Saturday, August 10, 2013

Agile fighters - just a thought

I recently watched some video footage of the Su-35 at this year's Paris Air Show; at the start of the year  I also had the distinct pleasure of watching an F-22 Raptor perform its flying display at the Australian International Air Show at Avalon.

In both cases the pilots showed off the low-speed handling characteristics of their aircraft brilliantly, but their displays, much as I enjoyed them, left me with a nagging thought. If you're close enough to your enemy that your platform superiority gives you some sort of advantage in a dog flight (which tends to degenerate into a low-speed combat), than you're too close: you're within range of an infra red guided missile such as a Sidewinder or Asraam which have a high off-boresight cueing capability and are extremely difficult to out-run.

If you're going slowly enough to perform a backwards somersault, or rear back through 90 degrees-plus in a high-alpha 'Cobra' manoeuvre to get your nose on the target, you're a sitting target for a gun or missile shot.

But why would you take the risk anyway? Why not take a shot from long range with an infra red or radar-guided missile? Oh, I forgot - if you're up against a stealthy F-22 or F-35, it may not work. You HAVE to get in close, if you can. Tricky.

When will people get it into their heads that air battles are not simply a sequence of single combats fought at visual range between pilots who are trying to get into each others' "Six O'Clock"?

Saturday, April 13, 2013

75 years on - lessons (and some comfort?) for the Joint Strike Fighter from the Spitfire program

A new fighter aircraft is designed. It embodies a new engine, new construction techniques and new armament. The prototype shows great promise and an order is placed for a significant number of aircraft before production gets under way. But development is slow, and mass production of the aircraft encounters one frustrating delay after another. Its critics grow in number and there is talk of cancellation of the project.

Am I talking about the F-35 Lightning II Joint Strike Fighter? No, I’m talking about that most iconic of combat aircraft the Vickers Supermarine Spitfire, the first production example of which made its maiden flight 75 years ago, on 14 May 1938, in the hands of test pilot Jeffrey Quill.

 That flight took place over two years after the prototype made its maiden flight in the hands of Vickers’ chief test pilot Mutt Summers, on 6 March 1936. A production order for 320 Spitfires was placed with Supermarine just a week after a service test pilot, Flight Lieutenant Humphrey Edwardes-Jones, flew the prototype for the first time on 26 May 1936.

While two years might not seem a long time today, in those days it was an unconscionable delay – and quite avoidable. The result of the mounting delays to the Spitfire program was very nearly the cancellation of the project; right up to early 1940, just months before the Battle of Britain, the Spitfire was seen within the British Air Ministry as an ‘interim’ solution pending development of a more suitable fighter to take on the German Luftwaffe’s Messerschmitt Bf109.

Indeed, so disenchanted with the Spitfire was British officialdom, and so concerned at British industry’s lack of capacity to build fighters in the numbers required, that in March 1940 the British government placed an order with North American Aviation to design and build 320 single-seat fighters of a new design, to be armed with four .303in machine guns and powered by the Allison V-1710 engine. The first of these flew in October 1940 and deliveries began in January 1941, by which time this new aeroplane had been christened the Mustang. But that’s another story.

In 1939 the official view, conditioned by extreme disappointment over the difficulties of putting the aircraft into production, was that production of the Spitfire would eventually be phased out and Supermarine’s factories turned over to production of the twin-engined Westland Whirlwind or Bristol Beaufighter. But when the energetic Lord Beaverbrook was appointed Minister for Aircraft Production in May 1940 he immediately saw that the coming air battle would be fought, and must be won, by the RAF’s Spitfires and Hawker Hurricanes so he made production of these aircraft an absolute priority. 

What was the problem with the Spitfire? There were four, and they all compounded each other.

The first was that although Supermarine was best-known for building the series of Rolls-Royce powered high-speed floatplanes, the S4 through to the S6B, which resulted in Great Britain winning permanent ownership of the prestigious Schneider Trophy, this wasn’t its stock in trade. What it did most was build relatively small quantities of amphibious bi-planes. Supermarine was, in modern terms, little more than a ‘smart’ cottage industry, turning out barely a couple of dozen hand-built aluminium, wood and fabric float planes each year from a factory at Woolston, on the River Itchen, near Southampton.

