Daily Archives: February 16, 2024

16 February 1967

Wilfried von Englehardt tests the Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA in an out-of-ground effect hover, with engine cowlings removed, 16 February 1967. (Eurocopter)
Wilfried von Engelhardt tests the prototype Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA, in an out-of-ground effect hover with engine cowlings removed, 16 February 1967. (Airbus Helicopters Deutschland GmbH)
Wilfried von Englehardt (Académie de l’Air et de l’Espace)
Wilfried von Engelhardt (Académie de l’Air et de l’Espace)

16 February 1967: At Ottobrun, Germany, test pilot Wilfried von Engelhardt made the first flight of the Bölkow-Entwicklungen KG Bo-105 prototype V-2, D-HECA, a twin-engine, rigid rotor helicopter. Baron von Engelhardt took off at 5:04 p.m. The flight lasted 20 minutes. D-HECA was the second prototype. The first one was destroyed by ground resonance during pre-flight testing.

Messerschmitt AG merged with Bölkow-Entwicklungen KG in June 1968, becoming  Messerschmitt-Bölkow. The following year, the new company merged with Blohm & Voss to become Messerschmitt-Bölkow-Blohm KG, or MBB. The Bo-105 A entered production in 1970. A number of civil and military variants followed.

The Bo-105 is a 5-place light helicopter powered by two turboshaft engines. It has a four-bladed rigid (or hingeless) main rotor. This gives it a high degree of maneuverability, and it is capable of performing aerobatic maneuvers. The two-bladed tail rotor is mounted high on a pylon and gives exceptional ground clearance for a helicopter of this size. There are two “clam shell” doors located at the rear of the cabin section, giving access to a large flat floor. The helicopter has been widely used by military, law enforcement and as an air ambulance.

Messerschmitt-Bölkow-Blohm Bo-105 V-2, D-HECA. (Eurocopter)
Bölkow-Entwicklungen KG prototype Bo-105 V-2, D-HECA, during flight testing. (Airbus Helicopters Deutschland GmbH )

The Bo-105 is 11,86 meters (38 feet, 10.9 inches ) long with rotors turning. The fuselage is 8,81 meters (28 feet, 10.9 inches) long, with a maximum width of 1,58 meters (5 feet, 2.2 inches). The helicopter’s overall height is 3.00 meters (9 feet, 10 inches). The helicopter has an empty weight of approximately 1,276 kilograms (2,813 pounds), depending on installed equipment, and maximum takeoff weight of 2,100–2,500 kilograms (5,512 pounds), depending on variant.

The diameter of the main rotor is 9,84 meters (32 feet, 3.4 inches). The main rotor follows the American practice of turning counter-clockwise as seen from above. (The advancing blade is on the right.) It operates at 416–433 r.p.m. (361–467 r.p.m. in autorotation). The tail rotor diameter is 1,90 meters (6 feet, 2.8 inches). It turns clockwise as seen from the helicopter’s left side. (The advancing blade is below the axis of rotation.)

Three-view illustration of the Messerschmitt-Bölkow-Blohm Bo-105 LS (lengthened cabin section). (Nordic Helicopters)

The prototype was powered by two Allison 250-C18 turboshaft engines, with increasingly more powerful 250-C20, -C20B and C-28C engines being added through the production run. The Allison 250-C18 is a 2-spool, reverse-flow, gas turbine engine with a 6-stage axial-flow, 1-stage centrifugal-flow, compressor section, and a 4-stage axial-flow turbine (2-stage gas producer, and 2-stage power turbine). The 250-C18 is rated at 317 shaft horsepower at 51,600 r.p.m., N1 (6,000 r.p.m. N2).

The helicopter’s cruise speed is 127 miles per hour (204 kilometers per hour) and maximum speed (VNE) is 135 knots (155 miles per hour/250 kilometers per hour) at Sea Level. The service ceiling is 17,000 feet (5,180 meters). The Bo-105 C has a maximum fuel capacity of 580.0 liters (153.22 U.S. gallons), of which 570.0 liters (150.58 U.S. gallons) are usable. The range is 691 miles (1,112 kilometers.

