Category Archives: Aviation

12 December 1991: In which a Boeing 747 goes supersonic.

Evergreen International Airlines’ Boeing 747-121, N475EV, photographed at Hellinikon International Airport, Athens, Greece, 1 January 1991. The airliner has just been converted to a freighter. (Savvas Garozis)

12 December 1991: A Boeing 747 freighter operated by Evergreen International Airlines was en route from New York’s John F. Kennedy International Airport (JFK) to Tokyo, Japan, with an intermediate stop at Anchorage International Airport (ANC), Alaska, U.S.A. The 747 had a flight crew of six and no passengers.

At about 5:20 a.m., Central Standard Time (11:15 UTC), the 747 was cruising at Flight Level 310 (31,000 feet/9,449 meters) near Nakina, a small village approximately 150 nautical miles (173 statute miles/278 kilometers) northeast of Thunder Bay, Ontario, Canada.

The flight crew observed that the airplane’s Inertial Navigation System (INS) FAIL warning lights were on. Checking their instruments, they found that the 747 had entered a 90° right bank and was in a 30°–35° descent. It was rapidly losing altitude and gaining speed.

Before the crew could recover, N475EV had lost over 10,000 feet (3,048 meters) and reportedly reached 0.98 Mach in its dive. After regaining control of the 747, the crew made an emergency landing at Duluth, Minnesota, at 5:43 a.m., Central Standard Time.

On inspection, a large hole, approximately 3 feet × 15 feet (0.9 × 4.5 meters), was found in the leading edge of the right wing, inboard of the Number 3 engine. Three sheet metal panels had torn off, then struck the right horizontal stabilizer, denting its leading edge. On landing, a flap on the left wing fell off.

According to an article in the Seattle Times, an investigator for the National Transportation Safety Board confirmed that the 747 had exceeded its design speed of 0.92 Mach, but as the Flight Data Recorder had not yet been analyzed, “. . . he could not confirm reports that it reached Mach 1.25. . . .”

The Seattle Times reported the incident:

Dive! 747 In Unexplained Incident — Canada Investigating Automatic Pilot Controls After Near-Supersonic Scare

Canadian authorities are scrutinizing the automatic flight controls of a Boeing 747-100 jumbo jet after the plane inexplicably rolled 90 degrees to its right and dove two miles at near-supersonic speed.

The incident occurred last Thursday as the plane, a passenger jetliner converted to a freighter, was cruising at 31,000 feet above Nakina, Ont., on a New York-to-Anchorage flight. The jet is owned and operated by Evergreen International Airlines, based in McMinnville, Ore.

The pilots righted the craft at 22,500 feet, then made a safe emergency landing at Duluth, Minn.

None of the six Evergreen employees on board, including the three-member flight crew, was injured, according to Dave McNair, investigator for the Transporation Safety Board of Canada.

McNair said the jumbo jet’s four turbofan engines functioned properly. He said a broad investigation would take several months and will include an examination of the sophisticated computers designed to fly the plane automatically for most of the flight.

“What we’ll be doing is looking at the entire autopilot logic and any associated logic,” he said.

At some point during the incident, three large panels beneath the leading edge of the right wing tore off, leaving a 3-by-15-foot hole on the forward, inboard section of the right wing.

The panels damaged the right flap (located on the trailing edge of the wing) and dented the right-side forward edge of the horizontal tail section, according to McNair and Boeing spokesman Chris Villiers. Upon landing, part of the left flap came off, as well, Villiers said.

Authorities said it was unclear whether the panels from the right wing came loose first and, thus, precipitated the roll and dive, or if the parts shook loose as the plane careened at a 30- to 35-degree angle of descent – more than three times a normal rate of descent. McNair said age of the 21-year-old aircraft is not believed to be a factor.

The 747-100 is designed to withstand a top speed of Mach 0.92 – nine-tenths the speed of sound, or more than 500 miles per hour at that altitude. McNair said the plane reached speeds faster than that during the dive, but he could not confirm reports that it reached Mach 1.25, because precise information from the flight-data recorder was not immediately available.

Tacoma aviation safety expert John Nance, a former 747 pilot, said it is plausible that the plane would begin to disintegrate once the speed surpassed its so-called “design limit.”

