All posts by Bryan Swopes

About Bryan Swopes

Bryan R. Swopes grew up in Southern California in the 1950s–60s, near the center of America's aerospace industry. He has had a life-long interest in aviation and space flight. Bryan is a retired commercial helicopter pilot and flight instructor.

13 December 1960

Lieutenant Henry L. (“Larry”) Monroe, USN, (left) and Commander Leroy Anthony Heath, USN, with a North American Aviation A3J-1 Vigilante, a carrier-based supersonic attack bomber. The two aviators are wearing B.F. Goodrich Mark IV full-pressure suits for protection at very high altitudes. (U.S. Navy)

13 December 1960: Commander Leroy Anthony Heath and Lieutenant Henry L. (“Larry”) Monroe, set a Fédération Aéronautique Internationale (FAI) World Record for Altitude¹ with an early production North American A3J-1 Vigilante supersonic attack bomber. A 1,000-kilogram payload was carried in the bomber’s tubular weapons bay.

Over Edwards Air Force Base, in the high desert of southern California, the Vigilante accelerated to approximately 1,400 miles per hour (2,253 kilometers per hour), then pulled up into a steep climb. The Vigilante zoom-climbed in a nearly ballistic trajectory and reached an altitude of 27,874 meters (91,450 feet).¹ As the aircraft went “over the top,” it had slowed to about 400 miles per hour (644 kilometers per hour). They were momentarily “weightless,” which Commander Heath described as a “pleasant sensation.”

Their new record broke the previous record by 7,418 meters (24,337 feet).²

According to an article by Greg Goebel on the web site Air Vectors,

“. . . At that altitude, the aircraft was no longer aerodynamic and tumbled onto its back as it fell down the far side of the arc, with the engines flaming out in the thin atmosphere. However, such problems had been encountered in practice flights leading up to the attempt, and the flight crew knew what to expect. Heath simply neutralized the controls; once the Vigilante reached thicker air halfway through its fall, it naturally adopted a nose-down attitude, and Heath was able to relight the engines.”

— http://www.airvectors.net/ava5.html

North American Aviation A3J Vigilante. (SDASM Archives Catalog #: 00001959)

For their achievement, the Secretary of the Navy, William B. Franke, awarded Commander Heath the Distinguished Flying Cross, and Lieutenant Monroe, the Air Medal. Also present at the 16 December 1960 presentation were Admiral Arleigh Burke, Chief of Naval Operations, and Admiral James Russell, Vice Chief of Naval Operations.

Lieutenant Larry Monroe and Commander Leroy Heath in the cockpits of a North American Aviation A3J-1 Vigilante supersonic attack bomber. (Detail & Scale)

Navy Jet Breaks Russ World Altitude Mark

Vigilante Attack Bomber Carries More Thank 2,000 Lb. Payload to 91,450.8 Ft.

     A Navy Vigilante attack bomber has carried a payload of more than 2,000 lb. to an altitude of 91,045.8 ft. to break Russia’s international record of 67,096 ft., it was disclosed Thursday.

The flight was made last Tuesday from Edwards Air Force Base by a North American twin-jet A3J aircraft piloted by Comdr. Leroy A. Heath of the Naval Air Test Center, Patuxent, Md.

     It was observed officially by representatives of the National Aeronautic Assn. headed by Bertrand Rhine, chief West Coast timer.

     A U.S. claim for a world record altitude for a land-based jet aircraft carrying a 1,000 kilogram (2,204.62 lbs.) payload has been filed with the Federation Aeronautique Internationale, world record agency in Paris.

Awarded Medal

     Comdr. Heath was awarded the Distinguished Flying Cross for the record achievement. His navigator, Lt. Larry Monroe, was awarded the Air Medal. The presentations were made in Washington Thursday by Navy Secretary Franke.

     Following a carefully controlled flight pattern, the Vigilante’s high climb was tracked by altitude registering radars monitored by NAA representatives on the ground. The record altitude also was calibrated by a sealed barograph carried in the plane to measure and record air pressures from which height can be determined.

     The flight marked the first time the United States has competed for this particular class record which requires that the aircraft carry its payload in a compartment measuring at least 141 cubic ft.

