Horsefly Hobbies Foamie Fokker Dr 1 Triplane Build

[timocharis]

A 3-D capable 20-inch span 6.5-oz Dr 1 with triple ailerons. How could I resist? For icing, the video shows them flying in wind that has a nearby flag flapping straight out. Hover looked a bit erratic in that breeze but what the heck.

Plus, you can get a blue version! So of course I did.

So I ordered the kit and Mike Glass mailed it out lickety-split. Email Sunday, plane here on Friday and Monday was a postal holiday! Very nice. Everything was neatly packed and bagged, including an envelope for the 20-page assembly manual.

The first impression darn good. That's also the second and third impressions. Wow, look at the size of the wheels! They're huge. I was also struck by the thick chord, which is probably a good idea. The total wing area (not easily calculated with these shapes) appears to be just shy of 2 sqft for some pretty light wing loading. Even allowing for triplane inefficiency, that's promising.

[timocharis]

In describing the build, I'm only going to pay close attention where I depart from Mike's manual (which is not often -- at least for me. I'm sure if you simply followed the instructions you'd end up with a workable result). He makes the manual available for download at:
http://www.horseflyhobbies.com/Manual.html

In general, I don't follow the work flow in manuals. I try to do subassemblies first, then proceed to assembly and final finishing. I have to 'micro plan' a bit because I don't like to use CA or epoxy glues unless I must -- I far prefer white glue (in particular Canopy Glue) for its strength, flexibility and non-toxic nature. But it's slow to dry.

[timocharis]

Let me take the suspense out of it: it's a weird plane that flies very well.

Like the original, it has lots of adverse yaw and roll, but it's a natural aerobat. Flat spins seem to require a boatload of aileron compensation. Snapping maneuvers are spectacular (with lots of aileron input).

Unlike the original it rolls like a dervish. They're fairly axial, and slow rolls are possible with some power and a touch of correction here and there. Vertical rolling maneuvers are so good they'll make you laugh.

Hover is reasonably stable but not spectacular. Tight inside loops were satisfactory, but outside is a bit flabby. Waterfalls may not be possible without powering up a bit.

The most surprising thing is how nicely it slows down. With just a little bit of noseup, it practically floats around in very small areas.

[timocharis]

I'm running at 14-turn 24awg CDROM build with N50 curved mags driving an 8040 GWS prop. Not a crushing motor, but reasonably strong. For everything but tight outside maneuvers, power was more than adequate.

Initially I'm flying with a TP 730 2s. I have several smaller batteries I'll try eventually, but I'm too early in the learning curve to change all the variables safely. So this one stays fixed for a while.

Aileron servo is a Hobby Electronics HE-540. I favor these for speed and power in a small, light package. The tail feathers are run by two GWS Pico Standards. GWS R4PII receiver, Castle Creations Phoenix 10 ESC.

[timocharis]

I'm already a little familiar with Mike's designs, and know he takes novel approaches. For this plane, he's come up with some very interesting twists.

The first one you confront is the wing leading edges. He has managed to use his laser to score a series of grooves most of the way through the depron near the leading edge, which allows you to fold the front of the wing over. The skin is supported by tape, and you glue the flap down to form a curved leading edge and rudimentary airfoil.

Mike recommends 3/4" tape (of no particular type) for the support. Most folks would probably use scotch tape or equivalent. But I noted this was going to be stretched and tortured, so I opted for 1" Blenderm. It seemed to work fine.

However, rolling the edge over is a challenge. He suggests using spray glue to secure it initially, and final tacking it with a bead of foam-safe CA. Of course, I used white glue, which required some boards to hold the flaps down, plus about 20 lbs of weight (yes, 20 lbs!) to keep the whole mess flat while it dried overnight.

It's all about keeping the trailing edge of the 'flap' securely against the wing. The leading edge will take care of itself. So you can place your weight well back from the leading edge (say, 3/8" or more). This means you can easily see the alignment, and the whole process goes fine with white glue. The idea of trying to do this with CA is scary!

I may have succeeded a bit beyond spec, because I had to cut clearance for the struts on the middle and upper wings. Mike shows a need for clearance only on the upper.

If yours turn out like mine, they'll seem a little flimsy and have a pronounced bow after drying. Don't fret about it. Once the wings are attached to the fuse and the struts mounted, the entire structure frames itself pretty close to square.

