Author Topic: Sperry 311 / Honeywell vg-311 gyro  (Read 821 times)

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Offline wjeTopic starter

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Sperry 311 / Honeywell vg-311 gyro
« on: December 02, 2022, 12:28:46 pm »
I'm desperately looking for at least connector pinouts for this critter. I'm really into mechanical gyros, got one of these, want to get it running. It was very popular in commercial aircraft in the late 60s and into the 70s, including the 747. One would think the info would be around, but I sure can't find any. I'm hoping to avoid hours of tracing and deciphering the electronics, such as they are (all discrete point-to-point on standoffs, all transistors, no ICs at all). One thing I know so far, takes 115v 400Hz.

Thanks, Bill
 

Offline wjeTopic starter

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Re: Sperry 311 / Honeywell vg-311 gyro
« Reply #1 on: February 18, 2023, 01:29:53 am »
Followup, found an aircraft svc company that was gracious enough to send me the complete service manual. I have it working, such a nice critter. The pitch/roll outputs are synchros. And yes 115V 400Hz, which is a bit of a pain to provide. Takes a bit over a minute to spin up (to 11K rpm) and stabilize. Has some really strange feedback sensors to correct for drift, liquid filled levels. Leads on both ends and in the middle. Each outer lead goes to a torque motor winding, counter-wound for each end. The variable resistance vs angle determines the current to the torque motor windings. No damping electronics. Not really any electronics at all. The electronics only do fault monitoring and some simple 'fast startup' control provided by inductors with shunting SCRs. On start, SCRs short the inductors to provide more voltage to the spin motor and the torque motors. Once up to speed, inductors switched in to drop the voltage. Really pretty interesting. Well, IMHO. Oh, and mechanically, cut the power takes 20 minutes or more for the rotor to fully spin down. The bearings must be amazing. We have really forgotten how advanced magnetic control stuff was back in the day.
 
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Offline MK14

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Re: Sperry 311 / Honeywell vg-311 gyro
« Reply #2 on: February 18, 2023, 05:33:00 am »
cut the power takes 20 minutes or more for the rotor to fully spin down. The bearings must be amazing.

That is amazing!

Presumably, too much friction/drag, may affect its reading accuracy, by causing drift and other errors in the readings, as time goes on.
 

Offline Amateurtelecom

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Re: Sperry 311 / Honeywell vg-311 gyro
« Reply #3 on: June 04, 2023, 02:46:53 pm »
Would you be kind enough to contact me? I bougt a Sperry 311 gyro and I would luke to receive a copy of your service manual.  Can you help me?

Jacob from The Netherlands.
Www.polytech.nu
 

Offline Amateurtelecom

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Re: Sperry 311 / Honeywell vg-311 gyro
« Reply #4 on: June 04, 2023, 06:29:30 pm »


By the way, this is what is looks like inside. A masterpiece of precision engineering.
 
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