2 November 1947: Howard Hughes’ Hughes Aircraft Company H-4 Hercules flying boat, NX37602, made its first and only flight at the harbor of Los Angeles, California. The new media called it “The Spruce Goose” due to its strong but lightweight wooden construction. As with the famous de Havilland DH.98 Mosquito fighter-bomber, the use of wood freed up valuable metal alloys during World War II.
Conceived by Henry J. Kaiser, the airplane was initially called the HK-1. It was designed to carry as many as 750 fully-equipped soldiers on transoceanic flights.
The H-4 is 218 feet, 8 inches (66.650 meters) long with a wingspan of 320 feet, 11 inches (97.815 meters). Its height is 79 feet, 4 inches (24.181 meters). The Hercules’ designed loaded weight is 400,000 pounds (181,437 kilograms).
Eight 4,362.49-cubic-inch-displacement (71.489 liter) air-cooled, supercharged Pratt & Whitney Wasp Major VSB11-G (R-4360-4A) four-row 28-cylinder radial engines with a compression ratio of 7:1. The R-4360-4A had a Normal Power rating of 2,500 horsepower at 2,550 r.p.m. to 5,000 feet (1,524 meters), 2,200 horsepower at 2,550 r.p.m. to 14,500 feet (4,420 meters), and a Takeoff rating of 3,000 horsepower at 2,700 r.p.m. The Military Power rating was also 3,000 horsepower at 2,700 r.p.m., to an altitude of 1,500 feet (457 meters), then decreased to 2,400 horsepower at 2,700 r.p.m. to 13,500 feet (4,115 meters). The engines turned four-bladed Hamilton Standard propellers with a diameters of 17 feet, 2 inches (5.232 meters) through a 0.425:1 gear reduction. The R-4360-4A was 8 feet, 0.75 inches (2.457 meters) long, 4 feet, 4.50 inches (1.334 meters) in diameter, and weighed 3,390 pounds (1,538 kilograms).
On its only flight, the H-4 Hercules traveled approximately one mile (1.6 kilometers) at 135 miles per hour (217 kilometers per hour), remaining in ground effect. It never flew again, and its estimated performance was never verified through flight testing.
The airplane is on display at the Evergreen Aviation and Space Museum, McMinnville, Oregon.
13 September 1935: Flying his Hughes H-1 Special, NR258Y, Howard Robard Hughes, Jr. set a Fédération Aéronautique Internationale (FAI) World Record for Speed Over a 3 Kilometer Course near Santa Ana, California. Making four passes over the measured course, two in each direction, his average speed was 567.12 kilometers per hour (352.39 miles per hour).¹ This was 61.27 kilometers per hour (38.07 miles per hour) faster than the previous record which had been set by Raymond Delmotte, 24 December 1934.
Just after completing the final pass over the course, the airplane’s engine stopped due to fuel starvation. Hughes made a belly landing in a farm field. He was uninjured and the airplane received only minor damage.
The Hughes H-1 (Fedral Aviation Administration records identify the airplane as the Hughes Model 1B, serial number 1) was a single-seat, single-engine low-wing monoplane with retractable landing gear. Emphasis had been placed on an aerodynamically clean design and featured flush riveting on the aluminum skin of the fuselage. The airplane was 27 feet, 0 inches long (8.230 meters) with a wingspan of 25 feet (7.6 meters) and height of 8 feet (2.438 meters). (A second set of wings with a span of 31 feet, 9 inches (9.677 meters) was used on Hughes’ transcontinental flight, 19 January 1937). The H-1 has an empty weight of 3,565 pounds (1,617 kilograms) and gross weight of 5,492 pounds (2,491 kilograms).
The H-1 was powered by a air-cooled, supercharged 1,534.943-cubic-inch-displacement (25.153 liter) Pratt & Whitney Twin Wasp Jr. two-row, fourteen-cylinder radial engine. Pratt & Whitney produced 18 civil and 22 military (R-1535) versions of the Twin Wasp Jr., in both direct-drive and geared configurations, rated from 650 to 950 horsepower. It is not known which version powered the H-1, but various sources report that it was rated from 700 to 1,000 horsepower. The engine drove a two-bladed Hamilton Standard controllable pitch propeller.
7 July 1946: At the Hughes Aircraft Company’s private airport in Culver City, California, the first of two prototype XF-11 photographic reconnaissance airplanes took of on its first flight. In the cockpit was Howard Robard Hughes, Jr.
