Tag Archives: Test Pilot

26 October 1940

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North American Aviation NA-73X prototype, left front quarter view. (North American Aviation, Inc.)

26 October 1940: At Mines Field, Los Angeles, California (now, Los Angeles International Airport), free lance test pilot Vance Breese took the prototype North American Aviation NA-73X, civil registration NX19998, on a five-minute first flight. Later in the day, Breese flew the NA-73X another ten minutes. He would make six more test flights between 26 October and 13 November, totaling approximately 3 hours, 30 minutes of flight time.

With Great Britain at war with Nazi Germany, the Royal Air Force was the primary defender of the island nation. Airplane manufacturers were turning out Hawker Hurricanes and Supermarine Spitfires as rapidly as possible, but they were barely keeping up with combat losses. England needed more fighters. They had taken over an order for Curtiss-Wright Hawk 81-A1 fighters which had been built for France, but which had not been shipped by the time France surrendered. The RAF called these fighters the Tomahawk Mark I (P-40 Warhawk in U.S. service).

North American Aviation’s NA-73X fighter prototype, engine idling, with Vance Breese in the cockpit at Mines Field, Los Angeles, 26 October 1941. (North American Aviation Inc.)

The British Purchasing Commission asked North American Aviation in Los Angeles, California, to build additional Tomahawks under license from Curtiss-Wright. North American countered with a proposal to design a completely new and superior fighter around the P-40’s Allison V-12 engine, and begin production in no more time than it would take to get a P-40 production line up and running. The Purchasing Commission agreed, and with a letter of understanding, North American began work on the NA-73X on 1 May 1940. They were to produce 320 fighters before 30 September 1941, approximately 50 per month, at a total price of $14,746,964.35.

Vance Breese in the cockpit of the NA-73X, NX19998, at Mines Field, preparing for a test flight. (North American Aviation)

In a contract amendment dated 9 December 1940, the British Purchasing Commission directed that the NA-73 would be identified by the name, “Mustang.”

The prototype NA-73X, North American serial number 73-3097, was a single-seat, single-engine, low wing monoplane with retractable landing gear. It was primarily of metal construction, though the flight control surfaces were fabric covered. The airplane was designed for the maximum reduction in aerodynamic drag. The fuselage panels were precisely designed and very smooth. Flush riveting was used. The Mustang was the first airplane to use a laminar-flow wing. The coolant radiator with its intake and exhaust ducts was located behind and below the cockpit. As cooling air passed through the radiator, it was heated and expanded, so that as it exited, it actually produced some thrust.

The prototype was 32 feet, 2–5/8 inches (9.820 meters) long, with a wing span of 37 feet, 5/16 inch (11.286 meters). Empty weight of the NA-73X was 6,278 pounds (2,848 kilograms) and normal takeoff weight was 7,965 pounds (3,613 kilograms).

The NA-73X was powered by a liquid-cooled, supercharged, 1,710.60-cubic-inch-displacement (28.032 liter) Allison Engineering Company V-1710-F3R (V-1710-39) single overhead cam 60° V-12 engine, with a compression ratio of 6.65:1 and a single-stage, single-speed supercharger. This was a right-hand tractor engine (the V-1710 was built in both right-hand and left-hand configurations) which drove a 10 foot, 6 inch (3.200 meter) diameter, three-bladed, Curtiss Electric constant-speed propeller through a 2.00:1 gear reduction.

The V-1710-39 had a Normal Power rating of 880 horsepower at 2,600 r.p.m. at Sea Level; Take Off Power rating of 1,150 horsepower at 3,000 r.p.m. at Sea Level, with 44.5 inches of manifold pressure (1.51 Bar), 5 minute limit; and a War Emergency Power rating of 1,490 horsepower at 3,000 r.p.m., with 56 inches of manifold pressure (1.90 Bar). The V-1710-F3R was 3 feet, ¾ inches (0.934 meters) high, 2 feet, 5-9/32 inches (0.744 meters) wide and 7 feet, 1-5/8 inches (2.175 meters) long. It had a dry weight of 1,310 pounds (594 kilograms).

