Development Potential of Bristol Mercury and Pegasus engines

That's along the lines of what I wrote in Post 14. As part of some research for another thread I recently discovered that both the French and Italians tried to develop more powerful versions of the Jupiter, Mercury and Pegasus by adding cylinders, but with varying degrees of success. E.g. the Piaggio P.108 was fitted with a development of the Bristol Jupiter producing 1,350hp, but it was not reliable.

(my bold)
Quirk is - there is no such thing as adding cylinders so one can get more power. More cylinders means new items: crankcase, crankshaft, master crankpin, supercharger, carb, reduction gear, intake manifolds, ballancers, valve opening/closing sytem - and now we're talking about new engine. The legacy cylinders' finning will not allow a significant increase of RPM and boost pressure before overheating, unlike the new ones. Cooling of the second row with legacy cylinders?

Now, to the OP: Bristol might remeber the inter-war experiments with 2-stage supercharged & intercooled engines, that fetched them several altitude records, and try to come out with a 'military-proof' 2-stage versions of the Pegasus/Mercury.
 
Strictly speaking the Piaggio engine was 2 Jupiters in tandem (and Alfa Romeo put two Mercury's in tandem to make an engine producing 1,350hp) but I take your point.

Although I'm no engineer it looks similar to trying to turn the Kestrel into the Vulture and the Daimler Benz coupled engines and it looks as if Alfa Romeo and Piaggio were about as successful.
 
The Gnome-Rhone Mistral 14 cylinder two row radial was developed from a licenced Bristol Jupiter. Therefore developing a two row version of the Mercury should not be beyond the bounds of ATL engineering.
 
Strictly speaking the Piaggio engine was 2 Jupiters in tandem (and Alfa Romeo put two Mercury's in tandem to make an engine producing 1,350hp) but I take your point.

Although I'm no engineer it looks similar to trying to turn the Kestrel into the Vulture and the Daimler Benz coupled engines and it looks as if Alfa Romeo and Piaggio were about as successful.

Although I have been described as a contrarian, in this case, it was Roy Fedden who said that the Pegasus/Mercury was unsuitable for twinning, and he was an engineer who didn't drive the train. In fact, he has been described as the highest paid engineer in Britain.

The Vulture engine, it turns out, was a success in that it was instrumental in the development of British jet engines. The test rig for development and testing of centrifugal compressors was driven by just such an engine.
 
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Although I'm no engineer it looks similar to trying to turn the Kestrel into the Vulture and the Daimler Benz coupled engines and it looks as if Alfa Romeo and Piaggio were about as successful.

DB and Allison twinned V12s were just that - full V12 engines, attached to a new reduction gear (though the Allison W24 shared supercharger(s) for both V12 halfs); one V12 half was able to be run independently in the DB.
The Vulture was with cylinder banks set at 90 deg from each other, thus it was no 'two V12s coupled', the V12s have had usually 60 deg between the banks. The clinder spacing was greater than in the Kestrel/Peregrine, thus blocks from those engines won't go to the Vulture. That also needed new crankcase, crankshaft, reduction gear, pumps, blower, manifolds... - you know the drill.

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The Vulture engine, it turns out, was a success in that it was instrumental in the development of British jet engines. The test rig for development and testing of centrifugal compressors was driven by just such an engine.

Not just that. People from RR used it's supercharger parts when developing the mercurial 2-stage supercharger for the Merlin.
 
The Vulture was with cylinder banks set at 90 deg from each other, thus it was no 'two V12s coupled', the V12s have had usually 60 deg between the banks. The clinder spacing was greater than in the Kestrel/Peregrine, thus blocks from those engines won't go to the Vulture. That also needed new crankcase, crankshaft, reduction gear, pumps, blower, manifolds... - you know the drill.
Therefore the moral to the MSB might be that if they want to build a more powerful engine they might as well make it a clean sheet of paper design than mess about with existing engines.
 
DB and Allison twinned V12s were just that - full V12 engines, attached to a new reduction gear (though the Allison W24 shared supercharger(s) for both V12 halves); one V12 half was able to be run independently in the DB.

The Vulture was with cylinder banks set at 90 deg from each other, thus it was no 'two V12s coupled', the V12s have had usually 60 deg between the banks. The cylinder spacing was greater than in the Kestrel/Peregrine, thus blocks from those engines won't go to the Vulture. That also needed new crankcase, crankshaft, reduction gear, pumps, blower, manifolds... - you know the drill.
Points taken.

The point I was trying to make was that the Italian engines, the DB coupled engines and Vulture while (as you have pointed out) not exactly the same were all attempts to make a more powerful engine by using components of existing engines.
 
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Therefore the moral to the MSB might be that if they want to build a more powerful engine they might as well make it a clean sheet of paper design than mess about with existing engines.

Spoken like a true non-engineer, but not true. MSB, as a company with no experience in radial aero-engine design, would end up with a clean sheet of paper. Radial engines were all based on some aspect of original radial engines from the past, from Cosmos Jupiter to Lawrance J-1. Do you know of an Australian engineer who could design such an engine, and remain in Australia until it was time to do so?

Points taken.
The point I was trying to make was that the Italian engines, the DB coupled engines and Vulture while not exactly the same (as you have pointed out) were all attempts to make a more powerful engine by using components of existing engines.

