View Full Version : Gws P-51

07-31-2005, 08:34 PM
Took my new Stang out this morning thinking it was going to eat up the sky........NOT............I was running the setup I had in my GWS Corsair(with a little faster prop) E-Flite Park 370 5.33 gears and a 2 cell lipo. It took to the air pretty good but had no power to do anything after it got up there. I have a couple of 3 cells bats I use on the Corsair(new setup), but I can't use a 3 on the motor I have in the P-51. I see that Alfa runs the blue MP jet outrunner on their P-51, and my plane weighs about 1 oz. more than the Alfa. I use the MP red outrunner im my Corsair and it flys great. My question is will the Mp blue fly my model or is the one ounce going to make that big of a difference. I was also looking at the AXI 2212/34, but don't really want to spend 80 to 100 bucks on motor and radial mount set......Any suggestions would be great.........GW

Matt Kirsch
08-01-2005, 01:49 PM
I highly suspect that your existing motor is capable of more than you give it credit for. Which 370 motor is it? I suspect that it's the 370-5400, which can take a 3S LiPoly if you gear up, prop down, and above all, watch your throttle.

08-02-2005, 12:18 AM
Hi Matt,
I am sure it is capable of more power. You are right it is the 5400kv version. Ok so it will take a 3 cell. How hard can I push it with a 3? I have a bad habit of pushing the throttle up, you know "It can take just one more click" and then boom!!!!LOL Thank you for letting me know about the 3 cell capablity. That will open a few doors, and let me know about the limits. Thanks again.............GW

08-04-2005, 12:19 AM
Well I geared up and proped down on a 3 cell, it seems to have more thrust and power on the bench. I won't have a chance to take it out untill this weekend. Maybe I can get some video..............

Reformed Nitroaddict
08-04-2005, 01:44 PM
gullwing- yes, you should have no problem on that plane. That motor is the equivelant of the Himax 2015, and is capable of about 12V and 12amps. So a 3S pack is just fine.

On a 5:1 gearing you mention, I have seen that motor run on a 10x7 prop and draw about 12.5amps max, and a 9x6 prop drawing about 9.9amps. Both should work on your plane, but would probably be better to go with the 9x6. Motor can handle it just fine and should produce limited vertical performance.

08-04-2005, 11:41 PM
Thanks Nitro,
I went 6.6 on gears and 8x6 on prop. I am pulling 9.7 amps and 10.2 volts. I figured this is a place to start. I know it will keep it in the air. I will fine tune it this weekend if weather permits.... Knowing that the 5400kv will take a 3 cell made it alot easier................GW

Reformed Nitroaddict
08-04-2005, 11:45 PM
No problem gullwing - although, if going with the 6:1 gearing, I would up the prop diameter to at least 9inches, but a 10x7 would probably work best.

Want thrust? 10x7 on 6:1
Want speed? 9x6 on 5:1

08-05-2005, 12:47 AM
Tried a 9x6 and then a 9x4 pulling too many amps for the batt. I really don't know where they get their specs. On my corsair I run an MP Jet outrunner. According to their specs it should be running 9.4 on a 3cell 1500 and a 10x6 prop.....NOT...........a 10x6 on my Wattmeter shows 15.7amps!!!! I don't understand. I thought I was doing something wrong so I took it up to the LHS and had them do a test and they came up with the same readings.....15 would be fine but I'm running a Kokam 1500 with a 8C discharge..... I get higher than spec. readings on the park 370 as well. Any ideas? Both motors where new when I checked the amps. Props were balanced and running smooth and quiet.. Every motor I have seems to run alot higher amps than the specs say they should.....If you could shed some light on this I would be greatfull ...........GW

Reformed Nitroaddict
08-05-2005, 02:21 AM
Hmm - I don't know. I know on my formosa, I was running a 9x6 APC SF prop on 5.33:1 gearing, motor was a himax 2015-4100kv motor. Pulled 9.9Amps at WOT.

08-05-2005, 02:56 AM
Yeah that is what I said Hmm, but oh well, I figure all that is important is that even with the setup I have now(in the Corsair) it flys with authority, and the flight times are in the range of 10 to 12 minutes.

Matt Kirsch
08-05-2005, 03:21 PM
Prop brand has quite a bit to do with the performance. GWS props don't pull nearly as many Amps as the APC Slo-Fly props of the same size.

Beyond that, I have absolutely no idea what you could be "doing wrong" to cause the motors to draw more Amps than expected. If the problem were limited to just the one geared motor, I'd say check the gear mesh. However, you see the same thing on an outrunner.

It's not the battery. If anything, I'd expect you to read low with the battery you're using.

It's not the meter. You've had your setups tested with another meter...

Truly baffling.

Do you live at sea level? Where I live, I generally get the "right" numbers for my setups. The major airport in the area is at 660' above sea level, IIRC. Don't know if a few hundred feet of altitude would make that much difference...

08-06-2005, 12:00 AM
Darn near sea level I live south of Houston TX. I don't think that would make a difference either. I am not without education in electronics. I have been an auto tech for 15 years now, and have seen it all when it comes to automotive computer systems and electronics. This is one I just can't seem to figure out. Well thanks for the replys, and if you happen to think of something let me know.......GW

08-06-2005, 09:34 PM
That didn't work eg. crash forum................LOL

08-12-2005, 10:16 AM
Actually elevation does make a difference. At higer altitudes you'd need to gear it for more rpm to compensate for thinner air.
I would try the stock gearing (5.33:1) with a 9x6.

08-14-2005, 06:19 PM
I got rid of the whole gearbox problem and just fabricated a motor mount for an MP Jet outrunner and a APC 8x6E prop..... Flew it today and is it fast. It will go virtical alot longer than I am willing to let it. Flight time is in the 12-15 min. range. Brought it in at 13 today and still had power to spare. I have the same setup on my Corsair but the Stang just out flys it...........GW

08-14-2005, 11:35 PM
Good job on making a firewall mount. I did one a while back on a Spit, much more solid and simple. Have fun with P-51, now no more reasons to crash lol.

08-15-2005, 12:09 AM
Yeah what you can't see is that I epoxied two dowel rods into the bottom of the fuse. and epoxied those to the mount, I figured that would hold it I did the same thing to my GWS Corsair and it is still holding up after many, many flights and a couple of rough landings..... Oh I will find some other way to crash. I don't really need a reason. LOL.............Happy flying................GW