A STUDY IN EGRESS EVOLUTION:

Case in point: The Lockheed F-104 Starfighter

 

 

[Not only is the Lockheed F-104 Starfighter one of the most fascinating modern aeronautical designs ever to come off a drafting table, the aircrew ejection (egress system) development that accompanied it is a story in itself.]

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            The Lockheed F-104 Starfighter originated in the perceived need for a high performance dedicated air superiority fighter by US Air Force pilots engaged in Korean War air combat. Although the Air Force itself did not have such a requirement in the very early 50s, Lockheed’s Kelly Johnson personally visited the Korean Theatre early in the war and soon concluded that superior speed and altitude were the two most critical needs of the American airmen who had found themselves facing the surprisingly capable Russian designed MiG-15 fighter, itself a product of Russia’s excellent utilization of German World War Two advances in aeronautical science.

            Returning to the United States, Johnson’s design team began studies for such a ‘super-fighter’ that drew heavily on the Douglas Aircraft’s experimental research X-3 design. Incorporating the super-thin wing design of that aircraft, along with other aspects of its developmental data produced in its 1952 flight testing. After nearly 14 different combinations of features had been explored, Lockheed finally produced their Model 83, which later became known as the F-104 Starfighter. When the first flight of the XF-104 prototype took place, in March of 1954, the design had been formalized in a form very close to what the very last production Starfighter would look like. The short, stubby wings (each only 7.5 feet long) were optimized for low-drag high speed flight over a broad Mach environment (as was the high horizontal stabiliser), although the relatively high wing-loading (about 95 pounds per foot) yielded poor maneuvering capabilities. Nevertheless, the concept evolved and was advanced as a point interceptor to counter relatively poorly maneuvering Russian bomber intrusion.

            Due to the aircraft’s anticipated supersonic performance, clearly some sort of effective aircrew ejection system would have to be a mandatory feature of the F-104, despite the fact that US Air Force pilots in Korea insisted that they neither wanted nor needed ‘ejection seats’ in their aircraft! Again, the Douglas X-3 experimental research aircraft appeared to provide a feasible approach to the anticipated need with its downward firing pilot ejection seat.

            In the early 1950s, the technology of egress systems for high speed aircraft was still in its infancy. Much of the knowledge that had led to the very first USAF production ejection seat (that used in the Republic F-84 Thunderjet) had come directly from captured German WWII aeronautical research and the capabilities of the existing ballistic catapults were such that great concerns existed over the ability of these catapults to loft a pilot safely up and over the high tail of a supersonic aircraft like the Starfighter. Since it was also felt that safe ejection was most important at high altitudes and speeds, the basic Douglas X-3 downward firing ejection system was used as a design inspiration for the F-104 seat. Since the Douglas X-3 seat had been reasonably well flight tested and shown to be safe to use, given sufficient altitude, it seemed to make sense to install a similar system in the new F-104 point interceptor.

            Thus it was that Lockheed subcontracted the Stanley Aircraft Company (the firm that had developed the X-3’s downward firing seat for Douglas Aircraft) to engineer the Starfighter’s egress system. The Stanley “B-seat”, closely based upon the X-3 system, was the very first ejection seat used in the new Starfighter. This seat was fitted to the prototypes and the first 26 production F-104A aircraft. It was a system that featured retention for the pilot’s legs similar to the Stanley seat used in the X-3, since arm and leg flail due to wind-blast effects had been shown in ejection seat tests to be serious concerns. The Stanley “B-seat” required the pilot to manually move his feet back against the seat’s foot recesses to activate clamps that would hold the feet to the seat before ejection could take place. This maneuver, plus a pull on the seat pan’s triangular grab-ring located between the knees, would initiate the sequence of events that would fire ballistic thrusters to rotate thigh guards into position, tighten restraints, and lock the pilot’s inertia reel harness. The seat would then begin to move down the seat rails and mechanically unlock the belly hatch under the seat, which would then be swept away by the windblast. When this sequence of actions had been completed, an M-3 initiator would ignite the catapult’s explosive charge to fire the seat clear of the aircraft in a downward trajectory. A gravity release back-up system was also incorporated, in the event the ballistic charge in the catapult failed. Separation from the seat was through manual release of the pilot’s belts and restraints, falling clear of the seat, after which an automatic system released his personal parachute.

