20 October 1922: 1st Lieutenant Harold Ross Harris, Air Service, United States Army, the Chief, Flight Test Branch, Engineering Division, at McCook Field, Dayton, Ohio, was test flying a Loening Aeronautical Engineering Company PW-2A monoplane, a single-engine, single-seat fighter. The PW-2A, serial number A.S. 64388, had experimental balance-type ailerons. During this flight, Lieutenant Harris engaged in simulated air combat with Lieutenant Muir Fairchild (future Vice Chief of Staff, United States Air Force) who was flying a Thomas-Morse MB-3.
While banking the PW-2A into a right turn, Harris’ control stick began to vibrate violently from side to side and the airplane’s wings were “torn apart.” With the Loening diving uncontrollably, Harris jumped from the cockpit at approximately 2,500 feet (762 meters). After free-falling about 2,000 feet (610 meters), he pulled the lanyard on his parachute which immediately deployed. Harris then descended with his parachute providing aerodynamic deceleration, coming safely to earth in the back yard of a home at 335 Troy Street. He suffered minor bruises when he landed on a trellis in the garden.
Harris’ PW-2A crashed into a yard at 403 Valley Street, three blocks away. It was completely destroyed.
This was the very first time a free-fall parachute had been used in an actual inflight emergency. Lieutenant Harris became the first member of the Irvin Air Chute Company’s “Caterpillar Club.”
Harold R. Harris was born at Chicago, Illinois, 20 December 1895, the first of four children of Ross Allen Harris, M.D., and Mae Ermine Plumb Harris. He enlisted as a private in the Aviation Section, Signal Enlisted Reserve Corps (E.R.C.), 2 May 1917. He was commissioned as a 2nd Lieutenant, Aviation Section, Signal Officers Reserve Corps (O.R.C.) on 15 December 1917. Harris was promoted to the rank of 1st Lieutenant on 19 January 1918. His commission was vacated 18 September 1920 and commissioned as a 1st Lieutenant, Air Service, United States Army, effective 1 July 1920.
Married Grace C. Harris, circa 1920. They had two children.
Ross attended the Air Service Engineering School, graduating in 1922. He also earned a Bachelor of Science degree (B.S.) from the California Institute of Technology, Pasadena, California (“Caltech”).
Harris left the Air Service in 1926. He founded the world’s first aerial crop dusting business, the Huff Daland Company. Next he became a vice president and chief of operations for Grace Airways, a joint venture of Grace Shipping and Pan American World Airways, providing passenger service between South America and the West Coast of the United States.
During World War II, Harris, using his airline experience, helped to establish the Air Transport Command. In 1942, he was commissioned as a colonel in the U.S. Army Air Corps. By 1945, he was Chief, Air Transport Command, with the rank of Brigadier General.
Following World War II, Harris joined American Overseas Airlines, which soon was absorbed by Pan American. Harris was once again a vice president for Pan Am.
In 1955, Harris became president of Northwest Airlines.
Brigadier General Harold Ross Harris, United States Army Air Corps (Retired) died 28 July 1988 at the age of 92 years.
17 October 1913: On the morning of a scheduled test flight at Flugplatz Johannisthal-Adlershof, an airfield south east of Berlin, Germany, Marine-Luftschiffes L2, the second rigid airship built for the Kaiserliche Marine (Imperial German Navy) by Luftschiffbau Zeppelin at Friedrichshafen, was delayed by problems with the engines. The morning sun heated the hydrogen contained in the airship’s gas bags, causing the gas to expand and increasing the airship’s buoyancy.
Once released, L2 rapidly rose to approximately 2,000 feet (610 meters). The hydrogen expanded even more due to the decreasing atmospheric pressure. To prevent the gas bags from rupturing, the crew vented hydrogen through relief valves located along the bottom of the hull.
In this early design, the builders had placed the relief valves too close to the engine cars. Hydrogen was sucked into the engines’ intakes and detonated. L2 caught fire and a series of explosions took place as it fell to the ground.
All 28 persons on board were either killed immediately, or died of their injuries shortly thereafter.
At the time of the accident, L2 had made ten flights, for a total of 34 hours, 16 minutes.
