8611A or 5955 ideal servo arm setup

[airborneSGT]

Hey all,

I want some honest opinions/input/advice on people using single 8611A's or 5955's for 40% elevators. To be specific I am wanting to know what length of arm are people running?

So far I have seen 1.25" to be a safe bet for said setup. However, I also happen to have 1.5" arms and was wondering is it alright to use them on a similar setup or am I taking away too much of the mechanical advantage.

Of course the next obvious step is to double up servos per control surface but I am trying to avoid this. I would apreciate any input.

The 40% I have has been using single 5945's per elevator half and 1.25" arms. I am swapping out
them with some 8611A's but not sure if using the 1.5" arms is going to be alright.

Not making a servo brand war. My other thoughts are about that nifty Durant direct drive which would eliminate most of the problems of current setups.

[DKnippen]

On my 40% one 8611A per Elevator is more than enough for Imac. I use I.25 " servo arms and from the hinge line to push rod is also 1.25".
I don't know about the 1.50" arms but guys are using them for 3-D flying. If you go with 1.50" make sure from the hinge line to the push rod is the same.

[Shawn Berkheimer]

The 8611 with 1.5" arms will have enough power to operate the elevator. I used this setup on my CA 38% Extra for over a year. I was using 1.5" servo arm with a 1.5" control horn measured from the hinge line just as Dan suggested. I did however experience lots of gear wear. I rebuilt the servos and went to using 1.25" arms with the same 1.5" control horn and the gears are wearing better.



Shawn

[KrisW]

	Quote: Originally Posted by airborneSGT
	Hey all, I want some honest opinions/input/advice on people using single 8611A's or 5955's for 40% elevators. To be specific I am wanting to know what length of arm are people running? So far I have seen 1.25" to be a safe bet for said setup. However, I also happen to have 1.5" arms and was wondering is it alright to use them on a similar setup or am I taking away too much of the mechanical advantage. Of course the next obvious step is to double up servos per control surface but I am trying to avoid this. I would apreciate any input. The 40% I have has been using single 5945's per elevator half and 1.25" arms. I am swapping out them with some 8611A's but not sure if using the 1.5" arms is going to be alright. Not making a servo brand war. My other thoughts are about that nifty Durant direct drive which would eliminate most of the problems of current setups.

Okay. . NOT a brand war .. statement of FACT.

I tried 8611's in my SuperExtra using 1.25" arms. . one per elevator. They worked fine. . .for 22 flights. Then I replaced them with 5955 Hitecs because the gear slop was out of hand and just not acceptable. . over 1/16" back and forth at the tip of the output arm. The SAME 5955 HiTecs, after a further 22 flights, a crash, put in another airplane for 52 flights. . now reside in my MX-2, and work flawlessly for 35 flights so far. They have always been on Elevator, since I matched the throws of this pair of servos with a programmer. so, that's a total of 109 flights, all on elevator, with 1.25" arms .. and the gears are as tight today as they were on flight #1 over a year ago.

The 5955's cost less, are programmable, and get tremendous geartrain life. . .AND they are just as fast with a higher torque rating. 8611a's use the same basic geartrain as the 8611's, with a beefed up motor and some casing modifications.

So, let's look at it logically. . which one makes more sense?

[airborneSGT]

Ha ha...like I said its not a brand war. I own both servos but why even spend more money for some 5955's if I have 8611A's just chillin!

Good point and it seems that 1.25" is the way to go depending on exact elevator setup. A good setup I think is what to look for regardless of brands.

[RollingHarrier]

On both of my 40%s, an edge and an extra, I use 300+ (no brand mentioned on purpose) and 1.5 inch arms on my elevators. Just make sure you have 1.5 inch from the hinge line to the hole in the horn where the ball-link bolts thru to maintain 1:1 mechanical advantage. This gives me sick throw for 3D, great resolution and more than enough power. I also save a ton of weight by cutting down on the number of servos. On my ailerons I use two (300+oz) servos leaving the middle one empty and 1.25 inch arms which give me more than enough throw.
Oh ya I use MLP arms from AirWild. good stuff.

[airborneSGT]

Coolness. I mself am working with a 40% Carden Cap that has 2 servos per aileron and one per elevator half. I think I will roll with what I got and then go from there.
My problem is I am mainly into 3D so I always have to check the weak points often or try to avoid them all together.

[TonyThomasian]

i have 2 8611's total on my elevators on my comp-arf 3m extra 330 and it has power for 3ding. it has alot of play in the servo though. Last time i was going to take off i was checking my control surfaces while taxing on the runnway. When i kept giving up and down elevator to make sure everything was working alright, i noticed that once in a while one of the elevator servos would stay down and the other up. I got lucky because if i took off and gave it elevator, it could of easily snap the plane and go right into people in the pits. I got really lucky! So i sent the servo to horizon and their still taking a look at the servo. but yes the 8611 has alot of play in it.

[DKnippen]

	Quote: Originally Posted by TonyThomasian
	i have 2 8611's total on my elevators on my comp-arf 3m extra 330 and it has power for 3ding. it has alot of play in the servo though. Last time i was going to take off i was checking my control surfaces while taxing on the runnway. When i kept giving up and down elevator to make sure everything was working alright, i noticed that once in a while one of the elevator servos would stay down and the other up. I got lucky because if i took off and gave it elevator, it could of easily snap the plane and go right into people in the pits. I got really lucky! So i sent the servo to horizon and their still taking a look at the servo. but yes the 8611 has alot of play in it.

Tony ,
Don't know whats going on there but I don't think it's the servo !
Dan

[notorious_benny]

I agree, sounds more like a glitch of some sorts!