[timocharis]

If you're picky, there's no reason to put up with the floppiness. The lower wing has no struts on the bottom to complicate things, so you could run some 3mm flat stock along the front of the tab before folding. Cut about 1mm off the back of the wing and reinforce the back of the wing the same way (ala shockies).

I didn't do this, because I wanted to build as close to stock as I could stand. Knowing what I know now, I would do this, though the plane flies just fine without it. Picky, picky.

[timocharis]

Next you tape on five of six ailerons (one must stay off until the center wing slides through the fuse). In my next departure from instructions, I used double-tape hinges instead of singles (he wants me to just use tape on the top of the wing, but I can't stand to do that. Sorry Mike).

When double-hinging, I prefer to do the bottom tape first (covering the bevel), which is reverse of the normal order. I find this guarantees an adequate gap between for maximum travel. When all is said and done, you end up with a small area where the top and bottom tape meets, making a thin plastic hinge. I force this issue by slipping a thin ruler between the aileron and wing to jam the tapes together.

I used 1" Blenderm for the underside, and 1/2" Blenderm on the top. Again, this seems to work fine.

Next you stick on the six aileron coupling horns. I found it easier to slip them in if the ends of the tabs were 'sharpened' a little bit with an emery board. I moved a little ahead of the instructions by gluing in the aileron control horns at this time.

[timocharis]

If you follow the instructions and place the coupling horns on the bottom of the wings, you'll have a problem later. Since the wings are staggered (as they should be), and _if_ you use more than 30 degrees of aileron deflection, the coupling rods are going to smack against the trailing edges of the lower two ailerons.

I failed to anticipate this problem, and ended up having to cut some nasty slots in my upper aileron surfaces to get free play. They look horrid, and for some reason this really cranked me off. It's ultimately not that serious, but it's should have been noted in the beta stage.

If you want to use the supplied horns, you'll be better served by mounting them on the upper surfaces of the lower ailerons (and on the bottom of the top ailerons). You'll probably still get some interference, but any material you have to remove will just be white foam, and won't look awful.

To outright solve the problem, make a set of horns that extend straight out the back of the ailerons, and make them adequately long. I have always built my bipes this way, so I never actually had reason to see this problem before.

When I first saw the horns, I though "hey, neat. Never thought of doing them that way." Now I know why!

[timocharis]

Mike includes some wire and a template for a fairly complex landing gear. I hate bending gear wire, so I decided to get it over with. It was as bad as any I've done, but turned out okay. The template is right on, so get your result as close to it as you can.

The trickiest part is getting a 90-degree bend of both legs where the entire structure attaches to the fuse. For all the other bends I used needle-nose pliers, but for this one I cranked it into a vise and used a bending bar, then a hammer to get the final few degrees of a perfect right triangle. Mike suggest taking some trouble on this step, and I agree. It does pay off later.

However, don't worry about getting all the way to 90 degrees on that tricky bend. I ended up relieving it a hair anyway, so the gear would cant slightly forward.

Bending the wire is probably the only truly hateful part of the build. I suggest doing it first thing; perhaps it's the first page of the instructions for a good reason.

But it's over fast and you can breathe easier.

[timocharis]

This is an ingenious glue & tape setup that I followed straight up from the instructions. The only grace note was using some 5/8" tape left over from a Shockie instead of the 3/4" recommended. It turned out perfect, so if you have some lying around, go for it.

[timocharis]

Part of this operation is to build a carbon tail skid. I'm tired of noisy tail skids, so I just cut the sucker off. Instead I'm using a DuBro Mini Tail Wheel Bracket and a nifty Sullivan wheel instead. Luxurious!

Yeah, I know that's not "scale," but get real. This kit is not proportional, and does not even have the round cowl of the Dr 1, and has tripled ailerons. You're gonna give me grief about a tail wheel? It's Impressionism, not Photorealism.

There's no trick to hinging the rudder. Mike has a thing for sanding blocks when beveling, but I find a simple, cheap emery board works fine. If you're uncertain about your control, use the edge of a piece of wood or a ruler to "shield" the work from oversanding.

[timocharis]

I troubled over this endlessly. The two halves of the elevator are completely separate. You bevel them, tape them to the stab, then attach a piece of carbon flat stock to keep them 'in sync.'