A contemporary news article described the accident:
AIRSHIP AND BALLOON NEWS.
The Wreck of the Zeppelin.
ELSEWHERE in this issue we comment upon the terrible catastrophe which befell the German Navy’s new Zeppelin L2, on Friday last week, just outside the Johannisthal aerodrome, near Berlin. From the following official account it appears that the airship was making a trial voyage:—
“She started this morning for a high flight, with twenty-eight persons on board. After three minutes she had attained a height of two hundred metres (over 600 feet) when flames burst forth between the fore engine-car and the envelope. In two or three seconds the whole ship was on fire and an explosion occurred. At the same time the airship fell slowly head downwards, until she was forty metres (130 feet) from the earth. Here a second explosion took place, presumably of benzine. When the vessel struck the earth a third explosion occurred, and the framework collapsed. A company of pioneers and guide-rope men hastened to the scene, and doctors were immediately in attendance. Two of the crew were picked up outside the ship still alive, but they died shortly afterwards. Lieut. Bleuel, who was severely injured, was taken to hospital. The remaining 25 of the crew had been killed during the fall of the airship or by the impact with the earth. The cause of the disaster appears to have been, so far as is at present known, an outbreak of fire in or over the fore engine-car.”
The commanding officer was Lieut. Freyer, and he was assisted by Lieuts. A. Trenck, Hansmann, and Busch, with thirteen warrant and petty officers. There were also on board as representing the German Navy, Commander Behnisch, Naval Construtors Neumann, and Pretzker, and three secretaries, named Lehmann, Priess, and Eisele. The Zeppelin Co. were represented by Capt. Glund and three mechanics, and Lieut. Baron von Bleuel was a passenger. The last mentioned was the only one rescued alive, and he died from his injuries a few hours later.
One of the first messages of sympathy was addressed by President Poincare’ to the German Emperor.
Extraordinary scenes, showing the way in which the calamity was regarded in Germany, were witnessed at the funeral service of 23 of the victims, held on Tuesday at the Garrison Church. Upon each of the coffins Prince Adalbert placed a wreath from the German Emperor and Empress, who with the Crown Prince and princess, and Princes Eitel Friedrich, Adalbert, August Wilhelm, Oscar and Joachim attended in person, while the Government was represented by the Chancellor, Admiral Tirpitz, the Chief of the General Staff, Field Marshall von Moltke, and many other officers. Count Zeppelin was also present.
— FLIGHT, First Aero Weekly in the World. No. 252. (No. 43, Vol. V.), 25 October 1913 at Page 1179
The Marine-LuftschiffesL2 had been designated LZ 18 by the builders. Both identifications are commonly used (sometimes, L.II). Technical data for L2 is limited and contradictory. One source describes it as having a length of 158 meters (518 feet, 4½ inches), with a diameter of 16.6 meters (54 feet, 5½ inches). Another states 492 feet.
Eighteen hydrogen-filled gas bags were placed inside the rigid framework and covered with an aerodynamic envelope. The airship had a volume of 27,000 cubic meters (953,496 cubic feet), and a lift capacity of 11.1 tons (24,471 pounds).
Four water-cooled, normally-aspirated, 22.921 liter (1,398.725 cubic inches) Maybach C-X six-cylinder inline engines were carried in two cars beneath the hull. They produced 207 horsepower at 1,250 r.p.m., burning bensin (gasoline). Each engine drove a four-blade propeller through a drive shaft and gear arrangement. These engines weighed 414 kilograms (913 pounds), each.
L2 had a maximum speed of approximately 60 miles per hour (97 kilometers per hour). At reduced speed, L2 had a 70 hour radius of action.
16 October 1956: Pan American World Airways’ Flight 6 was a scheduled around-the-world passenger flight. The final leg, Honolulu to San Francisco, was flown by a Boeing Model 377 Stratocruiser with civil registration N90943, and named Sovereign of the Skies.
The airplane had a flight crew of 7 and carried 24 passengers. The aircraft commander was Captain Richard N. Ogg, a veteran pilot with more than 13,000 flight hours accumulated over twenty years. First Officer George L. Haaker, Flight Engineer Frank Garcia, Jr., and Navigator Richard L. Brown completed the flight crew. The cabin crew were Purser Patricia Reynolds, who had been with Pan Am for over ten years, and Stewardesses Katherine S. Araki and Mary Ellen Daniel.
