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Speed,Combat,Scale,Racing => Rat Racing and Team Racing => Topic started by: Motorman on July 07, 2015, 09:21:38 PM

Title: Foam Wing
Post by: Motorman on July 07, 2015, 09:21:38 PM

To you racing guys that have used foam wing construction, how did you mount the bellcrank? How did you hold the lead out guide on? How was the wing constructed did you use spars, leading edge, trailing edge, fully sheeted or just monokote?

Thanks,
MM

Title: Re: Foam Wing
Post by: bill bischoff on July 07, 2015, 11:29:02 PM

All the above. I have built AMA slow rat and super slow rat wings that have been fully sheeted, sheeted LE and TE and cap stripped to save some sheeting weight, and bare foam covered with silkspan then low-temp film. All had a 1" thick center rib with a T-shaped bellcrank platform through a slot in the rib. All had balsa block tips to hold the line guides. All had 1/8"x3/8" flat spruce spars. The bare foam wing had a hobby shop balsa LE and TE. The wings with sheeting had 1/2" square spruce LE's, shaped after installation, and no solid TE other than the sheeting.

The blue/yellow airplane has a bare foam (no sheeting) wing. It is a previous NATS winner. The other airplane was ultimately covered in iron-on film.

Title: Re: Foam Wing
Post by: Motorman on July 08, 2015, 08:49:33 AM

I know the combat guys use LE, TE and spars with no sheeting. Do you think you could go without spars and TE if you had a balsa LE and full sheeting?


Thanks,
MM

Title: Re: Foam Wing
Post by: Paul Smith on July 08, 2015, 11:31:17 AM

I always mounted the BC to the body, then added the foam cores.
There is a wood insert on the inboard tip to hold the leadouts.

My setup was just like the current F2d FTR's except the wing was all foam, not just the LE.

Title: Re: Foam Wing
Post by: bill bischoff on July 08, 2015, 04:25:47 PM

Quote from: Motorman on July 08, 2015, 08:49:33 AM

I know the combat guys use LE, TE and spars with no sheeting. Do you think you could go without spars and TE if you had a balsa LE and full sheeting?


Thanks,
MM

The record holding SSR, originally built by John McCollum as a Fox racer, is built that way. Personally, I'll take the weight penalty and keep using spars.

Title: Re: Foam Wing
Post by: Motorman on July 08, 2015, 06:12:20 PM

Good to know thanks. I want the push rod to come out on the outboard side. I was going to use a large balsa center rib, cut a slot in it and line the slot top and bottom with ply then drill through the whole thing for a 1/8" music wire bellcrank pin. The pin will be glued and the wing sheeting will hold it too.

MM

Title: Re: Foam Wing
Post by: Paul Smith on July 08, 2015, 07:29:00 PM

Full sheeting in lieu of spars is OK if you cut a big airfoil hole in the body.

If you butt the cores up against the body you need something (spars) to hold the halves together.

Title: Re: Foam Wing
Post by: bill bischoff on July 08, 2015, 09:39:59 PM

Quote from: Motorman on July 08, 2015, 06:12:20 PM

Good to know thanks. I want the push rod to come out on the outboard side. I was going to use a large balsa center rib, cut a slot in it and line the slot top and bottom with ply then drill through the whole thing for a 1/8" music wire bellcrank pin. The pin will be glued and the wing sheeting will hold it too.

MM

You could also use a 1/8" brass tube that is flush with the top and bottom of the wing (makes the wing easier to work on). Then, use a 3/32" music wire pin through the brass tube. The pin would protrude about 1/2" above and below the wing, and would be inletted into the outboard side of the fuselage. It will NEVER pull out.

Title: Re: Foam Wing
Post by: Motorman on July 14, 2015, 02:16:30 PM

I like what that one guy did by putting in a sheer web then fully sheeting and coring almost everything out. I think the lead outs would interfere with the sheer web for our size wing.

I wanted to put in an adjustable lead out guide but I'm afraid there won't be enough foam left to keep the clams puffed out.

MM