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View Full Version : HS 65 servo's on pro - which output arm/position are you using ??


jamesb72
07-19-2009, 08:42 AM
I've fitted HS65 servo's and had some trouble with selecting output arms.

First try, I chose the tougher single output arm, and 3rd hole out from centre (16.5mm) - however the elevator servo runs so close to the swash guide bracket the ball link rubs ! Next hole in is only 13.5mm which I figure won't give enough travel.

I switched to the thinner 180deg arms, and realigned them to pick the best side for 90deg at servo centre, the 4th hole out is approx 15.5mm, which just clears the swash guide mount with ball link fitted, however I am worried if these servo arms are sufficiently rigid.

I test flew, and smooth hovering is fine, but if I 'flick' the cyclic, the heli starts to oscillate gently in a wobble board fashion - I cannot see there is any flex/slop anywhere else in the head, so I think this is resonance in the servo arms ??

Which output arms have people used without probs, will the thicker arm 2nd hole out enough travel ?? I have swash mix pitch 60% with 70% for ail and elevator, so presume I could increase the swash mix to make up for shorter output arm ??

Shawn Behrens
07-19-2009, 01:25 PM
Use the 2nd hole out on the thicker arms (it's what I did) and just turn up your swash values till you are happy with the results. Funny thing is the geometry on the swash is not ideal with the supplied align servo arms either, just take a look at the tilt on the elevator servo to swash link. The geometry improves with the ball at a shorter distance out on the servo arm (like mentioned with the hitec arms), only thing you need to do is then turn up the swash values.

I just put 5065's in my pro and it's a nice.

jamesb72
07-19-2009, 02:06 PM
Thanks - I swapped the arms to the thicker ones on 2nd hole out this afternoon.

Increased swash mix for pitch to 70% (from 60%) to get +/- 10deg which seems fine.

The aileron servo seems to run out of travel at full neg pitch, full right cyclic when you then push full forward elevator, but this is pretty unlikely to ever occur in flight - bizarrely pitch servo has plenty of travel even with full left cyclic full forward elevator ? I am using some subtrim so figure this is why.

I'm much happier with the thicker servo arms, there is no noticable flex in them at all, whereas the thinner 180deg arm would twist and flex noticably which didn't look good.

Mathias
07-19-2009, 02:15 PM
What's the recommended length from center to hole on the servo arms per the manual?

Shawn Behrens
07-19-2009, 08:12 PM
The aileron servo seems to run out of travel at full neg pitch, full right cyclic when you then push full forward elevator, but this is pretty unlikely to ever occur in flight - bizarrely pitch servo has plenty of travel even with full left cyclic full forward elevator ? I am using some subtrim so figure this is why.

I'm much happier with the thicker servo arms, there is no noticable flex in them at all, whereas the thinner 180deg arm would twist and flex noticably which didn't look good.


If you are using a dx7 (spectrum or JR) enabling the swash exp function will help to maintain cyclic travel while high collective values are being used. But you are correct that it is very unlikely to ever have the sticks in these positions while inflight.

Mathias
07-21-2009, 07:41 AM
What's the recommended length from center to hole on the servo arms per the manual?Anyone?


Thanks,

jamesb72
07-22-2009, 06:20 AM
I think the supplied DS410m servo recommended outermost hole is around 15mm from memory - I don't remember any length being given in manual - they assume your using DS410m servo arms.

mahbouni
07-23-2009, 05:31 AM
What's the recommended length from center to hole on the servo arms per the manual?Just go with the hole that gives you the best linkage geometry.

Buffaloirish
07-23-2009, 04:07 PM
3rd hole from center on the thick single Hitec arm for the aileron and pitch, second hole from center for the elevator (had to trim the other two holes off to clear the A/R bracket). That gave me PERFECT 90 on elevator and as close as I'm gonna get for the front two.

jamesb72
07-24-2009, 10:14 AM
If your using different length servo arms/positions on elevator to pitch/aileron your going to have some fun setting ATV's to avoid pitch/cyclic ineraction !

Everytime you pitch up the heli is going to rear back at you ??

Buffaloirish
07-24-2009, 10:25 AM
If your using different length servo arms/positions on elevator to pitch/aileron your going to have some fun setting ATV's to avoid pitch/cyclic ineraction !

Everytime you pitch up the heli is going to rear back at you ??

That's when I give it a beat down with the TX right?

Mathias
07-24-2009, 02:06 PM
Just go with the hole that gives you the best linkage geometry.Yea, but I'm taking the servos from my G5, and since the servo arms are cut down (only running 13mm or so), I had to ask since I may needed to order a new set of arms.

Anyways, new arms arrived today.


Thanks,

TRex888
10-25-2009, 03:00 AM
Yea, but I'm taking the servos from my G5, and since the servo arms are cut down (only running 13mm or so), I had to ask since I may needed to order a new set of arms.

Anyways, new arms arrived today.


Thanks,
Hey Mathias,

What distance did you end up using in the end? I'm in same position 13 mm with set up ffrom my G5, but I'm reading it needs to be 15-16 mm for the Pro. Kit's not here yet, but I'm thinking if I need to order new horns.

Thx.

Vinci
10-25-2009, 04:39 AM
The double arms are closest to the stock Align arms, I use the outer hole and cut one of the two arms off.

zhnme523
10-27-2009, 02:59 AM
Same as me.. Using Hite 65hb double arm; using 3rd hole from inside and have about 90deg straight to my swashplate. Putting 55% on swashplate setup in my futaba 6exh and having -12/+12 pitch each.

firefly412
10-27-2009, 06:52 AM
I used the third hole out on HS65, single thick arms, for all three servos. I had to trim off the end of the elevator arm as well as shave off the bottom support ridge of the anti-rotation bracket for the elevator arm and link to clear it. It's a close fit. Cutting/shaving off the bottom ridge of the anti-rotation bracket doesn't seem to affect the strength of the A/R bracket very much (it's left and right strength that you need anyway, not fore and aft) and that length of the arm seems to work well for me.

TRex888
10-30-2009, 06:45 AM
I used the third hole out on HS65, single thick arms, for all three servos. I had to trim off the end of the elevator arm as well as shave off the bottom support ridge of the anti-rotation bracket for the elevator arm and link to clear it. It's a close fit. Cutting/shaving off the bottom ridge of the anti-rotation bracket doesn't seem to affect the strength of the A/R bracket very much (it's left and right strength that you need anyway, not fore and aft) and that length of the arm seems to work well for me.

Thanks. I discovered this is the best way too. The distance from centre is around 16.5mm. Using the 13.5mm holes on shorter arms work, but I ended up with 100% pitch. Using the 16.5mm holes I get almost bang on 60% pitch setting for +/-12 degrees of pitch.

Note: 16.5mm set up gives a teepee setup. The 13.5mm gives a perfect straight set up, but don't be fooled by this. The servo limits needs to be mxed out to give the maximum pitch range.