Daily Archives: July 1, 2022

1 July 2015

Bell 525 Relentless N525TA makes its first flight, 1 July 2015. (Bell)
Bell 525 Relentless N525TA makes its first flight, 1 July 2015. (Bell Helicopter)

1 July 2015: Bell Helicopter’s new medium transport helicopter, the Model 525 Relentless, N525TA, made its first flight at Bell’s assembly plant in Amarillo, Texas. Test pilots Troy Caudill and Jeff Greenwood were in the cockpit.

The Bell 525 is the first helicopter to use fly-by-wire flight controls. Side stick controllers replace the customary cyclic and collective controls. For the first time for Bell, the 525 uses a five blade main rotor and four blade tail rotor.

Bell 525 Relentless prototype, N525TA.

The helicopter is designed to be operated by two pilots and carry up to 18 passengers. It is powered by two General Electric CT7-2F1 turboshaft engines, each rated at 1,714 shaft horsepower, maximum continuous power, and 1,979 shaft horsepower for takeoff.

N525TA during a test flight.

The Model 525 is the largest helicopter built by Bell. It has an overall length of 64.81 feet (19.75 meters) with rotors turning. The fully-articulated main rotor has a diameter of 54.50 feet (16.62 meters) and rotates counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) The mast tilts forward 5°. The four bladed tail rotor is mounted on the left side of a pylon and rotates clockwise when viewed from the helicopter’s left side. (The advancing blade is below the axis of rotation.) It has a diameter of 10 feet (3.05 meters). The pylon is canted to the left at 15°. The 525 Relentless has a maximum gross weight of 20,000 pounds (9,072 kilograms).

The Model 525 has a maximum cruise speed of 160 knots (184 miles per hour/296 kilometers per hour), and maximum range of 580 nautical miles (1,074 kilometers). At its maximum gross weight the helicopter can hover in ground effect (HIGE) at 10,700 feet (3,261 meters), and out of ground effect (HOGE) at 8,100 feet (2,469 meters).

The prototype Bell 525 Relentless in cruise flight. (Bell Helicopter)
The prototype Bell 525 Relentless, N525TA, in cruise flight. (Bell Helicopter)

N525TA was destroyed during a test flight approximately 30 miles south of Arlington, Texas, 11:48 a.m., 6 July 2016. While conducting a test to determine never exceed speed (VNE) for single-engine flight, the 525 was flying 185 knots (213 miles per hour/343 kilometers per hour) at 1,975 feet (602 meters), the main rotor blades “departed their normal plane of rotation” and struck the nose and tail. The two test pilots on board, Jason Cori Grogan and Erik Allan Boyce, were killed. Both were majors in the United States Marine Corps Reserve, assigned to HMLA 773. Each pilot was a graduate of the U.S. Naval Test Pilot School.

The National Transportation Safety Board (NTSB) determined that the Probable Cause was:

A severe vibration of the helicopter that led to the crew’s inability to maintain sufficient rotor rotation speed (Nr), leading to excessive main rotor blade flapping, subsequent main rotor blade contact with the tail boom, and the resultant in-flight breakup. Contributing to the severity and sustainment of the vibration, which was not predicted during development, were (1) the collective biomechanical feedback and (2) the attitude and heading reference system response, both of which occurred due to the lack of protections in the flight control laws against the sustainment and growth of adverse feedback loops when the 6-hertz airframe vibration initiated. Contributing to the crew’s inability to maintain sufficient Nr in the severe vibration environment were (1) the lack of an automated safeguard in the modified one-engine-inoperative software used during flight testing to exit at a critical Nr threshold and (2) the lack of distinct and unambiguous cues for low Nr.

There are currently three 525s undergoing flight testing. The Federal Aviation Administration certified the Bell 525’s CT7 engines in March 2019.

The number three Bell 525 Relentless prototype, N525BN, first flew 22 April 2016.

