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The right combination for the job....

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Old 01-29-2018, 05:57 AM
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Springbok Flyer
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Question The right combination for the job....

I am sure this question has been asked before - but I will appreciate some input. I am thinking about building a RV4 Sport Acrobatic plane which would normally use a 60cc gas engine. The plane will normally weigh around 16kgs (35lbs).

Which motor, esc and battery combination should I be looking at to have a nice positive flying plane and get around 6 minutes of enjoyment?

Thank you for your suggestions.

JanR
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Old 02-17-2018, 04:01 PM
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I'm no expert but I keep hearing 100 watts per pound is a general "get you in the ball park". 3500 watts is a big motor that will pull a lot of power from your batteries. I suspect you will be looking at least 10 or 12s (37 or 44.4 volts) propped to pull approx 75 or 95 amps.(note: this is a full throttle situation)

I see Hobby king offers a Turnigy Roto max (50cc gas engine equivalent) allegedly capable of 5300 watts...172kv. they say the max volts is 44.....and I have learned (the hard way) to not exceed the max volt spec, so you should go with 10s (37 volts) battery pack. so to get the desired 3500 watts you would need to prop this motor to pull approx 95 amps (this motor is rated for max 120 amps so you should be fine). ...This motor "un-loaded" should turn 6364 RPMs at full throttle (full 37 volts). loaded with a prop, at full throttle, static (plane held from moving), I would expect to see 85% less (I'm guessing) ...approx 5500 RPMs. Thats quite a bit slower than your typical gasoline engine, so you will need a little more pitch and more diameter (or more blades).. If you would like, I can speculate on a battery pack
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Old 02-19-2018, 02:06 PM
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Thank you for your suggestions. I have had some very good advice from Hacker in Germany too.

Cheers,

JanR
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