North American Aviation’s prototype fighter, NA-73X, NX19998, at Mines Field, Los Angeles, California. (North American Aviation)

The NA-73X had a maximum speed of 382 miles per hour (615 kilometers per hour) at 13,700 feet (4,176 meters). The service ceiling was 32,000 feet (9,754 meters). The fuel capacity was 180 gallons (681.37 liters), giving the airplane a range of 750 miles (1,207 kilometers).

NX19998 was substantially damaged on 20 November 1940 when North American’s Chief Test Pilot, Paul B. Balfour, unable to make it back to Mines Field after the Allison engine failed, made a forced landing in a plowed field just west of Lincoln Boulevard. The prototype flipped over and landed upside down. Sources differ as to the cause of the engine failure, with some citing carburetor icing and others suggesting that Balfour failed to switch fuel tanks and the engine stopped running due to fuel starvation. Balfour was replaced by Robert C. Chilton and NA-73X was rebuilt.

Robert C. Chilton flying the rebuilt NA-73X on an early familiarization flight. (North American Aviation)

Bob Chilton said that “. . . NA-73X was a clean-flying aircraft with no bad vices. It was quite pleasant in the air and handled very similar to later production articles.”

There was only one NA-73X prototype. Its status is not known. Chilton recalled, “. . . NA-73X was just pushed aside after it had been retired from its last flight. It probably ended up on the company’s junk pile, but I do not recall seeing it there.” The prototype may have been given to a local industrial trade school.

Vance Breese
Vance Breese (San Diego Air and Space Museum Archive)

Vance Breese was born 20 April 1904 at Keystone, Washington, He was the first of five children of Lee Humbert Breese, a machinist, and Anna E. Dixon Breese.

Breese founded the Breese Aircraft Company in 1926, based at San Francisco, California, and then, as the Breese-Wilde Corporation, moved to Oregon. The company produced the Breese-Wilde Model 5, a single-engine light airplane. Two of these, Aloha and Pabco Flyer, flew in the notorious 1927 Dole Air Race from Oakland, California, to Honolulu, Hawaii. Pabco Flyer crashed on takeoff when its landing gear collapsed. Aloha finished in second place.

Breese formed a partnership with Gerard Vultee in 1932, with the Airplane Development Corporation at Detroit Michigan. They produced the Vultee V-1A, an 8 passenger light transport. He was also involved in an express mail company, Air Express Corporation.

Maerican Airlines Vultee !A NC13768, designed by Gerard Vultee and Vance Breese.
American Airlines Vultee 1A NC13768, designed by Gerard Vultee and Vance Breese.

Vance Breese was well known as a test pilot, making a number of first flights and conducting flight tests for various airplane manufacturers. As a test pilot, Breese pioneered the use of recording equipment during flight testing. He used a Dictaphone to record his notes, and a cine camera to film the instruments during the flight.

Breese was married three times. He first married Miss Kathryn (“Kitty”) M. McConnell in 1922. They divorced. Later, Breese married Eleanor Louise Buckles at Los Angeles, California, 18 November 1946. They had a son, Vance Breese, Jr., who became a well-known motorcycle racer and land speed record holder. They divorced in 1967. Breese then married Mireille E. Demartelley (AKA Mireille E. Hunt), 13 July 1967, at Santa Barbara, California.

He died at Santa Monica, California, 26 June 1973, at the age of 69 years. He is an Honorary Fellow of the Society of Experimental Test Pilots.

© 2018, Bryan R. Swopes

24 October 1953

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Convair YF-102 52-7994 on Rogers Dry Lake, Edwards Air Force Base, California. (San Diego Air and Space Museum Archive)
Convair YF-102 52-7994 on Rogers Dry Lake, Edwards Air Force Base, California. (San Diego Air and Space Museum Archive)

24 October 1953: At Edwards Air Force Base, California, Richard Lowe Johnson, Chief Test Pilot for the Convair Division of the General Dynamics Corporation, took the first prototype YF-102 Delta Dagger, serial number 52-7994, for its first flight.

The YF-102 was a single-seat, single-engine, delta wing fighter designed as an all-weather, missile-armed, Mach 2 interceptor. It was developed from the earlier, experimental, Convair XF-92 Dart. The F-102 was planned for a Westinghouse XJ67-W-1 engine, but when that was not ready in time, a Pratt & Whitney J57-P-11 afterburning turbojet engine was substituted. The J57 was a two-spool, axial-flow engine with a 16-stage compressor section (9 low- and 7-high-pressure stages) and a 3-stage turbine section (1 high- and 2 low-pressure stages). The J57-P-11 was rated at 10,000 pounds of thrust (44.482 kilonewtons), and 16,000 pounds (71.172 kilonewtons) with afterburner.

