Tag Archives: NACA

7 May 1937

Lockheed XC-35 36-353 in flight. (U.S. Air Force)

7 May 1937: First flight of the Lockheed XC-35, Air Corps serial number 36-353. Ordered by the Air Corps in 1936 as a high-altitude research aircraft, and for the development of cabin pressurization, the XC-35 Supercharged Cabin Transport Airplane was a highly modified Lockheed Electra 10A. It was the first airplane to be specifically built with a pressurized cabin.

The Army Air Corps was awarded the Collier Trophy for 1937 for the XC-35 project.

With a strengthened circular fuselage and smaller windows, the XC-35′s passenger compartment was pressurized by engine turbo-superchargers and controlled by a flight engineer. Cabin pressure could be maintained at the equivalent of 12,000 feet (3,658 meters) above sea level, at an actual altitude of 30,000 feet (9,144 meters).

A crew of three and two passengers were accommodated within the pressurized section, and there was room for another passenger to the rear of the pressure bulkhead, which could only be used at lower altitudes.

The Lockheed XC-35 was powered by two air-cooled, supercharged, 1,343.804-cubic-inch-displacement (22.021 liter) Pratt & Whitney R-1340-43 (Wasp T5H1) single-row, nine-cylinder radial engines with a compression ratio of 6:1. The R-1340-43 had a Normal and Takeoff Power rating of 550 horsepower at 2,200 r.p.m. from Sea Level to 3,000 feet (914 meters), burning 92-octane gasoline. It was direct drive. The engine was 3 feet, 6.25 inches (1.073 meters) long, 4 feet, 3.50 inches (1.308 meters) in diameter, and weighed 864 pounds (392 kilograms).

Able to fly above 30,000 feet (9,144 meters), the XC-35 was later used by NACA for thunderstorm penetration research flights. In 1948 it was transferred to the Smithsonian Institution.

Lockheed XC-35 35-363. (U.S. Air Force)
Lockheed XC-35 36-353. (U.S. Air Force)

© 2017, Bryan R. Swopes

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25 April 1956

Lieutenant Colonel Frank K. Everest, U.S. Air Force, with a Bell X-2 at Edwards Air Force Base. Colonel Everest is wearing a capstan-type partial pressure suit for protection at very high altitude. (U.S. Air Force)
Lieutenant Colonel Frank K. Everest, U.S. Air Force, with a Bell X-2 at Edwards Air Force Base. Colonel Everest is wearing a David Clark Co. T-1 capstan-type partial-pressure suit for protection at very high altitude. (U.S. Air Force)

25 April 1956: At Edwards Air Force Base, California, test pilot Lieutenant Colonel Frank Kendall (“Pete”) Everest, United States Air Force, was airdropped from a Boeing EB-50D Superfortress in the Bell X-2 supersonic research rocket plane, serial number 46-674. This was the tenth flight of the X-2 program, and only the third powered flight.

For the first time, Everest fired both chambers of the Curtiss-Wright XLR25 rocket engine. On this flight, the X-2 reached Mach 1.40 and 50,000 feet (15,240 meters). It was the first time an X-2 had gone supersonic.

Bell X-2 46-674 in flight over Southern California, circa 1955–56. (NASA Photograph ET–128)
Bell X-2 46-674 in flight over Southern California, circa 1955–56. (NASA Photograph ET–128)

The X-2 was a joint project of the U.S. Air Force and NACA (the National Advisory Committee on Aeronautics, the predecessor of NASA). The rocketplane was designed and built by Bell Aircraft Corporation of Buffalo, New York, to explore supersonic flight at speeds beyond the capabilities of the earlier Bell X-1 and Douglas D-558-II Skyrocket.

In addition to the aerodynamic effects of speeds in the Mach 2.0–Mach 3.0 range, engineers knew that the high temperatures created by aerodynamic friction would be a problem, so the aircraft was built from stainless steel and K-Monel, a copper-nickel alloy.

The Bell Aircraft Corporation X-2 was 37 feet, 10 inches (11.532 meters) long with a wingspan of 32 feet, 3 inches (9.830 meters) and height of 11 feet, 10 inches (3.607 meters). Its empty weight was 12,375 pounds (5,613 kilograms) and loaded weight was 24,910 pounds (11,299 kilograms).

