Which country designed the best engines for WWII?

[Dash119]

No, Lockheed had their own proprietary design for an engine for the L-133, the L-1000. Interestingly it included an afterburner, which was really ahead of the times. It never proceeded any further than this mock-up;

Photo Credit: Sturmvogel 66

 

[Dash119]

Also, I believe it was Nathan Price at Lockheed rather than Kelly Johnson who was the driving force behind the L-1000. The L-133 was designed to incorporate the L-1000, not the other way around.

 

[pbehn]

And I thought Metrovick was Russian! Very educational.

For me what is interesting is how the same names keep cropping up all over the place especially Griffith, Hives, Hooker and Wilde. I was trained as a metallurgist and he was behind much of the things I was trained in and worked in up to retirement, but his work also involved development of the jet engine and he is also the reason why engine tuners, even now polish conrods.

 

[wuzak]

Axial compressors as an "idea" may date to before WW I for industrial uses (steel mills?) but practical (real world) efficiency was never great in the early years.

Griffith's paper of 1926 described using aerodynamic principles to design axial compressors. So they certainly existed prior to that, but weren't very efficient.

 

[pbehn]

Some interesting background here SAGE Journals: Your gateway to world-class research journals

 

[Reluctant Poster]

You would think that, but for various reasons some types couldn't run, or didn't run very well on one engine.

Insurance companies don't think twins are safer.
Wrong Worry in Twins Versus Singles
I was told the Canadian bush pilot theory was that a single was safer than a twin. Engine failures occur most often under maximum stress which is during take off. Two engines double your chances of failure.

 

[SaparotRob]

Insurance companies don't think twins are safer.
Wrong Worry in Twins Versus Singles
I was told the Canadian bush pilot theory was that a single was safer than a twin. Engine failures occur most often under maximum stress which is during take off. Two engines double your chances of failure.

It seems counter intuitive but those guys should know.

 

[Reluctant Poster]

Axial compressors as an "idea" may date to before WW I for industrial uses (steel mills?) but practical (real world) efficiency was never great in the early years.

For a jet engine (or turbo prop/shaft ) engine to work the compressor needs to use less power than the turbine section makes. Some of the early industrial engines could barely run (or didn't run) let alone provide extra power.

What was secret (or tried to be kept secret) was how to get all the stages in the axial flow compressor to play nicely together. If one stage stalls or misbehaves the entire assembly is useless. Figuring out which stage is the culprit and why was the hard part.

Aircraft oriented people tend to think that the gas turbine was invented specifically for flight. It was not. The first successful gas turbine was industrial and it had an axial compressor. It was in operation for 63 years.
https://www.asme.org/wwwasmeorg/med...story/landmarks/135-neuchatel-gas-turbine.pdf
The Swiss were the real pioneers of gas turbines and turbo chargers, in particular Brown Boveri.
https://library.e.abb.com/public/0d9d64cb85414b68890bb45bf805ca8e/bbc_mitteilungen_1941_e_08-09.pdf
BBC started making axial compressors in 1927. The Velox boilers were an intermediate step to the gas turbine.

 

[pbehn]

Aircraft oriented people tend to think that the gas turbine was invented specifically for flight. It was not. The first successful gas turbine was industrial and it had an axial compressor. It was in operation for 63 years.
https://www.asme.org/wwwasmeorg/media/resourcefiles/aboutasme/who we are/engineering history/landmarks/135-neuchatel-gas-turbine.pdf
The Swiss were the real pioneers of gas turbines and turbo chargers, in particular Brown Boveri.
https://library.e.abb.com/public/0d9d64cb85414b68890bb45bf805ca8e/bbc_mitteilungen_1941_e_08-09.pdf
BBC started making axial compressors in 1927. The Velox boilers were an intermediate step to the gas turbine.

It had a long gestation...… In 1900 Brown, Boveri and Co and The Parsons Foreign Patents Co entered into a contract for the sale and manufacture of the well-known Parsons' steam turbine in the following countries: France, Germany, Russia, Switzerland and Italy.[5] Charles Algernon Parsons - Graces Guide

 

[eljefe]

It seems counter intuitive but those guys should know.

We dealt with similar issues at NASA, in determining how much redundancy a system should have.

Two of anything is not safer if you need both of them to get by. It's less safe, since it's more likely one of two will fail than one of one. You have twice the chance of having at least one failure.

Safety is determined by how many you need to get by. If you can easily take off and land on one engine, then two engines are safer than one. But in reality, short field performance is very severely compromised on one engine, to the point where you may have power to spare to take off on two engines, and not enough power to continue the takeoff with only one.

Same thing with triples. If you can easily take off with two engines, then triples are safer than singles or twins (what are the odds that two of three engines will fail on the same take off run?) But if performance is "iffy" on two engines, then your triple is more dangerous than either a single or a twin...since you have 1 or 2 "extra" chances for an engine to fail.

This sort of thing is why Space Shuttle has 5 general purpose computers. Let's say a computation is critical for safe ascent. One computer might fail, so you need at least two. Great. Now, what happens if one computer says thrust must be set to 98% and the other one says thrust must be set to 92%? Which one is correct, and which one is failed?

Ok, now you have three computers, and a scheme where 2 of 3 must agree on the result. 92, 92, 98...ah, that one is failed. We can continue the ascent with GPCs 1 and 3, we'll shut #2 down.

What happens when all three disagree? Recall that the Shuttle was supposed to be able to abort a mission safely with 2 redundant items failed (which is why it had 3 of a lot of things). Well, that could be a software failure, so we need a computer running a completely different program designed by a different team...the Backup Flight Software is loaded in GPC 5, so shut down GPC's 1, 2, and 3, and bring up 5...etc.

