Instrument ID

[Herod]

Can anyone shed light on which aircraft this would have been fitted to? Presumably British. Thanks for any clues.

https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/640x960/machmeter_2_365555736cf46741bb0d86cbaeef0fa3b145ef7d.jpg
https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/960x640/machmeter_1_9aa9fb09df8f49e63d6ad01a555f6bbb7f4b9247.jpg

[DaveReidUK]

I'd guess that it's from a Lightning simulator (it's not a genuine Machmeter from an actual aircraft).

[dook]

I flew several marks of the Lightning and it's not from that aeroplane.

Indeed, the F3 onwards had the OR946 instrumentation which included a combined speed strip indicator.

[DaveReidUK]

OK - probably not from a Hastings, either. :O

[DaveReidUK]

Joking aside, it appears that the F.2/F.2A had a clockwork Machmeter.

I don't know how representative this project to rebuild XN728's cockpit is:

https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/347x627/f_2a_machmeter_0086be53215eaaf61da53ac58090fdd3af18f640.jpg

but the M2.2 range matches, and Redifon definitely made a Lightning simulator (FAST at Farnborough at currently rebuilding one, in fact).

https://twitter.com/xn728a1/status/725066215824216064

[dook]

The F2/F2A is very close to the F1A. The F2a I haven't flown.

I think this instrument might be from a British experimental aeroplane and wonder if the two images are not connected.

The fastest Lightning of them all was the F3 but flying one I only ever achieved M1.9 off a tanker and full to the brim.

[DaveReidUK]

I think this instrument might be from a British experimental aeroplane and wonder if the two images are not connected.

I'm not sure which two images you're referring to - the two in the original post are clearly the same unit.

As it's definitely from a sim it's more likely to be one for a production type rather than an experimental aircraft. Could be an F-4 sim rather than a Lightning one, I suppose.

Either way, the single, electrical connector on the back is a giveaway that it's not displaying genuine M:


https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/370x408/simulator_machmeter_rear_view_d81698652ecbd3ae51b1946d9b192c 8fd4ce7964.jpg

[Bagheera S]

The key piece of information in the photo is the serial number ends in /63 indicating that the instrument was delivered in 1963. So the system it meant for would’ve been spec in a 55-60 time frame but ongoing in 63. That’s too early for F4 and Concorde. So it’s Lightning, or Type 188, or TSR2, or maybe a research project. The Bristol Type 188 had a strip indicator, was intended to have a max speed of Mach 2.8 (best speed achievement was 1.8 due to intake problems) and the project was near the end in 63. TSR2 had a maximum speed of Mach 2.25, in 63 reduced to Mach 1.75 by issue 2 of OR.343. Lightening was Mach 2.2 and 63 the project would have been in a significant component delivery phase, so it tops my list of suspects. A un-named research project, possible but unlikely.

[DaveReidUK]

The key piece of information in the photo is the serial number ends in /63 indicating that the instrument was delivered in 1963. So the system it meant for would’ve been spec in a 55-60 time frame but ongoing in 63. That’s too early for F4 and Concorde. So it’s Lightning, or Type 188, or TSR2, or maybe a research project. The Bristol Type 188 had a strip indicator, was intended to have a max speed of Mach 2.8 (best speed achievement was 1.8 due to intake problems) and the project was near the end in 63. TSR2 had a maximum speed of Mach 2.25, in 63 reduced to Mach 1.75 by issue 2 of OR.343. Lightening was Mach 2.2 and 63 the project would have been in a significant component delivery phase, so it tops my list of suspects. A un-named research project, possible but unlikely.

The serial number in the OP's photo actually ends in /68, hence my suggestion that the sim could possibly be an F-4.

[wiggy]

As I recall it the F-4M/K didn't have a stand alone Machmeter, it had a combined ASI/Machmeter (certainly in the front seat...).

If by some chance it is it's UK F-4 related then I'd guess it was whatever was fitted at the instructors station in the sim or as fitted on the Air Intercept Trainers...

[dook]

The instrument in the illustration shows a white line limit of M1.7.

This is commensurate with the limitation of Lightning Marks F1, F1A F2 due to directional stability and radome strength considerations.

Subsequent marks with the larger square topped fin and strengthened radar housing were cleared to M2.0 ( not M2.2 as previously claimed).

It could thus indeed be from a Lightning simulator. I have flown the F1A simulator, and it is a tribute to my grey matter that I can't remember details.

[DaveReidUK]

The instrument in the illustration shows a white line limit of M1.7.

This is commensurate with the limitation of Lightning Marks F1, F1A F2 due to directional stability and radome strength considerations.

If you're referring to the photos in post #5, they are from the rebuild of F.2A XN728's cockpit, hence the limit line.

Here's an original in situ:

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/464x330/lightning_machmeter_ccea2e8abbdf25c4a4af3364ce49276c5230b3c4 .jpg

But we're still left with the mystery of the OP's photo.

[India Four Two]

Can someone explain the expanded scale between 1.0 and 1.1?

A rent in the space-time continuum perhaps? :)

[newt]

Time to accelerate!l

[DaveReidUK]

Can someone explain the expanded scale between 1.0 and 1.1?

I assume that 50+ years ago, the Lightning's Machmeter was a purely mechanical instrument, unlike nowadays where there's an Air Data Computer in the loop doing clevr stuff.

Subsonic and Supersonic Flow through Pitot Tubes (http://lancaster.ac.uk/~rennien/BScProject.pdf)

[dook]

India,

Isentropic or non-isentropic calibration ?