Question about engines in WWII-era A/C

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Question about engines in WWII-era A/C

Joined: November 19th, 2006, 8:23 pm

March 11th, 2012, 2:04 pm #1

I'm sure everyone but me knows this one, show I'll show some ignorance here. It seems like all/most carrier-based aircraft had radial engines and all/most land-based aircraft had inline engines. This seems true of both U.S. and Japanese aircraft. Just wondered why.
Mike Todd

yeah, all except the part about him being presumed dead.
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Joined: March 2nd, 2005, 3:52 pm

March 11th, 2012, 2:27 pm #2

At least in the USN, water cooled engines were just not done. Also, air cooled engines are lighter, and less prone to damage from bullets, flak, etc. One small hit in a cooling line and you're going to land very soon. And if you're 200 miles from the carrier, that might be problematic. Air cooled radials can take a lot more punishment and still keep running.
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Joined: February 28th, 2005, 5:27 am

March 11th, 2012, 2:35 pm #3

I'm sure everyone but me knows this one, show I'll show some ignorance here. It seems like all/most carrier-based aircraft had radial engines and all/most land-based aircraft had inline engines. This seems true of both U.S. and Japanese aircraft. Just wondered why.
Mike Todd

yeah, all except the part about him being presumed dead.
Japan had very few operational planes with inline engines (Ki-61?) and Germany didn't have an operational carrier, but the Stuka was being modified for it and has an inline engine.

USAAC/F had inline and radial - whatever worked best.

Really your idea does fit the US Navy, about the US not having inline engines on carriers. Sort of true - radial engines could still function with damage, whereas inlines required a more fragile cooling system and glycol/prestone - an extra item that had to be stocked on the carrier.

I do believe the Curtiss Seamew used an inline engine, but that was a floatplane tender aircraft not on carriers.
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Joined: January 27th, 2004, 1:10 am

March 11th, 2012, 3:54 pm #4

Wasn't the Seamew fitted with the Ranger, which is an air-cooled engine? n/t
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Joined: August 9th, 2009, 2:56 pm

March 11th, 2012, 3:54 pm #5

Japan had very few operational planes with inline engines (Ki-61?) and Germany didn't have an operational carrier, but the Stuka was being modified for it and has an inline engine.

USAAC/F had inline and radial - whatever worked best.

Really your idea does fit the US Navy, about the US not having inline engines on carriers. Sort of true - radial engines could still function with damage, whereas inlines required a more fragile cooling system and glycol/prestone - an extra item that had to be stocked on the carrier.

I do believe the Curtiss Seamew used an inline engine, but that was a floatplane tender aircraft not on carriers.
The radial engines had less parts lacking a cooling system and was therefore easier to care for aboard ship. I think that at the time the decision was made (probably prewar) the thinking was that generally speaking a liquid cooled engine would deliver more power per pound of weight and would allow the A/C to be streamlined thus reducing drag so it was the better choice over land. This was of course before the R-2800 appeared which was the first A/C engine to deliver more than 1 hp. per 1 lb. of engine weight and could be tightly cowled. The radial was less complicated and more reliable and could take much more damage so it was the natural choice over water. Japan is of course is an Island nation and the empire they sought to build spread out of endless miles of ocean so this would explain why most of there A/C were radials. the Ki 61 is an exception but then it's a Japanese copy of the Bf 109.
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Joined: February 27th, 2005, 3:49 am

March 11th, 2012, 3:58 pm #6

I'm sure everyone but me knows this one, show I'll show some ignorance here. It seems like all/most carrier-based aircraft had radial engines and all/most land-based aircraft had inline engines. This seems true of both U.S. and Japanese aircraft. Just wondered why.
Mike Todd

yeah, all except the part about him being presumed dead.
Basically, as has been said here, inlines are more delicate and heavier than radials. The flip side is that inlines are better aerodynamically.

The Japanese had three aircraft with inlines, the Tony, Judy and Seiran. Due to a lack of experience with inlines and lack of materials for making seals they did not do well operationally, though it is worth noting that both Tonys and Judys were outfitted with radials later on. A slightly slower plane in the air is better than a fast one in the shop!

In Europe, the very strong trend was to inlines. Longer experience with them and less over water flying I guess. The only radials were the Fw190 and some Russian aircraft such as Lavochkins.

The US Army Air Corps seems to have gone with almost exclusively inlines for fighters and radials for bombers. I am going to guess that lightness for bombers to allow more load and to give fighters more speed. Funnily enough, they did not want superchargers on their inlines which is why the P40 and P39 were sluggish at high altitudes.

The reasons for any particular engine being used is partly tradition in the service in question, availability and in some cases, performance!

Joking aside, you can make all the general rules you like and there are exceptions to all. The 190, Sturmovik, P47, La5/7, etc are all exceptions to conventional wisdom regarding engine choice. Yet all were extremely successful.

None of this gives you a definitive answer but I am sure you are getting that there are no hard and fast rules and that such decisions were made on a case by case basis, often not for purely aerodynamic reasons.

I hope that helps,

Chris
Last edited by ccowx on March 11th, 2012, 4:02 pm, edited 1 time in total.
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Joined: February 27th, 2005, 3:49 am

March 11th, 2012, 4:00 pm #7

The radial engines had less parts lacking a cooling system and was therefore easier to care for aboard ship. I think that at the time the decision was made (probably prewar) the thinking was that generally speaking a liquid cooled engine would deliver more power per pound of weight and would allow the A/C to be streamlined thus reducing drag so it was the better choice over land. This was of course before the R-2800 appeared which was the first A/C engine to deliver more than 1 hp. per 1 lb. of engine weight and could be tightly cowled. The radial was less complicated and more reliable and could take much more damage so it was the natural choice over water. Japan is of course is an Island nation and the empire they sought to build spread out of endless miles of ocean so this would explain why most of there A/C were radials. the Ki 61 is an exception but then it's a Japanese copy of the Bf 109.
Not sure if you meant that the Ki61 is a copy, or just the engine. The engine most definitely was a licensed copy of a BD601. The airframe is an original design.

Chris
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Joined: March 2nd, 2005, 8:00 pm

March 11th, 2012, 5:03 pm #8

lkj

So a friend says: "cheer up things could be worse; so I cheered up and sure as hell Things Got Worse!
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Joined: October 11th, 2008, 5:33 am

March 11th, 2012, 5:11 pm #9

I'm sure everyone but me knows this one, show I'll show some ignorance here. It seems like all/most carrier-based aircraft had radial engines and all/most land-based aircraft had inline engines. This seems true of both U.S. and Japanese aircraft. Just wondered why.
Mike Todd

yeah, all except the part about him being presumed dead.
don't have the additional parts required for liquid cooled engines to be carried onboard, along with the space requirements for radiators, coolant, hoses, tubes, fittings, etc.

After decades of study, it has become obvious that Murphy was an optimist...
Last edited by jimmbbo on March 11th, 2012, 5:13 pm, edited 1 time in total.
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Joined: June 30th, 2004, 2:35 am

March 11th, 2012, 5:38 pm #10

Not sure if you meant that the Ki61 is a copy, or just the engine. The engine most definitely was a licensed copy of a BD601. The airframe is an original design.

Chris
would have been good for Germany to copy.

The concentration of wealth means the proliferation of misery.

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