 

[fastmongrel]

Interesting but not sure I would use the Space Shuttle as an example when talking about reliability and redundancy.

 

[pbehn]

It seems counter intuitive but those guys should know.

There are twins and twins. A Hornet could take off land and perform an air display on one engine, at the other end of the scale there were types like the Manchester Wellington and Hampden. A Manchester with full load fell like a stone on one engine, if it jettisoned its bombs it struggled to maintain altitude. It was a night bomber and UK was blacked out so at night you cant just "put it down", it took between 30 seconds and a minute for the crew to bail out. On one engine the pilot couldnt bail out when the rest had gone, as soon as he let go of the controls the plane would spin, so he had to kill the other engine, hope it stayed straight and level then get out. To go through all that your engine needs to fail at a convenient, high altitude. In a Hampden, the navigator couldnt start to get out until the pilot had gone, how does that work?

 

[SaparotRob]

There are twins and twins. A Hornet could take off land and perform an air display on one engine, at the other end of the scale there were types like the Manchester Wellington and Hampden. A Manchester with full load fell like a stone on one engine, if it jettisoned its bombs it struggled to maintain altitude. It was a night bomber and UK was blacked out so at night you cant just "put it down", it took between 30 seconds and a minute for the crew to bail out. On one engine the pilot couldnt bail out when the rest had gone, as soon as he let go of the controls the plane would spin, so he had to kill the other engine, hope it stayed straight and level then get out. To go through all that your engine needs to fail at a convenient, high altitude. In a Hampden, the navigator couldnt start to get out until the pilot had gone, how does that work?

Badly?

 

[pbehn]

Badly?

Even worse when the pilot is dead at the controls.

 

[wrenchedmyspanner]

No, Lockheed had their own proprietary design for an engine for the L-133, the L-1000. Interestingly it included an afterburner, which was really ahead of the times. It never proceeded any further than this mock-up;

View attachment 613294
Photo Credit: Sturmvogel 66

It's my understanding that this design (also known as the J37) never really went anywhere. Neither did the turboprop derived from it, the T35. A few working prototypes were produced but the J37 at least, was determined to be under powered.

 

[azador1606]

I'm a bit ignorant on this subject.

But I guess Merlin was amazing, Griffon was good, so England has a good reputation.

For the USA, Pratt Whitney?

Junkers Jumo for Germany?

Jets - well the question was "best design in ww2", so we can only give 1st prize to Germany and second prize to the UK with Japan and USA bringing up the rear by a long way.

Inlines - Jumo 213 by the end, but the UK had the Merlin at the beginning and the Griffon and the Sabre later. The US can't really be credited with the "design" of the Packhard Merlins and the Allison is not on par with the DBs, Jumos or Merlins. The Jumo diesels, fuel injection and pressure-cooling, and other German innovations in my opinion from a "design" rather than simply performance point of view hands this category to Germany also, with the Brits once again in second place. USA and Russia fight it out for third place and the Japanese a distance 5th.

Radials - Oh this is close. While the BMW 801 is outstanding, it is really all on its own (but did they need more?). Design, what's the big differences in the radials? Japans Sakae is a worthy contender to the TwinWasp and the Kinsei really developed well but Japan failed really with the big engines - so I think the R-2800 stands out here. I'll score the radial for the USA, with Britain, Japan and the Soviets all vying for second spot. Design: USA 5 Japan 4 England 3 Germany 2 Russia 3

This may seem to give the overall "best" to the UK which is competitive in all categories without winning any of them! However since jets were THE technology of aircraft engines to come AFTER the war, and since we are talking design rather than performance or impact - then the real winner of this question is: Germany

 

[Shortround6]

Problem with the Allison was the supercharger.
By the end of the war some Allisons in P-40 trainers were going almost 1000 hours before overhaul.

Not saying that makes the Allison "Best" but sometimes trick or cool design features don't mean much in the real world.

BTW the US wasn't as far behind with jets by the end of the war as many believe. GE may have gotten the basic concept from the the British by early 1945 the GE engines were making more power than the British ones.
The Westinghouse J30 wasn't too bad for it's time either.

Everybody's jet engines sucked as far as reliability goes in 1944-47 so trick design features don't mean much if you are killing pilots or rapidly raising the membership of the caterpillar club.

 

[GrauGeist]

Interesting but not sure I would use the Space Shuttle as an example when talking about reliability and redundancy.

After 135 missions and a total of 21,030 orbits of the planet over the course of 30 years, I'd say the loss of two out of a fleet of five is not a bad track record.

 

[pbehn]

After 135 missions and a total of 21,030 orbits of the planet over the course of 30 years, I'd say the loss of two out of a fleet of five is not a bad track record.

I first read about it in the late 1960s, think of what cars were on the road then.

 

[MiTasol]

After 135 missions and a total of 21,030 orbits of the planet over the course of 30 years, I'd say the loss of two out of a fleet of five is not a bad track record.

I would say an average crash rate of once every 54 flights was not very good at all.

Last time I needed to look up the in-flight shut down record on the CF6-80C series engines (in the mid 1990's) it was once in every 185,000 operating hours.

Based on a average flight time of say four hours, (many 767s were on one hour flights and some of the ERs were doing over 18 hours daily on sectors exceeding 10 hours), that gives one failure for every 740,000 flights.

To me that is a somewhat better track record although admittedly in a far less hazardous flight regime.