Original DH Mosquito plans found ( in large numbers )

[bexrbetter]

specifications for rolls Royce meteor engine27 litre v12

 

5.400"bore ,6.00" stroke

Ha, you wouldn't believe it, the Caterpillar 3314 V12 diesel engine is the same and all parts are made in China, so we crank, rods and pistons, we're damn halfway there already!

 

 

[Phil Perry]

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.

Darned Interesting stuff Mr. onetrack Sir !

 

Fascinating stuff. I was going to construct an article on the RR Merlin engine for one of the blogs I frequent, but you've gorn and spoiled this idea by writing it for me with FAR more interesting side issue and Packard parallel references that I'm sure, I would have dug up. . . . I present you with TWO 'Winner' accolades with alacrity.

 

The tightness of any RR fastener was measured by the RR craftsmans "feel".

 

My friend Mike O'Grady ( The ultimate Diesel specialst ) was working on a Rolls Royce ( Car ) cylinder head replacement. He couldn't find the torque figures for the head bolts anywhere, so he phoned the factory ( I'm talking 40 years ago btw ) the engineer told him to "Use a five inch tommy bar in your wrench, and apply ADEQUATE PRESSURE' on the bar to facilitate tightening of the bolt. . . . . Craftsman's feel ? ?

 

 

[Phil Perry]

A billet is cut or extruded from a casting and is prone to all the flaws of how it was cast, what material, and who cast it just the same as if it was the part that was cast.A billet part is usually superior due to the developer ordering a better quality aluminium, it's what you do if you are going to all that trouble, in comparison to a manufacturer who is going for the cheapest option possible.

 

Great writeup, thanks OT.

This 'Faulty aluminium' problem was Alleged to have been responsible for the recall of a number of Evektor Eurostar aircraft ( Made in the Czech Republic ) following the failure of of a wing mount casting on one aircraft, causing a fatal crash. . . I didn't read the final detailed reports regarding the outcome of this, ( If there ever WAS one ! ) other than the fact that the factory had changed it's foundry source for these vitally critical castings. . . Billets. . .Castings. . .all can be compromised by poor / shoddy metal formula composition / furnace control / insufficient / poorly applied Quality Control / Destructive testing methods in manufacturing procedures. . . +5G / -2G loading specs are meaningless if the component parts are not up to spec.In order to achieve this claim. . . ( Arbitrary - not TRUE loadings for that particular Flying appliance BTW - but you Know wharrimean. . . a Chain only being as strong as it's weakest link and all that. . .)

 

Epilogue.

 

Castings on the recalled aircraft were replaced free of charge, BUT disassembly / reassembly of the airframes was not. Nor was the loss of revenue incurred where these machines were used by training organizations either. . .

 

As a complete aside ( Whilst I am on the subject of the Evektor Eurostar aircraft,) there appears to be a design / manufacturing fault with the FOUR stub exhaust assemblies, which have a flexible metal hose welded to stainless steel fittings at each end. . .These things have been failing after very short periods, particularly the exhaust unit located at the rear left side of the Rotax 912 80HP engine. These have been failing at under 40 hours. The replacement cost from the manufacturer's agent is currently £230.00 Plus 20% VAT. . .

 

I have a friend here in the UK who is refurbishing these units, ( approved by the BMAA /LAA and Light Sport Aviation, the importers ) at a charge of £115..00 NO VAT. . . .and they are substantially better engineered than the originals. . Since they are not 'Brand New' parts, you could get them sent to Australia as a 'Gift' and pay via paypal PLUS a 10% commission to Ian since you heard about it on Recreational Flying. . . . [ You gotta send your old one though. . ]

 

( just joking )

 

 

[onetrack]

Interesting story, but I'm not sure it's all true

Oh, don't take my information as being 100% gospel, and with no inaccuracies.

I'm relying on information from memory from articles I've read, and many articles are open to dispute, and full of inaccuracies themselves.

 

We have to remember that we're talking about events of 75 yrs ago, events that happened within highly secretive establishments, and for the truth of many of those events, only a few collected memories of a few individuals are available.

 

Millions of documents that would have shed a lot more light on what happened between Packard and RR were burnt at the end of WW2, and shortly thereafter, so we are left with only a few tantalising insights from peoples memories (virtually all of whom are now dead) - and many statements and articles are open to qualification and challenge.

