Show me a photo of Gilman

p&p

Are current Merlins fitted with Gilman bearings ? Does this explain the engines apparent reliability?

No and yes and ‘don’t know’!

Steel backed shell bearings were a Gilman patent in 1938 but RR went for silver indium as an alternate to copper lead and didn’t have to pay royalties. I figure there was much cross pollination/theft of IP in the 30’s.
It’s hard to ascribe the successful interplay of many components moving at 2500 RPM to one singular design aspect or one single innovator, though the driving force of individuals such as Gilman at Allisons, Fedden at Bristols and the wandering ghost of Royce tended to create a great result.

Gilman is that most unAmerican contributor. This is no self promoter. I cannot find a photo of him anywhere and even the history of the Allison engine coy does not have one and provides a sense that he was a secondary figure. In terms of reliability the Allison of WW2 was very reliable. I figure a designer in California or New York understood an engine failure meant a three week trip on horseback to bring in a replacement for a busted valve spring, so things were sturdy. Things were easier to get to in Europe so a premium was placed on lightweighting and performance. This cannot be proven but you get to wonder when you look at an RR conrod that feels like a bone in a bird’s wing and then an Allison cylinder liner that could probably double as a mortar tube. Probably Russian engines are the same, same three week trip on horseback to change a spring.

I do not think an honest RR development engineer in 1938 would have had much confidence in the developing Merlin. Coolant leakage around cylinder liners was one issue. In the end, of course, a remarkable powerplant.

I have a BBC recording of a Mosquito doing a flypast during WW2 and it doesn’t sound like a Mosquito. I have seen KA 114 fly in NZ and that is a Mosquito ! A loud thing. But the BBC recording sounds like the 1908 Tunguska Meteorite impact meshed with the sound of 15 freight trains running over the foot of Godzilla ! Literally a bunch of 20 something pilots with a smile on their faces and the throttle full forward flogging the chicken crate across the sky. Good chance of punching a conrod out the side. I know I will never see something like that ever in my life. For good reason warbirds are run the way modern children are introduced to swimming, blue faced, anxious parents blowing up inflatable devices to keep them dog paddling in the shallow end. Merlins today have more medical imaging and cosseting than the entire heath budget of sub Saharan Africa in aggregate. The poor things don’t get a chance to be unreliable !

Stop asking questions that get me off topic ! No more questions requiring rambling answers unless you open your wallet and put some top shelf liquor on the table ! 😉