Photos and Videos...The Pratt and Whitney Double Wasp...

...after all the well deserved discussion of the Merlin engine...I thought I would post this thread highlighting America's contribution to World War Two fighter plane engine technology...the Pratt and Whitney Double Wasp...

...what the Merlin did with engineering finesse...the Double Wasp did with the theory...more is better...more cylinders...18...more cubic inches...2800...and more horsepower...2000...evolving to 2400 by war's end in the Corsair...

...the Double Wasp was an eighteen cylinder (two rows of nine each)...air cooled...supercharged...radial engine...the air cooling was an advantage...as a well placed hit anywhere in the cooling system of the water cooled Merlin...Allison...or German DB 605...was a death blow...there are stories of the Double Wasp getting a pilot back home with entire cylinders shot off of the engine...

...the higher horsepower versions used in the Corsair swung a 13 foot 4 inch propellor...to put that in perspective...that propellor stood up on a basketball court...would extend four inches above the top of the backboard on the goal...that propellor is the reason for the dip in the Corsair's wings...to keep the landing gear to a manageable length and weight...and still keep the propellor off the ground when taxiing...taking off...and landing...

...the Double Wasp was also used in many other applications...both during and after the war...

...CLICK ON THE PHOTOS for full size...





...below are three excellent videos of the Double Wasp in action in the F4U Corsair flown by the Marine Corps...the P-47 Thunderbolt flown by the US army Air Corps...and the F6F Hellcat flown by the US Navy...click on the photos...

I love the way the cross section of the cylinder and head reminds one that a Bomb goes off in the top it, 25 times a second :-)

Bill

edit:and its a great sounding engine :-)

https://www.youtube.com/watch?v=DVD7m9gqQ8M

Originated in the nice machine shop at 400 Main Street, East Hartford CT.

Retired Engineering VP Jack Connors wrote this. He was 80 when I visited him in 2003

https://www.google.com/url?sa=t&rct...c47d8oRrNV-k0xfcADmAfMw&bvm=bv.98717601,d.eXY

"Double Wasp" or "Twin Wasp" ?

I've seen both the term Double Wasp and Twin Wasp in relation to P&W radials. Which is the correct nomenclature, assuming they refer to the same R-2800 engine? Or, is a Twin Wasp something else entirely?

There's a cut-away of a PW R-2800 at the West Point Museum. It's connected to a small, slow, electric motor so all those parts can be seen in coordinated motion.

There is something almost beautiful about the cylinder head finning on a Double Wasp.

SouthBendModel34 said:

I've seen both the term Double Wasp and Twin Wasp in relation to P&W radials. Which is the correct nomenclature, assuming they refer to the same R-2800 engine? Or, is a Twin Wasp something else entirely?

There's a cut-away of a PW R-2800 at the West Point Museum. It's connected to a small, slow, electric motor so all those parts can be seen in coordinated motion.

Click to expand...

The Twin Wasp is a 14 cylinder 2 row radial of 1830 c.i.d. It is easier to keep track of these engines by their military designations, in these cases R1830 and R2800.
While P&W produced the R2800 in 2 factories they were also produced by Chevrolet, Nash-Kelvinator, and Ford. Ford produced over 54000 of these.

To be able to design an engine like the Wasp is something that boggles my mind. Seeing the cutaway and the myriad of fine parts that make up those engines is also mind boggling. Add to that the fact those engines were being produced in wartime, in huge numbers, in factories which previously had never made aviation engines. Imagine all the jigs and fixtures and special tooling that had to be made and kept up so those engine parts could be built and be within tolerance. It took an army of toolmakers to back up the production. Then, there were all sorts of machine tools used in the production. Some were specially built, some were basic like gang drills or turret lathes. Keeping all those machine tools working and being able to do their operations without breakdown or problems from wear kept another army of machine tool repair mechanics and machinists busy, I am sure. Imagine all the inspection that went on, not just dimensionally or by gauging, but to insure there was proper finish and no minute stress risers. Plants turning out cutting tools and measuring instruments like dial indicators and mikes were probably going full bore to support the production of those engines.

Component parts like magnetos kept one plant not too far from here in Sidney, NY running full bore- Scintilla. Shielded ignition wires, "cigarette holder" spark plugs, all had to be made somewhere in record numbers and tested and accepted. So did carburetors, starting motors, generators, and all sorts of fittings and fasteners. When an engine like the Wasp went together, a lot of the fasteners were safety or lock wired. Running the lock or safety wiring was another art, and a good mechanic could make it look like jewelry. So much fine work went into those engines. No CNC, no digital readout, no CAD to play with the design and see how things fit together.... no computer programs, no finite element stress analysis done by computer. It was all designed and built relying on human intelligence, engineering and mathematical analysis, testing of engines on dynamometers with instrumentation that had a gang of people taking readings and writing them down. The drawings for the Wasp engines were drawn by human beings on drawing tables, not by CAD. Prints of those drawings were run on blueprint machines by more human beings, who manually cut the print paper to size. No CAD and no large format printers. There were huge numbers of people kept busy making prints from "originals" or sepia prints done on a translucent film, and then there were more people who had to check that anyplace work was being done to make or inspect parts for the Wasp engines was working from the latest revision of the drawings. If a revision was issued to a drawing by engineering, it could require someone to take a roll of the drawings with the latest revision and get on a train to bring them to a subcontractor's shop or to a plant like Kelvinator or the auto makers out in Michigan. even making sure the latest revision of drawing was in the hands of the toolrooms or the shop floors could require people walking miles within the plants, opening "flat files" of drawings in each location, or getting drawings on and off "sticks".