Nance described modern jetliners as “metallic eggshells, very strong when used exactly as they are designed to be used; very weak when not.”

The Evergreen incident occurred on the same day that whistleblower Darrell Smith, a former Boeing 747 computer analyst, made public an internal Boeing audit outlining major flaws in a software program used by a computer that senses the position of key moving parts on the Boeing 747-400, an advanced version of the 747-100.

Boeing officials said the computer Smith reviewed on the 747-400 doesn’t exist on the 747-100. The Evergreen plane was one of the first delivered from Boeing’s Everett plant in July 1970 to Pan Am.

Even so, Smith’s allegations and the Evergreen roll-and-dive add to a string of instances over the past two years in which alleged or apparent flaws in Boeing technology have become part of a heated air-safety debate:

— Last May, an electronically controlled engine-braking device, called a thrust reverser, inexplicably deployed as a Lauda Air 767-300ER jetliner climbed away from Bangkok, instantly flipping the plane into a supersonic crash dive. All 223 on board were killed.

Authorities still do not fully understand how a stray electrical signal, vibration or some other phenomena could have deployed the reverser. Meanwhile, Boeing has steadfastly declined to answer a call by the National Transportation Safety Board to upgrade pilot instructions on what to do if a reverser warning light illuminates in the cockpit during flight. Electronic reversers are used on all Boeing jetliners delivered in the past few years – nearly 1,700 planes all told.

— Last February, Hoot Gibson, a former Trans World Airlines pilot revealed nine complaints from pilots citing major control problems on Boeing 727 jets apparently related to a random, mysterious malfunction of the autopilot computer.

Gibson has waged a 12-year battle with the NTSB and Boeing to clear his name of allegations that he caused a TWA 727 to careen dangerously from a high altitude by attempting to improperly manipulate the controls to enhance the plane’s performance. Gibson, who wrestled back control of the plane at the last minute, maintains that a flaw in the autopilot triggered the dive.

— In April 1990, the NTSB, relying on Boeing technical data and analysis, ruled that the pilots of USAir Flight 5050 made the wrong decision to abort the takeoff of a 737-400 from New York’s LaGuardia airport on Sept. 20, 1989. The pilot decided to abort takeoff when the plane lurched left because the rudder was stuck full left. (The rudder, the upright section of the tail, is supposed to be in neutral for takeoff.)

The NTSB ruled that the pilots should have noticed the stuck rudder and, in any case, should have followed through with the takeoff, even with the stuck rudder. Two passengers were killed as the plane ditched into Bowery Bay.

The ruling upset pilots who felt little credence was given to scores of reports of problems with a new type “rudder trim.” Reports from pilots said it was moving the rudder without being commanded to do so.

Copyright © 1991 Seattle Times Company, All Rights Reserved.

The Seattle Times, 19 December 1991

A year later, the Chicago Tribune reported,

Tom Cole, a spokesman at Boeing Commercial Airplane Co., said original flight tests of 747s conducted in 1969 and 1970 took 747-100 models to speeds of Mach 0.99.

In addition, Boeing knows one case in which a 747 operated by Evergreen International made an emergency descent at speeds that exceeded Mach 1, he said.

Chicago Tribune, 20 December 1992

Following the December 1991 incident, N475EV was repaired and returned to service.

This was not the first time that 19638 had been damaged:

Boeing 747 19638 (RA003) with a nose boom during flight testing, 1969. (Jeff Ohlston/Boeing)

Boeing 747-121, serial number 19638, line number RA003, had made its first flight on 11 July 1969. Boeing used the aircraft for flight and certification testing. On completion of these tests, it was to be flown to Boeing’s Renton plant to be modified to production standards, refurbished, and then delivered to the new owner, Pan American World Airways.

While landing on Runway 15 at Renton Airport, at 11:11 a.m., 13 December 1969, 19638 struck an embankment about 20 feet (6 meters) short of the runway. None the 11 Boeing employees on board were injured. The Number 3 and 4 engines were damaged and caught fire. The right landing gear was pulled backward, but held to the wing by linkages and actuators. The flaps on the right wing were damaged. The right wing’s lower surface was punctured. The fires were quickly extinguished.

