Let's make a better FT3D!

rcfred

Member
My FT3D has had a good six years, but now the paper is delaminating from the foam board. The last time I flew it, the left side of the elevator stopped doing what the right side was doing, and I barely got the plane down in one piece. Time to make another one!

And while we're at it, might as well make some improvements...

My goal here is to improve the flight characteristics of the FT3D without making the model significantly harder to build. The community has learned a lot since the original FT3D plans were published, so there's a lot to draw on.

Here's some video of the current prototype:

And some photos:
IMG_6375.JPG

IMG_6380.JPG

Modifications I've made so far:
  • Made the tail 2 1/2 inches longer to improve tracking
  • Moved the wood parts of the wing to the top and bottom edge to make the wing stiffer
  • Thickened the ailerons to stop them from flexing
  • Stiffened up the connection between the two halves of the elevator
  • Replaced the turbolators with Twisted Hobbys-style wing tip devices
  • Closed up the big drag-inducing hole in the front of the fuselage and added a battery hatch on top
I have a bunch of cell phone photos from the build to unpack. I also have some hand-drawn plans to enter into the computer. More to come!
 

Brett_N

Well-known member
The elevator connection is the biggest thing. Where you not using the hatch on the original?

The last one I built I used a yardstick cut to measure for the wing and ran it as close to wingtip-to-wingtip as I could. IIRC that was flying with a 2228 motor and a 10x4.7 on a 40A ESC with 3S 1200

It's still one of the best 3D planes out there, and cheap for a trainer.
 

rcfred

Member
The elevator connection is the biggest thing. Where you not using the hatch on the original?

The last one I built I used a yardstick cut to measure for the wing and ran it as close to wingtip-to-wingtip as I could. IIRC that was flying with a 2228 motor and a 10x4.7 on a 40A ESC with 3S 1200

It's still one of the best 3D planes out there, and cheap for a trainer.

As a matter of fact I do have a battery hatch on my old FT3D; I added it the second time I rebuilt the nose. It sure made battery changes a lot easier.

My spar is a tapered foam core with bamboo strips on the top and bottom. Here's a cross-section of the wing:
IMG_6277.JPG


I used a birch joiner made from a Lowes paint stirrer to join the two halves of the spar:
IMG_6295.JPG

IMG_6297.JPG
 

rcfred

Member
To lengthen the fuselage, I printed out a copy of the plans and penciled in a new back edge:
IMG_6417.JPG

I was intending to add two inches, but the fuselage ended up 2.5 inches longer than my old FT3D. I'm not 100% certain, but it looks like the fuselage in the tiled plans is half an inch longer than the fuselage in the one-page plans.

Anyhow, an extra 2.5 inches of tail moment makes the plane track better. I'll probably crank that up to 3 on the next prototype.

To get the plane to balance out with the longer tail, I removed the paper from the insides of back 10 inches of the fuselage sides:
IMG_6191.JPG

I also moved the rudder and elevator servos forward by 3 1/2 inches. I'm using Du-Bro 2-56 control rods (https://store.flitetest.com/dubro-12-256-rod-w-nylon-kwiklink-5-dub184/p25509), and I haven't had any problems with them flexing.

I used box joints on the fuselage corners, and I cut the top as a separate piece. I used paper surgical tape to help join the top corners.

I added some foam doublers around the servos to hold them in place. Of course, I forgot to glue the doublers on before closing up the fuselage. So I had to install them into the fuselage after the fact using chopsticks:
IMG_6309.JPG


I added some foam cross-pieces where the joiner meets the fuse, so that there would be more surface area for the glue. I kept the original popsicle stick alignment pin, but I oriented it vertically instead of horizontally:
IMG_6299.JPG

IMG_6298.JPG
 

Merv

Site Moderator
Staff member
I’ve made several changes to the FT3D also. Larger rudder, elevator, wing and longer nose to get the correct CG.
 

rcfred

Member
It took me a few tries to develop a reproducible process for the wing. Here's the sequence of steps I used on the current prototype:
  1. Establish the leading edge crease. It's important to be precise here, or you'll end up with a twisted wing later on. I used a straightedge and a ballpoint pen.
    IMG_6227.JPG
  2. Remove the paper from the inside of the wing ahead of the spar. Leave the rest of the paper on so that you have something to hold onto while bending.
    IMG_6229.JPG

