Thread: Pratt & Whitney R-4360-20 First Start

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There's just something about round engines!! Below, you will find a great 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, thetime between overhauls of the Wasp Major was about 600 hours when used in commercial service.

Turn the speakers all the way up. The sound will most likely clear out the cat, your wife and any other extemporaneous people not accustomed to military sounds and the glorious roar of a Pratt & Whitney "round" engine. As the Warbird people used to say, "Jets are for kids."

Pratt & Whitney R-4360-20 first start on Vimeo

Awesome, I saw one just last week in a Super Corsair at the Museum of Flight in Seattle. They also have one on a stand, It's cutaway so you can see the innards.

Thanks for the post, Roger – I’ve always been in awe of the radials and love the “whump-whump-whump” sound they produce. Can you imagine the sheet of paper this design started on? The brain-power to take a concept and turn it into an engine is well – amazing! I’ve worked with a lot of engineers in my life and had the very distinct pleasure of once meeting Zora Arkus-Duntov and listening to him talk about how one horsepower per cubic inch was only the starting point. How incredibly visionary these people were and we continue to reap the benefits of their enthusiasm. George Mead was truly a pioneer in aviation engine design.

Great Post!!
Glenn

If ever in the area of Dayton Ohio---take a day or whatever time you can spare and do the air force museum there---free parking and entry-------and look at the stuff that they built for ww2 in a short time----and now its all about i pads/phones---------

One that really surprised me recently was that the British De Havilland Mosquito was almost entirely made of wood. It was very fast, and had an extended range with it's payload of fuel, and light weight. Quite an airplane!

A somewhat familiar sound, spent almost a couple thousand hours behind similar models...............................and have the hearing loss and tinitis to prove it.

Originally Posted by Bob Parmenter

A somewhat familiar sound, spent almost a couple thousand hours behind similar models...............................and have the hearing loss and tinitis to prove it.

Oh how many times did I stand in front of a R1820 running at full power listening for an elusive miss.... Too many times to count, and like Bob I have the tinnitis to show for it.

I can't hear you cause of this ringing in my ears-----------

Besides the typical normal sounds around the airport in my life since 1961----- Caravelles were very loud at about 45* angle to the nose of aircraft--of course as they taxied into the gates, it was like a gatling sound gun on a swivel cause they did in the whole area as they made at that time a 180-270 turn into parking

And then there was the time at Indy that Keeling wasn't there yet so I poured the Sperex for the burnout for the left wheel, stepped over the nose of dragster to pour right side, did the sign to Ramsey to do the burn out and Wiebe was in the other lane at same time---I was BETWEEN them ---ears rang like a constant siren for two days------