     The Vigilante is a double sonic, all-weather attack plane built by North American Aviation’s Colombus (O.) division. Designed for carrier operation, it can deliver both nuclear and conventional weapons by a unique tail ejection system from very high altitude or on deck-level attack missions.

     Powered by two General Electric J79 engines developing approximately 15,000 lbs. of thrust each, the Vigilante is 70 ft. long and has a wing span of 50 ft.

     The previous Russian record was set July 13, 1959, by Vladimir Smirnov, flying a twin-jet RVmonoplane over Bykova Aerodrome near Moscow.

Los Angeles Times, 16 December 1960, Page 2, Column 6, and Page 32, Column 2.

The prototype North American Aviation YA3J-1 Vigilante. (Boeing)

The North American Aviation A3J-1 Vigilante is a carrier-based, twin-engine, supersonic bomber designed for high-altitude nuclear attacks. It is crewed by a pilot and navigator. The airplane has a high-mounted swept wing and tricycle landing gear. There are no ailerons, elevators or rudder. Control is provided by spoilers, a large moveable vertical fin and independent horizontal stabilizers.

The A3J-1 is 76.547 feet (23.332 meters) long with a wing span of 53.02 feet (16.16 meters), and overall height of 19.366 feet (5.90 meters). The wings are swept 37.5° at 25% chord. The wing area is 700 square feet (65 square meters). The bomber has an empty weight of 32,714 pounds (14,839 kilograms) and Maximum Takeoff Weight (MTOW) of 56,293 pounds (25,534 kilograms).

Three-view illustration with dimensions. (U.S. Navy)

The A3J-1 Vigilante is powered by two General Electric J79-GE-8  turbojet engines with afterburner. The J79 is a single-spool axial-flow turbojet with a 17 stage compressor and 3-stage turbine. It is 17 feet, 4.inches (5.625 meters) long, with a diameter of 2 feet, 7.6 inches (0.803 meters). The J79-GE-8 produced a maximum 17,000 pounds of thrust (23.049 kilonewtons) at 7,685 r.p.m.

A North American Aviation A3J-1 Vigilante,  circa 1958. (U.S. Navy 1039888)

The A3J-1 had a maximum speed of 1,147 knots (1,320 miles per hour/2,124 kilometers per hour) at 40,000 feet (12,192 meters). Its combat ceiling was 52,100 feet (15,880 meters).

The Vigilante had a tubular bomb bay between the engines. Weapons were ejected rearward. It could carry a Mk 28, Mk 27 or Mk 43 thermonuclear bomb in the weapons bay, or conventional or nuclear bombs mounted on underwing hardpoints. The A3J carried no defensive weapons.

In 1962, the A3J was designated as A-5. North American Aviation built a total of 167 Vigilantes, in both attack and reconnaissance (RA-5C) variants.

The nuclear-powered aircraft carrier USS Enterprise (CVAN-65) launches a North American Aviation A3J Vigilante from a forward catapult. (U.S. Navy)

Leroy Anthony Heath was born in Detroit, Michigan, 20 November 1922. He was the first of seven children of Leroy Vincent Heath, a firefighter, and Catherine Crumley Heath. He graduated from high school in 1941 then went to work for the Cadillac Motor Car Division, General Motors Corporation.

Heath enlisted in the United States Navy 7 August 1942. He had brown hair and eyes, a light complexion, was 6 feet (1.83 meters) tall and weighing 190 pounds (86 kilograms), he was selected as an aviation cadet through the V-5 Program, 3 January 1943. After completion of flight training, on 1 July 1944 Aviation Cadet Heath was designated a Naval Aviator and commissioned as an ensign, United States Naval Reserve (U.S.N.R.). Sent to the Pacific Theater, Ensign Heath flew Chance Vought F4U Corsairs from USS Lexington (CV-16). Following the end of World War II, Heath was transferred to the Regular Navy (U.S.N.). He was promoted to the rank of lieutenant, junior grade, 1 January 1946.

On 9 November 1946, Lieutenant (j.g.) Heath married his long-time girlfriend, Miss Mary Helen Garver in Detroit. They would have seven children.

