Tag Archives: First Flight

25 October 1994: The “Dog Ship”

The prototype Bell Model 430, C-GBLL, in flight, circa 1994. (Bell Helicopter TEXTRON)

A “dog ship” is an aircraft retained by a manufacturer for engineering development testing.

25 October 1994: At Bell Helicopter Textron’s plant at Mirabel, Quebec, Canada, the prototype Bell Model 430, registered C-GBLL, made its first flight.

The Bell Model 430 (“Four-Thirty”) is a twin-engine intermediate-weight helicopter, operated by one or two pilots, and which can be configured to carry from 6 to 11 passengers. It has advanced avionics. The standard helicopter is equipped with skid landing gear, and retractable tricycle gear is optional. The 430 was the first helicopter to be certified for instrument flight with a single pilot, without a stability augmentation system. The aircraft is also certified for Category A operations, meaning that if one engine were to fail during takeoff, the helicopter could continue to fly with the remaining engine.

Bell 430 instrument panel with some optional equipment. (Bell Helicopter TEXTRON)

The 430 was developed from the preceding Model 230 (and the 230 from the 222). It was lengthened 1 foot, 6 inches (0.457 meters) and uses a four-bladed semi-rigid main rotor.  Instead of a mechanical rotor head of trunnions, bearings and hinges, the 430 has a “soft-in-plane” fiberglass rotor yoke that is flexible enough to allow the blades to flap, feather and lead/lag.

The Bell 430 is 50 feet, 0.6 inches (15.248 meters) long, with rotors turning. The fuselage is 44 feet, 1 inch (13.437 meters) long. Overall height 12 feet, 1.6 inches (3.697 meters). The span of the stub wings is 11 feet, 6.0 inches (3.454 meters). The fixed horizontal stabilizer has a spa of 11 feet, 5.9 inches (3.453 meters) and a -9° angle of incidence. The vertical fin is canted slightly to the right to unload the tail rotor during high speed flight.

The main rotor mast is tilted 5° forward and 1.15° to the left. The forward tilt helps to keep the passenger cabin level during forward flight, while the left tilt counteracts the translating tendency caused by tail rotor thrust while in a hover.

Bell 430 prototype at Mirabel, Quebec, Canada, December 1995. (Vertiflite)

The main rotor is 42 feet, 0 inches (12.802 meters) in diameter and rotates counter-clockwise as seen from above. (The advancing blade is on the right.) The rotor turns at 348 r.p.m., resulting in a blade tip speed of 765 feet per second (233 meters per second). The blades are of composite construction. They use an asymmetrical airfoil and have a chord of 1 foot, 2.2 inches (0.361 meters). The blades are pre-coned 2° 30′.

The tail rotor is mounted on the left side of the tail boom, with the rotor disc offset 1 foot, 9.5 inches (0.572 meters) to the left of the aircraft centerline. Seen from the helicopter’s left, the tail rotor turns clockwise (the advancing blade is below the axis of rotation). The tail rotor is 6 feet, 10.5 inches (2.098 meters) in diameter, with a chord of 10.0 inches (0.254 meters). The blades are constructed of a stainless steel spar, with a bonded stainless steel skin over an aluminum honeycomb. The tail rotor turns 1,881 r.p.m.

Three-view drawing of the Bell Model 430 with retractable tricycle landing gear. (Bell Helicopter TEXTRON)

In standard configuration, the wheel-equipped Model 430 has an empty weight of 5,364 pounds. Its maximum gross weight is 9,300 pounds (4,218 kilograms).

The 430 is powered by two Rolls-Royce Series IV M250 C40B FADEC turboshaft engines. (The engine was previously known as the Allison 250-C40B. Rolls-Royce acquired Allison in 1995). The engine has full digital electronic controls. The 250-C40B uses a single-stage centrifugal compressor, reverse-flow combustion chamber, and a 4-stage axial-flow turbine section (2-stage gas producer turbine, N1, and 2-stage power turbine, N2.) At 100% N1, the gas producer rotates at 51,000 r.p.m. and the power turbine turns 30,908 r.p.m. The output drive speed is 9,598 r.p.m.