The X-2 was powered by a throttleable two-chamber Curtiss-Wright XLR25-CW-1 rocket engine that produced 2,500–15,000 pounds of thrust (11.12–66.72 kilonewtons)

Rather than use its limited fuel capacity to take off and climb to altitude, the X-2 was dropped from a modified heavy bomber as had been the earlier rocketplanes. A four-engine Boeing B-50D-95-BO Superfortress bomber, serial number 48-096, was modified as the drop ship and redesignated EB-50D.

Bell X-2 46-674 on final approach. (NASA)

The launch altitude was 30,000 feet (9,144 meters). After the fuel was exhausted, the X-2 glided to a touchdown on Rogers Dry Lake at Edwards Air Force Base.

Two X-2 rocketplanes were built. The second X-2, 46-675, was destroyed during a captive flight, 12 May 1953. The explosion killed Bell test pilot Skip Ziegler and Frank Wolko, an engineer aboard the B-50A mothership. The B-50 made an emergency landing but was so badly damaged that it never flew again.

The X-2 reached a maximum speed of Mach 3.196 (2,094 miles per hour/3,370 kilometers per hour) and maximum altitude of 126,200 feet (38,466 meters).

Boeing EB-50D Superfortress 49-096 with a Bell X-2 (U.S. Air Force)
Boeing EB-50D Superfortress 48-096 with a Bell X-2 (U.S. Air Force)

The EB-50D was a highly modified four-engine Boeing B-50D-95-BO Superfortress long range heavy bomber, engineered to carry research aircraft to high altitudes before releasing them for a test flight. The B-50 was an improved version of the World War II B-29A Superfortress.

Boeing B-50D-95-BO (S/N 48-096) in flight. (U.S. Air Force photo)
Boeing B-50D-95-BO Superfortress 48-096 prior to modification to an EB-50D X-2 carrier. (U.S. Air Force/Bill Pippin Collection, 1000aircraftphotos.com)
Boeing B-50D-90-BO Superfortress 48-096 prior to modification to an EB-50D X-2 carrier. (U.S. Air Force)
Boeing B-50D-95-BO Superfortress 48-096 prior to modification to an EB-50D X-2 carrier. (U.S. Air Force)
Boeing B-50D-95-BO Superfortress 48-096 prior to modification to an EB-50D X-2 carrier. (U.S. Air Force)

Frank Kendall (“Pete”) Everest, Jr., was born 10 Aug 1920, at Fairmont, Marion County, West Virginia. He was the first of two children of Frank Kendall Everest, an electrical contractor, and Phyllis Gail Walker Everest. Attended Fairmont Senior High School, Fairmont, West Virginia, graduating in 1939. He studied at Fairmont State Teachers College, also in Fairmont, West Virginia, and then studied engineering at teh University of Wesst Virginia in Morgantown.

Pete Everest enlisted as an aviation cadet in the United States Army Air Corps at Fort Hayes, Columbus, Ohio, 7 November 1941, shortly before the United States entered World War II. His enlistment records indicate that he was 5 feet, 7 inches (1.703 meters) tall and weighed 132 pounds (59.9 kilograms). He graduated from pilot training and was commissioned as a second lieutenant, Air Reserve, 3 July 1942.

Everest married Miss Avis June Mason in Marion, West Virginia, in 1942.

He was promoted to 1st Lieutenant, Army of the United States, 11 November 1942. He was assigned as a Curtiss-Wright P-40 Warhawk pilot, flying 94 combat missions in North Africa, Sicily and Italy. He was credited with shooting down two German airplanes and damaging a third. Everest was promoted to the rank of Captain, 17 August 1943.

In 1944, Everest was returned to the United States to serve as a flight instructor. He requested a return to combat and was then sent to the China-Burma-India theater of operations where he flew 67 missions and shot down four Japanese airplanes. He was himself shot down by ground fire in May 1945. Everest was captured by the Japanese and suffered torture and inhumane conditions before being freed at the end of the war. He was promoted to the rank of major, 1 July 1945. He was returned to the United States military 3 October 1945.

