Quarter Scale Merlin V-12

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Of the engine castings or the guys days in postwar England?
It is a misnomer on both counts. It was never 'post war England'. WW2 as such waa over but in months our former Allies were our enemies. Conscrpription in the UK lasted and lasted as did rationing and the last of the conscripts would have been born in 1938 and those who survived would be old ruins like me in mid 80;s and errrrrrr older! Many would die s fresh faced youths in the many conflicts from Russian occupied Berlin to as ffar as the Far East. Communism was rife and deaths on- as a WW1 poet would have said 'On a Foreign Field that is for ever England' I'm sorry but as someone who was in a bit of it after 6 years of WW2, I was there watching some of us horribly burn to death- and would be forgotten.
Our Forgotten 14th Army and an unarmed RAF 31 Squadron would echo the words from the Greek:-

When you go home
Tell them of us
For your tomorrow
We gave out today
Again with the closing of WW2 in Europe and long before Enola Gay would change the World forever, the Merlin engine was dead. Our Sptifires would not escort both American and British bombers and the up rated American P-51D's fitted with American Merlins were no match against the Ferman jets and rockets which were coming 'on stream/. Thankfully bombing by Allied and British bombers had reduced them. But the V1's and then the V2;'s ere getting through- and I slept for most of my conscription in a 'Doodle bugged' billet. All this ballyhoo about tipping a V1 with obsolete Spitfires and on stream Typhoons and coming on Stream Meteors was largely journalism. It was not until the launching sites were overun by the poor bloody infantry that the attacks ended.
By the end of what people call the end of WW2, the famous Spitfires were resigned to 'Toy for High ranking officers' and Auxiliary weekend airmen who had the vast life expectancy of 400 hourd flying time.
By 1960, even these venerable little jockey fellows would be flying DH Vampires.

All that would be left were carrier borne Seafires in Korea being hopelessly out gunned by jet powered Mig-15's over Korea.
By September 1949- I had reached the dizzy heights of the rank of Hitler and Napoleon and hd lready seen my 'boys'( they were all older than me) die= there was a job in the deveping British civilian aircraft industry in a scant few months. What did we have to show the World and me at farnborough Air Show?
And these Meteors would become - widow makers, the much vaunted Brazon out of Filton would end as scrap and the then thrilling DH Comet 1 would shake itself and everyone on board- to death in a year.
Perhaps wisely, I had seen enough and would switch to running my own little air travel business- on the side and in my lunch hours( 20 minutes) and I watched prices of property prices go into orbit. Like that Meor with the re-heats? I would fly comfortably and reasonably safe at a faster speed than was ever achieved in level flight in the best of Spitfires with filed rivets whatever.
Five years aho, I did what a decent old survivor would do.

The Brits now have a National Arboretum to recall those who did their best and paid their efforts in death for you and me. There is the Star of India which lists the commanding officers who led from long before the Royal Air Force was concocted- from the cavalry. Perhaps I am the oldest survivor now of a Squadron that is only a fading memory. People get old or the lucky ones do and a seat is always welcome. As Sole Executor and sole beneficiary and Trustee, there is a simple wooden seat- from my wife to her Dad- who was part of it.
I'm still making money from air travel and , as I don't want it- apart from the fun- am giving it- like my mates to deserving charities- much of it to the other survivors from those dreadful days.
My story, my events, my life --- because I was THERE.
What kills me the most is that the US offered surplus P-51's for $100 a piece in 1946. After the Korean war they re-offered them for $500. Imagine the investment if you tucked a hand full of those in your back yard!
The only coolant system sealer I've ever used was "Alum-a-seal"

my father also introduced me to the stuff. Even would seal a small head gasket leak long enough to get you home. Amazing stuff!

one small 1”x3” tube would do the trick.

What kills me the most is that the US offered surplus P-51's for $100 a piece in 1946. After the Korean war they re-offered them for $500. Imagine the investment if you tucked a hand full of those in your back yard!

This echoes the book about a pair of Merlins in a gunboat after the WW2 as Nicholas Montserrat's the Dhip that Died of Shame. So long ago, and I almost forgot!
I recall the Wembley Cup match 1949 and the hundreds of Government surplus aircraft that were parked around RAF Hendon for the matc'h. They were then 'dirt cheap- beyond my pocket, of course.
The years moved on-
there w as 31 Squadron's annual reunion and ex- officers in their rusty old cars and a once scruffy sergeant and I paring our gleaming Mercedes as far away as possible from them. Roly Sahib was the owner of a scrap yarf on the Tyne-- and I was -rather well off with a small trave business and property abroad-- and all that I had had previously was a Govdernment surplus Royal Observer Corps uniform with only a cap badge, a pair of chevrons and 'seagulls' on the shoulders.

But men are also forgotten and a Royal British Legion branch- an important City one and it was £30, 000 short and ready for closure and there once heroes would be dumped. I was a member who never had time or inclination to attend but they got £15,000 from my little group. of just over 3,000 Freemasons to help.
The World changes- men as well as P-51D's are forgotten but more importantly the men and women.

In the story of the engine fitter of SL_721 JM-R he was deafened by one of the 3 Spifires. I finally got him a War Pension 50 years after his ears had been blown out.
It took our Government 70 years to get us both hearing aids.
So I must agree most strongly and Thank You

Hi Jennifer

Thank you for the information but I always thought that R_R stuff was Hylomar:)

Are you still perched in Brid? Family are - when there is a chance on the windy end of Flamborough Head.

