Mar 09, 2003, 11:58 PM
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Brentwood,TN
Joined Mar 2001
482 Posts
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scratch hand launch/discus
Wanted to try this hand launch bit so scratch built this bird this weekend. AUW with radio gear installed ready to be pitched is 3.7 oz.
wing span 39 inches
airfoil SA7036
wing: balsa build up with beam main spar/ D tubular reinforced with carbon tow. Solite covering.
fuselage is smallest wrapped tapered rod.
Aileron/elevator
Radio: Hitec Feather with hs55 in wing, and cs 10 for elevator stuck way out on the nose. Reciever battery is Kokam 145 lipoly.
Balance was not too bad. Yes, I did mount everything way out front, but it seems okay. Adding weight, ie ballast to front to balance just seems like a sin to any object trying to fly.
Flights: Honestly, hard to compare since this is a first, and I have only seen one other HLG. I think it is okay, but my initial throws only get it maybe 50 feet. I find it difficult to gage height. Ended up discus throwing it. No problems with throwing it hard except the wing would slip a little because of too few rubber bands. Tried at slope above my house and it flies great. Ailerons are very responsive. Need to fine tune. My aileron push rods are too flimsy (flutter on one of my heavy throws).
If I were to do it again, I would change to a thinner foil to decrease my drag. I think the wing is actually way over built and could easily tolerate a thinner foil. I also now need to figure out how to enclose the front end radio gear. I like having easy access to the gear, and would like some easy "shell" attachment to enclose the gear. Any ideas? Definitely would stick with the lipoly cell. Oh yeah, the aileron set up is not that clean on the bottom surface and I believe induces quite a bit of drag. Any building tips to make clean aileron hinge line? I would consider v-tail and dihedral next time. Small carbon wrapped tubes are absolutely amazing. I would use that component again in a heart beat. The composites are truly amazing materials.
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