
What are you going to make them out of?

The flight videos I previously posted of a Seabee from modified RCM plans show quite a bit of spray.:eek: The model is the same size as my build. Looks like it takes a good bit of both power and time to take off also. As for sealing, I'm trying to build this so that it can be darn near submerged without leakage.:D I don't want a single drop in there.

I've been thinking about the float tips. One thought is to make them from molded half parts, like the Guillows pilots and bombs, except using fiberglass. The full size floats are made this way, with a seam in the center. The easy way would be to sculpt them from balsa and waterproof them with a coating, but this thing is getting heavy enough as it is.:eek:
Haven't thought about the mounting convention yet. I'd like to mount them with a flexible/spring setup that can give way, if needed, versus breaking off. Other thought would be to hinge them and make the support strut with something like an EZ link on one end, so they could be folded against the wing, for transporting. I'll be thinking about the floats for a while.:eek: Too many options.

Bill

Bill G

04-04-2007, 08:40 AM

The first pic shows the wing saddle parts and dihedral braces, with the notched wing core standing up in the background. The foam wing core is tough to visualize in the pic, since its on a white table.:eek: The dihedral braces will be glued to the wing saddle plate. The braces aren't really necessary since the plane will have wing struts, but will stiffen it a bit, increase the adhesion area of the wing saddle plate when epoxied onto the foam core, and make the wing a stronger when removed from the plane. These ply parts were all lightned with holes, which I've tried to do with any parts I can. The fuse mounted plate has light balsa inserts glued into cutouts in the part, for weight savings, and all parts were coated for waterproofing when finished. The locator pins are mounted in the cabin wing saddle plate, since the wing seal will be on the wing bottom surface, and water could leak in around the pins, if the convention was reversed. They are mounted low enough on the saddle plate to not interfere with the removable roof, which will be made soon. I didn't want to mount the front wing seal between the mounting plates, since it would create a gap in the roofline, detracting from appearance. A continuous seal on 1 single surface will work better too. The wing saddle locating plates will also serve as formers for the curved roof.

The second pic shows the wing sitting on its mount, and the locating pins on the cabin. The pins were difficult to locate, since both the wing bottom sheeting (not yet installed) and the compressed seal thickness had to be simulated with a sheet of balsa used as a shim, while locating the holes.

There will be some type of removable hold down bolt/s in the rear of the wing mounted under the engine cover. One method is to use 2 bolts mounted a bit forward of the rear cabin "V" point, and on the sides to make the bolts accessible, since the prop shaft will make the center area inaccessible. This will be needed, unless there is enough clearance to get in there with a wrench.:eek: More issues.

The last pic shows the taillights with removable 12V bulbs in the rudder. The wings will have red and green tip lights also.

Bill

pd1

04-04-2007, 02:25 PM

Bill G

04-04-2007, 06:54 PM

Hi Bill, I used to fly a lot of R/C seaplanes before, one trick we used to help keep water out of the cabin was to cover the fuselage opening with scrap Monocote.
If we had to access the inside we just cut it away, then replaced it.

If you have to have continual access to the interior, maybe you can tape some Saran Wrap over the opening. It won't stop a flood, but it should help stop spray from entering.
Paul

The removable roof will have a seal, since it will have to be removed every flight for the battery. It will be the same scheme as the wing seal, being a compression seal on the flat flange on the top of the cabin. This plane will be submergeable when finished. The wires for the rudder lights will be sealed at the exit point of the fuse. The tailwheel is sealed with fuel tubing stretched over the torque rod sleeve at the exit, where the inner rod can rotate inside the tubing, but with a water tight fit. The same thing will be done with the main pivot rod for the front wheels. I even tested the pushrod fit, and with 2 inches minumum of sleeving at points that exit the fuse, the surface tension is enough to keep water from leaking past the pushrod inside the tubing. This is unless it would be under a depth deep enough to create significant water pressure, but then again, considering the air volume inside the plane, it would be like trying to sink a beachball:eek:. I'm building it like a submarine:D.