Mike shows the flat stock attached in the bevel. I didn't see that clearly in the picture, and thought it was supposed to go _behind_ the bevel (I actually considered putting it in the bevel, but worried that my "idea" might limit the travel -- maybe severely. In the end I realized if it's placed near the bevel, you can get full travel by just scuffing the edge of the stab). Since the plane is short-coupled and the elevator doesn't look all that generous, I wanted all the travel I could get. Heck, if I could get more than 90 degrees I'd take it!

So I moved the flat stock _behind_ the bevel. The result is as you might predict: the flat stock no longer fits into the fuse cutout Mike supplies. Oh well. So I carved that out a bit (some of which you'd have to do anyway -- there's no matching cutout in the rudder support. After seeing how well thought out things are and how well they generally fit, I was surprised to notice this oversight!)

Then I discovered my mistake also meant the elevator needed more clearance from the rudder, so I had to reshape the lower front curve with an emory board. Lots of repercussions from this one goof: don't you make the same mistake.

Neither the rudder nor the elevator has slits for their control horns, which is another oddity for this kit. No problem, of course, and this means you can place them at the ideal location for your setup. Which might be what was intended.

This turned out to be useful.

[timocharis]

There are a few places where fine details don't show well in the otherwise excellent printed manual. Mike also has a PDF online. If you download it, you can blow selected images up to HUGE size and see exactly what you're curious about.

In most cases, it isn't important. In this case, I would have been able to see the placement of the flat stock.

No harm, no foul, however. My setup works fine after trimming the top of the fuse a bit.

[timocharis]

No tricks here except for my usual white glue. Everything went together as shown; in fact, the slots and tabs were somewhat loose, allowing easy assembly and some adjustment to square things up.

Since I'm mounting the motor externally, I didn't bother with the stick mount. I like using the slofly motor mount so I can change out various power plants. Also, a round motor on the front just slightly makes the plane look more like a real Dr 1, which had that neato round cowl.

The landing gear mount with three zip ties, and the system works great. Just follow the instructions and you'll be fine.

[timocharis]

The ply box, fuse and landing gear are all just a bit too narrow. I can snugly fit my small Thunderpower 2s batteries into the fuse, but my Kokam 340s (shown as the recommended battery) cause the sides of the fuse to bow out, and feel scary going in.

Further, even the TPs are a bit snug between the gear wires. I really wouldn't want to put a battery tightly between two such wires, especially considering what they might do in the event of a nasty landing or crash.

Even just another 1/16" would have made it spacious in there. I did help out the problem by adding a little ply plate to spread the gear, but it's still just too small.

[timocharis]

I kept looking at the framing to see if there was some logical way to put the servos somewhere rearward in the box, but couldn't really manage it.

By now, the stock servo position was really starting to bug me. I just do not like the idea of having servo wires running past my battery, even if they're buried under a sort of kludgy tray.

So I decided I just couldn't stand it. I had to mount the servos somewhere behind the ply box.

You may decide to go with the stock setup, and obviously it can work. However, it means longer and heavier control rods, plus limited battery movement for CG changes.

It's obvious this wasn't the first servo location Mike tried. There are cutouts for some kind of servos in the 'cockpit floor' that theoretically comes later in the assembly (in fact, I never even put it in).

So servo placement is problematic. Maybe you'll like my solution; I certainly do.

By the way, the aileron servo cutout in the bottom wing appears to be for an HS-50. The interior servo tray is probably for two HE 540 or 490 type servos. Perhaps some Cirrus, Blue Arrow or Bluebird. Mike ain't telling.

[timocharis]

With my resolve to move the servos back, I noted that I'd easily be able to slip the ESC->Battery wire through the now unused motor stick holes in the ply box.

But I forgot to check whether the ESC->Receiver plug would fit, and it won't! This is a great routing channel, and I ended up having to slip the wire between the ply box and middle wing, which works but is less than optimal.

Take some time to figure out your wire routing, even if you're using the stock servo locations.

My decision to compromise the look of the plane and run the motor wire externally was purely pragmatic. I'm forever changing motors to try various winds and types. Anything too complicated would drive me nuts. If I decide on a final setup, get most of the wires into the fuse and it won't look quite so bad. But if you tend to just put a motor on and forget it, and are sure what motor to use, you may have other wiring problems to deal with.

[timocharis]

I never considered one of the new Hackers. They're not getting good local reviews, they're expensive, and they're heavy.

For now the 14-turn CDROM seems fine. I flew for over 10 minutes and used 400 MAH. But I'm sure there are better motors.