The flight from Honolulu to San Francisco was estimated to take 8 hours, 54 minutes. Captain Ogg had the airplane fueled for a total flight time of 12 hours, 18 minutes.
Flight 6 departed Honolulu at 8:24 p.m., Hawaii Standard Time, 15 October (06:24, 16 October, GMT), and climbed to 13,000 feet (3,962 meters) on course.
4 hours, 38 minutes after takeoff, Flight 6 requested a pre-planned climb to 21,000 feet (6,400 meters), at a point about half-way—in terms of flight time—between the departure point and destination, what is dramatically called “The Point of No Return” in suspense movies. (Actually, this is called the Equal Time Point: Taking into consideration forecast winds, the time to fly back to the departing point is the same as the time to continue toward the destination.)
On leveling at the new cruise altitude at 1:19 a.m. (HST), First Officer Haaker reduced engine power. The propeller for the Number 1 engine, the outside engine on the left wing, suffered a prop governor failure and began to overspeed, with engine r.p.m. actually exceeding the limits of its tachometer. This created a very dangerous condition: If the propeller turned fast enough, it could be torn apart by centrifugal force. (See This Day In Aviation, 22 March 1956, for an example.)
The crew was unable to feather the propeller, which would cause its four blades to turn parallel to the slip stream, and increasing the load on the engine while reducing aerodynamic drag. The engine and propeller continued to turn at dangerously high speed so Captain Ogg decided to force the engine to stop by cutting off its lubricating oil supply. This caused the engine to seize but the propeller continued to “windmill.”
The drag caused by the propeller slowed the airplane considerably and the three remaining engines had to run at high power for the Boeing 377 to maintain its altitude. The Number 4 engine (the outer engine on the right wing) was developing only partial power at full throttle. At 2:45 a.m., it began to backfire and had to be shut down.
The airplane began to descend toward the ocean’s surface.
With the drag of the windmilling Number 1 propeller and only two engines running, Sovereign of the Skies could fly at just 140 knots (161 miles per hour/259 kilometers per hour), not fast enough to reach San Francisco or to return to Honolulu before running out of fuel. The navigator estimated that they would run out of fuel 250 miles (402 kilometers) from land.
The United States Coast Guard kept a high endurance cutter on station between Hawaii and California, at a point known as Ocean Station November. This ship provided assistance with weather information, radio communications and was available to assist should an emergency arise aboard trans-Pacific airplanes.
On 16 October 1956, this cutter was USCGC Pontchartrain (WHEC 70), under the command of Commander William K. Earle, USCG. Pontchartrain was a 255-foot (77.7 meter) Lake-class patrol gunboat built by the U.S. Coast Guard ship yard at Curtiss Bay, Maryland, and commissioned 28 July 1945. The ship was redesignated as a high endurance cutter in 1948. Pontchartrain had a complement of 143 men.
The ship was 254 feet (77.42 meters) long, overall, with a beam of 43 feet, 1 inch (13.13 meters) and draft of 17 feet, 3 inches (5.25 meters). Its full load displacement was 1,978 tons (1,794 Metric tons). It was powered by a Westinghouse turbo-electric drive of 4,000 shaft horsepower and was capable on making 17.5 knots (20.41 miles per hour, or 32.41 kilometers per hour). Its maximum range was 10,376 miles (19,216 kilometers).
Pontchartrain was armed with a single 5-inch/38-caliber naval gun forward. It carried Hedgehog anti-submarine mortars and Mk 23 acoustic-homing antisubmarine torpedoes.
Captain Ogg notified Ponchartrain that he intended to ditch the airliner near the ship. The Coast Guard provided Captain Ogg with wind and wave information—five-foot (1.5 meter) swells, wind at eight knots (4 meters per second) from the northwest—and advised the best heading for ditching. The ship laid a trail of foam to mark this course.