A video clip of the accident is available on YouTube:

N732PA was repaired and finally delivered to Pan American on 13 July 1970. The 747 was christened Clipper Storm King. (It was later renamed Ocean Telegraph.)

Pan Am operated the airliner for nearly 21 years. It was sold to Evergreen International Airlines, 1 July 1991, and converted to an air freighter at Evergreen’s maintenance depot at Marana, Arizona. It was re-registered N475EV.

Pan American World Airways’ Boeing 747-121, N732PA, Clipper Storm King. (Aldo Bidini via Wikimedia)

Evergreen flew N475EV until it was sold to Tower Air, 13 September 1994. Under new ownership, the Boeing 747 was again re-registered, to N615FF.

The FAA registered the 747 to Kalitta Equipment LLC, 3 August 2000. The N-number did not change. The airplane’s registration was canceled 30 June 2017.

© 2018, Bryan R. Swopes

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12 December 1957

Major Adrian E. Drew, U.S. Air Force, 1920–1985. (Photograph courtesy of Neil Corbett, Test & Research Pilots, Flight Test Engineers)

12 December 1957: Major Adrian Eason Drew, U.S. Air Force, commanding officer, 481st Fighter Bomber Squadron, 27th Fighter Bomber Wing, Tactical Air Command, set a new Fédération Aéronautique Internationale (FAI) absolute speed record over the 15/25 kilometer course at Edwards Air Force Base, California.¹ Major Drew flew a modified McDonnell F-101A-5-MC Voodoo, serial number 53-2426.

The Voodoo, the ninth production F-101A, had been bailed to Pratt & Whitney by the Air Force to test a new J57-P-55 afterburning turbojet engine intended for the F-101B Voodoo, and it was redesignated JF-101A. The new engine produced 16,000 pounds of thrust with afterburner. The modified aircraft had longer jet exhaust tubes, and air scoops were installed in the belly to provide additional cooling air for the afterburners.

McDonnell JF-101A Voodoo 53-2426, takes off at Edwards Air Force Base on Operation Fire Wall, 12 December 1957. (U.S. Air Force)
McDonnell JF-101A Voodoo 53-2426, takes off at Edwards Air Force Base on Operation Fire Wall, 12 December 1957. (U.S. Air Force)
Thompson Trophy. (NASM)

At 39,000 feet (11,887 meters), Major Drew accelerated for 65 miles (105 kilometers) before entering the 10.1 statute mile (16.25 kilometers) course. He made one pass in each direction. Actual time on course, each way, was 29.8 seconds. The official average speed for the two passes is 1,943.5 kilometers per hour (1,207.64 miles per hour). Although the air temperature was -79 °F. (-62 °C.), frictional heating brought the Voodoo’s skin temperature to 190 °F. (88 °C.), high enough to blister the airplane’s paint.

Major Drew was awarded the Distinguished Flying Cross and the Thompson Trophy for 1957.

Major Adrian E. Drew, 481st Fighter Bomber Squadron, 27th Fighter Bomber Wing, U.S. Air Force, at Edwards AFB, 12 December 1957. (U.S. Air Force via Jet Pilot Overseas)
Major Adrian E. Drew, 481st Fighter Bomber Squadron, 27th Fighter Bomber Wing, U.S. Air Force, at Edwards AFB, 12 December 1957. [TDiA speculates that the man on the right is Major Drew’s younger brother, Bobby R. Drew.] (U.S. Air Force via Jet Pilot Overseas)
Adrian Eason Drew was born 8 October 1920 in Georgia, the first of six children of John Robert Drew, a farmer, and Ada Elma Eason Drew.

After one year of college, Adrian Drew enlisted as a private in the U.S. Army Air Corps, 31 March 1942, at Fort McClellan, Alabama. He was 5 feet, 8 inches (1.73 meters) tall and weighed 143 pounds (64.9 kilograms).

On 14 November 1942, Drew married Miss Sarah B. Kaylor in Pinellas County, Florida. They would have three daughters, Nancy, Bonnie and Jo Anne.

