£1000 to make a Spitfire aircraft fuel tank gauge. Can it be done cheaper?

All the comments about reliability of air-safety-critical parts and assemblies are valid, but that doesn't stop designers heading off on goose-chases when confronted with a requirement for old aircraft parts.

I was working for an aircraft component company when the Nimrod project was delayed and the Shackletons had to serve for another couple of years. We were trying to quote for a depth-charge dropping sequencer, originally made for Wellington bombers - the GA had been going through approval while the Bismarck was loose in the Atlantic, and it was one of the only 2 *actual blueprints* I've ever seen. A bloke I knew in the DO had a detail drawing of one of the contact pads in front of him and was laboriously going through specs for various materials, trying to decide which was closest to the original.

All it said in the material box on the drawing was BRASS...

As a matter of interest, are there any old timer pilots here who would be able to comment on the reliability of original spec gauges?

I worry that all of this checking and materials testing will only produce a gauge that was inaccurate and/or unreliable in the first place!

I have been involved in work on a few historic aircraft but one of the most bizarre was a military aircraft namely the Canberra.

The company I worked for did a lot of work on service aircraft and we were asked to make a new throttle box for one of the PR Canberra's that were then in service. Most of the work was quite straightforward, until, that is, the provision of the rubber covering for the throttle levers.

These had been made by Raleigh in Nottingham and were the handlebar covers for a children's bicycle made in 1946 or thereabouts. Needless to say, they didn't have any spares!

I'm not sure how we worked around that one, probably by 'phoning every bike shop and restorer until we found some that were useable.

Brian

#andhow much do you think a modern fuel gauge costs? How about $250 for a non approved one?
https://www.aircraftspruce.com/pages/in/fuelinstrumentation_fuelgauges/belite10-06068.php
You would be lucky to get any approved (TSO'ed or OEM) gauge for £1000.
I've desigined and built fuel gauging systems for three aircraft, one turbo-prop, one jet and an airship. These did not use any "aircraft grade" materials. The turboprop was the NAC Fieldmaster https://en.wikipedia.org/wiki/NAC_Fieldmaster. This was a resistive system with Lucas commercial vehicle float type transmitters, electronics box and a commercial Anders 270 deg meter with custom scale. As a design authority you can use anything that meets the requirements, it does not have to be "aerospace grade". Biggest problem I had with that system was convincing Desmond Norman thatt a diecast aluminium box was OK. The was used to diecast meaning Mazac or pot metal. The electroics boxes a aluminium alloy. I know of another certified aircraft that used a Sodastream CO2 cylinder for the emergency undercarriage power source.
Last custom fuel gauge I specified cost 5 figures. That was just the gauge, not the tank probes or electronics box.

Robert G8RPI.

Just watching this evenings episode and thy are lifting a fuselage with a ratchet type cargo tiedown hooking the end hooks together. While probably strong enough it's certainly not approved and tested lifting gear! Just to top it off they then had two guys worlking under the suspended fuselage. At £2M for a re-build you would think they could afford a proper sling / strop. Then they were fitting the wing with pictures of "fettling" a rear attchment bolt hole with a file and then driving the main spar bolt in with a hammer. Contrast recent Guy Martin Spitfire build TV program where the same bolt was precision ground to original tolerance (0.0005" IIRC) and then having to let it sit on the bench for a while because the heating from Guy holding it in has hand caused enough expansion to stop it going in the fitting.
I'm not impressed by The Spitfire Company.

Robert G8RPI.

I wonder if we are not retrospectively applying standards that were not in existence back then? I have very little knowledge of aviation or of military aviation of the period but I suspect when things broke the priority was to effect some kind of fix and get them back in the air as quickly as possible. There was an interview on the David Jason documentary with a ground crew member from the period and his accounts of slapping a bit of canvas over the bullet holes did not include a full airworthiness inspection! In fact I doubt many of the planes of the era ever got to a scheduled major overhaul before they were downed! I will ask my uncle next time I see him - he was the pilot (George) featured in the Spitfire Factory that flew that particular aircraft and I don't think any of the others he flew are still around. He flew Mosquitos on reconisance, Halifaxs on bombing raids and repositioning Spitfires, I don't think he flew the latter in battle.

Paul.

No, we are not.
The restorers are not working under wartime production pressures or doing battle damage repairs.
There is no excuse for not using proper lifting equipment, even worse when you are being filmed.
Even the wing bolt tolerence from the Guy Martin program came from the original drawings. Incorrectlty made or installed wing attachmens can and have caused fatal accidents. More than one Tiger Moth (wrong maerial or improperly made threads in lowwer wing tie) and a Chipmunk (undersize spar bolt) as well as the Reno Mustang (worn out fibre locknut) comme to mind. On the other hand "lapping a bit of canvas on a hole" was and is the accepted way of repairing damage on fabric covered aircraft. Assuming the "canvas" is the correct fabric (linen in WWII) and a bit of are is taken that is.
I have worked on several "warbirds" over the years including Spitfires.

Robert G8RPI.

That reminds me of the HP 115 , a one off slender delta research aircraft that was part of the Concord development . A last minute panic for a brake lever produced a Ford Popular hand brake from the dealer in Radlett.

The fuel guage on my Father's home built Turbulent was 2 ping pong balls and some welding rod.