  3. Using the edge of the table, give the foam between the leading edge and the spar a curve.
    IMG_6234.JPG

    IMG_6235.JPG
  4. Remove the foam from the spar channels and cut the bamboo strips down to length. They should stick out about 1.5 inches on the long side of the wings.
    IMG_6237.JPG
  5. Remove the rest of the paper from the inside of the wing. Leave the paper on the back of the aileron. Then glue in the bamboo strips, along with the foam strip that was originally inside the channels. Weigh everything down while the glue dries.
    IMG_6239.JPG

    IMG_6240.JPG
  6. Once the glue is set, sand the foam strips flat with the rest of the foam in the wing. Note the strip of foam that keeps the trailing edges of the wing the right distance apart.
    IMG_6241.JPG
  7. Cut some foam to serve as a shear web. I'm using 3/4-inch expanded polystyrene that I pulled out of the recycle bin. On a thicker wing, you could make a tapered box out of foam board. Glue the entire spar together, using shims made from scrap foam to ensure that everything is straight. Do NOT glue the trailing edge of the wing at this point. It's very important that the center line of the spar be at a 90-degree angle to the tabletop.
    IMG_6242.JPG

    IMG_6243.JPG
  8. Open up the aileron joint, fold the aileron back so that glue doesn't get inside the hinge area, and glue the trailing edges of the wing together.
  9. Sand a bevel into the trailing edge of the aileron. The bevel went from 7/8 inch wide at the root to 3/4 inch wide at the tip. I removed the paper from the bevel area, did a rough cut with a razor blade, then sanded the remaining foam down with a piece of sandpaper glued to a scrap of wood. This photo was taken after the rough cut and before the sanding.
    IMG_6257.JPG
  10. Remove the rest of the paper from the inside of the aileron. Cut a 2-inch-or-so wide strip of foam to serve as the bottom half of the aileron. Bevel it the same way as in the previous step and remove the paper from the beveled side. Glue the 2-inch strip to the top half of the aileron. I used some paper surgical tape here both to hold the pieces together and to smooth out the gap after the glue dries.
    IMG_6260.JPG
    Once the glue has set, everything should line up straight.
    IMG_6262.JPG
  11. Sand a partial bevel onto another strip of scrap foam and gently press the beveled side in between the top and bottom of the aileron. Once you're satisfied with the fit, glue the beveled strip in place.
    IMG_6270.JPG

  12. Use a razor blade to trim off all the excess foam from the aileron, then do a final sanding of the edges.
    IMG_6275.JPG
The final result:
IMG_6380 (1).JPG
 

Merv

Site Moderator
Staff member
How much larger? I haven't tried changing the size of the wings or control surfaces yet myself.
My rudder is about 9" x 9.5" & elevator is about 6" x 14". I don't know how they compare to stock. I don't believe they are a lot larger. Each half of my wing is about 12" at root & 9" at tip by 20" wide, with a 2" aileron. I believe the wing is quite a bit larger than stock. I have found that my rudder & elevator take quite a bit of abuse, so I double them up. That is, I use 2 layers of FB for both. I leave the paper in the center and put bevel on both sides. You must cut the bevel BEFORE you glue the 2 layers together. This make the rudder & elevator much stronger.
 

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rcfred

Member
My rudder is about 9" x 9.5" & elevator is about 6" x 14". I don't know how they compare to stock. I don't believe they are a lot larger. Each half of my wing is about 12" at root & 9" at tip by 20" wide, with a 2" aileron. I believe the wing is quite a bit larger than stock. I have found that my rudder & elevator take quite a bit of abuse, so I double them up. That is, I use 2 layers of FB for both. I leave the paper in the center and put bevel on both sides. You must cut the bevel BEFORE you glue the 2 layers together. This make the rudder & elevator much stronger.

Thanks for the dimensions! I think I'll try increasing the wing area on the next prototype. How did you keep the two halves of your elevator going up and down at the same time? It looks like you have maybe a quarter inch of foam joining them at the center?

Here's what I did for my elevator joiner:
IMG_6192.JPG

Half a popsicle stick glued in an inch from the hinge line. It works better than stock, I think it can still be improved upon.

On a side note, I think the rudder and elevator are only parts of my old FT3D that *didn't* get damaged in a crash. I guess different people crash differently :)
 

Merv

Site Moderator
Staff member
How did you keep the two halves of your elevator going up and down at the same time? It looks like you have maybe a quarter inch of foam joining them at the center?
I use a torque rod. The two halves of the elevator are not connected with foam. There is actually a gap between the halves to accommodate the rudder. I use marker flag wire to make the torque rod. I
 

miraspen

Member
just wanted to add my 2 cents on this thread. Its one of my favorites planes to date. first i would always recommend a slow fly prop IMO. second i like the vortex generators, however i don't notice a difference n the flying. But people sure do like to ask about them or point them out. they really attract attention.

