Turn Coordinator RC Allen Maintenance

[AlexPeterson]

Greetings,

Has anyone repaired one of these themselves? After almost 1000 hours, the bearings are howling. Can parts be procured by non-repair shops, i.e., me? I can't imagine it would be too difficult.

It is a model RCA-82A-11.

Thanks!

[Dave62]

Alax,
I have been in more than one gyro horizon. Bearings are fairly easy to replace...however everything is balanced and you must remove some of the balance weghts and adjustments to get to the rotor bearings. ...
This in my openion makes it a shop only repair.
Dave (Swift Driver)

[AlexPeterson]

Dave, thanks. Is this balance you describe applicable to a turn coordinator? I can imagine gimbal sets in an A/H needing to be balanced.

[Bob Axsom]

My attitude indicator in my RV-6A actually failed a few weeks ago for the second time in 410 hours. The first time was what I consider a legitimate failure from buying the instrument early to make up the instrument panel then leaving it set it the exact same positiong for years while I finished the plane and then flew it for a couple of hundred hours. This last one happened not too long after I had a vacuum pump failure with no blowback protection in-line filter between the pump and the instruments. I drove down to Rudy Arkansas on Friday afternoon and I was called on Monday to come pick it up. Mike at Rudy Aircraft Instruments told me that the rotor was badly contaminated with debries from the pump failure and he replaced the bearings, serviced, tested and certified the instrument.

I know from your posts that you are a very talented person and I have little doubt that you can accomplish the replacement of the bearings. It, no doubt would be a very educational exercise. Just one precaution, I do not think the repared instrument would be legal for instrument flight and it would probably at least require placarding against it but I'm not prepared to defend that position. Some talk about the FARs sounds as if they fit in one nice little book but that is not the case. During a short period as Manager of Systems Operations and System Support at Douglas Aircraft in Long Beach the Technical Library was one of the organizations I was responsible for. The FARs were a significant update responsibility for the two people working there and these not unambiguous documents occupied a very large section of the library.

Bob Axsom

[AlexPeterson]

Originally Posted by Bob Axsom

My attitude indicator in my RV-6A actually failed a few weeks ago for the second time in 410 hours. The first time was what I consider a legitimate failure from buying the instrument early to make up the instrument panel then leaving it set it the exact same positiong for years while I finished the plane and then flew it for a couple of hundred hours. This last one happened not too long after I had a vacuum pump failure with no blowback protection in-line filter between the pump and the instruments. I drove down to Rudy Arkansas on Friday afternoon and I was called on Monday to come pick it up. Mike at Rudy Aircraft Instruments told me that the rotor was badly contaminated with debries from the pump failure and he replaced the bearings, serviced, tested and certified the instrument.

I know from your posts that you are a very talented person and I have little doubt that you can accomplish the replacement of the bearings. It, no doubt would be a very educational exercise. Just one precaution, I do not think the repared instrument would be legal for instrument flight and it would probably at least require placarding against it but I'm not prepared to defend that position. Some talk about the FARs sounds as if they fit in one nice little book but that is not the case. During a short period as Manager of Systems Operations and System Support at Douglas Aircraft in Long Beach the Technical Library was one of the organizations I was responsible for. The FARs were a significant update responsibility for the two people working there and these not unambiguous documents occupied a very large section of the library.

Bob Axsom

Bob, thanks for the largely undeserved compliment - I'll take them any way I can!

I'm still trying to find those with experience dissecting a turn coordinator - which is a much simpler instrument than an attitude gyro.

As to any connections between who repairs a gyro and legalities for instrument flight in an experimental - I don't believe that applies to experimentals (there may be valid practical concerns). However, I'll leave that to others to discuss.

[CESSNADON]

There are many variations of T&B's and TC's. Disassembly is pretty straightforward although there "tricks of the trade" to getting some of the components apart. The most difficult part of the EGC TC is getting the damping correct. It is done by adjusting the amount of a very viscous silicone oil between the pointer shaft and a cup. Without the overhaul manual and a rate table you would not be able to sucessfully return the instrument to useful service

[AlexPeterson]

Originally Posted by CESSNADON

There are many variations of T&B's and TC's. Disassembly is pretty straightforward although there "tricks of the trade" to getting some of the components apart. The most difficult part of the EGC TC is getting the damping correct. It is done by adjusting the amount of a very viscous silicone oil between the pointer shaft and a cup. Without the overhaul manual and a rate table you would not be able to sucessfully return the instrument to useful service

Thanks, that is just the type of info I needed! Let's see, now on to building that rate table...