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Old 07-24-2008, 09:22 PM   #527
DBacon
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Larry,

Yes my hinges are as you say, criss-crossed, I will make a drawing and add it to this post. BUT - THE HINGES FOR THE CAP are just strips of Monocote 2.5" x 1" hot glued in place, no ironing at all.
I came up with a neat way to apply them, take a plastic ruler, 1" wide, wrap the end with masking tape, inside out (!!!) and it becomes a grabber to hold the hinge. Slap a hinge against it, add glue to the hinge, and press it in place, hold until cold and peel off the homemade grabber tool.
**** EDIT y09m10d14 I have been using RTV hinges lately, takes a day to cure, but work well-see later posts ****

I will post my accumulated notes, all copies of what you have said, so it should sound familiar. I added some notes, and edited things, but it is true plagarism at it's finest. As Sir Francis Bacon said "plagarism is the most sincere form of appreciation" (NOT AN EXACT QUOTE...) Here are your notes:

1.WATERPROOFING, 2.MOTOR, 3.CG, 4.CONTROLS, 5.PAINT,
6.THRUST LINE, 7.GLUE, 8.BUILD STEPS, 9.TRIMMING
================================
1. WATERPROOFING

If you plan to fly off water - get some CorrosionX water proofing stuff. They have it at the Ace hardware/lumber yard next door to the hobby shop. It can be found in most Ace hardware stores and many Marine supply stores.
Get the standard (NOT the heavy duty) Marine or Aviation CorrosionX. I prefer the pump spray bottle and not the aerosol spray can, but either will work. The pump spray is a lot easier and neater because you can take the lid off to poor it into a jar for use. The aerosol can is a lot of trouble to get some into a jar for dunking. You will waist a lot.
This stuff is like medium weight oil - about 20-30 weight or so.

Pour some into a large mouth glass jar or small deep bowl. Make it enough to completely cover the parts. Dunk the rx, speed control and motor into the jar and swish it around so that the stuff penetrates all the nooks and crannies. Take the rx case off, if you can, so the gunk can get to the electronics easily. It needs to contact and coat the electronic circuit boards.
Make sure it gets inside the heat shrink on the speed controller too. Get all the air bubbles out. Also be sure all the connectors get a dose.
Once the part is all coated remove it from the oil - I use long nose pliers - and let most of the stuff drip back into the jar. I then put the parts onto several layers of paper towels and let them drain over night. Turn the stuff a couple of times to try to get as much of the oil to drain out as possible. Wipe the outsides of everything off as best you can with more paper towels. Then wipe it again - then wipe it again - then wipe it again and again etc.

Be warned - this stuff stinks some (my wife hates it) and if you get any onto something else you will never get glue or tape or paint to stick to that place again. Its a good idea to wash your hands very very well after using it and before touching anything else. Its persistent stuff!
You may think you have drained the part very very well and then lay it down on your wife's pretty new kitchen table - your doomed because another drop will decide to drain out just then
If you want to use sticky back Velcro on the rx or speed controller, you will need to wipe the outside of the case or shrink tubing down with alcohol to get it as clean as possible or the sticky will never stick. Don't get the alcohol on the electronics as that will remove the waterproofing. It also may kill the circuit.
Sounds like a lot of trouble but it will save you blowing up a speed controller or rx if (when) it gets dunked under water. Believe me - if you fly off water it will end up upside down at some point!

I have deliberately run treated motors and controllers and rx's while they were completely under water. Amazing stuff. The TV commercial shows them treating a TV set then tossing it into a swimming pool and watching TV under water.
I put a lid on the used CorrosionX left in the jar and keep using it till its gone. Keep a lid on it as it stinks and may evaporate over time. If you can get the bottle instead of the can you can poor it back in.
I re-treat my stuff once a year and it is doing great. The only things that it didn't work well on were servos. 1 out of 3 or 4 went bad when treated.

