wuzak
Captain
What are the differences?
My understanding is that the initial production of Packard single stage engines differed from the equivalent Rolls-Royce engines in minor details only. Such as the sealing between the head and the block. Which was changed to match the Rolls-Royce engines later.
The two stage engines differed in having a Wright designed epicyclic supercharger drive system, as opposed to the Rolls-Royce Farman type.
Packard engines going to the USAAF had SAE splined prop shafts, those going to the UK/Commonwealth had SBAC shafts.
From another thread:
Packard Merlins were surely built to Rolls-Royce drawings, even if they had to be redrawn for American conventions. So I can't see why Packard Merlins were "built to more stringent standards".
Apart from the eronious term "file to fit", did Rolls-Royce production Merlins (as opposed to those built in the experimental shop) have parts individually fitted? I have my doubts, especially for engines built by Ford UK.
Now, the Packard Merlins all had equivalent Rolls-Royce engines, and were rated according to the Rolls-Royce ratings.
V-1650-1 = Merlin 28
V-1650-3, -5, -7 were 60 series engines.
V-1650-9 and later were 100 series engines - with strengthened components.
An example of the supposed superiority of the Packard built engine was the V-1650-9. With water injection and +30psi boost the -9 delivered just over 2200hp.
The equivalent Rolls-Royce engine (RM.16SM) was not fitted with water injection, and was limited to +25psi boost and just over 2000hp. With ADI the other 100 series Merlins could, surely, match the 2200hp of the -9?
Just how much engine development did Packard do on the Merlin?
Finally, the RM.17SM was cleared for flight at 2380hp with +30psi boost @ 3300rpm (I assume with ADI). It was to be rated at 2200hp @ 2000ft MS gear and 2100hp @ 15,000ft FS gear. I believe both were at +30psi and 3000rpm.
And the RM.17SM was tested for 15 minutes at 2620hp, +36psi boost, 3150rpm with ADI.
My understanding is that the initial production of Packard single stage engines differed from the equivalent Rolls-Royce engines in minor details only. Such as the sealing between the head and the block. Which was changed to match the Rolls-Royce engines later.
The two stage engines differed in having a Wright designed epicyclic supercharger drive system, as opposed to the Rolls-Royce Farman type.
Packard engines going to the USAAF had SAE splined prop shafts, those going to the UK/Commonwealth had SBAC shafts.
From another thread:
Packard Merlins were built to Rolls-Royce specs and standards.
No, they were not. There were built to more stringent standards.
Packard Merlins were surely built to Rolls-Royce drawings, even if they had to be redrawn for American conventions. So I can't see why Packard Merlins were "built to more stringent standards".
Parts built by Packard were interchangeable with parts made by Rolls-Royce and Ford UK.
Not all parts in all equivalent engines. R-R still had many hand fit parts and much "File to fit" in their engines.
Apart from the eronious term "file to fit", did Rolls-Royce production Merlins (as opposed to those built in the experimental shop) have parts individually fitted? I have my doubts, especially for engines built by Ford UK.
Now, the Packard Merlins all had equivalent Rolls-Royce engines, and were rated according to the Rolls-Royce ratings.
V-1650-1 = Merlin 28
V-1650-3, -5, -7 were 60 series engines.
V-1650-9 and later were 100 series engines - with strengthened components.
An example of the supposed superiority of the Packard built engine was the V-1650-9. With water injection and +30psi boost the -9 delivered just over 2200hp.
The equivalent Rolls-Royce engine (RM.16SM) was not fitted with water injection, and was limited to +25psi boost and just over 2000hp. With ADI the other 100 series Merlins could, surely, match the 2200hp of the -9?
Just how much engine development did Packard do on the Merlin?
Finally, the RM.17SM was cleared for flight at 2380hp with +30psi boost @ 3300rpm (I assume with ADI). It was to be rated at 2200hp @ 2000ft MS gear and 2100hp @ 15,000ft FS gear. I believe both were at +30psi and 3000rpm.
And the RM.17SM was tested for 15 minutes at 2620hp, +36psi boost, 3150rpm with ADI.