Video:

http://vimeo.com/16117810


"A test stand video of the Pratt & Whitney 4360 Wasp engine introduced in 1944. Basically, the engine was 28-cylinder four-row air cooled radial engine. Each row of pistons was slightly offset from the previous, forming a semi-helical arrangement to facilitate efficient airflow cooling of the successive rows of cylinders, with the spiraled cylinder setup inspiring the engine's "corncob" nickname. A mechanical supercharger geared at 6.374:1 ratio to engine speed provided forced induction, while the propeller was geared at 0.375:1 so that the tips did not reach inefficient supersonic speeds. Initially, it developed 3,000 horsepower, later models gave 3,500 horsepower.
The 4360 powered the B-50, successor to the B-29 and later the B-36, to name a few. And although reliable in flight, the Wasp Major was maintenance-intensive. Improper starting technique could foul all 56 spark plugs, which would require hours to clean or replace. As with most piston aircraft engines of the era, the time between overhauls of the Wasp Major was about 600 hours when used in commercial service."

And they were a joy to hear flying in low and loud!

We were still flying super constellations and AD Skyraiders while I was in the Navy. They actually used the Skyraiders in Viet Nam. I think that was the last of them. Our hot rod pilots would take those Skyraiders out and really wring them out. Then our air frame mechanics would have to go over them and tighten up all the rivets.

If it is at all possible for a human being to be passionately in love with an engine, the R-4360 is the unrequited love of my life.
Thanks for posting.

From the first time I saw one, on display in a museum, it could have been surrounded by nude women, offering fine dark ale and rib-eye steak, and I wouldn't have noticed them.

[This message has been edited by williegoat (edited 06-11-2012).]

My lawnmower.

quote Originally posted by dratts: We were still flying super constellations and AD Skyraiders while I was in the Navy. They actually used the Skyraiders in Viet Nam. I think that was the last of them. Our hot rod pilots would take those Skyraiders out and really wring them out. Then our air frame mechanics would have to go over them and tighten up all the rivets.

They were still teaching 'some' recips when I was on instructor duty at NAS Millington in '73-74 on the Southside. We had several ADR1s in the classrooms down the way from us, still had the old hangar with the cutaway R engines, right next to a hangar with a ch53A model in it. Those ADRs could DRINK!!

quote Originally posted by maryjane: They were still teaching 'some' recips when I was on instructor duty at NAS Millington in '73-74 on the Southside. We had several ADR1s in the classrooms down the way from us, still had the old hangar with the cutaway R engines, right next to a hangar with a ch53A model in it. Those ADRs could DRINK!!

I "did" AD school in 1991 after Desert Storm. The AD school had one of these things (wasp) on display in the wood building s where we removed/replaced an Jet engine from an F4 Phantom for training.

The south of Millington. Today sadly, the AD school has moved on. Millington today is missing many of her old buildings.

quote Originally posted by williegoat: If it is at all possible for a human being to be passionately in love with an engine, the R-4360 is the unrequited love of my life. Thanks for posting. From the first time I saw one, on display in a museum, it could have been surrounded by nude women, offering fine dark ale and rib-eye steak, and I wouldn't have noticed them.

Despite being around air bases, and seeing a lot of planes, I never realized just how awesome some of these are. Awesome engines, I want one as well.

No idea what I would do with it, except show it off, but I want one lol.

Brad

That engine would look good in a fiero
Hey I can dream

Previously posted on PFF ... This isn't from a 4360 "Corncob," but from an engine of similar vintage. It's a brand new 3-liter cylinder for a Wright 3350 radial:

[This message has been edited by Marvin McInnis (edited 06-12-2012).]

Its art!

I couldn't afford the avgas to run it for a minute!

Wow, that's like 4 of these stacked and then some!





My buddy's plane

Love the sound of those engines.

Reminds me of "Dreadnought" from the Reno Air Races that I had the pleasure of going to back in 1983--85--and 87.

quote Originally posted by Toddster: I couldn't afford the avgas to run it for a minute!

