Shortround6
Major General
I was wondering when Stanley left Bristol and went to America
Which country designed the best engines for WWII?
- Thread starter Soundbreaker Welch?
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I was wondering when Stanley left Bristol and went to America
Admiral Beez
Captain
Those are radial, not rotary engines. The last rotary engine used in an aircraft was the Soviet Cheryomukhin TsAGI 1-EA, flown in 1932.
Admiral Beez
Captain
Bristol's sleeve valve radials were a true demonstration of complexity, just look at all the geared wheels in the Hercules below. But yes, the later Centaurus is one of the best radials, too bad it wasn't ready for the Typhoon and Tempest early on, and an early Sea Fury would have been something in WW2.
Get the Centaurus into play earlier and the FAA can have its Hawker Tornado.
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PWR4360-59B
Senior Airman
- 379
- May 27, 2008
Those sleeve valve Bristol Centaurus engines are very nice. Too bad there are so few of them around when so many where made in the day.
Yes,
but for some reason the Brits decided to have CCW rotation on their engines which was odd, and out of step with just about everyone else.
Deleted member 68059
Staff Sergeant
- 1,058
- Dec 28, 2015
Yes,
but for some reason the Brits decided to have CCW rotation on their engines which was odd, and out of step with just about everyone else.
Actually its extremely common and often had to be changed within engine model lines anyway, as for twin engine applications is very common to
want a CCW rotating engine on the left, and a CW rotating engine on the right (or visa versa, doesnt matter).
For example there are CW and CCW Merlins.... makes no difference to the physics of engine dynamics, you just have to make sure all the pumps and
acessories still turn in the correct direction afterwards - so many detail changes are needed !
Griffon turns opposite to Merlin, Merlins did CW and CCW... etc etc etc. There is no accepted standard for this, and no inherent advantage
either way.
I assumed it was easier to fit an idler gear in the prop reduction gear case as they did in the Merlin 130 series: Rather than re-engineer an opposite turning engine of the same type (though they did this for the Meteor application).
Every aero piston engine I have seen turns CW. I had understood probably mistakenly, that the UK engine manufacturers made a decision mid-way through WW2 to standardise all UK manufactured aircraft engines to be CCW. (?)
wuzak
Captain
The Allison was designed to rotate both ways, but they had to put an idler gear in the accessory drive train of the left-hand engines in order for them to rotate in their normal direction. This included the supercharger.
As discussed in another thread, the Peregrines in the Whirlwind prototype (as it first flew) were handed - I'm not sure if it was the complete engine or in a manner similar to Allison.
As discussed in another thread, the Peregrines in the Whirlwind prototype (as it first flew) were handed - I'm not sure if it was the complete engine or in a manner similar to Allison.
wuzak
Captain
The Griffon changed rotation compared to the Merlin because either the FAA requested it (Griffon was originally to be for naval aircraft) for safety reasons or to be consistent with other British manufacturers - or just Bristol, who co-owned the Rotol propeller company with Rolls-Royce.
The first one seems to be unlikely, since the Griffon cause a swing to the right and towards the island.
In my opinion, the Pratt & Whitney R-2800 was the best engine of the war. Radial engines were a lot more robust than inline engines and didn't need cooling. The list of aircraft on which the Double Wasp was successfully installed is as long as your arm.
However, I am pragmatic enough to know this is like arguing Ford vs. Chevy or white wine vs. red wine. I am glad the Allies had both of those engines.
Just read an article about the Lancaster and Lincoln using the Merlin.
Seems these planes flew well on two engines.
The Merlins offered more HP per cuin and got a bit better fuel mileage.
How do you compare them to the B17, B24 and B29?
As for robustness of engine both seemed survivable when hit.
The accessories to keep them flying was problematic.
Radial has large oil tanks and coolers...
Liquid cooled had radiators did not seem to have the same flaming conditions when hit.
Head on or rear you could hit a radials cylinder and know it out of commission.
Some survived a loss of a cylinder most got locked up.
Did not see that as a problem with liquid cool as a bullet would tend to glance off the block.
IMHO there was no particular survivability advantage between the engines.
fastmongrel
1st Sergeant
I remember reading somewhere that in the Pacific and SEAsia the F4U was a lot more vulnerable to light AA than the F6F because of the Oil cooler being in a more vulnerable place. In the European theatre the Typhoon doesnt seem to have been any more vulnerable than the P47.
Corsair had same issue in Korea and with small arms fire.
Interesting the P-51 if hit in the coolant area had about 15 minutes to get out of the area.
Did not catch fire as easily but then again when the coolant was used up the engine quit.
P-47 had a huge oil tank and cooler and lines going to the turbo.
Both Corsair and Mustang had near identical loss rate.
Though the Mustang could stay on station longer than Corsair.
Just had better range.
Both were very effective at CAS and GS as they destroyed lot of war material and troops.