            The next seat used in the Starfighter was called the Stanley “C-seat” and it was installed in the 15 subsequent F-104A production aircraft. The C-seat added a set of spurs that were worn on the pilot’s shoes, to which were attached cables that would automatically retract the pilot’s feet when the grab-ring was pulled, as part of the ejection sequence. It also featured an improved automatic seat belt and restraint release system, as well as an anaeroid parachute deployment system that would activate automatically when a certain altitude was reached.

            A further refinement of the Stanley “C-seat” resulted in the Stanley “C-1 seat”, which closely resembled the previous two seats in general appearance, but which featured a number of further advanced safety systems. Whereas many contemporary ejection systems required a separate action to release the aircraft’s canopy prior to initiating ejection, on the C-1 system the entire sequence of ejection events was initiated with a single pull on the triangular grab-handle. Upon pulling up on the ring (known to some pilots as the “chicken-ring”), the thigh guards would rotate into position, the feet would be retracted and held securely to the seat, the pilots seat belts and shoulder restraints would be tightened and locked, the belly escape hatch would be ejected and the seat fired down and out. Once clear of the aircraft, an automatic system would cut the foot spur cables, release the seat restraints, and push the pilot out of the seat, where his barometrically activated chute would deploy at the right altitude. There were reportedly less than 100 of the C-1 seats manufactured and installed in early F-104A production aircraft.

            Unfortunately, by the time the first three years of service had been completed by production F-104A models it had become dreadfully clear that the original downward firing ejection seat concept was seriously flawed. The early GE J-79-3A engine used in the Starfighter was prone to engine failures, flame-outs, and malfunctions, many of them occurring on take-off and at very low altitudes and speeds. In the event of such a loss of power the emergency protocol required that a Starfighter pilot roll the aircraft to the side (ideally becoming inverted) so that the downward firing seat would then shoot “up” out of the belly. As might be predicted, reality almost always varied from the ideal escape scenario in the manual, and a number of Air Force pilots were lost in these abortive escape attempts. It became clear that an upward firing seat system was needed, since the majority of in-flight emergencies were occurring at low speed and low altitude, rather than at higher altitudes and faster speeds.

            Finally, Lockheed admitted the need and a hasty program was initiated to remove the dangerous downward firing seats and replace them with a new Lockheed upward firing C-2 seat (in about 1962). The C-2 seat, although it closely resembled the earlier seats in general appearance, incorporated a new and improved ballistic charge catapult that finally allowed the Starfighter’s high tail assembly to be cleared upon ejection at high speeds. The seat’s headrest box was strengthened so as to allow it to blow through a canopy that wouldn’t jettison properly and certain other refinements were incorporated into the C-2 seat’s design. A half-circular “D-ring” was substituted for the original triangular pull handle and a rotary actuator system actively separated the pilot and seat after clearing the aircraft. While the new C-2 system was far better than any of the downward firing predecessor designs, it was still not a ZERO/ZERO seat (that is, a seat capable of saving an ejecting pilot at zero altitude and zero  speed). The C-2 seat nominally required a forward speed of at least 80 knots and an altitude of about 50 feet to insure a safe recovery.

            Due to changing US Air Force requirements and the fact that the Starfighter had a relatively small internal fuel load, the F-104 did not see much use in US air defense. It was used only briefly and in limited numbers as an air defense interceptor, until later, more capable interceptors came into use (notably the Convair F-106 Delta Dart). In the late 60s, however, Lockheed managed to sell the F-104 aircraft to NATO allies, most particularly to Germany. This led to the production of a large number of improved Starfighters under license overseas, but the requirement Germany imposed on the F-104 was for a ground attack aircraft—a role it had never been intended to be used in. Due to this fact, the terrible European weather, insufficient aircraft maintenance, and pilot training issues (German crews trained at sunny Luke AFB, where the weather is always perfect for flying, and then returned to face the typical perpetually marginal European weather which was seldom clear or ideal for flight operations), Germany lost a large number of its F-104G (German) Starfighters. Most accidents and emergencies occurred at very low altitude and close to the ground, where the Lockheed C-2 seat was unsuited to safe recovery. Even the replacement of the C-2’s catapult with an improved, higher-performance rocket catapult system did not satisfy the German Luftwaffe and it ultimately selected The Martin Baker Aircraft Company of the UK to devise a suitable, safe, and true ZERO/ZERO seat system for their Starfighters.