At 6:15 a.m., at approximately 90 knots airspeed (104 miles per hour/167 kilometers per hour), the Boeing 377 landed on the water. A wing hit a swell, spinning the airplane to the left. The tail broke off and the airplane began to settle.
Injuries were minor and all passengers and crew evacuated the airliner. They were immediately picked up by Pontchartrain.
Captain Ogg and Purser Reynolds were the last to leave the airplane.
Twenty minutes after touching down, at 6:35 a.m., Sovereign of the Skies sank beneath the ocean’s surface.
Pan American’s Sovereign of the Skies was a Boeing Model 377-10-29, construction number 15959, originally operated by American Overseas Airlines as Flagship Holland, and later, Flagship Europe. Pan Am acquired the airliner during a merger. On 16 October 1956, the airplane had accumulated 19,820:51 total time on the airframe (TTAF) since it was built.
The Boeing 377 was a large, four-engine civil transport which had been developed, along with the military C-97 Stratofreighter, from the World War II B-29 Superfortress long-range heavy bomber. It utilized the wings and engines of the improved B-50 Superfortress. The airplane was operated by a flight crew of four. It was a double-deck aircraft, with the flight deck, passenger cabin and galley on the upper deck and a lounge and cargo compartments on the lower. The airliner was pressurized, and could maintain Sea Level atmospheric pressure while flying at 15,500 feet (4,724 meters). The Model 377 could be configured to carry up to 100 passengers, or 28 in sleeping births.
The Stratocruiser was 110 feet, 4 inches (33.630 meters) long with a wingspan of 141 feet, 3 inches (43.053 meters) and overall height of 38 feet, 3 inches (11.659 meters). Empty weight was 83,500 pounds (37,875 kilograms) and the maximum takeoff weight was 148,000 pounds (67,132 kilograms). Sovereign of the Skies had a gross weight of 138,903 pounds (63,005 kilograms) when it took off from Honolulu.
The airliner was powered by four air-cooled, supercharged 4,362.49-cubic-inch-displacement (71.489 liter) Pratt & Whitney Wasp Major B6 four-row, 28-cylinder radial engines which had a Normal Power rating of 2,650 horsepower at 2,550 r.p.m., and 2,800 horsepower at 2,550 r.p.m. Maximum Continuous. It produced 3,250 horsepower at 2,700 r.p.m. for takeoff (3,500 horsepower with water injection). The engines drove four-bladed Hamilton-Standard Hydromatic, 24260 constant-speed propellers with a diameter of 17 feet, 0 inches (5.182 meters) through a 0.375:1 gear reduction. The Wasp Major B6 was 8 feet, 0.50 inches (2.451 meters) long, 4 feet, 7.00 inches (1.397 meters) in diameter, and weighed 3,584 pounds (1,626 kilograms).
The 377 had a cruise speed of 301 miles per hour (484 kilometers per hour) and a maximum speed of 375 miles per hour (604 kilometers per hour). During testing by Boeing, a 377 reached 409 miles per hour (658 kilometers per hour). Its service ceiling was 32,000 feet (9,754 meters) and the range was 4,200 miles (6,759 kilometers).
Boeing built 56 Model 377 Stratocruisers, with Pan American as the primary user, and another 888 military C-97 Stratofreighter and KC-97 Stratotankers.
A U.S. Coast Guard film of the incident can be seen at:
12 October 1954: North American Aviation Chief Engineering Test Pilot George S. Welch, testing the ninth production F-100A-1-NA Super Sabre, serial number 52-5764, made a planned 7.3 G pullout from a Mach 1.55 dive to verify the aircraft’s design limits.
A Boeing B-47 Stratojet crew flying at 25,000 feet (7,620 meters) reported that Welch’s F-100 winged over and began a rapid descent, passing within four miles (6.4 kilometers) of their position and diving at a very high speed. The aircraft appeared to be under control but then suddenly disintegrated.
The Super Sabre had encountered Inertial Roll Coupling. It went out of control and then disintegrated. Its nose folded over the windshield, crushing Welch in his seat. The vertical fin broke away. The ejection seat fired but because of the supersonic speeds the parachute was shredded.
Welch was still alive when rescue teams arrived. He died while being flown to a hospital by helicopter.