For the landing gear use doll rods instead of skewers(also for almost any ft design with removable wings use doll rods). I also like to use some thin ply(the same as i use for firewalls i think maybe like 3/32) put it on the bottom so the landing gear doesn't push through the foam.

For the spar use a paint stick. for the elevator problem(i do this on almost all FT models) just put a Popsicle stick evenly on that thin spot and then cut the slot a bit bigger on the rudder to accommodate the popsicle stick(use gorilla glue its lighter then hot glue on the tail).

Here's what i do for the whole battery and charging. I run esc and battery in the swappable pod. Once i have cog i strap it in tight. I use an xt-60 extension that way the plugs are under the canopy(coincidentally, the balance lead is also under the canopy for me with a 3s 2200, and the leads point towards the tail). This way i can just charge it at the field without even removing the battery. And, I can plug and unplug by just removing the canopy.

If you follow the technique they use for closing up the front on the FT mustang, it works good here and also very well for the FT spitfire. Paint the plane then use a sharpie to just drop on and fill in the cockpit. Last thing i can think off is there is a guy on here somewhere that simply made the ft3d 120%. It's just a bit bigger but its amazing too. He blew up the plane but the body is the same width as a regular swappable. i fly these all the time. ALL THE TIME. lol
 

rcfred

Member
Thanks for sharing, miraspen!

I've drawn up some rough plans for my current prototype; see the attachments to this post. I didn't draw any of the rectangular pieces, but those should be reasonably self-explanatory. Also, the canopy was unchanged, so I didn't bother to redraw that.

I'm working on v2.0, slowly.
 

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rcfred

Member
Update: I've been working on a version 2 of the fuselage. There are a few issues I've noticed with my current prototype that I'd like to fix:
  • The propeller tends to strike the ground when belly-landing ==> Raise the base of the tail to give more prop clearance
  • At low speeds, knife-edge flight requires pitching the nose up, which makes rolling harriers difficult ==> Add more side area
  • The front and rear hatches on my prototype are looking pretty ratty after a few dozen flights ==> Switch to a single, larger hatch with a better retention mechanism
Also, after watching the build video for the new FT P40, I thought I would add some curvy bits to the new fuselage.

The bottom 2/3 of the new fuselage is basically just a big rectangle:
IMG_6598.JPG


The top part was more difficult. I started with a mockup at a scale of 1 cm = 1 inch:
IMG_6596.JPG


Then I did a full-size mockup in posterboard:
IMG_6445.JPG


Then it was time to figure out how to make those pieces accurately in foam, without having access to a laser cutter. It took a few failed attempts to work out a repeatable process for the rear turtledeck...
IMG_6529.JPG


Here's the process I settled on in the end. First, I cut out the turtledeck as a rectangle, leaving triangular pieces attached to act as a handle when bending the bendy part:
IMG_6495.JPG


I got the bending started on the table edge...
IMG_6496.JPG


...and then I used the "handles" to do the rest of the bending. The handles got pretty beat up, but the bendy part stayed smooth.
IMG_6497.JPG


Still holding the component by the handles, I kept bending until the sides were the right distance apart:
IMG_6500.JPG
IMG_6501.JPG


Then I attached some masking tape to hold the bottom edge in place:
IMG_6502.JPG


Next I used a 3/8 inch round dowel to fine-tune the contours of the turtledeck and get everything straight and true:
IMG_6503.JPG

IMG_6504.JPG


Next I put on an oven mitt and ran the top over a heat gun to set the curve permanently:
IMG_6506.JPG


After some experimentation on scrap pieces I settled on high heat and low fan settings for the heat gun. After a minute or so of moving back and forth, the curve was set permanently and I could remove the masking tape:
IMG_6507.JPG


Then it was time to slice off the "handles":
IMG_6509.JPG

IMG_6510.JPG


Finally, I removed the foam from the 1/2-inch tabs that overlap the joint between fuselage and turtledeck:
IMG_6511.JPG


The removable hatch goes immediately in front of the turtledeck, so I needed a pair of identical formers to ensure the curved pieces would sit flush with each other. I traced the shape of the turtledeck onto some posterboard to make a template:
IMG_6512.JPG

IMG_6517.JPG


The bottom of the former is angled a bit and keys into a vertical slot in the fuselage:
IMG_6525.JPG

IMG_6526.JPG

I had originally planned to have three formers (you can see the slots in the photo above), but setting the curve of the foam with a heat gun let me get away with only the one. Here's a photo of the back section of the fuselage, dry-fit with no glue:
IMG_6527.JPG


This post is probably long enough for now. More to come!
 

n0ukf

New member
I'm far from trying 3D myself (still have to successfully solo even a trainer outside of a sim) but yesterday I started wondering if anyone had done a mini/baby 3D plane yet.
 