The AXI 2204 is probably okay, but has significant internal resistance and doesn't compare all that well against CDROMS, considering the price.

The Lensrc 15-turn got some seriously good reviews as a 2s motor, but I haven't tried one.

Very high on my list would be the Little Screamer Purple Peril, which can do very hot performance 2s (and I see this as a 2s plane, partly because of battery space but also because of weight considerations. I may be wrong, and am thinking about trying a 3s setup to test my assumptions).

A strong choice would probably be the MP Jet AC 22/7-45D, especially if I were building a red plane. Excellent strength and efficiency 2s, but it runs a 9x5 prop. With a 20-inch wingspan, I'm a bit more comfortable with an 8x4 -- I'm already seeing what I suspect is a heavy P-factor.

Worth consideration is the small Feigao motors in a GWS gearbox. I don't like the gear noise, myself, and they generally like to run 3s with a larger prop.

[timocharis]

This may look scary, especially if your first experience with bending Depron was cranking down the leading edges of the wings.

But it's actually a joy. I love the way this fuse goes together! I departed from the instructions only at one point: I stuck the bottom on as the first step. Seemed to me like it would be easier to square it up while the fuse was still flat, and I think I was right.

Otherwise, just do as you're told. When it comes time to bend the fuse around and glue it, you'll find it goes easily and naturally into place. It's a breeze, and it just looks so cool!

I used a couple of small tabs of masking tape to hold it in place while my white glue dried.

Mike glues the firewall cover on before putting the box in; I did it the other way around. I suspect I got a slightly better fit that way, but it was hard to get it into place. It might be better to go with his method, especially if you do them both fairly quickly.

I would seriously consider using white glue on these steps, because it gives you plenty of time to jigger things into exactly the right place.

My firewall had a bit of a complication. I wanted to use the slofly motor mount, which requires clearance for the set screw. It doesn't hurt to give it a bit more support, either. So I cut and drilled a donut for the front of the mount.

[timocharis]

The rudder is a snap. It's a good idea to test fit it before you put glue on, but I had no problems at all. Of course, I also didn't use the skid, so I didn't have to maneuver it through the slot.

You will have to at least trim clearance from the rudder/fuse insert for elevator clearance, and might want to do that before gluing in the rudder assembly.

Before you glue the stab on, make sure you have enough elevator travel. You may have to do some more trimming at this point, even if you installed the carbon flat stock correctly. It's not going to be easy to fix this after you glue the stab on!

Mine was off level by about a degree or so, which meant pressing, fussing and weighting the assembly to get it to dry level. Since it's nearly impossible for the surface to end up perfect, you'll probably have a similar problem. Again, I suggest white glue (or some other slower glue, such as GWS or UHU Por) so you'll have time to make this adjustment.

[timocharis]

My idea was to stick the servos to the side of the fuse, and do it far enough back that I would be able to access the horn screws from the cockpit.

The downside compared to Mike's setup? If a servo blows completely out, it's going to be a major problem to replace it. But it should be doable.

However, this placement allowed me to avoid the heavy wire tubes and use 1.5mm carbon instead. I roughed out the control rods by adding wires with z-bends to the servo end. Then I could slip them through the exit slots in the rear of the fuse and determine where the servos wanted to be. That way, there's no bend or binding, and no need for covers.

Once I knew that, I mounted the servos and braced them. At that point, I could tell where the control horns wanted to mount in the elevator and rudder. I added DuBro Mini-EZ Connects to the horns (I use them whenever possible) and glued them in.

This took a lot of thought and fussing, but would be pretty easy to repeat (not having to make all the decisions and plan it out). Again, you may have a better plan, or may like the stock setup.

[timocharis]

I always try to put the electronics in before major assembly -- as early in the process as possible. It's just a lot easier to make changes or reroute at this point.

Mike's approach to mounting the receiver would work fine. I preferred to move it a bit more forward and orient the plugs downward. This is still easily accessible from the battery tray area, so either system would work fine. My approach gives cleaner wire routing.

I've already had to pull the wires once (I made a little mistake ...) so I know it works out. A little fiddly, but okay.

The ESC is in the "motor" area, where it would probably end up even if the motor were mounted internally. Best to keep those two 'noisy' components close together.

I did end up drilling two holes in the firewall for ESC cooling. Hopefully they're enough. There is some room for air to get out from the tail feather control rod slots, and everything else can easily evacuate through the cockpit.

