Simon Chaddock Posted September 3, 2012 Share Posted September 3, 2012 Some time ago I did some crude tests to find out the minimum power level my 60" Giant Dragon used in level flight. The answer came out at just about 3 amps from its 3000mAh 3s LiPo, say 33W. With high pressure squarely over the NW hence virtually no wind I decided to find out the hard way - fly 'power on' for as long as possible. Boring! It flew for 71 minutes before the ESC LVC reduced the power (but at such a low power settings it was only just detectable!) which if my sums are correct represents an average current of 2.54A. Given this is only 10% of the full power (sustained vertical) current it does show just how efficient ESCs and motors are even at very low power levels, So I have another plane than can exceed 1 hour duration. Quote Link to comment Share on other sites More sharing options...
Dave Bran Posted September 3, 2012 Share Posted September 3, 2012 With a plane I was using for a school club training 11/12 year olds, an 800mm span "Fik" converted chuck glider with EP, I was regularly getting 45 mins plus, and still able to loop at the end of it................ on a 800mAh 2S................ Quote Link to comment Share on other sites More sharing options...
PatMc Posted September 3, 2012 Share Posted September 3, 2012 I recently logged the power taken over a couple of aerobatic flights of my Druine Akrobat. Model weighs 1940g with 2650mAH 4s lipos, average current was 12.66A average power 199W, flight times were 10 & 11 minutes. The count down timer of my Tx is now set to 9 minutes which I find gives plenty of time to complete whatever I'm doing before landing. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted September 3, 2012 Author Share Posted September 3, 2012 PatMc It makes an interesting comparison. Your Akrobat power loading is almost exactly 0.1W/g. The Giant Dragon weighs 646g and used 28W on the endurance flight or 0.043W/g. Quote Link to comment Share on other sites More sharing options...
PatMc Posted September 4, 2012 Share Posted September 4, 2012 Simon, the Akrobat is relatively "draggy" with a semi scale bulky fuselage, semi-symetrical wings & gets thrown about quite a bit each flight. I'm sure that if flown gently at part throttle the flight time could be more than doubled without much bother. The power at full throttle is 242W/Kg (110W/lb) & IMO it's actually over-powered. Quote Link to comment Share on other sites More sharing options...
David Gilder Posted September 4, 2012 Share Posted September 4, 2012 I recently flew my Phoenix 2000 glider for 45 mins on a 2200mha 3cell 11.1v lipo and it went from 12.6v fully charged to 12.3v. !! I think I would get bored before the battery lost interest!!! Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted September 4, 2012 Author Share Posted September 4, 2012 PatMc What was of interest to me in the comparison was how close the two figures really are. As you say one is doing aerobatics the other is just very, very gentle cruising in what is basically a light weight powered glider yet the difference is only a bit over 2:1. The Wing Dragon uses just 20W/lb however still a bit to go to equal the man powered cross channel Gossamer Albatross that managed on 1.36W/lb. Edited By Simon Chaddock on 04/09/2012 15:12:11 Quote Link to comment Share on other sites More sharing options...
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