I was helping my parents clear out in prep for moving to retirement village. My father being a British migrant electronics nut who had done Nasho in the RAF (Boscombe Down) happened to have some old dials.

One caught my eye and is now in my possession: a rev counter from a Handley Page Victor bomber from the late 1940s ... retired in 1993 (now that's longevity).

It's a cool looking old dial. It has single positive and negative screw inputs on the rear. 

Can I use them on my K100 bitsa bike? Am thinking of using a thick flat piece of aluminium sheet for speedo and revs.

My father was saying that they are very sensitive and that I would probably blow it with too much input. 

Q: what is the input value / voltage for the rev counter?

Q2: What wires must be attached for the bike to start? I previous tried to start the bike without the speedo etc attached... now go... but obviously not everything is needed.

Thanks for any help 

Guy

If the cluster is off then you can start the bike if you pull the clutch in. (Provided the clutch switch is working.)

Starting without any knowledge of the likely input of the gauge, I'd look to use a signal generator to carefully try it first. Maybe the gauge is analogue (responds to a variable voltage - not a pulse) who knows?

It'll be possible to build a circuit to take the K100 input and produce a signal that drives your gauge, but I think you've got yourself a bit of a 'project' there!

My ex-RAF aircraft engineer friend (1952-1966) thinks the Victor strategic jet bomber, first flight December 1952, had a 115V AC electrical generation system. Obviously, with that base you can easily get anything from ~150V DC downwards and 115V AC downwards, and only slightly more effort to go upwards. 
Just a + and - terminal suggests a DC power source with enough grunt to drive the gauge innards with a superimposed wave or pulse to give a ‘data’ input to generate a proportional gauge response. Alternatively, a pulsing DC, also with enough grunt to drive the gauge. 
Typically, it doesn’t take much current to drive a gauge, but the internal impedance can be set so that whatever input voltage you want can be accommodated. 
That’s a surmise rather than a statement with authority. 

Hope someone can go further. 

Bill

I'm going to guess that the signal level is going to be on the millivolt level.  You could try connecting to the headphone output of your computer and get a signal from an audio generator.  Start with the signal at minimum and bring it up slowly. 

Being a one-of-a kind, I would spend a lot of time on the web finding out as much as possible about antique avionics before I put any power to it.

Just a thought - I didn't think aeroplane engines revved that high?

If it's off the APU then it could be hitting as high as 20,000RPM. Piccies, Guy?

Did a tiny (and I mean tiny) bit of research about aircraft RPM gauges. Electrical gauges used a motor-generator principle whereby an electrical motor attached to the engine and driven by the crankshaft, generated an AC wave that was transferred to the gauge. The gauge had a motor inside that responded to the AC drive signal.

This is somewhat the same principle used by the BMW. You'll have to verify this information as being correct for your bomber gauge.

Schematics for the BMW OEM circuits

Sounds like they used synchronous motors to replace the cable in an eddy current speedometer.  This would make sense in an airplane as the routing from the sender to cockpit panel would be easier and more reliable with wire than with a rotating cable.

GF Wollongong wrote:I was helping my parents clear out in prep for moving to retirement village. My father being a British migrant electronics nut who had done Nasho in the RAF (Boscombe Down) happened to have some old dials.

One caught my eye and is now in my possession: a rev counter from a Handley Page Victor bomber from the late 1940s ... retired in 1993 (now that's longevity).

It's a cool looking old dial. It has single positive and negative screw inputs on the rear. 

Can I use them on my K100 bitsa bike? Am thinking of using a thick flat piece of aluminium sheet for speedo and revs.

My father was saying that they are very sensitive and that I would probably blow it with too much input. 

Q: what is the input value / voltage for the rev counter?

Q2: What wires must be attached for the bike to start? I previous tried to start the bike without the speedo etc attached... now go... but obviously not everything is needed.

Thanks for any help 

Guy

Hi Guy,
Try contacting the HARS at Albion Park - they may have some information on typical voltage levels to drive the tachometer.

The Victor was a jet engine plane - what does the tachometer redline at?

Richard.

robmack wrote:Did a tiny (and I mean tiny) bit of research about aircraft RPM gauges.  Electrical gauges used a motor-generator principle whereby an electrical motor attached to the engine and driven by the crankshaft, generated an AC wave that was transferred to the gauge.  The gauge had a motor inside that responded to the AC drive signal.

It's called 'autosyn' and was originally developed by the Pioneer Instrument Company. Depending on the usage and manufacturer autosyn voltages seem to have varied between 26 vac and 115 vac. One of my current RL jobs involves simulating an aircraft fitted with a panel full of autosyn gauges running at 26vac with a 400Hz sine wave imposed on it as the signal carrier.

Not being an E & I guy and only having limited aircraft avionics knowledge, I would suggest that the +ve and -ve terminals are for the instrument lighting.  There would likely have been a little shroud above the instrument with either red/white light and the instrument would have back lighting as well.  

Not being all that familiar with the UK aircraft standards but if it was NATO/north American then would have been 28VDC.  And yes as Bill suggests then 115VAC is the AC component.  From memory the last aircraft type I was involved with was 28VDC for just about everything and a handful of avionics requiring 115VAC, usually various radio or nav items.  

The battery bus (28VDC) had a few essentials powered of it including cockpit lighting and allowing enough for an engine start which bought the generator online. In some ways similar to our K bikes.  I was always worried about overheating the battery and causing thermal runaway.  

The Valiant, Victor and Vulcan were the backbone of the RAF V Bomber force against those nasty Russkies back in the day with the Victor being the last serving after conversion to tankers, retiring in the early nineties.

Pictures would be nice. We could probably give you a definitive answer then.