Colonel Drew was a combat pilot during World War II, the Korean War and the Vietnam War. He commanded the 309th Strategic Fighter Squadron from January to October 1955, flying the Republic F-84 Thunderjet. In August 1957, he became the first commanding officer of the 481st Fighter Bomber Squadron at Bergstom Air Force Base,  Austin, Texas. Lieutenant Colonel Drew commanded the 354th Tactical Fighter Squadron at George Air Force Base, California, from 1962 to 1964, flying the Republic F-105D Thunderchief, and briefly commanded the 355th Tactical Fighter Wing.

Two weeks before a scheduled promotion to Brigadier General, Colonel Drew suffered a major heart attack and was forced to retire from the Air Force. He died 27 July 1985 at the age of 64 years. He was buried at Shawnee View Gardens Cemetery, Cumming, Georgia.

McDonnell JF-101A Voodoo 53-2426, holder of the World Absolute Speed Record, 1957. (U.S. Air Force)

The McDonnell F-101 Voodoo was originally designed as a single-seat, twin-engine long range bomber escort, or “penetration fighter” for the Strategic Air Command, but was developed as a fighter bomber and reconnaissance airplane. The Voodoo first flew 29 September 1954, and the first F-101A was delivered to the Air Force 2 May 1957.

The F-101A was 67 feet, 5 inches (20.549 meters) long with a wingspan of 39 feet, 8 inches (12.090 meters). It was 18 feet (5.486 meters) high. The Voodoo weighed 24,970 pounds (11,245 kilograms) empty and had a maximum takeoff weight of 50,000 pounds (22,680 kilograms).

The standard F-101A was equipped with two Pratt and Whitney J57-P-13 afterburning turbojet engines. The J57 was a two-spool axial-flow turbojet which had a 16-stage compressor (9 low- and 7 high-pressure stages), and a 3-stage turbine (1 high- and 2 low-pressure stages). The J57-P-13 was rated at 10,200 pounds of thrust (45.37, and 15,800 pounds (70.28 kilonewtons) with afterburner.

The J57-P-55 engines installed in the JF-101A were rated at 10,700 pounds of thrust (49.60 kilonewtons), and 16,900 pounds (75.18 kilonewtons) with afterburner. They were 20 feet,  11.93 inches (6.399 meters) long, 3 feet, 4.5 inches (1.029 meters) in diameter, and weighed 5,215 pounds (2,365 kilograms).

The maximum speed of the F-101A was 1,009 miles per hour (1,624 kilometers per hour) at 35,000 feet (10,668 meters). Its service ceiling was 55,800 feet (17,008 meters). It carried 2,341 gallons (8,862 liters) of fuel internally. With external tanks, the fighter bomber had a maximum range of 2,925 miles (4,707.3 kilometers).

The F-101A was armed with four 20mm Pontiac M39 single-barreled revolver cannon, with 200 rounds per gun. It could carry a Mark 28 bomb on a centerline mount.

McDonnell JF-101A Voodoo 53-2426 is on static display at Cannon Air Force Base, New Mexico.

McDonnell JF-101A Voodoo 53-2426, FAI World Speed Record Holder and Thompson Trophy winner, Operation Fire Wall, landing at Edwards Air Force Base, 12 December 1957. (U.S. Air Force)
McDonnell JF-101A Voodoo 53-2426, FAI World Speed Record Holder and Thompson Trophy winner, Operation Fire Wall, landing at Edwards Air Force Base, 12 December 1957. (U.S. Air Force)

A McDonnell Aircraft Corporation film about Operations Sun Run and Fire Wall is available of YouTube:

¹ FAI Record File Number 9064

© 2017, Bryan R. Swopes

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12 December 1953

Bell X-1A 48-1384 in flight. The frost band on the fuselage shows the location of the cryogenic propellant tank. (U.S. Air Force)

12 December 1953: On its tenth flight, U.S. Air Force test pilot Major Chuck Yeager flew the Bell X-1A rocket plane to Mach 2.44 (1,621 miles per hour/2,609 kilometers per hour) at 74,700 feet (22,769 meters), faster than anyone had flown before.

