EDF flight duration

[wollins]

There are two things that stopped me from getting into EDF's for a looooong time. That god aweful whining noise and their lack of run time.  Now with the new multi blade fans we're getting some sweet "turbine like" sounds but there still seems to be that run time/flight duration failing!

I like at least a good 6 minute flight with my birds (even the fast ones) and it seems based on my research etc that run times with this class of planes (with its style of flying) ranges between three and five minutes on average. (with decent power to weight ratio of course)

In my flying (in general) I have a little formula that I use to calculate "projected" flight duration. It's based on certain parameters so it would really help me out if as many as you EDF guys as possible can give me the following info based on your current average setup. (or based on past setups)

1. Amp draw with a given setup
2. Flight time with that setup.
3. Batt capacity with that setup.

Based on my little formula, this will help me to calculate the average "WOT percentage" that is common in this class of flying, which will in turn help me with my setup!

Thanks!

Colin

[sihinch]

OK Colin, so my latest 64mm set-up is in my Tornado.  I run a 2200mAh 4S battery and get about 4 minutes.  The amp draw was around 53amps (I think), running a 60A ESC giving around 790 watts.

A similar set-up in my Phantom, again a 4S 2200mAh set-up with a Don's Wicked 4000kV motor in 64mm fan, will also give 4 mins. I think this is about 550 watts and 39 amps.

A Don's Wicked 4800kV motor in a 64mm fan, with a 3S 2200mAh in my F-18 will also give 4 mins. I think this is about 380 watts and 37 amps.

Are you starting to see a theme?

My Wemo 50mm set-up with 5400kV motor using 1300mAh 3S lipo gives me 4 mins. Current is approx. 24 amps and 260 watts.

My Dynam A-10 with 2 x 65mm EDF units, each with a 40A esc, will use a 3S 3000mAh lipo in about 4 mins. Not sure of power or current on this set-up.

So, I usually set the timer to 4 mins on any EDF.

[Ededge2002]

just for a joke my present set up in the Enigma is 4S 4000's.  motor run time is 45seconds and uses 2000mA in that period (there is NO partial throttle as its on a switch).  Ive been recomended that at high loads like these only 65% of pack should be used. The packs im using are older and im trying to be "nice" to them...  Yesterday I thermaled for 7.5minutes with little effort and blasted around to 12 minute total flight with just those 45seconds motor run lol. 

160amps average @40C   

[flying saucer]

Colin, it all depends on what type of Jets(s) you're planning to fly.

With 64-70mm park flyer size foamies, 5 min flight duration is absolutely doable. These are typically scale flyers in the range of 60-90mph, with most models utilizing a standard 5 blade fan unit.

If you're planning on going with 70-90mm composite jets, these require significantly more power and generally have a top speed over 120mph. I'm guessing you're already aware that high blade-count EDF units draw more amps, and to be honest with you, I've never heard of anyone getting a 6min flight time. However I wouldn't let that dissuade you, flying a sweet sounding high powered EDF for 3-4 mins isn't a short a time as it seems

PS I believe ED has a flight duration app on his phone, he can easily calculate flight times for you based on projected amp draw...

[Ededge2002]

Quote"PS I believe ED has a flight duration app on his phone, he can easily calculate flight times for you based on projected amp draw..."

Actualy it is calculated by taking a short flight and measuring the recharge value (mA) vs the time (average current) then calculating the amount of time you could fly baised on the packs capacity and % of the pack desired to be used.

Over 40C average loads should have the % of pack volume used lowered to 65% or so...  This will keep your packs happy!

[flying saucer]

Ok yours works a little differently, I was thinking it was similar to this:

http://www.rcgroups.com/forums/showthread.php?t=1732044