Enlarge GP profile P 38 to 80 in !!
01-12-2006, 11:50 PM
#2
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RE: Enlarge GP profile P 38 to 80 in !!
Shouldn't be a problem although some of the wood sizes may scale up larger than they need to be. If it stays in the 12 to 13 lb range anything from a couple of 70 two strokes or 90 four strokes should give it plenty of power even on one engine.
ORIGINAL: Check6
Thinking of enlarging a Great Planes Profile P 38 to 80 in. or a little larger. Any ideas on this? What size engines.
Thanks,
Fred
Thinking of enlarging a Great Planes Profile P 38 to 80 in. or a little larger. Any ideas on this? What size engines.
Thanks,
Fred
01-13-2006, 06:49 PM
#3
RE: Enlarge GP profile P 38 to 80 in !!
The problem with any profile is a weakness right behind the wing and the larger they are the more prone they are to break there. The Paul Swanson designs and the Ohio Model Planes kits have either a fiberglass rod or carbon fiber tube down the fuselage for strength. Their large, .91 size Fusion has a sheeted foam fuselage reinforced with twin carbon fiber I-beams. You might want to take a look at their construction techniques.
A friend of mine has the Profile-38 and he broke his first one behind the wing. He strengthened his second one. I would recommend that you check the OMP and Swanson sites to see how their profiles are built before starting on one that large.
A friend of mine has the Profile-38 and he broke his first one behind the wing. He strengthened his second one. I would recommend that you check the OMP and Swanson sites to see how their profiles are built before starting on one that large.
