Tag Archives: Flying Boat

11 January 1938

A Pan American Airways Sikorsky S-42.
A Pan American Airways Sikorsky S-42.

11 January 1938: Pan American Airways’ Sikorsky S-42B NC16734, Samoan Clipper, took off from Pago Pago, American Samoa, enroute Auckland, New Zealand. The airplane had a crew of seven, commanded by Captain Edwin C. Musick, the airline’s senior pilot, and a cargo of mail.

About two hours out, the number four engine began leaking oil. Captain Musick ordered the engine shut down. The flight radioed that they were returning to Pago Pago. They never arrived. Wreckage, a large oil slick, various documents and articles of the crew’s clothing were found by the U.S. Navy seaplane tender USS Avocet (AVP-4), 14 miles (22.5 kilometers) west of the island. It was apparent that the S-42 had exploded in mid-air.

The cause of the explosion is not known with certainty but based on Captain Musick’s handling of a similar problem with one of  Samoan Clipper‘s  engines on an earlier flight, a possible cause can be suggested.

Pan American Airways’ Samoan Clipper. (Hawaii Aviation)

On the earlier flight, the number four engine had begun seriously overheating and Musick ordered the flight engineer to shut it down. Because of the decreased power with only three engines, Captain Musick ordered the crew to begin dumping fuel to decrease the weight of the airplane before landing.

Pan American had tested the fuel dumping characteristics of the Sikorsky S-42 using dye, and had learned that because of the air flow patterns around the wings, the fluid tended to accumulate around the trailing edge of the wings and that it could actually be sucked into the wings themselves.

As fuel was being dumped on the previous flight, fuel vapors were present in the cabin, requiring all electrical systems to be shut off—even though it was night. Liquid gasoline was also dripping into the cockpit from the wing above.

Pan American Airways’ Sikorsky S-42B NC16734 at Pago Pago, 24 December 1937. (Unattributed)

Samoan Clipper had been very heavy with fuel when it departed for the long transoceanic flight to Auckland. Presuming that Captain Musick once again ordered fuel to be dumped prior to landing back at Pago Pago, and that the vapors collected around the wings, the fuel could have been detonated by the electrical motors which were used to lower the flaps for flight at slower speed, or by coming into contact with the hot exhaust of the engines.

Two independent investigations were carried out by Pan American and by the United States Navy, and both came to this conclusion.

Captain Edwin Charles Musick, Chief Pilot, Pan American Airways. (1894–1938)

There were no survivors of the explosion. Killed along with Captain Musick were Captain Cecil G. Sellers, Second Officer P.S. Brunk, Navigator F.J. MacLean, Flight Engineer J.W. Stickrod, Flight Mechanic J.A. Brooks and Radio Operator T.D. Findley.

The Sikorsky S-42B was a four-engine long-range flying boat built for Pan American Airways by the Vought-Sikorsky Aircraft Division of United Technologies at Stratford, Connecticut. It was 68 feet (20.726 meters) long with a wingspan of 118 feet, 2 inches (36.017 meters). The S-42 had an empty weight of 19,764 pounds ( kilograms) and gross weight of 38,000 pounds ( kilograms). It could carry up to 37 passengers.

The S-42B was powered by four air-cooled, supercharged, 1,690.537-cubic-inch-displacement (27.703 liters) Pratt & Whitney Hornet S1E-G nine-cylinder radial engines with a compression ratio of 6.5:1. The S1E-G had a Normal Power rating of 750 horsepower at 2,250 r.p.m., to 7,000 feet (2,134 meters), and 875 horsepower at 2,300 r.p.m., for Takeoff. The engines drove three-bladed Hamilton Standard constant-speed propellers through a 3:2 gear reduction. The S1E-G was 4 feet, 1.38 inches (1.254 meters) long, 4 feet, 6.44 inches (1.383 meters) in diameter, and weighed 1,064 pounds (483 kilograms).

The S-42B has a cruise speed 165 miles per hour (266 kilometers per hour) and maximum speed of 188 miles per hour (303 kilometers per hour) at 5,000 feet (1,524 meters). The service ceiling was 16,000 feet (4,877 meters), and it could maintain 7,500 feet (2,286 meters) with three engines. Its range was 1,930 miles (3,106 kilometers).

