Radials vs Inlines in the PTO?

Invader26 · **Joined:** Wed Aug 11, 2010 7:56 am **Posts:** 843

Of course the Royal Navy carriers operated Seafires and Fireflies in the Pacific as well as Corsairs/Hellcats/Avengers...

dirtysidedown430 · **Joined:** Sat Apr 11, 2015 12:36 pm **Posts:** 336

Let's not forget that there are inline aircooled engines.

Dave Hadfield · **Joined:** Sun Sep 17, 2006 10:31 pm **Posts:** 1672

Yes, the US Navy wanted to move away from liquid cooled aero engines in the years after WWI. They had an active role in pressuring corporations to merge, buy-out, and develop engines they wanted.

Check out this http://www.enginehistory.org/air-cooled ... rs_2.shtml

Don't forget, the Liberty had a TBO of as low as 80 hours in the years before Allison developed the steel-backed bearing. (from Whitney: Vees for Victory)

The development of the air-cooled cylinder for higher-powered engines was a magnificent engineering accomplishment. It was the culmination of the best knowledge of the times in metallurgy, thermodynamics, machining, fuel technology, and engineering.

Dave

Scott Rose · **Posted:** Mon May 25, 2015 7:51 am

dirtysidedown430 wrote:

Let's not forget that there are inline aircooled engines.

True, but AFAIK they never really gained in popularity or power output like the radials. If there are big air-cooled inlines please point them out! I'd love to learn about them.

marine air · **Posted:** Mon May 25, 2015 9:59 am

V-12s have a lot more torque than the radials. Comparing the Korean War service of the Corsair and P-51, the P-51 had the highest combat losses. If you compare each, the engine of the Corsair has a smaller cross section and be harder to hit with ground fire than a V-12. Also with a Corsair if the bullets don't hit the pilot, engine, or fuel, it'll still be in the fight. With a V-12 you have a longer area for the bullets to hit and take it out. Particularly the location of the Mustangs radiator.

JohnB · **Posted:** Mon May 25, 2015 10:14 am

marine air wrote:

Comparing the Korean War service of the Corsair and P-51, the P-51 had the highest combat losses.

That may be, but you just can't compare total losses...or even loss ratio per sortie. To make your case you'd need to know the cause of each loss. Unless it's directly engine related, you're run the risk of comparing apples to oranges.

marine air wrote:

If you compare each, the engine of the Corsair has a smaller cross section and be harder to hit with ground fire than a V-12.

by "cross section" do you meant frontal area? If so, I disagree. If you're talking side area, then you're correct.

marine air wrote:

Also with a Corsair if the bullets don't hit the pilot, engine, or fuel, it'll still be in the fight. With a V-12 you have a longer area for the bullets to hit and take it out. Particularly the location of the Mustangs radiator.

Well, yes. The Mustang or any water cooled aircraft has a radiator. More systems gives the enemy another thing to possibly hit. Or to put it simply, another thing to go wrong.

But don't be too damning of in-lines...some mighty fine planes in the war had them: Spitfires, Hurricanes, Bf-109s, P-38s, P-38-39-40s...to name a few.

dirtysidedown430 · **Joined:** Sat Apr 11, 2015 12:36 pm **Posts:** 336

The largest inline air cooled eng that I know of off hand would be the Argus the Germans put in the fi 156 Storch, upside down V8. Wonder where they came up with upside down engs, always wondered if they had hyd locks on them. The Brits did not like radials because of that flat front witch caused all that drag. But the extra air scope added more drag on the liquid cooled, which of course added another system to fail and on after start up you had to get them flying pretty quick or they would over heat on the ground. Then with north american 51 they came with that air intake which produced thrust thus did away with the drag thing. So I would lean to side of radels in the end easy to take care off just pull the prop through ready to go. And i know what its like to keep an airplane going in the sun rain and mud, with hardy any tools or help. But they both got the job done one way or another.

Dave Hadfield · **Joined:** Sun Sep 17, 2006 10:31 pm **Posts:** 1672

Ranger made an inverted V-12. http://en.wikipedia.org/wiki/Ranger_V-770 that produced over 500 hp.

Not generally viewed as a success.

Dave

dirtysidedown430 · **Joined:** Sat Apr 11, 2015 12:36 pm **Posts:** 336

Well shut my mouth. Ths for info got on that one.

Ramjet · **Joined:** Sun May 31, 2015 4:03 am **Posts:** 11

Didn't the radials need to be warmed up and warmed down, before and after full throttle to prevent the crankcase from warping?? Were they more fragile than the inlines? Or did the inlines need to be treated with the same respect?
Perhaps the warping story might be specific to just one or two models.....

DH82EH · **Posted:** Tue Jun 02, 2015 4:46 pm

Look who holds the world piston speed record.

Radial (Rare Bear)

I'm sure those folks will refer to the phrase that "you can fly a radial farther than you can ship a Merlin"

Andy

John Dupre · **Posted:** Sun Jun 14, 2015 7:07 pm

A liquid cooled V type engine can give you all the power you want instantly. It will usually only do it once. The AVG found that they had to retrain all of its' former Navy and Marine pilots to treat the throttles on their P-40s more gently in order to prevent engine failures on the Allison engines from occurring on the next flight. A number of training crashes attributed to engine failure were found to have happened after a former carrier pilot had slammed the throttle back and forth too quickly. Radial engines are built with looser tolerances in the hot parts of the engine (which is one reason they leak oil so much) since there is no coolant to keep metal expansion in check.

Nathan · **Posted:** Sun Jun 14, 2015 10:57 pm

In all honesty the real heavy players regarding inline in the pacific were the P-39, P-40, P-38. As has been stated the USNavy standardized on radial engines. Don't know why, just know what I read and remember never seeing an inline engine aircraft on a US Carrier(minus Curtiss SO3C).

IMHO, both theaters used an equal amount of both types of powerplants.

JohnB · **Posted:** Mon Jun 15, 2015 8:24 am

Nathan wrote:

Don't know why, just know what I read and remember never seeing an inline engine aircraft on a US Carrier(minus Curtiss SO3C).

See posts 10,11,12, 13 for some well-reasoned speculation.

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Radials vs Inlines in the PTO?

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