Development Potential of Bristol Mercury and Pegasus engines

This is a question related to the better prepared Australia thread. At present I'm having the Australian Munitions Supply Board build the Bristol Mercury and Pegasus under licence in its ordnance factories from about 1933.

AFAIK both were developed up to 1,000hp. However, it would fit what I have in mind much better if they could have been developed to produce 1,200hp in 1940. Is that possible?
 
Bristol did try a Fuel-Injected version, the Draco. However, it provided little improved performance for the expenditure.
(The problem is that 1000hp is about as far as you can push a single-row 9 cylinder radial engine)
 
An alternative is to built the Bristol Hercules under licence instead of the Wasp and Twin Wasp. IOTL the first Australian Wasp was produced in January 1939 (after ordering the Wirraway in January 1937) and the first Twin Wasp in November 1941 (after the July 1939 decision to build the Beaufort in Australia).

IIRC IOTL the Short Golden Hind airliner with four 1,400hp Hercules and the Saro Lerwick with two 1,500hp Hercules was in service in the middle of 1939-ish.

With a POD of 1936 is production of the Hercules in Australia from early 1938 feasible?
 
An alternative is to built the Bristol Hercules under licence instead of the Wasp and Twin Wasp. IOTL the first Australian Wasp was produced in January 1939 (after ordering the Wirraway in January 1937) and the first Twin Wasp in November 1941 (after the July 1939 decision to build the Beaufort in Australia).

IIRC IOTL the Short Golden Hind airliner with four 1,400hp Hercules and the Saro Lerwick with two 1,500hp Hercules was in service in the middle of 1939-ish.

With a POD of 1936 is production of the Hercules in Australia from early 1938 feasible?
The Prototype was first run in 1936 and entered service in 1939, historically.
Its probably possible? I think you should ask Astrodragon for his opinion.
 
The Prototype was first run in 1936 and entered service in 1939, historically.
Its probably possible? I think you should ask Astrodragon for his opinion.

Its possible, the time frame works. The problem is going to be the Bristol board, who'd have to be persuaded to allow a not-yet-developed engine to be let loose in Australia. JustLeo can probably give you a better likelihood of this (even if it is bad for his blood pressure :)
 
This is a question related to the better prepared Australia thread. At present I'm having the Australian Munitions Supply Board build the Bristol Mercury and Pegasus under licence in its ordnance factories from about 1933.

AFAIK both were developed up to 1,000hp. However, it would fit what I have in mind much better if they could have been developed to produce 1,200hp in 1940. Is that possible?

Unless Bristol tries to attach a kind of system that would've been spraying the anti-detonant mixture in the supercharger (similar to what was done in with German MW 50 system, or the system installed on many R-2800s for example) or carb, the power will remain firmly at 1000 HP, and a bit less for the Mercury. Or/and up the RPM, that will represent another set of challenges.
The Pegasus was a small engine for a radial (28.7L) while turning modest RPM (2600) and being light at ~500 kg for much increase of boost/RPM/power.

added: one funky idea might've been that Bristol and De Havilland join the forces and make a V12 air cooled engine, using cylinders and rest of usable parts from Pegasus. 1300 HP in 1938?
 
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Unless Bristol tries to attach a kind of system that would've been spraying the anti-detonant mixture in the supercharger (similar to what was done in with German MW 50 system, or the system installed on many R-2800s for example) or carb, the power will remain firmly at 1000 HP, and a bit less for the Mercury. Or/and up the RPM, that will represent another set of challenges.
The Pegasus was a small engine for a radial (28.7L) while turning modest RPM (2600) and being light at ~500 kg for much increase of boost/RPM/power.

added: one funky idea might've been that Bristol and De Havilland join the forces and make a V12 air cooled engine, using cylinders and rest of usable parts from Pegasus. 1300 HP in 1938?
Thanks, but I've decided that the Australian Munition Supply Board, which in my TTL builds Napier Lion and Bristol Pegasus engines under licence uses the experience it gained from then to design an engine in the 1,000 to 1,500hp class.
 
An alternative is to built the Bristol Hercules under licence instead of the Wasp and Twin Wasp. IOTL the first Australian Wasp was produced in January 1939 (after ordering the Wirraway in January 1937) and the first Twin Wasp in November 1941 (after the July 1939 decision to build the Beaufort in Australia).

IIRC IOTL the Short Golden Hind airliner with four 1,400hp Hercules and the Saro Lerwick with two 1,500hp Hercules was in service in the middle of 1939-ish.

With a POD of 1936 is production of the Hercules in Australia from early 1938 feasible?

As to the early manufacture of Hercules, they didn't look very reliable nor did they create gobs of power early on. It was discovered that the Lerwick couldn't fly on one engine, and the Short couldn't fly on two, or three when one is ablaze. The Hercules required some manufacturing expertise to be developed, using specialized machine tools, with specialized modifications, as well as newly developed alloys from your local alloy steel shops in Sheffield and Birmingham, England. The Herc wasn't something the Aussies would lust after before the Hercules VI.

