P-51 Mustang Merlin engine question.

[69427]

I've always wondered about the Packard built Merlin engine. Did they duplicate the RR engine completely, or did they use American bolts/fasteners in the engines? I'm under the impression that American bolt-size/thread-pitch was different than British bolts.

It's not keeping me up at night, but as an aviation enthusiast I've always been curious about this.

Thanks,
Mike

 

[Twin_Turbo]

Thread pitch is different, there are 2 sizes, fine and coarse, don't know the numbers off the top of my head. The therads have radiused corners too, withworth was stronger than a similar sized sae bolt.

Withworth wrenches indexing represent the thread size, not the hex size and the hexes are a different size for similar threaded un bolts so you need special spanners.

 

[TimAT]

I don't know for sure about the Merlin, but by convention, all of today's aircraft use SAE hardware- even the Scarebus uses all standard USA sized hardware.
the only place I've ever heard of Whitworth was on English-built cars.

 

[clutchdust]

No shit, Tim? The euro planes are using SAE? I'm stunned.

 

[mrvette]

No shit, Tim? The euro planes are using SAE? I'm stunned.

:bonkers: So am I, but Tim seen most of them, so.....:waxer: