With 4,360 cubic inches and 3,500 hp in standard tune, the Pratt & Whitney Wasp Major was the biggest U.S radial at the close of the piston era. Let’s hear it run.
As you’ve no doubt noticed, here at Mac’s Motor City Garage we’re fascinated with radial engines. They’re much like any other piston powerplant, but with some remarkable differences. We’ve featured a number of radials, but now it’s time to share a look at the most powerful U.S radial to see regular use, the Pratt & Whitney R-4360, known to all as the Wasp Major.
Developed too late for combat duty in World War II, the Wasp Major flew in a number of aircraft in the immediate postwar era, including the Boeing 377 Stratocruiser, the C-119 Flying Boxcar, and the B-36 Peacemaker, the USA’s largest bomber. One more notable application: Eight of them powered Howard Hughes’ Hercules H4 flying boat, the Spruce Goose. Close to 19,000 engines were manufactured between 1944 and 1955.
With four staggered rows of seven cylinders, each one displacing 152 cubic inches, the Wasp Major boasted a total displacement of 4,360 cubic inches (71.5 liters) but weighed just 3,500 lbs. Standard models employed a centrifugal supercharger and developed up to 3,500 hp at 60 inches of manifold pressure, drinking 2,500 lbs of aviation gasoline per hour. There was also a twin-turbocharged version, the R-4360 VDT, that made 4,300 hp.
Fiendishly complicated and prone to running hot at the rear cylinders, the R-4360 required delicate care and maintenance. B-36 flight engineers monitored the Sperry Engine Analyzer, an on-board oscilloscope with a set of rotary switches that allowed them to keep tabs on the four engines and make sure all 112 cylinders were playing along. Fortunately, the engine we’re featuring here is still in sound running order after 75 years. Once the oil and fuel clear out of the cylinders, the Wasp Major makes a glorious noise. Video below.
No home should be without one! Every home needs a fan to circulate air. Love the chrome “headers”!
Thanks for sharing. Not likely that I’d see or hear one sing in person.
Good to hear that engine again. I suspect this was a hot start as it caught so easily. On initial cold start the prop would turn 10-20 times before the engine could reluctantly fire, and then it would take a minute more for all cylinders to cooperate. On initial warm up the engine would emit plumes of blue smoke.
I note a real propeller was attached. Usually on off-airplane maintenance a “club” is used. A club is a shortened prop with the same weight as the real propeller. Clubs don’t generate thrust, so the engine, and test stand, has less tendency to take flight. I also noticed the blades were pitched, meaning they were generating thrust. This is probably why the engine was left at idle.
Curiously, it looks like the engine was run in a proper aviation engine test cell. These enclosures mitigate noise (and potential explosions). Surprised any still exist. When Pratt & Whitney operated its World War II factory in Kansas City manufacturing the R-2800C, they had dozens for the first start of engines coming off the assembly line. I was told many of these test cells, after the war, were purchased by Trans World Airlines and installed at their overhaul base at Fairfax Airport, Kansas City, Kansas. Most were damaged or destroyed in the 1951 flood, causing the airline to move it’s base north to Mid-Continent Airport, now Kansas City International.
I’m old enough to remember the Convair B-36Js flying over KCK between Carswell AFB, Texas, and Offut AFB, Nebraska. The Peacemakers were on cruise-descent to Offut when they passed my backyard. The flight engineers never could get those six engines synchronized.
I seem to remember this engine was also used for a small run of F4U’ corsairs.
This was the Corsair Race 74’s engine for Reno in 2011. It made metal on a test flight and locked up after landing. Another 4360 was used to get it to Reno and race.
My uncle was a flight engineer on the B-36 — in fact, one of the two used to film Strategic Air Command with Jimmy Stuart — and he spoke of syncing the engines. Said it was a bit of work, but the FEs did it just fine.
I salute the people who care for these engines and keep them alive. It can’t be easy. A large crane is required just to move them around.
I was a parts vendor at the Rolls-Royce Owner’s Club national meet at the Homestead resort in Virginia, in the early 1990s I think. One of the participants had mounted a 12 cylinder Rolls-Royce built Merlin aircraft engine for a British Spitfire fighter onto a substantial open trailer pulled behind his large truck. The Merlin had a full size 4-bladed propeller.
In an open grassy area behind the hotel the trailer and truck were chained down using about a dozen large truck rear axle shafts driven all the way into the ground until only the outer flanges were visible. This was required to anchor everything down, and keep the trailer and truck from being dragged rearward upon firing the Merlin up.
Even as we stood several hundred feet away from the trailer, the noise from that huge engine was deafening, and I could see the whole truck & trailer straining against the anchor chains.
And that experience was “only” a V-12, not a radial 28 cylinder behemoth like the Wasp Major! I have a hard time comprehending just how loud that must have been in person.
A cool story that has nothing to do with these engines.
Small correction: A B-36 had 6 (six) of these engines, and 168 cylinders
In 1960-3 I was stationed at Yokata AB near Tokyo.. There were two wings of B 50s which had R 4360 engine and were modified B 29s stationed there at that time. One was the 56th weather Wing operating WB 50s the other was a KB 50 (whose designation slips my 86 year old mind) refueling wing which in addition to the four 4350s had two J47 turbojets from B47s. The WBs occupied the ramp near Base ops only a hundred yards or so from our barracks.. Lou d they were, we were often privileged to be awoken by engine run ups at 0 dark 30. I managed three flights on WBs during my 2 1/2years there due to fixing some radio problems (I was ground radio) I later tore down and reassembled a 4360 as part of the Aircrft Maintenance Officer coursework.
I worked on these on C119’s in 1969,197. Awesome engine. Most amazing part to me was that they were held on the wing by just four not really very big bolts. Nothing sounds cooler than a big radial coming to life.