[timocharis]

If not earlier, install the struts on your lower wing now, giving them time to dry. Why wait? They'll have to go on soon anyway.

For once, I suggest using foam-safe CA on the struts. They do need to be pinched down (as Mike says) and anything else will take forever. Plan on using a little foam-safe accelerator here, too. Make sure each strut joint has set reasonably well before proceeding to the next stage.

Also, pay close attention to the placement of the leading and trailing edges of the struts. It's fairly easy to get them out of true, even with the tabs to help out. Make sure they're covering the slots in the wing.

[timocharis]

Slipping the center wing through the fuse sounds like it's going to be a problem. The tabs do give some resistance, as Mike says. But it's no big deal. If you take your time, they'll survive, and everything snaps into place.

For some weird reason, my best aileron hinge was this last one, done with the wing in place. I did not install the canopy floor, and really don't get why the instructions make such a big deal out of it. Maybe it made sense back when it carried servos, or maybe I'm in for a rude shock down the road.

[timocharis]

It's probably best to route and install your aileron servo before you mount the bottom wing. I'm sure it's possible to do it later, but I can't figure out why you'd want to. Mike has it going in later -- maybe he likes fishing wires around!

Of course, the cutout was the wrong shape for my servo. They always are. However, I didn't like the location anyway. I want to get the aileron servo as far from the ailerons as possible so the control wires can be close to straight.

So I built up the center bottom of the wing and pushed the servo up against the leading edge. Using a somewhat oversize Hitec servo arm (they fit on the HE servos) obviated the need to put bends in the control wire.

I'm sure Mike's setup is fine, and if your servo fits his hole I'd probably just do as he says.

[timocharis]

At this stage, I spotted some glue in the center wing fuse slots since I figured they might be hard to get at later. I used white glue, so there was no rush to get done before it set.

I had to cut slots in the leading edge of the middle wing or the struts would not have fit. Make sure to check for this before you break out the glue -- you might need them too.

The bottom wing should slot in with no problem, and now you get to do the CA Strut Clamp Yoga for a while when joining it to the center wing. Accelerator helps a lot.

This is when you'll see the wings straighten (mostly) back out. You will feel better about them at this point.

On with the upper struts, clamp and hold, and you're almost done. I used foam-safe CA on the cabane tab, but white glue on the bottom of the machine gun. I did not punch out the holes in the Spandau's cooling sleeve -- I thought they looked fine as they were. My wife disagrees.

The top wing will go on easily, but do make sure you cut out the slots as instructed. I used white glue on this stage, since it could just be weighted down and left to dry. This is slightly aggravating because the plane finally looks about right, but it's sitting around for hours with junk all over the top wing.

You're tough. You can take it.

[timocharis]

My tail feather control rods were already in place, so I didn't have to do that. I used Mine EZ-connects on the ailerons, and straight wires.

The aileron interconnects were done largely as Mike suggests, with four little changes.

First, I thought .050 carbon was excessive, so I used 1mm instead. Second, I attached the top carbon to the z-bend wire with thread for a more positive lock.

Third, I used flimsy 1/8" heat shrink to make the other connections. Easier to shrink and looks better.

Fourth, I routed the carbon on the proximal side of the horns to minimize (hah!) the interference from the trailing edges of the ailerons. On the inside, they encounter a deeper part of the aileron cutouts. Small point, but probably correct.

[timocharis]

I like the battery cover, but don't like fussing with tape every time I put a battery in or out. So I used a couple of old motor magnets to hold the rear shut (the front is double-hinged, more or less as the instructions say).

The top one is mounted on some scrap ply; the bottom is just smooshed into the depron and glued in place (foam-safe CA).

Incidentally, I don't think Mike actually tells you how to make the battery cover anywhere in the instructions. It's not rocket science, though. Just take the two sort of crescent-moon-shaped pieces and stick them to the cover, which is a piece of foam with an Iron Cross cut out of it. The orientation of the Moons is obvious when you hold them up to the fuse.

[timocharis]

First, the wheels don't fit the wire. They were designed for something thicker.

Second, the winglet between the wheels should run along the axle line (at least on a real Dr1. Mike has it running near the top of the wheels, between the wires).

Third, the Winglet attaches with flimsy struts, which simply won't work in the long run.

I solved all these problems by running a .070 carbon rod between the landing gear wires. The winglet is mounted atop that on a bit of carbon flat stock. The wheels now track completely true. And the struts no longer serve any support function -- they're just decoration.

