Mark,
Many flyers are using JR servbos with Futaba receivers with great results.

Here's the servos that I'm using in my BobCat XL:

Elevators (2) JR DS9411 They do fit....
Rudders (2) JR DS9411 82 in oz.
Nosewheel JR 4131 93 in oz.
Ailerons (2) JR DS8411 155 in oz.
Retract valve JR 351 enough torque for the job
Brakes JR 351 ditto
Gyro JR 450 no longer available, use JR 460

The JR 9411's require that you notch a corner from the PolyPly servo cover so the servo case can hang out a little. You can't see the case corner in flight, and there isn't any technical reason why that isn't okay. You can see it, but it is on the bottom.
The additional torque and metal gear train of the DS9411 makes a big difference. (82 in oz vs. 60 in oz.)

An 8411 on the elevator(s) is much larger than a DS9411. It has bags of torque, but it would be much more difficult to install, and offers no redundancy.


The two elevators, either of which is redundant in the event of a failure, could make the difference between having an airplane or having a smoking hole. I hope none of us make use of the redundant surface and servo, provides but since it's there, why not look upon it as insurance?

I realize that this didn't answer the entire question exactly, but is intended to be food for thought......This is my choice, and it works for me. 157 flights so far on my BobCat XL. I swapped out the JR DS3421's (rudders and elevators) for the JR DS9411's after 43 flights. One of them failed on the ground; drove hard over, melted the case, and fried the extension harnesses. Glad it happened during taxi back to the pits after a flight!!!


Good luck with your servo choice.

Harley Condra
BVM REP