F-18 Readies For RAAF Service

However, it can be argued that the F1 made its debut a decade too late, being little more than a supersonic (and vastly improved) Hunter. If the RAAF had actually gone ahead and bought the F1, the service would have been far better equipped since 1975, but it would not have been able to buy an advanced technology fighter for the mid-1980s. In fairness to certain of this writer’s friends who Were pushing the F1 idea in the late 1960s, it must be added that in those days we all thought of a 10-year life to anew fighter; and that 1985 would see a Mirage-replacement-replacement entering service. Few were able to foresee that skyrocketing costs would transform fighter development from steady progress to a series of well-separated major steps. In the new environment, those who come late to a fighter generation (as Germany did with the F-4F) risk being stuck with an old aircraft for a very long time.

In the early 1970s, a RAAF evaluation team made a detailed examination of the Mirage F1, the F-15, the Saab Viggen and the Northrop Cobra, but it was decided that the life-of-type extension work could keep the the Mirage 1110 operating for several more years, hence the decision could be delayed until other options were available. With a new generation in the Department of Air, a formal Request for Proposals was circulated in 1976, with 11 responses, which received initial evaluation in March 1977. This resulted in a shortlist of theMDGF-15 and F/A-18, the Northrop F-18L, the Mirage 2000, the GD F-16, and the Panavia Tornado. By the end of 1979, the list had been further reduced to the F-16 and the F/A-18.

While the people in the Russell offices had been sorting out their ideas on a new fighter, the combat aircraft business had been changing. Experience in Vietnam had shown that earlier USAF thinking on fighter requirements had been too closely linked to a nuclear war, that dedicated strike and intercept aircraft lacked the necessary operational flexibility and (above all) the traditional capability to meet the enemy one-on-one and destroy him at a cost-effective rate. Responding with characteristic energy, America poured money into a new generation of fighter powerplants and into new aircraft concepts that would allow the Phantom-replacement fighters to outclass anything that the Russians could put into the air.

The engines that America produced were the P & W F100 and the GE F404, the latter a more innovative concept with a very low bypass ratio, producing a proportionally higher thrust at transonic speeds and relatively low afterburning Specific Fuel Consumption (SFC). The F100 first found application in the F-15, which flew in July 1972. It is perhaps fair to say that the F100 had more than its share of teething troubles and that it was just as well the F-15 had two engines.

Despite these problems, the USAF recognised that it had in the F-15 the basis for the world’s finest all-weather air superiority fighter. However, in view of the fact that it had been a relatively conventional design, and since new ideas were coming along, the service decided to sponsor a Lightweight Fighter (LWF) prototype programme, which would quickly and cheaply evaluate new concepts, mainly in the area of aerodynamics. The result was a flyoff in 1974 between the GDYF-16 and the Northrop YF-17, during the course of which the USAF suddenly decided to transform the LWF technology demonstration programme into a contest for an air combat fighter (ACF) to complement the F-15. In January 1975 the YF-16 was selected. Whatever Northrop Friday say about the decision, it Was clear that the YF-16 was closer to a production aircraft, and that it offered engine commonality with the F-15.

On the other hand the YF-17 was superior in terms of engine technology and the use of a large leading edge extension (LEX) to permit operation up to very high angles of attack. Its twin-engine configuration and larger size also Make it more attractive to the US Navy as the basis for an A-7 replacement and a fighter complement for the F-14. However, the development of naval aircraft is a very specialised field, in which Northrop had no previous experience, so the task was passed to MDC, with Northrop receiving as a consolation prize the role of principal airframe subcontractor. The resulting. F/A-18 had its maiden flight on 10 November 1978, powered by GE F404 engines, with bypass ratio increased slightly from that of the YF101s in the YF-17. The original US Navy plan was for 11 development aircraft and 800 production F/A-18s, but from FY80 the latter figure has been increased to 1366. Ttie Navy plans to equip 24 attack and 12 fighter squadrons with the aircraft, and to buy 12 fighter and several attack squadrons for the USMC, the latter number depending on the ultimate force mix of F/A-18s and AV-8Bs.

Why the Hornet?

On 10 April 1980 the Canadian government announced the intention to buy 138 CF-18s (including 24 two-seaters) to replace its CF-101s in fulfilling its NORAD (North American Air Defense) commitments, and its CF-5s and CF-104s assigned to NATO. This was to be a procurement programme costing over $US 2 billion in then-year dollars, assuming 8% annual inflation. In the course of negotiations, the US DoD had agreed to reduce R&D charges by $US 70 million, and that the R&D levy ($US 877,690 per aircraft) would be waived on the planned 20 attrition aircraft. Canada received its first Hornets in October 1982, these aircraft being allocated to No 410 Squadron at Cold Lake, Alberta.

