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View Full Version : Metal Servo Arms: Good or Bad?


dunkonu23
09-29-2011, 05:08 PM
I'm sorry but I don't think having metal servo arms is a good thing with this helicopter. Metal arms on larger helicopters with metal servo cases in an FBL situation is great if you're a pro, but on a smaller helicopter with plastic servo cases I think it's overkill and is asking for trouble. Trouble in the form of destroyed servos in the event of a hard crash (or maybe even a light crash if it's hit right) where a plastic servo arm would normally break. Overkill in that the torque needed to move the head isn't as great as with a larger helicopter and I sincerely doubt the standard arms would flex at all during hard moves.

What do you think?

The rest of the helicopter looks cool, especially the drive train. I may be getting that gear set for my ESP. It's also cool the way Align has taken into account elevator arm touching the tail drive gearbox and antirotation braket at the extremes.

It's just my opinion.

Scott

akamullen
09-29-2011, 06:12 PM
IMO before you would strip the gears on a metal gear servo the plastic ball links would go . I have metal arms on all my birds that they fit on and have broken many plastic ball links but never stripped gears or wrecked a servo due to a metal arm in a crash.

hndaluvr
09-30-2011, 08:02 AM
I've actually witnessed all 3 situations happen... plastic arms breaking, ball link breaking, and gears mangling. I kind of agree that plastic arms are a safer option, considering that a new gear set is ~$25... each:wow2:
I have a new 500EFL, and while the metal arms look real nice, they are real PITA to get on/off, and i fear destroying a servo upon any unfortunate encounter with the ground.
I just ordered the a plastic set, and will use those until i determine whether ANY arm makes a difference in crash-ability.

rotaryguy
09-30-2011, 08:18 AM
I created a thread on this. How to easily remove aluminum servo arms-
http://www.helifreak.com/showthread.php?t=342424

dunkonu23
09-30-2011, 11:44 AM
That's a really cool solution for removing the arm. :)

I've been the brunt of the worse end of the spectrum when using a metal arm. I had two servos on my first helicopter get completely destroyed. I'm talking plastic case ripped to shreds, gears broken, circuit board broken, and I never found the motor from the servos... all due to a blade ejection. I haven't used metal arms since.

Scott

hndaluvr
09-30-2011, 12:48 PM
I created a thread on this. How to easily remove aluminum servo arms-
http://www.helifreak.com/showthread.php?t=342424


Brilliant!.... will do... uhhhh, but this means that i'll have to curse one more time while taking 'em off to do the mod :rotf

Shawn Behrens
09-30-2011, 02:21 PM
I completely agree that on this size machine metal arms are a terrible idea (atleast from the consumer standpoint). The metal arms are pure bling and another way for align to make more money selling gear sets for the servos. I am using the + shaped arms on my 500 pro and by using those arms I am actually getting a better fbl setup by gaining better resolution from the actual servo ( vs playing with geometry mechanically above the swash by changing out balls). I don't believe that running plastic arms on the 500 pro will save your servo gear sets in every crash but it will give them a fighting chance. On larger 90 size machines I run metal servo horns out of necessity, the plastic sero horns will jump splines on the output gear due to much much higher loads placed upon the servo. Keep in mind the output spline on these 1 oz ds510 servos is the same as the output spline on the full-size 2 oz ds610 servos.

shawn

Stevin
10-02-2011, 04:41 AM
I think the reason metal servo arms are ow being offered with stock fbl kits is they are more rigid and the flybarless system needs to constintely make adjustments to itself. The metal arms will make those exact without flex. Maybe not as crucial on this size bird but anything bigger yes.

dunkonu23
10-02-2011, 11:37 AM
Here's a little tidbit that you may find interesting. Metal arms are not currently included with the 550 V2 FBL kit. I'm helping a friend build a 550 V2 FBL. He was one of the first to get one, though. Maybe in later kits, but not in his.

Scott

SimStream
10-02-2011, 12:10 PM
Metal arms appeared on the 600 pro and are needed because the attached ball link is long and stands away from the arm, so the arm is subject to twisting. They are not needed on a heli where the ball link is standard and can be considered 'bling'

akamullen
10-03-2011, 12:03 AM
Metal arms appeared on the 600 pro and are needed because the attached ball link is long and stands away from the arm, so the arm is subject to twisting. They are not needed on a heli where the ball link is standard and can be considered 'bling'
Exactly, but on 90 size FBL machines they are needed. I have seen the plastics strip in flight on the spline. Although this will most likely only happen during hard 3D flying and only on FBL machines.

SimStream
10-03-2011, 10:30 AM
Exactly, but on 90 size FBL machines they are needed. I have seen the plastics strip in flight on the spline. Although this will most likely only happen during hard 3D flying and only on FBL machines.

True