Notwithstanding the pure genius of its chief designer, RJ Mitchell (and his under-sung aerodynamicist, the Canadian Beverley Shenstone), Supermarine was simply not capable of building a high-speed all-metal fighter in the quantities demanded by the RAF. Its inherent lack of capacity was compounded by the shambolic nature of the Supermarine project office. For all Mitchell’s talent, he and the company’s management were unable to get a grip on the practicalities of producing aircraft in large numbers. Indeed, Supermarine’s parent company, Vickers, sent no less a figure than Dr Barnes Wallis (of Wellington bomber and ‘Dambuster’ bouncing bomb fame) to Supermarine’s plant in order to lick it into shape. Mitchell objected violently and Wallis was posted back to Vickers’ Weybridge factory; Supermarine continued on its traditional path, straight towards disaster.

The second major problem facing the Spitfire program was that, like its exact contemporary the Bf109, the Spitfire was a radical departure in the design and construction of high speed fighters. For a start, it was all-metal. This was the only way to achieve Mitchell’s design aim of a thin, strong wing and slim fuselage capable of sustaining very high speeds. Secondly, it was designed for speed, not ease of production: there was barely a straight line on the aircraft; rather, like a woman’s body, a series of elegant curves blended gracefully into one another to produce a single glorious whole. Seen from any angle it was arresting and beautiful. And it was an absolute pig to manufacture.

Initially, Supermarine planned to build most of the fuselage at Woolston and carry out final assembly at its nearby Eastleigh aerodrome. Manufacture of the wings and other components such as the entire tail section would be outsourced to local manufacturers.

The problems with this scheme were that, first, none of the sub-contractors had much experience of manufacturing complex metal shapes in such numbers; and secondly, Supermarine’s drawings left something to be desired – there simply wasn’t the detailed information in them required to produce these items accurately, and Supermarine didn’t provide much help. This problem found an uncomfortable echo when Australian shipyards began fabricating hull modules for the Royal Australian Navy’s new class of Air Warfare Destroyers and found that the drawings supplied from ship designer Navantia, via the Australian project office, didn’t contain sufficient information for the Australian yard concerned to build the first block module properly.

This leads to the third major problem with the Spitfire program. In order to build them at the necessary production rate plans were made for Spitfires to be built at a so-called ‘Shadow Factory’ in Castle Bromwich, near Birmingham. The factory was built (slowly and by a surly, poorly managed and strike-prone workforce) and was to be managed by no less than Lord Nuffield, the founder of the Morris car company who was considered to be an expert in mass production. In fact, by the late 1930s Nuffield was well past his prime and his organisation had absolutely no idea about manufacturing aircraft. 

Indeed, according to Leo McKinstry in his outstanding book “Spitfire – Portrait of a Legend”, one motor industry veteran at Castle Bromwich was horrified at the suggestion the Spitfire should be made of aluminium. “Make things with aluminium?” he exclaimed. “Not bloody likely! That stuff is OK for pots and pans but we are going to make things to beat the Nazis. We’ll use iron.” Another Castle Bromwich manager insisted the Spitfire’s wing should be redesigned so that it was easier to manufacture: “The air would not know the difference between straight and curved leading edges.”

In both cases the Air Ministry had to insist the aircraft was built according to the drawings. In the end, Beaverbrook wrested control of Castle Bromwich from Nuffield, put a team of Vickers managers into the place and progress began to be made. But the planned production rate of 100 aircraft a month wasn’t achieved until well into the summer of 1940. Had the Spitfire gone into full production on anything like the original schedule it’s likely RAF Fighter Command’s frontline squadrons would all have been equipped with this aircraft and the toll wrought on the Luftwaffe during the summer of 1940 would have been even higher. But that’s all by the way.