© 2020, Bryan R. Swopes

1 July 1954

The last Peacemaker, Convair B-36J-10-CF 52-2827, comes to the end of the assembly line at Fort Worth, Texas.(University of North Texas Libraries)
The last Peacemaker, Convair B-36J-10-CF 52-2827, comes to the end of the assembly line at Fort Worth, Texas, 1 July 1954. (University of North Texas Libraries)

1 July 1954: The final Convair B-36 Peacemaker, B-36J-10-CF 53-2827, a Featherweight III variant, completed assembly at Convair Division of General Dynamics plant at Fort Worth, Texas. The last B-36 built, this was also the very last of the ten-engine very long range heavy bombers in service. It was retired 12 February 1959, and is now in the collection of the Pima Air and Space Museum, Tucson, Arizona.

Convair B-36J 52-2827 is one of 14 Featherweight III high altitude variants. It was built without the six retractable defensive gun turrets of the standard B-36, retaining only the two 20 mm autocannons in the tail. This reduced the crew requirement to 13. The bomber is 162.1 feet (49.4 meters) long with a wingspan of 230.0 feet (70.1 meters) and overall height of 46.8 feet (14.3 meters). The wings had 2° dihedral, an angle of incidence of 3° and -2° twist. The wings’ leading edges were swept aft to 15° 5′. The airplane’s total wing area was 4,772 square feet (443.33 square meters). The B-36J III has an empty weight of 166,165 pounds (75,371 kilograms) and its maximum takeoff weight is 410,000 pounds (185,973 kilograms).

The B-36J has ten engines. There are six air-cooled, turbosupercharged 4,362.494 cubic-inch-displacement (71.488 liter) Pratt & Whitney Wasp Major C6 (R-4360-53) four-row, 28-cylinder radial engines placed inside the wings in a pusher configuration. These had a compression ratio of 6.7:1 and required 115/145 aviation gasoline. The engines incorporated an internal single-stage supercharger, but were also each equipped with two General Electric BH-1 turbosuperchargers. The R-4360-53 had a Normal (continuous power) rating of 2,800 horsepower at 2,600 r.p.m., and Military Power rating of 3,500 horsepower at 2,800 r.p.m., with a 30 minute limit. Its maximum rating was 3,800 horsepower at 2,800 r.p.m. with water/alcohol injection for takeoff, with a 5 minute limit. The engines turned three-bladed Curtiss Electric constant-speed, reversible pitch propellers with a diameter of 19 feet, 0 inches (5.791 meters) through a 0.375:1 gear reduction. The R-4360-53 is 9 feet, 9.00 inches (2.972 meters) long, 4 feet, 7.00 inches (1.397 meters) in diameter, and weighs 4,040 pounds (1,832.5 kilograms).

Four General Electric J47-GE-19 turbojet engines are suspended under the wings outboard of the radial engines in two-engine pods. The J47 is a single-shaft axial-flow turbojet engine with a 12-stage compressor section, 8 combustion chambers, and single-stage turbine. The J47-GE-19 was modified to run on gasoline. It had a continuous power rating of 4,730 pounds of thrust (21.040 kilonewtons) at 7,630 r.p.m., and Military Power rating 5,200 pounds of thrust (23.131 kilonewtons) at 7,950 r.p.m., 30 minute limit (5 minutes for takeoff). The J47-GE 19 was 3 feet, 3 inches (0.991 meters) in diameter, 12 feet, 4 inches (3.658 meters) long, and weighed 2,495 pounds (1,132 kilograms).

Convair B-36J-10-CF 52-2827 at the Pima Air and Space Museum, Tucson, Arizona. (B-36 Peacemaker Museum)
Convair B-36J-10-CF 52-2827 at the Pima Air and Space Museum, Tucson, Arizona. (B-36 Peacemaker Museum)

The B-36J Featherweight III had a cruise speed of 202 knots (232 miles per hour/374 kilometers per hour) and a maximum speed of 375 knots (432 miles per hour (695 kilometers per hour) at 38,000 feet (11,582 meters). The service ceiling was 43,700 feet (13,320 meters). It had a combat radius of 3,465 nautical miles (3,987 statute miles/6,417 kilometers) with a 10,000 pound (4,536 kilogram) bomb load. The maximum ferry range was 8,200 nautical miles (9,436 statute miles/15,186 kilometers).

