Tag Archives: Prototype

29 April 1988

Aviation, , , , , , , , , , , , , , ,
N401PW, the first Boeing 747-400 airliner. (The Boeing Company)

29 April 1988: Boeing test pilots James C. Loesch and Kenneth Higgins take the new Boeing 747-400, serial number 23719, registration N401PW, for its first flight from Paine Field, landing at Boeing Field 2 hours 29 minutes later.

The 747-400 was a major development of the 747 series. It had many structural and electronics improvements over the earlier models, which had debuted 18 years earlier. New systems, such as a “glass cockpit”, flight management computers, and new engines allowed it to be flown with a crew of just two pilots, and the position of Flight Engineer became unnecessary.

Roll-out, Boeing 747-400 c/n 23719. (The Boeing Company)

The most visible features of the –400 are its longer upper deck and the six-foot tall “winglets” at the end of each wing, which improve aerodynamic efficiency be limiting the formation of wing-tip vortices.

On 27 June 1988, this 747-400 set a Maximum Takeoff Weight record for airliners by lifting off at Moses Lake, Washington at 892,450 pounds (405,659 kilograms).¹ At the time of its first flight, Boeing had already received orders for 100 747-400s. It would become the most popular version, with 694 aircraft built by the time production came to an end 15 March 2007.

Cockpit of a Boeing 747-400 airliner.
Cockpit of a Boeing 747-400 airliner. 

The Boeing 747-400 airliner can carry between 416 and 660 passengers, depending on configuration. It is 231 feet, 10 inches (70.6 meters) long with a wingspan of 211 feet, 5 inches (64.4 meters) and overall height of 63 feet, 8 inches (19.4 meters). Empty weight is 394,100 pounds (178,800 kilograms). Maximum takeoff weight (MTOW) is 875,000 pounds (396,890 kilograms).

Northwest Boeing 747-451 N661US
Northwest Boeing 747-451 N661US on approach to Osaka. (Wikipedia Commons)

While the prototype was powered by four Pratt & Whitney PW4056 turbofan engines, production airplanes could be ordered with PW4062, General Electric CF6 or Rolls-Royce RB211 engines, providing thrust ranging from 59,500 to 63,300 pounds.

The –400 has a cruise speed of 0.85 Mach (567 miles per hour, 912 kilometers per hour) and maximum speed of 0.92 Mach (614 miles per hour, 988 kilometers hour). Maximum range at maximum payload weight is 7,260 nautical miles (13,450 kilometers).

Northwest Airlines' Boeing 747-451 N661US on approach to Osaka Kansai International Airport, 11 June 2007. (Photograph courtesy of Dennis Lau)
Northwest Airlines’ Boeing 747-451, N661US, on approach to Osaka Kansai International Airport, 11 June 2007. (Photograph courtesy of Dennis Lau)

After the test program was completed, the prototype 747-400 was outfitted for airline service. It was operated by Northwestern Airlines and is currently in service with Delta Air Lines. It has been re-registered as N661US, and carries the Delta fleet number 6301.

N661US was the aircraft operated as Northwest Airlines Flight 85 on 9 October 2002 when it suffered a rudder hardover while over the North Pacific Ocean. The aircraft went into a sudden 40° left bank when a hydraulic power unit for the lower rudder failed due to a fatigue fracture. This incident is considered to be an excellent example of Cockpit Resource Management (CRM) as the flight crew successfully landed the airplane at Anchorage, Alaska.

Boeing 747-451 N661US, Delta Air Lines, landing at Tokyo-Narita International Airport, 25 July 2009. (Photograph courtesy of Kazuchika Naya)
Boeing 747-451 N661US, Delta Air Lines, landing at Tokyo-Narita International Airport, 25 July 2009. (Photograph courtesy of Kazuchika Naya)

After flying its final revenue flight, 9 September 2015, as Flight 836, Honolulu to Atlanta, N661US was stored at Delta Technical Operations. It is now displayed at the Delta Flight Museum, Hartsfield Jackson International Airport.

Delta’s Ship 6301, N661US, completes its final flight, landing at Hartsfield Jackson International Airport, Atlanta, Georgia, 9 September 2015. (Delta Flight Museum)

¹ FAI Record File Number 2203)

© 2019, Bryan R. Swopes

26 April 1948

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est Pilot George Welch flying the prototype North American Aviation XP-86 Sabre, 45-59597. (U.S. Air Force)
North American Aviation test pilot George S. Welch, flying the first of three XP-86 prototypes, serial number 45-59597. (North American Aviation, Inc.)