I didn't put the wheel covers on. Oh well. The white spoke wheels look fine, and if I do put covers on they will be white, not the color of the plane.

I was a bit concerned about the heavy wheels, but in the end my all-up weight with a 730 2s battery came in at 6.7 ounces, which is within spec.

[timocharis]

Just an excuse to drop in another pic. Looks okay to me. Note this is before the battery cover went on -- the maiden test, actually. Also, there are no struts yet.

Hey, I like this plane!

[flypaper 2]

I left the little wing off the bottom altogether. I need all the spring I can get.:D Sweet flier. Actually take offs and landings are a none event, unlike most DR 1s. Had to make another firewall about an in. back from the front for the Little Screamer. Great write up Tim.

[timocharis]

Thanks! Oops, forgot to sign it. The name's actually Dave.


Dave North

[flypaper 2]

Sorry Dave, should have noticed it under your handle.:p Like you say the fuse could have been a bit wider. I ended up putting the batt. on the side of the fuse just ahead of the mid wing. Just got through making new ail horns glued to the inside edge of the ails and back from the hinge line to get the pushrod wires more inline and help with the ail differential. Don't get me wrong,flies fine as is. This is just tweaking.

[timocharis]

Don't worry about it ... I just added that because of the problem with my sign-on name.

Did you have the same problem with the aileron interconnect horns? Oh, and wouldn't moving the horns back get the wrong aileron differential? (More down than up?)

I don't blame you for just mounting the battery outside. Things are a little bit fiddly in the front of the fuse!

I've been fooling with the CG just a little bit, and it seems like the plane is actually more stable with the weight moved back a bit. Perhaps the recommended starting point is a bit forward of 'conservative'...?

Dave North

[flypaper 2]

Yes, I had to notch out the ail. the same way.The way the ail. servo is, on the bottom of the wing, puts the diff. going the wrong way. Although flat plate wings are better off with no differential. Sorry Mike Glass, some guys can't leave well enough alone.:D Right about the CG. Going to move mine back a bit further yet, till it gets totally out of control, then move it forward a bit.:p I like it so the trim doesn't change when you go inverted, in other words , no down el. needed.

[timocharis]

Gord --

I do note a tendency to drop a wing hard in some turns, but that's usually a rudder turn. I'm not sure what effect I'm seeing from aileron incidence, but there's gotta be something!

CG is an uncertain issue for me at this point. The wind keeps changing, so I keep fussing it around trying to find the right spot. Still seem to need a fair amount of elevator inverted, but I am running the flat plate between the wheels (which is probably slightly off incidence at all times, since it can torque a bit from the airflow, I'm sure).

Flies great though! Still trying to fight it into knife; I seem to get close and then whoops! I'm kinda hung up on the tailslide spins right now -- they're just so funny.


Dave North

[flypaper 2]

Hi Dave:
Eyeball the wings from the back and see if one aileron is slightly lower than the other due to flight trimming. If it is it could be causing that wing to drop. What you might try is set the ailerons to neutral and use the rudder to trim it instead. Not gauranteeing that it will work but it has for me before with planes with bad snapping tendencies. My CG is still at 1 1/2 in from LE. Still playing with CG too. Need the wind to go down to get more flying in. Cranked in much more EL throw with no problems. Made a cowl from the bottom of a beer can. Looks more DR1 ish:D instead of D 7. Have fun. Does some really violent outside snaps.

[watt_the?!]

nice thread Dave....

[flypaper 2]

Don't laugh guys. This is the beer can cowl

[timocharis]

Gord:

You may have a point about the ailerons, but it won't be easy to shake out visually. My wings have a fairly notable bow to them, making exact estimation of the aileron position a bit of a trick. If I build another (which I sorta doubt -- this is a very durable plane. The ply box is saving my tippy butt every day) I'll definitely use my own carbon suggestion.

Wind is killing me too, today. Bit of rain, which isn't much trouble, but the gusty stuff makes it too hard to figure out what's going on.

Watt:
Thanks! We aims to please.

Dave North

[flypaper 2]

delete

[flypaper 2]

Can't figure out how to delete this thing

[timocharis]

I guess we're stuck with it now! Looks like you flew hard into that beer can.


Dave

[flypaper 2]

Good thing the cowl turned out on the first beer :D Made a pilot but can't get the pic to work.

