I’ve been casting about for the last month or so accumulating research for an Italeri’s 1/35 PT build. Naturally, I started with the internet.
I’ve visited the PT at New Bedford, Mass., and, through a several decades interest, have formed what I thought was a reasonably well informed image of the boat’s major features. The motors, of course, were Packards…, eh?
I have now read that the engines were, in fact, Packard’s tweaking of the Rolls-Royce “Merlin” engine in an attempt (quite successful, it appears) to convert the British hand fitted design to Detroit’s mass production methodology.
While this is an appealing notion, and creditable to both sides of the pond, I wonder if anyone can direct me to confirmation of this assertion.
Before someone points out that this request of mine far surpasses any reasonable model building need, let me say that the research is, for me, half the fun.
Additionally, if anyone knows of a kit or plans for the Merlin itself, I would be delighted to learn of it.
Models are available from Engines and Things, for one, in 1/32. Armor scale I wouldn’t know. Likewise the Merlin at 150,000 examples which powered almost every British aircraft in WW2 you can think of. Named after the bird, not the wizard.
Allied Coastal Forces of World War II: Vosper MTBs and US ELCOs v. 2 (Conway’s naval history after 1850)
by John Lambert & Al Ross (google these names for their PT boat threads & sires as well)
This book has dozen’s of drawings of the PT boats, inc engines, which are Packard’s btw, & is the essential guide for anyone who wants to modify/scratch Italeri’s PT.
The Packard is, if you like the cousin to the RR Merlin, and there is a ‘strong family resemblance’, to the Merlin Areo engine with differences in fittings & gubbins!
I have read both that the engines were, and were not, Packard Merlins.
It turns out that Packard had long built V-12 marine engines for patrol boats (and racing boats) (well before they got involved with the license to build Merlins). So some of what I have read says that the PT boat engines were an upgrade of their existing line of boat engines.
It would be good to read a really authoritative article on this.
For what little it may be worth, I was a teenager during the WW2 years. Like most of my contemporaries I was avidly interested in things military (towards the end was a volunteer aircraft spotter). I have never heard of other than Packards as engines in PT boats. Specifically, the Rolls Royce information is news to me.
Thank you all for your comments and leads. It’s helped to refine my searches and there’s plenty of food for thought here.
But, you can see the source of my confusion.
I forgot that I had an unread copy of Norman Friedman’s, U.S. Small Combatants, collecting dust in my library (I’m glad I don’t have to buy that book today.). I think I need to add some Lambert and Ross material to it.
I do believe you should look up any info published by T.GARTH CONNOLLY on P.T. boats.This man knows his stuff , and , if I am correct , based on what I saw in 1959 at SAN FRANCISCO in a warehouse the P.T. there (undergoing repairs and refit to a civilian use) The engines were indeed the second series of PACKARD MARINE HIGH PERFORMANCE engines.They were having a hard time finding parts for them.The things were so massive looking I imagine those puppies generated lots of noise AND heat at high speed. Pity the engineman that had to play with those babies!! tankerbuilder
Bore: 6.375". Stroke: 6.5". Cu. In. Displacement: 2,490. Compression ratio: 6.4 to 1 (100 octane avgas). Red line: 3,000 rpm. HP (max) 1,500. Supercharged/intercooled.
Man, that’s gotta be loud!
Well, I think I’m beginning to catch up on my Packards. It seems, at first blush, that the Packard V-1650-1 through -25 (odd numbers) were essentially Merlins, but US Models (?, I assume meaning for installation in US aircraft).
The PT 4M-2500 motors only share the “V” configuration with the Merlin, and nothing else. Packard built a V-12 Aero engine during WWI called the Liberty engine (L-12) with a 1,650 cu. in. displacement, like that of the later RR Merlin engine. The L-12 engine was, in large measure, a product of Packard’s design people and sponsored by the US Aircraft Production Board.
Let’s start an International incident? Let’s suggest that the Merlin was a Packard design!
The only US PT with Merlins (Rolls Royce, not Packard) was PT 9, which was built by the British Power Boat Company and served as the basis for the 70’ ELCO design. From PT 10 on, US PTs were fitted with gthe 4M2500 Packard V12.
These illustrations are from the 4M2500 Operating Manual:
John included a large number of detail drawings of this engine in our ACF V2.
Early in the war, before Pearl Harbor, the brits were having a hard time ramping up production to the levels they felt they needed. They sent a mission to US to get planes and engines built here to their design. Packard agreed to build the Merlin aircraft engine, a V-12. Thus, the Packard Merlin, designed by Rolls Royce.
There are two versions about the PT boat engines. Some references say these engines were used in PT boats. Others say that while both were V-12s, the PT boat engine was an existing Packard boat engine design. And some say it was a Diesel, not a spark-ignition (gasoline) engine.
I would sure like to know for certain the whole story.
The only reference to a diesel engine for the PT boat (preliminary design work in 1937, with budget submissions for FY 1939) that I’ve sen s far is to a prototype GM diesel of 1,200 bhp in the blueprint stage. BuEng dropped the idea because the long lead time expected for development would have delayed the whole project. At this time, the proposed hull was 54’ and a supercharged Vimalert engine was chosen. All engines considered or adopted thereafter appear to be gasoline.
To further confuse the issue in some people’s minds, Packard also made automotive V12 engines. I was watching a TV show a few weeks ago as the two hosts were discussing a restored pre-war Packard automobile. When they opened the hood one said “And this is the famous Packard V12, the engine that powered the PT boats in World War Two.”
And the moon is made of green cheese…[whstl] Ya gotta love TV.
The 1937 Packard model 1507 is listed as being fitted with the standard-at-the-time V12 gas motor. Displacement is listed at 473 cubic inches. The 4M2500 displaces 2490 cubic inches…
Interestingly, Packard was the only major US effort to develop a diesel aircraft engine (for range). They built a prototype, and installed it in a plane ( I think a Curtiss Robin). But the sparkplug (Oh, bad pun!) behind the effort was killed in a crash of the plane and Packard scrapped the effort. I suspect that also may have killed any thought of Diesels for the high speed marine use.
The Packard M2500 had NOTHING to do with the Merlin engine. Packard was delivering M2500 to the US Navy in 1938 and Packard did not run its first merlin til Aug 1941 so how could the M2500 be a Merlin? and the M2500 was 50% larger than the merlin !!!