After the rocket engine was shut down, the X-1A tumbled out of control—”divergent in three axes” in test pilot speak—and fell out of the sky. It dropped nearly 50,000 feet (15,240 meters) in 70 seconds. Yeager was exposed to accelerations of +8 to -1.5 g’s. The motion was so violent that Yeager cracked the rocketplane’s canopy with his flight helmet.

Yeager was finally able to recover by 30,000 feet (9,144 meters) and landed safely at Edwards Air Force Base.

Yeager later remarked that if the X-1A had an ejection seat he would have used it.

Bell Aircraft Corporation  engineers had warned Yeager not to exceed Mach 2.3.

Major Charles E. Yeager, U.S. Air Force, seated in the cockpit of the Bell X-1A, 48-1384, circa 1953. (U.S. Air Force)

The following is from Major Charles E. Yeager’s official post-flight report:

“After a normal drop at 31,000 feet, chambers #4, #2, and #1 were ignited and [the] airplane was accelerated up to .8 Mach number. A flight path was formed holding .8 Mach number up to 43,000 feet where chamber #3 was ignited and the airplane accelerated in level flight to 1.1 Mach number. A climb was again started passing through 50,000 feet at 1.1 Mach number, 60,000 feet at 1.2 Mach number and a push-over was started at 62,000 feet. The top of the round-out occurred at 76,000 feet and 1.9 Mach number. The airplane was accelerated in level flight up to 2.4 [2.535 indicated] Mach number where all of the rocket chambers were cut. The flight path was very normal and nothing uneventful [sic] happened up to this point. After the engine was cut, the airplane went into a Dutch roll for approximately 2 oscillations and then started rolling to the right at a very rapid rate of roll. Full aileron and opposite rudder were applied with no effect on the rate of roll of the airplane. After approximately 8 to 10 complete rolls, the airplane stopped rolling in the inverted position and after approximately one-half of one second started rolling to the left at a rate in excess of 360 degrees per second, estimated by the pilot. At this point the pilot was completely disoriented and was not sure what maneuvers the airplane went through following the high rates of roll. Several very high ‘g’ loads both positive and negative and side loads were felt by the pilot. At one point during a negative ‘g’ load, the pilot felt the inner liner of the canopy break as the top of his pressure suit helmet came in contact with it. The first maneuver recognized by the pilot was an inverted spin at approximately 33,000 feet. The airplane then fell off into the normal spin from which the pilot recovered at 25,000 feet.”

Flight test data from Yeager's 12 December 1953 flight superimposed over a photograph of the bell X-1A. (NASA)
Flight test data from Yeager’s 12 December 1953 flight superimposed over a photograph of the Bell X-1A. (NASA)

The following is a transcript of radio transmissions during the flight:

Yeager: Illegible [inaudible]—gasping—I’m down to 25,000 over Tehachapi. Don’t know
whether I can get back to the base or not.
Chase (Ridley): At 25,000 feet, Chuck?
Yeager: Can’t say much more, I got to (blurry—save myself).
Yeager: I’m—(illegible)—(Christ!)
Chase (Ridley): What say, Chuck?
Yeager: I say I don’t know if I tore anything up or not but Christ!
Chase (Murray): Tell us where you are if you can.
Yeager: I think I can get back to the base okay, Jack. Boy, I’m not going to do that any more.
Chase (Murray): Try to tell us where you are, Chuck.
Yeager: I’m (gasping)…I’ll tell you in a minute. I got 1800 lbs [nitrogen] source pressure.
Yeager: I don’t think you’ll have to run a structure demonstration on this damned thing!
Chase (Murray): Chuck from Murray, if you can give me altitude and heading, I’ll try to check you from outside.
Yeager: Be down at 18,000 feet. I’m about—I’ll be over the base at about 15,000 feet in a minute.
Chase (Murray): Yes, sir.
Yeager: Those guys were so right!
Yeager: Source pressure is still 15 seconds, I’m getting OK now.
Yeager: I got all the oscillograph data switches off. 4 fps camera off, it’s okay.
Bell Truck: Jettison and vent your tanks.
Yeager: I have already jettisoned. Now I’m venting both lox and fuel. Leaving hydrogen peroxide alone.
Bell Truck: Roger.
Yeager: I cut it, I got—in real bad trouble up there.
Yeager: Over the base right now, Kit, at 14,500 feet.
Chase (Murray): I have you.

