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American Combat Planes of the 20th Century is an incredible reference for anyone who is interested in any American Combat Plane History. There are 758 pages and 1700 b/w photos in this substantial labor of love by Ray Wagner, who has been passionately researching and writing about aircraft for over 50 years. Whether you are already familiar with his past works, or just discovering this accomplished author for the first time... This is the book that you've been waiting for!

If you'd like to see the book's Table of Contents ... Click here. You can also browse the entire Index Section to get an idea of the extensive amount of information that is covered within this book.

Search our site for other combat planes. A- 1 Eaton A- 4 Skyhawk A- 6 & A- 7 Air Weapons AV- 8 to A- 10 A- 20 Havoc A- 22 Martin Maryland A- 23 Martin Baltimore A- 24 Douglas A- 26 Douglas Invader Attack Planes B- 2A, F-111, F-117 Stealth B- 17 Flying Fortress B- 24 Liberator B- 25 North American B- 26 Marauder B- 29 Superfortress B- 32 Dominator B- 35 Flying Wing B- 36 B- 47 Stratojet B- 50 Boeing B- 52 Stratofortress B- 57 Canberra B- 58 Hustler Biplanes Biplanes, Army Pursuits Bombers, B- 70 to Stealth Bombers, First Big Curtiss Falcon CO- 1 DH- 4 De Havilland F3D- Douglas Skyknight F3H- McDonnell Demon F4D- 1 Skyray F4F Grumman Wildcats F- 4U Corsair F6F Grumman F7F Grumman F7U Vought F9F G. Cougar F9F G. Panther F- 16 Fighting Falcon F- 84 F- 86 Sabre F- 89 to F-94 F- 100 to F-108 First Fighters Flying Boats GAX Iraq to Afghanistan Martin Bombers Missile Era Fighters Navy Fighers Navy Flying Boats O- 2 Douglas P- 35 Seversky P- 36 to 42 Curtiss P- 38 Lightning P- 39 Airacobra P- 40 Line P- 47 Thunderbolt P- 51 Mustang Fighter P- 61 Black Widow P- 63 Kingcobra P- 79 to P-81 P- 82 Twin Mustang SB2C Helldiver TBF-TBM Avenger Thomas-Morse Torpedo Planes V- 11 Vultee XB -28 XP -48 / 77

The Biplane Period, 1917 to 1932

Page 6

Top speed is the measurement of the airplane’s ability to catch or to escape the enemy. Primarily, it is determined by an aircraft’s power loading and its drag. The lower the power loading, the faster the aircraft, thus the lighter the weight and the greater the power, the higher the speed. The drag of any airframe is steadily reduced as the aircraft gains in altitude, due to the thinning density of the air. Therefore, the higher the altitude of a given power loading, the faster the plane.

As a plane goes higher the air gets thinner and power also decreases; an unsupercharged piston engine will lose a third of its power at 10,000 feet and 60% by 20,000 feet. That condition may be corrected by supercharging that compresses the air so that sea-level pressures and engine power are maintained up to the unit’s critical altitude, where power starts to fall off.

Since thinner air at higher altitudes means less drag, the aircraft can go nearly 1% faster with every 1,000 feet of height, and an airplane makes its highest speed at the altitude at which the advantage of the lower drag is greater than the disadvantage of the loss of power due to the thinning air. This is known as the critical altitude. In unsupercharged airplanes, the critical altitude is at sea level, for the loss of power as the plane goes higher is not compensated by the reduction in drag.

In the Curtiss P-6E, the last unsupercharged Army pursuit, top speed dropped from 198 mph at sea level to 194 at 5,000 feet, l89 at 10,000 feet, and 182 at 15,000 feet. On the other hand, the Boeing 281 had a single-stage supercharger that maintained power into higher altitudes. Top speed therefore went from 215 mph at sea level to 235 at 6,000 feet (its critical altitude), and to 232 at 11,000 feet.

This effect was gained by a built-in, or integral supercharger run by the crankshaft of the engine. Later types used turbosuperchargers, run by the engine exhaust, which are heavier, and can maintain power up to 35,000 feet. The disadvantage of superchargers is their increased weight, which handicaps the supercharged aircraft’s performance at sea level.

As far as fighter aircraft are concerned, rate of climb and ceiling come second only to top speed as performance criteria. Rate of climb is simply the time taken to reach a given altitude, or the feet gained in one minute’s climb. Service ceiling is the altitude at which rate of climb is 100 feet per minute for a fully loaded aircraft, while absolute ceiling is the highest altitude an aircraft may achieve. Service ceiling was the criteria for tactical purposes, and absolute ceiling is no longer cited in government tables after 1938.

The climbing ability of an aircraft is determined by both power loading and wing loading. The lower each is, the better the climb. Unfortunately a low power loading and high speed are not always compatible with a low wing loading and good climb. The larger the wing, the lower the wing loading, but the larger the wing, the more the drag.

Therefore it can be seen that a fast plane with a small wing may not match the climbing ability of a slower plane with a more generous wing area. An example of this was the Japanese Zero, whose low wing loading gave it a distinct advantage in climb and maneuverability over faster American types.

Maneuverability is the plane’s ability to change direction. Wing loading and inertia are determining factors here. Maneuverability is adversely affected by aircraft inertia, or the natural resistance to any rotation about its center of gravity. Any heavy weight at a distance from the center of gravity will make maneuvers more difficult. The more compact and lighter the aircraft, the more maneuverable it will be, often forcing designers to choose between a fighter’s ability to catch his enemy and his ability to maneuver into a good firing position.

Endurance was given in hours and minutes on older aircraft and usually quoted at full throttle. After World War I, Range was a vital characteristic and is determined by the number of hours an aircraft’s fuel will allow it to stay in the air, times the cruising speed. Cruising speed depends on altitude, gross weight, and power used, and thus is very variable. The range of an aircraft also has numerous possibilities depending on the amount of fuel carried. Throughout this book, range is usually given at the normal cruising condition with the usual fuel load. Maximum ranges suggest the possibilities of the plane with its largest possible fuel load, and the most economical speed and altitude. Radius of action is about 40 per cent or less of range.

Running engines at too high a speed may waste fuel, as in this example: With 2,290 gallons of fuel and a gross weight of 55,000 pounds, the B-24D could achieve a range of about 2,950 miles at a cruising speed of 200 mph at 25,000 feet. Increasing the speed to 250 mph reduces the range to 2,400 miles. At an altitude of 5,000 feet, however, B-24D range is only 1,000 miles at 250 mph, and 2,400 miles at 200 mph. The inefficiency of the supercharged engines at lower altitudes is evident. Any increase in the bomb load carried will reduce this range, while a substitution of fuel for bombs can increase the range.

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