Heath graduated with Class 9 of the U.S. Navy’s test pilot school at NAS Patuxent River, Maryland. He served two tours as a project officer in the Service Test Division at the Naval Air Test Center.

He was promoted to lieutenant, 5 July 1951, and to lieutenant commander, 1 November 1955.

CDR Leroy A. Heath, USN, commanding officer, Heavy Attack Squadron SEVEN (VAH-7), USS Enterprise (CVAN 65), 1963. (U.S. Navy)

In 1962, Commander Heath as commanding officer of VAH-7, a heavy attack squadron, flying the new A3J-1 Vigilante from USS Enterprise (CVAN-65). He later served as operations officer of USS Independence (CVA-62).

On 1 January 1965, Heath was promoted to the rank of captain. From September 1968 to December 1969, he was in command of the attack transport, USS Cambria (APA-36). (Naval aviators were often assigned as commanding officers of “deep draft” ships prior to serving as captain of an aircraft carrier.)

USS Cambria (APA-36), at Valetta, Malta, 1968. Capatin Heath commanded the attack transport 25 Sept 1968–December 1969. (U.S. Navy)

After a tour as Executive Director, Material Acquisitions Group, Naval Air Systems Command, Captain Heath retired from the U.S. Navy in March 1972.

After earning a bachelor’s and masters degree in education from the University of Central Florida, Heath served as an assistant professor of mathematics at the Embry-Riddle Aeronautical University, 1976 through 1985.

Mary Helen Heath died 28 Oct 1985. Professor Heath then married his second wife, Ms. Tamara Sue Sundbo, 20 June 1987 at Volusia, Florida.

Captain Heath died 21 February 2003.

¹ FAI Record File Number 4568

² FAI Record File Number 14658: Vladimir Smirnov, 13 July 1959. Air craft RV w/ 37V engine

© 2021, Bryan R. Swopes

13 December 1958

NASA test pilot Einar K. Enevoldson in the cockpit of a NASA/Lockheed F-104N, N811NA, in 1984. (NASA)
NASA test pilot Einar K. Enevoldson in the cockpit of a NASA/Lockheed F-104N, N811NA, in 1984. (NASA)

13 December 1958: First Lieutenant Einar Knute Enevoldson, U.S. Air Force, set seven Fédération Aéronautique Internationale (FAI) time-to-climb records in a Lockheed F-104A-10-LO Starfighter, serial number 56-762,¹ at Naval Air Station Point Mugu (NTD) (located on the shore of southern California), including Sea Level to 3,000 meters (9,843 feet) in 41.85 seconds; 6,000 meters (19,685 feet) in 58.41 seconds; 9,000 meters (29,528 feet) in 1 minute, 21.14 seconds; 12,000 meters (39,370 feet) in 1 minute, 39.90 seconds; 15,000 meters (49,213 feet) in 2 minutes, 11.1 seconds; 20,000 meters (65,617 feet) in 3 minutes, 42.99 seconds; and 25,000 meters (82,021 feet) in 4 minutes, 26.03 seconds.

Lockheed F-104A Starfighter 56-762 being prepared for a record attempt at NAS Point Mugu. (F-104 Society)
Lockheed F-104A-10-LO Starfighter 56-762 being prepared for a record attempt at NAS Point Mugu, California. (International F-104 Society)

Lieutenant Enevoldson was awarded the Distinguished Flying Cross for these accomplishments.

The Distinguished Flying Cross
The Distinguished Flying Cross

FAI Record File Num #9107 [Direct Link]
Status: ratified – retired by changes of the sporting code
Region: World
Class: C (Powered Aeroplanes)
Sub-Class: C-1 (Landplanes)
Category: Not applicable
Group: 3 : turbo-jet
Type of record: Time to climb to a height of 3 000 m
Performance: 41.85s
Date: 1958-12-13
Course/Location: Point Mugu, CA (USA)
Claimant Einar Enevoldson (USA)
Aeroplane: Lockheed F-104A “Starfighter”
Engine: 1 G E J79

FAI Record File Num #9106 [Direct Link]
Status: ratified – retired by changes of the sporting code
Region: World
Class: C (Powered Aeroplanes)
Sub-Class: C-1 (Landplanes)
Category: Not applicable
Group: 3 : turbo-jet
Type of record: Time to climb to a height of 6 000 m
Performance: 58.41s
Date: 1958-12-13
Course/Location: Point Mugu, CA (USA)
Claimant Einar Enevoldson (USA)
Aeroplane: Lockheed F-104A “Starfighter”
Engine: 1 G E J79

FAI Record File Num #9105 [Direct Link]
Status: ratified – retired by changes of the sporting code
Region: World
Class: C (Powered Aeroplanes)
Sub-Class: C-1 (Landplanes)
Category: Not applicable
Group: 3 : turbo-jet
Type of record: Time to climb to a height of 9 000 m
Performance: 1 min 21.14s
Date: 1958-12-13
Course/Location: Point Mugu, CA (USA)
Claimant Einar Enevoldson (USA)
Aeroplane: Lockheed F-104A “Starfighter”
Engine: 1 G E J79

FAI Record File Num #9104 [Direct Link]
Status: ratified – retired by changes of the sporting code
Region: World
Class: C (Powered Aeroplanes)
Sub-Class: C-1 (Landplanes)
Category: Not applicable
Group: 3 : turbo-jet
Type of record: Time to climb to a height of 12 000 m
Performance: 1 min 39.90s
Date: 1958-12-13
Course/Location: Point Mugu, CA (USA)
Claimant Einar Enevoldson (USA)
Aeroplane: Lockheed F-104A “Starfighter”
Engine: 1 G E J79

FAI Record File Num #9103 [Direct Link]
Status: ratified – retired by changes of the sporting code
Region: World
Class: C (Powered Aeroplanes)
Sub-Class: C-1 (Landplanes)
Category: Not applicable
Group: 3 : turbo-jet
Type of record: Time to climb to a height of 15 000 m
Performance: 2 min 11.1s
Date: 1958-12-13
Course/Location: Point Mugu, CA (USA)
Claimant Einar Enevoldson (USA)
Aeroplane: Lockheed F-104A “Starfighter”
Engine: 1 G E J79

FAI Record File Num #9102 [Direct Link]
Status: ratified – retired by changes of the sporting code
Region: World
Class: C (Powered Aeroplanes)
Sub-Class: C-1 (Landplanes)
Category: Not applicable
Group: 3 : turbo-jet
Type of record: Time to climb to a height of 20 000 m
Performance: 3 min 42.99s
Date: 1958-12-13
Course/Location: Point Mugu, CA (USA)
Claimant Einar Enevoldson (USA)
Aeroplane: Lockheed F-104A “Starfighter”
Engine: 1 G E J79

FAI Record File Num #9080 [Direct Link]
Status: ratified – retired by changes of the sporting code
Region: World
Class: C (Powered Aeroplanes)
Sub-Class: C-1 (Landplanes)
Category: Not applicable
Group: 3 : turbo-jet
Type of record: Time to climb to a height of 25 000 m
Performance: 4 min 26.03s
Date: 1958-12-13
Course/Location: Point Mugu, CA (USA)
Claimant Einar Enevoldson (USA)
Aeroplane: Lockheed F-104A “Starfighter”
Engine: 1 G E J79

U.S. Air Force Lockheed F-104A-10-LO Starfighter 56-762 on the runaway at Naval Air Station Point Mugu, December 1958. (International F-104 Society)
U.S. Air Force Lockheed F-104A-10-LO Starfighter 56-762 on the runaway at Naval Air Station Point Mugu, December 1958. (International F-104 Society)

Einar Enevoldson later flew as a civilian test pilot for NASA from 1968 to 1986 and was awarded the NASA Exceptional Service Medal. He holds numerous FAI world records.

Lockheed F-104A-10-LO Starfighter 56-762 climbing under Southern California's overcast coastal skies. (International F-104 Society)
Lockheed F-104A-10-LO Starfighter 56-762 climbing under Southern California’s overcast coastal skies. (International F-104 Society)

The Lockheed F-104A Starfighter was a single-place, single-engine supersonic interceptor. It was designed by a team lead by the legendary Clarence L. “Kelly” Johnson. The F-104A was 54 feet, 8 inches (16.662 meters) long with a wingspan of 21 feet, 9 inches (6.629 meters) and overall height of 13 feet, 5 inches (4.089 meters). It had an empty weight of 13,184 pounds (5,980.2 kilograms), combat weight of 17,988 pounds (8,159.2 kilograms), gross weight of 22,614 pounds (10,257.5 kilograms) and a maximum takeoff weight of 25,840 pounds (11,720.8 kilograms). Internal fuel capacity was 897 gallons (3,395.5 liters).

The F-104A was powered by a single General Electric J79-GE-3A engine, a single-spool axial-flow afterburning turbojet, which used a 17-stage compressor and 3-stage turbine. The J79-GE-3A is rated at 9,600 pounds of thrust (42.70 kilonewtons), and 15,000 pounds (66.72 kilonewtons) with afterburner. The engine is 17 feet, 3.5 inches (5.271 meters) long, 3 feet, 2.3 inches (0.973 meters) in diameter, and weighs 3,325 pounds (1,508 kilograms).

The F-104A had a maximum speed of 1,037 miles per hour (1,669 kilometers per hour) at 50,000 feet (15,240 meters). Its stall speed was 198 miles per hour (319 kilometers per hour). The Starfighter’s initial rate of climb was 60,395 feet per minute (306.8 meters per second) and its service ceiling was 64,795 feet (19,750 meters).

Armament was one General Electric M61 Vulcan six-barreled revolving cannon with 725 rounds of 20 mm ammunition. An AIM-9B Sidewinder heat-seeking air-to-air missile could be carried on each wing tip, or a jettisonable fuel tank with a capacity of 141.5 gallons (535.6 liters).

Lockheed built 153 of the F-104A Starfighter initial production version. A total of 2,578 F-104s of all variants were produced by Lockheed and its licensees, Canadair, Fiat, Fokker, MBB, Messerschmitt,  Mitsubishi and SABCA. By 1969, the F-104A had been retired from service. The last Starfighter, an Aeritalia-built F-104S ASA/M of the  Aeronautica Militare Italiana, was retired in October 2004.

The same type aircraft as that flown by Einar K. Enevoldson, this is a Lockheed F-104A-10-LO Starfighter, 56-761. It is carrying both wingtip and underwing fuel tanks. (U.S. Air Force)
The same type aircraft as that flown by Einar K. Enevoldson, this is a Lockheed F-104A-10-LO Starfighter, 56-761. It is carrying both wingtip and underwing fuel tanks. (U.S. Air Force)

¹ 56-762 was one of three F-104As later converted to an NF-104A rocket/turbojet Advanced Aerospace Trainer. It is the same Starfighter that crashed when Chuck Yeager had to eject after it went into an uncontrolled spin during a zoom-climb altitude record attempt, 10 December 1963.

© 2016, Bryan R. Swopes

13 December 1955

DH.106 Comet 3 G-ANLO is decorated with a flower lei on its arrival at Honolulu International Airport, 13 December 1955. (Zoggavia)
De Havilland DH.106 Comet 3 G-ANLO is decorated with a flower lei on its arrival at Honolulu International Airport, 13 December 1955. (Zoggavia)

13 December 1955: The first landing of a commercial jet airliner on United States territory took place when a de Havilland DH.106 Comet 3, G-ANLO, flown by de Havilland’s chief test pilot, John Cunningham, with co-pilot Per Buggé, arrived at Honolulu International Airport, on the Island of Oahu, Territory of Hawaii.

The Comet 3 was on an around-the-world tour. The 3,212 mile (5,169 kilometer) flight from Nadi, Fiji (NAN) to Honolulu (HNL) took 6 hours, 41 minutes. The Comet remained at Hawaii for two days and gave a series of demonstration flights before continuing on its journey. The next leg, to Vancouver, British Columbia, Canada, a distance of 2,771 miles (4,460 kilometers), took 5 hours, 40 minutes.