The first prototype Convair YF-102 Delta Dagger, 52-7994, was completed at the Convair plant in San Diego, 2 October 1953. (U.S. Air Force)
The first prototype Convair YF-102 Delta Dagger, 52-7994, was completed at the Convair plant in San Diego, 2 October 1953. (Convair Division of General Dynamics)

The prototype had finished assembly at the Convair plant in San Diego, California, on 2 October 1953. It was then shipped by truck to Edwards Air Force Base in the high desert of southern California where final preparations and testing was carried out.

The National Advisory Committee for Aeronautics (NACA) had tested scale models of the YF-102 in the 8-foot HST wind tunnel at the Langley Memorial Aeronautical laboratory and found that significant shock waves were produced at near-sonic speeds. Surprisingly, shock waves were created at the trailing edge of the delta wing. The shock waves caused very high drag that would keep the aircraft from reaching Mach 1, even with the more powerful engine planned for production models.

Convair YF-102 with the original fuselage. (NASA)
Convair YF-102 53-1785 with the original fuselage, photographed 31 December 1954. (NASA)

The Republic YF-105 fighter bomber had similar problems, though it did pass the speed of sound. Both aircraft were significantly redesigned to incorporate the “Area Rule,” developed by NACA aerodynamicist Richard T. Whitcomb. Rather than considering the aerodynamics of the fuselage independently, the frontal area of the wings and tail surfaces had to be included to reduce drag. This produced the “wasp waist” or “Coke bottle” shape that the production models of these two fighters were known for.

Convair built two YF-102s before the design was changed, resulting in the YF-102A prototypes and the production F-102A Delta Dagger.

The first prototype Convair YF-102 Delta Dagger, 52-7994, on Rogers Dry Lake, October 1953. (U.S. Air Force)
The first prototype Convair YF-102 Delta Dagger, 52-7994, on Rogers Dry Lake, October 1953. (U.S. Air Force)

Several problems showed up on the YF-102’s first flight. Severe buffeting was encountered at high sub-sonic speed. As predicted by NACA, aerodynamic drag prevented the YF-102 from reaching Mach 1 in level flight. There were also problems with the landing gear, the fuel system, and the J57 engine did not produce the rated power.

The production F-102A was considerably larger than the YF-102. The fuselage was lengthened, the wing area and span were increased, and the vertical fin was taller. A more powerful J57-P-23 engine was used. These and other changes increased the F-102A’s gross weight by nearly 1,800 pounds (815 kilograms).

Convair YF-102 52-7994 parked on the dry lake bed, Edwards AFB, California. (U.S. Air Force)

On 2 November 1953, just nine days after the first flight, the Pratt & Whitney J57-P-11 engine flamed out during a test flight. Dick Johnson was unable to restart it and made a forced landing in the desert. The  YF-102 was severely damaged and Dick Johnson badly hurt. The flameout was traced to a problem with the the fuel control system. The prototype was written off.

Convair YF-102 Delta Dagger 52-7994. (U.S. Air Force)
Convair YF-102 Delta Dagger 52-7994 just before touchdown on Rogers Dry Lake. (U.S. Air Force)
Wreck o fConvair YF-102 52-994 near Edwards Air focre Base, 2 Novemnber 1953. (U.S. Air Force)
Wreck of Convair YF-102 52-7994 near Edwards Air Force Base, 2 November 1953. (U.S. Air Force)

Richard Lowe Johnson ¹ was born at Cooperstown, North Dakota, 21 September 1917. He was the eighth of nine children of Swedish immigrants, John N. Johnson, a farmer, and Elna Kristina Helgesten Johnson, a seamstress.

Dick Johnson attended Oregon State College at Corvallis, Oregon, as a member of the Class of 1943. He was a member of the Sigma Alpha Epsilon (ΣΑΕ) fraternity.

Dick Johnson was a pitcher for the college baseball team, and later, played for the Boston Red Sox “farm” (minor league) system.

On 18 June 1942, Johnson enlisted as a private in the Air Corps, United States Army. On 5 November, he was appointed an aviation cadet and assigned to flight training.

