Help Sought to Identify Gyrosyn Nav Components (1 Viewer)

[Crimea_River]

I am looking for someone with knowledge of vintage Sperry Gyrosyn navigation equipment that would have been installed in the Spartan Air Services late model Mosquito aircraft in the late 1950's. I am on a team restoring such an aircraft ( Mosquito RS700 Restoration) and we are trying to fit out our aircraft with authentic period equipment from the time that it operated in the late 1950s.

I have a list of components that I was able to grab from Spartan Equipment Lists that were submitted with Weight and Balance reports in 1958. These components, written exactly as they are described in the Spartan documents, are as follows:

- Gyrosyn flux valve & compensator Sperry 656520 (weight 1.3 lbs)- we have the flux valve unit which was found in one of our aircraft's wingtips. Not sure if the compensator is part of that unit.
- Gyrosyn amplifier A-2/C (weight 6.7 lbs)- we do not have this unit but have seen one locally.
- Indicator Sperry V7A/C (weight 1 lbs) - we have this unit
- Inverter & Mount for Gyrosyn Compass (Bendix) (weight 7 lbs) - we do not have this unit, nor is there a model number given
- Gyrosyn Repeater Indicator Sperry C4 (weight 1 lbs) - We do not have this unit. The C4 unit replaced an earlier C2 unit that was installed
- Gyrosyn Control Unit (Sperry) (weight 6.7 lbs) - we do not have this unit and no model number is given
- Gyrosyn Controller Sperry J2 (weight 0.8 lbs) - we do not have this unit. This item is listed separately from the one above

Spartan appears to have used the Gyrosyn system in addition to a conventional ADF system comprised of an HF Receiver and Loop antenna which are better-defined and sourced. The help I am looking for is this:

1. Does the above list make for a complete list of components for the Gyrosyn nav system, apart form accessories like mounts and antennas? (Spartan did not use an autopilot system so no need to address that)
2. Given that some of the descriptions appear to be generic, can the individual items be identified better so that we can source the specific equipment needed?
3. How are these individual components connected together? Photos and manual references would be ideal.

As you might be able to tell, I am far from knowledgeable in this field and so any help would be appreciated. Our ultimate goal is to procure authentic but non-working examples of the components that would have been carried in our airplane in the late 1950s and to mount and connect them as they would have appeared at that time.

 

[MiTasol]

The compensator is a small unit that may or may not have been built in to the flux valve depending on the make and model. AFAIK most were built in and appear as a square block on the base of the unit. Some had N-S on two faces and E-W on the other two.

If you can post a few side view photos of the valve showing the bottom I should be able to identify if the compensator is fitted.

Most gyrosyn compasses I have worked on did not have more than one indicator so had only three components - indicator, flux valve and inverter (and that only weighed grams - not pounds). I would suggest you look at wiring diagrams of the period for RAAF Lancs and North Stars and similar and see what shows up in them for systems with multiple indicators.

The gyrosyn was a compass system for use on aircraft where metal or electrical equipment in the cockpit could cause significant compass errors. Spartan probably used it because it was more responsive than magnetic compasses that tend to lag in comparison.

 

[Crimea_River]

Very much appreciate the input thanks. I can take a pic of the flux valve on Saturday and post it.

A bit surprised about your comment that the inverters are "grams- not pounds". The reported weight of the gyrosyn inverter, straight from the W&B report, is 7 pounds. Two other inverters we have for the ADF system are 21 pounds each.

 

[MiTasol]

Attached is some wartime info on the complete system as it existed then. The inverter then weighed 2 pounds but later units used a peanut inverter which weighed way under a pound.

 

[Crimea_River]

Thanks again for the added info. No mention there of an amplifier, nor the controllers.

I found a page excerpt on Air Corps Library which helps a bit. This time, we see an amplifier, but again, no controllers are identified. I guess I could pay 90 bucks and get the full manual but that's a bit steep and a crap shoot for content unless I know it has the information I need.

I have found the A-2/C Amplifier at a local museum and it looks like this:

The primary indicator used by Spartan is the Sperry V-7A which looks like this:

The repeater indicator, located in the nose position, started out as a C2 and resembles the unit you included in the excerpt above.

I gotta go by what the W&B Reports tell me and the inverter and mount are definitely reported as 7 pounds vs the smaller number you quoted. Maybe Spartan used a different unit that they had on hand that provided the needed function. Note that they say it's a Bendix unit. I did a location drawing a couple of months back showing the location of the reported Gyrosyn components relative to the aircraft datum. I believe that all items but the flux valve are within the fuselage.

 

[MiTasol]

There is a C-45 Expeditor site that has a lot of RCAF manuals on such items and the RCAF used the Expeditor as a nav trainer about that time so I would first see what that site has.

I cannot remember the name but time is part of the name I think.

I typed time into my browser and guess what showed up? Time Travel Air Go to Technical Library, Mil pubs - quick glance shows these

 

[Crimea_River]

Awesome, thanks. Lots there to look through.

 

[Crimea_River]

Here's the Flux Valve that came with our airplane. The Compensator is integral with the valve as can be seen.