Hey guys I got the size 60 GP Stuka. I'm running it with the factory 600MaH battery pack from JR. The airplane hasnt flown yet. It has 7 servos. 2 are flaps, someone at my field told me I needed a better battery. Is this true? If so, what battery do I need? Thanks
~Vik~

What they meant was, you should be thinking about higher capacity than 600 maH with 7 servos. You'd still use a 4.8 volt pack.

There are a lot of options available for Rx packs. I recently bought some NiMH (Nickel Metal Hydride) packs on eBay. It cost me something like $24 shipped for 3 packs (and they had the right connectors), each has a capacity of 1500 maH's.

Using the 600 pack would mean checking the remaining capacity after every flight.
Dennis-

Nothin' wrong with a 5-cell pack though.

You're right. There's nothing wrong with 5 cells except, you need a regulator to keep voltage around 5V, and a 5 cell pack drains faster than a 4 cell due to higher current.
Dennis-

If two of the servos are being used for Flaps, I wouldn't worry about the battery load.

7 servos, 2 for flaps. That means 2 for ailerons as well?

Personally, I think you'd be fine on a standard 600mAh pack, but you might only get 3 "normal" flights before needing a recharge.

Just make darn sure none of the servos, espeically the flaps, stall at the end of travel. Nothing discharges a battery faster than a servo stuck just short of where it wants to be for a while. That kind of thing is easy to do on throttles and flaps, where there is frequently a physical limit to the control movement that you want to match with the servo. On thottle, it's not that bad unless you roar around at full throttle all the time, but since most flying will be "flaps up", you have potential there for a problem. Note that this isn't specific to the size of your receiver pack, just a tangent worth going down .

So you guys recommend me a battery with maybe 1100 MaH?? And on eof the flap servos vibrates when they're retracted, that drains the battery.

Well, not vibrate so much as if they "buzz", which means the servo is stalled and draining your battery pack like crazy.

As Montague said, you can stick with the 600 maH pack, but you should check it often!
Dennis-

What can I do so the servo stops buzzing???

If you have a computer radio you reduce the ATV or EPA percentage which reduces the servo "throws".

If using non computer radio you have to make mechanical adjustments to the linkage which is harder to explain. First thing to try is moving the control rod in on the servo horn (or closer to the output shaft). You can also move the control rod further out on the control horn at the flaps (or other control surface). The overall affect is the same as reducing the EPA.

Good Luck,
Dennis-

Yeah, it's a JR 421, its computerized. So I just take a little travel off the retracted position. I'll try that, thanks.

Even with a 1100+mah pack, I'd fix those flap servos. It's amazing the current a stalled servo can draw.

Would it be that they are buzzing because the retracted position of the flaps is making the servo push too much???