After the war, Everest was assigned as a test pilot at Wright-Patterson Air Force Base, Ohio, before going west to the Air Force Flight Test Center at Edwards Air Force Base, California.

Everest was returned to the permanent rank of first lieutenant, Air Corps, 19 June 1947, with date of rank retroactive to 3 July 1945.

Major Frank Kendall Everest, Jr., U.S. Air Force, with a Bell X-1 supersonic research rocketplane, 46-062, circa 1950. (mach-buster.co.uk)

At Edwards, he was involved in nearly every flight test program, flying the F-88, F-92, F-100, F-101, F-102, F-104 and F-105 fighters, the XB-51, YB-52, B-57 and B-66 bombers. He also flew the pure research aircraft, the “X planes:” the X-1, X-1B, X-2, X-3, X-4 and X-5. Pete Everest flew the X-1B to Mach 2.3, and he set a world speed record with the X-2 at Mach 2.9 (1,957 miles per hour, 3,149.5 kilometers per hour) which earned him the title, “The Fastest Man Alive.” He was the test pilot on thirteen of the twenty X-2 flights.

Major Frank Kendall Everest, Jr., U.S. Air Force, with the Bell X-2 supersonic research rocketplane, on Rogers Dry Lake at Edwards AFB, California, 1956. (U.S. Air Force via Jet Pilot Overseas)

Frank Everest returned to operational assignments and commanded a fighter squadron, two combat crew training wings, and was assigned staff positions at the Pentagon. On 20 November 1963, Colonel Everest, commanding the 4453rd Combat Crew Training Squadron, flew one of the first two operational McDonnell F-4C Phantom II fighters from the factory in St. Louis to MacDill Air Force Base.

In 1965, Pete Everest was promoted to the rank of brigadier general. He was commander of the Aerospace Rescue and Recovery Service. He retired from the Air Force in 1973 after 33 years of service. He later worked as a test pilot for Sikorsky Aircraft.

During his military career General Everest was awarded the Air Force Distinguished Service Medal; Legion of Merit with two oak leaf clusters (three awards); Distinguished Flying Cross with two oak leaf clusters (three awards); Purple Heart; Air Medal with one silver and two bronze oak leaf clusters (seven awards); Air Force Commendation Medal with one oak leaf cluster (two awards); Presidential Unit Citation with two bronze oak leaf clusters (three awards); Air Force Gallant Unit Citation; Prisoner of War Medal; American Campaign Medal; European-African-Middle Eastern Campaign medal with four bronze stars; Asiatic-Pacific campaign Medal with two bronze stars; World War II Victory Medal; National Defense Service Medal; Armed Forces Expeditionary Medal; Vietnam Service Medal; Air Force Longevity Service Award with one silver and two bronze oak leaf clusters (seven awards); Air Force Small Arms Expert Marksmanship Ribbon; and the Republic of Vietnam Campaign Medal with 1960– device. General Everest was rated as a Command Pilot, and a Basic Parachutist.

Brigadier General Frank Kendall Everest, Jr. United States Air Force (Retired), died at Tucson, Arizona, 1 October 2004 at the age of 84 years.

Brigadier General Frank Kendall Everest, United states Air Force
Brigadier General Frank Kendall Everest, Jr., United States Air Force. (U.s. Air Force)

© 2018, Bryan R. Swopes

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24 April 1939

The Curtiss XP-40 prototype at Langley Field in the original configuration. (NASA)
The Curtiss-Wright XP-40 prototype, 36-10, at Langley Field in the original configuration. Compare this to the first production P-40 Warhawk in the photograph below. (NASA)
Curtiss P-40 Warhawk 39-156. (U.S. Air Force)
Curtiss-Wright P-40 Warhawk 39-156. (U.S. Air Force)

24 April 1939: Curtiss-Wright’s prototype fighter, the XP-40 (Model 75P), was evaluated by the National Advisory Committee for Aeronautics (NACA) at the Langley Memorial Aeronautical Laboratory, Langley Field, Virginia, in March and April 1939. NACA engineers placed the XP-40 inside the Full-Scale Wind Tunnel, which was capable of accepting airplanes with wing spans of up to 40 feet (12.2 meters).

