5 July 1917: First flight, the first of two Fokker Versuch 5 (V.5) triplane prototypes, designated F.1, serial number 102/17.
The Fokker F.I was a prototype single-engine, single-seat triplane fighter, designed and built by Fokker Flugzeugwerke GmbH, Schwerin, Germany. After very slight changes, the production version would be designated Fokker Dr.I. The fuselage was constructed of steel tubing braced with wire and covered with fabric. The wings used plywood ribs and a boxed plywood spar.
The two V.5s were improved variants of the V.4 prototype. The wingspan was increased and interplane struts were added.
The F.I was 5.770 meters (18 feet, 11.2 inches) long. The upper wing had a span of 7.190 meters (23 feet, 7.1 inches); the middle wing, 6.225 meters (20 feet, 5 inches); and the lower wing, 5.725 meters (18 feet, 9.4 inches). All three wings had a chord of 1.000 meters (3 feet, 3.4 inches). The airplane had an overall height of 2.950 meters (9 feet, 8.1 inches). Its empty weight was 405 kilograms (893 pounds), and the gross weight was 587 kilograms (1,294 pounds).
Fokker F.1 102/17
Originally built with a Motorenfabrik Oberursel Ur.II nine-cylinder rotary engine rated at 110 horsepower (a license-built copy of the French Le Rhône 9J engine). The Le Rhône 9J, produced by Société des Moteurs Le Rhône, was an air-cooled, normally aspirated, 15.074 liter (919.85 cubic inches) nine-cylinder rotary engine, capable of producing 113 horsepower at 1,200 r.p.m., and a maximum 135 horsepower at 1,350 r.p.m. As the engine rotated, it turned a two-bladed Axial Proppellerwerk AG fixed-pitch, laminated wood propeller with a diameter of 2.660 meters (8 feet, 8.7 inches). The Le Rhône 9J was 850 millimeters (2 feet, 9.47 inches) long and 970 millimeters (3 feet, 2.19 inches) in diameter. It weighed 137 kilograms (302 pounds).
Fokker F.1 102/17
The Fokker F.I had a maximum speed of 185 kilometers per hour (115 miles per hour) at Sea Level and 166 kilometers per hour (103 miles per hour) at 4,000 meters (13,123 feet ). The service ceiling was 7,000 meters (22,966 feet). It carried fuel for approximately 1½ hours of flight.
The F.I was armed with two fixed 8mm Spandau LMG 08/15 machine guns, synchronized to fire forward through the propeller arc. The fighter carried 550 rounds of ammunition per gun.
Fokker F.1 102/17. The curved leading edge of the horizontal stabilizer is seen.The second protototype, F.1 103/17, was flown by Leutnant Werner Voss. It was ordered on 14 July 1917 and accepted by the German Air Force on 16 August. It was sent to Jagdstafell 10 on 21 August. Shot down 23 September 1917
Fokker F.1 102/17 was shot down by a Sopwith Camel, 15 September 1917 near Wervik, Belgium. The pilot, Oberleutnant Kurt Wolff, was killed.
Lockheed Vega s/n 1, now marked NC2788 (SDASM)The first Lockheed Vega 1 NX913 taking off at Rogers Airport, 4 July 1927. (Water and Power Associates)
4 July 1927: The first Lockheed Aircraft Company Vega 1, NX913, made its maiden flight with test pilot Edward Antoine (Eddie) Bellande at Rogers Airport, Los Angeles, California. The airport was at the present location of Wilshire Boulevard and Fairfax Avenue, west of downtown Los Angeles.
Bellande was a U.S. Marine Corps flight instructor, and a stunt pilot, test pilot and airline pilot. By the time he had retired in 1943, he was second in seniority among the pilots at Trans World Airways (TWA).
Rogers Airport, 1922. (Los Angeles Public Library)Edward Antoine (“Eddie”) Bellande sits with famed motion picture hero, Rin Tin Tin, ca. 1925. (E. A. Bellande Collection)
The Lockheed Vega was a single-engine, high-wing monoplane designed by John Knudsen (“Jack”) Northrop and Gerrard Vultee. Both men would later have their own aircraft companies.