The good thing about building yourself is that you can design sealing, and other features, that you would not get with a Great Planes ARF. On the other hand, it builds a lot slower too.:eek:

Bill

Bill G

04-05-2007, 06:24 AM

Made the attachment plates for the wing struts and float mounts, which need to be epoxied in place before sheeting. The foamcore surface has been recessed for these plates, to create a continuous sheeting surface. I used aileron clevis parts for the wing strut mounts, which are secured with epoxy underneath the mounting plates. The mounting tabs for the wing floats are made using Klett aileron horns. This is the first EPP wing core I've used, and I'm quite impressed with how well parts can be both epoxied and CA'd to the foam. Much better than cheap bead foam where the parts rip out. The wingtip lights are now wired, also with a landing light on the left wing outer leading edge. Still need to route the aileron cables before sheeting.

Bill

Bill G

04-06-2007, 06:48 PM

Finished hinging the ailerons and tail feathers. The ailerons had a large flat hinge surface, so I added and shaped 1/16" sheet balsa to the hinge face on the ailerons, and rounded it (first 2 pics). The mating face on the wing was dished out to mate with this rounded face, by adding strips of sheet balsa to the top and bottom of the hinge face, and dishing the area out with sandpaper. The ailerons can now move a reasonable distance up and down, without a large gap.

Slotting the tail surfaces for hinges was easy. Usually, you have to be careful to hold the frames while slotting to not crush them, with light non/sheeted, stringered frames. These frames have so many stringers:eek: (which will simulate the metal sheet ribbing when covered), that the slotting tool could easily be pushed through the frames, with the frames standing vertically on the table.

The wing landing light can be seen in the third pic. The tinted plastic light cover was made by scuffing with fine paper and rubbing with pastel (grease pencil) to tint the plastic. The full size plane I am replicating has a tinted cover, and it also hides the imperfections in the aluminum light dish in the wing, made by working aluminized duct tape into the light recess area. The outside perimeter of the light cover will be neatly trimmed over with the iron-on covering, which will be applied last, over the plastic lens cover perimeter. This landing light can be seen in the last picture, on the full size plane.

At the rate that all these little details move along, I'd say this thread will be easily going for at least another month or 2.:eek:

Bill

ElectricFlyGuy

04-06-2007, 07:28 PM

Awsome job Bill!!!!! I want to build me some planes to fly off my small lake! Where did you find that pic of a real seaplane? Take care and I hope you win that contest :) :). Scott.

Bill G

04-07-2007, 08:18 AM

Awsome job Bill!!!!! I want to build me some planes to fly off my small lake! Where did you find that pic of a real seaplane? Take care and I hope you win that contest :) :). Scott.

Thanks E-FlyGuy
Airliners.net and some other sites have some interesting info. I was surprised, that there are a few dedicated non-profit Seabee sites and owner society sites, that are simply incredible, with a wealth of info and pics. The one I'm replicating is actually in several sites, and the owner seems to be a regular at Fun-in-Sun fly-ins also.
http://www.republicseabee.com/
http://www.seabee.info/seabee.htm

Seabee Progress
Well the picture's crap:eek:, but I installed the aileron cables, and am now ready to finish sheeting the wing. I teetered between either using individual servos, or a single servo with Sullivan Gold cables, for a while. The E-Z links used on the aileron horns are HobbyZone thumbwheel threaded links. I've been using them for a while now. They are fine threaded, unlike the Dubro E-Z link screw threads, so you can get incredible tightening force on the pushrod with just your fingers turning the ribbed thumbwheel. Fine threads don't back off as easily as coarse threads do either. I'm convinced that they will tighten as well by hand, as the screw versions do when using a screwdriver. They also seem to be made of high grade steel, and are only a buck for 2 of them. You can tighten the crap out of them, and the threaded thumbwheel screw will not break. They are much easier to adjust with your fingers, than needing a screwdriver for the Dubro links.

The second pic is about as much as its looked like a Seabee as of yet. Every now and then, I have to throw it all together to see a real airplane instead of a bunch of parts, to keep motivated.:D

Bill

Chris F

04-07-2007, 10:45 PM

Hi Bill,

It's looking fantastic. It's the best, most scale looking Seabee I have seen yet. It looks to me like you're still making good progress.

Chris.

Bill G

04-08-2007, 06:59 AM

Thanks Chris. Making good progress, but slow.:D Everything's different than other planes I've built. Today's work is about as good as an example as it gets, as I've never mounted a motor on the top rear of a high winger, with a cabin that comes to a point underneath.:eek:

I was about to start sheeting the wing today, and I thought it might not be a good idea to mount 300W of takeoff power on foam.:eek: Anyways, I had to take a step back once again, and design the motor mount and decide on the wing hold down location. Its a lot easier to build the mounting structure into the wing core now, than to cut into it after sheeting.