Aviation Cadet Johnson married Miss Juanita Blanche Carter, 17 April 1943, at Ocala, Florida. The civil ceremony was officiated by Judge D. R. Smith.

After completing flight training, on 1 October 1943, Richard L. Johnson was commissioned as a second lieutenant, Army of the United States (A.U.S.).

Lieutenant Johnson was assigned to the 66th Fighter Squadron, 57th Fighter Group, Twelfth Air Force, in North Africa, Corsica, and Italy, flying the Republic P-47 Thunderbolt. He was promoted to first lieutenant, A.U.S., 9 August 1944, and just over three months later, 26 November 1944, to the rank of captain, A.U.S. On 14 May 1945, Captain Johnson was promoted to the rank of major, A.U.S. (Major Johnson was assigned a permanent rank of first lieutenant, Air Corps, United States Army, on 5 July 1946, with a date of rank retroactive to 21 September 1945.)

Republic P-47D-25-RE Thunderbolt 42-26421, assigned to the 66th Fighter Squadron, 57th Fighter group, Twelfth Air Force. This airplane was purchased by the employees of Republic Aviation. (American Air Museum in Britain UPL 25505)

During World War II, Major Johnson flew 180 combat missions with the 66th Fighter Squadron. He is officially credited with one air-to-air victory, 1 July 1944. Johnson was awarded the Silver Star, the Distinguished Flying Cross with two oak leaf clusters (3 awards), and the Air Medal with twelve oak leaf clusters (thirteen awards).

In 1946, was assigned to the Air Materiel Command Engineering Test Pilot School at the Army Air Forces Technical Base, Dayton, Ohio (Wright-Patterson Air Force Base). He was the second U.S. Air Force pilot to be publicly acknowledged for breaking the “sound barrier.”

A few weeks after arriving at Dayton, Major Johnson met Miss Alvina Conway Huester, the daughter of an officer in the U.S. Navy. Dick Johnson and his wife Juanita were divorced 8 January 1947, and he married Miss Huester in a ceremony in Henry County, Indiana, 10 January 1947. They would have three children, Kristie, Lisa and Richard.

Richard L. Johnson waves from the cockpit of the record-setting North American Aviation F-86A-1-NA Sabre, 47-611.

Dick Johnson set a Fédération Aéronautique Internationale (FAI) World Record Speed Over a 3 Kilometer Course,² flying the sixth production North American Aviation F-86A-1-NA Sabre, serial number 47-611, at Muroc Air Force Base, California (renamed Edwards AFB in 1949).

During the Korean War, Major Johnson was sent to the war zone to supervise field installations of improvements to the F-86 Sabre. He was “caught” flying “unauthorized” combat missions and was sent home.

Convair Chief Test Pilot Richard Lowe Johnson. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

Lieutenant Colonel Johnson resigned from the Air Force in 1953 to become the Chief Test Pilot for the Convair Division of General Dynamics. He made the first flights of the YF-102 and the F-106A Delta Dart, 26 December 1956. He also made the first flight of the F-111 on 21 December 1964.

In 1955, Johnson was one of the six founding members of the Society of Experimental test Pilots.

Dick Johnson was Chief Engineering Test Pilot for the General Dynamics F-111 “Aardvark.” In 1967, the Society of Experimental Test Pilots awarded Johnson its Iven C. Kincheloe Award for his work on the F-111 program. In 1977, Dick Johnson, then the Director of Flight and Quality Assurance at General Dynamics, retired.

In 1998, Dick Johnson was inducted into the Aerospace Walk of Honor at Lancaster, California. His commemorative monument is located in front of the Lancaster Public Library on W. Lancaster Boulevard, just West of Cedar Avenue. ³

Lieutenant Colonel Richard Lowe Johnson, United States Air Force, (Retired), died 9 November 2002 at Fort Worth, Texas. He was buried at Arlington National Cemetery, Arlington, Virginia, on 7 January 2003.

Chief Test Pilot Dick Johnson in the cockpit of a Convair B-58A Hustler. (Courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

¹ Several sources spell Johnson’s middle name as “Loe.”