It is now standard practice in the more civilised parts of the Free World for the choice of a new military aircraft to be explained to the electorate. In the case of Canada, the ground was laid by a statement from the Minister of national Defence in November 1978. In this he made it clear that the CAF’s numerical requirement for 1 30-150 aircraft was critical, and that the government was disappointed that procurement of sufficient F-14s, F-15s or Tornados could not be accommodated within the set budget of $2. 34 billion (August 1977 dollars). This left Northrop CF-18L, the GD-CF-16 and the MDC CF-18. The CF-18L was eliminated because of the risk of buying a sophisticated aircraft that was not in service elsewhere, and because the delivery schedule was likely to be behind that required. The CF-16 was assessed as having an acceptable capability and appeared (in 1978) to be the only aircraft that could provide the numbers required.

The CF-18 was marginal in terms of numbers procurable, but it was more attractive, in being a somewhat larger, twin-engined aircraft. It had more advanced all-weather capabilities than the CF-16, and had a good potential for growth. The decision was therefore taken to negotiate draft contracts on both the CF-16 and CF-18. The final decision in favour of the latter was spelled out by Brig-Gen P. D. Manson, who had led the new fighter aircraft (NFA) team. In an article in the Canadian Defence Quarterly, he stated that the CF-18 had been selected largely because of its excellence as a multi-role aircraft, able to fulfil a broad range of air-air and air-surface roles in Europe and North America. Manson also emphasised the importance attached to the aircraft’s growth potential and pointed out that the degradation of range with increasing warlord would not be so pronounced as with the CF-16. However, he noted that the CF-18’s low-level radius of action was not as good as might have been desired, and that its maximum speed of approximately Mach 1. 80 could limit its effectiveness in identifying very high speed intruders. The fact that the F/A-18 is a twin-engined aircraft was regarded as an attractive feature, though this was not as crucial as implied in some press reports.

The second largest of the F/A-18 export orders was that for Spain, announced on 23 July 1982, for 84 aircraft. The search for a Future Attack and Air Combat Aircraft (FACA)had begun in 1978. The aircraft was to operate primarily as a ground attack aircraft, but it was also to function as an air superiority fighter. The three principal demands were that it should have full all. -weather day/night capability, that it should be able to operate either as a fighter or ground attack aircraft, and that there should be satisfactory offsets. The contract was worth approximately $US 3 billion, and it covered 72 aircraft with options on 12 more.

As stated earlier, by late 1979 Australia’s own list of fighter contenders had been reduced to the F/A-18 and F-16. On the previous shortlist, the Northrop F-18L had been eliminated as a ‘paper aeroplane’, while the Mirage 2000 had been judged to be at a disadvantage in warlord-radius terms, and to require two specialised radars to be developed for the air-air and air-surface roles. The view of the F-16 was that it was attractive financially, and (given the navigation and targeting pods then in development) could meet RAAF requirements. Since it was running well ahead of the F/A018, it was also a comparatively low-risk option. On the other hand, it lacked a medium-range all-weather air-air missile (Sparrow or AMRAAM), and the F100 engine was still experiencing serious problems. There was also some concern that developments already in hand would eliminate the equipment space required for further growth,. and that the air conditioning system would not be able to cope.

The comparison of the two aircraft was complicated by problems that were still arising in the US. The F-16 suffered a series of accidents that revived the old single-vs-twin argument. On the other hand, the F/A-18 was found to have an inadequate roll rate at high speed and low altitude, due to structural distortion. In addition, there were various fatigue failures on the test rig, and one of the series was lost just after the _1980 Farnborough show, following failure of an F404 LP turbine disc. Finally, the F/A-18 was selected as being ‘better suited to our needs,’ although the F-16 would have been up to seven per cent less expensive.

Defence Minister Sir James Killen made the announcement to the House of Representatives on 20 October 1981, citing a programme cost of $A 2. 430 billion in August 1981 terms. Procurement was to consist of 75 aircraft, including 18 two-seaters, the first two aircraft being delivered from the St Louis production line. In a subsequent statement, Air Cdre Hans Roser, the director-general of the Tactical Fighter Project, said that the aircraft had met or exceeded requirements in 17 out of the 20 areas assessed in the operational testing. Its self-defence capability was rated extremely high. In the early days of the programme, there was concern that a reduction in the planned procurement by the US Navy would lead to a significant increase in unit price to the RAAF, but satisfactory assurances appear to have been given that this will not happen.