On my Capricorn, itís not unusual for the plane to get blown over upside down in the water. (itís the wind - not dumb thumbs.) More often than not, that same wind will catch it and blow it right side up again. So far, I have been able to wait a few moments and fly off the water again as if nothing had happened. I have had the plane upside down for as long as 15-20 minutes with the receiver, controller and motor completely submerged the entire time. When it flips back upright again - off I go with no issues. I have found that sometimes it doesn't work. If water is touching the pins on the receiver crystal it will de-tune the receiver and it wonít work until the water drains off the crystal. If that happens, just remove the crystal and blow on the socket and you good to go again.

I do NOT treat servos as mentioned above. Too many of them die on me. I also do NOT treat my batteries. There is tape covering the electrical contacts on most all battery packs. The CorrosionX causes the tape to stop sticking and uncovers the contacts. Not a good thing.
After a dunking I do NOT use that battery pack again that day. I take it home and put the battery in front of a fan to dry it out as best I can. I leave it there for at least a day before re-charging. So far, after many many dunkings, I have had no battery problems.

Do NOT fly off salt water. It will kill the battery packs in just a few minutes and I don't know how well the CorrosionX would work on protecting the esc's and RX's in salt conditions. They use it for Marine electronics, but they don't normally expect a complete dunking in salt water.
CorrosionX is truly amazing stuff.

P.S. Do NOT be tempted to run your motor while its under water with a prop attached to try to 'motor boat' back to shore. The water has soooo much extra resistance compared to air that the motor will draw huge currents and over load. You will probably kill the controller or battery if you try it.
As always with electrics - the FIRST thing to do if you crash - on water or land - is kill the throttle.
2. MOTOR

Any small brushless will work fine if it can put out 100 watts or more peak and you could probably fly "sport" with as little as 60 watts.
The wing loading of a typical shock flyer is about 4.5 ounces per sq foot. A Tensor 4D is down to about 3.5 oz/ft. The Capricorn is about 2.5 oz/ft at the lightest.
My latest version weighs around 16-18 ounces all up and I like flying it on a Mikrodan 2505 motor with a 3S TP 1320 pack. It draws about 9 amps for around 100 watts peak with a GWS 9x5 prop. Itís more than light enough to fly in the smallest spaces or indoors yet still has plenty of power for wild maneuvers and water or wet grass takeoffs and is a hoot to fly outdoors in the wind.
The vast majority of each flight is spent well under 1/2 throttle.




3. CG

I like flying with my CG about 9-10 inches back from the leading edge. I have flown it as far as 15" back but thatís a bit much.
Jed and most other folks prefer being about 7-8 inches back - right at the rear of the sponsons. Itís a lot more stable and tracks better with it at that point.
However, if you want to do those super tight loops you need it back about 9".

When your flying off water and the model gets wet, the CG moves back a good bit. Again because most of the surface area is behind the CG anything added to the entire surface moves the CG rearward.
Itís more noticeable the further back your CG us to start with. If you have your cg around 7" back it wont be a problem, but be prepared for a more sensitive elevator response.
4. CONTROLS

Specific Control Hardware

1. AXI 2212/26 motor (towerhobbies.com) or a torque t22/930 from (extremeflightrc.com)
2. APC 11x4.7 prop--towerhobbies
3. Berg 4 receiver----towerhobbies
4. Thunderbird 36 speed control---towerhobbies
5. 1800-2600 3 cell lipo battery---cheapbatterypacks.com
6. Velcro to stick everything together
7. Blenderm tape for hinges.. top and bottom----medical store or on line
8. HS 55 servos or HS 65 servo---towerhobbies
9. Krylon H2O paint...It must be H2O or it will eat the foam----Walmart
10. Dubro 930 horns---towerhobbies
11. Durbro easy connecter---towerhobbies
Controls - General

HS55's servos seem to have plenty of power. I have stripped out several of them after crashes though. I like the '55's because they are cheap and have enough power, but also because if you bump a surface while loading etc it will NOT automatically strip the gears like some of the small servos do.

Original has enough ground clearance for a 16" prop so on my next one I will mount the motor down lower - even with the top of the main wing. That will reduce the need for so much UP thrust .