 

If we can have discussion without rancour and sneering, and aggressive dispute, we can generally distill the essence of the truth.

 

I do have a copy of a Warbirds magazine from the early 1990's, that had a decent article in it, regarding the Packard-Merlins engineering.

 

However, I'm currently on holiday and a long way away from home and my technical library, so I don't have access to it, at present.

 

 

[onetrack]

Re the "castings" vs "billets", vs "forgings" angle - this area will always create ongoing argument as to what style is satisfactory.

 

There are literally hundreds of millions of engines performing quite satisfactorily with cast steel crankshafts.

 

As always, the attention paid to the quality and handiwork of the casting is crucial. Impurities are the biggest bugbear in all types and styles of steel production.

 

Not a lot of people understand that scrap metal (of a known quality and purity) is essential to improve all types of steel production.

 

By adding substantial amounts of scrap metal (often 25%) of selected quality and known purity to a furnace whenever a steel pour is being produced, the scrap steel actually improves the finished product by a sizeable degree.

 

All freshly-mined ores of iron, contain impurities - even though the miners try to minimise them, and the iron-ore purchasers set specifications for levels of impurities.

 

Scrap steel has already been purified by going through furnaces, and having those impurities largely removed by high-temperature heating, by the addition of chemicals to actively remove many impurities (by turning them into slag via chemical reaction, that then floats to the surface, and is removed) - and by the addition of small percentages of the desirable, steel-fortifying metals, such as chrome, molybdenum, vanadium, manganese, nickel, etc.

 

The finished metal product is then produced to meet the specifications of an American, British or European metal standard, with the levels of the added constituents held within tight percentage ranges. A metal of high quality is noted for its tight adherence to the specifications standard.

 

A steel casting of good quality is quite acceptable for a very wide range of uses. However, once steels come under extreme stress, along with minimised weight requirements in the design, then a steel forging is a far better choice for the component.

 

Very high quality crankshafts that are subject to high power requirements are usually steel forgings.

 

In a forging, the metals grain structure flows with the shape of the finished product, reducing failures caused by the cutting of the metals grain - as happens in castings, and also in billets.

 

However, only the more sizeable manufacturers have the resources to be able to purchase and install forging machines, which are high-value items and also energy-intensive.

 

Thus, we find that only vehicle and engine manufacturers, along with dedicated component manufacturers, are often the only ones with the ability to produce items such as forged crankshafts, conrods, camshafts, and pistons.

 

Utilising a solid billet for a major component such as a crankshaft, gets away from the "casting flaws" problems of cast crankshafts - however, this option is the cheaper option to the better and stronger option of a forged steel crankshaft.

 

Using a billet is normally the choice of the manufacturers who can't afford forging equipment.

 

Interestingly, I found a copy online, of the blueprints for the crankshaft for the RR Griffon engine.

 

This blueprint was sold by an auction house that had no real idea of what they were talking about, and confusing the Merlin engine with the Griffon engine.

 

What I found interesting, was the notes on the blueprint (the photos can be blown up), related to very precise engineering and heat treatment procedures, that were to be applied to the crankshaft.

 

Careful attention was to be paid to radiuses, smooth finishes, no surface marks or scores, and final lapping to five decimal places!

 

In addition, the Griffon crankshaft engineering notes specify a billet of steel to be used - thus indicating that RR didn't have large crankshaft forging capabilities.

 

It is quite likely that the Packard-Merlin crankshafts were steel forgings, because Packard would more than likely have had the capability to produce large crankshaft forgings.

 

This then, would probably explain why the air-racers consider the Packard-Merlin crankshafts to be superior to the RR Merlin crankshafts, when they ramped the Merlins to extreme HP outputs.

 

Billet - Engineering definition - Billet - Engineering Dictionary - EngNet

 

RR Griffon crankshaft blueprints - Aviation Rolls Royce Merlin Crankshaft scarce technical drawing for the Griffon V1 series V12 aer

 

 

[turboplanner]

One thing which intrigues me is why there would be a need for 20,000 drawings.