I started by adding a hard balsa brace of rectangular stock from the wing leading edge to trailing edge mounting plates, which was shaped to blend with the airfoil. This piece runs down the top center of the wing chord, and will also give a point for the sheeting to fasten to, in the center. I also extended the ply plate on the top rear of the wing, which is glued over the brace just described. I need the added area for the wing hold down bolts, since I don't want the bolt to be trapped under the motor. Originally I wanted a single bolt in the rear, but the motor would have to be removed to access it, so I'm going with 2 bolts, 1 on each side, about 1-1/2" forward of the trailing edge. I'll attach blind fasteners to the top cabin flange on the inside face, for the wing hold down bolts to thread into, with a cross-brace across the underside of the flanges for strength.

I found some light aluminum computer brackets with threaded PEM fasteners already installed in them, in my hardware drawers. Scratch builders collect junk like this with a passion.:D I bent them for the motor mount brackets as seen in the pic, and are obviously not finished. They will need to be mounted on a shim block, which will lift the motor to the correct height, and downthrust angle.

Bill

Bill G

04-09-2007, 06:47 AM

Well its not exactly a laser light setup:D, but I made a crude tool to adjust the motor mount block to produce 3 degrees of downthrust, like the full size plane. Still better than that TLAR stuff. The custom made motor mount has 4 threaded inserts in the aluminum frame, that will accept screws installed from the wing bottom surface. The foam wing core has been reinforced with hard balsa and ply in the motor mounting area and also has a brace that runs though the center chord, to tie the front and rear mounting plates of the wing together.

The wing mounting holes, tubing liners that are glued inside the holes, and the placement of the threaded inserts in the cabin top flange were located with a high degree of accuracy. This is the kind of stuff that makes these scratch builds take forever.:eek: If you don't try to work within a tolerance of +/-.010", then you will end up with a wing saddle plate that does not butt perfectly with the cabin, and bolts that require game playing to get the threads started. The 10-32 nylon wing bolts drop into the tubing inserts and thread effortlessly. When fully tightened, the unthreaded bolt shank at the top fits inside the tubing with only a few thousandths clearance, for a precision fit. The tubing inserts are located inside ply plates which are attached to the wing center balsa framer, since they would rip through the soft foam core, without this positive support.

The top wing sheeting panels have been pre-cut to fit like a glove, so I pre-drilled the motor mount and wing hold-down holes in them, so I won't have to find them later, since they would have been buried under the sheeting.

Custom Gearbox City:eek:
The gearbox came with my Great Planes foam ARF Hellcat. I used a different drive gear, and have a final ratio of about 3.1:1. I drilled out the gear and machined a small half-round on the inside surface of the inner gear hole. Using the correct size of wire to make a keyway, it can be pressed in-between the flat on the motor shaft, and this half-round hole, which locks the gear on the motor shaft. It is tight and works well. My only concern is that there is not that much meat left in the gear body after the machining, so I hope it doesn't explode under power, but it is working well. Stop collars were used on either side of the gear, to stop it from sliding on the shaft. Opposing the set screws of these 2 stop collars 180 degrees apart keeps them in balance on the motor shaft.

If you get a kick out of this gearbox, you outta see what's in the Hellcat now.:D
It has an LPS gearbox, which suffered some melting damage in a Feigao meltdown, with a 180 brushed motor now custom mounted on it with wire tie and globs of CA. Has many great flights (over 30) on it, using 3s lipo to boot!

The Motor
I'm not betting the farm on the motor,:eek: but it is a Maxx 4011 cobalt. I've been trying to hide this motor from the thread, since I know that it will be questioned skeptically and will cause a million "go brushless" comments. I may end up doing that anyways. They are good for about 250W on 3s lipo, and can peak at 300W for takeoff. Theoretically, I can run at about 9500rpm with a Master Airscrew 9070 3-blader, using my 3.1:1 gear ratio on 3s lipo.

Moto Calc Anyone?
While some of the motor calc software is a bit conservative, I'd be interested to see the results of the setup, if anyone wants to run it?

Why use it? Because I have it.:D Also, by using a geared setup, the motor is moved forward, which helps avoid the need for added noseweight. If I use an outrunner, then the motor will either fit in the very rearmost part of the engine cover area, or will require a driveshaft extension with a carrier bearing.

note: engine cover: full size plane. Don't correct me, and say motor now.:D

Bill