Graupner P-51 electric?

[demonGti]

Hi guys, I bought myself a Graupner P-51 Mustang 70" about two years ago with the intension of putting in a Saito 150. The plane is still in its box but I have been toying with the idea of going electric. I have a fair bit of experience with smaller electric planes but nothing of this scale.

Can anyone in the know advise me of what the "best of both worlds" setup would be to fly this bird as scale but still have enough power for fair vertical climb? I can't afford the biggest and best and need to get the setup right first time.

The kit weights ± 9.9lbs and AUW is supposed to be ± 13.2lbs.
I think I need about 1500W of power but stand to be corrected.
Do I go for a fat outrunner or a geared setup?

With lipos beeing so costly I suppose geared would be better?

Any suggestions would be appreciated.

DemonGti

(Sorry, I only noticed now that a 70" scale warbird does not qualify for this forum :o , but any advice would still be appreciated)

[Jocke]

Motors i feel has good price but same time performance/quality is the Hyperion, maby the Z4045/14 and a 18" prop!? or if you are aming for big scale like prop 4blade maby a Z50xx, then a Jeti Advance 90 or Hyperion 90 controller, 10s Hyperion or Flightpower 3700 Lipo would be my choice.

Other flyers here have more experience on the Z50xx motors so they might have some recomendation to your plane with this motor!?!?

[Michael in Toronto]

1. Can anyone in the know advise me of what the "best of both worlds" setup would be to fly this bird as scale but still have enough power for fair vertical climb? I can't afford the biggest and best and need to get the setup right first time.

2. The kit weights ± 9.9lbs and AUW is supposed to be ± 13.2lbs.
I think I need about 1500W of power but stand to be corrected.
Do I go for a fat outrunner or a geared setup?

3. With lipos beeing so costly I suppose geared would be better?


1 and 2.
I would suggest an AXI 5320-34 outrunner and a 90 amp speed control on 6s lipos. If you want to go straight up, use an AXI 5330-24, 90 amp speed control (or higher) and 10s lipos.

3. The cost of lipos should have nothing to do with your choice of outrunner or geared motors. Although expensive, the lighter weight of lipos as compared to nicads is what is allowing us electric flyers to finish our glow-or-gas-intended planes as electric without a weight penalty.

If you contact Hobby Lobby, they will help you determine which power system to use.
http://www.hobby-lobby.com/index.htm

[demonGti]

3. The cost of lipos should have nothing to do with your choice of outrunner or geared motors. Although expensive, the lighter weight of lipos as compared to nicads is what is allowing us electric flyers to finish our glow-or-gas-intended planes as electric without a weight penalty.



Thanks for the advice, what I meant was:

A) Geared setup = less current draw = smaller, lighter, cheaper lipos
B) Outrunner = more current draw = bigger, heavier, more expensive lipos

I have a 70amp ESC with a 90amp peak rating, could I get away with using this? But it only handles 6-8S lipos.

[jamin]

Watts are watts, no matter the amps!

Why not give us your budget for a power system and then we can recommend the best bang for the bucks?

[Michael in Toronto]

I use AXI and E-Flite outrunners, and older geared Hacker and Kontronik motors. My experience shows that for higher quality motors, inrunner and gear-drive systems are more expensive, and use the same level speed controls and batteries.

I use a 77amp Jeti speed control in my 16 pound 1/4 scale Piper Cub on 10S8000mah lipos and with an AXI 5330-24. This is the upper limit for the speed control, but I have not mis-used it and am having no problems.

I suppose if you use 8s lipos and stay within the limits of your motor and speed control, you should have no problem.

Good luck.

Don't be shy. Ask Hobby-Lobby for a suggested power system for your plane.

[jamin]

22v under load at 70 amps is 1540watts. So a 6s could produce 1540 watts. An 8cell pack under load is 30v at 50amps is 1500watts........etc

[Michael in Toronto]

Yes, both setups produce the same total watts, but the system that draws lower amps will fly longer.

Many sport flyers that I know try to keep total amp draw at less than 40, or even lower than 30 amps, and use more volts (cells) instead. Generally, your system will run cooler at lower amps.

You can check costs for many motors, speed controls and batteries on Hobby-Lobby's website.
http://www.hobby-lobby.com/

[demonGti]

Thanks Jamin.......Thanks Michael in Toronto for your advice, I will peruse the Hobby-Lobby site and drop them an email, but shopping at H-L is a bit beyond my budget.... our currency is 7.5 to the $US so buying branded stuff from them is extremely expensive for me. I have bought a few items from United Hobbies in China and I have to say I have only had good results so far.

Once I get my P-51 in the air I'll post what setup I'm using.

Thanks again!