I'm new to building Spads!

I've managed to find a local supplier of correx here in the UK but the 8 x 4ft sheets are only 3mm in thickness. If I bond two layers together will this make it too heavy for small deltas etc.

Any advice appreciated!

I would think that the 3mm would work okay for you. When 4mm is called for, you might need to reinforce the 3mm a bit, but I would think you should be fine with just the 3mm. The nice thing about SPAD's is that you can always try and see what happens with little financial investment. SPAD's work great for the "trial and error" approach.

Good luck,

Are SPAD deltas normally made from 4mm correx or should is this be thicker - say 6mm?

what spad delta? airfoiled or not? i use 2 mil for my deltas, but they're airfoiled, and have a spar setup. I defenitely wouldn't use 2 pieces of 3 mil, thats gonna be really to heavy.

I agree with Crash. If you can't get a definitive answer here, go for it. I think the worse that will happen is you need to put some bamboo skewers or small dowels down every tenth flute or something to stiffen it up.

You do not need to bond it together. 3mm coroplast will work great for a .40 class sport plane, in fact Spad #1 was built entirely out of 3mm coroplast. The neat thing about 3mm coroplast is that 1/8" dowel is a perfect fit inside the flutes for stiffening the tail feathers and control surfaces. It is awesome for building wings, as it's easier to fold and glue than 4mm, yet almost as strong...and much stronger than 2mm.

Thanks for the advice lads it's very welcome.

This is OS .32 powered SPAD delta that I was planning on building where I believe 4mm correx has been used.

A 14 inch wide correx doubler is bonded to the underside and a 1/8th ply top base for engine and hardware.

Those fins look at least 1/3 too big. Compared to my ddust that is. May be its a "perspective" illusion though and doesn't matter as long as they aren't too small It's got a 46 on it and is 35" wide.

voyager_663rd,

Yours looks a fast, neat bird! How thick is the coroplast?

Btw, that's not my delta but one I spotted on a website. You may be right about the fins being too large?



This is the plan for it.......

4mm for the whole thing.

i've clocked it at 96 mph with an OS46FX and 9x9 APC but its heavy cuz I had to use 1/4" ply for the ribs. Penetrates well though so the I guess it's a good trade off. I would think if you use fins that big that flutter will be a major cause of its (maiden flight) crash. Mine are only 6 inches tall. Rock solid at speed. It will also fly quite sedately at full trim throttle (trim full on, throttle full back).

Great design modification that Tattoo came up with.

edit--> I just looked at your plans for it. I think (you can always try it) that the elevons are too big (mine are only 1 inch) and the fins are way too big. With my 1 inch elevons, I only have 1/4 inch up, 1/4 inch down. And I've still bent the "delta" part at the trailing edge just in front of the elevons going into high speed dive/pullouts.

Check out the spad site for the ddust plans and you'll find two size deltas--the one I used and one for the engine you have (the one I used I just scaled up to the 46 size). You'll find that my bird utilizes a "fold-over" design to construct the main body. Your design will fly (single sheet) as one of my buddies has built and flown one like that. His was an experiment. Mine was a proven performer.

Either works. Just either modify yours or use the other plan set.

Voyager_663rd

That's very useful info....thanks!