² FAI Record File Number 9866

³ Various Internet sources repeat the statement that “Richard Johnson has been honored with. . . the Thompson Trophy, Mackay Trophy, Flying Tiger Trophy, Federation Aeronautique Internationale Gold Medal and Golden Plate Award of the American Academy of Achievement. . . .” TDiA has checked the lists of awardees of each of the appropriate organizations and has not found any support for the statement.

© 2018, Bryan R. Swopes

23 October 1934

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Warrant Officer Francesco Agello, Regia Aeronautica. (FAI)
Warrant Officer Francesco Agello, Regia Aeronautica. (FAI)

23 October 1934: At Lago di Garda, Brescia, Italy, Warrant Officer Francesco Agello, Regia Aeronautica, set a Fédération Aéronautique Internationale (FAI) World Record for Speed Over a 3 Kilometer Course when he flew the Macchi Aeronautica M.C. 72 float plane, serial number MM 181, to an average speed of 709.21 kilometers per hour (440.68 miles per hour).¹

A contemporary news article described the event:

FLYING the Machi-Castoldi 72 seaplane (3,000 h.p. special 24-cyl. Fiat) at Lake Garda on Tuesday of last week, Warrant-Officer Francesco Agello, of the Italian Royal Air Force, raised his own world’s air speed record by putting up a mean speed (subject to homologation) of 709.202 km./hr. (440.677 m.p.h.) for the usual four flights. His previous record stood at 682.403 km./hr. (423.76 m.p.h.)

The weather conditions under which the attempts were made were ideal, there being just sufficient breeze to take the glassiness off the water, so assisting the takeoff. Temperature was suitable, and the air was free from bumps.

Just before 3 p.m. Agello took off and made four runs over the three-kilometre course, clocking as follows:—

[Direction]         Secs.               km./hr.          m.p.h

North-South     15 29/100        705.882        438.614
South-North     15 19.2/100     710.433        441.423
North-South     15 18.1/100     711.462        442.081
South-North     15 23.4/100     709.034        440.738

Warrant Officer Francesco Agello with his Macchi M.C.72. (FAI)
Warrant Officer Francesco Agello with his record-setting Macchi M.C.72, MM 181. (FAI)

After the successful attempt a banquet was held in the Officers’ Mess at Desenzano in Agello’s honour. The speeds were announced, and Col. Bernasconi, who is in command of the High-speed Flight, stated that Signor Mussolini had honoured Warrant-Officer Agello by promoting him to a full lieutenant.

Only a few modifications had been made to the Macchi-Castoldi since the previous attempt, chief among them being the substitution of wooden floats for the metal ones previously used.

Illustration of the Fiat AS.6 V-24 aircraft engine, right side.
Illustration of the Fiat AS.6 DOHC V-24 aircraft engine, right side. (Old Machine Press)

As is well known. the most interesting feature of the machine is the extremely unconventional power-unit, the Fiat A.S.6. The problem of frontal area for such a powerful unit as was specified was solved by placing the twenty-four cylinders (totalling in capacity over fifty litres) in two rows, forming a 60 deg. “vee,” and further, arranging them in two mechanically independent groups.

Each group has its own crank shaft, but a single crank case is used for both. The crank shafts, which rotate in opposite directions, are coupled in the centre by spur-gear reduction units, which drive two airscrew shafts. One of these shafts is hollow, and the other operates within it. The two shafts run forward through the “vee” of the front unit, and each carries an airscrew; so that there are two of the latter, close together, but revolving in opposite directions.

Each engine unit has independent camshafts (two per engine), water pump and dual Marelli magnetos, but a common induction system is used, an eight-jet carburetter being mounted behind the rear unit and mixture being drawn from it passed to the cylinders by a supercharger geared up to 20,000 r.p.m. An interesting point is that this supercharger absorbs 200 h.p., and, since it is driven by the rear engine, the blades of the front airscrew (which the rear engine drives) are given different inclination to correct for the slight difference in power.

The power units develop 3,000 h.p. at 3,200 r.p.m., and weighs 2,045lb., giving a weight per h.p. of 0.706lb. The all-up weight of the machine, with pilot and full tanks, is 6,670lb.

British equipment figured in the success, for Castrol oil and K.L.G. plugs were used.

— FLIGHT, The Aircraft Engineer and Airships, No. 1349, Vol. XXVI, November 1, 1934, at Page 1152.