Merv

Site Moderator
Staff member
@rcfred, you have some good ideas. I struggle getting the wind incidence correct and getting symmetrical wing curve, hard to get the same on the top and bottom. Yours look perfect, how do you do it.
 

rcfred

Member
I'm far from trying 3D myself (still have to successfully solo even a trainer outside of a sim) but yesterday I started wondering if anyone had done a mini/baby 3D plane yet.
Foamboard is really too heavy for a 3D plane smaller than the FT3D -- you'll have to remove all the paper and add some carbon to build something light enough for 3D at the sub-30-inch wingspan size. It can definitely be done, but the resulting airframe won't crash well. For working on your 3D skills, you'd probably be better off getting one of the EPP foam kits from Twisted Hobbys or West Michigan Park Flyers. I saw one of the Twisted Hobbys 24-inch models at the field the other day. It was positively tiny, and it flew quite well. I believe it was this one: https://twistedhobbys.com/th-24-epp-mini-mxs-c-blue/
 

rcfred

Member
@rcfred, you have some good ideas. I struggle getting the wind incidence correct and getting symmetrical wing curve, hard to get the same on the top and bottom. Yours look perfect, how do you do it.
In my case, the trick is to build a series of progressively less crooked wings and learn from your past mistakes ;-)
Here's a quick list of rules I've learned to follow when building a wing:
  • Do not trust your plans to be accurate! Home printers tend to print print out plans that are slightly warped. On something the size of a wing, that can mean that the top half the of the wing is 2 or 3 millimeters longer than the bottom half. Before you start cutting, get out a ruler and measure the parts of the wing that are supposed to be the same length to ensure that they are actually the same length.
  • After cutting out a pair of wings, put the two pieces of foam board back-to-back and make sure that both wings are exactly the same shape. This is also a good time to verify that you have actually cut a left wing and a right wing, as opposed to two left wings...
  • Firmly establish the leading edge crease before doing any other shaping of the wing. For thin wings, this means carefully cutting a very symmetrical bevel. For thicker wings, this means going over the back side of the leading edge with a ballpoint pen and then folding along that crease (see the photo at the beginning of post #7 in this thread).
  • The Adams foam board has a natural waviness to it. If you're cutting a wing out with the waves running from root to tip, try to place the leading edge in the center of one of the "troughs". I forgot to follow this step on my current build for this thread, and it's added a good deal of unnecessary work to forming the wings.
  • In addition to the leading edge, there are two other crucial points that need to line up between the top and bottom halves of the wing. The first point to watch is the thickest point in the airfoil profile. The second point is the aileron hinge line on the top half and the end of the bottom half. Before shaping the wing, get out a ruler and make sure that both of these pairs of points are exactly the same distance from the leading edge everywhere -- top and bottom, left and right. Mark the thickest point in the airfoil on the sides of the foam board with a felt-tip pen so that you can see its location when folding the wing.
  • Use white Gorilla Glue to close up the two halves of the wing. Three reasons for this: (1) It gives you enough working time to ensure that the thickest points of the top and bottom are precisely aligned with each other before clamping everything in place. (2) The joint at the back of the wing is going to have a gap, and Gorilla Glue expands to fill that gap. (3) If you mess up and need to cut the two halves of the wing apart, it's much easier to cut a layer of white Gorilla Glue than just about any other type of adhesive.
 

n0ukf

New member
In my case, the trick is to build a series of progressively less crooked wings and learn from your past mistakes ;-)
Here's a quick list of rules I've learned to follow when building a wing:
  • Do not trust your plans to be accurate! Home printers tend to print print out plans that are slightly warped. On something the size of a wing, that can mean that the top half the of the wing is 2 or 3 millimeters longer than the bottom half. Before you start cutting, get out a ruler and measure the parts of the wing that are supposed to be the same length to ensure that they are actually the same length.
I found this when I tiled my Simple Cub plans together, lines on one sheet didn't quite line up with those on its neighbor, mostly on the long edge, printing in portrait orientation.
 