The original Type Certificate for the Bölkow Bo-105 A was issued 13 October 1970. Since then, the Bo-105 series has been produced in Germany, Canada, Spain, Indonesia and the Philippines. More than 1,500 were built.

Wilfried von Englehart tests the Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA, at Ottobrun, Germany, 16 February 1967. (Eurocopter)
Wilfried von Engelhardt tests the Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA, at Ottobrun, Germany, 16 February 1967. (Airbus Helicopters Deutschland GmbH)
Charles (“Chuck”) Aaron demonstrates the aerobatic capability of the Messerschmitt-Bölkow-Blohm Bo-105 CBS-4, N154EH. (Red Bull)
Baron von Engelhardt’s parents

Wilhelm Friedrich Franz Eugen Baron von Engelhardt was born at Schloss Liebenberg, north of Berlin, Germany, 11 September 1928. He was the son of the Rudolf Robert Baron von Engelhardt and Ingeborg Maria Alexandrine Mathilde Baroness Engelhardt (Gräfin zu Eulenburg), and the grandson of Friedrich-Wend Fürst zu Eulenburg-Hertefeld, Count of Sandels.

Wilhelm von Engelhardt had an early interest in aviation.  His stepfather, Generalmajor Carl-August von Schoenebeck, a World War I ace, commanded the Luftwaffe flight test agency at Flugplatz Rechlin-Lärz, Rechlin, Germany. Von Englehardt was able to meet a number of well known German pilots, some of whom were guests at the family home. At the age of 16, he began flight training in gliders.

With the approach of the Soviet Red Army, von Engelhardt and his family fled to Austria. (General Shoenebeck was held as a prisoner of war until 1948.) He trained in hotel management in Salzburg. Following his release from Allied custody, General Schoenebeck formed Luftfahrt-Technik, a distributor for several aircraft manufacturers, including Hiller Helicopters.

With the assistance of General Schoenebeck, in the early 1950s von Engelhardt went to Paris, France, to train as a helicopter mechanic. He next became a helicopter pilot, then flight instructor, in 1958. He flew the Hiller 12, the Bell 47, and the gas turbine-powered Sud-Ouest Djinn. Von Engelhardt flew the SNCASE SE.3130 Alouette II in Papua New Guinea, 1961–1962, then returned to France where he trained as a test pilot at École du personnel navigant d’essais et de réception (EPNER) at Istres.

Von Engelhardt was recommended as test pilot for the Bölkow-Entwicklungen KG Bo-46, by the helicopter’s rotor system designer, Hans Derschmidt. The Bo-46 was an experimental high-speed helicopter. Von Engelhardt made the first liftoff of the prototype aircraft 14 February 1964.

Bölkow-Entwicklungen Bo-46 V-1, D-9514, with the Derschmidt rotor system. (Johan Visschedijk Collection, No. 6705/1000aircraftphotos.com)

Wilhelm von Engelhardt served as Bölkow’s chief test pilot, from 1962 to 1973. He then became the company’s sales director and director of customer service training.

With the Soviet occupation of eastern Germany, the village where Baron von Engelhardt was born was seized. It later came under the jurisdiction of the German Democratic Republic. Following the reunification of East and West Germany, the government of the Federal Republic of Germany held control of Schloss Liebenberg.

Schloss Liebenberg is now a hotel. (Michelin)

In 1996, without informing the local population, the Federal Office for Special Tasks Related to Unification, government’s privatization agency, placed the entire village, including the castle, the 13th century church, all the homes, farm buildings and stable, for sale. The asking price was so high that it was impossible for the villagers to come up with enough money to buy their home town. There was considerable outcry from the villagers, who said that they felt as if they, too, had been put on sale.

Baron von Engelhardt, who was living in a rented coach house on the estate that his family had owned for more than 300 years, gained international recognition for his attempts to negotiate a reasonable outcome.

With his wife, Evamaria, he edited and published Brücke über den Strom, (“Bridge over the Stream”), the letters of his cousin, Sigwart Botho Philipp August zu Eulenburg, Count of Eulenburg, a musical composer who was killed during World War I.

