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Aviation History
1961
1961 - 1519.PDF
Stages in the evolution of the F-/04: A, Model 227-0-11; 6, 227-0-6; C, 227-8-/; D, 227-/6-2; £, 227-14-1; F, 227-13-1; G, 227-15-3. All drawings on this page have been prepared to the same scale, emphasizing the variation in size between projects. For dates, see text ribs in the tail unit. Approximately 60 lesser forgings are of the zero-draught close-tolerance variety, which the company estimates has saved approximately 40 per cent of the cost of conventional machined parts. To provide the increased control power required for operations at low altitudes and increased gross weights, modifications were made to the tail unit. The principal change represents a refinement of the enlarged vertical tail originally developed to counteract the increased side area of the tandem-seat nose of the F-104B. Lockheed ex- tended the leading edge of the fin forwards, incorporated irrever- sible hydraulic power to drive the rudder and eliminated the separate yaw-damper tab previously fitted. At the same time, the hydraulic boost system for the horizontal tail was appreciably increased in power. Modifications were made to improve the performance of the wing. Chief among these is an alteration to the control system governing the trailing-edge flaps, to enable the latter to be employed as manoeuvring flaps. Lockheed claim that their use "results in as much as 33 per cent reduction in airplane turn radius at an altitude of 5,000ft." These flaps are fully blown, and for take-off and landing are supplemented by the full-span leading-edge flap. The latter is machined from a slab of 7075-T6, and the leading-edge radius is so sharp (0.016in) that felt protective guards are frequently employed during maintenance operations. The ailerons are hung on 90-ton-steel piano hinges and driven by hydraulic manifolds serving ten parallel actuating rods. Logical modifications to the landing gear included fully powered brakes with an anti-skid system energized by sensing units in the axle of each wheel. At the same time, the diameter of the braking parachute was increased from 16ft to 18ft, and Lockheed briefly investigated the practicability of fitting an arrester hook. It was decided to add electro-thermal de-icing elements to the engine intakes, and the choice fell upon the British Spraymat, produced under Napier licence by Pacific Airmotive Corporation. To increase range during purely offensive operations, provision was made to replace the six-barrel M61 gun and ammunition bay by an aluminium fuel tank with a capacity of 120 US gal. What the F-104G Can Carry Modifications of this nature were all largely decreed by the decision to turn the aircraft into an attack vehicle with the ability to carry a wide range of external stores. Most important of these are the "Special Weapons"—the euphemistic term for nuclear bombs— many types of which can be hung from Station 3 on the aircraft centreline. Ten feet away, the wing-tip shoe can carry a Sidewinder air-to-air missile or a tank with a capacity of 170 US gal (see photo- graph, page 622). Stations 2 and 4, beneath the wings, can each carry a 195 US gal tank, an air-to-surface missile (the F-104 has yet to be seen with such a weapon, but the Bullpup and possibly a modified Nord AS.30 come to mind as possible loads'), and a great variety of other stores up to a unit weight of 1,0001b. A similar range of stores, as well as a pair of Sidewinders or a 225 US-gal tank, can be hung on Station 3 already mentioned. In parallel with these extensive airframe modifications Lockheedsketched a very complete system for internal and external arma- ment. The only internal armament of the earlier models was theGeneral Electric M61 "Vulcan" six-barrel gun, with a single-belt feed, installed in the lower port side of the forward fuselage. Thiswas retained, but modified in detail to increase rate of fire to the theoretical 6,000 rds/min: and electric drive was standardized. The question of all-weather radar, fire control, weapon-delivery systems, navigation and instrumentation was far more complex.Lockheed were fortunate in that a major nation, with a potential requirement for a very large number of aircraft, had since mid-1957been giving the Lockheed proposals far more than a cursory examin- ation. This nation was the Federal Republic of Germany. During 1958 German engineers co-operated with Lockheed indeveloping a model appropriately called the F-104G. If anything, this was to be an even more advanced aeroplane than the F-104-7already planned. It was soon clear that its operational equipment and maximum external load would raise the overload weight to atleast 20,0001b, and it is a remarkable fact that the resulting aircraft has the same wing and powerplant as the earlier versions. After an evaluation of "nearly two dozen of the world's topfighter aircraft," the Federal Government in Bonn announced their choice of the F-104G as their future standard tactical aircraft inFebruary 1959. Lockheed have described how the painstaking and protracted evaluation of the large team from the Luftwaffe and HerrStrauss's Defence Ministry gradually narrowed the list of US designs down to two aircraft. The other machine was clearly theGrumman G-98 Super Tiger, powered by the same engine as the F-104. It had the advantage of being a fait accompli, whereas theF-104G was then almost two years distant. But Lockheed claim to have eliminated their rival by a series of competitive performancetrials, using an existing F-104C. Still in the race were one or two European aircraft—in particular,the Mirage HI. In retrospect, there are strong grounds for feeling that this aircraft would have met the requirements of the Luftwaffefully as well as the F-104, but it succumbed to Lockheed's brilliant salesmanship. At that time neither aircraft existed as a developedweapon, but Lockheed were more convincing in describing the equipment which they were going to fit. It is probably fair to sug-gest that something also depended upon the image created by the respective companies: Lockheed presented a bold, confident andunited front; Dassault were a much smaller team, with practically no experience of making presentations of such a character. More-over, the French company's cause can hardly have been assisted by reluctance on Dassault's part to turn their sleek intercepterinto a pylon-festooned attack aircraft. Long before the deal was clinched, Lockheed had evolved acomprehensive specification, and it is appropriate to outline the operational equipment specified for the F-104G before going onto analyse its remarkable success. Many details remain classified, but the basic principles have already been outlined by Lockheed. It is in its electronic features that the F-104G differs principallyfrom the versions of the F-104 ordered by the US Air Force. For the USAF the F-104 is an air-superiority weapon, whereas forEuropean military requirements it needs to perform as an all- weather intercepter, fighter/bomber or reconnaissance aircraft. One of the most important new electronic systems is the multi-purpose NASARR F-15A radar, by NAA Autonetics Division. Consisting of a radar set and a fire-control computer, the equipmentoperates in two basic modes—air-to-ground for bombing and navigation, and air-to-air for target interception—and is capableof providing data-link information read-out. For air-to-ground operation it provides ranging information for bombing computationin visual bombing modes, ground mapping for all-weather bombing, contour mapping for navigation and terrain avoidance. In air-to-air use it provides increased power for radar search, acquisition and automatic tracking of air targets to achieve the capability for:lead-collision attack for automatic release of rockets; lead-pursuit attacks using the M61 gun, with information supplied to director-type gunsight; and pursuit attack with Sidewinder guided weapons. Another important "black-box" is the air-data computer, which (Continued on page 626. after double-page drawing) Final stages in the evolution of the design: H, 227-20-1; ], 242-19-1; K, 242-23-1; L, 246-/-/, M, 242-27-1; N, a design which is virtually the XFI04
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