... and the oil consumption is measured in gallons per hour. The spec limit for the R-4360 engine was about 6.6 gph at cruise power (0.015 lb/hp/hr), although 1 to 2 gph was more typical.

I've always been amazed at the level of sophistication of these old radials.

This thing was designed and built in the 1930's and 1940's, with slide rules and lots of pens and paper. No computers, CAD, or calculators.

When it matured it produced 3,800 hp from 43.6 liters. Compare that to the 5-6 liter automotive engines of the era making about 100 hp.

I think these (and most radials) are actually very fuel efficient especially compared with the first jet engines but their maintenance costs and frequent overhauls made them expensive to operate.

quote Originally posted by masospaghetti: When it matured it produced 3,800 hp from 43.6 liters. Compare that to the 5-6 liter automotive engines of the era making about 100 hp.

Make that 4360 cubic inches ... or about 72 liters. That's a whopping 152 cubic inches (2.5 liters) per cylinder. But 3800 hp from 4360 cubic inches isn't all that remarkable ... only about 0.87 hp per cubic inch.

By contrast, some versions of the turbo-compound^* Wright R-3350 engine produced 3800 takeoff hp from only 3350 cubic inches ... about 1.13 hp per cubic inch. The R-3350s were also notoriously fragile.


^*Not only was the Wright R-3350 supercharged, but it also had an exhaust turbine mechanically coupled to the crankshaft to recover heat energy that would otherwise have been lost, thus increasing both power output and fuel efficiency.

quote I think these (and most radials) are actually very fuel efficient especially compared with the first jet engines but their maintenance costs and frequent overhauls made them expensive to operate.

The BSFC (brake specific fuel consumption, expressed in pounds of fuel consumed per horsepower-hour ... lower is better) of the R-4360 was about 0.43 lbs/hp-hr, which is still very good by modern standards. But the BSFC of the R-3350 was only 0.40 lbs/hp-hr, making it the most fuel-efficient gasoline aircraft engine ever manufactured ... even 70 years after it first appeared.

No gas turbine ever made even approaches the fuel efficiency of a good piston engine. Even an efficient turboprop has a BSFC of ~0.80 lbs/hp-hr. Turbines were quickly adopted for aircraft use for several reasons:

- Very high power output available in a comparatively small and light package.
- Turbines have far fewer moving parts ... none of them reciprocating ... and are vastly more reliable. Most of the big radials required a complete overhaul every 400 to 600 hours of operation in airline service ... if they didn't blow themselves up first. The R-3350, in particular, was a notorious flamethrower.
- Propeller efficiency drops dramatically at high aircraft speeds, due primarily to the prop tips going supersonic. Turbines don't need a propeller.
- The fuel efficiency of turbines increases significantly at high altitudes, where the aerodynamic drag on the aircraft is lowest.

Despite their complexity, big radials are still quite a bit cheaper to maintain than turbines ... primarily because of the expensive exotic metals required in turbines due to high operating temperatures in the combustors, turbine wheels, and exhaust nozzles.

quote For something really wild, check this out: ... It looks like a radial but the crankshaft is stationary, and the cylinders spin...!!

That's so WW-I. The Fokker Triplane (of Red Baron fame) and the Sopwith Camel (of Snoopy fame) both had such rotary engines. The gyroscopic "flywheel effect" of all that rotating mass caused huge problems with aircraft maneuverability in aerial combat. Pitch up => the aircraft yawed left or right, depending upon the direction of engine rotation; pitch down => it yawed the other way. Similarly, a yaw or turn was always accompanied by an uncommanded pitch up or down. Not really what you want in a gun platform.

An interesting related note from this source:

"When a French pilot, Roland Garros, bolted steel deflectors to his propeller, which permitted him to fire a machine gun through it, the airplane became an offensive weapon."

Was this the origin of the French word ricochet?

[This message has been edited by Marvin McInnis (edited 06-13-2012).]