During 1942, several Spitfire V’s suffered something termed a Skewgear failure. I’m not an engineer, but from a drawing in Alex Henshaw’s book Sigh for a Merlin it appears that the Skewgear forms part of the linkage drive from the main prop shaft to the Cams, possibly also linking in the magneto’s. The problem was finally tracked down to a production line fault at one of Rolls Royce’s contractors
From Alex’s book it appears many of these failures happened during testing and pre delivery flights. My question is does anyone know if these engine failures happened to operational aircraft ? I’ve read about Mk XVI’s suffering engine failures because of a production fault within a batch of Packard built Merlin’s, however I can’t recall anything being recorded about similar “operational” problems with the MkV.
Any input would be welcome.
By: fidgit1 - 30th November 2005 at 13:51
When a friend and I were at Alex’s house some years ago, he showed us one of these skew gears mounted on a wooden plinth which had been presented to him by, (I think), Rolls Royce as a momento(?) of the in-flight failures he had suffered!
By: steve_p - 29th November 2005 at 22:50
I thought that one of the problems was due to sloppy procedures on the US production lines. I’m sure that it involved the US workers emptying their cups of Coke into the manufacturing machinery. 😮
Best wishes
Steve P
By: EN830 - 29th November 2005 at 22:43
I wonder if Alex’s summary of flying 12,767 aircraft is any kind of record ?
By: EN830 - 28th November 2005 at 19:12
According to Sigh for a Merlin the serial numbers tie in with Mk V’s, the serial of the one that he nearly lost his life in “EP615” was reallocated to a MkIX. Alex suffered quite a few Skewgear failures, certainly more than two. In all he made 127 forced landings at Castle Bromwich, not all in Spitfires.
By: proplover - 28th November 2005 at 18:07
I thought the problem was with the early Mk IX’s? I seemed to remeber Alex had to force land at least twice due to this problem – one ending up going thru a house.
By: dhfan - 28th November 2005 at 14:55
I had an idea Sigh for a Merlin said assembling the components in a different order resulted in the backlash not being correct but it’s a couple of years since I read the book.
By: Ant.H - 28th November 2005 at 14:38
I read Sigh for a Merlin a few months back,and as I remember it the cause was never specifically determined. There were several contractors building screwgear assemblies for RR and it was discovered that all the failed units were assembled at one particular factory. It turned out that although the finished product was the same,they were assembling the various parts in a different order to the other contractors. It was never worked out what specific difference this made,but once this contractor started putting things together in the textbook order the failures stopped.
By: Bruce - 28th November 2005 at 10:13
As I recall from the book ( and I must read it again), the failures occurred on MkV aircraft, so they would not have Packard engines. Was it not something to do with machining tolerances on the skewgear?
Cheers
Bruce
By: steve_p - 27th November 2005 at 14:41
I think that this topic was also covered by Henshaw in a set of articles in Aeroplane Monthly at some point in the 1980s. If I remember correctly, the fault occured with Packard Merlins.
Best wishes
Steve P
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November 27, 2005 at 2:26 pm