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Old Jan 19, 2012, 12:12 PM
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Kool Kats Fly RC!! AMA 30462
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United States, CA, Baywood-Los Osos
Joined Feb 2009
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Quote:
Originally Posted by lhb009 View Post
I am in the process of building a 5' EDF flying wing(EPP foam). I have built about 30 pusher flying wings, but I have never built or flown EDF models. What key differences would you point out? In addition to my flying wings I have built, more than a dozen balsa buildup, gas/Electric/sailplanes.

I plan to make it 5' span, weigh less than 4 lb, dual EDF units on the top rear where the prop normally would be. How big of EDF units should I start with? I was considering 60-90mm units. I will be flying it with a DX6i, with HS 82mg servos. Is there anything else I should know prior to buying electronics?
Had to think about it for awhile, but here on some things to consider. Edf's are run at very high rpm, (higher than the typical pusher wing), which usually require high-discharge battery packs, and due to their ability to draw high amperage on 3S, two good esc's. I would think that two 64mm-70mm fans with 3000-4000kv motors, two good quality 40-60A esc's, (not cheapies; they usually can't handle high amps and high rpm's at the same time); genuine Hobbywing and/or Castle esc's with adjustable timing should be on your list. With twin edf's you will need a lipo for each unit, so that should be taken into account also. Running a single lipo could work, but capacity will be an issue as edf's are amp hogs, (especially on 3S). An edf takes time to spool up to flying speed and you will need enough thrust to get it moving quickly if hand launching, so AUW will be an important consideration. I'm sure there have been other edf wings built, but the only one I can remember off hand is the GP Miglet which has the fan built into the wing, but if you were going to mount your fans on top of the wing, aerodynamic drag might become an issue, (just postulating here). I have two edf's, and I love them, but I don't have that much experience with pusher wings, so maybe someone else can pipe in with some better advice than I; good luck!

Edf's are great fun, I hope your idea comes to fruition and you end up with a great flying wing.

Sonny
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