It was a very wicked war encountering more 40 mm AA than in WW2.
fubar57
General
"The F-51 Mustang found a new lease of life during the Korean War (by 1950 the P-51 Mustang had been redesignated as the F-51 in line with the new classifications used by the USAF). In the five years between the end of the Second World War and the outbreak of that war in 1950, the majority of American fighter units had converted to new jet fighters. Their F-51Ds had either been left at their bases, or handed to the National Guard. In 1950 they were suddenly needed again. The new jet aircraft were fast, but had low endurance. They did not make good fighter bombers over an active battlefield.
The F-51 was also not an ideal aircraft to use in this role – the liquid cooled Merlin engines were vulnerable to ground fire, but the USAAF had already scrapped its P-47 Thunderbolts, which would have been more suited to the role (the US Navy used the Corsair for the same duties over Korea, where its radial engine made it rather more survivable). The F-51 performed a valuable role in Korea, where the rocket armed aircraft were able to inflict significant damage on North Korean ground forces, despite suffering heavy losses themselves, mostly from ground fire"
The F-51 was also not an ideal aircraft to use in this role – the liquid cooled Merlin engines were vulnerable to ground fire, but the USAAF had already scrapped its P-47 Thunderbolts, which would have been more suited to the role (the US Navy used the Corsair for the same duties over Korea, where its radial engine made it rather more survivable). The F-51 performed a valuable role in Korea, where the rocket armed aircraft were able to inflict significant damage on North Korean ground forces, despite suffering heavy losses themselves, mostly from ground fire"
swampyankee
Chief Master Sergeant
- 3,954
- Jun 25, 2013
Horsepower per pound installed weight is a much more important criterion than per cubic inch. While the specification weights neither air- nor liquid-cooled engines include the cooling system (it may include intercoolers, but that's likely it), the radiator of a liquid-cooled engine and the associated plumbing is a significant weight, probably several hundred pounds for a high power engine, such as the Merlin. The radiator will probably also need about as much surface area as the finning on a radial, so, except for some very special cases, will probably cause about as much drag as a properly designed air-cooled installation. (Negative cooling drag is possible on air-cooled engines as well as liquid-cooled ones; in neither case is it trivial, but it's easier with radiators, but ejector exhaust works with either)
I suspect that much of the damage tolerance of radials vs in-lines is more associated with the airframe's design than with that of the engine proper. Most WW2-era fighter-fighter combat will have damage coming from behind, mostly directed at the fuselage. Some aircraft, for example the Mustang, place their radiators in the rear fuselage, which is where they're more likely to be hit than a forward-mounted radiator, as on the P-40 or the liquid-cooled FW190 variants, or wing-mounted radiators, as on the Spitfire. Air-cooled engines don't have radiators, but they do have oil coolers, but these are smaller than the radiators (they're rejecting less heat at higher temperatures) and and tend to be placed relatively far forward. During ground attack, most of the fire will be coming from below, and aimed for the visual center of the aircraft, which means that it will tend to impact around the wing-fuselage juncture. I'd like to see some data about where damaging hits occurred in both cases, but I suspect these data aren't there.
I suspect that much of the damage tolerance of radials vs in-lines is more associated with the airframe's design than with that of the engine proper. Most WW2-era fighter-fighter combat will have damage coming from behind, mostly directed at the fuselage. Some aircraft, for example the Mustang, place their radiators in the rear fuselage, which is where they're more likely to be hit than a forward-mounted radiator, as on the P-40 or the liquid-cooled FW190 variants, or wing-mounted radiators, as on the Spitfire. Air-cooled engines don't have radiators, but they do have oil coolers, but these are smaller than the radiators (they're rejecting less heat at higher temperatures) and and tend to be placed relatively far forward. During ground attack, most of the fire will be coming from below, and aimed for the visual center of the aircraft, which means that it will tend to impact around the wing-fuselage juncture. I'd like to see some data about where damaging hits occurred in both cases, but I suspect these data aren't there.
wuzak
Captain
Oil temperatures were usually lower than coolant temperatures in WW2 aircraft.
Air-cooled engines also reject more heat through the oil cooler than did liquid-cooled engines, as a proportion of the overall heat rejected.
Air-cooled engines also reject more heat through the oil cooler than did liquid-cooled engines, as a proportion of the overall heat rejected.
I had a great uncle who looked out of his top turret of his B-25 and saw a piston pumping up and down on the starboard engine with no visible means of support. That engine held together long enough to clear out of Simpson Harbor and get it feathered. The fact that he told me about it 60 years later gives some credence to radial engines being able to take punishment. Anecdotal proof, I know.
Liquid cooled engines will always be inherently more problematic than an air cooled radial. Nobody ever had to bail out of a P-47 because his Pratt & Whitney ran out of air due to a leak, due to combat or mechanical. Coolant storage and exchange is just one more thing to go wrong. I think there was some experience behind the line pilots used to say (paraphrased), "If you want to impress your girl, fly a P-51. If you want to go home to your girl, fly a P-47."
Lastly, I believe glycol is flammable.
