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> Funnily enough from RAS (Reliability, Availability, Serviceabilty) British liquid cooled engines beat American radial engines so hard it wasn't funny. Presum

by jabl 4y ago

> Funnily enough from RAS (Reliability, Availability, Serviceabilty) British liquid cooled engines beat American radial engines so hard it wasn't funny. Presumably you mean the Merlin and not, say, the Sabre? :) But anyway, that's interesting, haven't heard of that before. Do you have some more information on this topic? From what I've read Americans were shocked to find out how 'hand built' the Merlins were, with pretty large differences between each engine, engines being delivered with metal filings in the crankcase requiring inspection and cleaning and whatnot. So a large part of the work Packard did for the license produced Merlin was tightening up the design so it could be mass produced much faster on production lines. Of course this doesn't prove the RAS point you made one way or the other, but it seems strange that if Americans put so much more emphasis on efficient production that they wouldn't have put similar effort into serviceability?

p_l 4y ago
The issue with Merlins was that Rolls Royce was manufacturing them whenever and by whomever by the time war got into full swing, which easily explains the differences between individual engines. As for serviceability, the difference was in design - American engines were effectively "thrown over the wall" to airplane designers, resulting in such beautiful designs like B-17, where IIRC inspecting or changing a sparkplug started by removal of propeller because apparently even good idea fairy was out drinking when they designed it. In comparison Rolls Royce designed a standard "pod" for the engine that would be then minimally adapted by plane designer, with an eye towards servicing and commonality. So the tolerances might have been tighter on US production lines, but little thought was placed at least in some designs on how to support operations on the planes instead of just building them. (Something that arguably is present today with F-16 at least, and possibly F-35 too)
- jabl 4y ago
  > So the tolerances might have been tighter on US production lines, but little thought was placed at least in some designs on how to support operations on the planes instead of just building them. (Something that arguably is present today with F-16 at least, and possibly F-35 too) Not too familiar with the maintenance requirements of the F-16, but admittedly having a hydrazine powered APU is a pretty WTF design choice.

by jabl 4y ago

p_l 4y ago

The issue with Merlins was that Rolls Royce was manufacturing them whenever and by whomever by the time war got into full swing, which easily explains the differences between individual engines. As for serviceability, the difference was in design - American engines were effectively "thrown over the wall" to airplane designers, resulting in such beautiful designs like B-17, where IIRC inspecting or changing a sparkplug started by removal of propeller because apparently even good idea fairy was out drinking when they designed it. In comparison Rolls Royce designed a standard "pod" for the engine that would be then minimally adapted by plane designer, with an eye towards servicing and commonality. So the tolerances might have been tighter on US production lines, but little thought was placed at least in some designs on how to support operations on the planes instead of just building them. (Something that arguably is present today with F-16 at least, and possibly F-35 too)

jabl 4y ago
> So the tolerances might have been tighter on US production lines, but little thought was placed at least in some designs on how to support operations on the planes instead of just building them. (Something that arguably is present today with F-16 at least, and possibly F-35 too) Not too familiar with the maintenance requirements of the F-16, but admittedly having a hydrazine powered APU is a pretty WTF design choice.