First Successful Automatic Airplane Landing
Carl Crane, George Holloman and Raymond Stout standing beside the Fokker C-14B used to test the first successful instrument landing system.
On August 23, 1937 a Fokker C-14B took off from Wright Field near Dayton, Ohio. The
equipment was turned on and the aircraft headed to Patterson Field, also located nearby,
where it gradually descended and landed by using a quad-radio system consisting of 5 radio
transmitting beacons. The experiment was a low-budget, out-of-pocket affair by Army
Air Corps Captains Carl Crane, Director of the Instrument and Navigation Laboratory;
George Holloman, Assistant Director; and Mr. Raymond Stout, project engineer.
The C-14B was fitted with radio receivers, electrical components and mechanical linkages. The flight proved successful and earned the team the prestigious MacKay Trophy.
A project report written by Crane and his team had the following description of the project, its purpose and benefits:
"For more than a year Air Corps test airplanes have been flown automatically over distances that have indicated the thorough reliability of the devices employed. This was one step in the perfection of automatic landing. The features that are built into the automatic landing system are not only useful for the landing, but are used throughout the entire flight. Test airplanes from Wright Field have been flown automatically from Wright Field as far as Texas and return under automatic control. Several flights have been made to Buffalo, Newark, thence to Langley Field, Va., and return to Wright Field. Obviously the automatic landing involves other factors besides control of direction. These factors are control of altitude, engine control, glide control and further engine control after landing.
In the execution of the automatic landing, using the Air Corps system, it is necessary for the pilot to bring the plane to a definite altitude, determined by the sensitive altimeter, and to place the machine within the range of radio reception of the ground radio facilities. It is, of course, desirable to place the airplane generally in the direction in which it is expected to land, but this is not necessary, as was determined in flight.
Once the master landing switch is closed, the plane proceeds through the following routine:
The selected altitude is automatically maintained and the plane's heading is changed (automatically) so that it flies in the direction of the radio guiding station most remotely located from the landing runway. The altitude control device maintains the proper altitude during the initial approach. The directional relay interlocks the radio compass and the Sperry gyro pilot, and therefore causes the change in the heading of the plane. Adjacent to this relay is the radio compass, the frequency of which is automatically set by the interaction of the marker beacon receptor working in conjunction with the frequency selector. The pilot is informed as to the correctness of automatic settings by observing the frequency selector indicator. Through the automatic and cooperative action of these devices the airplane heads to the compass guiding station farthest from the field. Upon reaching that station the frequency is automatically changed to Station No. 3, where it is again automatically changed to the frequency of Station No. 2, where the frequency is again automatically changed to that of Station No. 1, while at the same time the engine throttle is automatically operated by the throttle engine. The throttle engine is interconnected with the altitude control in such a manner that should the plane reach its minimum altitude prior to reaching radio Station No. 1, the throttle engine will be so actuated as the control the plane and keep it at minimum altitude required for the operation of the automatic landing system.
After passing Station No. 1, the throttle system is so actuated that the plane remains at a selected glide angle and rate of descent until ground contact is made. When ground contact is made, the landing gear switches further actuate the throttle engine, which in turn causes the engine to be idled and the proper brake application made.
At this writing [late 1937] the automatic landing system has been used so that all the landings made to date have been under cross wind conditions of varying intensity and as high as 11 miles per hour. In at least 50 per cent of the landings air conditions have been rough."
The Project Aircraft
Fokker Y1C-14B
The project aircraft, a Fokker Y1C-14B, was a military
version of the Fokker-Atlantic six-seat Fokker F-14 single-engine parasol-wing commercial
transport with a different engine installed. The original Y1C-14s were powered by
the 525 hp Wright R-1750-3 Cyclone radial engine. The Y1C-14B was powered by
the more powerful 750 hp Pratt & Whitney R-1690-5 Hornet radial engine was installed
in place of the original R-1750-3 Cyclone radial.
Fokker Y1C-14A
A Fokker-Atlantic F-14 operated by Western Air Express