The engines have a Maximum Continuous Power rating of 695 shaft horsepower, and 808 s.h.p. for takeoff (5-minute limit). If an engine fails, the remaining engine can be operated at 940 s.h.p. for 30 seconds; 880 s.h.p for 2 minutes; and 835 s.h.p. for 30 minutes.

At Sea Level, the Bell Model 430 has a cruise speed of 133 knots (153 miles per hour/246 kilometers per hour), and maximum cruise of 147 knots (169 miles per hour/272 kilometers per hour). VNE is 150 knots (173 miles per hour/278 kilometers per hour). The helicopter’s service ceiling is 20,000 feet (6,096 meters). At its maximum gross weight, the 430 can hover in ground effect (HIGE) at 10,400 feet (3,170 meters) and out of ground effect (HOGE) at 6,200 feet (1,890 meters).

The fuel capacity of the 430 is 187.5 U.S. gallons (708 liters). This gives the helicopter a range of 286 nautical miles (329 statute miles/530 kilometers). A 48 gallon (182 liter) auxiliary fuel tank can be installed in the baggage compartment. With skid landing gear, the fuel capacity is increased to 247 gallons (935 liters), increasing the range to 353 nautical miles (406 statute miles/654 kilometers).

The Bell Model 430 received its Transport Canada certification on 23 February 1996, with the first production aircraft delivered the following month. Production continued for 12 years. The final 430 was delivered in May 2008.

This helicopter is an early production Bell Model 222, sometimes unofficially called a “222A”. (Wikipedia)

C-GBLL was originally built as the sixth Model 222, serial number 47006, and registered by the Federal Aviation Administration as N2759D. The aircraft was used as the prototype of the Bell 222B, which upgraded the engines from the original 618-shaft horsepower Lycoming LTS-101-650C3 turboshaft engines to 680 s.h.p. LTS-101-750Cs. The diameter of the main rotor was increased from 40 feet to 42 feet.

In 1983, N2759D was next used as the prototype for the Model 222UT, which replaced the retractable tricycle landing gear with fixed skids constructed of tubular aluminum. This simplified the helicopter, decreased its empty weight and allowed for an increased fuel capacity. N2759D was transferred to Bell Helicopter Textron Canada at Mirabel. Its U.S. registration cancelled by the FAA on 17 October 1990, and it was re-registered C-GBLL by Transport Canada.

The skid-equipped Bell Model 222UT is often used as an emergency medical transport helicopter. This aircraft, operated by Mercy Air Service Inc., is standing by at Mohave Airport (MHV) in the high desert of southern California. (Unattributed)

Early problems with the Lycoming LTS-101 adversely affected sales of the Bell 222. Bell designed a new variant equipped with Allison 250-C30G engines. This helicopter was designated the Model 230. The first prototype, C-GEXP, with skid gear, made its first flight on 12 August 1991, followed by the second prototype—C-GBLL—on 3 October 1991.

Bell 230 prototype C-GBLL, minus main rotor and mast, and tail rotor, circa 1993. Compare the exhaust stacks to those of the 222UT in the image above. (Fiveprime)

The 430 prototype was given a new serial number, s/n 43901.

Bell 430 prototype C-GBLL, stripped, circa 2012. (Photograph © Pierre Gillard. Used with permission)
Bell 430 C-BCHD (s/n 43902) was the second prototype of the Model 430. This helicopter, previously registered C-GEXP, was built as a Bell 222UT, s/n 47503, before being converted to the first Model 230 prototype in 1991. (© Pierre Gillard Used with permission)

© 2018, Bryan R. Swopes

24 October 1953

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

24 October 1947

Grumman Model G-64, XJR2F-1 Pelican. (Уголок неба)

24 October 1947: First flight, prototype Grumman Model G-64, the XJR2F-1 Pelican. This amphibian would become the Grumman UF-1 Albatross. (In U.S. Air Force service, the Albatross was designated SA-16A. In 1962, this was changed to HU-16A for Navy, Coast Guard and USAF.)