Warrant Officer Francesco Agello, Regia Aeronautica, with the record-setting Macchi M.C.72, 23 October 1934.
Warrant Officer Francesco Agello, Regia Aeronautica, with the record-setting Macchi M.C.72, 23 October 1934. (Historic Wings)
Left rear quarter view of the Macchi M.C.72. (FAI)
Left rear quarter view of a Macchi M.C.72. (FAI)

The Macchi-Castoldi M.C.72 was designed by Mario Castoldi for Aeronautica Macchi. It was a single-place, single-engine, low-wing monoplane float plane constructed of wood and metal. It was 8.32 meters (27 feet, 3.5 inches) long with a wingspan of 9.48 meters (31 feet, 1.25 inches) and height of 3.30 meters (10.83 feet). The M.C.72 had an empty weight of 2,505 kilograms (5,512 pounds), loaded weight of 2,907 kilograms (6,409 pounds) and maximum takeoff weight of 3,031 kilograms (6,669 pounds).

It was powered by a 50.256 liter (3,067 cubic inch) liquid-cooled, supercharged Fiat S.p.A. AS.6 24-cylinder 60° dual overhead cam (DOHC) V-24 engine with 4 valves per cylinder. The engine produced 3,100 horsepower at 3,300 r.p.m. and drove two counter-rotating metal two-bladed fixed pitch propellers with a diameter of 8 feet (2.56 meters). The counter-rotating blades cancelled the torque effect of the engine.

Surface radiators were placed on top of each wing and surface oil coolers on the floats.

Radiators were placed on the upper surface of each wing. (Aeronautica Militare)
Radiators were placed on the upper surface of each wing. (Aeronautica Militare) 
The Henry De la Vaulx Medal.
The Henry de la Vaulx Medal.

Five Macchi M.C.72 float planes had been built for the 1931 Schneider Trophy race, but problems with the Fiat AS.6 engine, which was essentially two AS.5 V-12s assembled back-to-back, prevented them from competing.

Four test pilots, including Francesco Agello, had been selected to fly the airplanes for speed record attempts. Two were killed while testing the M.C.72, and the third died when another airplane crashed. The cause of the accidents were explosions within the engines’ intake tract. Though they ran perfectly on test stands, in flight, they began to backfire, then explode.

It was discovered by Rod Banks, a British engineer who had been called in to develop a special high-octane fuel, that the Fiat engineers had overlooked the ram effect of the 400 mile per hour slipstream. This caused the fuel mixture to become too lean, resulting in predetonation and backfiring. A modification was made to the intake and the problem was resolved.

Macchi M.C.72 at Aeronautica Militare
Macchi M.C.72 MM 181 at the Museo Storico dell’Aeronautica Militare (Italian Air Force Museum) in Vigna di Valle, Italy. (Unattributed)

Francesco Agello was twice awarded the Henry De La Vaulx Medal by the Fédération Aéronautique Internationale, and also awarded the Medaglia d’oro al valore aeronautico. In part, his citation read, “A high speed pilot of exceptional courage and, after competition in difficult and dangerous test flights during the development of the fastest seaplane in the world, twice he conquered the absolute world speed record.”

Captain Agello was killed in a mid-air collision, 26 November 1942, while testing a Macchi C.202 Fogore fighter.

Medalglia d'oro al valore aeronautico
Medalglia d’oro al valore aeronautico

¹ FAI Record File Number 4497

© 2016, Bryan R. Swopes

22 October 1955

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Republic YF-105A-1-RE 54-098. (U.S. Air Force)
Republic Aviation test pilot Russell M. “Rusty” Roth. (Jet Pilot Overseas)

22 October 1955: At Edwards Air Force Base, in the high desert of southern California, Republic Aviation Corporation test pilot Russell M. (“Rusty”) Roth took the first of two prototype YF-105A-1-REs, serial number 54-098, for its first flight.

Though equipped with an under-powered Pratt & Whitney J57-P-25 interim engine, the new airplane was able to reach Mach 1.2 in level flight.

Aerodynamic improvements to the engine intakes and redesign of the fuselage to incorporate the drag-reducing “area rule,” along with the more powerful J75-P-5 turbojet engine allowed the production model F-105B to reach Mach 2.15.