Wilhelm Friedrich Franz Eugen Baron von Engelhardt died 24 January 2015, at the age of 86 years.

Wilfried Baron von Englehardt 1928-2015)
Wilhelm Friedrich Franz Eugen Baron von Engelhardt (11 September 1928–24 January 2015)

© 2019, Bryan R. Swopes

16 February 1965, 14:37:03 UTC

Pegasus A/SA-9 (AS-103) liftoff, 16 February 1965, 14:37:03 UTC (NASA KSC 65-19630)

16 February 1965: At 9:37:03 a.m., Eastern Standard Time (14:37:03 UTC), Pegasus A (later redesignated Pegasus I), a satellite designed to detect meteoroid impacts in Earth orbit, is launched from Launch Complex 37B at the Cape Kennedy Air Force Station, Cape Kennedy, Florida, aboard a Saturn I Block II launch vehicle. The satellite is enclosed in a boiler plate Apollo Command and Service Module.

The all-up vehicle is designated AS-103. The combined first and second stage launch vehicle is designated SA-9. It consisted of an S-I first stage (S-I-9) and S-IV second stage (S-IV-9). The boilerplate Apollo CSM is identified as BP-16.

The three Pegasus satellites were the only ones to use a Saturn launch vehicle. Pegasus A was the largest satellite launched up to that date, with a mass of 1,451.5 kilograms (3,200 pounds).

This was the eighth flight of a Saturn I rocket, and the fourth for a Saturn IV second stage.

AS-103 lifted off from a 47 foot × 47 foot (14.33 × 14.33 meters) square metal pedestal. At the center of the pedestal was a 32-foot diameter dodecagon-shaped opening for the rocket engines’ exhaust. A twin-sloped flame deflector under the pedestal was coated with a concrete-like heat-resistant material to minimize damage to the deflector.

The trajectory of AS-103. (NASA Press Kit 65-38)

At T+8 seconds, AS-103 began a roll and pitch maneuver, taking it to a flight azimuth of 105°. The roll maneuver ended 15 seconds later. The Saturn I reached Mach 1 at T+54 seconds, and the maximum dynamic pressure (max Q) at T+66. The pitch program was completed at T+138. At T+140.22, the four inboard H-1 engines were cut off (IECO), and the outer engines, 5.34 seconds later (OECO).  At this time, AS-103 had reached an altitude of 55 miles (89 kilometers), and was 44 miles (77 kilometers) downrange. It was traveling at 6,000 miles per hour (9,656 kilometers per hour).

The Saturn I first stage was jettisoned. Four solid fuel retro rockets were to slow the first stage, but one malfunctioned shortly after ignition. The first stage impacted the ocean surface at T+718.95, 961.29 kilometers (597.32 miles) down range. (N. 25.8155, W. 71.3491)

At T+148.12, the command to start the six RL10 engines of the second stage was sent. The two stages had separated by 10.95 meters (35.93 feet) at engine ignition. (the minimum requirement was 3 meters/9.8 feet.) Ten seconds later, the Launch Escape System was jettisoned.

After about 8 minutes, at T+631.659, the S-IV-9 engines were cut off and the vehicle was inserted into orbit 1,200 miles, (1,931 kilometers) downrange, with a velocity of 8,091.1 meters per second (29,128 kilometers per hour/18,099 miles per hour).

At T+813, the Command and Service Module was separated, and at T+863.4, the Pegasus wings began to deploy. This took 39.6 seconds. These panels had an overall span of 96 feet (29.261 meters) and width of 14 feet (4.267 meters). They carried 208 detector panels. Each panel was 3 feet, 4 inches × 1 foot, 8 inches × 1 inch (1.016 x 0.508 x 0.0254 meters).

A 50-second video of this evolution can be seen on YouTube at:

Pegasus I stabilized in a 430.00  × 523.00 kilometer (267.19 × 329.33 miles) elliptical orbit with a period of 94.10 minutes. As residual fuel (approximately 700 pounds) from the S-IV second stage, which remained attached to the satellite, vented, Pegasus began to tumble.