Interestingly, several months earlier, the National Advisory Committee for Aeronautics (NACA) conducted landing tests using a 1:7-scale model XJ2RF-1 in a test tank at the Langley Memorial Aeronautical Laboratory. Wave heights of 4.4 and 8.0 inches (11.2 and 20.3 centimeters) were used, with wave lengths between 10 feet and 50 feet (3–15 meters). Tests indicated that the amphibian could be expected to experience a maximum of 8.5 gs.

Grumman G-64, XJ2RF-1 Pelican (U.S. Coast Guard)

The Albatross was operated by a crew of 4 to 6 airmen, and could carry up to 10 passengers. The SA-16A amphibian was 62 feet, 10 inches (19.152 meters) long, with a wingspan (before modification) of 80 feet, 0 inches (24.384 meters) and had an overall height of 25 feet, 11 inches (7.899 meters). The wing had an angle of incidence of 5° and the total wing area was 883 square feet (82.03 square meters).

The SA-16A was modified to the SA-16B standard, increasing the wingspan to 96 feet, 8 inches (29.464 meters) and the wing area to 1,035 square feet (96.15 square meters). The wing’s leading edges were altered and larger tail surfaces were added.

The HU-16B had an empty weight of 23,025 pounds (10,444 kilograms), and maximum takeoff weight of 37,500 pounds (17,010 kilograms). For takeoff from water, the airplane’s weight was limited to 34,000 pound (15,422 kilograms), using rocket assist. The maximum weight for landing on water was 32,000 pounds (14,515 kilograms).

The SA-16 was powered by two air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.876 liter) Wright Aeronautical Division Cyclone 9 826C9HD3 and -D5 (R-1820-76A and -76B) nine-cylinder radial engines with a compression ratio of 6.80:1. 115/145 octane aviation gasoline was required. These engines were rated at 1,275 horsepower at 2,500 r.p.m., and 1,425 horsepower at 2,700 r.p.m for takeoff. The engines drove three-bladed Hamilton Standard Hydromatic full-feathering, reversible-pitch propellers with a diameter of 11 feet, 0 inches (3.353 meters) through a 0.666:1 gear reduction. The R-1820-76A and -76B were 3 feet, 11.69 inches (1.211 meters) long and 4 feet, 6.95 inches (1.396 meters) in diameter, and weighed 1,380 pounds (626 kilograms).

The Albatross could be equipped with two or four Aerojet 14AS1000 RATO units, which produced 1,000 pounds of thrust (4.49 kilonewtons), each, for 15 seconds.

The flying boat had a cruise speed of 134 knots (154 miles per hour/248 kilometers per hour) and a maximum speed of 204 knots (235 miles per hour/378 kilometers per hour) at 3,700 feet (1,128 meters). The service ceiling was 23,800 feet (7,254 meters). The SA-16B had a combat radius of 725 nautical miles (834 statute miles/1,343 kilometers), and 1,130 nautical miles (1,300 statute miles/2,093 kilometers) with two 300-gallon (1,136 liters) drop tanks.

This former U.S. Coast Guard UF-1G (HU-16E) Albatross is now privately owned. (paxdaus)

© 2018, Bryan R. Swopes

22 October 1955

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 1947

Northrop YB-49 42-102367 takes off from Northrop Field, Hawthorne, California. (U.S. Air Force)

21 October 1947: At Northrop Field, Hawthorne, California, Northrop Corporation Chief Test Pilot Max R. Stanley took off in the first YB-49, 42-102367, and flew it to Muroc Air Force Base for flight testing. The co-pilot was Fred C. Bretcher and Orva H. Douglas served as flight test engineer. The Flying Wing landed at Muroc 34 minutes later.

(Pasadena Star-News, 26 October 1947, Page 40, Columns 2–4)

An estimated 4,000 spectators lined the streets surrounding Northrop Field. The YB-49 was escorted by a Lockheed P-80A Shooting Star and a Northrop P-61 Black Widow as it climbed to 10,000 feet (3,048 meters) en route to Muroc. Over Lancaster, California, the P-61 caught fire and was abandoned by its crew.

42-102367 had been converted from the second YB-35 pre-production test aircraft. The original Flying Wing’s four Pratt & Whitney Wasp Major (R-4360-21) radial engines were replaced by turbojet engines and several aerodynamic improvements were made.

