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Oct 17, 2003, 03:52 PM
Thread OP

7 foot Ford Trimotor

Hi guys.

Look out, here I go with another construction diary. The victim this time is the 7 foot ws (2.1m) Ford Trimotor. Building it from Stu Richmond's plans in the May 1987 RCM. I like these plans because he designed it to weigh just 6 pounds and to fly on a single .40 engine. That's a wing loading of 16 oz/ft.

My Mods:
Three sp500 (7.2v) motors, dd, 8x5 props, each with its own esc and 7 cell pack. Could also go with a more powerful center motor, but I want to keep the props scale-looking.
Like the original, mine will have a nonremovable center wing panel. The outer wing panels will connect where the outbound motors are fitted. The wing joiner will require a much different main spar than shown on these plans. Main support for the landing gear will be from the wing and nacelle (like the original) rather than heavy bent piano wire bolted to the fuse bottom, as on the plans.
The plans just do not contain very much balsa. The main lightening will occur with the fuse box. Instead of heavy balsa sandwiches, I will use light stuff with lightening holes.
Markings will be same as #9206 in the Pensacola naval air museum.

Made zerox copies of the plans. Am now cutting out the 26 wing ribs, and figuring out the revised main spar as I go along.

Wish me luck. BTW since my last project I've gotten a better camera. No more fuzzy pics!

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Oct 17, 2003, 04:02 PM
Visitor from Reality
Gooid luck Warren! It's bound to be a good flier, and if I know Stu's structures, you'd have to use cement and oak slabs to make it much heavier!

Chris Golds, who writes a sort-of jets column in Q&EFI once described a technique for simulating corrugated alloy skinning and panel lines by drawing them onto a silver / alloy surface using a white marking pen! Chris is the master of illusion when it comes to model aircraft finishes that look stunning from about five feet and further away, might be worth looking the technique up.

Suspect I recall reading that Stu 'modelled' a rare Trimotor done in flat alloy?

it'll look a lot better for not having that single twostroke jug hanging out the right side of the nose too.


Oct 17, 2003, 04:58 PM
Registered User
vintage1's Avatar
Corrugations? how about plastering it with spackle and drawing a comb over the top. Whenever I am tiling, the tile cement comes out just like that....

Then spray

never mind. Crazy idea...
Oct 18, 2003, 02:54 PM
Lagopus lagopus
WillowPtarmigan's Avatar
Go for it! It would be cool to see an electric RC Ford Trimotor.
Oct 19, 2003, 12:08 PM
Supersonic Engineering
GordonTarling's Avatar
Corrugations? Like this, you mean? I've just covered the fuel tank of my Tiger Moth - just need to paint it now.
Oct 19, 2003, 12:21 PM
Registered User
Ian Easton's Avatar
Here's the one in San Diego.
Oct 19, 2003, 12:23 PM
Registered User
Ian Easton's Avatar
Oct 19, 2003, 12:25 PM
Registered User
Ian Easton's Avatar
One more....
Oct 20, 2003, 01:57 AM
Victim of gravity

Looks great! Please keep us up to date (with pics!) as you go along. Do you have the reference no of the plan- my RCMís donít go that far back.

Gordon: What method did you use to get such neat corrugations? To be honest, the lack of a workable method to create then is what has always kept me from modeling the Trimotor and the Ju 52.

Best of luck

Oct 20, 2003, 01:59 AM
Victim of gravity
PS: Do you have any more pictures of thr Trimotor?
Oct 20, 2003, 05:31 AM
Registered IGG Finland pilot
Hannu Vuorinen's Avatar

Gordon T, whats that corrugated material in your TM tank?
My friend is looking to start build Junkers 50 in around 2 meter size, and would definately be interested in different methods of
making corrugated surface.

Oct 20, 2003, 09:30 AM
Thread OP
Those are good pictures, Ian, that show off the simplicity of the Trimotor fuselage. The last picture shows the difficulty with the wing. It's thick in the middle, thin at the tips and flat across the top.

The RCM plans show a main spar that is one-piece, 1/4" wide and varies from 1" high in the middle to 1/8" at the wing tip. It is always half as high as the wing rib.

To make this wing easy to transport in 3 pieces, I will build an I-beam type spar from 3/8x3/16" spruce sticks and balsa webbing. It will be as high as the ribs. Each outer panel will have an extra 6" of spar that will be inserted into a "spar box" in the middle panel. This spar box will be just like the I-beam but will have 1/32 plywood glued to the outsides instead of balsa webbing in the middle.

I'll post a picture soon.

Regarding the corrugated covering material, I read that Titanic Airways sells it but it is fragile. Right now I am leaning towards a flat metal grey film and marker pen lines.

I also have a reproduction of the Trimotor's owners manual. When purchased, this plane arrived in four crates. The manual shows assembly, flight prep, etc. To join the middle and outer wing panels it says "This will require a boy or small man" to crawl inside. Did the FAA know about this?

Last edited by WarrenKriesel; Oct 20, 2003 at 09:36 AM.
Oct 20, 2003, 09:54 AM
Thread OP
Here's a picture from the Pensacola museum. Impossible to get a clear shot in there. My model will have these 1930 markings. You can also see where the outer panels join the middle wing. The middle panel has a metal lip that covers the joint gap. I will use that on my plane, too.

Oct 20, 2003, 01:49 PM
Mr Mootsie
Tim Jonas's Avatar
Oct 20, 2003, 07:17 PM
My girlfriend has this device that corrugates colored paper/card stock for arts and crafts use. It works somewhat like an old-time washing machine wringer, with a hand crank that draws the stock into and through the rollers. I saw it work just the other night and thought to myself what a cool device it might be for possibly making corrugated panels out of aluminum litho plate for aircraft that had such panels.
I have not tried it for this particular use since I don't have any projects coming that need it, but I'd be glad to furnish a picture and info on where she got it, if interested.


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