I find it difficult to embrace the concept of building an original engine to fill a gap before another engine takes its place, since building engines is very hard, and takes time and gobs of money. Severe misgivings aside, I do suggest the name MSB Bungeroo for this engine. Have you given any thought to what kind of engine? I would have thought the R-1830 fills enough of the gap to preclude other options.
 
As to the early manufacture of Hercules, they didn't look very reliable nor did they create gobs of power early on. It was discovered that the Lerwick couldn't fly on one engine, and the Short couldn't fly on two, or three when one is ablaze. The Hercules required some manufacturing expertise to be developed, using specialized machine tools, with specialized modifications, as well as newly developed alloys from your local alloy steel shops in Sheffield and Birmingham, England. The Herc wasn't something the Aussies would lust after before the Hercules VI.

That Saro Lerwick could not be flown on single engine was probably not due to Hercules being of low power, but due to Lerwick being a big, draggy and heavy aircraft - bigger than B-26 or Ju 88, or twice as big as Bf 110. Short Stirling shared the problem - it was the biggest A/C between the 3 British heavies.
Granted, sudden manufacture and introduction of a sleeve valve twin-row radial engine would've been quite a task for the country without the experience with that.
 
That Saro Lerwick could not be flown on single engine was probably not due to Hercules being of low power, but due to Lerwick being a big, draggy and heavy aircraft

It takes two to tango. The Lerwick was a heavy pig, terrible in the water and terrible in the air, and the engines were weak and not reliable. Which is to blame? The guys who built it, or the guys who accepted it into service and ordered dead men to fly it? Your choice.
 
It takes two to tango. The Lerwick was a heavy pig, terrible in the water and terrible in the air, and the engines were weak and not reliable. Which is to blame? The guys who built it, or the guys who accepted it into service and ordered dead men to fly it? Your choice.

The guys that built it were confident that two 1375 HP engines can reliably power a monoplane flying boat of 845 sq ft wing, loaded weight of 28400 lbs, and max t.o. weight of 33000 lbs. The 2-engined A/C should be able to at least glide well with one engine out, and people at Saro either did not take the single engine capability in the account, or their calculations were wrong. Perhaps they lied to the costumer? Either way, their blame can't be denied.
People that bough it either believed Saro's calculations, or (and?) failed to properly test the prototype and cancel it once it was discovered that 1-engine operation is a major safety hazard. So the people that bought it were guilty, too. There is no 'manufacturer or costumer', it is 'manufacturer and costumer' in this case.
As it was the case with Blackburn Botha, or Ba.88 Lince.

Saying that 'engines were weak' in case of Lerwick is a majorization - 1375 HP in 1939-40 was no small feat. I'd also love to see a real comparison in reliablility of the engines in that time frame so we could deduce that early Hercules was really a dog.
 
Saying that 'engines were weak' in case of Lerwick is a majorization - 1375 HP in 1939-40 was no small feat. I'd also love to see a real comparison in reliablility of the engines in that time frame so we could deduce that early Hercules was really a dog.

We could add the Taurus engines of this time frame as well. It never really outgrew its reputation, but it entered service before maturity in greater numbers. Production techniques and metallurgy did wonders.
 
I find it difficult to embrace the concept of building an original engine to fill a gap before another engine takes its place, since building engines is very hard, and takes time and gobs of money. Severe misgivings aside, I do suggest the name MSB Bungeroo for this engine. Have you given any thought to what kind of engine? I would have thought the R-1830 fills enough of the gap to preclude other options.
ITTL the MSB had been developing its own engines since 1924, first via the Engine Section of the RAAF Experimental Station at Randwick and then directly after the Engine Section becomes the design department of its aero engine factory. None of the engines designed between 1924 and 1934 went into production because they were worse than the British engines that they could build under licence. The Bungeroo would have been begun in 1934. I hoped that would have been enough time to put a 1,000 hp Bungeroo into production in 1939, followed by a 1,200hp version in 1940 and the final version producing 1,500hp in 1942.

As to what kind of engine I wanted it to be a single-row, air-cooled radial using poppet valves. I.e. a development of the Pegasus with more cylinders or larger ones. I used poppet valves rather than sleeve valves because the MSB engineers were being more conservative. By basing the Bungeroo on the Pegasus the MSB could use the same production tooling to make it.

I did think of Wackett or the MSB getting a licence on the Twin Wasp earlier, but ITTL I want the Australians to develop their own engines or built more British engines under licence.
 