Inertial roll coupling led to the death of test pilot Mel Apt when his rocket-powered airplane, the Bell X-2, went out of control at Mach 3.2 It nearly killed Chuck Yeager when he lost control of the Bell X-1B at Mach 2.4. It is a complex phenomenon which I will briefly attempt to explain:
To increase maximum speed of transonic and supersonic airplanes during the late 1940s and early 1950s, their wings and tail surfaces were made smaller in order to decrease aerodynamic drag. At the same time, the fuselage became longer and the placement of engines, armament, landing gear, fuel, etc., within the fuselage concentrated the airplane’s mass near its center. While the gyroscopic effects of the turbojet engine contributed some degree of longitudinal stability, the torque effect made rolls to the left occur more easily, but with a higher rate than a roll to the right. The resistance to a change in attitude—inertia—decreased at the same time that the control surfaces’ ability to control the airplanes’ attitude also decreased. The airplanes became unstable.
When George Welch tried to pull the F-100 out of its supersonic dive, the airplane’s speed began to decrease as the angle of attack increased. The wings’ ability to stabilize the natural roll instability of the fuselage’s concentrated mass was lessened, and the ailerons could not provide sufficient control to counteract this rolling tendency. The low vertical fin of the original F-100A did not provide adequate directional stability. The Super Sabre rolled and then yawed, entering a side slip. This caused the Super Sabre to pitch down and it was suddenly out of control in all three axes. The physical forces exceeded the strength of the aircraft structure and it came apart.¹
[Aerodynamicists and Aeronautical Engineers: Your corrective comments are welcome.]
Following the death of George Welch, NACA High Speed Flight Station research test pilot Albert Scott Crossfield spent three months conducting flight tests of the F-100A, demonstrating its inertial roll coupling characteristics using three different vertical fins. F-100A-5-NA 52-5778 was Crossfield’s test aircraft.
The North American Aviation F-100 Super Sabre was designed as a supersonic day fighter. Initially intended as an improved F-86D and F-86E, it soon developed into an almost completely new airplane. The fuselage incorporated the “area rule,” a narrowing in the fuselage width at the wings to increase transonic performance, similar to the Convair F-102A. The Super Sabre had a 49° 2′ sweep to the leading edges of the wings and horizontal stabilizer. The ailerons were placed inboard on the wings and there were no flaps, resulting in a high stall speed in landing configuration. The horizontal stabilizer was moved to the bottom of the fuselage to keep it out of the turbulence created by the wings at high angles of attack. The F-100A had a distinctively shorter vertical fin than the YF-100A. The upper segment of the vertical fin was swept 49° 43′.
There were two service test prototypes, designated YF-100A, followed by the production F-100A series. The first ten production aircraft (all of the Block 1 variants) were used in the flight testing program.
The F-100A Super Sabre was 47 feet, 1¼ inches (14.357 meters) long with a wingspan of 36 feet, 6 inches (11.125 meters). With the shorter vertical fin, the initial F-100As had an overall height of 13 feet, 4 inches (4.064 meters), 11 inches (27.9 centimeters) less than the YF-100A.
The F-100A had an empty weight of 18,135 pounds (8,226 kilograms), and gross weight of 28,899 pounds (13,108 kilograms). Maximum takeoff weight was 35,600 pounds (16,148 kilograms). It had an internal fuel capacity of 755 gallons (2,858 liters) and could carry two 275 gallon (1,041 liter) external fuel tanks.
The early F-100As were powered by a Pratt & Whitney Turbo Wasp J57-P-7 afterburning turbojet engine. It was rated at 9,700 pounds of thrust (43.148 kilonewtons) for takeoff, and 14,800 pounds (65.834 kilonewtons) with afterburner. Later production aircraft used a J57-P-39 engine. The J57 was a two-spool axial flow turbojet which had a 16-stage compressor, and a 3-stage turbine. (Both had high- and low-pressure stages.) The engine was 15 feet, 3.5 inches (4.661 meters) long, 3 feet, 5.0 inches (1.041 meters) in diameter, and weighed 4,390 pounds (1,991 kilograms).