The Vega was very much a state-of-the-art aircraft for its time. It used a streamlined monocoque fuselage made of strips of vertical-grain spruce pressed into concrete molds and bonded together with cassein glue. These were then attached to former rings. The wing and tail surfaces were fully cantilevered, requiring no bracing wires or struts to support them. They were built of spruce spars and ribs, covered with 3/32-inch (2.4 millimeters) spruce plywood.
Concrete molds used to form the fuselage halves for the Lockheed Vega. (SDASM)Components of the first Lockheed Vega 1 before assembly at the Lockheed Aircraft Company, Hollywood, California, 1927. (SFO Museum)Fuselage construction at the Lockheed factory. (Lockheed Martin/SDASM)
The Lockheed Vega 1 was flown by a single pilot in an open cockpit and could carry up to four passengers in the enclosed cabin. It was 27.5 feet (8.38 meters) long with a wingspan of 41.0 feet (12.50 meters) and height of 8 feet, 6 inches (2.59 meters). The total wing area (including ailerons) was 275 square feet (25.55 square meters). The wing had no dihedral. The leading edges were swept slightly aft, and the trailing edges swept forward. The Vega 1 had an empty weight of 1,650.0 pounds (748.4 kilograms) and a gross weight of 3,200 pounds (1,452 kilograms).
The Vega 1 engine was an air-cooled, normally-aspirated 787.26-cubic-inch-displacement (12.901 liter) air-cooled Wright Aeronautical Corporation Model J-5C Whirlwind nine-cylinder radial engine. This was a direct-drive engine with a compression ratio of 5.1:1. The J-5C was rated at 200 horsepower at 1,800 r.p.m., and 220 horsepower at 2,000 r.p.m. It was 2 feet, 10 inches (0.864 meters) long, 3 feet, 9 inches (1.143 meters) in diameter, and weighed 508 pounds (230.4 kilograms).
The Vega had a cruising speed of 110 miles per hour (177 kilometers per hour) with the engine turning 1,500 r.p.m., and a top speed of 135 miles per hour (217 kilometers per hour)—very fast for its time. The airplane had a rate of climb of 925 feet per minute (4.7 meters per second) at Sea Level, decreasing to 405 feet per minute (2.1 meters per second) at 10,000 feet (3,048 meters). Its service ceiling was 15,900 feet (4,846 meters), and the absolute ceiling was 17,800 feet (5,425 meters). The airplane had a fuel capacity of 100 gallons (379 liters), giving it a range of 1,000 miles (1,609 kilometers) at cruise speed.
The first Vega 1, NX913, Golden Eagle, nears completion at the Lockheed Aircraft Company, Hollywood, California, 1927. (SFO Museum)
Twenty-eight Vega 1 airplanes were built by Lockheed Aircraft Company at the factory on Sycamore Street, Hollywood, California, before production of the improved Lockheed Vega 5 began in 1928 and the company moved to its new location at Burbank, California.
The techniques used to build the Vega were very influential in aircraft design. It also began Lockheed’s tradition of naming its airplanes after stars and other astronomical objects.
Lockheed Vega 1, NX913, left profile. There is no registration number painted on the rudder in this photograph. (San Diego Air and Space Museum Archives)Lockheed Vega 1 NX913 was sold to George Randolph Hearst to enter in the Dole Derby California-to-Hawaii Air Race, and named “Golden Eagle.” (JMF Haase Collection, SDASM Archives)Lockheed Vega s/n 1, NX913. (SDASM)Lockheed Vega 1, marked NC2788. (SDASM)The first Lockheed Vega, now marked NC2788, at Oakland, California, August 1927. (Left to right) Jack Frost, Eddie Bellande, Jack Northrop, Allan Loughead, Ken Jay. (Vintage Air)
Golden Eagle, with its pilot, Jack Frost, and navigator Gordon Scott, was lost while crossing the Pacific Ocean in the disastrous Dole Derby California-to-Hawaii Air Race, 16 August 1927.
Martin XPB2M-1 Mars, Bu. No. 1520. (Hans Groenhoff Photographic Collection, Smithsonian Institution National Air and Space Museum NASM-HGC-1059)
3 July 1942: Chief Test Pilot William Kenneth Ebel, Ph.D., Vice President of Engineering for the Glenn L. Martin Company, took the Martin Model 170, s/n 877, for its first flight, lifting off from the waters of Chesapeake Bay. Dr. Ebel’s co-pilot was Ellis Dent Shannon, who would later become the chief test pilot for Convair.
