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Wattage figures on Pitts

Old 10-09-2011, 03:30 PM
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woodfit
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Default Wattage figures on Pitts

Hi Guys

Finally got my watt meter coupled up to my Pitts with the new lipo's, it appears to have a stonking 2340 watts at full power with a 6s and 2s in series both 5000MaH and both at 40c, question is will she fly ?? Oh and the rpm without the prop was 7800 rpm good or bad?

Last edited by woodfit; 10-09-2011 at 03:56 PM. Reason: Wrong info
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Old 10-16-2011, 09:51 PM
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payne9999
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How much does she weigh? Size and pitch of prop? I am assuming it is converted from a gas powered design. If so, what was the original required displacement?

Dave
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Old 10-17-2011, 05:40 AM
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Wildflyer
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Rule of thumb would say 2340 watts should fly 11 1/2 lbs in 3D maneuvers, and 23 lbs in aerobatic flight, even more in normal flight.

BUT these are all assuming you have the plane properly setup with the correct prop and getting the rpm you should have. At 8s you could put 2340 into too small a prop and not get airborne. It seems at 8s your motor will have to have a very low KV.

Give us more information, and we can be more help.
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Old 10-22-2011, 06:39 AM
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Bill G
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Originally Posted by woodfit View Post
Hi Guys

Finally got my watt meter coupled up to my Pitts with the new lipo's, it appears to have a stonking 2340 watts at full power with a 6s and 2s in series both 5000MaH and both at 40c, question is will she fly ?? Oh and the rpm without the prop was 7800 rpm good or bad?
I first read this and thought: A Wattage Pitts with 2340 watts is just a bit out of hand.
I heard that they had somewhat mediocre performance on the oem setup, but that's just a bit overkill.
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Old 11-09-2011, 12:12 AM
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CT4
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What every one forgets is that all watt meters give you watts in not watts out. 2340 watts is way over the top but you will (I hope) not be flying WOT for the whole flight, at say 1/2 throttle where it is lightly most of your flight will be done you only will have about 1000 watts, good for a lively flight on a 7 pound aeroplane.
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Old 11-09-2011, 06:47 AM
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kyleservicetech
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Originally Posted by woodfit View Post
Hi Guys

Finally got my watt meter coupled up to my Pitts with the new lipo's, it appears to have a stonking 2340 watts at full power with a 6s and 2s in series both 5000MaH and both at 40c, question is will she fly ?? Oh and the rpm without the prop was 7800 rpm good or bad?
Yup
As others in this thread have indicated, we need to know model wingspan, weight, motor brand and model number, propeller size. (That 2340 watts could be with a 28 inch propeller with 2 inch pitch! )

One good program to sort this stuff out is www.motocalc.com. However this program is only accurate if quality motors are used, where the manufacturers motor specifications are accurate. With some of the real cheap motor stuff on the market, that may not always be the case.

I've got a Hacker A60-16M motor, swinging a 19X12 APC-E wide blade prop at 6800 RPM on a 78 inch wingspan, 19 pound airplane. That power system runs near 3000 watts at full power, and pulls the model off the ground in about 30 feet.

Take a look:
Carl Goldburg Extra 330 Electric Conversion
http://www.wattflyer.com/forums/showthread.php?t=59273

Giant Scale electric motors vs Gasoline Engines
http://www.wattflyer.com/forums/showthread.php?t=58035

Thread on 70 size glow engine conversion to electric
http://www.wattflyer.com/forums/showthread.php?t=45222

Hacker 6S2P A123 powered Models
http://www.wattflyer.com/forums/showthread.php?t=44686
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