A North American F-86E-10-NA Sabre chase plane, 51-2848, follows the Bell X-1A as it glides toward Rogers Dry Lake. (NASA)
A North American F-86E-10-NA Sabre chase plane, 51-2848, follows the Bell X-1A as it glides toward Rogers Dry Lake. (NASA)

In his autobiography, Always Another Dawn, NACA test pilot Albert Scott Crossfield wrote:

Probably no other pilot could have come through that experience alive. Much later I asked Yeager, as a matter of professional interest, exactly how he regained control of the ship. He was vague in his reply, but he said he thought that after he reached the thick atmosphere, he had deliberately put the ship into a spin.

“A spin is something I know how to get out of,” he said. “That other business— the tumble—there is no way to figure that out.”

. . . Yeager received many accolades. I didn’t begrudge him one of them. If ever a pilot deserved praise for a job well done, it was Yeager. After that X-1A episode, he never flew a rocketplane again.

Always Another Dawn: The Story of a Rocket Test Pilot, by A. Scott Crossfield with Clay Blair, Jr., The World Publishing Company, Cleveland and New York, Chapter 19 at Pages 183–184.  

Bell X-1A 48-1384 (U.S. Air Force)

The Bell X-1A, 48-1384, was an experimental rocket-powered high-speed, high-altitude research aircraft. It was one of four second-generation X-1s (including the X-1B, X-1D and X-1E), specifically designed to investigate dynamic stability at speeds in excess of Mach 2 and altitudes greater than 90,000 feet. It was a mid-wing monoplane with retractable tricycle landing gear. The airplane was 35 feet, 6.58 inches (10.835 meters) long with a wingspan of 30 feet, 6 inches (9.296 meters) and overall height of 10 feet, 2.37 inches (3.261 meters). The wheelbase, measured from the nose wheel axle to the main wheel axle, was  13 feet, 5.13 inches. (4.093 meters). The main wheel tread was 4 feet, 3 inches (1.295 meters). The X-1A design gross weight was 10,668 pounds (4,839 kilograms).

The X-1A was powered by a single Reaction Motors XLR11-RM-5 rocket engine with four independent combustion chambers. The XLR11 was fueled with ethyl alcohol and liquid oxygen. It produced 6,000 pounds of thrust (26.689 kilonewtons).

The Bell X-1A made its first flight 14 February 1953 with Bell test pilot Jean Ziegler in the cockpit. It reached its highest speed, Mach 2.44 on Flight 10. Its highest altitude was 90,440 feet (27,566 meters) on its 24th flight. On 8 August 1955, while still on board its B-50 drop ship, the X-1A suffered an external explosion. The rocketplane was jettisoned and destroyed when it hit the desert floor.

© 2016, Bryan R. Swopes

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11 December 1959

Lieutenant General Joseph H. Moore (1914–2007)
Lieutenant General Joseph H. Moore, United States Air Force

11 December 1959: Brigadier General Joseph H. Moore, U.S. Air Force, Wing Commander, 4th Tactical Fighter Wing at Seymour Johnson Air Force Base, North Carolina, set a Fédération Aéronautique Internationale (FAI) World Speed Record when he flew a Republic F-105B-20-RE Thunderchief, serial number 57-5812, over a closed 100-kilometer (62.137 miles) closed course at Edwards Air Force Base, California. The Thunderchief averaged 1,878.67 kilometers per hour (1,167.35 miles per hour).¹ General Moore’s fighter bomber was a standard production aircraft and it was armed with a full load of ammunition for the M61 cannon.