The first of two Republic YF-105A-1-RE Thunderchief prototypes, 54-098, on Rogers Dry Lake, Edwards Air Force Base, California, 1955. (U.S. Air Force)

The Thunderchief is the largest single-place, single-engine aircraft ever built. It was a Mach 2 fighter-bomber, designed for NATO defensive tactical nuclear strikes with a nuclear bomb carried in an internal bomb bay. The YF-105A was 61 feet, 0 inches (18.593 meters) long, with a wing span of 34 feet, 11 inches (10.643 meters) and overall height of 17 feet, 6 inches (5.334 meters). Its empty weight was 20,454 pounds (9,277 kilograms) and the Maximum Takeoff Weight (MTOW) was 41,500 pounds (18,824 kilograms).

The Pratt & Whitney Turbo Wasp JT3C (J57-P-25) was a two-spool axial-flow turbojet engine with a 16-stage compressor section (9 low- and 7 high-pressure stages) and a 3-stage turbine (1 high- and 2 low-pressure stages). The J57-P-25 had a Normal Power rating of 8,700 pounds of thrust (38.700 kilonewtons), and at Military Power produced 10,200 pounds of thrust (45.372 kilonewtons) (30-minute limit). The Maximum Power rating was 16,000 pounds of thrust (71.172 kilonewtons) with afterburner (5-minute limit). The J57-P-25 was 22 feet, 3.1 inches (6.784 meters) long, 3 feet, 3.8 inches (1.011 meters) in diameter, and weighed 5,120 pounds (2,322 kilograms).

The YF-105A’s wings were swept 45° at 25% chord. The angle of incidence was 0° and there was no twist. The wings had 3° 30′ anhedral. The total wing area was 385 square feet (35.8 square meters).

During testing, the prototype’s maximum speed was 770 knots (886 miles per hour (1,426 kilometers per hour) at 35,000 feet (10,668 meters)—Mach 1.34—and 676 knots (778 miles per hour/1,252 kilometers per hour) at Sea Level—Mach 1.02. The YF-105A’s service ceiling was 52,050 feet (15,865 meters). It’s combat radius was 950 nautical miles (1,093 statute miles/1,759 kilometers), and the maximum ferry range was 2,321 nautical miles (2,671 statute miles/4,298 kilometers).

Repiblic YF-105A 54-098 landing at Edwards Air Force Base. (San Diego Air and Space Museum Archives)
Republic YF-105A 54-098 landing at Edwards Air Force Base. (Ray Wagner Collection, San Diego Air and Space Museum Archives)

The Thunderchief was armed with a General Electric T171E2 (M61) 20 mm six-barrel rotary cannon with 1,030 rounds of ammunition. 8,000 pounds (3,629 kilograms) of bombs could be carried in an internal bomb bay or on external hardpoints. A single free-fall B28IN variable-yield thermonuclear bomb could be carried in the bomb bay.

On 16 December 1955, YF-105A 54-098 made an emergency landing at Edwards AFB after one of its main landing gear assemblies was torn off when it failed to retract during a high speed flight. The pilot, Rusty Roth, was severely injured, but he survived. The prototype was shipped back to Republic for repair, but the cost was determined to be prohibitive.

Though designed for air-to-ground attack missions, F-105s are officially credited with 27.5 victories in air combat.

833 Thunderchiefs were built by Republic between 1955 and 1964. 334 of those were lost to enemy action during the Vietnam War. The F-105 remained in service with the United States Air Force until 1980, and with a few Air National Guard units until 1983.

Republic F-105D-5-RE Thunderchief 58-1173 carrying a bomb load of sixteen 750-pound M117 general purpose bombs. (U.S. Air Force)
Republic F-105D-5-RE Thunderchief 58-1173 carrying a bomb load of sixteen 750-pound M117 general purpose bombs. (U.S. Air Force)

© 2018, Bryan R. Swopes

21 October 1959

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Gerald Huelsbeck
Gerald Huelsbeck

21 October 1959: McDonnell Aircraft Corporation test pilot Gerald (“Zeke”) Huelsbeck was killed while test flying the first prototype YF4H-1 Phantom II, Bureau of Aeronautics serial number (“Bu. No.”) 142259.