The Hughes XF-11 was designed to be flown by a pilot and a navigator/photographer. Its configuration was similar to the Lockheed P-38 Lightning and Northrop P-61 Black Widow, as well as the earlier Hughes D-2. The prototype was 65 feet, 5 inches (19.939 meters) long with a wingspan of 101 feet, 4 inches (30.886 meters) and height of 23 feet, 2 inches (7.061 meters). The empty weight was 37,100 pounds (16,828.3 kilograms) and maximum takeoff weight was 58,300 pounds (26,444.4 kilograms).
The XF-11 was powered by two air-cooled, supercharged 4,362.49-cubic-inch-displacement (71.49 liter) air-cooled, supercharged Pratt & Whitney R-4360-31 (Wasp Major TSB1-GD) four row, 28-cylinder radial engines. This engine had a compression ratio of 7:1. It had a normal power rating of 2,550 horsepower at 2,550 r.p.m. at 5,000 feet (1,524 meters), and 3,000 horsepower at 2,700 r.p.m. for takeoff. The R-4360-31 was 4 feet, 4.50 inches (1.334 meters) in diameter, 9 feet, 6.25 inches (2.902 meters) long and weighed 3,506 pounds (1,590 kilograms). The engines drove a pair of counter-rotating four-bladed propellers through a 0.381:1 gear reduction.
The planned maximum speed was 450 miles per hour (724 kilometers per hour), service ceiling 44,000 feet (13,411 meters) and planned range was 5,000 miles (8,047 kilometers).
After about an hour of flight, a hydraulic fluid leak caused the rear propeller of the right engine to go into reverse pitch. Rather than shutting the engine down and feathering the propellers to reduce aerodynamic drag, Hughes maintained full power on the right engine but reduced power on the left, attempting to limit adverse yaw to the right side.
Unable to make it back to the Culver City airport, Hughes planned to land at the Los Angeles Country Club. At 7:20 p.m., the airplane crashed into three houses on North Whittier Drive, Beverly Hills, California. The fire destroyed the prototype and one of the houses and heavily damaged the others. Howard Hughes was seriously injured in the crash.
The investigating board criticized Hughes for not following the flight test plan, staying airborne too long, and deviating from a number of standard test flight protocols. The cause of the actual crash was determined to be pilot error.
A second XF-11 was completed and flew in April 1947, again with Hughes in the cockpit. The project was cancelled however, in favor of the Northrop F-15 Reporter and Boeing RB-50 Superfortress, which were reconnaissance aircraft based on existing combat models already in production.
26 March 1926: Allison Engine Company test pilot Jack Schweibold flew the third prototype Hughes Aircraft Company YOH-6A Light Observation Helicopter, 62-4213, to set three Fédération Aéronautique Internationale (FAI) World Records for Distance Over a Closed Circuit Without Landing of 2,800.20 kilometers (1,739.96 miles), including an Absolute Record for Class E (Rotorcraft).¹ These records still stand.
One week earlier, 20 March 1966, Hughes Aircraft Company test pilot Jack L. Zimmerman flew the same helicopter to set another distance record of of 1,700.12 kilometers (1,056.41 miles).² One 27 March, Zimmerman would set six more world records with 62-4213.³
Jack Schweibold wrote about the record flight in his autobiography, In the Safety of His Wings (Holy Fire Publishing, DeLand, Florida, 2005). He was one of a group of military and civilian test pilots selected to attempt a series of world record flights, using the number three prototype Hughes YOH-6A, 62-4213, from 20 March to 7 April 1966.
The record attempt began at midnight to take advantage of the cold desert air. The cold-soaked YOH-6A had been fueled with pre-cooled JP-5 in order to get the maximum amount of fuel on board. In addition to the standard fuel tank, two auxiliary tanks were placed in the cabin. The helicopter was so heavy from the overload that it could not hover. Jack made a running take-off, sliding the skids across the concrete until the increasing translational lift allowed the aircraft to break free. He began a very shallow climb.
Schweibold was flying a 60 kilometer (37.28 miles) closed course, but because of the near total darkness, he flew on instruments and was guided from the ground by Air Force test range radar controllers (Spatial Positioning and Orientation Radar Tracking, call sign SPORT). Accuracy was critical. The attempt would be disqualified if the helicopter cut inside of a pylon—which Jack could not see—but if he flew too far outside, the extra distance flown would not be counted and time would be lost. The maximum range would be controlled by the amount of fuel carried in the three tanks, and by the endurance of the pilot.
Throughout the flight, Jack gradually increased the altitude, as the T-63-A-5 turboshaft would be more efficient in thinner, colder air. He was flying a precisely calculated profile, taking into consideration aerodynamic drag, the efficiency of the helicopter’s rotor system, and the performance characteristics of the engine. He had been airborne for four hours before he climbed through 10,000 feet (3,048 meters).
