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Cable Rattle during Vx Climb Out

jrock836

Well Known Member
Shortly after buying my plane I had an incident that definitely got my attention. During climb out I had a very loud rattle/metallic slapping noise coming from behind me. It was loud enough that it broke the intercom squelch and could be heard through the headsets. It was unnerving and made me pull back the throttle and start looking around to see if I had left something hanging outside the canopy that was slapping on the fuselage in the wind. I didn't find anything unusual and finally concluded that I likely have a control cable that is a little loose and probably hitting something (tailcone ribs?) during aggressive climb outs.

I'm in the middle of a Condition Inspection right now and decided that I want to go through the Cable Tension procedures listed in Chapter 6 of the RV12 Maintenance Manual. My questions are as follows:

1. The MM says cable tension can very greatly due OAT. The colder it is, the looser cable tension will be. Is cable rattle a common thing, when it's cold outside? It obviously has been winter and it was cold (40-50 degrees) when I heard the noise.

2. I'm trying to visualize what Step #9 wants me to do. "Secure the control stick in place using a spring clamp to attach it to a 41" long stick bridged between and clamped to the upper longerons." Anyone have a photo? Can anyone help me to understand this step.. Maybe it will be more clear once I get everything opened up?

3. Anyone who has gone through the procedures listed in Chapter 6, any words of wisdom or advice to make the job easier? I feel like the job is probably a pretty simple deal, but putting everything down on paper makes it sound more complicated than it really is..
 
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Shortly after buying my plane I had an incident that definitely got my attention. During climb out I had a very loud rattle/metallic slapping noise coming from behind me. It was loud enough that it broke the intercom squelch and could be heard through the headsets. It was unnerving and made me pull back the throttle and start looking around to see if I had left something hanging outside the canopy that was slapping on the fuselage in the wind. I didn't find anything unusual and finally concluded that I likely have a control cable that is a little loose and probably hitting something (tailcone ribs?) during aggressive climb outs.

I'm in the middle of a Condition Inspection right now and decided that I want to go through the Cable Tension procedures listed in Chapter 6 of the RV12 Maintenance Manual. My questions are as follows:

1. The MM says cable tension can very greatly due OAT. The colder it is, the looser cable tension will be. Is cable rattle a common thing, when it's cold outside? It obviously has been winter and it was cold (40-50 degrees) when I heard the noise.

2. I'm trying to visualize what Step #9 wants me to do. "Secure the control stick in place using a spring clamp to attach it to a 41" long stick bridged between and clamped to the upper longerons." Anyone have a photo? Can anyone help me to understand this step.. Maybe it will be more clear once I get everything opened up?

3. Anyone who has gone through the procedures listed in Chapter 6, any words of wisdom or advice to make the job easier? I feel like the job is probably a pretty simple deal, but putting everything down on paper makes it sound more complicated than it really is..

#2

The goal is to lock the control stick in the pitch neutral position.
The suggested method is to clamp a 41" long stick laterally across the cockpit and then clamp the control stick to the lateral stick.

Be sure that the right side seat pans is full screwed in place as well or it will cause an incorrect result.
 
Check the rubber fairing strip between the wing root and fuselage. They can pop out of place and if they do, they will slap the sides of your fuselage and make a lot of scary noises.
Ask me how I know.
 
Also, the cable system for the rudder does not have any tension or return springs -- the pilot's feet on the rudder pedals keeps the cables sufficiently taut. It could be that if the pilot's feet are not pressing on the rudder pedals the loose rudder cables might flop around a bit creating the noise you are hearing.

ps -- I would first check the stabilator cable tension per the MM.
 
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