I am currently building an Ultra Sport +. I want mechanical retracts and the aircraft requires 5 servos. Do I need to upgrade my battery pack to a higher capacity or will 600mA/Hr work

I'd get a five cell (6V) 1000mah or 1100mah pack. It depends on how low you want to keep the weight. The increase in voltage from 4.8V will give you better response from the servos and the added mah will give you peace of mind because your landing gear depends on a good pack!

I have a couple planes with retracts on a 600mah and its fine. I also have one on an 1100mah five cell. That battery seems to last forever. If it's going to bother you, then upgrade it, you can use the 600 for something else.

I have a US 60 with Springair retracts (air) and 6 servo's. I use a 5 cell 600 mah pack. Works fine for the few times I flew it. Way too much for my abilities at the time. Flew fantastic. I would use a 5 cell 800mah pack myself if I did it over.

Mark Shuman

The increase in voltage with a 5 cell pack wont hurt any of my equipment? And it just provides increased responce. Futaba receiver with standard ball bearing servos is what I have. Thanks

Depending on what engine your going to use you may want to make your gear longer, When I built my US 40+ Here is what is left of my wing Poor plane had a tragic death, But it will give you a good idea on where to cut the bays for longer gear.

Dauntae