Boris Vasilievich Sergievsky. (Test & Research Pilots, Flight Test Engineers)

During flight testing of the S-42, Sikorsky test pilot Boris Vasilievich Sergievsky, with co-pilot Raymond B. Quick, set three Fédération Aéronautique Internationale world records for payload and altitude.¹  Later, Captain Musick, with Sergievsky and world-famous aviator Charles A. Lindbergh, flew the S-42 to set eight Fédération Aéronautique Internationale world records for speed.²

Ten Sikorsky S-42, S-42A and S-42B flying boats were built for Pan Am. None remain in existence.

Pan American Airways' Sikorsky S-42B NC16734, Samoan Clipper, moored at mechanic's Bay, Auckland, New Zealand, December 1937. The flying boat in the background is a Short S.23 Empire, G-ADUT, named Centaurus. (Turnbull Library)
Pan American Airways’ Sikorsky S-42B NC16734, Samoan Clipper, moored at Mechanic’s Bay, Auckland, New Zealand, December 1937. The flying boat in the background is a Short S.23 Empire, G-ADUT, named Centaurus. (Turnbull Library)

¹ 26 April 1934 FAI Record File Numbers: 11583: Greatest load to 2,000 meters (6,562 feet): 7,533 kilograms (16,652 pounds).  17 May 1934: 11582 and 11978: Altitude with a 5,000 Kilogram (11,023 pounds) Load, 6,220 meters (20,407 feet).

² 1 April 1934 FAI Record File Numbers: 11517: Speed over a closed circuit of 1,000 Kilometers (621.3 statute miles), 253,60 km/h (157.58 m.p.h.); 11518:  . . .  with a 500 Kilogram (1,102 pounds) Payload, 253,60 km/h (157.58 m.p.h.); 11519:  . . . with a 1,000 Kilogram (2,205 pounds) Payload, 253,60 km/h (157.58 m.p.h.);  11520: . . . with a 2,000 kilogram (4,409 pounds) Payload, 253,60 km/h (157.58 m.p.h.); 11521: Speed over a closed circuit of 2,000 Kilometers (1,242.7 statute miles), 253,18 km/h (157.32 m.p.h); 11522:  . . . with a 500 Kilogram Payload, 253,18 km/h (157.32 m.p.h.); 11523:  . . . with a 1,000 Kilogram Payload, 253,18 km/h (157.32 m.p.h.); 11524: . . . with a 2,000 Kilogram Payload, 253,18 km/h (157.32 m.p.h.).

© 2019, Bryan R. Swopes

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1 January 1914

SPT Airlines’ Benoist Type XIV flying boat takes off on the first scheduled commercial passenger flight, St. Petersburg, Florida, 1 January 1914. (State Archives of Florida, Florida Memory)
Antony H. Jannus, 1914

1 January 1914: The world’s first scheduled commercial passenger flight took place when Antony Habersack Jannus piloted a St. Petersburg–Tampa Airboat Line Benoist Type XIV flying boat from St. Petersburg to Tampa, Florida. The passenger was St. Petersburg’s mayor, Abraham C. Pheil. Over 3,000 people witnessed the departure.

The federal government determined that pilots of commercial flights should be licensed. Jannus became the first federally-licensed pilot.

SPT Airboat Lines was started by a local St. Petersburg businessman, Percival E. Fansler. Arrangements were made for the City of St. Petersburg to provide a $2,400 subsidy, payable at $40 per day, if SPT maintained a schedule of two flights per day, six days per week, for three months. Passenger tickets were priced at $5.00.

St. Petersburg-Tampa Airboat Line timetable. (Smithsonian Institution National Air and Space Museum)
St. Petersburg-Tampa Airboat Line timetable. (Smithsonian Institution National Air and Space Museum)
Thomas Wesley Benoist (State Historical Society of Missouri)

The Benoist Type XIV was a biplane designed by Thomas W. Benoist. The airplane was 26 feet (7.925 meters) long. The upper and lower wings both had a span of 44 feet (13.411 meters). Empty, the Type XIV weighed 1,250 pounds (567 kilograms).

