Hi Martin, no idea what it is used for, but RAF Marham on the box reminds me when a workmate and myself did some work inside one of their workshops, and from what I remember, it was modifying/repairing some security caged areas. They had some pretty and expensive Aircraft parts to to store in the place. Bit of a faff signing in and out of the camp though.

Regards Nick.

A better view, or typed out version, of the NSN might assist.
I’m assuming it’s the NATO Stock Number.
There’s a few sites around which have search engines.
e.g. https://www.milspares.co.uk/products-services/nato-codified-commodities
or https://www.iso-group.com/Public/Search_Results.aspx?ss=01t-c-20900
I also have an ex RAF friend looking at this one.

Bill

Probably totally wrong, I’ve no specialist knowledge.

However it seems to be measuring very small deviations (dial is in mm) of something (with appropriate calibration required).

A search online turned up a page
https://dolphmicrowave.com/default/why-use-flexible-waveguides-in-radar-systems/
which mentions physical distortions in radar (RAD) systems cause by electro-magnetic pulse radiation(PULSE) from nuclear weapons.

Against that it doesn’t look like electronics, the heavy construction and the Rolls-Royce symbol (on the box of an identical tool currently on ebay) are suggestive of measuring changes inside an engine.

The Label on the ebay box for a similar unit suggests that it’s engine rather than radar.
Turbo-union was a consortium which made the RB199 engine for the Tornado aircraft.

A search on RB199 pulse probe turned up this on ebay.

Described as a Tornado RB199 LP Pulse Probe.

Looks similar in shape and length, maybe the kit was to aid in fitting this to the appropriate clearances in the engine.

🙁

So many references … So many dead-ends

MichaelG.

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I have followed this with interest having recognised some of the part number.

O1T was reserved for the RB199. Given the date it was probably first used on the Mk103. NL refers to the low pressure compressor speed. The pulse probe measured it as a phonic wheel, detecting capacitance between it and teeth on a gear wheel in the low pressure gear box. This is not rocket science, my Myford lathe uses such a system to measure speed. The low pressure compressor parts were made by FIAT. The item in the box is the probe holder. The probe would be in another wooden box with a different number. This would have only been used during engine test on a bed, not in flight.

I don’t think I have broken the Act.

JA

I agree, clearly a device for setting the clearance for a probe in a RB199 Tornado engine. The probes are typically magnetic sensing rather than capacitance. They can sense any variation in magnetic field caused by a moving metallic part. This could be blade tips but is more likely to be a gear or coupling.

On 9 August 2025 at 17:39 SillyOldDuffer Said:

On 9 August 2025 at 11:50 Nicholas Farr Said:

… Bit of a faff signing in and out of the camp though.

Regards Nick.

Many strange experiences visiting MoD sites, forgivable because they had to be serious about security due to active terrorism and intrusive Foreign Intelligence Services!

My favourite occurred at Devonport Dockyard, where at 8am a packed waiting room and queue out the door was being processed by a portly and aged policeman.   He was unbelievably slow, apparently half asleep.  No one complained, perhaps because he was armed with a pistol.

After about 40 minutes, there was an audible sigh of relief when a sergeant appeared.  Until he said, in a strong Plymouth accent, ‘ere je-arge, would you like a cuppa tea?’   On the affirmative, he disappeared.  No tea turned up in the 30 minutes it took me to get my pass!   Perhaps a behind the scenes crisis, and the chap on duty was exhausted after a double shift, with no prospect of help.  Or was it typical?  I shall never know!

Dave

 

Hi Dave, yes I understood that security was a critical factor, and we had to understand certain codes and what action was needed if any, one of the codes I still remember was UFO, no , that didn’t mean unidentified flying objects, it meant unidentified foreign objects, that’s to say things that really looked out of place, which might be a threat of some kind. Luckily we didn’t see anything of the sort.

Regards Nick.

MOD site security is intersting.
I don’t think I’m giving anything away by relating this 28 year old story. I was part of the team that designed, built and ran Thrust SSC the fastest car in the world, first and only to go supersonic.
Apart from the space frame and some panels the car was built at Farnborough. This was actually on the airfield secure site.  Like many sites, even commercial ones, there were random searches when you left the site. I was stopped one day and the asked to look in the boot of the car. I wan’t worried until I looked and relaised thet it contained:
Six explosive squibs (used to activate the brake parchutes).
A dynamo exploder unit.
A couple of lead acid batteries.
A couple of reels of cable.
A box containg some gyroscope spares including mercury tilt switches.
A can of Fuel
The only thing missing was a bag of fertiliser!
And a HF radio from a Phantom aircraft at Boscome Down.

The guy asked “is that all your own stuff?” I said yes and he waved me on…

Too keep it on topic, Thrust SSC used the same type of magnetic probe (variable reluctance probe) to measure the wheel speed. The brakes were carbon fibre disks that floated on a steel hub. Torque was transferred via dogs that engaged slots in the cargon disk. The reluctance probe detected the passing dogs. Counterintuitively the cockpit Machmeter was driven by this signal via the onboard computer. The “speedometer” on the other hand was a pitot-static (pneumatic) instrument. In fact the speedometer was a Machmeter that I had concerted into a high range airspeed indicator.
The wheel speed signal was also integrated and used to drive a “distance to run”countdown display in the cockpit. Andy (the driver) could preset this at the start of the run. While the display was digital (a voltmeter module) all the processing was analog. The display (reading 11.0) below the speedometer  can be seen in the attached image. The preset control is on the far right below the clock.

Robert.