The B-36J III had a maximum bomb load of 72,000 pounds (32,659 kilograms), carried in four bomb bays. The bomb bay capacity was limited by the physical size of each type weapon, rather than its weight. This ranged from as many as 132 500-pound bombs, 28 2,000-pound bombs, or  4 12,000-pound bombs. It could carry a single 43,600 pound (19,777 kilogram) T-12 Cloudmaker, a conventional explosive earth-penetrating bomb, or several nuclear fission or thermonuclear fusion bombs. By combining the bomb bays, one 41,400 pound (18,779 kilogram) Mk.17 15-megaton thermonuclear bomb could be carried.

Los Alamos Scientific Laboaratory-designed Mk.17 two-stage radiation implosion thermonuclear bomb.

For defense, the B-36J Featherweight III two M24A1 20 mm autocannons in a remotely operated tail turret, with 600 rounds of ammunition per gun.

Between 1946 and 1954, 384 B-36 Peacemakers were built. They were never used in combat. Only five still exist.

Convair B-36J-10-CF Peacemaker, 52-2827, the last B-36 built. (U.S. Air Force)
Convair B-36J-10-CF Peacemaker, 52-2827, the last B-36 built. (U.S. Air Force)

© 2018, Bryan R. Swopes

1 July 1937

Amelia Earhart and Fred Noonan with Mr. Jacobs, at Lae, Territory of New Guinea. (Wichita Eagle)

1 July 1937:  Amelia Earhart and Fred Noonan are delayed another day at Lae, Territory of New Guniea.

“July 1st. ‘Denmark’s a prison,’ and Lae, attractive and unusual as it is, appears to two flyers just as confining, as the Electra is poised for our longest hop, the 2,556 miles to Howland Island in mid-Pacific. The monoplane is weighted with gasoline and oil to capacity. However, a wind blowing the wrong way and threatening clouds conspired to keep her on the ground today. In addition, Fred Noonan has been unable, because of radio difficulties, to set his chronometers. Any lack of knowledge of their fastness and slowness would defeat the accuracy of celestial navigation. Howland is such a small spot in the Pacific that every aid to locating it must be available. Fred and I have worked very hard in the last two days repacking the plane and eliminating everything unessential. We have even discarded as much personal property as we can decently get along without and henceforth propose to travel lighter than ever before. All Fred has is a small tin case which he picked up in Africa. I noted it still rattles, so it cannot be packed very full. Despite our restlessness and disappointment in not getting off this morning, we still retained enough enthusiasm to do some tame exploring of the near-by country.”

—Amelia Earhart

© 2015, Bryan R. Swopes

1 July 1920

First Lieutenant James Harold Doolittle, Air Service, United States Army. “Jimmy” Doolittle is wearing an embroidered Airplane Pilot badge and the World War I Victory Medal ribbon. (U.S. Air Force)

1 July 1920: James Harold Doolittle was commissioned as a second lieutenant, Air Service, United States Army. The commission was accepted 19 September 1920. On the same date, he was promoted to the rank of first lieutenant, Air Service. This was accepted 17 March 1921.

“Jimmy” Doolittle had enlisted as a private, 1st class, in the Aviation Section, Signal Enlisted Reserve Corps, 10 November 1917. He received a commission as a second lieutenant, Aviation Section, Signal Officers’ Reserve Corps, 11 March 1918, and was assigned to active duty the following day.

Following the passage of the National Defense Act of 1920, which established the Air Service, Doolittle’s O.R.C. commission was vacated 19 September 1920, and he was given a commission as a first lieutenant, Air Service, United States Army, retroactive to 1 July 1920.

© 2018, Bryan R. Swopes

1 July 1915

Leutnant Kurt Wintgens, Luftstreitkräfte, wearing the Pour le Mérite (the “Blue Max”) (Postkartenvertrieb W. Sanke)

1 July 1915: German Luftstreitkräfte fighter pilot Leutnant Kurt Wintgens was flying a pre-production Fokker M.5K/MG, number E.5/15, (designated Eindecker III when placed in production), which was equipped with a single fixed, forward-firing machine gun. An interrupter gear driven off the engine stopped the machine gun momentarily as the propeller blades crossed the line of fire. This was known as synchronization.