Jannus’s Benoist was powered by a water-cooled, normally-aspirated, 477.129-cubic-inch-displacement (7.819 liter) Roberts Motor Company 1913 Model 6-X two-cycle inline six-cylinder engine which produced 66 horsepower at 1,000 r.p.m., and 75 horsepower at 1,225 r.p.m. It was a direct-drive engine which turned a 10-foot (3.048 meter) diameter two-bladed wooden propeller in a pusher configuration. The engine was 4 feet, 4.5 inches (1.334 meters) long,  2 feet, 1 inch (0.635 meters) high and 2 feet, 0 inch (0.610 meters) wide. It weighed 275 pounds (125 kilograms).

The airplane had a maximum speed of 64 miles per hour (103 kilometers per hour) and a range of 125 miles (201 kilometers).

Percival E. Fansler, Mayor Abraham C. Pheil, and Antony H. Jannus with the Benoist Type XIV flying boat Lark of Duluth, 1 January 1914. (Florida State Archives, Florida Memory)
Percival E. Fansler, Mayor Abraham C. Pheil, and Antony H. Jannus with the Benoist Type XIV flying boat Lark of Duluth, 1 January 1914. (State Archives of Florida, Florida Memory)

There were two Benoist Type XIVs, both purchased by the St. Petersburg Tampa Airboat Lines. They were named Lark of Duluth and Florida. Over the next three months, the two flying boats carried 1,205 passengers and flew over 11,000 miles (17,702 kilometers). When the city subsidy ceased, the airline was no longer profitable and the operation came to an end. Lark of Duluth was used to fly passengers at several cities around the United States, but was damaged beyond repair at San Diego, California.

Designer Thomas W. Benoist was killed in a trolley accident at Sandusky, Ohio, 14 June 1917.

Tony Jannus became a test pilot for Glenn Curtiss. In 1916 he was demonstrating a new Curtiss Model H flying boat in Russia, as well as training pilots. The airplane crashed into the Black Sea near Sevastopol. Jannus and two passengers were killed.


“Triumphant pilot Tony Jannus waves as he lands in Tampa on the first leg of that first regularly-scheduled airline flight in 1914.” (State Archives of Florida, Florida Memory.)

© 2018, Bryan R. Swopes

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22 November 1935

Pan American Airways’ Martin M-130 flying boat, China Clipper (NC14716), leaving the Golden Gate enroute to Honolulu, 22 November 1935. Photographed by Clyde Herwood Sunderland, Jr. (1900–1989).

22 November 1935: The Pan American Airways flying boat, China Clipper, a Martin M-130, NC14716, departed Alameda, California (an island in San Francisco Bay) at 3:46 p.m., Friday, and arrived at Honolulu at 10:39 a.m., Saturday, completing the first leg of a five-day trans-Pacific flight to Manila.

The aircraft commander was Captain Edwin Charles Musick, with First Officer Robert Oliver Daniel (“Rod”) Sullivan. The navigator was Frederick Joseph Noonan, who would later accompany Amelia Earhart on her around-the-world flight attempt. There were also a Second Officer and two Flight Engineers. The cargo consisted of 110,000 pieces of U.S. Mail.

Captain Edwin Musick and R.O.D. Sullivan, at the center of the image, next to the China Clipper before leaving San Francisco Bay with the first transpacific airmail, 22 November 1935. The three men at the right of the image are (left to right) Postmaster General James Farley; Assistant Postmaster General Harllee Branch; and Pan American Airways’ President Juan Trippe.

Pan Am personnel called the Clipper “Sweet Sixteen,” referring to its Civil Aeronautics Board registration number, NC14716. The airplane and Humphrey Bogart starred in a 1936 First National Pictures movie, “China Clipper.”

NC14716 was the first of three Martin M-130 four-engine flying boats built for Pan American Airways and was used to inaugurate the first commercial transpacific air service from San Francisco to Manila in November, 1935. Built at a cost of $417,000 by the Glenn L. Martin Company in Baltimore, Maryland, it was delivered to Pan Am on October 9, 1935. The airplane’s serial number was 558.

