could the Allison engine have done what the Rolls Royce Merlin did?

[GregP]

I'd like to know the reason for that, very early engines with copper style HG needed the bolts torqued down then have the engine run up to temp and torqued a second time once cooled, I don't know why torqued bolts needed to be re-torqued over and over.

The reason for that is it is called out in the in-service manual. I didn't write it, but have seen it done and participated in doing it on several Merlins, all of which were in P-51Ds.

I knew one guy with a Spitfire, but he didn't let anyone else touch it unless they were part of his engine crew. I don't blame him at all.

 

[GregP]

Given that in this day and age the owners are using old parts, reconditioned parts, or re-manufactured parts and are essentially hand building the engine, I would think that more "fitting" is involved now than in the factory in period.

Very likely.

 

[GregP]

As I stated previously, I did not intend to start the RR vs Packard debate again. I was drawing (I thought) attention to Maurice Olley's recollection of events regarding Merlin and Ford.

A few facts.

Rolls Royce produced more Merlins than Ford and Packard COMBINED.

Rolls Royce produced 1411 Kestrels in 1936. 1937 saw a changeover from Kestrels to Merlins. I have compiled the following Merlin production table from various sources. Rolls Royce had produced ~24,000 Merlins by the end of 1941 while Ford and Packard had barely got started. As I have posted previously, the Merlin was the second most produced aircraft engine at that time, more than the much vaunted Liberty which was produced by 5 manufacturers and only exceeded by the Hispano V8s.

As can be clearly seen Rolls Royce was in full mass production well before Ford and Packard.

Rolls Royce increased their production by a factor of 10 in an incredibly short time. A magnificent achievement. It should be obvious that they did so by mass production methods.

View attachment 687005

The myth that Packard (or Ford) made a silk purse out of a sow's ear dos not withstand scrutiny and should be consigned with all the other fairy tales.

I've never heard ANYONE say Packard made a "silk purse of a sow's ear" when it comes to the Merlin.

I HAVE heard that Packard had to work with Rolls Royce on tolerances such that all parts were interchangeable. There's a BIG difference. Packard's Merlins were made with British fasteners and made to British specs. Rolls-Royce Merlins run very well and are not "better" or "worse" than a Packard Merlin. Equivalent models are just that, equivalent.

Don't make this any more sensational than it is. Rolls-Royce made Merlins. Packard and Ford made Merlins. If it were mine, I would prefer a Packard or Rolls Royce Merlin, in no particular order, to a Ford Merlin, but all were good-running engines.

 

[Frog]

Just my 2 c, Continental manufactured Merlins too.

 

[Shortround6]

I've never hear ANYONE say Packard made a "silk purse of a sow's ear" when it comes to the Merlin.

I HAVE heard that Packard had to work with Rolls Royce on tolerances such that all parts were interchangeable. There's a BIG difference. Packard's Merlins were made with British fasteners and mader to British specs. Rolls-Royce Merlins run very well and are not "better" or "worse" than a Packard Merlin. Equivalent models are just that, equivalent.

Don't make this any more sensational than it is. Rolls-Royce made Merlins. Packard and Ford made Merlins. If it were mine, I would prefer a Packard or Rolls Royce Merlin, in no particular order, to a Ford Merlin, but all were good-running engines.

Quite right.

Packard used British screw threads and even Whitworth threads/fasteners where the originals called for them to insure the best possible interchangeability.
There were things changed but the changes were sometimes due to bought in parts (sub-contractors like the carbs) and had always been discussed before hand.

 

[PAT303]

Not quite Packard was moving into Buick territory in the late 30s. See my previous post.
Post in thread 'An interesting read about the Packard built Merlin engine.'

What's interesting is the use of coolant tubes and seals between block segments on the Merlin, CAT 35 series engines use the same technique today and it's the most common engine in CAT mine trucks.

 

[Reluctant Poster]

This video has an old news reel showing how Ford maintained tolerances for their new V8 in the 30's. Start at the 14.30 mark. It is interesting to see that they weigh each piston and then use a special cutter to shave the inside of the piston to bring it into spec. They also weigh each con rod and piston together and them assemble then in matched sets. They also dynamically balance the crankshafts by shaving the counterweights and balance the flywheels by drilling holes.

 

[yulzari]

This video has an old news reel showing how Ford maintained tolerances for their new V8 in the 30's. Start at the 14.30 mark. It is interesting to see that they weigh each piston and then use a special cutter to shave the inside of the piston to bring it into spec. They also weigh each con rod and piston together and them assemble then in matched sets. They also dynamically balance the crankshafts by shaving the counterweights and balance the flywheels by drilling holes.

Is that not just production line hand fitting?

 

[GregP]

No, it is not production hand-fitting. Hand fitting is fitting a part to another part. Production tolerances are ensuring a single part is within tolerance, and therefore interchangeable with other parts. Big difference.

Fitting each of many pistons to within 0.010" is much different than fitting a single oversize piston to an existing cylinder with a known eccentricity and known dimensions.

 

[PBPICS]

Okay, here's one for the technophiles (definitely not including me). The Allison engine in it's various guises has always seemed to play second fiddle to it's famous contemporary in the land of hope and glory, the Merlin. Was there any intrinsic design feature that precluded Allison engines from powering single engine fighters over Germany at 25000 feet, of was it all just a case of the American engine being hobbled by the thinking of the time - that high altitude fighters weren't required?
To get full marks, please include an objective comparison of the beers of both countries.

As a former home brewer of craft beer, the devil is in the details. Excellent ingredients, meticulous technique, attention to details = excellent beer. Corn, rice as fillers don't belong in great products.
This actually relates to aviation in a direct way. I wouldn't want to fly in an aircraft or with a flight crew that didn't have those qualities as a baseline. Professionally speaking…in my former life as a tv news cameraman in New York…I'd take any opportunity to fly in any type of machine. It was mostly helicopters. Until there were several chopper crashes in NY and around the same time the news came out that the helicopter company that we used had the worst maintenance record in the region if not the country. I stopped volunteering to fly in their choppers while they were still being used. I will always love flying.

 

[FLYBOYJ]

As a former home brewer of craft beer, the devil is in the details. Excellent ingredients, meticulous technique, attention to details = excellent beer. Corn, rice as fillers don't belong in great products.
This actually relates to aviation in a direct way. I wouldn't want to fly in an aircraft or with a flight crew that didn't have those qualities as a baseline. Professionally speaking…in my former life as a tv news cameraman in New York…I'd take any opportunity to fly in any type of machine. It was mostly helicopters. Until there were several chopper crashes in NY and around the same time the news came out that the helicopter company that we used had the worst maintenance record in the region if not the country. I stopped volunteering to fly in their choppers while they were still being used. I will always love flying.

Just so you know the poster you're answering was banned over 8 years ago.