speedadict

I want to build an obscure WW2 Warbird from scratch but don't know how to create the canopy. How does one make the clear canopy?

LA7flier

My Feedback: (1)

in order to vacu-form a canopy, you'll have to make a plug or you can build the frame and glue clear sheets to it...either method is very laborious. Depending upon the plane, you can choose.. For the plug method, you need to shape a piece of balsa to the exact shape less the thickness of the canopy. You'll then want to glass the plug and sand it to a mirror like finish...this takes along time. Once done, you can pull a canopy. The frame method requires you to structurally build the frame and attach acetate sheets to the frame. The problem with this method is that vibration will loosen the sheets of acetate

speedadict

Thanks LA7Flier. Tell me about your LA7! That is one of my all time favorite WW2 Warbirds and I don't see many! I love the Russian stuff but it is hard to find in RC. Heritage RC is going to be comming out with a Yak 9 soon! I want to build a .40 or .60 size Baulton Paul Defiant from scratch.

Jaymom

Years ago when my son first got into R/C cars I decided that I wanted to make my own car bodys since the local Hobby Shop charged around $20 each for them.

The next body we bought for one of his cars got duplicated before it got painted ! I filled the new body with Plaster of Paris and let it harden. First attempt failed because I allowed air bubbles on the body surface. After cleaning everything out and polishing the inside of the body I filled it again. This time it came out perfectly. Now I had a mold in the exact shape of the car right down to the headlights.

I then built a box, enclosing all sides, top and bottom. On the top I drilled small holes just a little bigger than the mold itself the exact sizes I don't remember now but around 1/8" holes.
I then drilled a hole on one end of the box that was just big enough for my wife's vacuum cleaner hose to fit into. I then drove a nail in all four corners on the top of the box, cutting off the nail heads after nailing.

Then I took a 1" by 1" piece of wood and made it the same shape and size as the top of the box's outer edges. Drilled a hole in all four corners so that it would slip right over the nails. ( Holes have to be made about twice as big as the size of the nails so that the frame slips over the nails QUITE LOOSELY) Then I made another one exactly like the first.

Now drill a small hole thru both frames in both ends directly in the middle. Find 2 screws just a bit larger than the holes and set them aside for the time being.

Find yourself a piece of Lexan at your local hobby shop. Cut it just a little bit bigger than the frames you just made, place the Lexan between the frames and place your drill bit in the screw holes on the frame ends and drill thru the Lexan. Now place the screws in the holes and screw the two frames together fairly tight.

You now have a piece of Lexan securely held between the two 1x1" frames. Now drill out the four corners thru the Lexan so that the four corners will slip right over the four nails on the box QUITE LOOSELY.

Plug your vacuum cleaner in a wall outlet. Take the hose and insert the metal/plastic end in the hole you drilled in the end of the box. Place the Plaster of Paris mold on the box so that some holes can be seen all around the base of it.

Now, while your wife is gone shopping and doesn't know what you are doing to her oven......

Preheat the oven to around 400 degrees. Open the oven door and place the frame work holding the Plexan in the oven. It doesn't take long so watch it thru the oven door window. When you see the heat causing the Plexan to rise and flop around a little its ready. Open the oven door and as quickly as possible place the Lexan and frame work over the 4 nails of the box. Immediately turn on the vacuum cleaner.

You now have a perfectly formed R/C car body. Trim in out and paint it.

The time it takes to get the Plexan from the oven until the time you click on the vacuum cleaner is very important. Which is why the frame must slide down over the nails QUITE EASILY. If the Lexan cools too much before you turn on the vacuum cleaner it won't come out good at all. If this happens leave the vacuum cleaner alone and put the framework right back in the oven and heat the Lexan again.

This principal works just as good with airplane canopy's. Made a bunch of them too. If you don't have the canopy to copy then carve one out of a piece of wood and use that for the mold. I used to carve lines across them to imitate those of real canopys. Just remember that the finish on the mold will be very everdent in the finished product. Carve your initials in the mold and it comes out in the canopy.

Word of caution though......Those frames come out of the oven quite hot !

If I've forgotten anything let me know.

LA7flier

My Feedback: (1)

Wow, where to start...I've built and flown 2 from the Don Smith plan. Both powered with a 3W 48 twin electronic ignition. The second flew at the last year's Scale Master Championships in Oregon. Unfortunately, it crashed after a massive radio failure. The first died after a midair with a trainer. The plane flew very well considering the relatively short wing span (80 inches) and a 24 pound flying weight. It was very easy to land once you understood it needed lots of speed.. I typically brought it in at half throttle to about 20 feet above the runway threshold and choped power...from there, it slowed down alot and gently touhed down on the mains...neat airplane and very unique. Both mine had functional leading edge slats that popped when the gear was extended.

speedadict

Hey thanks for taking the time to type all that!

Tamecat

Hey Jaymom,

Boy does that bring back memories. I remember when I made my first (and only) vac former. Made over twenty canopies with it. The only thing that I see that may be a potential problem is the heat.
I had to keep the temperture down between 275 to 350. If it gets hotter than that, I found that I got airbubbles in the plastic. As one guy told me at the Toledo show, Your not baking a cake, just trying to get the plastic a little soft

Jaymom

Its been quite a while since I made a canopy myself but I do remember it being quite a lot of fun. I loved watching it take shape when I flipped that vacuum cleaner on. LOL

As for the temp. I really can't remember how high the temp was, we had an old stove with a temp. gauge that was probably way off anyway. I made my first canopy for a elec. glider of which numerous were made due to the fact I kept loosing them in flight.

But it was fun. Good memories.