FAI Record File Num #8873 [Direct Link]
Status: ratified – retired by changes of the sporting code
Region: World
Class: C (Powered Aeroplanes)
Sub-Class: C-1 (Landplanes)
Category: Not applicable
Group: 3 : turbo-jet
Type of record: Speed over a closed circuit of 100 km without payload
Performance: 1 878.67 km/h
Date: 1959-12-11
Course/Location: Edwards AFB, CA (USA)
Claimant Joseph H. Moore (USA)
Aeroplane: Republic F-105B
Engine: 1 Pratt & Whitney J-75

Republic F-105B-1-RE Thunderchief 54-102. (U.S. Air Force)
Republic F-105B-1-RE Thunderchief 54-102. (U.S. Air Force)

The F-105 was the largest single-seat, single-engine combat aircraft in history. It was designed as a tactical nuclear strike aircraft and fighter-bomber. The fuselage of the F-105B incorporated the “area rule” which gave the Thunderchief its characteristic “wasp waist” shape. The Thunderchief was 63 feet, 1 inch (19.228 meters) long with a wingspan of 34 feet, 11 inches (10.643 meters). It was 19 feet, 8 inches high (5.994 meters). 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). The F-105 had an empty weight of 25,855 pounds (11,728 kilograms) and a maximum takeoff weight of 50,000 pounds (22,680 kilograms).

Brigadier General Joseph H. Moore with a Republic F-105 Thunderchief.
Brigadier General Joseph H. Moore with a Republic F-105 Thunderchief.

Early production F-105Bs had the Pratt & Whitney J75-P-5 axial-flow turbojet engine. Beginning with the Block 20 aircraft, the more powerful J75-P-19 was installed. The -19 engine was retrofitted to the earlier aircraft. The Thunderchief was powered by one Pratt & Whitney J75-P-19W engine. The J75 is a two-spool axial-flow afterburning turbojet with water injection. It has a 15-stage compressor section (8 low- and and 7 high-pressure stages) and 3-stage turbine section (1 high- and 2 low-pressure stages.) The J75-P-19W is rated at 14,300 pounds of thrust (63.61 kilonewtons), continuous power; 16,100 pounds (71.62 kilonewtons), Military Power (30-minute limit); and Maximum Power rating of 24,500 pounds (108.98 kilonewtons) with afterburner (15-minute limit). The engine could produce 26,500 pounds of thrust (117.88 kilonewtons) with water injection, for takeoff. The J75-P-19W is 21 feet, 7.3 inches (6.586 meters) long, 3 feet, 7.0 inches (1.092 meters) in diameter, and weighs 5,960 pounds (2,703 kilograms).

Armament consisted of one 20 mm General Electric M61 Vulcan six-barreled Gatling gun with 1,080 rounds of ammunition. It had an internal bomb bay and could carry bombs, missiles or fuel tanks on under wing and centerline hardpoints. The maximum bomb load consisted of four 750-pound (340 kilogram) bombs. For tactical nuclear strike missions, the F-105B could carry one Mk-28 “special store” in the internal bomb bay.

The F-105B had a maximum speed of 737 knots (848 miles/1,364 kilometers per hour) at Sea Level, and 1,204 knots (1,386 miles per hour/2,230 kilometers per hour) at 35,000 feet (10,668 meters). The service ceiling was 45,700 feet (13,929 meters). Maximum range was 2,006 nautical miles (2,308 statute miles/3,715 kilometers).

Republic Aircraft Corporation built 833 Thunderchiefs for the U.S. Air Force. 75 of those were F-105Bs. 372 F-105s were lost to enemy action in South East Asia.

Republic F-105B-20-RE Thunderchief 57-5812 served with the 119th Tactical Fighter Squadron, New Jersey Air National Guard, and was later assigned to the 466th Tactical Fighter Squadron, 508th Tactical Fighter Wing at Hill Air Force Base, Utah. One source indicates that the the record-setting F-105B was used as a battle damage repair trainer at McClellan Air Force Base, Sacramento, California, from October 1980.