In explaining the choice of the F/A-18, the Minister had emphasised that Australia has to allow for the possibility of fighting alone. It followed that the new fighter had to be unusually flexible. The aircraft would also have to be able to function over large areas without the close control that is taken for granted in Europe. The size of the country furthermore dictated an aircraft with an excellent range and endurance. Because conflict in the north might well mean operating from bare bases with long air resupply links and the minimum of support facilities, reliability and maintainability were at a premium. Peacetime attrition and growth potential were also important factors. It was in the light of these considerations that the F/A-18 was judged the more suitable of the two finalists. In particular, it had been designed from the outset as a multi-role aircraft with excellent repair and maintenance characteristics, and considerable growth potential. Its twin engines were felt to offer a clear prospect of fewer losses through its life.

What Makes It Different?

Although MDC has undoubtedly done a magnificent job in transforming the YF-17 into the production F/A-18, the fundamental While the F-18 does not have the long legs of the F-15, its typical combat radius is far in excess of that of the Mirage III. This aircraft is carrying three external 1250 L (300 gal) drop tanks, a Laser Detector Tracker and a FLIR pod mounted on what would normally be the Sparrow AAM stations, four Mk 84 1000 lb bombs and twoAIM-9M Sidewinder AAMs in addition to its gun armament. In this configuration, MDC claims the hornet to have a typical combat radius of around 1000 km. qualities of the Hornet owe a great deal to the original Northrop design. One of the most important qualities of a fighter in the air superiority role is freedom from departures and spins. Some aircraft (such as the F-16) achieve this by means of an automatic flight control system that limits manoeuvres in order to avoid conditions in which the aircraft would depart from controlled flight. In the case of the F/A-18, this is achieved by good airframe design, using a massive LEX to produce powerful vortices over the wings, maintaining a remarkable degree of attached flow on the wings to far higher angles of attack (AOA) than the average squadron pilot would ever wish to use. The vortices also appear to have the effect of increasing directional stability at high. An additional factor in the aircraft’s freedom from departures is the location of the twin vertical tails between the wing and the tailplane, where they experience the minimum of interference from the horizontal surfaces. The F/A-18 has been tested to an AOA of 90 degrees and a sideslip angle of over 40 degrees.

Turning performance benefits significantly from the use of automatic leading- and trailing-edge wing flaps. The F/A-18 is claimed to be the first fighter equipped with a digital quadruplex control-by-wire system. However, mechanical backup is provided on the horizontal tail surfaces, which can give both pitch and roll control in an emergency.

Another important factor in air combat is freedom from engine handling restrictions, and in this respect the 7165 kg General Electric F404-GE-400 turbofans are outstanding. The engines will go from idle to maximum thrust in four seconds, throttle movement is completely unrestricted, and there are no AOA limitations. The F404 is also notably smoke-free, which combines with the aircraft’s relatively small size to minimise visual detection range. Because of the aircraft’s high thrust/weight ratio and the small bypass ratio (0. 34) of its engines, the F/A-18 is quite a lively performer even without afterburner, hence it enjoys a significant advantage in regard to combat persistence. It is also noteworthy that the F404 has 7700 fewer parts than the earlier J79, and weighs approximately 50% less.

The ‘Star Wars’ cockpit of the the F/A-18 owes a great deal to MDC experience with the F-15, featuring a head-up display (HUD) and three CRT multi-mode head-down displays, providing radar and FUR pictures, armament status information, checklists etc. The influence of the F-15 is also to be seen in the HOTAS (hands-on throttle-and-stick) control system, enabling the pilot to fight without moving his hands from the essential controls. Aside from the normal weapon firing/release, airbrake and radio controls, the pilot also has buttons on the control column for weapon selection and on the throttles for radar and FLIR control and flare/chaff dispensing. The aircraft has a voice warning system, relating to fuel state and altitude.

The F /A-18 also differs from other fighters in having a very high percentage of advanced composite materials: approximately 9% of the structure by weight, and 40% of the surface area.

The radar is a Hughes APG-65, a multi-mode pulse-Doppler equipment operating in both low/medium and high PRFs (pulse repetition frequencies), and providing look-down, shoot-down capability. In the air-air role it has three basic modes of operation. The HUD mode scans the area of sky corresponding to the head-up display. In the vertical acquisition mode, the radar searches over a very narrow width, and acquires the first target within a specific range. The boresight acquisition mode allows the pilot to point the aircraft at the desired target and automatically acquire it. In addition, a raid assessment mode gives increased resolution between closely spaced targets. The gun director mode uses pulse-to-pulse frequency agility to reduce target scintillation, giving very accurate tracking at short ranges.

