Manufacturers find that as long as running gyros are free or uncaged during these manoeuvres, aerobatics, berlin doner, and the g-loads associated with them have little to no impact on the lifespan of running gyros. Locking the gyros in a caged position during these motions may injure the spin bearings and/or gimbal bearings because of the large angular momentum of the spinning mass and the resulting quadrature stresses. During aerobatic manoeuvres, the gyro should be caged; for level flight, it should be caged again.
Aerobatics and a gyroscope
A directional gyro’s caging feature can be used to quickly lift the rotor onto a horizontal plane and align it with the magnetic compass. When doing aerobatic manoeuvres, if a spinning heading card is encountered, the pilot can stop the rotation of the card by pushing the caging knob. Align the heading card with the compass needle after pulling the caging knob to get the plane flying straight and level once more.
If they don’t have a caging mechanism, the majority of horizontal aerobatics gyros will have a pitch range of about +/-85 degrees and a complete 360 degrees of roll. Due to regulated precession, the accurate pitch and roll information is preserved even after full revolutions. The Horizon Gyro can be counted on to remain upright (with its spin axis aligned to the dynamic vertical) and provide precise pitch and roll references for the great majority of aerobatic manoeuvres. However, if you carry out any of the following manoeuvres, the Horizon Gyro could “spin out”. The main disadvantage is that, during 10–20 minutes of level flight, the Horizon Gyro may not be fully developed and provide correct pitch and roll data.The pilot merely needs to pull the caging knob in order to realign the gyro rotor with a vertical reference and resume level flight if the Horizon Gyro rolls when performing aerobatics (*using the horizon of the Earth as a reference). The pilot would still have access to relevant pitch and roll information, and the tiny inaccuracy would be corrected by the internal erecting system in 2 or 3 minutes, depending on how successfully the pilot matches his aircraft with level flight throughout the caging procedure.
*Except while using visual flight rules when the horizon is clearly visible, aerobatic manoeuvres are forbidden.
In A Nutshell
Hello, Jerry Bishop is a private pilot who also fixes vintage aerobatics. I have 45 years of experience designing aviation instrumentation (gyros, vacuum pumps, and engine instruments). Visit Pilot One for a while, then proceed to Jerry’s Hangar for more information, pictures, and stories about flying. I like to study online articles on aviation to increase my understanding.
