Has anyone built or flown the design from "Fly RC" plans, circa New Year's '05, called "Horsefly"? It is a generic 1920's barnstormer for indoor electric power. 34 inch span, 485 square inches, 8 oz, GWS IPS-DX2BB motor, elevator/rudder. If you have flown one please tell about it. Also, mine, if and when, will have to fly out in the wind. I intend to double the number of ribs, use heavier and stronger stringer material, a serious spar (maybe a carbon fiber whatever spar), add ailerons and a stronger motor. Original airfoil is undercambered, wondering about a different airfoil. Estimated take-off weight one pound plus or minus a few ounces. I have a trainer ARF I have flown some, a scratch build that is nearly complete, and may try electric with this heavily modified biplane design. Looking for suggestions, commentary, ideas about the original "Horsefly" and my proposed changes to the design.
Charlie wrote in news: snipped-for-privacy@comcast.com:
I've got the plans, but I've never seen one in person. With that caveat -
I probably wouldn't resort to carbon fiber. The back of my envelope (which is pretty well covered with scribbles by now) says that even if the wing was cantilevered, a 1/8 x 1/2" medium balsa spar should be good to 8 Gs on that plane. I haven't checked to make sure that the wing really is at least 1/2" thick.
Uhh . . . if you intend to do aerobatics that need ailerons, then fine. Otherwise, you're going to add a fair amount of weight, complexity, and drag without much real benefit.
oh, definitely. I have a lot of fun with my IPS motors, but on a 16 ounce biplane, all you'd be able to do is taxi. If you want a drop-in replacement, though - there's a Feigao (Balsa Products stocks 'em) brushless motor that fits the IPS gearbox and should be good to about 10 oz thrust; ISTR it's about $70 including ESC and gearbox. It should give pretty nice performance, although not wild aerobatics.
If you're going brushed, the GWS 350 is a nice little motor.
If you've already picked out the motor etc, then just ignore this.
You know, I've never been wild about undercambered airfoils. Yeah, they generate a lot of lift, but they're draggy, hard to cover, and you can't put in a deep spar. Also, in my (limited) experience, they tend to have nasty stalls.
I'd be tempted to simply make the bottom of the airfoil flat.
Sounds about right.
"some?"
Well . . . if you don't have a lot of experience with building & flying, I'd suggest you build something simpler & more rugged. I've been making little sheet-balsa profile biplanes for the IPS and I've had a lot of fun with them. Not that I want to discourage real building, in these days of ARFs.
If you want double the power use the IPS motor BUT put it on a 3s LIPO pack and knock 20% off the prop size.
That puts it in a very efficient part of its curve. It woun't haul an
80z model straight up, but an A geared one on a 7x6 prop (normally flown with a 9x7) will certainly do a large loop from level flight and give you a top speed of over 25mph.
Don't make the model heavier, just give it more power to cope with wind. Ive got a 7oz one on 3s LIPO (B gears/8x6) that climbs at 45 degrees... its biggest problem is turbulence. A little bit of shear and its on its back.
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