At 14,000 feet (4,267 meters), Schweibold was on oxygen. He continued through 20,000 feet (6,096 meters) but was having trouble staying alert. (It would later be discovered that there was a malfunction in his oxygen mask.)
On the final lap, at 22,000 feet (6,706 meters) Jack had to fly around a towering cumulus cloud and radar contact was lost. He dived to lose altitude and popped out from under the cloud about a half-mile short of the runway.
When he shut down the engine, Jack Schweibold had flown the prototype YOH-6A 2800.20 kilometers (1,739.96 statute miles), non-stop. His record still stands.
Jack set 30 FAI World Records between 1966 and 1986. 26 of these remain current.
Frederick Jack Schweibold was born at Toledo, Ohio, 8 November 1935, the son of Henry E. and Jeanette Schweibold. He attended Ohio State University and majored engineering. He had enlisted in the United States Navy Reserve in 1952 and the joined the United States Air Force in 1954 as an Aviation Cadet. Schweibold went through pilot training at Randolph Air Force Base, San Antonio, Texas, flying the T-34 and T-28. He went on to train in the B-25 at Reese Air Force Base, Lubbock, Texas. Schweibold was commissioned as a second lieutenant and received his pilot’s wings in July 1957. In momentary decision, he selected helicopter training.
Lieutenant Schweibold flew the Sikorsky H-19B for the Air Rescue Service, assigned to Oxnard Air Force Base, California. (The airfield is now Camarillo Airport, CMA, where I first soloed, and is about ten miles away from my desk.)
After leaving the Air Force, Jack flew Sikorsky S-55s for Chicago Helicopter Service, then Bell 47s for Butler Aviation. In 1960, he was hired by the Allison Division of General Motors as a test pilot and engineer for the new 250-series turboshaft engine.
I had the good fortune to have known Jack Schweibold. I first met him through his involvement in the Helicopter Association International biennial flight instructor recertification seminars, held during the HAI’s annual convention. He kept the seminar classes on track, and in between, was always available for questions. He was the authority on Allison’s 250-series turboshaft engines, and over the years I often called him for technical information and operational advice. On top of that, Jack Schweibold was just an all-around nice guy.
The Hughes Model 369 was built in response to a U.S. Army requirement for a Light Observation Helicopter (“L.O.H.”). It was designated YOH-6A, and the first aircraft received U.S. Army serial number 62-4211. It competed with prototypes from Bell Helicopter Company (YOH-4) and Fairchild-Hiller (YOH-5). All three aircraft were powered by a lightweight Allison Engine Company turboshaft engine. The YOH-6A won the three-way competition and was ordered into production as the OH-6A Cayuse. It was nicknamed “loach,” an acronym for L.O.H.
The YOH-6A was a two-place light helicopter, flown by a single pilot. It had a four-bladed, articulated main rotor which turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) Stacks of thin stainless steel “straps” fastened the rotor blades to the mast and also allowed for flapping and feathering. Hydraulic dampers controlled lead-lag. Originally, there were blade cuffs around the main rotor blade roots in an attempt to reduce aerodynamic drag, but these were soon discarded. A two-bladed semi-rigid tail rotor was mounted on the left side of the tail boom. Seen from the left, the tail-rotor rotates counter-clockwise. (The advancing blade is on top.)
The YOH-6A was powered by a T63-A-5 turboshaft engine (Allison Model 250-C10) mounted behind the cabin at a 45° angle. The engine was rated at 212 shaft horsepower at 52,142 r.p.m. (102% N1) and 693 °C. turbine outlet temperature for maximum continuous power, and 250 shaft horsepower at 738 °C., 5-minute limit, for takeoff. Production OH-6A helicopters used the slightly more powerful T63-A-5A (250-C10A) engine.
The Hughes Tool Company Aircraft Division built 1,420 OH-6A Cayuse helicopters for the U.S. Army. The helicopter remains in production as AH-6C and MH-6 military helicopters, and the MD500E and MD530F civil aircraft.
Hughes YOH-6A 62-4213 is in the collection of the United States Army Aviation Museum, Fort Rucker, Alabama.
¹ FAI Record File Numbers 786, 787 and 11656
² FAI Record File Number 762
³ FAI Record File Numbers 771, 772, 9920, 9921, 9922, and 9923
19 January 1937: Howard Robard Hughes, Jr., departed Union Air Terminal, Burbank, California, at 2:14 a.m., Pacific Standard Time (10:14 UTC) aboard his Hughes Aircraft Company H-1 Racer, NR258Y. He flew non-stop across the continent to Newark Metropolitan Airport, Newark, New Jersey, and arrived overhead at 12:42:25 p.m., Eastern Standard Time (17:42:25 UTC).