HEAT SHRINK - I haven't had any fail in flight, but I have had a couple tear after hard crashes that also stripped out the servo gears.
Some heat shrink seems to be better than others though. I had some that was kind of stiff before shrinking. Felt more like drinking straw plastic rather than the usual rubbery stretchy kind. That stuff didn't work at all. It tended to break after just a couple of bends once it cooled.
Just remember to sand the ends of the carbon rods smooth so they are not sharp and have no rough edges. Also bend the joint 90 degrees as you shrink it - in the direction its going to be working once its installed - and let it cool in that position.

The elevon push rods were made from 1/8" carbon tube split down the middle. The last inch or so is not split and has an outer sleeve to stop the split at that point. The back of the push rods have 1" bits of threaded rod lashed and glued in place. The clevises go on the threaded rod and allow individual adjustment of each elevon.

Pull-pull could be tried as per design on ďPull-pull.dwgĒ

I decided to do all the hinges and servo work before putting the W into the wing; much easier to work with everything flat. The wing panels are joined with tape at this time to allow them to hinge and form the W easily.
Added water rudder area is glued on bottom of fin for better water steering.

The only other change I make in the tx is to run a lot of expo. I generally use around 60%-70% expo on elevator and aileron. Zero on rudder. I dont use dual rates - Im maxed out all the time.

However, thats because of the way I like to fly.

How you set up the controlls as far as throws, expo, dual rates, etc depends mostly on how you like to fly.

I like to fly on the ragged edge with this thing - very tail heavy and as much throw as physically possible. The rudder goes about 60 degrees either way and the elevons go around 50 degrees up/down on mine.

Thats what you need if your going to do wild manovers one second then slow to a crawl the next and cruise 1 inch off the water or drag one sponson around the circle. Thats also why I fly with 60%-70% expo so I can keep it stable and smooth at slow speeds and still do wild stuff without having to flip a switch.

Most people have a hard time with that, but its what Im used to.

I would recommend you start off with a mild set-up to get started unless you are a wild 3D junkie who like to do low inverted spins and tumbles at hi speed.

I would set things up with about 45 degrees of throw on hi rates and mabey 15-20 degrees on low rates and set the CG at around 7 inches from the pointed nose to start.

Fly it and see how you like it. Adjust the throws and cg to taste as you get used to it.

This thing flys a bit differently than most any other plane out there and it takes a bit of adjusting.

The best advice I can give you is:

1) dont fly at full throttle all the time. This thing will take off and cruise around nice and easy at very low throttle settings. Its a ***** cat at slow speeds. It can get a little psychotic at hi speeds and a rear CG

2) Use the left stick.

I do 90% of my turning with the rudder. When Iím low-n-slow I control altitude with throttle and use the elevator to set the angle of attack and steer with rudder.

I have use several different things for color. The sponsons are painted - mostly with Krylon H2O but Iíve used other latex paints as well. On the wing I am currently using some low temp covering material - I think its UltraCoat but canít remember for sure - the labels are long gone I have also done hand painted stripes with craft paint and a foam brush when I was in a hurry.

Regular Monocoat is not a good idea as the shrink temps are too hi and the foam will melt. Make sure what you use says 'low temp' somewhere on the label.

5. PAINT

Be careful with paint. If you paint the entire thing it adds a LOT of weight. Thatís a lot of area and it adds up. It also tends to make the model more tail heavy so keep that in mind too as most of the paint added will be behind the CG.
6. THRUST LINE

On thrust angles - how much up thrust you need varies depending on how hi the motor is mounted above the top V joint.
The taller the motor mount, the more up thrust you need.
On my small version, I was able to mount the motor very low - right on the V. That one didnít need any up thrust.
Lowering the motor height caused more of a change than I expected in the thrust line. I think Iím going to have to add some DOWN thrust.
I wonít make that decision until I get a chance to fly it outdoors and do some more trimming flights. I need to get the CG right before I mess with the thrust angle. I think the CG needs to go back more too, but I need some more room to test that properly. Our indoor space is just too small to allow for proper trimming. Youíre constantly turning to miss the walls!
Also got to do some trimming flights. I think the thrust line is fine. The CG just needed to go back a good ways. Iím almost perfect now.
Right thrust isnít critical. This isnít a pattern plane and I doubt you'd notice if it was set to zero. I wouldnít bother trying to cut the slots on an angle.
What I do is just glue the stick on slightly cocked to one side, then add a side brace in Depron. Sometimes I have done a brace on both sides when Iím running larger motors.
All of mine do have a small amount of right thrust. I donít measure it - its TLAR
7. GLUE