Chief Test Pilot Max R. Stanley. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

The YB-49 was a very unusual configuration for an aircraft of that time. There was no fuselage or tail control surfaces. The crew compartment, engines, fuel, landing gear and armament were contained within the wing. Air intakes for the turbojet engines were placed in the leading edge and the exhaust nozzles were at the trailing edge. Four small vertical fins for improved yaw stability were also at the trailing edge.

Northrop YB-49 42-102367. (U.S. Air Force)
Northrop YB-49 42-102367 at Northrop Field, Hawthorne, California. (Unattributed)

The YB-49 had a length of 53 feet, 1 inch (16.180 meters), wingspan of 172 feet (52.426 meters) and overall height of 15 feet, 2 inches (4.623 meters). It weighed 88,442 pounds (40,117 kilograms) empty and its Maximum Takeoff Weight (MTOW) was 193,938 pounds (87,969 kilograms).

The Wing defined the airplane. The leading edge was swept aft 26° 57′ 48″, and the trailing edge, 10° 15′ 22″. The wing’s total area was 4,000 square feet (371.6 square meters). It had an aspect ratio of 7.4:1. At the root, the chord was 37 feet, 6 inches (11.430 meters), tapering to 9 feet, 4 inches (2.844 meters) at the tip. There was 0° angle of incidence at the root, -4° at the wing tips, and 0° 53′ dihedral.

Northrop YB-49 42-102367 in flight near Muroc Air Force Base. (U.S. Air Force)

The YB-49 was powered by eight General Electric-designed, Allison Engine Company-built J35-A-5 engines. (This same engine variant was used in the North American Aviation XP-86, replacing its original Chevrolet-built J35-C-3.) The engines were later upgraded to J35-A-15s. The J35 was a single-spool, axial-flow turbojet engine with an 11-stage compressor and single-stage turbine. The J35-A-15 had a Normal Power rating of 3,270 pounds of thrust (14.546 kilonewtons) at 7,400 r.p.m. The Military Power rating was 3,750 pounds (16.681 kilonewtons) at 7,700 r.p.m. The engine was 14 feet, 0.0 inches (4.267 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter and weighed 2,400 pounds (1,089 kilograms).

The YB-49 had four vertical fins extending above and below the trailing edge of the Wing. (U.S. Air Force 090706-F-1234K-048)

During testing the YB-49 reached a maximum speed of 428 knots (493 miles per hour/793 kilometers per hour) at 20,800 feet (6,340 meters). Cruise speed was 365 knots (429 miles per hour/690 kilometers per hour). The airplane had a service ceiling of 49,700 feet (15,149 meters). The YB-49 had a maximum fuel capacity of 14,542 gallons (55,047 liters) of JP-1 jet fuel. Its combat radius was 1,403 nautical miles (1,615 statute miles/2,598 kilometers).

The maximum bomb load of the YB-49 was 16,000 pounds (7,257 kilograms), though the actual number of bombs was limited by the volume of the bomb bay and the capacity of each bomb type. While the YB-35 Flying Wing was planned for multiple machine gun turrets, the YB-49 carried no defensive armament.

Northrop YB-49 42-102367 takes off from Northrop Field, Hawthorne California. Note teh crowds of onlookers and residential housing along W. 120th Street, on the north side of the airport. (U.S. Air Force)
Northrop YB-49 42-102367 takes off from Northrop Field, Hawthorne, California. Note the crowds of onlookers and residential housing along W. 120th Street, on the north side of the airport. (Unattributed)

Only two Northrop YB-49s were built and they were tested by Northrop and the Air Force for nearly two years. Though an additional nine YB-35s were ordered converted, the B-49 was not placed into production.

A Northrop YB-49 with a Boeing XB-47 Stratojet. (U.S. Air Force)

The second ship, YB-49 42-102368, disintegrated in flight during a test flight north of Muroc Air Force Base, 5 June 1948, killing the entire crew, which included Captain Glen Edwards. The name of Muroc was changed to Edwards Air Force Base in his honor.

YB-49 42-102367 was destroyed by fire following a taxiing accident at Edwards, 15 March 1950. The program was cancelled on the same day.

© 2024, Bryan R. Swopes