friz

My Feedback: (2)

I am new to gas, so this may seem like a silly question to you all. When rigging the throttle on my first glow airplane H9 twist, I was amazed at how easy it was to actuate the throttle but a full sized servo cutout was in the throttle position. Another thing suprised me. All of the servos on this palne are very close to the control surfaces, but the throttle servo is buried in the middle of the fuse. Wouldn't it make more sense to put a micro servo right next to the engine and actuate the throttle with a little push rod.

frank99

My Feedback: (29)

you got it right frank

jetmech05

seems to me that a micro servo might be affected by the vibration of the engine...

da Rock

If that is a concern (and it should be with some little servos) then look at the Hitec hs-225. It's called the Mighty Mini. It's not a micro, but is less than an ounce. And it has the torque of a standard servo. And it's only around $20.

da Rock

It certainly would if the environment around an engine was a bit nicer.

Most servos are surprisingly hot fuel proof. But some aren't. And the vibration around the engine and firewall is quite different than the vibration felt through a servo cutout back in the fuselage.

So most designs consider the best location for the majority of modelers and take the safest way out. Just like they do when suggesting the CG location.

friz

My Feedback: (2)

Thanks for the explanation.

Don41

Use a standard servo (but use the cheap one). You may need to access the servo at some point in time so leave it mounted where you can get to it without operating on your fuselage. A standard size but cheap analog servo such as the Hitec 422 is only $12.50 at Tower.

da Rock

You know, the Twist uses aileron servos out in the wing doesn't it.

You save over half an ounce every time you use an Hitec HS225 instead of the average servo. So if you used 3 HS225s in either the 40 or the 60 size Twist, you'd save probably about 2 ounces (most standards are closer to 2 ounces than 1.5 ounce). It's worth doing.

BTW, a lot of micro's really don't have enough torque to handle the throttle chores if the pushrod binds at all. I've found the Hitec HS-81 with about 36oz/in torque (about $16 ea) to be about the low range for torque that'll work the throttle ok.

friz

My Feedback: (2)

I thought about using HS 81's all the way around on the twist. I have used them on large wings with huge surfaces with no problems. I was thinking of more like an HS 55 on the throttle.

jeffk464

Was just looking at servos on tower hobbies site and it looks like Hitec just released a new servo HS-82HD or 82MG.

BillS

I use older standard servos for throttle mounted at least 12 inches away from the engine and connect with nyrod. Don't like to put electronic gear anywhere near the engine.

Bill