National Geographic : 1950 Sep
283 Harold (. Martin (lower) A New Fighter Tries Oddly Shaped Wings; Another Dumps Fuel from Wing-tip Tanks Most wings taper toward the ends, but those of Republic's XF-91 (top), experimental high-altitude Air Force interceptor-fighter, are widest and thickest at the tips. They slant sharply backward and can be turned up or down in flight to increase or lessen their lift (pages 287-8). That stout tail is designed to hold both jet and rocket engines; top speed is a military secret. Over Long Island, a Navy carrier-borne jet fighter, the Grumman F9F Panther, shows how it jettisons fuel instead of dropping costly wingtip tanks before combat. looks as if it's going about 800 miles an hour just sitting on the ground." Flexible swept-back wings of Boeing's B-47 Stratojet bomber are so thin that they droop when the plane is at rest. They bend the other way when they carry the weight of the six-jet bomber, as big as a Superfortress (page 294). In flight they flex like a fly rod, as much as seven feet at the tips. "You sit there and watch 'em wave at you," grinned Bob Robbins, former B-47 project pilot and now an assistant project engineer. "They take up a lot of the shock and give you a nice smooth ride in rough air." Much of the necessary strength is in the aluminum alloy "skin," up to five-eighths of an inch thick. This newest operational Air Force bomber is a good example of how the contributions of many men make a modern plane. Experi mental models wore out brakes and tires, so "hot" was the plane in landing. "Look, why don't you use a chute to slow her down?" drawled an Air Force test pilot, Maj. Guy M. Townsend. "We used to toss out our chutes during the war when our brakes were shot out, and it worked fine." The result was the parachute brake, now standard on the Stratojet (page 308). Little Herbert Joins the Crew Another result of flight tests was "Little Herbert," who got his start in a junk yard. Test-flying the Stratojet at Larson Air Force Base, Moses Lake, Washington, pilots found that it sometimes had a "Dutch roll," swinging one way, then the other, like a waltzer on skates.