The McDonnell YF4H-1 Phantom II, Bu. No. 142259, takes off at Edwards Air Force Base during preparations for Operation Top Flight. (McDonnell Aircraft Corporation)
McDonnell YF4H-1 Phantom II Bu. No. 142259 takes off at Edwards Air Force Base during preparations for Operation Top Flight. (McDonnell Aircraft Corporation)

In October 1959 the Navy tried, a bit prematurely, for its first world record with the F4H. McDonnell test pilot Gerald “Zeke” Huelsbeck, flying near Edwards AFB, was testing various flight plans for a high-altitude zoom, looking for one to recommend to the Navy test pilot who would fly the record attempt. Huelsbeck was flying the very first F4H prototype when an engine access door blew loose, flames shot through the engine compartment, and the F4H crashed, killing Huelsbeck. (Over the next three years of the F4H-1 test program three aircraft were destroyed and three crew members died, all preparing for record flights.)

—Engineering the F-4 Phantom II: Parts Into Systems by Glenn E. Bugos, Naval Institute Press, Annapolis, Maryland, 1996, Chapter 5 at Page 101.

Gerald Huelsbeck
Test Pilot Gerald Huelsbeck with a prototype McDonnell YF4H-1 Phantom II. Huelsbeck is wearing a Goodyear Mk. IV full-pressure suit. (McDonnell Aircraft Corporation)

The flight control system of the YF4H-1 was damaged by the fire and went it out of control at high speed and into a spin. Zeke Huelsbeck did eject but was too low. His parachute did not open. The prototype crashed in an open area near Mt. Pinos in the Los Padres National Forest,  Ventura County, California, about 70 miles (113 kilometers) southwest of Edwards.

McDonnell YF4H-1 Bu. No. 142259 was the first prototype Phantom II. It had first been flown by Robert C. Little at Lambert Field, St. Louis, Missouri, 27 May 1958. The Phantom II was designed as a supersonic, high-altitude fleet defense interceptor for the United States Navy. It was a two-place twin engine jet fighter armed with radar- and infrared-homing air-to-air missiles.

Gerald Huelsbeck was born in Wisconsin, 16 April 1928, the third child of Walter Andrew Huelsbeck, a farmer, and Irene M. Voigt Huelsbeck. He attended Carroll College (now, Carroll University) in Waukesha, before joining the United States Navy as a midshipman. He completed flight training at NAS Whiting Field, Florida, and was commissioned as an ensign, 2 June 1950.

In 1950, Ensign Gerald Huelsbeck married Miss Mary Jean Hillary, who had also attended Carroll College. They would have two children.

Huelsbeck was promoted to lieutenant (junior grade), 2 June 1952. Assigned as a fighter pilot during the Korean War, he flew 54 combat missions in the McDonnell F2H Banshee.

While flying in the Navy, Huelsbeck experimented with helmet-mounted cine cameras:

. . . He took a standard gun camera, added a couple of gadgets, and attached it to his helmet, The camera is electrically driven and able to take about two minutes of film with a 50-foot magazine. . . “I spent some time doing ‘hand camera’ work in Korea,” he recalls. “You know, after 54 combat missions, you don’t like to think about crashing while trying to take a picture.”

—The Indianapolis Star, Vol. 53, No. 116, Tuesday, 29 September 1955, Page 4 at Columns 2–4

Lt. (j.g.) Huelsbeck in teh cocpit of a Grumman F9F. A small motion picture camera is attached to his flight helmet (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)
Lt. (j.g.) Huelsbeck in the cockpit of a U.S. Navy fighter. A small motion picture camera is attached to his flight helmet. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

He was serving with VF-11 at NAS Jacksonville, Florida, when he was selected for the United States Naval Test Pilot School at NAS Patuxent River, Maryland, in July 1953.

“Zeke” Huelsbeck left the Navy in 1955 to accept a position as a test pilot with the McDonnell Aircraft Corporation, St. Louis, Missouri. After several months, he was assigned as an experimental test pilot and project pilot of the F4H program.

At the time of the accident, Zeke Huelsbeck was the most experienced pilot flying the F4H.

Gerald Huelsbeck was 31 years old when he died. He is buried in New Berlin, Wisconsin.

McDonnell YF4H-1 Phantom II, Bu. No. 142259, at Lambert Field, St. Louis. (McDonnell Aircraft Corporations)
McDonnell YF4H-1 Phantom II, Bu. No. 142259, at Lambert Field, St. Louis. (McDonnell Aircraft Corporations)

© 2016, Bryan R. Swopes