WIX Archives

Re: Shackleton/ Griffon Spitfire Question?

Posted by Christer on Sun Jun 30, 2002 12:08:49 AM

In reply top Shackleton/ Griffon Spitfire Question? posted by Ray Crawford on Fri Jun 28, 2002 09:00:30 PM

Hi Ray!

The Griffons fitted to Spitfires, with the exception of the Mk.XII, had two stage, two speed superchargers. They developed something like 2.050 hp on +18lb boost (RR-G 61/65/66) and 2.350 hp on +25lb boost (RR-G 64/67).
+18 was available running on 100/130 grade fuel whereas +25 required 115/145 grade.

The Griffons fitted to Shackletons (RR-G 57/58) had a single stage, two speed supercharger. They developed approximately 2.400 hp on +25lb boost running on 100/130 and water/methanol injection.

The single stage engines are shorter than the two stage variants. This means that the neck of the inlet air ducting has to be modified to fit a single stage engine to a Spitfire. Then, as You pointed out, there?s the reduction gearing which has to be modified from contra rotating to a single left hand tractor.

All BBMF Mk.XIX's have had this modification, PS915 was used as a test bed long before it was rebuilt to fly.
If I recall correctly PS853, now owned by Rolls-Royce, was the first to be modified, PM631 the second and PS915 the third during its rebuild.

The Planes Of Fame PS890 has a RR-G 58 fitted, still driving contra props, which makes it more cost effective and quite a unique Mk.XIX.
I assume that You know that not only Seafires but also a few Spitfires had contra rotating propellers "in the old days". These were two stage, two speed variants of the RR-G 80-series.
The Merlin 66 of the Mk.IX was also modified with contra rotating propellers but I don?t recall the proper designation.

The price tag on a RR-G 58 complete with propellers, well, I know that it?s only a fraction of the cost to acquire and rebuild the original RR-G 66 and its five-blader. Something like 1/5 but, I can?t give a precise value.

Hope this helps a wee bit!

Christer
(masquerading as a british aircraft expert)

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