Engines have been made in this fashion, with eminent success, but also with additional engineering, not necessarily foreseen. The American radial twin-rows were such, to which were added the solutions to torsional vibrations by means of dynamic balancers.
 
Spoken like a true non-engineer, but not true. MSB, as a company with no experience in radial aero-engine design, would end up with a clean sheet of paper. Radial engines were all based on some aspect of original radial engines from the past, from Cosmos Jupiter to Lawrance J-1. Do you know of an Australian engineer who could design such an engine, and remain in Australia until it was time to do so?

Engines have been made in this fashion, with eminent success, but also with additional engineering, not necessarily foreseen. The American radial twin-rows were such, to which were added the solutions to torsional vibrations by means of dynamic balancers.
Insultingly put, but true.

However, you haven't read my thread. In my timeline the MSB had been trying to design an engine since 1924. First at the RAAF Experimental Station and then at the design office it sent up after the Experimental Station was closed. Furthermore it had been building engines under licence since the middle of the 1920s. This engine was going to be their first one that was good enough to put into production after several failures in the same way that Wackett had several failures before he got it right designing aircraft in Australia.
 
Insultingly put, but true.

However, you haven't read my thread.

Sorry. I don't write tone very well. I meant for it to sound whimsical. I have read the thread, but I suppose I tend to sail over the unbelievable bits, like the Australian aero-engine industry without sufficient customers, or engineers. I think there were about 9 Austalian aircraft engineers in the '30s, and Wackett was the one who stayed in Australia. W.S Shackleton was one who went to England and worked at Beardmore. He wasn't very keen. And you know, you spend imaginary government money as though it existed, when, at times, it was very tight.
 
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Engines have been made in this fashion, with eminent success, but also with additional engineering, not necessarily foreseen. The American radial twin-rows were such, to which were added the solutions to torsional vibrations by means of dynamic balancers.

Pratt & Whitney were not followers of the 'just add cylinders' engineering practice - neither R-2800 nor R-4350 were using cylinders of previous engines. We also have a thing where R-2800C series (mid/late 1944) could not be using any part from R-2800A (1939-41). The R-1830 used all-new cylinders vs. prevous P&W radials.
Wright have had severe reliability problems with R-3350 while following that practice, invoking plenty of changes to the design, while using up further resources and time - kinda shows that each engine must be actually designed, not just cobbled-together piece of machinery.

Apologies to NOMISYRRUC for thread derail :)
 
Pratt & Whitney were not followers of the 'just add cylinders' engineering practice - neither R-2800 nor R-4350 were using cylinders of previous engines. We also have a thing where R-2800C series (mid/late 1944) could not be using any part from R-2800A (1939-41). The R-1830 used all-new cylinders vs. prevous P&W radials.
Wright have had severe reliability problems with R-3350 while following that practice, invoking plenty of changes to the design, while using up further resources and time - kinda shows that each engine must be actually designed, not just cobbled-together piece of machinery.

Apologies to NOMISYRRUC for thread derail :)

You mean additional engineering.
 
Sorry. I don't write tone very well. I meant for it to sound whimsical. I have read the thread, but I suppose I tend to sail over the unbelievable bits, like the Australian aero-engine industry without sufficient customers, or engineers. I think there were about 9 Austalian aircraft engineers in the '30s, and Wackett was the one who stayed in Australia. W.S Shackleton was one who went to England and worked at Beardmore. He wasn't very keen. And you know, you spend imaginary government money as though it existed, when, at times, it was very tight.
I'll tactfully not comment on the first few sentences as we'll only wind each other up.

Re not having an aero engine industry even the countries that were established in the field by the middle 1920s started from nothing or adapting engines built for other purposes. I suspect that you know far more about the state of the British aero industry in August 1914 than I do. I know it had the benefit of a World War, but look at the progress it had made between then and the middle of the 1920s.

Re the Government money. All I was doing was having Australia spend the same proportion of its wealth on defence as the UK was. The UK was spending less than 3% of its national income on defence until the middle of the 1930s. I wrote the thread so that the personnel per capita of the Australian Defence Force was the same per capita as the British Armed forces of the era. (There is potential for better prepared Canada, New Zealand and South Africa threads based upon them spending the same proportion of their wealth as the UK too).

It was heavily skewed towards the RAN and RAAF, which I thought was justifiable because Australia maintained a very small regular army in peacetime but a large volunteer reserve army. I didn't do a post on the Australian Army because as usual I became hooked on new threads first and because I'd spent all the available money on the RAN and RAAF.

In the case of the RAAF I thought that up to 1934 I hadn't been that excessive. The IIRC 15 squadrons (including 12 CAF) wasn't that much. It's about comparable with Belgium and the Netherlands. Where I think that I went overboard was the expansion schemes after 1934. Though, even then it matched what the RAF was doing per capita. I was going to finish the RAAF of with a post called "Mobilisation" about the RAAF from September 1939 to December 1941. That was partially because I started to spend time on other treads, but also extrapolating what I had done so far produced a "telephone number" air force that was far larger than the maximum wartime strength of the OTL RAAF. To maintain it they would have had to cut back the wartime expansion of the Australian Army considerably. However, if they had an air force that large the Japanese would not have got so far and as a result they wouldn't need an army of 15-odd divisions.
 
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