            Martin Baker took their Mark 5 seat (already in use), added a rocket catapult system to it, and reconfigured the seat to fit the small confines of the F-104’s cockpit. After some initial problems that required moving the seat further aft (about 6 inches), so as to clear the instrument panel sun-shield, the new Martin Baker GQ-7A ejection seat was found to perform excellently in all emergency egress situations and this seat (with some additional modifications) remained the last ejection seat used in the Lockheed F-104 Starfighter through the retirement of the last NATO F-104S models by Italy in 2004.

            A final refinement of the basic Lockheed C-2 upward firing ejection seat system was the S/R-2 seat. This seat used a ‘Stabilisation/Retardation’ (S/R) system that deployed a fast-acting drogue chute to keep the seat from tumbling out of control upon ejection and also helped slow the seat/man package sufficiently to allow safe main chute deployment at higher speeds where a chute might be damaged by more severe aerodynamic forces. The S/R-2 system allowed a faster, safer egress from a disabled aircraft at either high or low altitude and also featured an improved high-altitude life support (oxygen) capability. A ballistic slug deployment system on the seat’s chute pack would quickly drag the pilot chute out into the slipstream at the man-seat separation moment , providing the correct altitude had been reached (this function was  barometrically controlled). This chute system (similar to the BA-24 used on F-105 and F-106 aircraft) was also retroactively fitted to some C-2 seats. The SR-1 seat, used in the Lockheed SR-71 Blackbird Mach III recon aircraft was very similar to the S/R-2 seat system, but was optimized for the SR-71’s exceptionally high and fast operational profile.

            The seat you see here today is a specimen of the early Lockheed C-2 ejection seat, as used in both late model USAF F-104s and early German F-104G models. It used a Bendix contracted seat-survival kit (it could also be used with the USAF P/N 140000-44 seat survival kit, very similar to the Bendix kit) that carried an enhanced emergency bailout oxygen system for escape at high altitude. The earliest and original F-104 Starfighter operations were carried out at high altitude, requiring use of a partial pressure suit that the Bendix seat survival kit interfaced with. After the Starfighter evolved from its high altitude mission to a lower altitude profile (ground attack, etc.), the seat kit’s emergency bailout oxygen system was frequently removed and a pressure suit was not needed. Of particular interest is the oval ring mounted on the left side of the seat’s headrest; this was a back-up foot-spur cable cutter deployment initiator that allowed the pilot to free his feet from the seat in an abortive ejection or emergency. Note the two massive swing-arms located on either side of the seat that have “No Lift” on them. These were thigh protector guards that swung forward on ejection; when they moved forward they pulled a protective web net out on both sides of the seat to also protect the pilot’s arms from wind-blast. Finally, note the unique “spurs” that are found in the footrest recesses. These are attached to the seat via cables to automatically retract the pilot’s feet upon ejection. During regular flight the cables would draw forth freely so that the aircraft could be piloted with only very slight tension on the cables, so as to allow full use of rudder controls in normal operation. These “spurs” were the status symbol of a Starfighter pilot and were worn on the flight boots whenever an F-104 pilot was on alert and ready to scramble.

            The Lockheed C-2 seat on view was manufactured in 1964 and weighs about 80 pounds; it was considered a relatively light design for its day, compared to some of the far heavier 1950s and 60s seat designs (such as the Weber and Stanley seats used in the Boeing B-52 “BUFF”). Fully loaded with seat survival kit and contents, the seat could weigh close to just over 175 pounds installed in an F-104 aircraft.