Am getting ready to install 17cc gas engine in a 65 in. Mustang. I want to keep the weight down. If I use a 2200 Mah. nicad 4.8 battery

for the electric ignition is it feasable to use the same battery for my servos. The plane has 7 futaba 3004 servos & should come in weighing around 8 1/2 lbs.

You need to run a seperate battery for your ignition system and radio. I know you are looking to keep the weight down, but this isn't an area you can skrimp on. First, you don't the ignition system draining your radio battery to the point that you could lose power to the receiver. Second, and probaby more important the radio should be completely seperate from the ignition system in order to keep RF noise from the ignition system interfering with the radio. By running off of the same battery you could easily transfer RF noise straight into the radio, which can bring down your plane.

Ken

Something one of the JR race plane pilots showed me two weeks ago for saving weight on the battery pack may be of help. He makes up his own 6 volt packs using AAA size batteries. You can have them made up for you if you don't want to do the soldering and shrink wrapping yourself by going to any batteries plus storeand having the packs made fofr you.

Thanks, Radio Shack has battery holders for AAA & AA batteries. The ignition pack would work since I only need around 900 MaH. For

the servos I usually use a 2200 MaH battery pack. The guru at the field is using a 1-2-3 battery system on his 1/3rd 3D planes. I will

have to see what he does

2200 MaH Ni-Cads? What is it a 4 cell sub-C pack?You could save a ton of weight either using NiMh or, preferably, a A123 pack. Syssa makes a BEC (battery eliminator circuit) that does just what you describe but in a safe manner. It uses the receiver batttery for the ignition but isolates and protects the receiver from ignition interference.

Exactly...

Bob

I got A123's from WrongWayRC that uses a single 2200 pack to power both reciever and ignition, give him a call, tell him what you want and he can configure the leads and step down for you.

I use the 2/3A NiMh batteries for Ignition also,, you can get 1600 mah ones and the are very small and weigh about 3.5 oz
A 2s 2300mah A123 weighs about 6oz. then add the weight of the BEC probably 1oz
A 5 cell AA pack weighs 5.4 oz


You wont save weight with the A123 unless you use the BEC with it, you may save 3 oz vs. 2 packs, But you'll need a A123 compatible charger too if you don't already have one,, That's a lot of money to invest to save 3 oz