De Havilland DH.106 Comet 3 G-ANLO ay the Farnborough Airshow, September 1954. (RuthAS via Wikipedia)
De Havilland DH.106 Comet 3 G-ANLO at the Farnborough Airshow, September 1954. (RuthAS via Wikipedia)

The de Havilland DH.106 Comet 3 was a further development of the Comet 2 series. It was 15 feet (4.572 meters) longer with a length of 111 feet, 6 inches (33.985 meters), a wingspan of 115 feet (35.052 meters) and overall height of 29 feet, 6 inches (8.992. The area of the wings and tail surfaces had been increased. It was powered by four Rolls Royce Avon 521 turbojet engines, rated at 10,000 pounds of thrust, each.

The airliner was designed to carry 58–76 passengers on flights ranging to 2,600 miles (4,184 kilometers). In addition to the increased length, visual differences from the previous Comets were the circular passenger windows, and wing tanks extending forward from the wings’ leading edges.

De Havilland DH.106 Comet 3 G-ANLO, left quarter, at Entebbe Airport, Uganda, 1955. (Dphne Seager)
De Havilland DH.106 Comet 3 G-ANLO, left quarter, at Entebbe Airport, Uganda, 1955. (Daphne Seager)

Only two Comet 3s were built and one was used as a static test article. Production continued with the Comet 4, which had even greater improvements. G-ANLO remained a development prototype and was modified several times. It was turned over to the Ministry of Supply and re-registered XP915. The airplane was used in instrument landing tests and later converted to a mockup of the Hawker Siddeley Nimrod MR1 maritime patrol aircraft. It was taken out of service in 1973.

Group Captain John Cunningham C.B.E., D.S.O. and Two Bars, D.F.C. and Bar, A.E., was the highest scoring Royal Air Force night fighter pilot of World War II, credited with shooting down 20 enemy airplanes. He was responsible for the myth that eating carrots would improve night vision.

Group Captain John Cunningham, Royal Air Force. (Daily Mail)
Group Captain John Cunningham, Royal Air Force, 1917–2002. (Daily Mail)

© 2015, Bryan R. Swopes

13 December 1951

Major George Andrew Davis, Jr., United states Air Force, 334th Fighter Interceptor Squadron, 4th Fighter Interceptor Wing, Korea, 1951. (U.S. Air Force)
Major George Andrew Davis, Jr., United States Air Force, Commanding Officer, 334th Fighter Interceptor Squadron, 4th Fighter Interceptor Wing, Korea, 1951. (U.S. Air Force)

13 December 1951: Major George Andrew Davis, Jr., United States Air Force, commanding officer of the 334th Fighter Interceptor Squadron, 4th Fighter Interceptor Wing, flying a North American F-86E-10-NA Sabre, serial number 51-2752, led his unit on two “MiG Sweeps.”

Film from the gun camera of Major Davis’ F-86E Sabre 51-2752 shows a MiG 15 smoking after being hit, 13 December 1951. (U.S. Air Force)
Film from the gun camera of Major Davis’ F-86E Sabre 51-2752 shows a MiG 15 smoking after being hit, 13 December 1951. (U.S. Air Force)

During the mid-day fighter sweep, the 334th encountered Mikoyan Gurevich MiG 15 fighters of the 18th GIAP, 303rd IAD,  Voyenno-Vozdushnye Sily (the Soviet Air Force), and an air battle ensued. Major Davis was credited with shooting down two of the Russian fighters. The pilot of one of the MiGs, I.A. Gorsky, was killed. The identity and fate of the second Soviet pilot is not known.

During a second sweep in mid-afternoon, George Davis and the 334th again encountered enemy MiG 15s of the 40th Regiment, 14th Division, of the Peoples Liberation Army Air Force (Chinese Air Force). At 3:52 p.m. (1352) Davis shot down one of the Chinese MiG 15s. One minute later, he shot down another, his fourth aerial victory for the day.

These frames of film from the gun camera of Davis’ F-86 Sabre show a MiG 15 trailing smoke after being hit by the Sabre’s six .50-caliber machine guns. Chinese sources confirmed the loss of two MiG 15s, but again, the identities of the pilots and whether or not they survived is not known.