The Super Sabre was the first U.S. Air Force fighter capable of supersonic speed in level flight. It could reach 760 miles per hour (1,223 kilometers) at Sea Level. (Mach 1 is 761.1 miles per hour, 1,224.9 kilometers per hour, under standard atmospheric conditions.) Its maximum speed was 852 miles per hour (1,371 kilometers per hour) at 35,000 feet (10,668 meters). The service ceiling was 44,900 feet (13,686 meters). Maximum range with external fuel was 1,489 miles (2,396 kilometers).
The F-100 was armed with four M-39 20 mm autocannons, capable of firing at a rate of 1,500 rounds per minute. The ammunition capacity of the F-100 was 200 rounds per gun.
North American Aviation built 199 F-100A Super Sabres at its Inglewood, California, plant before production shifted to the F-100C fighter bomber variant. Approximately 25% of all F-100As were lost in accidents.
George Welch was born George Lewis Schwartz, Jr., in Wilmington, Delaware, 10 May 1918. He was the first of two sons of George Lewis Schwartz, a chemist at the Dupont Experimental Station in Wilmington, and Julia Welch Schwartz. His parents changed his surname to Welch, his mother’s maiden name, so that he would not be effected by the anti-German prejudice that was widespread in America following World War I.
He studied mechanical engineering at Purdue University, Indiana, and enlisted in the Army Air Corps in 1939. Welch graduated from pilot training at Kelly Field, Texas, and on 4 October 1940, was commissioned as a second lieutenant, U.S. Army Air Corps.
George S. Welch is best remembered as one of the heroes of Pearl Harbor. He, along with Second Lieutenant Kenneth M. Taylor, were the only two fighter pilots to get airborne from Haleiwa Auxiliary Airfield during the Japanese surprise attack on Hawaii, 7 December 1941. Flying a Curtiss P-40B Warhawk, he shot down three Aichi D3A “Val” dive bombers and one Mitsubishi A6M2 Zero fighter. Taylor also shot down four Japanese airplanes. For this action, Lieutenant General Henry H. “Hap” Arnold recommended the Medal of Honor, but because Lieutenants Welch and Taylor had taken off without orders, an officer in their chain of command refused to endorse the nomination. Both fighter pilots were awarded the Distinguished Service Cross.
During the War, Welch flew the Bell P-39 Airacobra and Lockheed P-38 Lightning on 348 combat missions. He had 16 confirmed aerial victories over Japanese airplanes and rose to the rank of Major. In addition to the Distinguished Service Cross, George Welch was awarded the Silver Star, the Distinguished Flying Cross with two oak leaf clusters (three awards), the Air Medal with one oak leaf cluster (two awards), the Presidential Unit Citation with two oak leaf clusters (three awards), American Defense Service medal with one service star, American Campaign Medal, Asiatic-Pacific Campaign Medal with one silver and one bronze star (six campaigns), and the World War II Victory Medal.
Welch received the nickname, “Wheaties,” because he was the first military officer to be featured on a box of Wheaties cereal. (Wheaties, “The Breakfast of Champions,” was a toasted wheat bran cereal produced by General Mills. It normally featured champion athletes on its distinctive orange-colored boxes.)
Suffering from malaria, George Welch was out of combat and recuperating in Australia. There he met Miss Janette Alice Williams and they were soon married. Welch returned to the United States with his new wife. They had a son, Giles, born in October 1947. Their home was in Brentwood, California.
North American Aviation approached General Arnold to recommend a fighter pilot who could bring his combat experience to testing new fighters. Welch was one of two that General Arnold suggested. The general authorized Welch’s release from active duty so that he could join North American. Welch held the rank of major, Air Reserve, from 13 November 1944 to 1 April 1953.
Welch went on to test fly the North American P-51H Mustang, FJ-1 Fury, F-86 Sabre and F-100 Super Sabre.
George Welch made the first flight of the XP-86 prototype, 1 October 1947. There is some evidence that on that flight, and during a subsequent flight on 14 October, Welch exceeded the speed of sound while in a dive. It has been said that during the Korean War, while teaching U.S. Air Force pilots how to best use the F-86 Sabre, he shot down several enemy MiG-15 jet fighters.