Compare this production Curtiss-Wright P-36A Hawk to the first production P-40 Warhawk in the photograph below.
Curtiss Model 81, P-40 Warhawk, 39-156. (San Diego Air and Space Museum Archive)

The airplane was a production Curtiss P-36A Hawk, serial number 38-10, which had been modified by replacing its original air-cooled Pratt & Whitney Twin Wasp S1C1-G (R-1830-17) 14-cylinder radial engine with a Harold Caminez-designed, liquid-cooled, supercharged, 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Co. V-1710-C13 (V-1710-19). This was a single overhead cam (SOHC) 60° V-12 engine with four valves per cylinder and a compression ration of 6.65:1. It had a Normal Power rating of 910 horsepower at 2,600 r.p.m. at Sea Level, and 1,060 horsepower at 2,950 r.p.m. for Takeoff. At 10,000 feet (3,048 meters), the V-1710-19 had Maximum Continuous Power rating of 1,000 horsepower at 2,600 r.p.m., and Military Power rating of 1,150 horsepower at 2,950 r.p.m. The engine required 100/130-octane aviation gasoline. It drove a three-bladed Curtiss Electric constant-speed propeller through a 2:1 gear reduction. The V-1710-19 was 8 feet, 1.75 inches (2.483 meters) long, 3 feet, 4.75″ (1.035 meters) high and 2 feet, 4.94 inches (0.735 meters) wide. It weighed 1,320 pounds (599 kilograms).

Curtiss XP-40 prototype in the NACA wind tunnel at Langley Field, Virginia, 24 April 1939. The technician at the lower left of the photograph provides scale. (NASA)
Curtiss-Wright XP-40 prototype in the NACA wind tunnel at Langley Field, Virginia, 24 April 1939. The technician at the lower left of the photograph provides scale. (NASA)

The primary benefit of the engine change was the streamlined fuselage that resulted. The new airplane was capable of a speed of 366 miles per hour (589 kilometers per hour), a 53 miles per hour (85 kilometers per hour) increase over the P-36.

Over a two-month period, NACA engineers made a number of improvements. The radiator was moved forward under the engine and the oil coolers utilized the same air scoop. The exhaust manifolds were improved as were the landing gear doors.

When they had finished, Lieutenant Benjamin Scovill Kelsey flew the modified XP-40 back to Curtiss at Buffalo, New York. Its speed had been increased to 354 miles per hour (570 kilometers per hour), a 12% improvement. Other improvements were recommended which may have increased the XP-40’s speed by an additional 18 miles per hour (29 kilometers per hour). By December 1939, the airplane had been further improved and was capable of 366 miles per hour (589 kilometers per hour).

These photographs show the full-size prototype in the NACA wind tunnel at Langley, 24 April 1939. Two days later, the U.S. Army Air Corps ordered 524 airplanes as the P-40 Warhawk. By the time production ended in 1945, 13,738 Warhawks had been built.

Curtiss XP-40 in the NACA full scale wind tunnel, Langley Field, Virginia, April 1939. (NASA)
Curtiss XP-40 in the NACA full scale wind tunnel, Langley Field, Virginia, April 1939. (NASA)

© 2018, Bryan R. Swopes

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14 April 1947

Douglas test pilot Gene May with a D-558-I Skystreak high-speed research airplane. (Douglas Aircraft Company)
Douglas Aircraft Company test pilot Eugene Francis May. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

14 April 1947: Douglas Aircraft Company test pilot Eugene Francis (“Gene”) May took the Number 1  U.S. Navy/NACA/Douglas D-558-I Skystreak high-speed research aircraft, Bu. No. 37970, for its first flight at at Muroc Army Airfield. The aircraft had been transported from the Los Angeles factory to Muroc by truck.

The Skystreak was a joint United States Navy/National Advisory Committee for Aeronautics (NACA) research aircraft designed to explore flight at high subsonic speed. The Phase I Skystreak was designed by a team led by Douglas Chief Engineer Edward Henry Heinemann. Flight testing was conducted at the NACA High Speed Flight Station at Muroc Army Airfield (later known as Edwards Air Force Base). Three D-558-Is were built, followed by the Phase II, swept-wing, Mach 2, D-558-II Skyrocket rocketplane.

