Aerobatics vs Gyros

[tomcostanza]

I read a Mid-Continent manual that advised turning off the gyro 5 minutes before doing aerobatics. I assume the 5 minutes is to let the gyro spin down. I have 3 gyros. I don't want to use 3 switches, but I'm willing to use one 3 pole switch. Any suggestions? Has anyone done this?

Best holiday wishes to all.

[jbagley]

I'm interested in any responses to this one.

I have a vacuum attitude indicator, vacuum DG and an electric turn and bank. The turn and bank can be turned off by a switch. I assume the vacuum gyros can be turned off somehow as well, but i'm not sure how. If your gyros are all electric, I would think a 3-pole switch would work just fine (check the current draw of the instruments vs switch capacity).

Rolls don't seem to bother the gyros much, but loops make the attitude indicator unhappy. YMMV.

[flyinga]

Something to think about: a three poll swtch introduces a single point of failure for all three gyros.

[aerhed]

On an 8 I built, I installed a 3/4" ball valve to cut the vacuum off. Its on the subpanel with an easy to reach lever.

[jbagley]

Originally Posted by flyinga

Something to think about: a three poll swtch introduces a single point of failure for all three gyros.

Good point. You could use some relays combined with a switch. If the relays are normally closed circuits with a switch to turn them off then you can have a single switch without a single point of failure.

The failure mode would be in the on position.

Though everyone has to find their own comfortable balance between simplicity and redundancy. It's generally, but not always, a trade-off.

[jbagley]

Originally Posted by aerhed

On an 8 I built, I installed a 3/4" ball valve to cut the vacuum off. Its on the subpanel with an easy to reach lever.

Thought about doing that, but I'm not sure if the back-pressure would damage the vacuum pump.

[aerhed]

It makes all the air go through the regulator. An alternative would be a 3 port valve with an inlet filter. Probably more better.