Pegasus I had about eighty times the detecting area than the Explorer I satellite, which had been launched 31 January 1958. By late May 1965, more than 70 meteoroid hits had been detected.

NASA issued a contract to build three Pegasus satellites, two for flight and third as a backup, to the Fairchild Stratos Corporation in February 1963. (Fairchild Hiller Corporation after 1964.) Final assembly took place at the Aircraft-Missiles Division, Hagerstown, Maryland. (In fact, all three were launched.) Pegasus A was transported by aircraft and arrived at Cape Kennedy Air Force Station on 20 December 1964.

“In this photograph, the Pegasus, meteoroid detection satellite is installed in its specially modified Apollo service module atop the S-IV stage (second stage) of a Saturn I vehicle for the SA-9 mission at Cape Kennedy. Personnel in the service structure moved the boilerplate Apollo command module into place to cap the vehicle. The command and service modules, visible here, were jettisoned into orbit to free the Pegasus for wing deployment. The SA-9 was launched on February 16, 1965.”

When stored inside the boiler plate command and service module, the satellite was 17 feet, 4 inches (5.283 meters) long, 7 feet, 0 inches (2.134 meters) wide, and 9.5 inches (24.13 centimeters) deep.

Pegasus I was deactivated 29 August 1968. Its orbit decayed and it reentered the Earth’s atmosphere 17 September 1978. BP-16, the boilerplate Apollo CSM, remained in orbit until 10 July 1985.


AS-103 consisted of a Saturn I Block II first stage, S-I-9; a S-IV second stage, S-IV-9; a boilerplate Apollo Command and Service Module, BP-16; with a Launch Escape System tower. It had a height of approximately 57.3 meters (187.99 feet). It weighed 1,110,941 pounds (503,914 kilograms) at First Motion, including 878,179 pounds (398,335 kilograms) of propellant.

S-I-9 was the last Saturn S-I first stage to be built at NASA’s Marshall Space Flight Center in Huntsville, Alabama. (SA-8, SA-10, and the following Saturn first stage boosters were produced by the Chrysler Corporation Space Division at NASA’s Michoud Assembly Facility in New Orleans, Louisiana.) The Block II variant was modified for use by the United States Air Force to launch it’s proposed X-20 Dyna-Soar manned orbital vehicle. The most visible modification are the very large fins for enhanced stability, along with four smaller stub fins. These fins extended radially 9 feet (2.7 meters) from the thrust structure, and each had a surface area of 121 square feet (11.24 square meters). S-I-9 was barged to the Cape Kennedy Air Force Station, arriving there 30 October 1964.

Saturn I Block II first stage. 1. TV Camera, 2. Movie Camera, 3. Hydrogen Chill-Down Duct, 4. Cable Tunnel, 5. Four Turbine Exhaust Ducts, 6. Four Stub Fins, 7. Eight H-1 Engines, 8. Four Fins, 9. Heat Shield, 10. Firewall, 11. Anti-Slosh Baffles, 12. One 105-inch (2.667 meters) Diameter LOX Tank, 12. Anti-Slosh Baffles Eight 70-inch (1.778 meters) diameter Tanks, 13. Instrument Compartment (typical F-1 & F-2), 14. Four Retro-Rockets. (NASA MSFC-9801761)

S-I-9 was 80.3 feet (20.275 meters) long and 21.4 feet (6.523 meters) in diameter. Eight Redstone 5 feet, 10 inch (1.778 meters) diameter rocket fuel tanks, with four containing the RP-1 fuel, and four filled with liquid oxygen, surrounded a 8 feet, 9 inch (2.667 meter) diameter Jupiter rocket fuel tank containing liquid oxygen. The stage was powered by eight uprated Rocketdyne H-1 engines. The eight engines produced 1,500,000 pounds of thrust (6,672 kilonewtons) at Sea Level.