Every aspect that I think of when I look at an engine like the Wasp boggles my mind. We take for granted that today's design is done using software, and people can play around with the design without erasing and re-drawing, and can transmit drawings electronically. We take for granted that very few jigs, fixtures, or individual production machines are needed, since CNC machining centers have seemingly unlimited capability. I'd like to think the toolmakers are still there, making the specialized tooling even in this CNC age.

The Wasp engines were a testament to the incredible genius of the engineers, and the skills and determination of legions of people who used their minds and bodies in ways that modern engineering and manufacturing does not require.

The Wasp, or any classic radial aircraft engine, is a thing of beauty. It was likely one of the zeniths of I/C engine design and production. Seeing this thread, I think of the old Pratt & Whitney logo- an eagle flying with "Pratt & Whitney- Dependable Engines". Seeing that logo on the cowling of a commercial jet airliner engine when I looked out the cabin window was reassuring. However, even though seeing the Pratt and Whitney logo on a jet aircraft was not the same feeling I get when I see the Wasp engine. The Wasp IS a real aircraft engine.

Joe your comment of a "real" aircraft engine reminded me of something about 30 years ago. I was living in Oklahoma and the job required some travel. I was at DFW and our plane was cleared for take off. As the pilot taxied inline with runway I could see on the parallel runway a DC3 of a little regional freight carrier. Beautiful!! Round engines, tail dragger and the pilot has his window open and cap crushed by the headphones looking like a B 17 pilot in a WWII movie. And I felt the same way, there's a REAL airplane!!

in these cases R1830 and R2800

Click to expand...

A version of the 1830 was the 2000. 5.75 X 5.5 instead of 5.5 square

billmac said:

There is something almost beautiful about the cylinder head finning on a Double Wasp.

Click to expand...

...almost delicate and elegant...isn't it?...

You are looking at the cast head. The later FORGED heads had milled fins, not nearly as elegant - they were still churning these out in the mid sixties when I started the apprenticeship

See forgings and Milled fin photos here:

https://www.google.com/url?sa=t&rct...HDVFKZp0MN9-MSOCHWaPg8A&bvm=bv.98717601,d.eXY

billmac said:

There is something almost beautiful about the cylinder head finning on a Double Wasp.

Click to expand...

Here is a link to an animation of a Wasp Major I posted in another thread
https://www.youtube.com/watch?v=Kr0AxAPeGiI

Regards,
Jim

Here is a link at Pratt & Whitney for their "Classic Engines"

Classic Engines

It says that they made 125,334 engines from 1939 - 1960

And,then think about those multiple row "corncob" engines!! A wonder the rear banks of those engines didn't overheat.

After flying the R-2800 for over 1000 hours during the Great War, (Vietnam), I can attest to the raw power and dependability of this great P&W engine. On my last combat mission, the right engine stopped by itself after clearing the runway at Danang. Once in the revetment, the crew chief opened the cowl and a cylinder and about ten gallons of oil fell out on the ramp. This from an engine that gave no indication of failure. Old times there are not forgotten. Regards, Clark

gwilson said:

And,then think about those multiple row "corncob" engines!! A wonder the rear banks of those engines didn't overheat.

Click to expand...

The P&W 4360

sealark37 said:

After flying the R-2800 for over 1000 hours during the Great War, (Vietnam), I can attest to the raw power and dependability of this great P&W engine. On my last combat mission, the right engine stopped by itself after clearing the runway at Danang. Once in the revetment, the crew chief opened the cowl and a cylinder and about ten gallons of oil fell out on the ramp. This from an engine that gave no indication of failure. Old times there are not forgotten. Regards, Clark

Click to expand...

...thank you for that personal account...and thank you for your service to our country...

When I started in Avionics the airline was still overhauling R2800s. The shop was a floor below ours and I would go down and study their innards.
Lovely!
Airline was flying DC-6"s and Convair's.
I was nosing around a Convair in for overhaul, noticed belly sheet metal was wrinkled.
Asked a sheet metal Mech about it.
"Oh this oe landed in a Cornfield, gear up. Both engines had stopped, deadsticked it in, gear up. Minor damage, no injuries, Pilots awarded instant "Hero" status.
THEN it was discovered they forgot to switch fuel tanks! Loss of hero status.
They jacked it up, changed the Props and flew it out of the Conrfield..
I would assume the Farmer made a record profit from that field's crop.

..here is a metal emblem on the cover of a beautiful 4360 sales catalog.

The five inch I-beams held well until we hung the 16 1/2 foot prop on it, twelve feet from the mounts.
Then they twisted like warm butter.

I can't imagine the two 1 1/4 inch bolts on top and the two 1 inch bolts on the bottom both holding the QEC (Quick Engine Change.. including oil tank, superturbocharger, starter, generator, etc.)to the wing and then pulling a giant plane off the ground and through the skies.

As soon as we got it mounted up on the sticks and stepped back to admire the beauty of it all, the sky swarmed with wasps.

My brother swears he heard them all buzzing "Mom!"

Mike

Great thread,, A question ,, The Wright Cyclone 1820 9cyld had a capacity of 202CI ,,or 3.3lt per pot, was this the biggest radial cyld made ? I still have the remains of one from I think from a Lockheed Hudson ,, Most radials seem to have cyld of from 1lt to 2.5lt ,, maybe they were more efficent when kept under 3lt ?,, another thing I noticed was the taper in the bore on these type of engines ,,as much as 25thou to the top of cyld ,,
They were a great design and have a sound of their own ,to make any engineer to tell a kid or the Mrs to ,, Shutup when that sound is heard ! Chris NZ