The D-558-I carried extensive flight test instrumentation for its time. The wings had 400 orifices for air pressure sensors. During the test series, aircraft stability in the range of 0.82–0.99 Mach was investigated. One of the Skystreaks may have briefly exceeded Mach 1 as it came out of a dive.

Unlike some of the other experimental high speed aircraft of the time, it took off from the ground under its own power rather than being carried aloft by a mother ship. While those other aircraft could briefly reach much higher speeds, the D-558-I was able to fly for extended periods in the high-subsonic range, providing scientists and engineers with a tremendous amount of data.

The research airplane was a single-place, single-engine, low-wing monoplane with retractable tricycle landing gear. The fuselage of the D-558-I was constructed of an aluminum framework covered with sheet magnesium. It was designed for an ultimate load factor of 18 gs. The wings and tail surfaces were aluminum. The airplane was painted scarlet (not orange, like its contemporary, the Bell X-1) and was known as “the crimson test tube.” The D-558-I was 35 feet, 1.5 inches (10.706 meters) long with a wingspan of 25 feet, 0 inches (7.620 meters) and overall height of 12 feet, 1.6 inches (3.698 meters). Gross weight 10,105 pounds (4,584 kilograms). It carried 230 gallons (871 liters) of kerosene in its wings.

A Douglas D-558-I Skystreak being inspected by U.S. Navy personnel at the Douglas Aircraft Company plant in Los Angeles, California. [Modelers: Note the GREEN anti-glare panel.] (Getty Images/Bettman)
The D-558-I was powered by a single Allison J35-A-11 turbojet engine. The J35 was a single-spool, axial-flow turbojet with an 11-stage compressor section, 8 combustion chambers and single-stage turbine. The J35-A-11 was rated at 5,000 pounds of thrust (22.24 kilonewtons). The engine was 12 feet, 1.0 inches (3.683 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter and weighed 2,455 pounds (1,114 kilograms).

Bu. No. 37970 made 101 of the 228 Phase I flights. It set a world speed record 1,031.178 kilometers per hour (640.744 miles per hour), flown by Commander Turner F. Caldwell Jr., U.S. Navy,  20 August 1947.¹ (Major Marion E. Carl, U.S. Marine Corps, flew the second Skystreak, Bu. No. 37971, to 1,047.356 kilometers per hour (650.797 miles per hour),² breaking Caldwell’s record.)

After Douglas completed the contractor’s test series, the Number 1 Skystreak was turned over to the NACA High Speed Flight Station and designated NACA 140. It was not as highly instrumented as the Number 2 and Number 3 Skystreaks and was not flown, but was used as a source for spare parts for the other D-558-Is.

Douglas D-558-I Skystreak Bu. No. 37970 is on display at the National Naval Aviation Museum, NAS Pensacola, Florida.

Douglas D-558-I Skystreak, Bu. No. 37970, at the National Naval Aviation Museum, Naval Air Station Pensacola, Florida. (U.S. Navy)

¹ FAI Record File Number 9864

² FAI Record File Number 9865

© 2017, Bryan R. Swopes

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20 November 1953

NACA test pilot Scott Crossfield in the cockpit of the Douglas D-558-II Skyrocket after his record-setting flight, 20 November 1953. (NASA) 20 November 1953: At Edwards Air Force Base, California, NACA’s High Speed Flight Station test pilot Albert Scott Crossfield rode behind the flight crew of the Boeing P2B-1S Superfortress as it carried the Douglas Aircraft Company D-558-II Skyrocket supersonic research rocketplane to its launch altitude. As the four-engine bomber climbed through 18,000 feet (5,486 meters), Crossfield headed back to the bomb bay to enter the Skyrocket’s cockpit and prepare for his flight.

