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Old Jun 25, 2003, 03:33 PM
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mars's Avatar
San Francisco, CA
Joined Jan 2002
577 Posts
Funcraft P-51 KP-00 Prop Help!

Hi All,

I have a converted Funcraft P-51 with a KP-00 in the pointy end with a U80 prop. The AUW is 1.1-1.2oz.

I launch the thing and it wallows for a while and then sinks to the ground. It looks to me that I am not getting enough thrust to climb. As the plane wallows I have elevator and aileron response, it just will not climb or even stay in level flight for long.

My first reaction is to put a bigger prop on the motor I have. Do you think this will help? I can only pull 1A as I am using the RFFS-100 and a 145Mah Lipo. Will a GWS 4.5x4 be too much for this motor? My gearing is the stock KP-00 set-up.

If a new prop is unfeasible, do you think a LV m-20 with a different ratio might do the trick? I also have a DC5-2.4 geared 5:1 sitting around but I do not think it will work well on a single Lipo.

Please help!!!

Thanks you in advance,

Mars
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Old Jun 25, 2003, 04:48 PM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
8,406 Posts
Yes, you are on the right track.

A higher gear ratio and a larger prop are needed.

DWE or somebody sells a Didel gearbox that should work better. They also make a higher ratio KP-00 motor. Perhaps Sky Hooks sells it.

The little P-51 needs more speed to keep aloft.

Good luck!
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Old Jun 25, 2003, 05:01 PM
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Mike Taylor's Avatar
Camarillo, California
Joined Apr 2002
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The KP-00 and U-80 should be enough to fly one of these. A heavy Spicy Wing is about the same weight and wing area, and they fly great at reduced throttle...

It sounds like you may not be getting up to flying speed. Try a harder launch (they do need to go pretty quick to really fly). If you can't get it up on the step with the U-80. you might try to locate a KP 2-bladed adjustable prop - these generate more poop, and you can adjust the pitch to give a little more speed to the plane... I've got some and they are better performers. I got mine from Tony at T & A Hobby Lobby (3512 W. Victory Blvd., Burbank, CA 91505 - (818)842-5062).

Are you running it with the supplied foam spinner? That cuts into the blades a fair amount. The KP adjustable prop would give a little more blade area outside the spinner. If you are running the spinner, make sure that everything is centered and in balance - any out of balance here will add more friction to the bearings and may cut into the performance...
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Old Jun 25, 2003, 05:07 PM
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mars's Avatar
San Francisco, CA
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thanks greg & mike

I am running the spinner and it is out of wack by a little bit. I will remove it and see if that helps.

I am giving the little plane what seems to me like a good push, but I will push a little harder on the next try.

I'll let you know how it goes w/o the spinner.

Mars
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Old Jun 25, 2003, 05:38 PM
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Buffalo, New York
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Mars,
If that doesn't work you may want to try the 4:1 gearbox that Bob Selman has. It seems to produce more thrust at the same current.

Regards,
Dan Hurd
DWE
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Old Jun 25, 2003, 07:15 PM
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Dan Leonard's Avatar
Lenexa KS USA
Joined Jun 2001
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Dan
I agree with using the Kenway M-20 gear box from Bob Selman. It's funny that this came up today as I just finished putting one in my P-51 last night and it fits great with room to spare. With a little creative mounting I didn't even have to cut it open. The 10 cm prop sticks out plenty far. I haven't tried to fly it yet but I have one on another plane and it feels like it has about double the thrust of the KP-00. Best part is nice and smooth and quiet. I'll post a picture later.

Dan
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Old Jun 25, 2003, 08:53 PM
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Thanks guys

Dan, I'd love to see a picture when you get a chance.

Mars
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Old Jun 26, 2003, 12:00 AM
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Brentwood,TN
Joined Mar 2001
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I am using the kenway gear set (homemade) with a gws 4.5x4.0 on M-20 motor, and it flies with authority. Really no power problems. It even loops. Dan, if you get a chance post those vids of inflight. I think the m-20 and kenway gears work very well.
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Old Jun 26, 2003, 07:57 AM
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Buffalo, New York
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jhas,
Actually they are already there I just haven't created a link to them yet. but here is a direct link

Video One
Video Two
Video three
Video Four

Regards,
Dan
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Old Jun 26, 2003, 10:26 AM
Team 30 Micro EDF
Mike Taylor's Avatar
Camarillo, California
Joined Apr 2002
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Dan, the last link is bad...
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Old Jun 26, 2003, 10:51 AM
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Sorry,
It should work now.

Dan
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Old Jun 26, 2003, 01:34 PM
Team 30 Micro EDF
Mike Taylor's Avatar
Camarillo, California
Joined Apr 2002
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Yep, that's all better now...
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Old Jun 27, 2003, 10:47 AM
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bselman's Avatar
sw missouri
Joined Sep 2001
399 Posts
Another Prop Suggestion

Another thing to consider --- The GWS 0303 prop does an excellent job on the KP-00 with the 2.67:1 gearing. I'm using them now instead of the U-80 and get a noticable increase in performance.

The shaft needs some shimming to get a good friction fit. I use wire insulation or heat shrink tubing.

Bob
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Old Jun 27, 2003, 11:10 AM
Team 30 Micro EDF
Mike Taylor's Avatar
Camarillo, California
Joined Apr 2002
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Bob,

Have you checked the current draw with that combo by any chance? Does it warm the motor up very much? If it is not too much load for the motor/gears, I may have to snag one for a CF copy...
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Old Jun 27, 2003, 11:30 AM
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sw missouri
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Current draw?

Mike,

I haven't measured it. I'm sure it is much higher though because the increased performance doesn't come for free. My best guess is that it is a little over 1 amp at full throttle on the RFFS-100 and the 145 lipoly cell. I don't use full throttle very much because the speed builds quickly on my SLW (Gary Jones design). But the extra power is very nice for loops and when you get in trouble. The RFFS-100 handles the power with no problems and the KP-00 doesn't get hot.

Bob
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