Leutnant Wintgens' Fokker M.5K/MG Endecker fighter, E.5/15.
Leutnant Wintgens’ Fokker M.5K/MG Eindecker fighter, E.5/15. (Peter M. Grosz Collection)

At approximately 1800 hours, Leutnant Wintgens engaged a French Morane-Saulnier Type L two-place observation airplane east of Lunéville in northeastern France. The French airplane’s observer fired back with a rifle. Eventually, the Morane-Saulnier was struck by bullets in its engine and forced down.

Wintgens is believed to have achieved the first aerial victory using a synchronized machine gun, though because his victim went down inside Allied lines, the victory was not officially credited.

Closeup of a Fokker E.I’s Oberursel U.0 seven cylinder rotary engine, and Stangensteuerung synchronizer gear drive cam/rod unit behind engine crankcase.

The Fokker prototype was armed with an air-cooled 7.9 mm Parabellum MG14 aircraft machine gun made by Deutsche Waffen und Munitionsfabriken Aktien-Gesellschaft. This gun fired ammunition from a cloth belt which was contained inside a metal drum. It had a rate of fire of 600–700 rounds per minute. The synchronization mechanism had been designed by Anton Herman Gerard Fokker, who was also the airplane’s designer.

A Fokker advertisement in Motor, 1917.

The Fokker Aviatik GmbH M.5K/MG Eindecker III was a single-place, single-engine monoplane fighter constructed of a steel tubing fuselage with a doped fabric covering. It had a length of 6.75 meters (22.15 feet), a wingspan of 8.95 meters (29.36 feet) and height of 2.40 meters (7.87 feet). The airplane had an empty weight of 370 kilograms (815.7 pounds) and gross weight of 580 kilograms (1,278.7 pounds).

It was powered by an 11.835 liter (722.2 cubic inch) air-cooled Motorenfabrik Oberursel U.0 seven-cylinder rotary engine which produced 80 Pferdestärke (78.9 horsepower). This engine was a German-built version of the French Société des Moteurs Gnome 7 Lambda engine.

The M.5K/MG had a maximum speed of 130 kilometers per hour (80.8 miles per hour) and a service ceiling of 3,000 meters (9,843 feet). Its range was 200 kilometers (124.3 miles).

Type L
Morane Saulnier Type L (Getty Images/Hulton Archive)

The Aéroplanes Morane-Saulnier Type L was a single-engine two-place monoplane used as a scouting aircraft. The single wing is mounted above to fuselage on struts. This type is called a “parasol wing.” The airplane is 6.88 meters (22.57 feet) long with a wingspan of 11.20 meters (36.75 feet) long and height of 3.93 meters (12.89 feet). Its empty weight is 393 kilograms (866 pounds) and gross weight is 677.5 kilograms (1,494 pounds).

The Type L was powered by a 10.91 liter (665.79 cubic inch) Société des Moteurs Le Rhône 9C nine-cylinder rotary engine which produced 83 horsepower at 1,285 r.p.m.

The Morane Salunier Type L had a maximum speed of 125 kilometers per hour (78 miles per hour). It could be armed with one .303-caliber Lewis light machine gun on a flexible mount.

Kurt Hermann Fritz Karl Wintgens was born 1 August 1894 at Neustadt in Oberschlesien, Prussia. He was the son of Lieutenant Paul Wingens, a cavlary officer, and Martha gb. Bohlmann.

Wintgens entered a military academy as an officer cadet in 1913, but with the outbreak of World War I, he was appointed a lieutenant and sent to the Eastern Front. He earned the Iron Cross.

Leutnant Wintgens was transferred to the Luftstreitkräfte as an observer, but then trained as a pilot.

Wintgens was officially credited with 19 aerial victories, with three more unconfirmed. After his eighth victory he was awarded “the Blue Max,” (Pour le Mérite).

Kurt Wintgens was shot down near Viller-Carbonnel, Somme, France, 25 September 1916. He was killed in the crash.

© 2018, Bryan R. Swopes