Discussion in 'Aircraft General Discussion' started by Phil Perry, Aug 8, 2017.
Could brexit lead to a resurgence in the British wooden aircraft industry?
The Wooden Wonder will only fly again, if they can also find a buried hoard of brand-new Merlins!
Discovery of lost WW2 Mosquito plans will allow 'Wooden Wonder' to fly again
At least, this time, any new ones built, will have the advantage of modern adhesives that don't come apart after a couple of decades in the tropics!
Quite interesting to see that the plans are preserved on microfilm. Microfilm has been recognised as one of the most enduring methods of preserving records.
The problem we will have in the future, is that our electronic-based, and constantly changing poor-quality electronic storage methods, will be useless and unretrievable in 70 years!
Even NASA is bugged by having older material stored on systems that made the information virtually unretrievable.
They were recently chuffed to find some antique computer equipment here in Oz that was taken back to the U.S. and reconditioned, so they could access that 1960's lunar exploration information.
Point Cook Museum would undoubtedly be interested in this find. They have been restoring a Mosquito quietly for years.
I would have thought that a present day Mosquito would, where appropriate, be made of composite and epoxy impregnated wood where required.
Power would be turbo prop - no question.
It may even be pressurised and have additional seating in the "bomb bay" - why not?
That wonderful silhouette and outstanding flying quality need not be saddled with old technology for the sake of misplaced authenticity - leave that to a restored original..
There is the story about Vietnam veterans who were seeking compensation for exposure to Agent Orange. They had to dig up records of where and when they had served. Retired computer experts had to be found to rebuild obsolete hardware so the old magnetic tapes could be read.
I've heard there's some in Burma ......
I kid you not, I would make Merlins (reasonable facsimiles) in a heartbeat if the right person came along and asked me, my city is setup is setup for it. I was watching some 1 meter long conrods getting nitrided just last week for example. this is large engine manufacturing heaven here.
really? surely there's quite a market for merlin copies? You could sell them like hot cakes.
I thought of the 'MERLIN' problem as soon as I read about that too. . . There is definitely not a surfeit of those around now, unless a lot of them are found intact under the mud in Myanmar along with the intact Spitfires in crates ( ? )
I'll bet that the Chinese could make some. . . Oi, Bex ? ? ? ?
EDIT : Sorry Mr. Bex, I missed your post above ! . . .
The thing is I couldn't make exact replicas, still the same spec etc, but too much time and too much cost, so for some it would be seen as a new engine, not a Merlin, so the question is, is there still a market for that?
Anyway, anyone reading this I can put you on to some good people to make castings and crankshafts, rods, etc. in my City.
My area is a bit bizzare actually, inland but we make big boat and ship engine internals, not a car engine manufacturer close, but we have some amazing crankshaft and rod makers who's stuff is seen as famous American V8 performance brands that I shouldn't mention, so maybe I should just Scat like an Eagle ...
Oh by the way, there is a Guy somewhere out there in Internet Land who has or is documenting an entire Merlin in 3D bolt for bolt, good starting point!
why not make these Merlins in England?
I can recall a story about the Merlins, when the Americans took on major production of them (the Packard-Merlins) - and the Americans were appalled that the Brits were using fractions of an inch in the blueprints (as in 11/16", 25/32", etc).
The Americans had been using decimal inch measurements in engineering for decades, so all the blueprints had to be re-written in decimal inch measurements, so the American engineers could work with them.
Then the Packard engineers asked the Brits for their engineering calculation figures for component strength. There were blank looks from the RR engineers.
"We've never done any", said the RR engineers. "We draw up the components design, and then test it in the engine. If say, a conrod breaks, we redesign it to make it stronger, right where it broke!"
The Packard engineers were even more appalled at this news, as they had always designed engines, using calculated rotary centrifugal forces, piston inertia forces, and thrust loads, to reach calculated stresses, etc., - to come up with the likes of a conrod design.
The RR engineers deemed all this engineering calculation stuff a bit airy-fairy, and reckoned it just wasted a lot of time.
Maybe they were right, because there's obviously quite a few engineering calculations in engines that are not correct, because there's plenty of engines with weak components.
The RR approach kind of reminds me of Selby Ford - the Beverley powerhouse operator from W.A., who built his own aircraft (the Silver Centenary) from scratch, without any formal plans, without any engineering calculations, and built from plans sketched on the town powerhouse floor, in chalk!
The Silver Centenary flew and performed beautifully - but Selby could never get an AWC for it, because he couldn't produce the plans and engineering calculations!
Interesting story, but I'm not sure it's all true. I was a draftsman in the 1960s working on US drawing (with the warning "not to be supplied to Cuba" and we were working in imperial, SAE. GM drawings I worked with were also in imperial. Packard was an upmarket company so may have done complex engineering calcs, but whether that produced longer engine life is a good question. Certainly, the engines on the first B29s, from memory built by Cadillac (GM) were appalling, with a percentage of aircraft returning from missions with an engine or two seized or with a rod through the side.
And it's still flying.
'AWC-less' Silver Centenary. It's of interest that this aircraft which was on unrestored static display in the little town of Beverly for many years has been restored to flying condition by, I believe, Ford's grandson and is hangared and been flown from SABC/SAA's Serpentine Airfield near Perth.
TP - When I spoke of "Decimal Inch", I was referring to the American engineering style of converting fractions to thousands of an inch. Thus 1-9/16" on RR plans became 1.562" on Packard plans.
SAE standards were not used on the Packard-Merlin. Packard and RR engineers had an excellent working relationship and the overall plan was to minimise design changes between RR Merlins and Packard-Merlins, to ensure as much interchangeability as possible.
Packard used BA, BSF and BSW threads in the construction of the Packard-Merlins to ensure interchangeability.
However, there were no suppliers of fasteners with these threads in the U.S., so Packard made its own tooling for the British fasteners, and produced all the BA, BSF and BSW fasteners needed for the Packard-Merlin production.
There were other huge problems with the Rolls-Royce plans. RR drawings were in 1st angle of projection, compared to the Packard drawings which were in 3rd angle of projection. This can be put down to the lack of international standards.
First Angle Orthographic Projection
Essentially, RR Merlins were handbuilt, with parts finished by hand - the Packard-Merlins were built on mass production lines, with accurate repeatability standards for all components.
Rolls-Royce utilised an apprenticeship system which trained the personnel to become skilled craftsmen - with the right, when they graduated, to stamp their initials in engines they built, to show the engine was "built by Joe Bloggs".
The tightness of any RR fastener was measured by the RR craftsmans "feel".
Packards mass production lines didn't allow this, and Packard listed every nut and bolt on the drawings with a specified, measured torque.
Roll-Royce maintained parts interchangeability between the different marks of engine which necessitated the use of adapters.
When Packard redesigned the engine, they adapted it for the use of American accessories and thereby stopped full interchangeability.
Materials used in the RR engines were also to a non-international standard.
Packard had a hard time duplicating the nitriding process for the RR crankshaft, with the nitrided, molybdenum chrome steel crankshaft, superior to anything the Americans had. Hispano originally came up with the nitriding idea, and held the patent on it for many years.
Interestingly, amongst the Merlin air-racers, the Packard crankshaft is regarded as superior to the RR crankshaft.
On the other hand, Packard improved some of the Merlin aluminium castings, by developing an improved aluminium alloy.
The whole Packard-Merlin story probably warrants an entire book in itself.
A well known Australian racing engine maker has dismissed using "castings" as they had too many faults.
Now he uses a billet of alloy in the "cnc" machine.
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