[rlricks]

There has been a lot of discussion about the strong springs on the throttles and some concern about them. I have just started flying RV-12 N522CR. My concern is not about the springs but what happens if only one of the cables becomes detached and one half of the engine goes to full while the other half is less than that what happens to the engine. I can imagine that the engine would not like it. To allay my concern I installed some cable stops to prevent the possibility of any detachment from occurring.

 

[Mich48041]

what happens if only one of the cables becomes detached and one half of the engine goes to full while the other half is less than that

I heard a rumor that the engine will run so rough that the pilot will seriously consider shutting the engine off.
An option might be to push the throttle all of the way in so that both throttles will be wide open.
Joe Gores

 

[Mark Henderson]

Several of us in the San Francisco area attended a Rotax course taught by a very experienced Rotax mechanic who just moved here from England. He had experience with a single cable breaking. If you were at cruise power and one broke, it will not be a major deal. If you were at a low power setting and one broke, you will have serious vibration. It's not like a mag failure where all cylinders are still getting spark and equal fuel.Two cylinders will be at max power and the oposite two might be at idle. Rotax has us balance the carbs for a reason.

 

[Bruce Russell]

Cable stops are a good idea. I would also recommend replacing the supplied nyloc nuts with the mechanical style locking nuts. My nyloc's backed off in flight and I experienced the situation you are concerned about. The engine runs VERY rough at anything other than WOT. My solution was to get within gliding distance of the airport at WOT and shutdown the ignition. It was impossible to descend without redlining the airspeed, but a little extra altitude when that prop stops turning is not unwelcome. Double and triple check those cables!

 

[rgmwa]

To allay my concern I installed some cable stops to prevent the possibility of any detachment from occurring.

Sounds like a good idea. Do you have any photos of your setup?

 

[rlricks]

Sounds like a good idea. Do you have any photos of your setup?

I used somewhat of a jury rig. I had on hand some electrical solderless lugs. I sawed off the projecting part and simply slipped the lug onto the cable behind the throttle linkage but any sort of cable stop will do the job.

 

[BigJohn]

Confused .......

... about where these stops would go. Can somebody post a better explanation or a photo?

 

[Mich48041]

Throttle cable stop

John,
I have not installed these stops but assume that they go on the most forward part of the throttle cable that protrudes forward past the carburetor throttle arm. After the cable has been cut and the end is splayed, it might be difficult to get all of the strands back together in order to slide a stop on.
Joe Gores