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Old Oct 16, 2011, 09:30 AM
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The "pro" in procrastination
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Canada, ON, Kingston
Joined Mar 2004
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Fun Build 5 (?) Design - 51" Span Lancaster in Pink Foam or (gasp!) Depron

Hey Everyone,

I've been pretty scarce on these pages lately, mostly because we moved from Ottawa to Kingston this summer, and there's been a buttload of stuff to do. We're finally settling in, and although setting up my workshop hasn't yet floated to the top of the priority list, I think I finally have time for a little bit of hobbying.

John (jofrost) mentioned in the context of last year's Fun Build 4 that this year's theme might be multi-engined birds, so with that as inspiration, I've started thinking about what my entry might eventually be. I've wanted to try some of the foam-building techniques in Sparky's "Building with Foam" book for a while now, and foam seems like a lightweight way to build a smallish multi with a low enough wing loading so that it doesn't have to fly around a fighter speeds just to stay airborne. I don't know if John will allow foam in the next FB, but I'm going to give it a try.

In anticipation of FB 5 launching, and it having a multi-engined theme, I'm going to try designing and building a 1/24 scale foamie Lancaster for IPS motors. This scale puts the model at 51" wingspan, with 2.25 square feet of wing area, so I think that if I can keep the AUW to 22-23 ounces, I'll end up with a bird that should have scale flying characteristics, ie. slow and majestic. I honestly don't know if this can be done, but it'll sure be fun trying!

I Googled around to see if there were any plans available that might be useful, and as luck would have it, someone was selling a copy of the June 1987 Model Aviation article and plan of Dennis Norman's amazing 51" span rubber-powered Lancaster, so I snapped it up. Dennis' design is an engineering marvel, and the plan has a large number of formers for the fuselage, inner and outer nacelles. I'll be using them as cross-sections for my foam version. The wing uses cracked rib construction, however, so I'm going to be on my own in terms of finding a suitable airfoil.

So, on to the first of what I'm sure will be a million questions as I work up the design: can anyone suggest an airfoil for this model? I'm looking for a relatively thick airfoil (for scale appearance) that has good low speed lift and a gentle stall. Thanks in advance!

Steve
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Last edited by Steve85; Oct 21, 2011 at 01:38 PM.
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