Maximum possible acquisition range is provided by a velocity search mode using a high PRF against nose-aspect targets, although this provides only bearing and velocity information. A range-while-search mode interleaves high and medium PRFs to detect all-aspect targets. A track-while-scan feature maintains 10 target track files, giving with AMRAAM a simultaneous engagement capability against multiple targets. If the APG-65 lives up to Hughes’ claim to be the most versatile tactical radar in the world today, then it presumably has a facility (or growth potential)for noncooperative target recognition (NCTR), although very little has ever been made public on this subject.

In the air-surface role, the radar provides long-range mapping with Doppler beam sharpening facilities, terrain avoidance, precision velocity update for the INS, tracking of fixed and moving targets, air-surface ranging, and sea surface search. In this role, the Sparrow/AMRAAM grooves are used to accommodate a FLIR pod and one containing a laser detector/tracker (LDT).

The F/A-18 has an internal M61 Gatling gun and nine external hardpoints, i. e. three on the fuselage, two Sidewinder stations on the wingtips, and four underwing pylons. Maximum external load is 7300 kg.

The aircraft has an empty weight of 10,850 kg, and a take-off weight of approximately 16,350 kg in the air defence role, with two AIM-9s, two AIM-7s, and full internal fuel of 4925 kg. On internal fuel it has an intercept radius of up to 750 km, but this can be increased to 1300 km with drop tanks. In a typical strike mission with four Mk 83 (455 kg)bombs, three 1195 litre drop tanks and two AIM-9s for self-defence, it weighs approximately 21,350 kg and has a radius of more than 1000 km. Maximum take-off weight is 23,600 kg, and ferry range is 3700 km.

Although lacking the glamour of the ‘wild blue yonder’ performance figures, the aircraft’s R & M characteristics are no less important. Looking at 1983 data for production-standard aircraft, the F/A-18 exhibited an MFHBF (mean flight hours between failures)of 2. 20 hr, compared to 0. 7 hr for the A-7E andF-4J/S, and 0. 6 hr for the A-6E and F-14A. It also demonstrated an MMH/FH (maintenance man-hours per flight hour)of 26. 0, compared to 46. 1 for the A-7E, 50. 9 for the A-6E, 51. 6 for theF-4J/S, and 60. 2 for the F-14A. The F/A-18 will thus clearly provide a major improvement over its predecessors in terms of manpower demands and availability

 Australia’s Hornet

The RAAF F/A-18 will differ from the USN/USMC version minor respects. The only modification of any real significance is the addition of HF radio, which is specifically required to deal with communications over northern Australia. In addition, the RAAF aircraft will have an undercarriage-down tone, AFDAS (Australian Fatigue Data Analysis System), a more capable video/voice recorder, a landing light, a Martin-Baker ejection seat harness, ILS/VOR, and wiring provisions for the later fitment of a reconnaissance pod. It will also be cleared to allow the continued use of standard RAAF practice bombs.

Following the delivery of the first two aircraft by C-5A from St Louis earlier this year, the first Australian-assembled aircraft will come off the GAF Avalon line next April, withF404 engines assembled and tested by CAC, undercarriages manufactured by HdH, and APG-65 radars assembled and sted by Phillips in Sydney. In all, 25 different Australian companies are involved in the F/A-18 programme. Production is expected to peak at a rate of three each two months.

The first RAAF unit to receive the F/A-18 will be No 2 OCU at Williamtown, with any necessary Mirage conversion work then being performed by the operational squadrons. Hornet conversion training (as distinct from instructor training) is scheduled to begin in mid-1985. It is anticipated that the OCU will be fully equipped by mid-1986, and the three operational squadrons, each with 16 aircraft, by early 1989. With 13 aircraft as an initial reserve, all four units should be maintained at full strength for most of their operationallivesof20-25 years.

In comparison with the Mirage 1110, the F/A-18 will provide much greater radius of action, and its new technology pulse-Doppler radar will give not only far greater acquisition ranges but also a genuine look-down, shoot-down capability against low-flying intruders. The latest variants of the AIM-9 and AIM-7 (the latter to be superseded by AMRAAM) will produce a major advance in air-air armament.

In the air-surface role, the shortcomings of the Mirage 1110 are well-known. The F/A-18 will bring quantum improvements in warlord, radius of action, navigation accuracy and weapon delivery. The radar and HUD will allow safe low-altitude navigation at night and in bad weather, and its high resolution will enable point targets to be found. The FLIR pod will provide night-time pictures of the outside world, and the LDT equipment will be developed to act as a stabilised laser designator to guide ‘smart’ weapons against ground targets.

To summarise, the F/A-18 is a major advance on the Mirage 1110 in terms of operational flexibility and the latest in equipment and armament technologies. Its introduction will represent the start of a new era in combat capability for the RAAF.