F/A-18 Hornet: The Now and Future Backbone
Originally conceived as a low-cost replacement for two aging naval aircraft (the F-4 Phantom and A-7E Corsair), the F/A-18 Hornet fighter-bomber was designed to fulfill a number of widely different roles. It functions as both the Navy's primary light-strike bomber and as a fighter for the Navy and Marines. Though some think the Hornet does neither job very well, others consider it the finest multi-role aircraft in the world. Some will tell you that the F/A-18 is a short-legged burden on naval aviation, while others will make a case that it is the backbone for all of naval aviation. I would tell you it is all of these things, and many more. The drawback with any multi-role combat aircraft is that it tries to do too much for too many different people. On the other hand, when such a complex beast works, it works out quite well indeed. Read on and I'll explain.
The origins of the Hornet program date back to the mid-1970's, when the Navy was beginning to suffer "sticker shock" from the costs of buying new aircraft for its carrier force. The double-digit inflation of the early 1970's was driving the price of new combat aircraft up at a dangerous rate, bringing about a reassessment of the kinds and numbers of aircraft the U.S. military could afford. After a start was made on the modernization of the F-14, A-6, and S-3, the Navy looked to the problem of replacing the existing force of A-7 light-attack bombers. Since every CVW had two squadrons each of the A-7's (with a dozen aircraft per squadron), this represented a huge aircraft buy. At the same time, the Navy and Marines had to replace about a dozen squadrons of elderly F-4 Phantom fighters, which operated from carriers and bases. From these twin needs came what was known as the VFAX (Navy Fighter/Attack, Experimental) requirement. The hope was that a single aircraft might be designed to fulfill both the fighter and light-strike roles, and thus save money by reducing the number of airframes. About the same time, the USAF was evaluating a pair of "lightweight" fighter designs, and was preparing to procure one of them. Since the USAF was going to use this aircraft as a multi-role fighter-bomber, the Congress and Department of Defense directed that the Navy and Marines should use a version of the same aircraft. That is where the troubles began.
The two competing lightweight fighter designs, the General Dynamics (GD, now part of Lockheed Martin) YF-16 and the Northrop (also now part of Lockheed Martin) YF-17, had a "fly-off" competition at Edwards AFB in California. When it was over, the YF-16 was declared the winner, and has proved to be an outstanding combat aircraft. The USAF and our allies have bought thousands of the little fighters, and continue to do so to this day. Unfortunately, many of the qualities that made the USAF love the F-16 were unacceptable in a carrier-based aircraft. For example, the Navy prefers twin-engined aircraft for their redundancy and ability to accept battle damage. The F-16 has only a single engine, and is too lightly built to carry some of the equipment needed for carrier operations. Since the Navy had been directed to base the VFAX aircraft on the contenders from the USAF lightweight-fighter competition, it chose to run a "paper" competition that would allow it to evaluate and choose the airplane it would buy.
Meanwhile, both GD and Northrop decided that since neither had recent experience building carrier aircraft, they would look for a partnership with an aircraft company that did. Thus GD in Fort Worth teamed up with its crosstown neighbor Vought, while Northrop adopted McDonnell Douglas (MDC) in St. Louis as its partner. At the end of the evaluation process, the Navy chose a derivative of the twin-engined, twin-tailed YF-17, which it judged was better suited to the rigors of duty aboard aircraft carriers. This award to MDC/Northrop provoked a loud protest from the losing Vought/ GD team, which had thought the original DoD/Congressional direction was an ironclad guarantee that they would win. Though it took an inspired campaign of political pressure and technical documentation by the Navy to preserve the decision, the MDC/Northrop team held on to their win. But there is more to the story.
Winning a contract is one thing. Building the aircraft specified is another thing entirely; especially when it is the most advanced of its type ever built. The Navy and Marine Corps were asking a great deal more from the new aircraft than the USAF was of the F-16, and that complicated matters greatly. For instance, the new bird, now designated the F/A-18 Hornet (the F/A stood for Fighter/Attack), would have to carry a great deal more equipment than the USAF bird. This included a multi-mode radar capable of providing guidance for the large AIM-7 Sparrow AAMs and FLIR targeting pods it was to be equipped with. The Hornet would also have to lug around a lot of extra weight in the form of beefed-up structure (representing about 4,000 lb/1,818.2 kg, approximately 20 % of the Hornet's total weight), to allow it to operate on and off carriers. These requirements proved to be far beyond the modest abilities of the YF-17. The Navy was in fact asking not simply for a Navy version of the original Northrop design, but for a brand-new aircraft. Simply scaling up the YF-17 was not going to do.
To further compound the difficulties presented by this design, there was no true prototype of the F/A-18. The first Hornets to fly were preproduction aircraft, which went directly into operational testing at NAS Patuxent River, Maryland. This meant that any normal problems that might have shown up (and been eliminated) in a prototype were now found in the preproduction birds. This proved to be a costly mistake. In fact, some problems (such as structural cracks) did not show up until the Hornet was actually into squadron service with the fleet. There were also troubles with the aerodynamics around the "cobra hood" and leading-edge extensions, which had to be modified fairly late in the development process. Luckily, the ability of the F/A-18's new digital fly-by-wire (FBW-the first ever on a carrier-capable aircraft) flight-control system to be reprogrammed made the fix relatively easy. The worst problem, though, was the scarcity of internal fuel tankage.
One of the most important measures of a combat aircraft's range is expressed by a number called the fuel fraction; that is, the weight of internal fuel expressed as a percentage of an aircraft's takeoff weight. Normally, combat aircraft designers like to build aircraft with a fuel fraction of between.30 and.35. This gives enough gas to fly a decent distance, drop bombs or dogfight, and then return to the base or boat with a minimum of refueling from airborne tankers. In the design of the Hornet, the fuel fraction was woefully low. The origins of this problem dated from the original YF-17 design. That aircraft had been a technology demonstrator that did not require the kind of fuel load a combat aircraft would normally carry. Thus, the Northrop designers had not installed large internal fuselage tanks. In the process of "scaling up" the YF-17 into the Hornet, the MDC designers had failed to take this into account. For some reason that still defies explanation, the F/A-18 was given the same fuel fraction as the original YF-17-around.23. As a result, the Hornet would never be able to fly all of the missions that had been specified in the original VFAX requirement. For example, when operating in a bombing mode, the F/A-18 cannot possibly fly the same weapons loads as far as the A-7E Corsair, which it replaced.
The Hornet's "short legs" came to light just as the Navy was about to make the production decision for the aircraft. It took more than a little hand-wringing and more than a few briefings to Navy, Marine, and Congressional leaders to make the case to put the F/A-18 into production. The NAVAIR rationalization was that since the aircraft had shown such good performance in so many other areas of flight test, the really-long-range-strike-mission requirement could be compromised. For example, the new APG-65 multi-mode radar was quickly hailed as one of the best in the world, and the weapons system integration made the Hornet an ordnance-delivery dream. Besides, the test and fleet pilots loved flying the new bird. They could see its potential, and were willing to accept a few shortcomings to get the Hornet into the fleet. So the decision to buy the first production batch of Hornets was made, and the first deliveries to VFA-125 at NAS Lemore, California, began in 1980. With this part of the story told, let's take a closer look at the F/A-18.