I know I'm mad but that's what this section is for right?

[TTMR]

I had this crazy idea today on my way to lunch. Given the simple construction techniques used with the FT and other foam board planes I want to try making one out of .020 aluminum sheet. Obviously the control surfaces would need real hinges and the tail feathers would have to be rethought but it could make a cool looking FT mustang that might even fly with enough motor on it.

 

[engineer]

Approved! I wanna see pictures and plans on my desk before noon!

In all seriousness though, you might have to make foam board formers to support the wing shape and fuse.

 

[TTMR]

How much foam is actually in one of these things? Looks like .020 6061 is just over 1/4lb a square foot

 

[rcspaceflight]

According to the FT Store, "Weight - 16 oz (453 g) without battery" (for the FT Mustang). Although, I think weight of foam board vs. weight of aluminum is a better way to look at it. If it's "too heavy", just add more power and it'll fly.

How are you going to build it? Build one out of foam, make a mold of it, cast it in plaster of paris, then bang the aluminum around the plaster Mustang? I know it sounds complicated, but it would be very easy to make more.

 

[TTMR]

Use the plans, tweaked as needed then bend and rivet

 

[TTMR]

So to expand on this idea, control surfaces and stabilizers could be made from a single piece of aluminum, folded over sharply at the end opposite the hinge then riveted together sandwiching a small piano hinge.

So far as power goes I like the idea of a swappable pod. This could easily be built up as an aluminum box as well, then slid inside the fuselage and secured with four screws and nut plates. For the actual go portion I have a 30 size glow engine laying around that has never been run. This could be a good candidate for it.

I'm thinking I'd need to jig in a little washout for the wing tips as I don't think that sheetmetal will like the undercamber structure used in these planes.

Next question, how many sheets are in a mustang and what are the dimensions of a sheet of foam board. I may just order a sheet of aluminum while I'm here at work.

 

[quorneng]

TTMR
There is a danger that you will embark on the upward power/weight spiral and end up with something that would be at best difficult to fly.
At the size of the FT Mustang the ally would have to be a great deal thinner than 0.020 to give a reasonable strength to weight.

Covering a foam structure with ally foil would be about right.

I shall watch with interest.

 

[TTMR]

I am well aware of the weight danger, and if it turns out too heavy to fly I'll just have had a fun project and an interesting model. This is one reason I'm leaning towards glow power. Still can't beat the power density of a gas tank!

 

[rcspaceflight]

Even if you get it at a flyable weight, you may have spent so much time building it that you'd rather have it on display than fly. ... But if you're anything like me you'll fly it no matter what. lol.

 

[SnowRocker88]

Why not just aluminum-tape a foam model? It's been done and documented on the forums here and would achieve the same thing...it would LOOK aluminum.

 

[RAM]

Will this affect the antenna? Even outside the plane, won't one direction be blocked by the aluminum?

 

[TTMR]

I'd probably use a satilite reciver one with the antenna out the top one out the bottom. One will be pointed the right way.

 

[TTMR]

4x6' piece of aluminum, a 1/2" square tube for a spar and some piano hinge is on the way! Hope to have it Tuesday, and if so I hope to have the parts cut out by the following day.

Now do I just get lazy and use all blind rivets or do use solid ones wherever I can get a bucking bar?

 

[TTMR]

Reviewing the plans for the FT mustang it looks like the two horizontal stabilizer and elevator halves will have to be built separately. As such I need a way to join them together. As such I'm thinking that I can just run a spar down the stabilizer. If I do it right and keep one side flat the other should slightly curve for an airfoil shape the same way the wings are built. That should work out peachy, just have to ensure that the flat side faces up when installed.

 

[rcspaceflight]

You don't want to TIG weld your plane? lol.

 

[TTMR]

I'm not good enough on TIG to do .020 and I can't afford a HF machine anyway. I scrapped together to get my MIG lol. Besides it would be really hard to keep it true.

Nah, I'm a professional riveter, but only an amateur welder.

 

[TTMR]

CURSE MY FAT FINGERS!

I typed in the conformation code on my card wrong and due to the holiday they couldn't call me to fix it until today.

So it ships today and day after tomorrow I should have it.

 

[rcspaceflight]

*Curses your fat fingers*

I hope that helps!

 

[finnen]

Here's another madman =)
http://www.rcflyg.se/forum/showthread.php/35002-MFI-9-skala-1-2-5

Swedish, but I guess you get the idea. I wonder what your weight will be. If i calculate correctly your alu is 0,5mm thick, and this guy uses 0,3mm for his 3m span plane

 

[TTMR]

That is cool, wish I could read it!

I love how he built it up using the same semimonocoque construction as a full scale. Mine will be fully monocoque with the exception of the wing spar that structurally, I'm sure I could do with out but I need the spacer for the airfoil.