I'm not going to change it, but with hindsight (which would make it an Alternative Alternative History) the chain of events should have been along these lines:
  1. In the 1920s the RAAF still buys De Havilland Hounds, Supermarine Seagulls and Supermarine Southamptons fitted with Napier Lion engines built by the MSB;
  2. In the early 1930s the RAAF buys the De Havilland Hound Mk II, Supermarine Walrus and Supermarine Stranraer, but instead of these types being fitted with Bristol Pegasus engines built by the MSB, they have Rolls Royce Buzzard engines built by the MSB;
  3. The advanced trainer that Wackett designs instead of the taking a licence out on the Harvard is powered by a Buzzard engine. The alternative to that is that the Miles Master with Buzzard or Kestrel engines was built in Australia instead of the Harvard;
  4. In 1936 when the RAAF orders 300 Hampdens to be built by the MSB instead of 50 Bolingbrokes to be built by Bristol it specifies that they have Rolls Royce Merlin engines built by the MSB instead of Pegasus engines. When it orders the Short Sunderland from the MSB to replace the Stranraer the RAAF specifies that these aircraft have Merlin engines instead of the Pegasus.
That sets Australia up to build the Hurricane or Spitfire instead of the armed version of the Wirraway and the Buffalo and/or for Wackett to design single and twin Merlin powered aircraft in the second half of the 1930s. It also gives De Havilland Australia the opportunity to offer the RAAF a fast unarmed light-bomber cum long-range fighter made of wood and powered by 2 Merlin engines.
 
The guys that built it were confident that two 1375 HP engines can reliably power a monoplane flying boat of 845 sq ft wing, loaded weight of 28400 lbs, and max t.o. weight of 33000 lbs. The 2-engined A/C should be able to at least glide well with one engine out, and people at Saro either did not take the single engine capability in the account, or their calculations were wrong. Perhaps they lied to the costumer? Either way, their blame can't be denied.
People that bough it either believed Saro's calculations, or (and?) failed to properly test the prototype and cancel it once it was discovered that 1-engine operation is a major safety hazard. So the people that bought it were guilty, too. There is no 'manufacturer or costumer', it is 'manufacturer and costumer' in this case.
As it was the case with Blackburn Botha, or Ba.88 Lince.

Saying that 'engines were weak' in case of Lerwick is a majorization - 1375 HP in 1939-40 was no small feat. I'd also love to see a real comparison in reliablility of the engines in that time frame so we could deduce that early Hercules was really a dog.
I think part of the problem with the Botha and Lerwick was that they were among the types that the Air Ministry ordered into production "off the drawing board" from 1936 instead of the previous policy which was to order several competitive prototypes, test them at the A&AEE or MAEE and then put the best one or two designs into production. It did this to save time and AFAIK in the knowledge that some of them would fail or at least be severely delayed.

In the case of Specification R.1/36 the best design was tendered by Supermarine. However, the firm was too busy with the Spitfire and the heavy bomber designed to meet Spec. B.12/36 so it went to Saunders Roe by default.
 
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The Poles were setting themselves up to licence build Hercules in 1940. It may well be that they had bigger and better engineering capabilities than Australia though?
 
WI Bristol of Australia developed twin-row versions of Mercury and Pegasus engines? Use as many original parts as possible and try to limit new-design parts to (3 bearing) crankshaft and crankcase.
At 3,000 cubic inches and maybe 1,200 horsepower, BA could sell a few Twin Mercury engines even if they competed directly with the larger single-row radial engines.
OTOH a Twin Pegasus engine producing 1,800 to 2,000 horsepower should prove valuable for long-range transports and bombers. What kinds of airplanes could the RAAF power with 2,000 hp Twin Pegasus engines?

Post war, Twin Pegasus engines could be over-hauled and power airliners for many years.
This compares favourably with OTL Port WW2 Trans Canada Airlines which struggled to maintain Merlin engines (on Canadair-built DC-4 North Stars) but flew many millions of hours on low-maintence radials.

OTL Saro Lerwick looked like it lacked a large enough rudder to fly straight on one engine. Dragging that tall a fuselage through the air side-ways would create enormous amounts of drag.
 
WI Bristol of Australia developed twin-row versions of Mercury and Pegasus engines? Use as many original parts as possible and try to limit new-design parts to (3 bearing) crankshaft and crankcase.
At 3,000 cubic inches and maybe 1,200 horsepower, BA could sell a few Twin Mercury engines even if they competed directly with the larger single-row radial engines.
OTOH a Twin Pegasus engine producing 1,800 to 2,000 horsepower should prove valuable for long-range transports and bombers. What kinds of airplanes could the RAAF power with 2,000 hp Twin Pegasus engines?

Post war, Twin Pegasus engines could be over-hauled and power airliners for many years.
This compares favourably with OTL Port WW2 Trans Canada Airlines which struggled to maintain Merlin engines (on Canadair-built DC-4 North Stars) but flew many millions of hours on low-maintence radials.

OTL Saro Lerwick looked like it lacked a large enough rudder to fly straight on one engine. Dragging that tall a fuselage through the air side-ways would create enormous amounts of drag.
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.
 
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