I just bought two BLS174 sv servos for my winter build. I have not used these before and was unfamiliar with them. Nice shape for an aileron servo with good output weight and speed BUT, the out put spline is a 25T 4F not the common 25T 3F on most mid sized Futaba servos. This is the larger output spline that was once on the S9152 and S9153 large servos now discontinued. I have been unable to find any after market out put arms so you are limited to the nylon wheel and 6star out put arms provided with the servo. If I am incorrect with any of this, please correct me and if you know of a source for aftermarket out put arms for the larger spline on the BLS 174sv, please post it

Odd that they are still using that larger spline. To be fair, a lot of us use the large pound servo arm for ailerons anyway. I would not be worried about using it.

I use the round wheel and then attach the carbon fiber servo arm....works great.
https://www.f3aunlimited.com/gator-r...iber-servo-arm