26 April 1948: At Muroc Field (now known as Edwards Air Force Base), in the high desert of southern California, North American Aviation test pilot George Welch put the prototype XP-86 Sabre, 45-59597, into a 40° dive and broke the Sound Barrier. It is only the second U.S. aircraft to fly supersonic. The first was the Bell X-1, piloted by Chuck Yeager, only a few months earlier.

Or, maybe not.

In his book, Aces Wild: The Race For Mach 1, fellow North American Aviation test pilot Albert W. Blackburn makes the case that George Welch had taken the prototype XP-86 Sabre supersonic on its first flight, 1 October 1947, and that he had done so three times before Chuck Yeager first broke the Sound Barrier with the Bell X-1 rocketplane, 14 October 1947. Blackburn described two runs through the NACA radar theodolite with speeds of Mach 1.02 and 1.04 on 13 November 1947.

Mr. Blackburn speculates—convincingly, in my opinion—that Secretary of the Air Force W. Stuart Symington, Jr., ordered that Welch’s excursions beyond Mach 1 were to remain secret. However, during a radio interview, British test pilot Wing Commander Roland Prosper (“Bee”) Beamont, C.B.E, D.S.O. and Bar, D.F.C. and Bar, stated that he had flown through the Sound Barrier in the number two XP-86 Sabre prototype (45-59598). Once that news became public, the U.S. Air Force released a statement that George Welch had flown beyond Mach 1 earlier, but gave the date as 26 April 1948.

Test pilot George S. Welch, wearing his distinctive orange helmet, in the cockpit of the prototype XP-86. This photograph was taken 14 October 1947. (U.S. Air Force)
Test pilot George S. Welch, wearing his distinctive orange helmet, in the cockpit of the prototype XP-86. This photograph was taken 14 October 1947. (U.S. Air Force)

It wasn’t long after the first flight of the XP-86 on October 1, 1947, that Welch dropped into Horkey’s [Edward J. Horkey, an aerodynamicist at North American Aviation] office at the Inglewood plant. He wanted to talk about his recent flight and some “funny” readings in the airspeed indicator. He had made a straight-out climb to more than 35,000 feet. Then, turning back toward Muroc Dry Lake, he began a full-power, fairly steep descent.

“I started at about 290 knots,” Welch was explaining to Horkey. “In no time I’m at 350. I’m still going down, and I’m still accelerating but the airspeed indicator seems stuck like there’s some kind of obstruction in the pitot tube. I push over a little steeper and by this time I’m through 30,000 feet. All of a sudden, the airspeed indicator flips to 410 knots. The aircraft feels fine, no funny noises, no vibration. Wanted to roll off to the left, but no big deal. Still, I leveled out at about 25,000 and came back on the power. The airspeed flicked back to 390. What do you think?”

“. . . You may be running into some Mach effects. . . .”

— Aces Wild: The Race For Mach 1, by Al Blackburn, Scholarly Resources Inc., Wilmington, Delaware, 1999, at Pages 147–148.

The “funny” reading of the airspeed indicator became known as the “Mach jump.” George Welch was the first to describe it.

The Sabre became a legendary jet fighter during the Korean War. 9,860 were built by North American, as well as by licensees in Canada, Australia and Japan.

George Welch had been recommended for the Medal of Honor for his actions as a P-40 Warhawk fighter pilot in Hawaii, December 7, 1941. He was killed while testing a North American Aviation F-100A Super Sabre, 12 October 1954.

Test pilot George S. Welch with a North American Aviation F-86 Sabre. (San Diego Air and Space Museum Archives)

© 2018, Bryan R. Swopes

19 April 1960

Aviation, , , , , , , ,
Grumman YA2F-1 Inruder Bu. No. 147864 (San Diego Air and Space Museum Archives)
Grumman YA2F-1 Intruder Bu. No. 147864 with landing gear extended during the first flight, 19 April 1960. (San Diego Air and Space Museum Archives)

19 April 1960: Grumman Aircraft Engineering Corporation test pilot Robert K. Smyth made the first flight of the prototype YA2F-1 Intruder, Bu. No. 147864, at the Grumman Peconic River Airport (CTO), Calverton, Long Island, New York. During the flight, Smyth climbed to 15,000 feet (4,572 meters). The landing gear remained extended during the flight. At one point, Smyth attempted to retract it, but a malfunction was indicated, so they remained down and locked. The first flight lasted one hour.

