Warbird Information Exchange

Hello,

I’m wondering myself about the difference between the packard built Merlin 266 in the spitfire mk xvi and the packard 1650-7 in the mustang. I have found some informations about improvements done by packard to the merlin 66 in order to adapt it to the american assembly line but nothing about differences between 1650-7 and 266, except both engine are derived from Merlin 66. Is it possible to swap theses engine in a p-51d or spitfire? Roush improvements developed for the 1650-7 are also suitable for the 266?


Thanks for yours answer and fly safe!

Pyog

Redacted, I'm not as familiar with the 266 as I first thought.

From what I gather the 1650-7 was optimised for high altitude while the 266 was optimised for low-medium altitude. The 1650-7 was based on the Merlin 66, and as the 266 was just a packard built Merlin 66, I would ASSUME that some parts would be interchangeable.

Also Keep in mind that the the term V-1650 was the U.S. standard of engine classification. "V" design, 1650 cuin dispacement, while Merlin 266, 66 etc was the British terminology. Could possibly be that the V-1650 and merlin 266 are the exact same engine, just assigned different names based on who purchased it. Similar to P-51D vs Mustang MkIV and P-51K vs Mustang MkIVa.

I am by no means an expert, so I am sure there will be others with a much more detailed, and most likely more accurate answer.

Sean

Rather surprisingly, I can't find chart that compares the products of the two builders.

I would imagine Roush Aviation could answer your questions.

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As I understand it, not only Packard but also Ford redesigned the Merlin for American mass production. The Merlin had been designed with "backwards compatibility" in mind which meant that there were a lot of adaptors to make things fit between the different mark numbers. A starter from a Merlin 32 could be made to fit a Merlin 45. Packard and Ford redesigned the engine from more or less scratch and that interchangeability (is there such a word) was sacrificed on the alter of mass production. I don't know if a V-1650 would fit in a Spitfire Mk XVI or if a Merlin 266 would fit in a P51-D but I'm pretty sure that a starter from one wouldn't fit the other.

IIRC, one of the conditions of the license agreement was that Packard engines were supposed to be interchangeable AS A UNIT with RR built engines.
While the individual components, accessories and such were different, the mounts, inlet and outlet fittings for fuel/oil/coolant were supposed to allow dropping a US built engine into a British built airframe with no modification required.
How that actuall worked with divergent evolution of applications, I don't know, but that was supposed to be a key feature.

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Lest Hero-worship raise it's head and cloud our vision, remember that World War II was fought and won by the same sort of twenty-something punks we wouldn't let our daughters date.

Well, thanks for yours answers. I have a second question do you have any idea which overhaul workshop is providing engines for operators performing commercial flight like stallion 51, boulbee academy, colling?

Thanks!

Pyog

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While I can't exactly answer your question, this chart may help some. It is from page 201 of "British Piston Aero-Engines and Their Aircraft, by Alec Lumsden, 1994. The bottom chart says that the 266 was the V-1650-3 equivalent. For what it is worth.

Randy

Added from page 213 of the same source.

"MERLIN 266, 1,315 hp. This two-speed, two-stage engine was a Mk 66 with the same ratings but built by Packard. With the same ratings, it was a low-altitude engine. It had the usual Packard features, interconnected engine controls and Stromberg injection carburettor. Propeller reduction gear .479:1. Rating RM.105M"

For the 1948 Thompson Trophy races at the Cleveland Air Races, Anson Johnson had replaced his Mustang's V-1650-3 for a "V-1650-225, the same engine used in the DeHaviland Mosquito" because he thought it "was better suited to his purpose by virtue of its lighter weight and better sea level performance."....Journal American Aviation Historical Society, Winter 1974
Johnson won the 1948 race by pacing in fourth position and having the Super Corsairs and Cobra II pull out with mechanicals.
He further modified his Mustang for 1949 by removing the oil cooler doghouse.

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Many thanks it is just perfect!