The Wright Cyclone was a straightforward development of that engine--nine large cylinders around the propeller shaft, like the spokes of a wheel. As a piston moved toward the hub, the cylinder filled with 201 cubic inches of air mixed with gasoline, to be fired by two sparkplugs; the heat was carried away by cooling fins like those on a lawnmower. The Cyclone was designated R- 1820, for radial engine, displacing 1820 ci. The early models developed 575 horsepower at takeoff, less at higher altitudes.
The Cyclone powered most U.S. Army bombers of the 1930s, including the immortal B-17 Flying Fortress. Donald Douglas picked it for a new passenger plane that the airlines thought would be a trimotor. Douglas gave it two, and when the prototype took off and crossed the Continental Divide on only one engine, the airlines never again questioned the reliability of the Cyclone or the plane that became the DC-3, arguably the greatest aircraft of all time.
Other Cyclone-powered planes included the Douglas SBD dive bomber and the Lockheed Hudson light bomber--but not one important fighter. The engine wasn't suited to the high-g stress of fighter combat, probably because of the way lubricating oil reached the cylinders in the early models. Oil leaks and oil starvation are a constant of the Brewster Buffalo story, even in the B-239 that did so well in Finnish service.
There was one exception to the general rule. When the Navy wanted a fast-climbing fighter for convoy duty, it chose a Wildcat variant built by General Motors and powered by an R-1820- 56 Cyclone. The valves, cylinder heads, transmission gears, lubricating system, and supercharger had all been improved. The FM-2 still couldn't match the high-altitude performance of its Grumman cousins with their Pratt & Whitney engines--but then it was designed for low-level work, finding and strafing submarines.
In the end, the Wright Cyclone had a production run of 25 years, and it flew more miles than any other piston-driven aircraft engine ever built. - Dan Ford (with help from Ben Schapiro)
1. It was fast and quick climbing, both in top speed at WEP, 447 MPH and in cruising speed at altitude, where it was faster and higher than any other plane with Recip engines!
2. It was more pointable than any/all other Recip/Prop planes of WW-II by dint of it's Counter-Rotating Propellers and the absence of P effect because of them.
3. It had CL mounted guns. See this quote with foot note at end! "Clustering all the armament in the nose was unlike most other U.S. aircraft which used wing-mounted guns with trajectories set up to crisscross at one or more points in a "convergence zone." Guns mounted in the nose did not suffer from having their useful ranges limited by pattern convergence, meaning good pilots could shoot much farther. A Lightning could reliably hit targets at any range up to 1,000 yd (910 m), whereas other fighters had to pick a single convergence range between 100 and 250 yd (230 m). The clustered weapons had a "buzz saw" effect on any target at the receiving end, making the aircraft effective for strafing as well. The rate of fire on the guns was about 650 rounds per minute for the 20×110 mm cannon round (130 gram shell) at a muzzle velocity of about 2,756 ft/s (840 m/s) and for the .50 inch machine guns (43–48 gram rounds), about 850 rpm at 2,910 ft/s (887 m/s), velocity. Combined rate of fire was over 4,000 rpm with roughly every sixth projectile a 20 mm. The duration of sustained firing for the 20 mm cannon and .50 caliber machine guns was approximately 14 seconds and 35 seconds respectively.http://en.wikipedia.org/wiki/P-38_Lightning#cite_note-18">"
4. It had hydraulically powered ailerons which gave it an exceptional rate of roll at high speeds.
5. It had extraordinary pitch authority at the time, as long as the speed was under 505 Knots at high altitude. But the plane was so fast it could exceed that limit speed very early in a dive which limited it to shallow dives in the attack. It's one great weakness.
6. It had very long range at the time on internal fuel if required, or that extra fuel could yield extraordinary persistence at Maximum Continuous Combat power!
7. It had a huge war Load at the time. over 2,000 pounds on the first models and over 4000 pounds on the late models and over 5,400 pounds on the last models!
8. It was a very tough aircraft and hard to shoot down!
9. Lastly, it had all of these virtues in one plane. While some other planes had some of these virtues, no other plane had more than two or three of them and when you include the pointability factor that it alone had among ALL mass produced planes of WW-II, it is easy to see why it deserves to be the "Best Fighter Plane of WW-II"!
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