For glue on the main wing joints - Gorilla brand glue or any similar expanding Polyurethane type glue will work best by far. I like the Sumo brand because its white and looks the best. It has the worst bottles though. Very tough to squeeze. I have used CA and epoxy but they seem to be more brittle and the joints have broken easier.
I usually use foam safe CA on the motor mount and to glue in the rudder but the PU or epoxy will work as well.
My current favorite for the wing joints - by far - is the new Gorilla Fast Cure clear polyurethane glue that dries white. I also like the Sumo brand but the bottles are tough to squeeze. I use some foam safe CA here and there when Iím in a hurry.
I just found some new Gorilla glue.
It looks clear in the bottle and says "Quick Cure/Dries White".
I just tried some and it does dry faster and ends up white.
The bottle is much easier to work with than the Sumo glue too.
I like it a lot so far.



8. BUILD STEPS


I found out that the blue is Styrofoam and the pink is the cyanosomething?
That means that the blue would be relatively safe to cut with a hot wire, but the pink will put out very very nasty fumes.

1) After you cut the main wing parts out, bevel them for joints and for hinges. Since Blenderm tap slowly ďcreepsĒ, use modified Monocote hinges, requiring two V-shaped mating edges, ===><===.

2) Start with the 2 panels on one side and bevel then tape the outside of the joint while its laying flat.
3) Turn it over and add glue to the joint.
4) Weight the inside piece and prop up the outside tapered piece 4" to 5" off the table. That will give the proper angle. Brace it some way so it canít move while the glue cures. I use scraps of Depron and some pins.
5) As the polyurethane glue cures, it will expand up out of the joint. During the first 1/2 hour or so you can run a Popsicle stick over the joint and scrape off the excess as it comes out. You will end up with a nice joint if you stay after it from the beginning. Wait too long and you'll have to sand it or try to cut it off. Mix the glue with water first to speed it up.

Once the outer panels are done, you can do the center joint the same way. Pre-cut the slots for rudder then put glue in the joint then flip it right side up and put braces at each end then let the glue cure. I donít bother scraping out the excess as it foams up because it will not show and its impossible to get to using this method anyway

A note on the angle of the outer panels - it doesnít matter
I just checked and I have 3 different bend angles on various versions. Prop up the outer panels anywhere from 4" to 5". They all fly fine ")

The sponsons are made from 2" thick pink building insulation board. I get mine from Home Depot in 2' wide x 8' long sheets for about $20 or so
I have also used pool toy "Noodle board" foam for the sponsons. It has the advantage of being similar to EPP foam in that it bends and springs back after a crash. The down side is that is a pain to work with as far as getting glues to stick and it only comes in ugly colors.

Try painting or low temp iron-on covering to waterproof the foam, if it absorbs water (Blue, Pink, Expanded bead, Styrofoam all absorb water.) This is still an unconquered problem. May try Depron in an inverted ďTĒ or a channel with an open back for drainage.

Larry covers the bottoms of his sponsons with plastic cut from large jugs of cat litter. Glued on with 3M 77 spray adhesive. It lasts forever and is very slick. Works better on grass and snow than duct tape, though Duct tape will work and is cheep and easy. It wears out fast on pavement but is easy to replace.
Others have had good luck with the thin baking sheets from Target. They are Teflon or something similar. Very slick and tough but pricey.

Put the electrical components in the space between the deck and the under brace - you will have to make the brace width to fit. Lay this out first and cut the fin slot before final assembly
Seal up the front unless you suspect overheating is a problem.
In the winter it would probably help keep the packs warmer so you would actually get better performance on very cold days.
Be sure to leave the back end open so any water that does get inside can drain out.

