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Sabre engine ability to absorb damage

ACResearcher

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The Merlin-powered P-51's are often spoken of as elegant, high-speed, long-range aircraft that turn into an instant brick if hit in the wrong place with but a single bullet. While this is clearly a bit of hyperbole, it is true in comparison with some of the radial's ability to absorb damage. I think here of the eternal R-2800 radial engine.

In the process of doing a bit of studying about ground-attack aircraft in the mid- and late-war period I became curious about the Saber's ability to absorb damage in its role as a ground-attack aircraft.

Does anyone have any specific and verifiable information on this topic??

AlanG
 

Zoo Tycoon

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I understand the problem to be linked to the pressurised water cooling, whereby a small hole looses the coolant in a very rapid manner, followed by over heat. Any water cooled engine will be susceptible to this with more highly pressurised exhibiting greater sensitivity.

Radial engines are much better because of the air cooling which eliminates this single point failure. I remember talking to an engineer that was told by a customer that his Bristol Centurous had developed a curious knock. Upon investigation an entire piston had broken up, the free conrod had punch through the casing and the oil leakage was stemmed by the thick coating of dead bugs on the cylinders.
 

gruff

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The engine could make any plane a death trap; unreliable, needing to be started on the first try or its compartment would fill with gas vapors, and vulnerable to enemy fire.
Captain Baker of Martin Baker lost his life due to "late early teething problems" and Pierre Clostermann (The Big Show) of 122 Wing was still begging for Centaurus engines at the end of the war.
There was overall much more than vulnerability at stake. Does anybody know if it saw any civilian use after the War?
 

Calum Douglas

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I dont have statistical evidence on battle damage sustained by the Sabre equipped aircraft in operation vis-a-vis survivability. I would think that the risks are about equal
to any water cooled engine. Because of this, I would suggest that a study of the airframe would be more important than the engine itself, as the hardiness of the plane`s powerplant operation to small arms fire will relate more to if the coolant system has any armour plate, rather than the engine itself.

Sadly as archives everywhere are closed, its not currently possible to obtain more data.
 

riggerrob

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In comparison, the Soviet Sturmovik had its radiator inside an armoured box in the fuselage. The intake was on top of the engine cowling. Air flowe3d downwards through the radiator, then exited under the belly. Sturmoviks still suffered heavy loses, but most were due to the fierce, low altitude fighting on the Russian Front.
 

riggerrob

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Few Sabre-engined Typhoons or Tempests served much after the Second World War. The Sea Fury continued on for a few more years, but it was powered by the superlative Bristol Centaurus radial engine. But piston-engined fighters were soon eclipsed by jets.
Bristol Centurus also powered a few transports like the Bristol Freighter.
 

red admiral

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I understand the problem to be linked to the pressurised water cooling, whereby a small hole looses the coolant in a very rapid manner, followed by over heat. Any water cooled engine will be susceptible to this with more highly pressurised exhibiting greater sensitivity.

There are some interesting outliers in the massive dataset from WW2 etc. E.g. I saw a story of a Firefly in Korea that took a 37mm to the chin radiator and then flew back to the carrier.
 

DWG

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It seems to me that the difference comes down to redundancy, a air-cooled radial engine had inherently multiply redundant cooling because it's based on airflow over the cylinders, whereas water-cooled inlines had single points of failure if you punched a big-enough hole anywhere in the engine-radiator cooling circuit. OTOH if we were building a combat inline with today's design concepts we'd probably look to have a multiply redundant cooling system, so I don't think watercooled inlines are necessarily worse, we just built them that way.

And on the third hand, it's the Sabre, it's Napiers, and they never met a part they didn't think would be better off as three, or five, so simple over-complexity might make the Sabre uniquely vulnerable.
 

Mike Pryce

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I understand the problem to be linked to the pressurised water cooling, whereby a small hole looses the coolant in a very rapid manner, followed by over heat. Any water cooled engine will be susceptible to this with more highly pressurised exhibiting greater sensitivity.

There are some interesting outliers in the massive dataset from WW2 etc. E.g. I saw a story of a Firefly in Korea that took a 37mm to the chin radiator and then flew back to the carrier.
Took it on the chin and kept going!

Some politicians want us all to 'be more Firefly'.
 

F119Doctor

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One of the neat tricks possible with modern electronic fuel injection is the ability to turn off the fuel to a cylinder on every other power stroke, allowing the engine to air cool at a reduced power level when the liquid coolant is lost. Many current auto engines have this limp home capability. It would have been useful for the liquid cooled WW2 fighters.

I don’t know if this type of capability could have been accomplished with dual mechanical injection pumps at the time.
 

sienar

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It seems to me that the difference comes down to redundancy, a air-cooled radial engine had inherently multiply redundant cooling because it's based on airflow over the cylinders, whereas water-cooled inlines had single points of failure if you punched a big-enough hole anywhere in the engine-radiator cooling circuit. OTOH if we were building a combat inline with today's design concepts we'd probably look to have a multiply redundant cooling system, so I don't think watercooled inlines are necessarily worse, we just built them that way.

And on the third hand, it's the Sabre, it's Napiers, and they never met a part they didn't think would be better off as three, or five, so simple over-complexity might make the Sabre uniquely vulnerable.

Radials still have an oil cooler or two which is just as venerable as a radiator in most cases. There are a decent number of ww2 era inline equipped fighters with two radiators and the ability to shut off one of the circuits.
 
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