The M-130 was operated by a flight crew of 6–9, depending on the length of the flight, plus cabin staff, and could carry 18 passengers on overnight flights, or a maximum 36 passengers.

Cutaway illustration of Pan American Airways’ Martin M-130 China Clipper. Detail from larger image. (National Air and Space Museum SI-89-1216-A)
Martin M-130 3-view drawing. (Flight)

The Martin M-130 was 90 feet, 10.5 inches (27.699 meters) long with a wingspan of 130 feet, 0 inches (39.624 meters). It was 24 feet, 7 inches (7.493 meters) high. The total wing area was 2,315 square feet (215 square meters), including the “sea wings”. Its maximum takeoff weight was 52,252 pounds (23,701 kilograms).

The flying boat was powered by four air-cooled, supercharged Pratt & Whitney Twin Wasp S2A5-G two-row 14-cylinder radial engines with a compression ratio of 6.7:1.  They had a normal power rating 830 horsepower at 2,400 r.p.m., and 950 horsepower at 2,550 r.p.m. for takeoff. They drove three-bladed Hamilton Standard Hydromatic constant-speed propellers through a 3:2 gear reduction. The S2A5-G was 3 feet, 11.88 inches (1.216 meters) in diameter, 4 feet, 8.75 inches (1.441 meters) long, and weighed 1,235 pounds (560 kilograms).

Martin M-130 NC14716, right rear quarter view.

The airplane had a cruise speed of 130 miles per hour (209 kilometers per hour) and a maximum speed of 180 miles per hour (290 kilometers per hour). The M-130’s service ceiling was 10,000 feet (3,048 meters). Its range was 3,200 miles (5,150 kilometers).

Martin M-130, NC14716, China Clipper, moored at some distant exotic locale.
Martin M-130, NC14716, China Clipper, moored at some distant exotic locale. (Unattributed)

© 2018, Bryan R. Swopes

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3–4 November 1945

Boeing 314, California Clipper, NC18602, over Oakland, California, 1937. Photographed for Pan Am by Clyde Herwood Sunderland, Jr. (1900–1989).(Clyde Sunderland Photograph Collection, Library, University of California Berkeley)

3–4 November 1945: On the evening of Saturday, 3 November 1945, the Boeing 314 Honolulu Clipper, NC18601, departed Honolulu, Oahu, Territory of Hawaii, enroute to San Francisco, California. The flying boat was under the command of Captain Sanis E. (“Robby”) Robbins, Pan American Airways, with First Officer Wally Reed, Second Officer Dunbar Carpenter, Radio Officer Jack B. Crawford, First Engineer Dan W. Broadwater, Second Engineer Robert J. Dernberger. There were 13 passengers and 10 crew members on board. The flight to San Francisco was expected to take 11 hours.

Approximately 5 hours into the flight, the number 3 engine (starboard wing, inboard) began to backfire. It was shut down and the propeller feathered. Captain Robbins decided to return to Hawaii. A short while later, the number 4 engine (starboard wing, outboard) also started to malfunction. It continued to run but eventually it was also shut down.

With two engines inoperative, the airplane was unable to maintain altitude. At 11:07 p.m. local, Captain Robbins, in total darkness, brought the flying boat to a “masterful”  landing on the relatively calm surface of the Pacific Ocean. There were no injuries. The airplane suffered minor damage to the port sea wing, and started taking on water.

California Clipper, NC18602, another Boeing 314, also enroute to San Francisco, orbited Honolulu Clipper‘s position to guide rescue ships to scene. The following message was broadcast from Pearl Harbor:

PAN AMERICAN CLIPPER DOWN AT SEA AT 040935Z POSITION 2749N 14802W. PLANE IN GOOD CONDITION. IS ABLE TO COMMUNICATE ON [frequency deleted] KCS VOICECALL C18601 ON [frequency deleted] KCS. INVESTIGATE SIGHTINGS REPORT PERTINENT INFO TO ORIGINATOR.

Freighter S.S. John Henry Payne sighted flares fired from the flying boat and quickly arrived on scene. The ship took all of the passengers on board. Ten crew stayed aboard flying boat.

