Building a Merlin engine.

[abowie]

This is the second in the series.

Really interesting discussion about reusing big end bolts and split pinning them.

[Gfhug]

The info is probably somewhere in the KB but do we know the reason why Jaguar went from using split pins to the locknuts on the big ends which are now shown as what must be used? Any reflection on Merlin’s being built by well trained engine technicians? Though they went into mass production by the likes of Ford and Packhard during the war.
Are the locknuts a more modern product that makes the task easier and has one less component that might be assembled badly?
Any of the knowledgable able to answer?

Geoff

[christopher storey]

Geoff : I think that Jaguar abandoned the split pins because of numerous instances of them breaking off , getting into the oil pump and being shredded and then fragments going through the bearings with disastrous consequences

PS you might be interested to know that the Ford Trafford Park Merlin plant had the best results of all the Merlin assemblers, and I was once told by Sir Rowland Smith ( who ran the plant) that they were taken aback by the high tolerances that RR Derby tolerated ( pun intended )

[Gfhug]

Christopher, have you read “Not Much of an Engineer” by Stanley Hooker? Supremo of supercharger design at RR. If not you must. Great reading for anyone interested in engines, piston and jet.
He relates how when the Merlin was being discussed for production by Ford that they told RR they couldn’t work to RR’s tolerances. Of course RR looked down their noses at a mere humble company like Ford and assumed the tolerances were too tight. Actually it was the reverse as Ford needed tighter tolerances to allow for mass production techniques rather than the assembly by far more experienced and trained technicians at RR.

Going back to the problem of broken split pins, could that be due to lower quality allowed for car manufacturing versus aircraft?

An area for interesting discussions regarding quantity production giving greater quality through the need of reliability for mass production against the higher specification for aero-engine parts.

Edited to add: I’d have thought Hooker and Sayer would have worked well together as both were very theoretical engineers working with slide rules to fine aerodynamic principles. Hooker would have recognised the diagrams and equations Sayer used to draw the lines of the E Type.

Geoff

[christopher storey]

Geoff; I have indeed read Hooker's wonderful book several times. I could be wrong but I think that his and Sayer's paths might well have crossed when both were at Bristol Siddeley and before Sayer went to , was it Baghdad?

[rfs1957]

Well, I never go to The Pub but have obviously been missing something.

You bloody Influencers, you've just cost me the price of ordering Hooker's book, and the time spent watching two episodes of the Merlin assembly.

My only interrogation would concern his use of a nylon-faced mallet to seat the bolts, when by definition what you want is the sharpest jerk possible, far better obtained surely with an aluminium drift and a steel hammer?

But the torquing of the bolts into the plastic phase is a concept I was completely unfamiliar with, tho' I have had on my desk for 10 years a very erudite paper that justifies this....... only every time I try to read it I get a headache.

Regarding planes, I got to within a bank transfer of buying a part-finished Rutan Cozy IV from the US about 10 years ago, whilst working towards my PPL, but the seller pulled out at the last minute.

I have never worked out whether this was a bullet dodged, or a sad opportunity missed.

The Jag would never have got restored like this if I'd gone airborne, so I probably should conclude that I dodged one bullet only to get hit by another

[Gfhug]

Rory, please report back after you’ve read Hooker’s book. Then if you’re further interested the Rolls Royce Heritage Trust has several excellent books written by people who helped design, develop, build and maintain the Merlin and other RR engines. Bedtime reading for you

Christopher, Simon P and I, plus others on here have gone down both routes, aeroplanes and E Types. Two bottomless money pits but masses of fun along the way.

Geoff

[Herzeg]

Geoff

You are right that planes and E-types can be money pits, but, as one who is now considering going flying again, at least you don't need annual medicals and ECG's to drive the e-type!

John