Throttle return spring

[tauscnc]

I finally have it on. Took all of 5 min and will save me the chicken dance I hope.

On my last crash where my hub broke in flight when it hit the battery lead pulled out...luckily it was at idle.

Spring from Ace Hardware.

[jczankl]

Nice! I like it!

[dodgeboy]

just a thought, wouldnt it be better on the carb horn rather than the servo arm ? what if the servo horn breaks and the rod comes off ?

[tauscnc]

Originally Posted by dodgeboy

just a thought, wouldnt it be better on the carb horn rather than the servo arm ? what if the servo horn breaks and the rod comes off ?

True true. It would take those two issues out also.

[SMJT]

Hopefully this will do for the time being but would like to see pictures of other solutions.

[Flydynamics]

Years ago in France when I was competing in F3A pattern plane I've installed a torsion spring on the carburetor and was using a Kevlar wire between throttle servo and carburetor horn to control the carburetor, very precise as no play at all in the control.
Sadly the system in picture will not prevent a chicken dance unless the servo strip his gears or I'm assuming the spring can move the servo horn when the servo is powered, in this case that should work but I doubt that is possible with servo powered.
Not willing to be negative or whatever, just trying to help.

[u8at711]

I had a bad flight pack battery connection, the power reset while the HELI was in the air, the tail gyro rebooted, the HELI then started to piro out of control, I hit TH, nothing happened,
Was able to set the machine down in some bushes, great maiden flight
Did not take long until the motor's clutch and bell exploded, the motor screamed until it ate so much clutch liner that it stalled.

Cause of the throttle being stuck wide open was the carbs barrel control arm got loose, so the only thing that would have closed that throttle barrel would have been a shaft or pin going threw that carb barrels hole, to a return spring or something.
I was using a servo arm and not the proper carb control arm, stupid mistake cost me almost $400. I'm not going to hook up a return spring on my stuff, but figured you could learn from my misfortune.

To bad there is no small control valve to cut fuel supply in this event,

[SMJT]

I am not sure what you mean shotgun34 by servo gears need to strip because for the system to work the servo needs to unpowered but if you still have power you hit throttle cut.

The chicken dance isn't the main reason I am worried.
Here is a scenario say my power switch becomes dodgy and I don't realize, flying around having fun then it fails... no power to the electronics so no receiver failsafe throttle still open positive collective, BYE BYE NX4 as it flies away in the distant.

It is very unlikely to happen but it can happen

[1BADAIR]

yep. return springs work great if the battery is dead or disconnected. Watched a 700 eject a battery. Almost no damage cause the engine shut off immediately.
GMK also makes bands called Carb O's that work great also

[Flydynamics]

SMJT, the case you are describing will effectively work for the systems shown in pictures on this thread.
A good inspection before flight might help but once again we will not be able to find a solution to every scenarios possible.

u8at711, I'm so sorry for you, hopefully you'll be able to keep going in some time .... I don't understand why the Rx didn't reboot properly and sent to the throttle servo the information for idle position.
What Rx / Tx are you using ?

[u8at711]

using the 14sg, this was not my nx4, but a trex700 with flybar.
the throttle linkage horn on the carb got loose during the flight, thats what caused the throttle issue.
most of the cost damage was having to rebuild the motor. did not even bend the flybar
bad parts, boom, tail blades, clutch, clutch bell, liner, and rebuild motor. new battery connector for the electronics. a few bushes were trimmed LOL

[Flydynamics]

I bet it worked very well to trim bushes ;-)