Designated XPB2M-1 Mars, Bureau of Aeronautics serial number (“Bu. No.”) 1520, by the United States Navy, the flying boat was a prototype for a long-range patrol bomber. The first rivets had been driven for the airplane’s keel 22 August 1940, and the Mars was launched 8 November 1941. During a test in December 1941, the prototype had been damaged when a runaway propeller tore away from the No. 3 engine.
The Martin Mars prototype was launched 8 November 1941. (Charles M. Daniels Collection, San Diego Air & Space Museum Archives, Catalog #: 15_001975)
The U.S. Navy’s experiences early in World War II led it to adopt the Consolidated B-24 Liberator as its long range bomber (PB4Y-1 and PB4Y-2 Privateer). The XPB2M-1 was converted to a transport configuration, the XPB2M-1R, in 1943. The Navy ordered twenty transport versions, designated JRM-1. By the end of the war, only six had been built and the remaining order was cancelled.
Martin Model 170 Mars (XPB2M-1 Bu. No. 1520) at the Glenn L. Martin Co. ramp, near Baltimore, Maryland, 13 May 1942 (United States Navy, National Naval Aviation Museum, NMNA 1985.0481.003)
The Martin XPB2M-1 was a large, four-engine flying boat, operated by a crew of 11 persons. It was 118 feet, 9 inches (36.195 meters) long with a wing span of 200 feet, 0 inches (60.96 meters), and height of 37 feet, 4 inches (11.379 meters). The hull had a maximum width (“beam”) of 13 feet, 6 inches (4.115 meters). The total wing area was 3,683 square feet (342.2 square meters). The flying boat had an empty weight 75,573 pounds (34,279 kilograms), and gross weight of 140,000 pounds (63,503 kilograms).
The XPB2M-1 prototype was powered by four air-cooled, supercharged, 3,347.66-cubic-inch-displacement Wright R-3350-4 engines with a compression ratio of 6.85:1. Burning 100-octane aviation gasoline, these engines had a normal power rating of 1,700 horsepower at 2,300 r.p.m., and 2,000 horsepower at 2,400 r.p.m., at Sea Level for Takeoff. They drove three-bladed 16 foot, 6 inch (5.029 meters) diameter Curtiss Electric constant-speed propellers through a 16:7 gear reduction. The R3350-4 was 5 feet, 11.5 inches (1.816 meters) long, 4 feet, 7.12 inches (1.400 meters) in diameter, and weighed 2,450 pounds (1,111 kilograms).
The prototype Mars had a maximum speed of 221 miles per hour (356 kilometers per hour) at 4,500 feet (1,372 meters). It took 27.1 minutes to climb to 10,000 feet (,048 meters), and its service ceiling was 14,600 feet (4,450 meters). The flying boat’s fuel capacity was 10,410 gallons (39,406 liters), with 664 gallons (2,514 liters) of lubricating oil. This gave it a maximum range of 4,945 statute miles (7,958 kilometers)at 135 miles per hour (217 kilometers per hour). The maximum endurance was 37.1 hours at 131 miles per hour (211 kilometers per hour).
In the patrol bomber configuration, the XPB2M-1 could carry bombs or torpedoes. It was armed with machine guns for defense.
The XPB2M-1 was assigned to VR-8 at NAS Patuxent River, 27 Nov 1943, and later transferred to VR-2 at NAS Alameda. It was withdrawn from service in March 1945, and beached at Alameda. In April 1945 it was returned to Martin Co. for JRM-1 crew training. The prototype served as a maintenance trainer until 1949. It was then broken up.
The airplane once flew from PAX in the United States to Natal, Brazil, a distance of 4,375 miles (7,041 kilometers), while carrying a payload of 13,000 pounds (5,897 kilograms).
JRM: 0 -lift over drag coefficient 0.0233, max lift over drag 16.4
Martin Mars taxi test (Charles M. Daniels Collection, San Diego Air & Space Museum Archives, Catalog #: 15_001976)Martin Model 170 in flight. (Charles M. Daniels Collection, San Diego Air & Space Museum Archives, Catalog #: 15_001977)
Not So Graceful
It was not so graceful as it was towed from the Martin plant into the misty bay by small auxiliary craft.