Six F-105B-10-REs (6 of 9 block 10 aircraft built) of General Moore's 4th Tactical Fighter Wing parked on the ramp. The stripes on the nose and vertical fin are green. Aircraft are (nearest to farthest) S/N 57-5779, -5780, -5782, -5784, -5781, -5778. (U.S. Air Force photo)
Six F-105B-10-REs (6 of 9 block 10 aircraft built) of General Moore’s 4th Tactical Fighter Wing parked on the ramp. The stripes on the nose and vertical fin are green. Aircraft are (nearest to farthest) 57-5779, -5780, -5782, -5784, -5781, -5778. (U.S. Air Force)
Three Republic F-105B-20-RE Thunderchiefs, serial numbers 57-5815, 57-5807 and 57-5822, begin their takeoff roll. This is the same block number as the F-105B flown by General Moore for the FAI World Speed Record. (U.S. Air Force)
Three Republic F-105B-20-RE Thunderchiefs, serial numbers 57-5815, 57-5807 and 57-5822, begin their takeoff roll. These are from the same production block as the F-105B flown by General Moore for the FAI World Speed Record. (U.S. Air Force)
Republic F-105B-20-RE Thunderchief 57-5812, assigned to the 466th Tactical Fighter Squadron. (Million Monkey Theater)
The World Speed Record holder, Republic F-105B-20-RE Thunderchief 57-5812, assigned to the 466th Tactical Fighter Squadron, 508th Tactical Fighter Wing, Hill Air Force Base, Utah. (Million Monkey Theater)

¹ Many sources cite General Moore’s World Record Speed for the 100-kilometer closed course at 1,216.48 miles per hour (1,957.745 kilometers per hour). The FAI’s official web site gives General Moore’s speed as 1,878.67 kilometers per hour (1,167.35 miles per hour). (See above.) Also, many sources (including General Moore’s official Air Force biography) state that General Moore won the Bendix Trophy for this flight. The Bendix Trophy was awarded to the winner of an annual West-to-East transcontinental air race. The Smithsonian Institution indicates that the Bendix Trophy was not awarded for the years 1958, 1959 or 1960.

© 2018, Bryan R. Swopes

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11 December 1951

Test pilot William R. Murray at the control of Kaman K-225, Bu. No. 125477, with a Boeing 502-2 gas turbine engine installed, hovering out of ground effect. (U.S. Navy)

11 December 1951: The first helicopter powered by a gas turbine engine made its first flight at the Kaman Aircraft Company plant at Bloomfield, Connecticut. Using a K-225 tandem rotor helicopter delivered to the U.S. Navy in 1949, Bureau of Aeronautics serial number (“Bu. No.”) 125477, Kaman replaced the 220 horsepower Lycoming O-435-A2 reciprocating engine with a Boeing 502-2E turboshaft engine. This engine could produce 175 continuous horsepower at 2,900 r.p.m. at Sea Level, less than the piston engine it replaced, but it also weighed considerably less.

K-225 Bu. No. 125477 was the first helicopter to perform an intentional loop, when it was delivered to the Navy at NATC Patuxent River by factory test pilot William R. Murray. It was placed in storage at Bradley Field, Windsor Locks, Connecticut until 1957. The gas turbine had been removed. When the helicopter was transferred to the Smithsonian Institution in 1957, a similar-appearing Boeing YT-50-BO-2 gas turbine engine was installed.

The K-225 was a two-place, single-engine helicopter using Kaman’s unique system of counter-rotating, intermeshing rotors (“synchropter”). Each rotor cancelled the torque reaction of the other, eliminating the need for a tail rotor. In a conventional single-rotor helicopter, up to 30% of the engine power is required to drive the tail rotor. With the counter-rotating design, the total engine power is available for lift and thrust.

K-225 Bu. No. 125477 is 22 feet, 5 inches (6.83 meters) long. Each rotor has a diameter of 38 feet (11.58 meters). It stands 11 feet, 6 inches (3.51 meters) high. The helicopter has an empty weight of 1,800 pounds (816 kilograms) and a maximum gross weight of 2,700 pounds (1,225 kilograms). It is a slow helicopter, with a never-exceed (VNE) limit of 70 miles per hour (112.7 kilometers per hour). This historic helicopter is on display at the Smithsonian Institution National Air and Space Museum, Steven F. Udvar-Hazy Center in Chantilly, Virginia.

Kaman K-225, Bu. No. 125477, the first gas turbine-powered helicopter, at the Vertical Flight Gallery, Steven F. Udvar-Hazy Center, Smithsonian Institution National Air and Space Museum, Chantilly, Virginia. (NASM)
Kaman K-225, Bu. No. 125477, the first gas turbine-powered helicopter, at the Vertical Flight Gallery, Steven F. Udvar-Hazy Center, Smithsonian Institution National Air and Space Museum, Chantilly, Virginia. (NASM)

© 2016, Bryan R. Swopes

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