Curtiss-Wright

Curtiss Hawk 75-O, developed for Argentine Army Aviation, as an export Hawk 75 variant.

After leaving the military in 1933, Fisher joined Curtiss-Wright, and was assigned to test pilot duties. In checking out aircraft off the production lines at the Buffalo, New York, plant, on his first day, he flew 10 aircraft.^{[N 2]} During his 15 years with Curtiss-Wright as Chief Production Test Pilot, Fisher recorded thousands of test flight hours in the Curtiss C-46 Commando, Curtiss P-36/Model 75 Hawk, Curtiss SB2C Helldivers, Curtiss P-40 Warhawks and Republic P-47 Thunderbolt fighters.^{[N 3]} He flew 2,498 P-40s in his role as a production test pilot.^{[4][N 4]}

Curtiss company executives, with Fisher (at center), indicating the highly decorated P-40N,^{[N 5]} the firm's 15,000th fighter, November 1944.

In 1942, due to wartime priorities that prohibited the use of military aircraft for Hollywood productions, Republic Studios approached Curtiss-Wright in Buffalo to recreate the aerial battle sequences required for Flying Tigers, starring John Wayne.^[11] A number of P-40E fighter aircraft waiting for USAAC delivery were repainted in AVG markings, and with the aid of Curtiss test pilots, flew in the film. Fisher's screen role was in subbing for John Wayne.^[12]

At the request of the commander of the Flying Tigers, Claire Chennault, Chief Engineer Don R. Berlin sent Fisher abroad as the best way to have "imparted his experience on those courageous young fellows over there with knowledge they could not possibility have".^[7] During 13 months overseas from 1943 on, despite his being a civilian test pilot, while in the China-Burma-India (CBI) theater, Fisher flew as many as 50 missions to prove the P-40 under combat conditions. He also lectured and conducted P-40 flight demonstrations in almost every fighter base in the CBI, Middle East, North and Central Africa.^[5]

Curtiss C-46 Commando

Fisher with Curtiss-Wright Fire Chief John L. Ward, note Caldwell in background, August 6, 1942.

Fisher was also instrumental in supporting the introduction of the Curtiss C-46 at the Engineering and Operation section of the Air Transport Command. On August 6, 1942, first-hand experience with a faulty landing gear on an early production C-46, led to an example of his coolness in critical situations.^[13] While on an acceptance re-flight, the aircraft was loaded with Curtiss executives, and a special guest, fresh from combat in North Africa, Australian P-40 ace, Group Captain Clive "Killer" Caldwell. With the landing gear stuck in a three-quarters down position, and after an extended eight-hour attempt to release the gear, Fisher calmly belly-landed the C-46. With the weight of the aircraft gently pushing the gear back into the wheel wells, a minimum of damage resulted. Caldwell had taken over as the co-pilot on the eight hours of circling over Buffalo, receiving certification that he was checked out on the C-46, under the tutelage of Fisher.^[14] Recognizing that the new transport was subject to teething problems common to any new type, Fisher was able to assist operational units in the technique of flying and maintaining C-46 transports. He would eventually fly 96 "research missions" over "The Hump" as a means of testing all the critical systems and troubleshooting a dangerous tendency for the engine fires and explosions that had plagued the C-46.^[15] CBI C-46 pilot Don Downie recalled, "Herb Fisher's detailed reports were some of the best pilot briefings we had."^[16]

Through his hard work and persistence, Fisher also convinced American General Joseph Stilwell, the Vice Commander of the CBI theater, that the new operational procedures would save the lives of hundreds of pilots and passengers. In 1944, at a special ceremony in Washington, D.C., President Franklin D. Roosevelt awarded the Air Medal to Fisher in recognition of his service; he was the first living civilian to receive the honor.^[4]

Compressibility effects

After test flights of a P-47C on November 13, 1942, Republic Aviation issued a press release on December 1, 1942, claiming that Lts. Harold E. Comstock and fellow test pilot Roger Dyar had exceeded the speed of sound.^[17] In response, Fisher later observed, "We knew about Mach 1 going clear back to the P-36 and the P-40 ... Nothing could go 600 mph (970 km/h) mph in level flight, but pilots were beginning to dive fighters. We ran into compressibility back in '38."^[18]

The desire to develop a propeller that maintained its efficiency at transonic and supersonic speeds led the Curtiss-Wright Propeller Division to design and test several different concepts, including a thin, cuffed four-blade and a three-bladed "scimitar" design. Utilizing a specially modified P-47D-30-RE on loan from the USAAF,^{[N 6]} Fisher undertook over 100 high Mach number precision dives from 38,000 ft (11,582 m) at speeds from 500 mph (800 km/h) to 590 mph (950 km/h).^{[N 7]} The typical flight began above 35,000 ft (10,668 m) when Fisher would push over into a steep dive, allowing his airspeed to build beyond 560 mph (900 km/h) (true airspeed).^[21] He would then execute a pullout at 18,000 ft (5,486 m), having to maintain an exacting set altitude within plus or minus five ft.^[9]

Some of the tests proved hazardous with flexing of the thin blades on the ground run-ups. Test flights also had to be carefully flown as engine power could only be fed in gradually for the same reason. The most serious incident, though one unconnected with compressibility, occurred in August 1948 when a rupture of a high pressure oil line at 590 mph (950 km/h) mph over Allentown, Pennsylvania, led to an emergency "blind" landing with the entire aircraft coated in black oil.^[22] Several of these dives resulted in speeds of Mach 0.83; one on 27 October 1949 reached the fastest speed a P-47 could attain.^[23]

During the test program, Fisher brought his son, Herbert O. Fisher, Jr., along for a Mach 0.80 dive. The youngster was touted as "the world's fastest toddler".^[3]

Douglas C-54 Skymaster

Reversible pitch experiments

Fisher also conducted a program designed to allow aircraft to descend rapidly. It involved reversing all four propellers simultaneously in flight. On a Douglas C-54 Skymaster transport, the extremely high sink rates of up to 15,000 feet per minute in four seconds after reversal, produced a safe method of rapid descent for airliners. The flight would start at 15,000 ft., three miles from the airfield before push over, landing and coming to a full stop in one minute and 50 seconds. Fisher wrote that forward airspeed was well within normal parameters (200 mph (320 km/h)), with no decrease in controllability.^[3]

Fisher conducted nearly 200 of these high rate/low speed descents and demonstrated the technique for Generals"Hap" Arnold and Dwight Eisenhower in 1948. For the latest pressurized airliners and combat aircraft that operated at high altitudes, this was an effective method of safely dumping altitude in the event of an emergency, and was adopted worldwide as a safe procedure.^[24] Fisher was also instrumental in developing the use of reversing pitch to rapidly slow an aircraft, which allowed them to land safely on shorter runways, and, in general, greatly reduce the incidence of runway overruns.^[5]

Grumman F8F Bearcat

Later, flying a U.S. Navy Grumman F8F Bearcat fighter, Fisher developed a way to fly "zero-g", vertical dives. From 20,000 ft, the F8F would be nosed down into a vertical dive, while he simultaneously reversed the propeller pitch. This technique allowed a controlled vertical dive at rates of descent that varied between 30,000 and 37,000 fpm.^[3]

Fisher with the P-40 in which he had his 2,500th flight in the type, c. 1976.

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