During follow-on flights, Bob Smyth and project test pilot Ernie von der Heyden (who flew the photo-chase plane during the first flight) alternated left and right seats.

Bu. No. 147864 was painted gray with U.S. Navy markings before being accepted by the Navy on 29 April 1960. The airplane was lost 31 May 1960.

Grumman test pilot Robert K. Smyth in the cockpit of the YA2F-1 prototype, Bu. No. 147864, 29 April 1960. With Program manager Bruce Tuttle and VP Larry Mead. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)
Grumman test pilot Robert K. Smyth in the cockpit of the YA2F-1 prototype, Bu. No. 147864, 29 April 1960. With Program manager Bruce Tuttle and VP Larry Mead. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

Eight Grumman YA2F-1 Intruders were built for the test program.  They were redesignated A-6A Intruder in 1962.

The Grumman A-6A Intruder was a carrier-based, all-weather attack bomber powered by two turbojet engines. It was operated by a pilot and a bombardier/navigator, or “b/n,” in a side-by-side cockpit. The wings were slightly swept.

The A2F-1 was 53 feet, 3 inches (16.231 meters) long with a wing span of 53 feet, 0 inches (16.154 meters) and overall height of 15 feet, 2 inches (4.623 meters). The wings had a total area of 528.9 square feet (49.14 square meters) and were swept aft to 25° at 25% chord. The aircraft had an empty weight of 23,412 pounds (10,620 kilograms) and maximum takeoff weight of 53,278 pounds (24,166 kilograms).

Grumman YA2F-1 Intruder, Bu. No. 147864, in Navy markings. (San Diego Air and Space Museum Archives)
Grumman YA2F-1 Intruder, Bu. No. 147864, in Navy markings. (San Diego Air & Space Museum Archives)
Grumman A2F-1 Intruder (A-6A) three-view illustration with dimensions. (U.S. Navy)

The prototypes were powered by two Pratt & Whitney J52-P-6 turbojet engines which had previously been used on the North American Aviation AGM-28 Hound Dog cruise missile. The J52 was a two-spool, axial-flow turbojet with a 12-stage compressor section (5 low- and 7 high-pressure stages) and 2-stage (1 high- and 1-low pressure stages). The engines had a normal power rating of 7,500 pounds of thrust (33.36 kilonewtons) at 11,400 r.p.m., and a maximum of 8,500 pounds (37.81 kilonewtons) at 11,650 r.p.m. The J52-P-6 was 31 inches (0.787 meters) in diameter, 127 inches (3.226 meters) long, and weighed 2,056 pounds (933 kilograms) The engine incorporated an exhaust nozzle that could be swiveled downward 23° to assist in short field takeoffs.

The A-6A had a cruise speed of 429 knots (493 miles per hour/795 kilometers per hour) at 44,450 feet (13,548 meters) and a maximum speed of 566 knots (651 miles per hour/1,048 kilometers per hour) at Sea Level. The service ceiling was 48,250 feet (14,707 meters), and the maximum range was 2,061 nautical miles (2,372 statute miles/3,817 kilometers).

The initial production Intruders could carry 18,000 pounds ( kilograms) of bombs on hardpoints under the wings. It could also carry AIM-9 Sidewinder air to air, or AGM-12 Bullpup air to ground missiles. “Special Weapons” that could be carried included Mk. 28 or Mk. 43 thermonuclear bombs.

The Intruder was a very successful combat aircraft with 693 built in attack, tanker and electronic warfare variants. They remained in service with the United States Navy until 1997.

Grumman YA2F-1 (A-6A) Intruder Bu. No. 147867, the third prototype, carrying thirty Mk. 82 low-drag bombs on multiple ejector racks under the wings and fuselage. (U.S. Navy)
Grumman YA2F-1 (A-6A) Intruder Bu. No. 147867, the third prototype, carrying thirty Mk. 82 low-drag 500-pound bombs on multiple ejector racks under the wings and fuselage. (U.S. Navy)

© 2019 Bryan R. Swopes

18 April 1952

Aviation, , , , , , , , , , , , ,
Convair YB-60-1-CF 49-2676 takes off on a test flight. (U.S. Air Force)

18 April 1952: Piloted by Chief Test Pilot Beryl A. Erickson, and Arthur S. Witchell, the prototype Consolidated-Vultee YB-60-1-CF, serial number 49-2676, made its first takeoff at Carswell Air Force Base, Fort Worth, Texas.

