Thread: Build Log A-7D Project
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Old Apr 01, 2011, 09:51 AM
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Rock On- Damon Atwood
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Fishers, Indiana
Joined Oct 2004
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Originally Posted by monkamarm2000 View Post
Awesome project! I would seriously consider 2fans of smaller size rather than one big one on this. You always follow the math and in doing so you know real world with single you can't get over 14cells, that's where esc's are at. So we go 14 x 3.8 - 52.3volts now max amps on best cells average to 140 for long life and lotta throttle if needed. So regardless of fan you now know you can only get a best of 7300watts on the taxing end of a single system. And big systems like that are peaky, even with abundant thrust efflux for nominal flight is there when punched and gone just below, on down to non existant even half. But 2fans of smaller diameter will make more total and have broader throttle envelope. Just a thought. Also 2fans get a efficiency boost for free'usially 13percent or more.

You are looking at this just like I am.

I don't want a system that needs 100% to take off, and 85% just to stay in the air. I think the loss of efficiency with the ducting will be made back up with the 2 motors.

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