USS Manila Bay (CVE 61), a Casablanca-class escort aircraft carrier under the command of Captain Leon Johnson, was approximately 60 miles (97 kilometers) away, and had been ordered to take charge of efforts to salvage the airplane.

On arrival, a whale boat was sent to remove the remaining crew members from the flying boat. Wind and waves had increased and it was feared that the boat might damage the hull of the flying boat, so a rubber life raft was used to transfer the Clipper‘s crew to the whale boat. Aircraft mechanics were sent from Manila Bay to attempt to repair the airplane, but were not successful.

A whale boat from USS Manila Bay approaches Honolulu Clipper, 4 November 1945. (U.S. Navy)

Plans were made to rig the airplane for towing. 200 fathoms (1,200 feet/366 meters) of 6-inch (15.2 centimeter) diameter hawser was rigged from the aircraft carrier to the nose of the flying boat. Stabilizing lines were tied to the propeller hubs of the outboard engines. Manila Bay began towing the Honolulu Clipper and was gradually able to increase speed to 6 knots (7 miles per hour/11 kilometers per hour). About an hour after sunset, at about 7:30 p.m., the tow line parted.

Darkness and rising seas made it impossible to rig a new tow. Manila Bay stood by awaiting arrival of USS San Pablo (AVP-30) (Commander Charles Robert Eisenbach), a Barnegat-class seaplane tender, on Tuesday, 6 January, then departed for Pearl Harbor.

Seaplane tender USS San Pablo (AVP-30) standing by Honolulu Clipper. (U.S. Navy)
USS San Pablo approaches the undamaged Honolulu Clipper. (U.S. Navy)

During the several days that Honolulu Clipper was afloat in the open ocean, weather increased to the point that it was considered too hazardous to approach it in a small boat, so the aviation tender closed on the airplane directly to try to take it on tow. Unfortunately, San Pablo hit the clipper and caused significant damage.

Hawaii Clipper from the bridge of USS San Pablo. The starboard wing is damaged and the Number 4 engine is missing. (U.S. Navy)

With salvage impossible, the derelict Honolulu Clipper was now considered a hazard to navigation. It was sunk by 20 mm gun fire from San Pablo.

Honolulu Clipper was the prototype for the Boeing Model 314 series flyjng boat. It had been designed to carry a maximum of 76 passengers and a crew of 10 a distance of 5,200 miles at 184 miles per hour. The design used the wings and engine nacelles of Boeing’s experimental Model 294 (XB-15) very long-range heavy bomber.

The Boeing Model 314 was a large four-engine, high-wing monoplane flying boat designed and built by the Boeing Airplane Company to take off and land on water. It was 106 feet (32.309 meters) long with a wingspan of 152 feet (46.330 meters). It had a maximum take off weight of 82,500 pounds (37,421 kilograms).

Boeing 314 prototype NX18601 in original configuration. (Boeing Airplane Company)

The airplane was built at Boeing’s Plant 1, then transported by Barge to Elliot Bay. It carried experimental registration NX18601. Test pilot Edmund Turney (“Eddie”) Allen made the first flight of the prototype on 7 June 1938. He reported that the flying boat had insufficient rudder control and that he had to vary engine power to turn it. The prototype was modified to a twin-tail configuration.

Boeing Model 314 NX18601 flying over Elliot Bay. Note the twin-tail configuration. (Boeing Airplane Company)

With two vertical fins and rudders, control was improved, but was still insufficient. A third, center, fin was added and this became the production configuration.

Prototype Boeing 314 NX18601 in triple-tail configuration, 24 November 1938. (U.S. Air Force/San Diego Air and Space Museum)

The Boeing 314 was powered by four air-cooled, supercharged, 2,603.737-cubic-inch-displacement (42.668 liter) Wright Aeronautical Division Cyclone 14 GR2600A2, two-row, 14-cylinder radial engines with a compression ratio of 7.1:1. They were rated at 1,200 horsepower at 2,100 r.p.m., and 1,550 horsepower at 2,400 r.p.m. for takeoff, burning 91/96 octane gasoline. These engines (also commonly called “Twin Cyclone”) drove three-bladed Hamilton Standard Hydromatic full-feathering constant-speed propellers with a diameter of 14 feet (4.267 meters) through a 16:9 gear reduction. The GR2600A2 was 5 feet, 2.06 inches (1.576 meters) long and 4 feet, 7 inches (1.387 meters) in diameter. It weighed 1,935 pounds (878 kilograms). The engines could be serviced in flight, with access through the wings.

