Rudder servo location question....

[alienteabagger]

Is there any real benefit to having the rudder servo mounted on the tail boom as opposed to in the servo tray? My heli came with the rudder servo mounted on the tail boom. I'm not too crazy about having that servo there becuase it get all covered in oil from the exhuast.

If I move the servo back to the servo tray, will I notice any difference in flight characterstics?

[BarracudaHockey]

I prefer mine in the canopy. I don't like the collective push pull either so it works out, my Titans have the standard V2 collective setup, and a front mounted servo.

You'd have to be a pretty gifted pilot to tell the difference.

[archiebald]

One BIG advantage of having the servo boom mounted is that you don't have to reset the linkage for optimum centering every time you adjust the belt tension, or when you do any maintenance that involves loosening the boom.

I fly two Raptors, one is boom mounted, the other is stock. Both are running same servo / gyro combination with identical settings and the boom mounted one is so much better, even I (a not particularly gifted pilot) can tell the difference.

All IMHO.

[BarracudaHockey]

"better" in what way? Cuz I have flown plenty of the boom mounted ones and can't tell a difference.

[alienteabagger]

I guess it doesn't matter much where the rudder servo is.... But wouldn't the oil from the exhaust eventually seep into the servo thus ruining it?!

[archiebald]

"better" in what way? Cuz I have flown plenty of the boom mounted ones and can't tell a difference.
Better as in more positive. With the canopy mounted servo it feels sort of mushy, as if I were using a slower servo, or had less gain set on the gyro. On the boom, there is a more positive snap.

BTW, head speeds are the same and running on governors, servo horn centers are the same also.

Maybe I should have mentioned one point - I am using a Quick UK carbon pushrod on the boom mounted servo.

You've only got to look at the flex in the linkage rod on the canopy setup to understand that it can never be as sharp and positive as a boom mount. It has an offset at the joint, and if you install it correctly, you have to bend it about 10~15 degrees before it gets to the servo. These kinks are major flex points when you are asking the servo to work hard. And if that is not enough, then you have some slop and / or friction in all of the rod guides

With a boom mounted servo with a carbon tube pushrod you have absolutely zero slop or flex between the servo and the tail crank.

If you think about it the tail rotor is rotating at something around 9,000rpm in idle up and when you suddenly put a few degrees of pitch on the blades, the heli will rotate but remembering Mr. Newton, the tail pitch slider will also have an equal force pushing on it. That force is directed straight into the servo linkage and any slop or flexing is putting more workload on the gyro and servo.

My first Raptor was gradually upgraded as I was improving my flying so I really didn't notice the difference. It was only when I built up the second one and flew it back to back that I noticed how much difference there is.

Maybe I'm wrong, but that's my practical experience and my theory as to why it is different. Maybe with a different gyro / servo combination you might see different results. But like I said, I was testing apples against apples with back to back flights and the difference WAS noticeable.

I guess it doesn't matter much where the rudder servo is.... But wouldn't the oil from the exhaust eventually seep into the servo thus ruining it?!

Some people say that in theory but in practise I wouldn't necessarily agree. I think it depends on the servo specs. On an S9254 the seals seem to do an excellent job of keeping oil out. I know this because I replaced some stripped gears after nearly a year on the boom. Inside there was only the original grease. No trace of fuel residue at all.

You can reduce your mess an awful lot by using a silicon muffler deflector - also takes the edge off the noise a little.

[mcgartlin]

where did you obtain the push rod for the rear mount servo.

[pvande]

I got mine from century - www.heli-world.com (http://www.heli-world.com)

Make sure to super glue the ball links that screw into the end of the rod - one of my vibrated loose yesterday and it got my heart rate up until i managed to hit the heading hold...

[Jopa]

O yah !! Archiebald speaks the truth…. Sense I have moved my rudder servo to the boom it has been quiet an improvement. Also the carbon push road has no flex or bind to it and does not require you to have to make bends in it ----- what is up with that---- I played for quiet some time to get the push road bent and with out bind using the stock setup and never did get it completely moving freely. Also,,, I used an old servo ( dead ) in the servo block to account for the CG when moving the rudder servo to boom.

Jopa…