Hughes completed the 2,490-mile (4,007.3 kilometer) flight in 7 hours, 28 minutes, 25 seconds, at an average speed of 332 miles per hour (534 kilometers per hour). He broke the existing record, which he himself had set just over one year previously in a Northrop Gamma, by more than two hours.²
The New York Times reported:
All landplane distance speed records were broken yesterday by Howard Hughes, millionaire sportsman pilot, who reached Newark Airport 7 hours 28 minutes and 25 seconds after he took off from Los Angeles, Calif. He was forced to stay aloft until the runway at the field was clear and landed at 1:03 P.M. His average speed was 332 miles an hour for the 2,490 miles he traveled.
Grimy from the smoke of his exhaust stacks the lanky pilot climbed out of his cramped cockpit and grinned. In recounting his experiences on the flight he said that the skies were overcast all the way and he had to fly on top of the clouds . . .
It was 2:14 o’clock in the morning and pitch dark when he opened the throttle at the Union Air Terminal at Burbank and released the 1,100 horsepower sealed in the fourteen cylinders of his supercharged Twin Row Wasp engine. The sleek gray and ble low-winged monoplane, designed and built under his own direction, staggered, accelerated and then literally vaulted into the air. Within a few seconds Hughes climbed into the low-hanging clouds and swung eastward . . .
At 14,000 feet, at which altitude he flew most of the way, he passed over the clouds, set his course and leveled off. He throttled his engine back until it was delivering only 375 horsepower and hunched himself over his instrument panel . . .
His arrival at Newark was unheralded and a surprise. It was thought that he was going to land at Chicago. The new United Air Lines extra-fare plane was loaded for its initial run and already had its door locked when the propeller whir of the hurling racer apparently made the buildings tremble from sound vibration as Hughes swept low across the field. William Zint of the Longines Watch Company, official timer for the National Aeronautic Association, noted the time. It was exactly 42 minutes and 25 seconds after noon.
Hughes pulled up in a sweeping chandelle maneuver and circled. The United Air Liner was already on the runway when Hughes swung back toward the flaps on his wing to slacken speed for landing . . . and the plane settled fast toward the earth. Still the pilot had no signal from the control tower where the dispatchers act as traffic patrols at the busiest airport in the world. Hughes had to open his throttle again and cruise around the field for some time before the green light at last came on. The United plane was then well on its course toward Chicago. Hughes’s plane slid in over the airport boundary, dropped it’s retractable undercarriage and tail wheel and touched both wheels and tail wheel in a perfect three-point landing at 1:02:30 P.M. . . .
— Excerpted from an article in The New York Times, Wednesday, 20 January 1937, Page 1 at Columns 6 and 7.
After landing at Newark, Hughes told newspaper reporters, “I flew at 14,000 feet most of the way,” Hughes said, “with my highest speed 370 miles an hour. I used about 200 of the 280-gallon load. I am very tired—a bit shaky.”
[Richard W.] Palmer met Hughes at Newark Airport. The two men shook their heads at each other. “I knew she was fast,” Hughes told his chief engineer, “but I didn’t know she was that fast.”
— Newark, N.J., Tuesday, Jan. 19.—(AP)
The Hughes H-1 (FAA records describe the airplane as a Hughes Model 1B, serial number 1) was a single-seat, single-engine low wing monoplane with retractable landing gear. Emphasis had been placed on an aerodynamically clean design and featured flush riveting on the aluminum skin of the fuselage. The airplane is 27 feet, 0 inches long (8.230 meters) with a wingspan of 31 feet, 9 inches (9.677 meters) and height of 8 feet (2.438 meters). (A second set of wings with a span of 25 feet (7.6 meters) was used on Hughes’ World Speed Record¹ flight, 13 September 1935.) The H-1 has an empty weight of 3,565 pounds (1,617 kilograms) and gross weight of 5,492 pounds (2,491 kilograms).
The H-1 was powered by an air-cooled, supercharged, 1,534.94-cubic-inch-displacement (25.153 liter) Pratt & Whitney Twin Wasp Jr., a two-row, fourteen-cylinder radial engine. Pratt & Whitney produced 18 civil and 22 military versions of the Twin Wasp Jr., in both direct drive and geared configurations, rated from 650 to 950 horsepower. It is not known which version powered the H-1, but various sources report that it was rated from 700 to 1,000 horsepower. The engine drove a two-bladed Hamilton Standard controllable-pitch propeller.
¹ FAI Record File Number 8748: World Record for Speed Over a 3 Kilometer Course, 567.12 kilometers per hour (352.39 miles per hour)
² FAI Record File Number 13237: World Record for Speed Over a Recognized Course, 417.0 kilometers per hour (259.1 miles per hour)