The Saturn S-IV-9 second stage was built by the Douglas Aircraft Company’s Missile & Space Division, Huntington, Beach, California. It was 41.5 feet (12.65 meters) long and 18.5 feet (5.64 meters) in diameter and had an empty weight of about 14,000 pounds (6,350 kilograms). It carried 100,386 pounds (45,534 kilograms) of propellant. The stage was powered by six Pratt & Whitney RL10A-3 rocket engines. The six engines produced 88,976 pounds of thrust (395.785 kilonewtons). The stage was coated with a special heat resistant paint developed by the Illinois Institute of Technology, Chicago. The S-IV stage was transported by aircraft and arrived at the Cape Kennedy Air Force Station 23 October 1964.

Pegasus Deployment Sequence (NASA)

“Fairchild technicians check out the extended Pegasus meteoroid detection surface. The Pegasus was developed by Fairchild Stratos Corporation, Hagerstown, Maryland, for NASA through the Marshall Space Flight Center. After being placed into orbit around the Earth, the satellite unfolded a series of giant panels to form a pair of wings measuring 96 feet across.” (NASA)

NASA considered the Saturn S-I series to be remarkably successful. Up to this time, new rockets failed at a rate of 50% during two to three dozen tests.

© 2024, Bryan R. Swopes

16 February 1946

The prototype Sikorsky S-51 commercial helicopter, NX19800, in flight between Bridgeport and East Hartford, Connecticut, 1946. (Sikorsky Historical Archive)
The prototype Sikorsky S-51 commercial helicopter, NX92800, in flight between Bridgeport and East Hartford, Connecticut, 1946. (Sikorsky Historical Archive)

16 February 1946: The Sikorsky S-51 prototype, NX92800, made its first flight. The test pilot was Dimitry D. (“Jimmy”) Viner, who later made the first civilian rescue using a helicopter. The S-51 was the first helicopter intended for commercial use, though it was also widely used by military services worldwide. (The prototype was later delivered to Aéronavale, French Naval Aviation.)

Dimitry D. ("Jimmy") Viner with a Sikorsky S-51, the civil version of the R-5. (Sikorsky Historical Archive)
Dimitry D. (“Jimmy”) Viner with a Sikorsky S-51, the civil version of the R-5. (Sikorsky Historical Archive)

The S-51 was a commercial version of the Sikorsky R-5 series military helicopters. It was a four-place, single engine helicopter, operated by one pilot. The cabin was built of aluminum with Plexiglas windows. The fuselage was built of plastic-impregnated plywood, and the tail boom was wood monocoque construction.

The main rotor consisted of three fully-articulated blades built of metal spars and plywood ribs and covered with two layers of fabric. (All metal blades soon became available.) The three bladed semi-articulated tail rotor was built of laminated wood. The main rotor turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) The tail rotor was mounted on the helicopter’s left side in a pusher configuration. It turned clockwise as seen from the helicopter’s left. (The advancing blade is below the axis of rotation.)

Sikorsky S-51 three-view illustration with dimensions. (Sikorsky Historical Archives)

The helicopter’s fuselage was 41 feet, 1¾ inches (12.541 meters). The main rotor had a diameter of 48 feet, 0 inches (14.630 meters) and tail rotor diameter was 8 feet, 5 inches (2.568 meters) giving the helicopter an overall length of 57 feet, ½ inch (17.386 meters). It was 12 feet, 11-3/8 inches (3.947 meters) high. The landing gear tread was 12 feet, 0 inches (3.658 meters).

The S-51 had an empty weight of 4,050 pounds (1,837.05 kilograms) and maximum takeoff weight of 5,500 pounds (2,494.76 kilograms). Fuel capacity was 100 gallons (378.5 liters).

Sikorsky S-51 NC92813, Los Angeles Airways, departs on a commercial flight, Los Angeles, California, 1947. (LAT)
Sikorsky S-51 NC92813, Los Angeles Airways, departs on a commercial flight, Los Angeles, California, 1947. (Los Angeles Times)

The helicopter was powered by a 986.749-cubic-inch-displacement (16.170 liter) air-cooled, supercharged, Pratt & Whitney Wasp Jr. T1B4 (R-985 AN-5) direct-drive,  nine-cylinder radial engine which was placed vertically in the fuselage behind the crew compartment. This engine had a compression ratio of 6:1 and was rated at 450 horsepower at 2,300 r.p.m., Standard Day at Sea Level. The R-985 AN-5 was 48.00 inches (1.219 meters) long, 46.25 inches (1.175 meters) in diameter and weighed 684 pounds (310.3 kilograms) with a magnesium crankcase.