As a proposed competitor to Boeing’s B-52 Stratofortress, the YB-60 (originally designated B-36G) was developed from a B-36F fuselage by adding swept wings and tail surfaces and powered by eight turbojet engines. Its bomb load was expected to be nearly double that of the B-52 and it would have been much cheaper to produce since it was based on an existing operational bomber.

Test pilot Beryl A. Erickson waves from the cockpit of the YB-60. (Convair, via Jet Pilot Overseas.)
Test pilot Beryl A. Erickson waves from the cockpit of the YB-60. (Jet Pilot Overseas.)

The Associated Press reported:

New Jet ‘Rides Like Cadillac’, Crew Says After Test Flight

     FORT WORTH, April 18 (AP)—The all-jet YB-60 bomber “rides like a Cadillac” and “touched at fighter speed,” crew members said Friday after the ultra-secret global bomber completed its first test flight.

   “I came back with very little perspiration, B.A. Erickson, chief test pilot for Consolidated Vultee Aircraft Corp. said. “That’s the answer to any pilot.”

  Erickson tried the YB-60’s performance and capabilities only “modestly,” he said. The flight was made at a moderate altitude—”a couple of Texas miles,” Erickson said.

Rides Like Cadillac

     “The YB-60 rode like a Cadillac with no noise like a B-36—no prop noise or vibration,” Arthur S. Witchell Jr., the co-pilot, said.

“This is the Queen Mary coming in gracefully,” Erickson said.

     The YB-60, an eight-jet bomber sometimes called a jet version of the B-36, was in the air one hour and six minutes. Erickson said it “touched at fighter speed.”

The plane is about the same size as the B-36, Erickson said. “Most any B-36 pilot would feel right at home,” he said.

Higher Speed Tests

     Witchell said tests would probably be made soon at higher speeds and higher altitudes.

The plane took off with a deep roar, with a shrill, whining overtone. Several thousand spectators, including Air Force personnel from Carswell Air Force Base, home of the B-36, lined the left side of the Carswell runway and stood on rooftops.

     The spectators were able to distinguish little more than the YB-60’s extreme, almost-triangular swept-back shape.

     The YB-60 made a rendezvous in the air with a B-25 Air Force camera plane from which highly secret photographs were taken.

—Valley Morning Star, Volume XLII, No. 271, Saturday 19 April 1952, Page 1 at Columns 3 and 4.

Consolidated-Vultee YB-60 (Jet Pilot Overseas)
Consolidated-Vultee YB-60 49-2676. (Jet Pilot Overseas)

The YB-60’s first flight was three days after that of the Boeing YB-52 Stratofortress. In testing, it was 100 miles per hour (161 kilometers) slower than the B-52 prototype, despite using the same engines. A second B-60 prototype was cancelled before completion, and after 66 flight hours the YB-60 test program was cancelled. Both airframes were scrapped in 1954, with the second prototype never having flown.

The Convair YB-60 was 171 feet (52.121 meters) long with a wingspan of 206 feet (62.789 meters) and overall height of 60 feet, 6 inches (18.440 meters). The wings were swept at a 37° angle. It had an empty weight of 153,016 pounds (69,407 kilograms) and gross weight of 300,000 pounds (136,078 kilograms).

Consolidated-Vultee YB-60-1-CF 49-2676. (U.S. Air Force)

The prototype jet bomber was powered by eight Pratt & Whitney Turbo Wasp YJ57-P-3 turbojet engines. The J57 was a two-spool, axial-flow turbojet developed from an experimental turboprop engine. It had 16-stage compressor section (9 low- and 7-high-pressure stages), 8 combustors and a 3-stage turbine section (1 high- and 2 low-pressure stages). The YJ57-P-3s were rated at 8,700 pounds of thrust (38.70 kilonewtons), each. The YJ57-P-3 was 183.5 inches (4.661 meters) long, 41.0 inches (1.041 meters) in diameter and weighed 4,390 pounds (1,991 kilograms). These were the same engines used in the YB-52, and were similarly mounted in four 2-engine nacelles below the wings.