The fourth major problem with the Spitfire program wasn’t strictly a Spitfire problem at all. It was a whole of industry problem that exists today in Australia, the UK and, increasingly now in the USA. It was, quite simply, that the British aviation industry didn’t now how to build large numbers of aircraft. The Air Ministry and RAF kept a number of aircraft companies alive during the 1920s and ‘30s by awarding small contracts to design and build experimental aircraft, or relatively small numbers of new aircraft. There was some progress in the design and construction of aircraft and aero-engines, some of it driven by challenges such as the Schneider Trophy races which stimulated innovation by designers across Europe and North America. But until the menace of Nazism took shape and cast its shadow across Europe there was no great official appetite for ground-breaking innovation and massive numbers.

Jeffrey Quill sets out the problem quite elegantly in his book “Spitfire – A Test Pilot’s Story”.

“The awkward truth was that in 1936 no firm in the industry was in a position to respond effectively to a sudden demand for great expansion of its production capacity and simultaneously make great strides in the technological field… With hindsight, the initial shortcomings of the [Spitfire] subcontracting scheme can only be attributed to the same basic cause – namely that for years the industry had been starved of orders and could barely keep its factories in business on the orders it did receive. So where were the experienced and capable sub-contractors to be found on the fringe of a half-starved industry? They simply did not exist.”

There’s a lesson here for any government that professes a need for a proficient, and efficient, aerospace or defence industry.

The long and short of it is that the Spitfire was a great design, so far ahead of its time that the British aircraft industry had to learn (slowly and painfully) a whole new set of techniques for manufacturing it in the quantities required. And once its initial manufacturing problems were overcome the Spitfire became the pre-eminent fighter of its generation. Its only real peers were the Focke-Wulf 190, Messerschmitt Bf109 and the Rolls-Royce Merlin-powered variants of the North American P-51 Mustang. The Hawker Hurricane, to which the RAF and the free world owes a massive debt, was a stopgap in technical terms and never close to the Spitfire and Bf109 in performance terms, but it was exactly right for its time and made history in its day.

So what does all this have to do with the F-35 Lightning II?

Only this: the Spitfire, like the F-111, was a fundamentally good design that pushed the boundaries of technical knowledge and manufacturing practice. It’s arguable that these aircraft should have been designed (or re-designed) so they were easier to manufacture. One could make the same argument for the F-35 family. That’s to miss the point, in all cases: these aircraft were designed they way they were because they had a very specific job to do. Changing the design to make the aircraft easier to build would in each case have compromised its combat effectiveness. Every aircraft design represent some sort of compromise in any case, but in the case of the Spitfire, whose design is now well documented, RJ Mitchell refused to compromise on aero-propulsive performance – and quite rightly. The F-111 was designed for sustained high speed flight at low altitude in all weathers, day and night. If it couldn’t do that then there was no point to the aircraft – despite its technical challenges in the early days nobody sought to compromise its performance as a way of making the challenges easier to surmount.

The F-35 is designed to be stealthy, to be a respectable (though not necessarily a stellar) performer and to endow its pilot with massive situational awareness. Leaving aside the difficulties of integrating an avionics and sensor suite of unprecedented capability and complexity, mass producing a stealthy aircraft involves manufacturing technology challenges which no aircraft company has ever had to master before. There can be no doubt these challenges will be mastered, in time. Meanwhile, the battle the F-35’s advocates need to win is for the hearts and minds of the customers, and this become harder to win the longer the battle goes on. The examples of both the Spitfire and the F-111 show that persistence brings rewards.

There is one significant difference between the Spitfire and the F-35. The Spitfire’s manufacturer had no idea, in the early days, how to build a modern all-metal fighter in large numbers; and it lacked sub-contractors who understood new technologies and the techniques associated with new materials. The same is not true of the F-35. The consortium building it – Northrop Grumman and BAE Systems, led by prime contractor Lockheed Martin, with Pratt & Whitney developing the F135 engine – has an industrial pedigree that embraces collaborative, multi-national projects dancing on the leading edge of aerospace technology. The international supply chain, fed from eight different countries, isn’t carrying any freeloaders in a technical sense. But the technical challenges remain: a new construction process; a new engine and, for the F-35B variant, a new propulsion system; and a new weapon system based on a suite of avionics and sensors that’s never been integrated on such a scale before, and certainly not in a single-seat aircraft.

It’s wrong to suggest that the F-35 is the Spitfire of the 21st century, but the history of the Spitfire program should give heart to the team developing the F-35.