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Which Prop - See chart in thread - Help.

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Old 06-30-2005, 12:54 PM
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Default Which Prop - See chart in thread - Help.

Cannot decide which prop would be the best fit for my plane.

Plane is 17.8oz fully loaded with motor and batts. Here are the calc stats, which would provide the best performance for basic aerobatics and easy flight.

10x4.7 = 7Amps, 59w/lb, 17oz thrust, 28mph pitch speed

10x7 = 8Amps, 75w/lb, 18oz thrust, 39mph pitch speed

11x4.7 = 8amps, 75w/lb, 22oz thrust, 26mph pitch speed
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Old 06-30-2005, 01:00 PM
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Default RE: Which Prop - See chart in thread - Help.

This is the e-starter, right?

I know you already heard from me... but I would go with either of the last two - Skip the first one. Try one, if your'e not happy with it, it's easy to change to another.
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Old 06-30-2005, 07:59 PM
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Default RE: Which Prop - See chart in thread - Help.

Thanks - Decided on the 10x7 - WOW!!~!!

Well thanks for the help on prop selection everyone!!!

Went flying today, no wind to speak of finally. Running the 2015-4100 on D Gearing with the 10x7 prop.

Results:

11.1V GWS 1300mah 3sLipo -
WOW!!!! Talk about turning the E-Starter into a different plane! Applied full throttle, gave a lil toss, and she climbed at about a 45-60 degree angle with no intent of slowing down. Good, quick, level flight was acheived at about 70% power and the plane just cut through the air. Had a spectator, so I came down low over the runway at about 20-30 feet, inverted, then applied full down elevator, plane shot straight up with full airleron deflection and two nice rolls. Leveled off after that. Plane will go vertical for about 75-100 feet before running out of juice. Total flight time was 11:45 seconds with no power loss. Imagine that I could probably get about 15mins out of her before LVC.

9.6V Sanyo 730mah 8cell AAA Nimh -
Had to give her a good toss to get enough airspeed to climb, but once she got up to speed, was a marked improvement with this prop and gearing over the C gearing and 10x4.7 prop I was using before. Significant power, great climbing ability. Could sustain about a 30% climb rate at full power. Was able to throttle back to about 90% power for cruising. Total run time was 6:05 with significant power loss towards the end, but still plenty to land nicely. Imagine that a 7-8min flight time could be done if aerobatics were not enjoyed.

8.4V GWS 730mah 7cell AAA Nimh -
This pack was able to fly the plane, but it was tough. couldn't really get enough airspeed to creat the lift needed. She flew, but climb rate was only about 15 degrees and full power was needed most of the time. I think an 11x4.7 prop would really help this pack. Total flight time was 6:50 and still had plenty of power when I landed. Imagine 7-8min flights could be had with a different prop.

Overall - the lipo was just fantastic, came down barely even warm. At 8C she can handle about 10amps, and thats plenty for this plane. At 32.00 - the price is so low, that I can handle the slightly smaller amperage levels. I am definatly going to pick 2 more packs up , so I can run only these and not have to wait for the hour long charging time.
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Old 07-01-2005, 09:05 AM
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mike tully
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Default RE: Which Prop - See chart in thread - Help.

Nitro,

A couple of points to consider.

An electric motor spins at fixed number of rpm/volt. In the case of the 2105-4100, that number is 4100 rpm/volt. The seven cell pack will spin the motor at 34,440 rpm. The eight cell pack 39,360 rpm and the 3 cell lipoly at 45,510. Given the same prop and gearing, the 3 cell lipoly will win this race every time. You could change the gear ratio and/or prop dia/pitch to get exactly the same flight performance with a 7 or 8 cell nimh pack, but the nimh pack would have to put out the same number of watts as the lipoly pack.

These AAA nimh cells may be good for consumer electronics, but they are absolute crap for e-flight. Way too much internal resistance. Why GWS continues to push them is beyond me. They are really only good for about 5-6 amp continuous use. For the 7 cell pack that is 42-50 watts. The 8 cell pack is good for 48-57 watts. The 8c 3 cell lipoly pack can support a 115 watt load, or about twice what those junk AAA cell can do. The 2015 motor can only handle about 105 watt, so this this motor/battery combo is a good fit. Throw out the AAA cells.
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Old 07-01-2005, 09:26 AM
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Default RE: Which Prop - See chart in thread - Help.

Mike Tully - I have heard this before and agree 100%. At the moment, I am on limited funds, so I have to slowly purchase lipo packs one at a time. The nimh packs give me something to do and fly while waiting for my single lipo pack to charge.
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Old 09-30-2019, 03:48 PM
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Mike
Quick change of subject. Where did you get the spinner for the Twomosa? I've got the kit and that spinner really is part of the look.
Thanks,
Mike Norris
San Antonio
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