Gyros in a Citabria--disable or remove?

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lonzo1961

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Hello all. I am a fairly new pilot and a newer Citabria owner. I bought this plane to fly Xcountry and do light aerobatics. After taking a ten hour course (Decathlon) and getting signed off to do them in this plane, the problem I have now is: what to do with the gyros. This plane came with a full six pack on the panel, and I am already seeing the AH do weird things. I have heard of some pilot-owners installing bypass valves on the vacuum line in order to disable the gyros pior to aerobatic flight. I ran this idea by the A&P, but he wants a parts kit and the paperwork required to do this prior to proceeding. I said I would look into it and get back to him. So far, I have found little online that is of help. Once I found this forum, I figured I would throw it out there. Should I install a bypass of some sort, or simply remove the vacuum pump and the AH and DG? I hate to lose the gyros, but I really do not necessarily need them, since I am VFR only anyway. Please advise.
 
I believe that, if you simply cut off the vacuum to the gyros, you'd expose them to greater likelihood of damage during maneuvers.

Is your principal concern that you have gyros which are not certified for use in aerobatic flight, or simply that the attitude indicator is showing signs of trouble?

It might not hurt if you told us more about how the aircraft is equipped (ie, models of instruments, etc.), and then, people who are well-equipped to answer your question (meaning, people other than me!) can chime in.

And, by the way, welcome to PoA!
 
lonzo1961 said:
Hello all. I am a fairly new pilot and a newer Citabria owner. I bought this plane to fly Xcountry and do light aerobatics. After taking a ten hour course (Decathlon) and getting signed off to do them in this plane, the problem I have now is: what to do with the gyros. This plane came with a full six pack on the panel, and I am already seeing the AH do weird things. I have heard of some pilot-owners installing bypass valves on the vacuum line in order to disable the gyros pior to aerobatic flight. I ran this idea by the A&P, but he wants a parts kit and the paperwork required to do this prior to proceeding. I said I would look into it and get back to him. So far, I have found little online that is of help. Once I found this forum, I figured I would throw it out there. Should I install a bypass of some sort, or simply remove the vacuum pump and the AH and DG? I hate to lose the gyros, but I really do not necessarily need them, since I am VFR only anyway. Please advise.
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Call American Champion ((262) 534-6315) and ask for the technical guys who can answer that. Have your serial number handy. Or check your peperwork for the equipment list (should be with the weight and balance info) for the gyros to see if they're required or optional.

Dan
 
Having sold my Mooney and acquired a Waco YMF-5C, I am going to ask the same basic question.

What is the best way to protect gyros never intended for acro? I have an electric AH, Electric slaved HSI and of course the T&B. Since I intend to fly X-ctry and even occasionally "easy" IMC/IFR I would like the Gyros to stay healthy. I don't propose to do a lot of acro but I do want to do the occasional positive G maneuver. I've thought about a sleeve to hold the caging knob (AH) out during any "maneuvering flight" and/or pulling the breakers. If only the glass panels were free
 
Greg Bockelman said:
Why? :confused:
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My understanding is that a powered gyroscopic instrument (whether pneumatic or electric) works AGAINST being moved out of center and against it's own mass being pushed to the internal stops during acro.

Shut whatever powers the gyro off and you have the weight of the gyro motor(s) slamming up-down-left-right in the gimbels and against the stops with absolutly no cushioning.

Look inside a DG or AH sometime; the motor spindles and bearings are tiny!

Acro may side load the bearings and cause premature bearing failure in a powered gyro but (IMPO) shutting off the power and flying acro is a recipe for flat-spotted bearing and bent gyro spindles...

From my discussions with acro pilots around here the consenses is that "Gentlemans Acro", loops, rolls etc. is not nearly as hard in instruments as really abrupt changes in direction/ velocity like snaps, tumbles and stuff like that.

Again, JMPO.

Chris
 
Concur with the above -- either replace with cageable gyros (best choice), remove them for acro flight and reinstall for normal flight (requires A&P's signature each time), or just leave them running (modern gyros are more resistant to this abuse than the older ones). Installing a vacuum cutoff switch is not an option the FAA will approve (they went through this over partial panel instrument training years ago), and disconnecting/disabling (with placards) results in more damage than leaving them running.
 
Hiperbiper said:
My understanding is that a powered gyroscopic instrument (whether pneumatic or electric) works AGAINST being moved out of center and against it's own mass being pushed to the internal stops during acro.

Shut whatever powers the gyro off and you have the weight of the gyro motor(s) slamming up-down-left-right in the gimbels and against the stops with absolutly no cushioning.

Look inside a DG or AH sometime; the motor spindles and bearings are tiny!

Acro may side load the bearings and cause premature bearing failure in a powered gyro but (IMPO) shutting off the power and flying acro is a recipe for flat-spotted bearing and bent gyro spindles...

From my discussions with acro pilots around here the consenses is that "Gentlemans Acro", loops, rolls etc. is not nearly as hard in instruments as really abrupt changes in direction/ velocity like snaps, tumbles and stuff like that.

Again, JMPO.

Chris
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AFaIK many gyros (some AIs, most DGs, and all T&B/TCs) are quite happy operating through 360 degrees of roll, bank, or yaw. IOW, it's quite likely that the only gyro you need to be concerned with is the AI.
 
Or replace the AI and HI with the Aspen solid-state stuff. No moving parts at all. And probably as expensive as the rest of the airplane...

Dan
 
I'd fly the things until they break, and then replace them with solid state. Or don't replace them at all, who needs gyros for VFR flight? They certainly won't keep up with acro.
 
steingar said:
... who needs gyros for VFR flight? ...
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I would like to be able to fly some (easy) IFR when I get comfortable with the airplane, and I would just as soon have the gyros in good shape when I do. I suspect an occasional loop won't hurt much, but if there is a way to protect the gyros I would like to do so.

Ernie
 
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