Aircraft grade aluminium ? Not much different from 6082 T6 architectural grade that's easily available , it's the availability of thin guage sheet and tube that drives towards aircraft spec........... And then theres the paperwork to prove that it realy is what it says on the tin £££

Always difficult to get at the truth in complex situations, and WW2 was as complicated as it gets. Doesn't help that the subject is overlaid with propaganda, where both sides fibbed about losses for good and bad reasons. The Luftwaffe was exceptionally dishonest and made the mistake of lying to itself, which caused severe problems as the war progressed.

History tends to concentrate on pilot and aircraft performance, which is misleading. TV always over-simplifies, and a good example I watched last year featured a Battle of Britain Spitfire vs Messerschmidt comparison, in which the German plane was declared winner because it had a 20mm cannon.

True enough, but the programme ignored the fact that the Me109 has a narrow undercarriage and was often damaged landing on the bumpy grass airfields the time, usually injuring the pilot. Accidental damage is as important as battle damage, and the Me109 was accident prone.

The programme ignored many other important factors. The complexity of German aircraft design made it necessary to centralise the Luftwaffe's Ground Repair Organisation. Only simple repairs could be done at the airfield, otherwise the plane was sent to a repair depot, probably by train. It took ages. German airfields became littered with unserviceable aircraft, many of them with relatively minor faults, which reduced training time as well as combat availability.

The Me109 suffered other disadvantages during the Battle of Britain: it flew into a efficient air defence system featuring radar plus sophisticated command and control; the plane only had fuel for about 20 minutes over South East England, and if shot down over England Germany lost the expensively trained pilot as well as the aircraft.

Bottom line is the Luftwaffe failed to overcome UK defences because they couldn't match RAF availability. Systems and logistics were more important than small technical details. All that mattered was the 1940 Spitfire being good enough to take on an Me109 despite the cannon, and there were more Spitfires available than Me109s.

Everyone in WW2 put considerable effort into keeping planes airworthy. Aircrew, especially fighter pilots, are enormously costly to train and take a long time to become effective. Yes people were sometimes flung into the air in poorly serviced equipment, but it meant something was badly wrong - some deeper failure of the fighting machine had forced them into action, and it usually ended badly. Perhaps the best example were the Kamikaze. When Japan's position became utterly desperate obsolete aircraft were stripped all but the bare essentials to save weight, no navigational or safety equipment, unarmed, simplified controls, including no fuel gauge, and packed with explosives to make a giant bomb. A minimally-trained pilot flew his death trap on a suicide mission. But even 100% disposable Kamikaze planes weren't flung together carelessly; the ground crew worked hard to make sure they would fly reliably to the target.

Dave

There are always revisionists wanting to change opinions about history for all kinds of reasons, some of them even honest.

It does appear, though, unless some records have been supressed and others fabricated, that RAF pilots never asked Dowding for a squadron of Me109s, whereas in the Luftwaffe...

Interesting to see what’s still available ‘used’ and ‘old stock’

**LINK**

http://spitfirespares.co.uk/Instruments%20fuel%20gauges%208.html

MichaelG.

Regarding radar, actually the Germans had very effective centimetre-wavelength radar at the start of the war while we had only the 6-metre wavelength CH system using a string of giant towers that weren't very directional. I believe it is true that the Germans flew snooping missions before the war to listen to the CH transmissions and concluded that they couldn't be radar because the frequency was much too low. But the German radars in France were operated by the army, and they insisted that all the warnings were funnelled up the chain of command to Berlin then handed over to the Luftwaffe and filtered back down again, by which time it was too late. After a similar proposal in the UK was floated and given short shrift by Churchill, the people manning the CH scanners spoke directly to the ops room dispatching the fighters, so our system beat the Germans' despite the lower quality radar.

Later on it was a different story. The Germans had to use klystrons to generate microwaves which were large and inefficient, once we had the magnetron H2S system we could put in Mosquitos and have a PPI display, like a modern radar. Apparently a Mosquito was eventually shot down and the magnetron cavity block survived - the German scientist who inspected it said "we knew they were ahead, but at least we thought we were playing the same game...". Excellent book called "Instruments of Darkness" about all this, highly recommended.

Different story at sea too. Cunningham had pushed for good radar outfits for the navy, so by the time of the Bismarck sortie in 1941 quite a few British warships had radar that could find and shadow enemies around and beyond heavy gun range. When Bismarck tried a salvo at the shadowers, the gunfire put her own forward radar out of action.

The Germans never caught up. By the time of Scharnhorst's fatal sortie at an Arctic convoy in 1943, their Admiral Bey didn't even turn his radar on for fear of counter-detection, and a hit from the RN cruiser screen soon took away that capability anyway.

Hmm,
Most of the gauges on that website are luminised with Radium. This makes them a hazard and liability. They re very expensive to dispose of properly. While the amount of radiation won't make you drop dead it is a hazard. The law is complex on these items but if you are a business you can't repair them (or even open them) without a licence. You can't legallly post them either. best left well alone.

Robert G8RPI.

It's true. Chain Home radar was so primitive the Germans decided the signals couldn't be a detection system. Apart grom the transmit frequency being ridiculously low, the pulses were triggered by 50Hz off the mains, which is exceptionally low tech. But it worked well enough.

A more advanced British radar had been captured from the Army at Dunkirk but Germany's scientists failed to realise it was only a prototype lash-up. Compared with beautifully made German equipment, it was a heap of poo, so it was assumed British radar was years behind, no threat at all. Seriously misleading! Never underestimate the other guy...

Dave