 

 

[storchy neil]

so bex next time I'm playing a pussy oh cat needing a transplant can I call yah neil

 

 

[onetrack]

TP - There are probably two main reasons for the number of drawings;

 

1. Modification after modification, as the War progressed, and faults were rectified - and;

 

2. The simple fact that 27 variants of the Mosquito were produced, all designed for specific and different purposes - and amongst all those variants, there would have been another multitude of different equipment arrangements.

 

The Mosquito was the Willys Jeep of aircraft - just a lot more powerful, and a hell of a lot faster.

 

Just as the Jeep was re-purposed and utilised for dozens of different uses - ranging from ambulance, to rocket-launcher, to locomotive - so was the Mosquito utilised for a multitude of roles, many of which were never foreseen in the original plans.

 

De Havilland Mosquito

 

 

[onetrack]

Greg Goebels website is a staggering source of aircraft reference information - and here's his definitive and highly detailed history of the Mosquito.

 

Unfortunately, he has nothing on aircraft engines, just the aircraft themselves.

 

[1.0] Mosquito Origins & Variants

 

You will no doubt all be pleased to know, that I found the Mossie POH online.

 

You'll definitely need a copy of this, once you have your new Mossie finished, and ready to fly.

 

http://zenoswarbirdvideos.com/Images/Mosquito/MosquitoFB6Manual.pdf

 

 

[GraemeK]

You will no doubt all be pleased to know, that I found the Mossie POH online.

They were very careful to protect the secrets of the transponder!

 

"The demolition switches (69) for the IFF are on the electrical panel aft of the master switch (68)."

 

 

That would sure stop it squawking! Forget about 7700, just blow it up!

 

 

[fly_tornado]

apparently you can download some of the plans

 

Massive Cache of deHavilland Mosquito Plans Discovered

 

 

[onetrack]

Just reading all that Warbird page on Mossies is giving me wood!!

 

 

[onetrack]

I didn't realise there were so many videos of the Mossie on YooToob.

 

This one is the 43 minute, official De Havilland narrative of the development of the Mossie.

 

 

 

[johnm]

about 1982 ? when I was at a Motueka NZ flight school someone said there was a mozzie in a farm shed down the road

 

me and my mate went looking ................ sure enough we found it, asked Mr farmer if we could look - it was in good nick ................ with other aircraft (can't recall the others)

 

from memory the main wings and tail were on and standing on undercarriage ............and the elevators were off. we sat in the cockpit - it was complete (more or less) even the pilots handbook was there to read (something about if plane mishandled someway watch out the prop blades would n't break off ?!?) (thanks one track - item 66 of your POH ! - crash landing)

 

I'll try and find out where that mozzie ended up

 

 

[turboplanner]

Think I'll do a plywood session at Bunnings!

 

 

[Oscar]

Yep, Bunnings would suit you very well.

 

 

[facthunter]

There was money in it back then. People who made furniture got in on the act. My Tech Teacher at Tighe's Hill was one of them. Nev

 

 

[old man emu]

You've probably sen this, but it suits the thread.

 

 

 

[turboplanner]

I downloaded this from the link provided by FT. You could sure rack up a lot of drawings doing this.

 

Today we would just call this up on a Bill of Materials as Spruce - 2.0" x 1.0" x 43.60" to specification D.T.D 36B, Grade B, same as you wouldn't draw up a Bolt, 1/4" whitworth x 1" long, although Issue 2, which had a cutout in it would have required a drawing.

 

What used to happen until well into the 1960's is that we'd do a drawing, and in the Issue panel, would list the changes from previous.

 

The drawing would then go to Production Planning, or Planning department, or you may as a draughtsman have been required to fill out the change form which would consist of three columns, the centre one being, as shown in the Description, the left column showing the design to be deleted out of the assembly, and the right column showing the part to supersede it.

 

So on drawing C-9892, the planning document would basically look like this:

 

DELETE DESCRIPTION ADD

 

C-9891 Issue 1 Lower Crossmember - Rear Floor

 

Lower Crossmember - Rear Floor C-9891 Issue 2

 

It was a lot more complicated than that, but you get the idea. On complex changes the planning document could do your head in, and I've gone back and changed drawings at times to avoid that being the cause of mistakes on production.

 

What FT's link seems to indicate, by referring to microfiche of "drawings", "plans" and other descriptions, is that the cache may be a complete written history of the Mosquito, which would be priceless, and hopefully these old microfiche records, which could accidentally be lost in a fire will be carefully digitised for the future.