This North American Aviation F-86E-10-NA Sabre, 51-2849, seen here in flight over Edwards Air Force base, california, is the same type fighter that was flown by Major George Davis, 13 December 1951. (U.S. Air Force)
This North American Aviation F-86E-10-NA Sabre, 51-2849, seen here in flight near Edwards Air Force Base, California, is the same type fighter that was flown by Major George A. Davis, Jr., 13 December 1951. (U.S. Air Force)

© 2015, Bryan R. Swopes

13 December 1937

Jackie Cochran with the Seversky “SEV-S1 Executive,” X18Y, 1937. (Cliff Henderson Collection, San Diego Air & Space Museum Archives, Catalog #: CF_09-0043)

On 9 December Jackie Cochran flew the Seversky SEV-S1 Executive, X18Y, to a new U.S. national record speed of 252.875 miles per hour (406.963 kilometers per hour) over a 100-kilometer course. She was attempting to increase her speed on 13 December, reaching an average 255.973 miles per hour (411.949 kilometers per hour).

When Jackie landed at Miami after the record runs, the Seversky’s tail wheel began rapidly swinging from side to side. This was something that the P-35s were experiencing and a number of the fighters had been wrecked. Jackie said, “One wing was pulled off altogether and the landing gear was torn off,” she said. “The tail [wheel] had jumped its lock throwing the plane to one side.”

The SEV-S1 was damaged beyond economical repair. In less than three years it had served its purpose. Seversky would build a new airplane. X18Y’s registration was suspended 4 January 1938 and the airplane was scrapped.

Seversky SEV-S1 R18Y, after landing accident, Miami, Florida, 13 December 1937. (Los Angeles Times, Vol. LVII, Tuesday, 14 December 1937, Page 20)

The SEV-S1 was a civil variant of Major de Seversky’s P-35A fighter, which was the U.S. Army Air Corps’ first all-metal, single-engine airplane with an enclosed cockpit and retractable landing gear.

The Seversky SEV-2XP X18Y in the two-place, fixed landing gear configuration with fixed landing gear. (Ray Wagner Collection, San Diego Air & Space Museum Archives, Catalog #: 16_006753)

Designed by Alexander Kartvelishvili, the airplane had originally been built as the Seversky II X, a single-place open cockpit monoplane with fixed landing gear. It was powered by an air-cooled, supercharged 1,666.860-cubic-inch-displacement (27.315 liter) Wright Aeronautical Division GR1670A1 Whirlwind, a two-row, 14-cylinder radial engine. The GR1670A1 had a compression ratio of 6.75:1 and was rated at 775 horsepower at 2,400 r.p.m., and 830 horsepower at 2,400 r.p.m. for takeoff, using 87-octane aviation gasoline. It drove an experimental three-bladed Hamilton Standard constant-speed propeller through a 16:11 gear reduction. The GR1670A1 was 45 inches (1.143 meters) in diameter, 52-25/32 inches (1.341 meters) long, and weighed 1,160 pounds (526 kilograms).

The Seversky II X was reconfigured as two-place monoplane fighter to compete in a fly-off at Wright Field against the Curtiss-Wright Model 75 Hawk and the Northrop 3A for the Air Corps fighter contract in 1935. The airplane was redesignated SEV-2XP and carried the registration mark X18Y.

The Curtiss-Wright Model 75, X17Y. This prototype would be developed into the P-36 Hawk and later, the P-40 Warhawk. (Ray Wagner Collection, San Diego Air & Space Museum Archives, Catalog #: 16_008032)
The Northrop 3A, photographed 30 July 1935, the day it disappeared off the coast of southern California. No trace was found of it or the pilot, 1st Lieutenant Arthur Henry Skaer, Jr. (Ray Wagner Collection, San Diego Air & Space Museum Archives, Catalog #: 16_005638)

In mid May 1935, de Seversky was flying the prototype from the company’s Farmingdale, New York factory toward Wright Field, located near Dayton, Ohio. The airplane’s engine overheated and stopped. He made a forced landing at a small hilltop landing field near St. Clairsville, Ohio, during which the airplane was damaged. Several weeks were required to make repairs.

In the meantime, de Seversky had seen his competitors’ entries. Both were single place pursuits with retractable landing gear. He realized that his -2XP was completely outclassed.

