Balance!

Thanks for the clarification, I suppose the the only conclusion one could draw, is that entries in the log book either match or don’t match sqn records.

an example of how a ‘soft’ object can grind away a ‘harder’ one.

You do see this quite a lot in engines especially pistons wearing out gudgeon pins; as has been said before improvements in lubricating oil and filtering could reduce the particals, but I do wonder about the crank cases and crankshafts (both of them) and their serviceability.

unless the Japanese have painted ‘Pearl Harbor or Bust’ down the side of one of their carriers

They did do that, but they wrote it in Japanese, and the Dutch couldn’t read it!

Could you not just reengineer the sleeve valve from scratch applying a modern solution but retaining the engine core layout or use a simple system like the Burt-McCollum sleeve valve?

According to wiki that is the system adopted by Bristol, it has been suggested that the centaurus sleeves were virtually identical to the sabre.

Tangmere, you are better positioned re p9374 than I, and I have no doubt that the new build hubs were expensive, and that the owner of th A/C could easily afford that amount also.

I am not really suggesting that making a prop hub from scratch is easy,( I would imagine it was machined from solid rather than forged, and that route is always expensive, because of the time it takes to remove 90% of the metal and the obvious wastage) what I was trying to do was make a comparison between the manufacture of a hub(s) and a sabre.

As you say it can be done (I never doubted that) but I do wonder if it will, and what the cost of running one will be.

It’s worth noting that Harry Ricardo considered the poppet valve dead end technology, (as must have Frank Halford) but they were wrong, the dead end was the sleeve valve, and the wear rate between the sleeve and liner has never been resolved, this is the main failing of the engine and it is inherent.

Reports that in cold weather, the engines had to be run every 2 hours to stop the oil congealing, dont exactly support the suggestion in DaveR’s post that the sabre was more reliable than the Merlin, an engine that made it’s name on the back of reliability!

The thing is though, the bracket propellor hub is a pretty basic lump of metal, and as you say reproduced at enormous cost; just think how much it would cost to build a sabre from scratch, and who would take responsibility for it, to the satisfaction of the CAA? leading on from that, are there even any potentially airworthy hubs that fit the sabre?

The driving forces in both restorations are American, the $pitfire has a universal appeal, and a base line value, the Typhoon is a largely ignored type (even in Britain) without the same parameters of market value; just look at the Shoreham sale some years ago, where a largely complete Typhoon cockpit section made significantly less than the “spitfire” mockup composed mainly of cardboard and chewing gum.

[I] ‘collectors’ (Whatever one of those is..)[/As a terminally infected enthusiast I]

I think you may have answered your own question