Hello, I am about to purchase my first gas engine in a few days...a DA50 for my Chip Hyde Cap. I was just wondering if a seperate battery is needed for the ignition unit, and if so what kind. I do not own any li-po batts and am using a 2700mha NiMH for the aircraft reciever. Any other help about gas engines will be greatly valued.
Thanks, Erik.

Yes, you need a separate battery to power the ignition. Approx 1000 mAh. Most ignitions are designed for 4.8 volts, but the newer DA may accept 5-cell (6.0 volts) or even unregulated 2-cell LiPo (7.4 V). The instructions will tell you.

Keep your engine elctricals well away from your radio electricals.

I use a regular radio switch - charger plug assembly for my engine.

Enjoy,

Jim

Just out of curiosity, how come it would be a bad idea to mount my eninge battery where my receiver battery is now..seems like it would be alot easier to keep a good c.g.

REVgst, I'm not sure I understand your question. You definitley need to batteries in order to isolate them from each other. The ignition battery may carry some noise in it from the ignition unit. By having two batteries, you eliminate the noise of the ignition from entering the receiver throu the battery connection. You can put the two batteries in about the same place in the fuselage to get the CG right. I still try to keep them a few inches apart anyway.

another important thing is you must use plastic pushrod in trotlle, and if you can use pcm system
good luck

DMcQuinn,

Is it okay to use the ignition battery as a ballast weight in the rear of a model, and connect to the ignition switch mounted just aft of of the engine using a shielded wire running inside the fuselage.