Ryan FR-1 fireball
Ryan FR-1 Fireball Bureau Number 39657 was delivered to the U.S. Navy in March 1945. 39657 was the 11th production Fireball and was one of only 14 FR-1’s to be delivered with double slotted flaps. The Fireballs were constructed with a composite power plant , that combined a Wright Cyclone R-1830-72 of 1350 hp. with a General Electric I-16 (J-31) jet engine of 1600 lb. thrust. The idea being that the Fireball would operate With the R-1820 engine with the jet engine being used in the combat zone to boost the FR-1’s top speed in its anticipated role as a Kamikaze chaser.
Upon delivery of 39657, it was immediately assigned to Ames Research Center at N.A.S. Moffet Field California along with 5 other Fireballs that were undergoing Flying qualities, Stability, and Control and Performance Evaluations.
These tests were conducted between Feb. 17, 1945 and June 1, 1947 in order to correct ongoing stability problems that the FR-1 Fireball fleet were experiencing. Testing involved variation on Engine tilt angles, Control force characteristics, Wing dihedral, and Aileron shape. In a collaborative effort between Ryan Aircraft and the N.A.C.A., testing was conducted in the 40’ by 80’ wind tunnel at Ames Research Center located at Mt. View, California.
Variable Stability Aircraft Testing
Testing of the FR-1 Fireball led N.A.C.A. engineer Bill Kaufman to develop the concept of Variable Stability Aircraft Testing, a concept that is still being used today. The idea being that the basic flight characteristics of an aircraft could be altered by a stability augmentation so that a wide range of static and dynamic characteristics could be safely simulated and evaluated in flight
The Variable Stability system altered the effective dihedral by deflecting the aircraft’s ailerons in response to side-slip. The cockpit linkage was adjusted so the pilot’s control stick would not move in response to the aileron deflections commanded by the Variable Stability system yet it allowed the pilot to control the axis conventionally.
Later modifications to the Variability Stability system allowed it to command rudder deflection in response to roll rate, side-slip angle and yaw rate while roll rate and side-slip were into the existing aileron deflection system.
By the time these tests were completed, the FR-1 Fireball fleet were being phased out of service with the U.S. Navy due to the early onset of airframe fatigue upon inspection of the aircraft in service. 39657 soon found itself being donated to the Palo Alto High School in Palo Alto, California as an instructional airframe. Later in 1967, 39657 was obtained by Mr. Edward Maloney for his The Air Museum from Palo Alto High School and is currently on display at the Planes of Fame Air Museum in Chino, California. The aircraft is currently on display in the U.S.S. Enterprise hangar.