rcfred

Member
Update: For the front turtledeck, I used a piece of foam cut in this shape:
IMG_6531.JPG

Similar to the front turtledeck on the FT P40, this piece needs a beveled inner edge to sit flush with the rest of the fuselage. I started by removing the paper from just the beveled part. Then I rough-cut a tapered bevel and cleaned it up with a sanding block:
IMG_6533.JPG

IMG_6534.JPG

Next it was time to peel the paper off the center.
IMG_6535.JPG


Oops! I put the bevels in the wrong direction :-\ Let's try that again...

IMG_6537.JPG

IMG_6539.JPG

IMG_6540.JPG

IMG_6541.JPG

IMG_6542.JPG


That's more like it. Next I gave the front turtledeck a partial curve on the edge of the table:
IMG_6543.JPG


Then I did the rest of the shaping the same way as the rear turtledeck: Mold the paper into the right dimensions, tape it in position with some masking tape, then use a heat gun to make the curved contour permanent. Here's the final result:

IMG_6545.JPG


To avoid needing a second set of formers, I'm making this piece do double duty. The front 4 inches is part of the fuselage, while the back part is part of the removable hatch.
IMG_6546.JPG


The base of the hatch is a foam rectangle. I used the curved front piece of the hatch as a template and marked some cutouts to join the base with the front piece:
IMG_6548.JPG

IMG_6550.JPG


Then I hot-glued the two pieces together, folded over the overhanging paper tab from the curved part, and hot-glued the tab down to protect the foamboard from delaminating:
IMG_6551.JPG

IMG_6552.JPG


Next I cut a coffee stirrer into 5 pieces and hot-glued them to the front of the hatch to hold the front of the hatch down:
IMG_6554.JPG

I glued a layer of paper to the inside of the front turtledeck to help reduce wear from contact with pieces of coffee stirrer:
IMG_6556.JPG


The next part of the hatch was the rear former, which I traced from the same template I used for the rear turtledeck, minus the tabs on the sides:
IMG_6558.JPG


After gluing the former in place, I realized that it needed some notches to sit on top of the fuselage, so I cut it back off the base of the canopy and added those:
IMG_6560.JPG


Then I glued the former onto the base a second time, using the former for the rear turtledeck as a jig to determine the angle at which to glue the canopy former:
IMG_6561.JPG


At this point, the former was only tacked in place. I removed the canopy and cut some gussets out of scrap foam to secure the former more firmly:

IMG_6562.JPG


My plan is to run a barbecue skewer through these gussets to hold the hatch in place. Looking at the current state of things, I'm not sure there's going to be enough clearance for the ailerons, though. If I can't make the skewer work, I'll add some magnets.

Next I cut the back half of the canopy. I started with a rectangle with the paper removed from one side:
IMG_6564.JPG

IMG_6565.JPG

Then I hot-glued the rectangle to the former and the bottom of the hatch:
IMG_6569.JPG

I had deliberately let the curved foam piece overhang the former. I trimmed the excess foam to make the rear of the cockpit be flush with the former:
IMG_6570.JPG

IMG_6571.JPG


Here's how the hatch looked at this point:
IMG_6572.JPG

By the way, in the background of that photo you can see the "draft" hatch I made earlier to work out the kinks in the build process.

I think that on the next prototype I'll probably make the back piece slope up towards the front instead of going straight across; but for now this version will do.

The final component of the hatch is the front half of the canopy. This piece needs to be custom-fitted. I started by cutting out a half-circle from some thin paper.
IMG_6575.JPG

Then I taped the paper semicircle to the hatch, held the hatch up to the light, and traced where the paper met the edges of the hatch:

IMG_6576.JPG

IMG_6578.JPG

IMG_6579.JPG

IMG_6580.JPG


This process left me with a paper template, which I then traced onto some foamboard:
IMG_6581.JPG


I removed the foam from the flaps that go under the base of the hatch and sanded a bevel into the front of the canopy:
IMG_6583.JPG


Then I removed the remaining paper from the inside of the canopy front and test-fit the canopy front in place. I needed to remove a bit more foam to make it fit snugly:
IMG_6585.JPG


Then I hot-glued that component to the rest of the hatch.

