About to put the finishing touches on my Seagull Models Pilatus PC-9 1.20. The reviews used either a 5 cell 2500-2700 maH NiMH battery. My buddy gave me a pretty much new 4 cell 2700 maH NiMH battery and was wondering if that would be alright. Using an evolution 1.20 two stroke with 7 spektrum servos. 2 of the servos being used are for the retract system.

Personally I'd run it on 6v, especially if Specktrum rx. Servos are a bit faster and stronger, and less risk of a brown out.

For the last couple of planes I've set up I went with unregulated Li-Fe, and I really like them.

There's not much, if any, difference in amperage available to the flight pack when comparing 4 cell NiMh vs. 5 cell NiMh.

I would guess you'd be fine unless extending the retracts while on knife edge using all digital servos?

I'd run the 5 cell pack.

How much is your plane worth vice the cost of a battery?

Ihave been using the 5 cell RC car packs, they give up a lot of amperage without voltage drop. http://www3.towerhobbies.com/cgi-bin...LXMUG9&P=K

Attached is a diagram showing how to isolate a battery for the rectacts that is seperate from the receiver power.  That is how I would run electric retracts. 



http://www.rcuniverse.com/forum/m_86.../anchor/tm.htm

That looks like a very wise way to set it up. I presume the point is so that if a retract binds up and pulls a bunch of amps, it won't draw the receiver voltage down...

Yup, thats exactly the point