Today, we fly P-40s. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Did you happen to see the comic book movie, Sky Captain and the World of Tomorrow? It was a futuristic vision -- a hokey 1940s comic book version of what the world of 2004 might be.

In the movie, Sky Captain flies all over the world fighting evil beings who use monstrous futuristic technology. And his air-plane is a P-40 fighter plane. He crosses oceans in it -- beards the dragon in its den with a machine from back when the last horse-drawn vehicles still traveled our city streets.

The P-40 is a familiar single-seat, low-wing, propeller-driven fighter with a big air-scoop under the nose. When Claire Chennault's Flying Tigers, fought the Japanese so effectively in China during WW-II, they had P-40s with shark's teeth painted on the air scoops -- threatening to eat their enemies for breakfast.

Almost all WW-II fighters were single-seat, low-wing monoplanes with one large variation: They had either a wide radial air-cooled engine, or a long narrow liquid-cooled in-line engine -- a trade between the greater drag of a radial engine and the complicated cooling system on a streamlined in-line engine.

The long evolution of the P-40 actually began with the Curtiss P-36, around 1935. The P-36, with its radial engine, was a neat precursor to the WW-II fighters. But it arrived too early on the scene. War was still several years away, and airplane development would keep moving beyond it.

So its designer, Don Berlin, opted for a radical change. Throw out the radial engine and replace it with a thousand-plus horse-power Allison liquid-cooled engine. That, of course was no minor surgery. The new airplane went through several models with its air-scoop appearing in different locations under the fuselage. 

Finally production models came out in 1940. They had that distinctive jaw just begging pilots to paint sharks' teeth on it. Before we entered the war, they went to our allies. And, if you're of a certain age, you certainly remember the Flying Tigers' P-40s.

Yet the P-40 was still too early. Fifteen thousand were made, in revisions that went all the way up to a P-40Q. Called Tomahawks, Warhawks, or Kittyhawks, they never did catch up with the Mustang or the Messerschmitt 109 -- the Thunderbolt or the Focke-Wulfe 190. The widely-used P-40N still couldn't reach 380 miles-per-hour. And its range was a scant 240 miles. (That, by the way, adds to the fun of watching Sky Captain cross oceans in his P-40.)

Nevertheless, they were the WW-II fighter planes we best remember. Their clean beautiful lines are part of the reason. They made our prefect metaphor during the early war effort. We used them to sell War Bonds and boost civilian morale. Authentic heroes had used them to slow the Japanese juggernaut in China. Add up the pieces, and the P-40 really is the only airplane that our hero Sky Captain could use in his 21st-century battle to rid the world of evil! 

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

For more on the history of the P-40, see: E. R. McDowell, Curtiss P-40 in Action (Don Greer, illustrator) (Squadron/Signal Pubs. Inc., 1976). See also the following website: https://en.wikipedia.org/wiki/Curtiss_P-40

Specifications for the P-40N
     1360hp Allison V-1710-81 inline piston engine
     Weight: empty 6,000 lbs., maximum takeoff 11,400 lbs
     Wingspan: 37ft. 4in., length: 33ft. 4in.
     Maximum Speed at 10,000ft: 378 mph
     Ceiling: 38,000ft; range: 240 miles with no external tanks
     Armament: 12.7 mm wing-mounted machine guns
          up to 1,500lbs of bombs 

This image and the one below are from a WW-II advertising booklet for the Coca-Cola Company: Know Your War Planes (paintings by William Heaslip) (Atlanta, GA, Coca-Cola Company, 1943) 


Idyllic image of a Flying Tiger sharing a coke with a Chinese soldier. Note the shark's teeth in the background. 


Silhouette views of the P-40F, serve to emphasize the clean simplicity of its form. (Image from W. Pitkin, Jr., What's That Plane? (2nd ed.) (New York: Penguin Books, Inc., 1942/1943).