Through the mists from following craft it looked like as large gray whale.
It was moved slowly by the power boats down Dark Head Creek from the plant and into the channel of the bay, 15 miles north of the mouth of the Patapsco River.
At the controls was William K. Ebel, chief test pilot and vice-president in charge of engineering at the Martin Company.
Maneuvered Slowly
He maneuvered the Mars slowly. When the towing boats cast off and while fireboats stood by, he started each engine separately.
It was at this point last December, during a water test, that the No. 3 propeller tore away.
No such mishap occurred yesterday. As the motors warmed, Ebel took the flying boat in half circles, first right, then left.
Then he “gunned” her and the Mars sailed through the water down the bay to meet boats carrying naval officials, executives of the Martin Company and Washington officials.
Twenty-Man Crew
With the twenty-man crew headed by Pilot Ebel, Co-Pilot Ellis E. Shannon, Capt. Harold Gray of Pan American Airways and Flight Engineer Benjamin Zelubowski, the ship warmed up for thirty minutes.
Brig. Gen. James H. Doolittle sat with Glenn L. Martin in the observer’s boat.
Out of the sky came a not-so-small navy amphibian plane. It paced the huge flying boat down the Chesapeake and hung over its right wing as the four largest propellers in the world lifted the ship from the water.
Together, the two planes disappeared toward the southwest. Within thirty minutes the Mars was back. It “bumped” easily four times and sat down just as easily in the water.
Martin Jubilant
Within a few minutes it was off again. This time it met the water evenly as it landed, then was immediately taken off again.
Its manufacturer, Glenn L. Martin, was jubilant over the flying boat’s maiden performance.
—The Sun, Baltimore, Maryland, Vol. 211, No. 42, Saturday, 4 July 1942, Page 18, Columns 3 and 4, and continued on Page 4, Column 6
Martin XPB2M-1 Mars with a 1941 Piper J3C-65 Cub, NC40743. (Hans Groenhoff Photographic Collection, Smithsonian Institution National Air and Space Museum NASM-HGC-1073)
William Kenneth Ebel was born at Orangeville, Illinois, 2 January 1899. He was teh son of Willam Henry Ebel, a farmer, and Nora Agnes Rubendall Ebel.
One 1 October 1918, Ebel was enlisted as a private in the Student Army Training Corps (SATC). He was trained at Heidelberg College, Tiffin, Ohio. With the end of the War, Private Ebel was discharged 20 Dec 1918.
Ebel continued his education at Heidelberg, graduating with a Bachelor of Arts (B.A.) degree in 1921, and in 1923, he completed a Bachelor of Science in Mechanical Engineering (B.S.M.E.) at the Case School of Applied Science, Cleveland, Ohio.
Also in 1921, Ken Ebel joined the 104th Observation Squadron, Maryland National Guard, based at Baltimore. He was assigned as an aviation cadet from 11 September 1923 to 3 June 1924. He was trained as a pilot at the National Guard Primary Flying School.
On 12 January 1925, William K. Ebel was commissioned as a second lieutenant, Air Service, Officers Reserve Corps. He was promoted to first lieutenant, Air Corps, 21 December 1926. He continued to serve with the Maryland National Guard
Also in 1926, Lieutenant Ebel began his career as an engineer and test pilot for the Glenn L. Martin Company.
Effective 15 February 1929, Ebel’s reserve officer’s commission was converted to first lieutenant, Air Corps.
On 21 October 1929, William Kenneth Ebel married Miss Florence E. Sherck at Seneca, Ohio. The would have two children.
Ebel was promoted to captain, Air Corps, 5 January 1935.
The first Martin Marauder, B-26-MA 40-1361, takes off for the first time at Middle River, Maryland, 25 November 1940. (U.S. Air Force)
On 25 November 19840, Ken Abel made the first flight of the Martin B-26 Marauder twin-engine medium bomber.
Ebel earned a doctorate degree in engineering (Ph.D.) from Case.
