battery size for gas engine
 

hi
i am building a arrow 55 biplane 60 size and going to use a satio fg 14 gas i bought a fight kit from tower 4 3004 servos rec battery it came with a 4.8 600 mah sanyo battery is this battery enough to run the engine i am going to use a 6 volt 2000 mah for the servo and smoke system ,thanks

Saito recommends a minimum of 1000 mAh battery.

Also it should be a 6v pack. For the small amount of fuel these small gassers use it can be in the air for 30min + on a tank. Put the largest capacity pack in that will fit.

I would not install a smoke pump on the same battery as my receiver. That's just inviting trouble. To stay in step with Saito's suggested minimum ign. battery, maybe replace that 600 with a battery big enough to run the smoke pump as well as the ignition? Worst case then, assuming the Saito ignition is set up similar to the Rcexl, is that the pump will put the Saito ignition into limp mode if the voltage gets too low.

If I were setting up that airplane I would increase to a 2700 mah LiFe battery and run the ignition with a Tech Aero IBEC. The ignition draws approx 1000 mah at full throttle. The standard analog servos you are using draw very little current, the only real variable is your smoke pump but I would imagine 1000 mah or less. The 2700 would safely give you an hour of flight time. If you want more safety margin you could go with a bigger battery or top off every three flights.

I run 6 servos and ignition off the single airborne battery. The ignition uses the Tech Aero ibec.
The battery has been 1800-2200 mah capacity 2s lipo and gives about 75 minutes of flying. The end voltage of the 2s lipo is 7.45 to 7.5 V for the 1800 and about +.1 V for the 2200.

The 2700 Shawn suggests should give one hour of flying if the smoke pump uses about 500 mah. Let's keep in mind the smoke pump will be run a fraction of that hour. What's not known is whether the pump generates RFI back to the RX.

I check the airborne bat voltage after the 4th and 5th flights. I track flight time as well