[time-nuts] OT - DC-10 gyros

Peter Gottlieb nerd at verizon.net
Wed Mar 27 18:47:08 EDT 2013

Yeah I'd join a gyro-nuts group.  I have a shelf full of weird gyros, a stable 
platform, other gyro stuff.  I made a little power supply to make 28 volts 3 
phase 400 Hz, found it in an app note, for running a set of three tiny rate 
gyros I picked up.  I'll go dig it out and let you know.


On 3/27/2013 4:40 PM, Bill Ezell wrote:
> Well, I can come up with something topical, read on. :)
> I saw a 'Bendix yaw-rate gyro' on FleaBay recently for $14.50. Of course, I 
> had to buy it.
> What I got was the yaw-rate gyro package from a Northwest Airlines DC-10 that 
> was stripped for parts around 2000. The gyro included the pull tag with tail 
> number, the license number of the A&P mechanic that pulled it, and some other 
> cool stuff.
> What it turned out to really be is two gyros with two sets of electronics in 
> one box about 6" x 2" x 5" box, all vintage '80s or so. Even better, it's a 
> strapdown system. The actual gyro wheel is about the size of your thumbnail. 
> I've just started tracing things out, and I've gotten the gyros to spin up. I 
> really love mechanical gyros for some reason, too bad there's not a gyro-nuts 
> group. I'm going to have great fun getting the package traced out and running.
> So, to be a bit more topical, the package of course needs 28V 400Hz for the 
> gyros, 28VDC for something, and +/-15V for most of the electronics.
> Question - anyone figured out some clever solution for the 400Hz power? I 
> faked it with a signal generator and power amp, but that's a bit bulky. I'm 
> thinking I'll use one of the class-D amp ICs and a simple op-amp phase-shift 
> sine generator.
> Topical in a more abstract way, strapdown systems really are very interesting. 
> They require precise integration of the rate output over time to derive 
> velocity and position, and really weren't practical until the 70's when small 
> enough computers existed to do the requisite calculations.  (I worked on the 
> nav system for the Trident missile back in my Draper Labs days).

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