 

 

[onetrack]

I found a Wartime article on the Australian-built Mosquito, that states that De Havilland built the wings from laminated spruce and plywood - but the fuselage was built using NSW Coachwood, with Balsa inserts.

 

AUSTRALIA BUILDS MOSQUITO BOMBER - Newcastle Morning Herald and Miners' Advocate (NSW : 1876 - 1954) - 9 Jun 1944

 

I had never heard of Coachwood, but that's possibly because I'm not really familiar with all the range of NSW timbers - but apparently it is/was commonly used in furniture making, and as a veneer, because of its highly attractive colouring and grain.

 

Coachwood is also known as Scented Satinwood and Tarwood, with the former name coming from its caramel-like odour.

 

It's only of moderate structural strength - although it's referred to as a hardwood - and its lifespan, exposed, above ground, is regarded as short - around 7 years! This particular timber is now apparently becoming quite scarce.

 

Coachwood, also known as Ceratopetalum apetalum - Species

 

Ceratopetalum apetalum - Wikipedia

 

 

[Phil Perry]

Just reading all that Warbird page on Mossies is giving me wood!!

A 'Ply Wood' I trust ? . . .

 

 

[Oscar]

I found a Wartime article on the Australian-built Mosquito, that states that De Havilland built the wings from laminated spruce and plywood - but the fuselage was built using NSW Coachwood, with Balsa inserts.AUSTRALIA BUILDS MOSQUITO BOMBER - Newcastle Morning Herald and Miners' Advocate (NSW : 1876 - 1954) - 9 Jun 1944

 

I had never heard of Coachwood, but that's possibly because I'm not really familiar with all the range of NSW timbers - but apparently it is/was commonly used in furniture making, and as a veneer, because of its highly attractive colouring and grain.

 

Coachwood is also known as Scented Satinwood and Tarwood, with the former name coming from its caramel-like odour.

 

It's only of moderate structural strength - although it's referred to as a hardwood - and its lifespan, exposed, above ground, is regarded as short - around 7 years! This particular timber is now apparently becoming quite scarce.

 

Coachwood, also known as Ceratopetalum apetalum - Species

 

Ceratopetalum apetalum - Wikipedia

If you've ever handled a Lithgow-built SMLE .303 rifle, the stock is (at least, almost always) Coachwood. I believe that Coachwood was restricted from harvest during WW11 and for some time thereafter, for use in gun-stocks and presumably, also Mosquitos!. It is a lovely, very straight-grained timber that you could easily mistake for Hoop Pine, and it dries with very little warpage.

 

I have a small stand of Coachwood trees in a gully on my farm, and they grow -as per the piccy in the Wiki link - pretty straight, not much wastage after milling.

 

 

[facthunter]

Yes it was used for Rifle butts at Lithgow with the Lee Enfield 303.. Its fairly even grained and doesn't spilt like Rosewood (used for patternmaking) Hardwood / softwood is how the grain (Texture ) conforms to a generic type. Hardwood is a more open grain than say Hoop pine. Balsa is open grain and is a hardwood. Nev

 

 

[Allen Tromp]

[ATTACH=full]51487[/ATTACH]@benfarmerDT

[ATTACH=full]51487[/ATTACH]@benfarmerDT

I believe the photo shown in your article is of a Mosquito built by Mr. Glyn Powell and his team of volunteers in Drury, South Auckland, NZ. The aircraft now resides in Canada.

Anyone interested in the Mosquito project might wish to contact Glyn.

 

Having seen some of the construction at his workshop, I am astounded by the high quality of the work completed. Many component assemblies were constructed without original plans, using salvaged parts unearthed in various states of decay, from the four corners of the world, as patterns. It is a credit to the skills of the many craftsmen involved in the project, and an absolute joy to see airborne. Incredible given that in the day, everything was designed using pen and ink on drawing boards, and calculations done on slide rules -- Real Engineering, no computers - ( but then I'm of that era ).

 

 

[Frankus1aust]

I'll bet that the Chinese could make some. . . Oi, Bex ? ? ? ?

EDIT : Sorry Mr. Bex, I missed your post above ! . . .

Chinese ones would be only good for static display