Best Wishes

Well, I have spent the last couple weeks collecting manuals on the Merlin. Also studied the Ramm videos of his engine running in Australia. He does not document the build at all, but it is obvious he worked out the cooling issues. I have owned several V12 Jags...and honestly the cooling is very similar. The thing to remember is the Brits are very big into external piping. We Americans always look for ways to do it internally...and often miss the obvious. Cooling is plumbed differently on pretty much every aircraft in which the Merlin was installed. I will have to lean towards the P51D for my build, naturally.

Making headway on digitizing all the parts too. I will have to CNC the entire rear gearbox and supercharger sections.

Also starting to collect metal for the non-cast parts. I plan to stick with the phosfor bronze on the bearings (can't bring myself to use silver on a wearable part, although bronze costs almost the same these days). The crank and prop shaft will be 4340 steel. I am sure that is overkill, but 4340 is still the premier metal for crankshafts in any engine.
I am restoring a full-size, wrecked 1940 Stearman, which is taking most of my time. I am still working on programming the castings into Inventor during odd times. Once I am ready to start, this project should go a lot faster than previous endeavors with these castings, using CNC and thread-milling instead of 2000 tapping operations. All but the cylinder blocks are now programmed into the virtual world of CAD.
Yes, I have the proper thread mills all purchased and ready to go. The biggest issue I foresee is the tiny drill bits gumming up with the aluminum. I'll have to find the proper mix of speeds, feeds, and lubricant.
The problem I ran into is that for several of those castings with all their screws, the bosses for them weren't precisely spaced for whatever reason. Since I wanted the screws in the exact center of their boss, I indicated each under a spindle microscope. While I was there hovering over the boss, it just made sense to go ahead and spot and drill the hole. I also had to heat straighten nearly every casting of any significant length that typically had long rows of screws. The Merlin will fight any attempts to automate its construction, and you'll have to have the patience to play by its rules. I'm a fan of CNC, but it just wasn't useful on this build.
Make sure of what you're doing on those heads with the dimensions that don't agree with the drawings. I had the same problem, and the changes you'll have to make to your drawings will spill over into the rest of the engine and many of the drawings of other parts will have to be changed, and you'll be compensating for those changes during the entire build.
It's my understanding that the head castings were so troublesome to manufacture that they almost tanked this project. My drawings in fact included a set of functional but esthetically poor looking heads that could be machined from billet. These were provided to builders as a back-up plan in case the cast heads never materialized. I also spent countless hours digging investment out of its coolant passages. You'll need to study the intentions of the coolant system in the head and make sure the passages are connected and free-flowing as they should be. Mine weren't and required a lot of remedial work. - Terry
That's why the digitizing has been going so slow. As you say, each screw boss is off a bit...I have been taking the time to mic each difference as I digitize the castings into Inventor. The flip side is that, as you note, Terry, my programming likely will not work on any other set of castings.

I only have the basic drawings, and finding the missing ones is no longer an option since Dyno has distanced himself from the project. It's a shame he wants to lock in the copywrite to prevent copying, yet he won't sell them either. That may be a blessing for my project, as my castings will be completely digitized, so I can work on size and placement issues long before the first cutter touches aluminum. The other beauty is that I can run the final program without a cutter to track the accuracy, and only once all the bosses are located exactly run the cutters.

The trade off is I am spending the many, many hours on the computer to save hours on the mill. I am likely spending more total time, all said. We'll see how it goes once the Stearman is out of the shop.
As an apprentice, one of my early machine shop supervising artisans gave me some sage advice - he was watching me charge into a job without really thinking it through and he said "You can't put the machine in reverse and put the material back on !".
That thought always hovers into my mind each and every time I take a cut.
Sadly it hasn't always stopped me making mistakes.
But time spent planning sure as hell beats time spent remediating errors.

Regards, Ken
As an apprentice, one of my early machine shop supervising artisans gave me some sage advice - he was watching me charge into a job without really thinking it through and he said "You can't put the machine in reverse and put the material back on !".
That thought always hovers into my mind each and every time I take a cut.
Sadly it hasn't always stopped me making mistakes.
But time spent planning sure as hell beats time spent remediating errors.

Regards, Ken
Grin - - - - that's one reason my welding skills also improved!
Here's the Stearman. A before and after on the frame. Long way to go...


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Hey Jos,

The Stearman wings and tail are even worse! They are put up in storage. Since I am working out of a 2 car garage and can only work on one part at a time. Here is a picture of how the plane came to rest...pretty much says it all!?!

Back to the Merlin, The relatively new "AirCorp Library" website now has some very good information on the Merlin. In addition to a complete set of detailed drawings of the entire engine, they have all the associated manuals. They even have complete factory drawings of most WW2 aircraft. In fact, I am toying with my next project to build a P-51 right off the original plan sets! All the destroyed parts on my Stearman can be duplicated from the original Boeing drawing sets. All this available for almost nothing...yet Dyno won't let us copy his papers?!? The second picture is one of the broken flying wire lugs that I pulled off the Boeing plan and CNC'd from 4340 steel. I think it's pretty cool all this information is at our fingertips!

Anyway, I am missing the rear gearbox castings from the 1/4 scale set I bought. The great thing is that I can reference the original drawings that Dyno likely used. That will actually simplify my project, as the castings wound up being a bit of a disaster...shrinkage appears to be what killed the entire project. Using CNC from factory drawings, and machining from billets, all those issues can be avoided. At least that's the plan...I'll keep everyone updated when I finally put the tools to the metal...


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