[time-nuts] OT - DC-10 gyros

[J. Forster]

An appropriate (but small) Group already exists:

http://tech.groups.yahoo.com/group/Aerospace_Hardware_Collectors_Group/

-John

=======================

> 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.
>
> Peter
>
> 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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