[timocharis]

I hate to admit it, but I've spent more than a few idle moments wondering if there might be some way to make a 'stock' Dr1 cowl for the thing. Gotta have those two holes in the front, ya know?

Meanwhile, though, having too much fun flying it to worry much. Nobody who has seen it has any doubt about what it's modeling!


Dave North

[flypaper 2]

Yesterday I was showing a buddy these violent outside snaps when the motor flew off taking my precision, high tech cowl with it.:D Mounting bracket was still on the firewall. Not a very good setup the way it's built. Just a round piece on the back of the motor fits into a hole in the bracket and a 4/40 setscrew in it but the thickness is only .070 thick. Only enough room for about two threads and stripped the thread out. Tapped out to 6/32 and filed a flat on the motor part. All is good again:p I wonder how many of the Little Screamers did this, as the motor has been in there for about a month.

[timocharis]

Gotta watch it on those snaps! I just discovered that my aileron horns were working loose and needed a bit more aggressive gluing. There must be some stresses involved when a plane can roll/snap this fast.

I had a little screamer, but it was the first commercial release with the aluminum motor mount (which worked fine). I eventually bought a couple of the newer mounts ... so I have one here to look at. My wall thickness calipers .087, but I'm assuming you just eyeballed yours.

This is the first I've heard of someone losing one through set screw failure, but that doesn't mean it hasn't happened. I no longer have my LS (a de Novo) though I liked it a lot -- the early ones had a dental-drill whine that really, really irritates me. Scott insists the lexan version does not, but until I see and hear one in action, I'm hands off (I think he's partly deaf or something). However, it's a powerful little sucker.

The mount is made of something fairly soft, so I guess I'm not overly surprised that the screw pulled out. Of course, it wouldn't hurt if there were a flat on the bearing holder (that the screw tightens onto). Or a ring. At least the motor would stay on... did you get the Twisted Triple Wire Curse without screwing them up?

(I'm idly thinking about plunking a Komodo 278 on mine for a flight, just to see what totally obscene over powering is like).


Dave North

[flypaper 2]

Hi Dave:
This Screamer has an aluminum motor mt. Bought in the middle of last summer. Measured with calipers ( was a machinist in one of my other lives:D ) This one has a wicked whine at about half throttle. Twisted the wiring up but not enough to hurt it before it came apart and came down by itself. Got tail heavy real quick. Looked like one of those Harrier landings with full up elevator.:p Flew it in the dome this morning with no problems.

[timocharis]

Oh hey, my bad for assuming! I was very nervous and careful about the setscrew on my LS aluminum mount -- but it never did come loose. I even went and bought some spare set screws, because I was sure I'd lose that little thing (but I never did).

I popped a prop off the other day (rubber band failure) at a clumsy moment and the plan fell on its wampus with no problems. Put on another prop and kept flying.

I also had a nasty nose-in a while back, with no ill effects. This is probably the most durable depron plane I've flown. I am starting to get dirty wingtips from landing slightly across the wind. Just like the real thing!


Dave North

[timocharis]

After getting a bunch of noise about the 20-turn 22.7mm lensrc motor at slofly.com, I got around to winding one (26awg). 2s 9x5 is pretty efficient and okay for pooching around, but 3s 8040 is not to be believed!

Flip loops under 3ft diameter, sustained waterfalls, and of course the roll rate is way too fast to see. Most interesting to me, the speed is such that you can indeed hold knife more or less indefinitely without too much trouble -- the limit is the size of the field and how good you are turning in knife.

(I did manage a short knife 2s, but it's much harder. The coupling is severe and complicated, and varies with speed. I have not yet managed to hold anything remotely resembling high-alpha knife. It just flops out).

After a hard session that I ended by 'walking the dog' about 150 yards to my car, the battery (340 Kokam 3s) was slightly warm and the motor was actually cool to the touch!

Dave North

[timocharis]

The floppy bowed wings were driving me nuts, and I finally realized I could probably slip a .125" carbon tube between the struts and through the fuse on the middle wing.

No problem! Just took a 1/8" drill bit and worked a couple of holes in the fuse, slipped the tube through and glued it in place. Now the wings are very stiff and flat.

Haven't tried flying it to see if it makes any difference in the handling -- the glue is still drying! But if you've already built yours and didn't put any carbon on the wings, this looks like a good "aftermarket" solution.


Dave North