The Douglas D-558-II was Phase II of a U.S. Navy/Douglas Aircraft Company/National Advisory Committee on Aeronautics joint research project exploring supersonic flight. It was a swept-wing airplane powered by a single Reaction Motors LR8-RM-6 four-chamber rocket engine. The Skyrocket was fueled with alcohol and liquid oxygen. The engine was rated at 6,000 pounds of thrust (26.69 kilonewtons) at Sea Level.

There were three Phase II aircraft. Originally, they were also equipped with a Westinghouse J34-W-40 turbojet engine which produced 3,000 pounds of thrust (13.35 kilonewtons) and the Skyrockets took off from the surface of Rogers Dry Lake. Once the D-558-II reached altitude, the rocket engine was fired for the speed runs. As higher speeds were required, the program shifted to an air launch from a B-29 (P2B-1S) “mothership”. Without the need to climb to the test altitude, the Skyrocket’s fuel load was available for the high speed runs.

NACA 144. a Douglas D-558-II Skyrocket, Bu. No. 37974, on Rogers Dry Lake. (NASA)
NACA 144. a Douglas D-558-II Skyrocket, Bu. No. 37974, on Rogers Dry Lake. (NASA)

The D-558-II was 42.0 feet (12.80 meters) long, with a wingspan of 25.0 feet (7.62 meters). The leading edge of the wing was swept at a 35° angle and the tail surfaces were swept to 40°. The aircraft weighed 9,421 pounds (4,273 kilograms) empty and had a maximum takeoff weight of 15,787 pounds (7,161 kilograms). It carried 378 gallons (1,431 liters) of water/ethyl alcohol and 345 gallons (1,306 liters) of liquid oxygen.

The mothership, NACA 137, was a Boeing Wichita B-29-95-BW Superfortress, U.S. Air Force serial number 45-21787. It was transferred to the U.S. Navy, redesignated P2B-1S and assigned Bureau of Aeronautics number 84029. Douglas Aircraft modified the bomber for its drop ship role at the El Segundo plant.

Douglas D-558-II Skyrocket, Bu. No., 37974, NACA 144, is dropped from the Boeing P2B-1S Superfortress, Bu. No. 84029, NACA 137. (NASA)
Douglas D-558-II Skyrocket, Bu. No. 37974, NACA 144, is dropped from the Boeing P2B-1S Superfortress, Bu. No. 84029, NACA 137. (NASA)

Going above the planned launch altitude, the Superfortress was placed in a slight dive to build to its maximum speed. At the bomber’s critical Mach number (Mcr), the Skyrocket was just above its stall speed. At 32,000 feet (9,754 meters), Crossfield and the Skyrocket were released. The rocketplane fell for about 400 feet (122 meters) until the rocket engine ignited and then it began to accelerate.

Crossfield climbed at a steep angle until he reached 72,000 feet (21,946 meters), and then leveled off. Now in level flight, the D-558-II accelerated, quickly passing Mach 1, then Mach 1.5. Crossfield pushed the nose down and began a shallow dive. The Skyrocket, still under full power, built up speed. As it passed through 62,000 feet (18,998 meters) the Skyrocket reached its maximum speed, Mach 2.005, or 1,291 miles per hour (2,078 kilometers per hour).

Scott Crossfield and the Douglas D-558-II Skyrocket, with their support team: two North American F-86 Sabre chase planes and the Boeing P2B-1S Superfortress mothership, at the NACA High Speed Flight Station, Edwards Air Force Base, California, 1 January 1954. (NASA)
Scott Crossfield and the Douglas D-558-II Skyrocket, with their support team: two North American F-86 Sabre chase planes and the Boeing P2B-1S Superfortress mothership, at the NACA High Speed Flight Station, Edwards Air Force Base, California, 1 January 1954. (NASA)

Scott Crossfield was the first pilot to fly an aircraft beyond Mach 2, twice the speed of sound. During his career as a test pilot, he flew the Douglas D-558-II, the Bell X-1, Bell X-2 and North American X-15. He made 112 flights in rocket-powered aircraft, more than any other pilot.

NACA Test Pilot Albert Scott Crossfield on Rogers Dry Lake. (NASA)
NACA Test Pilot Albert Scott Crossfield on Rogers Dry Lake. (NASA)

© 2016, Bryan R. Swopes

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