Brittain TC100 - gyro lock?

[Mobius708]

Hello all, I have 2 things regarding the TC. On a recent flight I was messing with roll trim and it seemed some combination of twisting and pushing the stem lead to the TC not deflecting anymore. I confirmed it was erroneous as enabling the PC commanded a wing over, fun.

 

There was no deflection on it for the rest of the 2 hour flight. I went up again later after messing with it again on the ground and all indications and PC behavior returned to normal. Yesterday was a 4.5 hour round trip and all was well.

 

Is this a known function of the TC100? A type of failure mode? It's been real difficult to find information on some of these older systems.

 

Also, how much work is it for an avionics tech to access that front panel of the instrument? For whatever reason my ball is entirely black on black and neigh impossible to see in anything but broad daylight, so I was hoping to paint it or something.

 

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[N201MKTurbo]

It has been decades since I took one apart, so my memory may be a little fuzzy. The valve consists of a vane on a pivot with two spring pins. The spring pins are pushed back and forth by a pin on the gyro gimbal shaft. The movement of that pin is the same as the little airplane on the front. The spring pins on the vane are there so if the vane gets stuck, it won’t stop the little airplane on the front from moving. The same spring pins are on the little airplane on the front of the gimbal shaft.

There is a movable orifice plate between the vane and the hose barb block. The knob is connected to that orifice plate with a speedometer cable flexible shaft. It is possible if you were pushing or pulling on the knob that you moved the orifice plate so it jammed against the vane and stopped it from moving. The knob wasn’t meant to be pushed and pulled.

[Mobius708]

It has been decades since I took one apart, so my memory may be a little fuzzy. The valve consists of a vane on a pivot with two spring pins. The spring pins are pushed back and forth by a pin on the gyro gimbal shaft. The movement of that pin is the same as the little airplane on the front. The spring pins on the vane are there so if the vane gets stuck, it won’t stop the little airplane on the front from moving. The same spring pins are on the little airplane on the front of the gimbal shaft.
There is a movable orifice plate between the vane and the hose barb block. The knob is connected to that orifice plate with a speedometer cable flexible shaft. It is possible if you were pushing or pulling on the knob that you moved the orifice plate so it jammed against the vane and stopped it from moving. The knob wasn’t meant to be pushed and pulled.

That is great to know, thank you

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[DCarlton]

3 hours ago, Mobius708 said:

That is great to know, thank you

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Just FYI, if you continue to have issues, I sent my TC100EVT to Kevin Westbrook (former Brittain tech) in Tulsa for repair during my last annual.  He's still available to help.  It's definitely a gentle twist knob, not a push and twist knob.  

[Mobius708]

Just FYI, if you continue to have issues, I sent my TC100EVT to Kevin Westbrook (former Brittain tech) in Tulsa for repair during my last annual.  He's still available to help.  It's definitely a gentle twist knob, not a push and twist knob.  

Oh yeah, I've spoken to Kevin quite a bit before. Not too far from Tulsa nowadays.

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