To mount the sponsons cut a 'v' shaped notch in the top and then glue them to the outer joints of the 'w'. The angles donít have to be perfect - the Gorilla glue will expand to fill in any gaps.

Servos - wrap with masking tape glue them down, on top of the wing.
Donít cut a hole in the deck for servos; mine have been filing up with water since I did that.

Wing strength, two choices:
1. Double up the layers in the front, for strength. It also makes the plane stiffer so it rolls better. It keeps the main wing from breaking at the join line where the under brace glues to the wing deck.
On hard landings the sponsons tend to spread outward. That puts a bending moment on the center wing panels and it tends to break along the line where the brace is glued on.
2. A dowel running between the sponsons works well. It can get caught on tall weeds It is a lot stronger though.

My doubled-up section holds up fairly well but it still can break along that joint on a rough landing. Last time I broke it I glassed the joints about 4" back with .5 oz glass and water based varathane.
Keep in mind I tend to be rough on mine. I like to fly close to the ground/water and many of my low loops tend to bottom out an inch or so below ground level. The "spring action" of this design allows it to flex and come back - but only so far
This thing is long and flexible as far as twisting. When you give it a roll command the fuse has a tendency to twist in the opposite direction which tends to counter act your roll command. The bottom brace was originally added to fight that, then made larger.
When I added the top front layers that really helped a lot. I suspect a wider bottom brace would have the same effect.

I donít like using hollow LE mounted tubes in this situation. The structure needs to be able to flex or it wonít last long. On the 6MM version I think 2.5mm or 3MM rod would be fine.
I still prefer the doubled front edge because it serves a dual purpose - it reduces the wing twist and helps roll rate at the same time.
If you do use carbon - remember I donít have any really good reason NOT to - it needs to be at the front as I mentioned before. Thatís where most of the weight is going to be carried.


9. TRIMMING

By the way - here is how I test for correct thrust angles.
First you must get the CG set correctly. If itís too far forward or too far back, the up thrust cant be set as well.
Again, this isnít a pattern plane so itís not all that critical.
Get the CG where you want it, the closer to ďneutralĒ the better (but twitchier) it will be.
Neutral CG requires no trimming for level flight between inverted and upright.

Next, trim the model so it flies straight and level at full throttle. Then abruptly cut the throttle.
If the model climbs when you chop the throttle, then you have too much down thrust.
If the model abruptly dives, then you have too much UP thrust.
Ideally, the model should start a slow decent with no abrupt up or down pitches when the throttle is cut.
You can also check by starting at low speeds and abruptly go to full power. If the model climbs radically = too much UP thrust.
If it dives = too much down thrust.
Be aware that climbing/diving with throttle changes can also be caused by nose/tail heavy condition so thatís why you set the CG first.

To check right thrust, first go high then point the model at you and dive at about a 45 degree angle - power off.
Trim the rudder for a straight 45 degree glide with no side to side turning. By the way - this is also another way to check for issues - the glide should be dead flat on the 45 with no climb or diving away from the 45 degree line.
Once the rudder trim is set, then do the same thing but do it climbing away going UP on a 45 with power on. Does the model pull to either side? Adjust side thrust as needed.
You can also check by climbing straight up and see which way it pulls, but the 45 degree climb is going to be closer to your normal flying speed, so I like it better.

I also copied your drawing, converted it to inches, and lowered the motor, I will get that added to this post too. Please note that I revised it, use the newer one.

I wil add newer versions as I redraw this, check for newest date "yXXmXXdXX" is year-month-day


Attached Files
File Type: pdf Capricorn y08m07d24.pdf (19.8 KB, 1282 views)
File Type: pdf Monocote Hinges.pdf (14.0 KB, 800 views)
File Type: pdf Capricorn y08m07d27.pdf (21.7 KB, 958 views)
File Type: pdf capricorn y09m09d02d.pdf (68.9 KB, 862 views)
File Type: pdf capricorn y09m10d12a.pdf (72.6 KB, 1274 views)
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