Wooden frame, with fabric and fiberglass resin

[parnold]

I've seen some different posts relating to similar concepts, some with aircraft fabric, etc. In my head, the problem I see me having, is that the fabric will shrink between the wooden spars, and the outer skin will be anything but smooth. Filling in to make a smooth outer skin would be a problem, and could easily add a lot of weight.

My "bright" idea, for ya'll to comment on....

Build the wooden frame, cover with material of your choice. For my concept, I would be using polyester resin as a stiffening agent, then actually covering with fiberglass cloth once I have a fairly rigid shell. So here's the fun part.

Wrap the fabric as tight as possble, and staple liberally to the frame. You would have to be prepared to do the entire shell at once which could be a real issue, but... take the exhaust side of a shop vac, and feed the hose into the shell, which would puff the fabric. By carefully regulating the amount of pressure in the shell, you might be able to get a fairly smooth and rounded shell this way. I imagine as you go, you would have to decrease the air supply, since the application of resin would be inhibiting the "leakage" of the fabric.

Ok, now please tell me your thoughts on what I am missing. I know it can't be this simple.

I always thought it would be neat to make a giant egg trailer, with the bottom cut off obviously, for aerodynamics and aesthetics.

[glassice]

I don't think you have to do all at once .Can you rotate the shell. If so pick a flat part then tape the rest up with 6 mil are heaver plastic and packing tape. then do 1 part at a time put the plastic on in panels then take one off at a time that way you don't have to wrap the whole trailer

[GPW]

Par , having built many (hundreds) stick and stringer model aircraft in the past , and helping a few people with their homebuilt full scale planes ... I rather like the look of a tight stretched fabric covering ... and they can be glossy smooth with the right paint , and quite attractive ...

And for complex compound curves , you can do the covering in many sections , instead of fighting a one piece covering job ... all comes out looking the same finished in the end ..
And you don't have to use expensive aircraft fabrics either, a simple light/smooth linen canvas should work just fine ... easy and cheap to repair too ...
Check out your local small plane airport for ideas ...

[parnold]

My fear is that when shrunk, or pulled really tight, the trailer would resemble a giant geodome, with lots of flat panels between all the spars, instead of a nice smooth and consistantly rounded form.

Am I wrong? If so, then my whole idea is kind of pointless.

[kennyrayandersen]

Also, your airflow requirement will change as you fill all of the voids in the fabric with the resin (of any kind). There are some guys down in TX building concrete houses by basically blowing up a big balloon, then shooting insulation on that followed up by some rebar and then shooting concrete on that. Similarly, you could make yourself a bag that you could inflate and then shoot chopped fiber on it – that might work.

You’d probably have more control though, to build some frames across the tear, and then run stringers fore and aft through notches in the frames (kind of like dirigible construction). You could stretch the fabric over that – there are ways of getting the wrinkles out. It may not be that cheap in the end, but might net a kind of cool-looking airstream-like tear.

[GPW]

For a more rounded form , use more stringers , closely spaced ... Check out an old Beechcraft Staggerwing ... beautifully rounded forms ....

[schaney]

If a smooth surface is your primary criteria, seems like you can't get away from the extra weight of some fairing compound. The closer together your stringer, the less filling there will be.

[GPW]

Check out these beauties ... fabric covered... http://www.google.com/images?client=saf ... CDgQsAQwAw

[kennyrayandersen]

I always thought it would be cool to build a replica of a Curtiss Jenny, but that would take years!

[GPW]

And lotsa' Bucks too .... Would be COOL eh !! TD much easier ... and cheaper ...

[audrizzle]

Hi All,

I am a newbie to the forum, but have seriously enjoyed lurking on the site. I'm an industrial design grad student, and I am presently designing and building an ultra-light pop-up travel trailer. I'm planning on using the skin-on-frame technique you all are talking about (though more similar to the Greenland style kayaks than the airplanes).

Have ya'll seen other people use this building technique? I would love to chat with them.

Also, I'm curious if anyone knows the best place to buy (used or new) a small (~4' x 6' or 4' x 8') utility trailers in southern New England or online?

Thanks!

Audrey

[kennyrayandersen]

something similar has been discussed. It might be especially cool if it folded down, else it will have to be just a bit structural to resist the highway (motorway) air loads. It can certainly be done, but it won't provide very good insulation like the typical foam and wood construction. It also won't be quite as robust, but it's certainly possible.

[vtx1029]

Have a look at how this experimental aircraft is being made.

Look a the fuselage is done
They build a form and tie foam to it and heat it a little to bend it then cover with fiberglass, flip it remove the form fiberglass the inside and post cure it... Could be a real nice way to make a TTT

http://pro-composites.com/FreedomProject/index.htm

[Juneaudave]

You might look at the construction techniques for these Geodesic Aerolite Boats. I've thought it would work well on a Runlite design.

[GPW]

Great site JDave!!!
Par' , this was what I'm seriously considering ... http://tnttt.com/album_ ... c_id=65819
You can make the walls as rounded as you want with "formers".. the closer the stringers , the smoother the look ... http://tnttt.com/album_ ... c_id=66568

This process should produce a Very Light TD , capable of withstanding the air loads of highway speed towing... planes built like this fly Much faster than we ever could tow ... No problem... Glassing it would make it very TOUGH!!! Probably not add that much weight if you were careful with the resin (the heavy part)...
Just like building a Big Fat canoe ... ... and you could probably pull this off pretty cheap too if you did your own wood cutting ...


Ps. I have a boat trailer in the yard just waiting for a project like this ...