Right profile of the first prototype YB-60. Note the tail landing gear strut. (Jet Pilot Overseas)
Right profile of the first prototype YB-60. Note the tail landing gear strut. (Jet Pilot Overseas)

Maximum speed was 0.77 Mach (508 miles per hour, 818 kilometers per hour) at 39,250 feet (11,963 meters) and the combat ceiling was 44,650 feet (13,609 meters). The YB-60 could reach 30,000 feet (9,144 meters) in just over 28 minutes. Takeoff required 6,710 feet (2,045 meters) and 8,131 feet (2478 meters) were required to clear a 50-foot (15.24 meters) obstacle. Maximum range was 8,000 miles (12,875 kilometers) but the combat radius was 2,920 miles (4,699 kilometers) with a 10,000 pound (4,536 kilograms) bomb load.

The maximum bomb load was 72,000 pounds (32,659 kilograms). Defensive armament consisted of two M24A1 20 mm autocannon in a remote-controlled tail turret. The second YB-60 retained the upper forward and lower aft retractable gun turrets of the B-36, adding eight more 20 mm cannon.

Chief Test Pilot Beryl Arthur Erickson. (Convair)
Chief Test Pilot Beryl Arthur Erickson. (Convair)

© 2017, Bryan R. Swopes

16 April 1949

Aviation, , , , , , , , , , ,
Tony Levier and  Glenn Fulkerson in the prototype Lockheed YF-94. (Lockheed Martin)

16 April 1949: At Van Nuys Airport, California, test pilot Tony LeVier and flight test engineer Glenn Fulkerson made the first flight of the Lockheed YF-94 prototype, serial number 48-356. The aircraft was the first jet-powered all-weather interceptor in service with the United States Air Force and was the first production aircraft powered by an afterburning engine.

Prototype Lockheed YF-94 48-356, first flight, 16 April 1949. (U.S. Air Force)

Two prototypes were built at Lockheed Plant B-9, located on the east side of Van Nuys Airport. Two TF-80C-1-LO (later redesignated T-33A) Shooting Star two-place trainers, 48-356 and 48-373, were modified with the installation of air intercept radar, an electronic fire control system, radar gun sight, four Browning AN-M3 .50-caliber (12.7 × 99 NATO) aircraft machine guns and a more powerful Allison J33-A-33 turbojet engine with water-alcohol injection and afterburner. The rear cockpit was equipped as a radar intercept officer’s station.

The prototype Lockheed YF-94 test fires its four .50-caliber guns at Van Nuys, California. (Lockheed Martin)

It was initially thought that the project would be a very simple, straightforward modification. However, the increased weight of guns and electronics required the installation of a more powerful engine than used in the T-33A. The new engine required that the aft fuselage be lengthened and deepened. Still, early models used approximately 80% of the parts for the F-80C fighter and T-33A trainer. The Air Force ordered the aircraft as the F-94A. Improvements resulted in an F-94B version, but the definitive model was the all-rocket-armed F-94C Starfire.

The prototype Lockheed YF-94, 48-356. (U.S. Air Force)

The Allison J33-A-33 was a single-shaft turbojet engine with a single-stage centrifugal-flow compressor, 14 combustion chambers and, a single-stage axial flow turbine. The engine was rated at 4,600 pounds of thrust (20.46 kilonewtons) and 6,000 pounds (26.69 kilonewtons) with afterburner. The J33-A-33 was 17 feet, 11.0 inches (5.461 meters) long, 4 feet, 1.3 inches (1.252 meters) in diameter and weighed 2,390 pounds (1,084 kilograms).

Originally a P-80C Shooting Star single-place fighter, 48-356 had been modified at Lockheed Plant B-9 in Van Nuys to become the prototype TF-80C two-place jet trainer (the designation was soon changed to T-33A), which first flew 22 March 1948. It was then modified as the prototype YF-94. 48-356 was later modified as the prototype F-94B. It is in the collection of the Air Force Flight Test Museum, Edwards Air Force Base, and is in storage awaiting restoration.

Probably the best-known Lockheed F-94 variant is the all-rocket-armed F-94C Starfire. (Lockheed Martin)

© 2019, Bryan R. Swopes