ORIGINAL: Harley Condra
Jason,
The reason that many of us do not like to use digital servos on flaps is a simple one: Digital servos use more battery than analog servos.
A pair of extended flaps, experience heavy airloads. The airstream pushing against the flaps, cause the digital servos power consumption to rise dramatically, as they constantly push against the airloads to hold their position.
Here's a simple test:
Turn the radio on, lower the flaps to landing position then slightly apply pressure to the bottom of both flaps to simulate the airstream. The digital servos will really start to "buzz" as they respond to the applied pressure.
If you hooked up a VOM to the battery and measured the applied load, I'm very sure you would see an alarming voltage spike.
As larger, more powerful servos arrive in the marketplace, and more of them are installed in larger more powerful airplanes, the battery power available must rise accordingly.
Should you decide to use digital servos on flaps, please make sure you adjust your battery capacity and voltage upward. Higher voltages and regulators, and high capacity cell are in order.
As for the Super Bandit speedbrake, it makes good sense to install it. The added drag of the extended speedbrake makes it possible to keep the engine RPM higher on final approach. Since you are at a higher RPM, the spool up time will be reduced in case of the need to go around. Just a few words of experience from my eight years flying Bandits.
Send me your 2721's....I'll use them.
Cheers,
Harley Condra
BVM REP
JetCat REP
Harley,
I can not claim 8 years experience in flying Bandits I'm only at 7 yrs although I have owned 5 and have sold 2 on so I still have 3 currently (one classic one super and a Arf in build) As I stated in my post " if the set-up is done perfectly" and you set the flaps up so the servo arm and linkage are straight when the flaps are in the landing position then there’s no chance of any drastic current drain. I always thought the reason BVM did not use digitals on the flaps was because of the drain that could occur in the up position if the throws were not adjusted perfectly?..But I'm sure they now recommend digitals on the arf bandit flaps? As far as the battery set up goes I use a single 4 cell 2400 SCR pack with two leads, going through two switches and two battery feeds in to the RX, one in the battery socket and the other in a spare channel in a matchbox or Y lead. I too have about the same number of flights as yourself and have never had any battery issues either. I think there’s a few good ways of doing a job right when it comes to servo or battery choice and no one person, although they may think they have, has the only successful set-up. Some use regulators, some use two battery packs, some use one and some even use three! and some favour opto isolators. Personally I like to keep things simple and it has always worked for me.
Jason