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Speed,Combat,Scale,Racing => Scale Models => Topic started by: Tim Wescott on September 22, 2018, 01:39:51 PM

Title: Scale flight time / battery sizing
Post by: Tim Wescott on September 22, 2018, 01:39:51 PM
Building a profile Ercoupe.  I'm at the point of cutting wood for the fuselage and thinking of whether I want to go 'lectric.  Which means buying (and making room for) batteries.

How long does a typical scale flight last?

-> OR <- does anyone have size guidelines?  I suspect that "enough to make the CG right" will be plenty for a couple of flights, but I'm interested in hearing from anyone who does 'lectric scale.

Title: Re: Scale flight time / battery sizing
Post by: Chris McMillin on September 23, 2018, 10:27:48 PM
Fred should be able to help out here.
Chris...
Title: Re: Scale flight time / battery sizing
Post by: Tim Wescott on September 24, 2018, 08:14:18 AM
I priced out electric systems, and looked at my stash of engines, and (somewhat reluctantly) decided to go with a 40FP.

But I'd still be interested in the answer.
Title: Re: Scale flight time / battery sizing
Post by: Paul Smith on September 25, 2018, 06:18:12 PM
The FP-40 has always served me well.  Four ounces is plenty.  A scale flight takes less than five minutes, mostly at low throttle.
Title: Re: Scale flight time / battery sizing
Post by: Fred Cronenwett on October 06, 2018, 06:03:35 PM
With the new rules a scale flight could be as short has 10 level laps and landing or as long as the rules allow. On the B-29 I can typically get two contest flights out of 4000 Mah sized batteries. It all depends on what throttle setting you are at during cruise, if you cruise at 1/2 power it will go far. The only real way is to fly it and measure the flight times.

If you look at the battery dimensional sizes there is a small difference between a 3000 Mah and a 4000 Mah. I use the hobby king website to get a gauge on the dimensional size of the batteries once you know the voltage, either 3S or 4S. The more the Mah the bigger they are in overall size.

If you can build and then test you can go up or down on the Mah size. All of my future CL scale models are going to be electric, I still have some glow powered sport models.

Fred