Here's a photo of the fuselage components I've built so far, dry-fit together:
IMG_6587.JPG
 

rcfred

Member
For version 2 of the wing, I added 2 inches to the tip chord and 1 inch to the root chord.
IMG_6606.JPG


This should hopefully decrease the wing loading and make the transition from harrier to knife edge go more smoothly. I just barely fit two wings onto a single piece of foam board:
IMG_6605.JPG


I've also switched to carbon fiber for the spar caps. It turns out that carbon tow (the stuff that carbon fiber cloth is woven from) is surprisingly easy to source in small quantities. I ordered 30 feet from eBay for about $6 including shipping -- 20 cents a foot. Of course you'll need some laminating epoxy to work with carbon tow, but I happen to have some lying around.

As before, I set the leading edge and removed strips of foam where the spar caps would go:
IMG_6608.JPG


Then I measured out some carbon tow to fill those channels, with some overhang to soak up any excess resin:
IMG_6610.JPG


I'm using 24k carbon tow. "24k" means that the tow is made up of approximately 24,000 very, very thin strands of carbon fiber. The channel that I used for this pair of wings was 1/4 inch wide, and the 24k tow needed to be folded over at the edges to fit. Next time I'll cut the channels a bit wider.

Once the carbon tow was seated in the bottom of the groove, I test-fit the foam strips that would cover up the spar caps. I also laid out some plastic wrap underneath the wing so as not to epoxy the wing to the cutting mat. It's important to have everything ready to go before you start applying resin.
IMG_6614.JPG

Note the foam extensions at the bottom of the above photo. The end of each spar cap needs to extend about 1 1/4 inches into the fuselage.

Next I mixed up about 5 grams of resin:
IMG_6615.JPG


I'm using U.S. Composites 635 thin resin with the medium hardener (http://www.uscomposites.com/epoxy.html). This epoxy is a great wood finish and a decent laminating resin. It's also very inexpensive -- cheaper than polyurethane varnish once you account for its 100% solids content. I ended up using about 3.8 grams on the first wing, and that amount just barely wet out the carbon. On the second wing I used closer to 4.2 grams and got better coverage. Sorry, no photos of applying the resin; I was wearing gloves. I used a coffee stirrer to put down one drop of resin at a time, alternating between top and bottom so as to even out the amount of resin for each spar cap. When the surface of the carbon looked uniformly shiny, I put in the precut foam strips, laid some more plastic wrap on top, and weighed everything down while the epoxy set:

IMG_6619.JPG


Here's what the wing looked like once the resin had partially cured:

IMG_6620.JPG


Next I peeled the paper off most of the inside of the wing:
IMG_6621.JPG


Some of the excess resin had soaked into the paper, and that actually made it easier to remove because the epoxy-impregnated paper is stiffer than the foam.

On version 1 of the wing, the foam shear web was tapered, and the spacer at the back of the wing was of of fixed height. On version 2 of the wing, the shear web ended up being 19mm thick all the way across, while the spacer tapers from root to tip.

IMG_6627 (1).JPG


I made the tapered strip from two strips of foam board, one that tapered from 8 to 6mm and a second that went from 10 to 8mm:
IMG_6623.JPG


I used my last few drops of Foam-Tac to glue these strips together in pairs, one for each wing:

IMG_6624.JPG


When I first tried to close up the wing, the front part ended up with some unintentional camber:
IMG_6628.JPG


The foam board had a series of ripples running along it lengthwise from the manufacturing process, and it decided that it would bend more where there was a trough in the ripples. And every time I molded it into the shape it was supposed to have, it would slowly return to the cambered shape. I ended up molding it into shape once so that I could glue on the shear web; then molding it again using a 1/2-inch dowel,
IMG_6630.JPG

Finally I set the leading edge shape with a heat gun and got it roughly symmetrical.
IMG_6657.JPG


On the other wing I spent a few minutes more working the front half of the wing on the table edge, and I was able to avoid the dowel-and-heat-gun routine:
IMG_6672.JPG


I improved the trailing edge on this iteration of the wings. I cut the bottom skin of the aileron an extra 3/4 inch wide; removed the foam from the extra part; and used the paper as a backing for the tapered section of the upper aileron skin:

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Using this method instead of paper tape gives a nice sharp trailing edge.

I cracked open a fresh bottle of Foam-Tac and used it to glue the paper to the foam. About 5 minutes later, I glued the remainder of the aileron skin down using white Gorilla Glue, because:
a) Gorilla Glue expands to fill gaps; and
b) I'm not made of money.
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