View Full Version : Kontronic suggestions
I have a Kontronic Fun 400-23 brushless motor and I have been using it until now on a wing 27oz. 11.1/1500 direct drive 6x3.5 prop.
I am making a 3d/sport plane should be about 22oz. fw. and now have 11.1/2100mah
I would like to hover and was wondering if anyone has any sugestions if I should put a gearbox on it or fly direct and if so which prop would you recomend?
09-21-2005, 08:19 PM
I threw some numbers into Motocalc. It looks like 2.5:1 to 3:1 geared would give you 175-225 watts input. The efficiency is lower at 2.5:1 than 3:1. I put in using a 12x6 apc eprop. At 22 oz.,that's 127 watts/lbs. with the 3:1 gearbox.
I'd look at the cobri g/b at http://www.e-flightline.com/. They are great to deal with.
I have a few Cobri gear boxes now and think they are awesome.
Thanks for doing the legwork. I think 200+ watts should be more than adequate to hover 22oz. Do you think I should go higher gear ratio (4:1) and smaller prop say 11x4.7?
09-22-2005, 10:56 PM
I thnk that if you wanted to go to a smaller prop, I'd go to a lower gear ratio like 2.3-2.4:1 to keep the current up around 20 amps. This seems to be a sweet spot for the efficiency of the -23 turn motor. Of course, I'd play around with props to tweek the setup. Remember, this are just estimates from Motocalc.
Well the plane ended up at around 27 oz. but it flew excellantly. Even in about 25mph winds 2 weeks ago in the north east.
I used the 3:1 gb from cobri and apc 12x6sf
I could not believe it flew or that I threw it up in that wind.
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