The prototype was once again rebuilt. It was now also a single-place airplane with retractable landing gear. Designated SEV-1XP, X18Y was initially powered by a 1,823.129 cubic inch displacement (29.876 liters) 860-horsepower Wright Cyclone, which was quickly upgraded to a Wright GR-1820G4. This was also a single-row, nine-cylinder radial engine. The G4 had a compression ratio of 6.45:1 and required 87-octane aviation gasoline. It was rated at 810 horsepower at 2,100 r.p.m., and 1,000 horsepower at 2,200 r.p.m.for takeoff. The engine was 47¾ inches (1.213 meters) long, 54¼ inches in diameter, and weighed 1,210 pounds (549 kilograms). The SEV-1XP had a fuel capacity of 160 U.S. gallons (606 liters) and carried 15 gallons (57 liters) of lubricating oil.

Seversky SEV-1XP X18Y. (Seversky Aircraft Company)
Seversky SEV-1XP X18Y (Ray Wagner Collection, San Diego Air & Space Museum Archives, Catalog #: 16_006757)

In April 1936, X18Y’s engine was once again upgraded, this time to a Wright GR-1820G5, s/n 23233.

Major Alexander de Seversky with SEV-1XP X18Y. (Ray Wagner Collection, San Diego Air & Space Museum Archives, Catalog #16_006759)

Another engine change came in January 1937. The Wright Cyclone was replaced by a Pratt & Whitney Twin Wasp R-1830-13, s/n 312. With the Twin Wasp, NR18Y’s designation was changed to SEV-S1. (Department of Commerce records continued to refer to it as SEV-1XP.) The -13 was a supercharged, two row, fourteen cylinder radial engine with a compression ratio of 6.7:1, requiring 91/93-octane aviation gasoline. It had a normal power rating of 900 horsepower at 2,550 r.p.m., to an altitude of 10,000 feet (3,048 meters), and 1,050 horsepower at 2,700 r,p,m for takeoff. The airplane retained the same Hamilton Standard propeller that had been used with the R-1820G5, which it drove through a 3:2 gear reduction. The R-1830-13 was 48.06 inches (1.221 meters) long, 59.25 inches (1.505 meters) in diameter, and weighed 1,370 pounds (621 kilograms).

In August 1937, the R-1830-13 was replaced by a R-1830 SB-G, s/n 112. Again, the same propeller was used. The SB-G had a normal rating of 900 horsepower at 2,450 r.p.m., to 6,500 feet (1,981 meters), and 1,000 horsepower at 2,600 r.p.m. for takeoff. 87-octane fuel was required. The SB-G had the same gear reduction ratio as the -13. It was 48.00 inches (1.219 meters) long, 55.48 inches (1.409 meters) in diameter, and weighed 1,284 pounds (582 kilograms).

On 30 August 1937, the Seversky SEV-1XP was issued a restricted registration, R18Y. As it was then configured, it had an actual empty weight of 4,390 pounds (1,991 kilograms) and gross weight of 6,290 pounds (2,853 kilograms).

Frank Sinclair, Seversky’s chief test pilot, flew R18Y in the 1937 National Air Races, held at Columbus, Ohio. Sinclair’s race number, 63, was painted on the vertical fin. On 4 September, he finished the Bendix Trophy Race from Burbank, California, to Columbus, in fourth place with a time of 11 hours, 2 minutes, winning a $2,000 prize. (Jackie Cochran flew a Beech Staggerwing in the Bendix, beating Sinclair and R18Y by 33 minutes.) Two days later, 6 September, Sinclair placed fourth in the Thompson Trophy pylon race. The Seversky averaged 252.360 miles per hour (406.134 kilometers per hour).

On 27 October 1937, the Seversky’s registration reverted to X18Y.

The Seversky’s passenger compartment was accessed through a hatch on the right side of the fuselage. (San Diego Air and Space Museum Archives)

Following an accident at Miami, 13 December 1937, the Department of Commerce suspended X18Y’s registration, noting “AIRCRAFT NOT APPROVED FOR RELICENSING”

It is believed that the prototype was scrapped.

¹ At that time, experimental and restricted category aircraft were prohibited from displaying the letter “N” at the beginning of their registration mark.

© 2021, Bryan R. Swopes