The Boeing 314 had a maximum speed of 199 miles per hour (320 kilometers per hour), with a range of 3,685 miles (5,930 kilometers) at its normal cruising speed of 183 miles per hour (295 kilometers per hour). Its service ceiling was 13,400 feet (4,084 meters). The fuel capacity was 4,246 gallons (16,073 liters).

Boeing built six Model 314 and another six 314A flying boats for Pan American Airways and British Overseas Airways Corporation. Pan Am paid $549,846.55 for each 314, about $9,545,726.07 in 2017 dollars, and Boeing lost money on every one sold.

Honolulu Clipper was leased to the United States Navy by Pan American Airways, 17 December 1942, and assigned Bureau of Aeronautics serial number (“Bu. No.”) 48227. The airplane continued to be operated by Pan Am crews.

A Pan American Airways Boeing 314 at Hawaii. (San Diego Air and Space Museum)

Sanis E. (“Robby”) Robbins was born at Matthews, Indiana, 17 September 1898. He was the sixth of seven children of William S. Robbins, a real estate agent, and Sarah Ellen Brokaw Robbins.

Robbins enlisted as a Private, United States Army, at Camp Dodge, Iowa, 26 June 1916. He was promoted to Private First Class on 1 August 1916, and to Corporal, 18 December 1916. Corporal Robbins was hospitalized at Brownsville, Texas, 4–23 January 1917. He was released from military service at Fort Des Moines, Iowa, 20 February 1917, shortly before the United States entered World War I. A 1920 Air Service Information Circular listed Second Lieutenant Sanis E. Robbins as a pursuit pilot, residing at Cassia, Florida.

Robby Robbins married Miss Virginia J. Bing. They would have three children.

Robbins was commissioned as a Lieutenant Commander, United States Naval Reserve, 15 September 1940. He held this rank until at least 1955.

Captain Sanis E. Robbins died at Palo Alto, California, 8 August 1961, at the age of 62 years. He was buried at the Golden Gate National Cemetery, San Bruno, California.

Pan American Airways Boeing 314 NC18604, Atlantic Clipper, taking off. (NASM)

© 2017, Bryan R. Swopes

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2 November 1947

Nov. 2, 1947: The Hughes Aircraft H-4 Hercules "Spruce Goose" during short flight in the Long Beach-Los Angeles Harbor. This photo was published in the Nov. 3, 1947 LA Times. (Los Angeles Times)
“Nov. 2, 1947: The Hughes Aircraft H-4 Hercules “Spruce Goose” during short flight in the Long Beach-Los Angeles Harbor. This photo was published in the Nov. 3, 1947 L.A. Times.” (Los Angeles Times)

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.

Hughes H-4 Hercules NX37602 in San Pedro Bay, 2 November 1947. Two U.S. Navy heavy cruisers and a fleet oiler are in the background. On the horizon is Santa Catalina Island, "Twenty-six miles across the sea...." (LIFE Magazine)
Hughes H-4 Hercules NX37602 in San Pedro Bay, 2 November 1947. Two U.S. Navy heavy cruisers and a fleet oiler are in the background. On the horizon is Santa Catalina Island. (LIFE Magazine)

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).

The flying boat was powered by eight air-cooled, supercharged 4,362.49-cubic-inch-displacement (71.489 liter) 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.

Howard Robard Hughes, Jr., in the cockpit of the H-4 Hercules, 6 November 1947. (J.R. Eyerman/LIFE Magazine)
Howard Robard Hughes, Jr., in the cockpit of the H-4 Hercules, 6 November 1947. (J.R. Eyerman/LIFE Magazine)

The airplane is on display at the Evergreen Aviation and Space Museum, McMinnville, Oregon.

© 2018, Bryan R. Swopes

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