16mm or 18mm servo arms

[Mark17]

The build instructions call for 16mm holes in all 4 arms. Will it cause any geomitry issues if I was to use 18mm metal servo arms?

How big of a deal is 2mms

[EEngineer]

Originally Posted by Mark17

The build instructions call for 16mm holes in all 4 arms. Will it cause any geomitry issues if I was to use 18mm metal servo arms?

How big of a deal is 2mms

On my 600SXs, the manual called for 16mm for the swash and 14-16mm on the tail.

On my 700XX, the manual called for 16mm everywhere.

On my 800XX, the manual called for 16mm everywhere.

16mm was good for the 600SX.

On my 700XX & 800XX, I am using the MKS X8 servos for the swash and tail. And their output shaft diameter requires the use of X8 arms....which have threaded holes at 18mm and 21mm.....

So, I went with 18mm...and everythings fine.

It could be a manual typo....or a starting point suggestion....

I used turnbuckles so I could tune the head "just so"....but there's a lot of factors....

Catching the closest spline that gives 90 deg. arm orientation....
Depending upon your choice of servos, the output shaft center to its bolt holes can differ by > 1mm.
FBL controller characteristics.....etc

FWIW

[Jays200]

shorter arms, as per the manuals, give higher resolution and greater torque.

[Mark17]

Cool. I'll be using the x8s as well and probably the red 2 piece arms. I would guess these x8s will have enough grunt to push the extra 2mm.

Turn buckles sound like a pretty good idea as well.

Thanks

[EEngineer]

Originally Posted by Mark17

Cool. I'll be using the x8s as well and probably the red 2 piece arms. I would guess these x8s will have enough grunt to push the extra 2mm.

Turn buckles sound like a pretty good idea as well.

Thanks

Have the red-anodized X8 arms as well...the X8's can lift a bowling ball with their torque output at 8V.

Lundsford Racing has "drop-in" M3 turnbuckles for the 800XX....get a TB wrench, too.

The 800XX link ends have a small hole below where the ball fits....I insert a small jeweler's screwdriver to use as a fulcrum, when I turn the TB wrench...or visa versa when dialing in the TB's.

You'll be amazed how much easier is is to adjust the swash and how much more precise your head setup will be.

FWIW

[Mark17]

So did you order the 3mm punisher turnbuckles x in length for the cyclics and blade grips?

Also, I guess you would have had to use the logo ball links to match the swash balls

[EEngineer]

Yes, the 3mm "Punishers"....and used the Mikado link ends

[Mark17]

Great. Thanks man