George S. Welch is buried at the Arlington National Cemetery, Section 6, Site 8578-D.
¹ Recommended: Coupling Dynamics in Aircraft: A Historical Perspective, by Richard E. Day, Dryden Flight Research Center, Edwards AFB, California. NASA Special Publications 532, 1997.
5 October 1930: Two days after receiving its Certificate of Airworthiness from the Air Ministry, the British rigid airship R.101, registration G-FAAW, was on its maiden voyage from Cardington, Bedfordshire, England, to Karachi, India, with 12 passengers and a crew of 42. The new airship was under the command of Flight Lieutenant Herbert Carmichael (“Bird”) Irwin, AFC, Royal Air Force, a highly experienced airship commander.
Among the passengers were Lord Thomson, Secretary of State for Air, Sir Sefton Brancker, Director of Civil Aviation, and several senior Royal Air Force officers who had been involved in the planning and development of the airship.
R.101 was the largest aircraft that had been built up to that time. Not until the Hindenburg was built five years later would there be anything bigger. Its teardrop shape and been developed in wind tunnel testing and actual flights with R33, which had been extensively modified to obtain detailed flight data.
R.101 required a minimum flight crew of fifteen: a first officer, two second officers, two helmsmen and ten engineers.
The airship was 777 feet, 2½ inches (236.893 meters) long and 131 feet, 9 inches (40.157 meters) in diameter. The airship had an overall height of 141 feet, 7 inches (43.155 meters). Built of stainless steel girders which were designed and built by Boulton & Paul Ltd., and covered with doped fabric, buoyancy was created by hydrogen gas contained in bags spaced throughout the envelope. The maximum gas capacity of the airship was 5,508,800 cubic feet (155,992 cubic meters). The hydrogen weighed 71.2 pounds per 1,000 cubic feet (32.3 kilograms/28.3 cubic meters). The airship’s fuel capacity was 9,408 gallons (42,770 liters) and it carried 215 gallons (977 liters) of lubricating oil.
R.101 was powered by five steam-cooled, 5,131.79-cubic-inch-displacement (84.095 liters) William Beardmore & Company Ltd. Tornado Mark III inline 8-cylinder heavy-oil compression-ignition (diesel) engines. These were developed from railroad engines. Each engine weighed 4,773 pounds (2,165 kilograms). They could produce 650 horsepower, each, at 935 r.p.m., but because of vibrations resulting from the very long crankshaft, engine speed was reduced to 890 r.pm., which decreased power output to 585 horsepower. The engines turned 16 foot (4.877 meter) diameter two-bladed wooden propellers, which gave R101 a maximum speed of 71 miles per hour (114.3 kilometers per hour), with a sustained cruising speed of 63 miles per hour (101.4 kilometers per hour). Two of the engines, designated Mark IIIR, could be stopped then restarted to run in the opposite direction to slow or reverse the airship.
The airship had an empty weight of 113 tons (114,813 kilograms), and 169.85 tons (380,464 kilograms) of gross lift capacity.
R.101 departed its base at Cardington, Bedfordshire, on 4 October and soon encountered rain and high winds which continually blew it off course. The course was constantly adjusted to compensate and by 2:00 a.m., 5 October, the airship was in the vicinity of Beauvais Ridge in northern France, “which is an area notorious for turbulent wind conditions.”
At 0207 hours, R.101 went into an 18° dive which lasted approximately 90 seconds before the flight crew was able to recover. It then went into a second 18° degree dive and impacted the ground at 13.8 miles per hour (22.2 kilometers per hour). There was a second impact about 60 feet (18 meters) further on and as the airship lost buoyancy from the ruptured hydrogen bags, it settled to the ground. Escaping hydrogen was ignited and the entire airship was engulfed in flames. Of the 54 persons on board, only 8 escaped, but 2 of those would soon die from injuries in the hospital at Beauvais.
This was a national disaster. The dead were honored with a state funeral, and all 48 lay in state at the Palace of Westminster.
The cause of the crash of R.101 is uncertain, but it is apparent that for some reason it rapidly lost buoyancy forward. It was considered to have been very well designed and built, but as it was state-of-the-art, some of the design decisions may have led to the disaster.