The S-51 had a maximum speed (VNE) of 107 knots (123.1 miles per hour/198.2 kilometers per hour). Range was 275 miles (442.6 kilometers). The service ceiling was 14,800 feet (4,511 meters). The absolute hover ceiling was 3,000 feet (914.4 meters).

Of 220 helicopters in the S-51 series built by Sikorsky, 55 were commercial models. Westland built another 159 helicopters under license.

One of Los Angeles Airways' Sikorsky S-51 helicopters takes off from roof of the the Terminal Annex Post Office, Los Angeles, California, 1 October 1947. (Los Angeles Times Photographic Archive/UCLA Library)
One of Los Angeles Airways’ Sikorsky S-51 helicopters takes off from roof of the the Terminal Annex Post Office, Los Angeles, California, 1 October 1947. (Los Angeles Times Photographic Archive/UCLA Library)
Dimitry D. Viner, circa 1931

Дмитро Дмитрович Вінер (Dimitry Dimitrovich Viner) was born in Kiev, Ukraine, Imperial Russia, 2 October 1908. He was the son of Dimitry Nicholas Weiner and Helen Ivan Sikorsky Weiner, a teacher, and the sister of Igor Ivanovich Sikorsky.

At the age of 15 years, Viner, along with his mother and younger sister, Galina, sailed from Libau, Latvia, aboard the Baltic-American Line passenger steamer S.S. Latvia, arriving at New York City, 23 February 1923.

“Jimmy” Viner quickly went to work for the Sikorsky Aero Engineering Company, founded by his uncle, Igor Sikorsky.

Dimitry Viner became a naturalized United States citizen  on 27 March 1931.

Viner married Miss Irene Regina Burnett. They had a son, Nicholas A. Viner.

On 29 November 1945, Jimmy Viner and Captain Jackson E. Beighle, U.S. Army, flew a Sikorsky YR-5A to rescue two seamen from an oil barge which was breaking up in a storm off of Fairfield, Connecticut. This was the first time that a hoist had been used in an actual rescue at sea.

A Sikorsky R-5 flown by Jimmy Viner with Captain Jack Beighle, lifts a crewman from Texaco Barge No. 397, aground on Penfield Reef, 29 November 1945. (Sikorsky Historical Archive)

In 1947, Viner became the first pilot to log more than 1,000 flight hours in helicopters.

Dimitry Dimitry Viner died at Stratford, Connecticut, 14 June 1998, at the age of 89 years.

© 2019, Bryan R. Swopes

16 February 1932

Martin XB-907 in flight. (U.S. Air Force)

16 February 1932: First flight, Glenn L. Martin Co. Model 123, designated XB-907 by the U. S. Army Air Corps. It was powered by two Wright Cyclone SR-1820-E engines rated at 600 horsepower, each. The engines were covered by Townend rings to reduce drag and improve cooling.

Martin XB-907

The prototype was tested at Wright Field.  The airplane reached a maximum speed of 197 miles per hour (317 kilometers per hour) at 6,000 feet (1,829 meters). Recommendations for modifications were made, and Martin upgraded the prototype to the XB-907A configuration (Martin Model 139), which was then designated XB-10 by the Air Corps, with the serial number 33-139.

Martin XB-907A, right profile. (U.S. Air Force)

Martin increased the XB-907A’s wingspan from 62 feet, 2 inches (18.948 meters) to 70 feet, 7 inches (21.514 meters). The engines were upgraded to Wright R-1820-19s, rated at 675 horsepower. Full NACA cowlings were installed.

The Army then ordered 48 production airplanes.

The XB-907 would be developed into the Martin B-10 bomber.

U.S. Army Air Corps Martin B-10B of the 28th Bombardment Squadron, Philippine Islands 28 November 1939. (U.S. Air force)

© 2019, Bryan R. Swopes