After the War, Ebel left Martin. In 1948, he became the director of the airplane division Curtiss Wright Corporation at Columbus, Ohio. In 1950 he was appointed vice president of engineering for Canadair Ltd., a Canadian aircraft manufacturer owned by the General Dynamics Corporation. After serving as a consultant for General Dynamics in Washington, D.C., Ken Ebel retired.
Mrs. Ebel died in 1968. He later married Ms. Helene H. Topping
Walter Kenneth Ebel died at the Greater Baltimore Medical Center, Baltimnore, 12 July 1972.
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, 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.
The prototype Douglas DC-1, X223Y, takes off from Clover Field, Santa Monica, California, 1 July 1933. (Airport Journals)
1 July 1933: 12:36 p.m., the Douglas DC-1 took off from Clover Field, Santa Monica, California, on its first flight. In the cockpit were Carl Anson Cover and Fred Herman.
Douglas DC1 X223Y. (SDA&SM)
The duration of the flight was just twelve12 minutes. during the flight both engines lost power several times. It was later determined that the engines’ carburetors had been installed backwards. This caused their floats to close when the airplane was in a climb.
Douglas DC-1 X223Y (San Diego Air & Space Museum, Michael Blaine Collection, Catalog #: Blaine_00263
The Douglas DC-1 was a prototype commercial transport, built by the Douglas Aircraft Company, Santa Monica, California. It was a twin-engine, all-metal, low-wing monoplane with conventional landing gear. It had a flight crew of two pilots, and provisions for 12 passengers.
Douglas DC-1 NC223Y. (American Aviation Historical Society, via Smithsonian Magazine)
The new airplane had been requested by Transcontinental and Western Air, Inc. It would be required to take off on a single engine from Winslow, Arizona—at 4,941 feet (1,506 meters) above Sea Level, the highest airfield in the T.W.A. route—and to climb to an altitude of 10,000 feet (3,048 meters), again on only one engine. It was required to carry more passengers than the Boeing Model 247, and to have a landing speed of 55 miles per hour (89 kilometers per hour).
The Douglas DC-1, X223Y, in flight. (Larry Westin)
The DC-1 was 60 feet, 0 inches (11.288 meters) long, with a wing span of 85 feet, 0 inches (25.908 meters), and height of 16 feet, 0 inches (4.877 meters). Its empty weight was 11,780 pounds (5,343 kilograms), and gross weight, 17,500 pounds (7,938 kilograms).
The DC-1 was powered by two supercharged, air-cooled, Wright Cyclone SGR-1820-F3 nine-cylinder radial engines, These engines had a compression ratio of 6.4:1 and required 87-octane gasoline. They were rated at 700 horsepower at 1,950 r.p.m. They turned three-bladed variable-pitch propellers throug a 16:11 gear reduction. The -F3 was 3 feet, 11-3/16 inches (1.199 meters) long, 4 feet, 5¾ inches (1.365 meters) in diameter, and weighed 1,047 pounds (475 kilograms).
Douglas DC-1 X223Y at Grand Central Air Terminal, Glendale, California.
The DC-1 had a cruise speed of 190 miles per hour (306 kilometers per hour) and maximum speed of 210 miles per hour (338 kilometers per hour). Its range was 1,000 miles (1,609 kilometers), and the service ceiling was 23,000 feet (7,010 meters).
Only one DC-1 was built. It was rolled out of its hangar 22 June 1933. Registered X223Y, it made its first flight, 1 July 1933, at Clover Field, Santa Monica, California, with test pilots Carl Cover and Fred Herman in the cockpit.
NC223Y was retired from passenger service in 1936. T.W.A. loaned it to the U.S. government for high altitude research. In May 1938 NC223Y was sold to The Right Honourable Vicount Forbes at Croydon, 27 May 1938, and registered G-AFIF, 25 June 1938. It was re-sold to France, in September 1938. The DC-1 was again sold, this time to Spanish Republican government, and operated by Lineas Aéreas Postales Espanolas, also known as LAPE. The airplane made a forced landing at Malaga, Spain, in December 1940. It was damaged beyond repair.
Wreck of the Douglas DC-1, Malaga, Spain. (Weird Wings)A model of the Douglas DC-1 being tested in the Guggenheim Aeronautics Laboratory (GALCIT) 10-foot wind tunnel at the California Institute of Technology (CalTech) in Pasadena, California. (California Institute of Technology)
