Rocket propulsion was invented by the Chinese 800 years ago as a firework. And promptly proved that if you show a military mind a toy which shrieks and shoots up into the sky – why, the next thing you know you have a weapon research programme going. And when you have a weapon programme you will inevitably arrive at bigger rockets. And when you arrive at bigger rockets, then eventually some brave soul will step on stage with a new notion of how to utilise them…

For example, to move a man.

Around about the time Columbus is busy discovering America, a Mandarin called Wan Hu orders 47 rockets to be attached to a sort of semi-throne chair, plus two kites. He then straps himself into the chair and orders the rockets to be ignited. History is a trifle vague about the exact chain of events over the next few seconds, but is unanimous in recording Wan Hu’s more or less instant demise.

The subsequent history of rocketry, if not always quite so discouraging, does tend to prove that this can be a dangerous game. In the early 1800’s Colonel William Congreve invents a stabilised missile – a rocket tipped with a warhead – which is briefly tried out in the Napoleonic War, the idea being that the fearsome roar of a mass rocket-launch will firstly spread terror and the subsequent detonations spread mass destruction. Mass destruction it never achieves, but terror it does rather well – the only slight drawback being that the troops it terrifies are mostly our own, since ‘stabilised’ turns out to be a very considerable misnomer, a Congreve rocket being perfectly capable of getting somewhere near its apogee, inventing the word ‘aerobatics’ a century before its time, and returning briskly towards its progenitors rather than the enemy.

Rocketry, since then, has progressed. But is still a dangerous game.

BLOODHOUND will have a rocket on its back. A new, purpose-designed rocket called the Falcon which is being manufactured at this moment.

So why a rocket?

Well, the short answer is that despite being 800 years old, the rocket is still the most powerful engine known to mankind. By a long way. For example a rocket motor can produce more thrust than a jet engine of five times its weight and size. And a rocket, unlike a jet, does not require an aerodynamically inconvenient forward-facing gaping hole somewhere on the vehicle through which to suck in air....

Which is not, of course, the whole story. Very far from it. Bear with me.

Broadly speaking, there are three kinds of rocket engine: liquid fuel, solid fuel, and hybrid, which means a combination of liquid and solid.

Of these – again, broadly speaking – liquid fuelled rockets are the most efficient. They do, however, have one or two slightly disconcerting downsides. Such as they often need to be tanked up by fuels at very high pressure and very chilly temperatures indeed. And these fuels can be highly corrosive. And highly toxic. And since the whole principle is that when the two chemical mixes come together in the combustion chamber they instantly combust, it is slightly important that they are not allowed to mix – not even a drop – during the fuelling-up process.

The first mass manned use of liquid-fuelled rockets happens in 1944, when Germany produces the Messerschmitt 163 Komet, the world’s first rocket-powered fighter. The bi-fuelled 163 outperforms every other aircraft in the sky by a huge margin, blasting from take-off to 40,000 feet in three minutes, and winding up to nearly 700 mph in level flight. There are, however, certain hitches. One is that the thing carries only seven minutes fuel, and thereafter becomes a rather attention-grabbing high-speed glider. This the elite Luftwaffe pilots assigned to Komets can cope with to a degree – but what really drives them to the Schnapps of an evening is the 163’s unique propensity for blowing up. It is not uncommon for Komets to blow up while being fuelled. They will also blow up on take-off, or on landing if the few remaining dregs of fuel are jiggled about too much. This last is particularly disheartening since the 163 lands not on wheels but on a skid under the fuselage, a crudity which undeniably tends to promote jiggling. As, of course, does getting the glide approach slightly wrong and whacking the thing through a hedge.

The second type of rocket, solid fuel, is light, compact, stable until ignited, and even has a long shelf-life – all of which makes it ideal for weaponry such as missiles, where the minor detail that once you’ve started it up you can’t stop it is neither here nor there. (In fact I gather there are ways to stop a solid rocket burning, but rocket scientists regard these methods as having ‘serious safety implications’ – which means that normal mortals would prefer to be at least a mile away and preferably horizontal behind a blast-shelter with their fingers in their ears).

The third option, the hybrid rocket, is somewhat more civilised. It has solid fuel and a liquid oxidiser, so at least you can shut the thing down at any time by turning off the liquid flow.

Not, however, that the word ‘civilised’ can really be applied to any rocket, for the one thing most rockets have in common is that they cannot be throttled by the pilot or driver.

(Again, this is not entirely true. You can design a liquid or hybrid rocket to be throttle-able, but for a one-off project the R & D timescale is too long, the cost is prohibitive unless you have just sold a family heirloom such as, say, Saudi Arabia, and worst of all the mechanisms required will add weight and complication.)

In BLOODHOUND, thrust can be pre-adjusted to some extent by varying the fuel pump speed – but that does not change the fact that there is no gingerly pressing the loud pedal and accelerating in your own sweet time – you hit rocket-ignition and WHAM, you’ve got the lot, instantly, like it or not. I thus find myself fascinated by BLOODHOUND’s Falcon rocket – and indeed, by the whole combined power-pack. The combination of rocket and EJ200 jet will produce 47,500 lbs of thrust at peak – roughly in the order of 130,000 bhp, or say 400 Ferraris at full chat.

In 1970 Gary Gabelich raises the LSR to 622 mph in a beautifully-designed rocket car called The Blue Flame, using a thrust of 13,000 lbs. Legend says that he hugs the car and talks to it each time before he gets in. In 1983 Richard Noble ups the record to 633 mph in Thrust2 with an Avon jet of 17,000 lbs of thrust. He doesn’t hug the car, but hauls himself out and immediately gets on his mobile phone to find sponsors to fund the fuel for the run after next. You want to define mental stress – try doing that.

In 1997 Andy Green drives Thrust SSC to 763 mph, just over the speed of sound, using two Rolls Royce Spey jets totalling 40,000 lbs of thrust.

The power progression is most plain to see – 13,000 lbs, 17,000 lbs, 40,000 lbs….

Weight of the vehicle has its effect. But the main reason for this increasing power requirement is…. drag. Aerodynamic drag.

The family Drag has many children with different names. Profile drag, form drag, skin friction, parasite drag, interference drag, induced drag, base drag, shock wave – you name it. Doesn’t really matter what you call it, because the important thing is that, subsonically at least, all drag except induced increases with the square of the speed.

If you propel a house-brick at 300 mph it may produce, say, 500 lbs of drag. So you need 500 lbs of thrust to keep it moving. Double the speed to 600 mph and the drag quadruples – so now you need 2,000 lbs of thrust to keep it going. Push it into the transonic region and the drag spikes even more…..

These are immutable laws. But what you can do is re-mould your brick into a long thin smooth javelin of the same weight so that it disturbs less air in the first place – so that, say, it only produces 50 lbs of drag at 300 mph. And therefore only requires 200 lb of thrust at 600 mph instead of 2,000 lbs.

This is schoolboy science stuff – or is it?

The javelin is obviously long and thin. And keeping the frontal area to a minimum is obviously of prime importance. But what can make the Chief Designer of an LSR car testy is the fact that every other science involved requires internal space – space which will make the thing grow fatter given half a chance. And the javelin inevitably has warts anyway. It has to have wheels, which stick out. It has to have aerodynamic control surfaces – which stick out. It has to have a cockpit. It has to have air intakes, which stick out a lot…..

Legendary designer Ron Ayers crunches the numbers, looks into his highly-experienced soul for guidance, and comes to the conclusion that even two Eurofighter engines will not do the 1,000 mph job. Two jets mean two major air-intake warts on the javelin plus a considerable weight penalty – no, it won’t do. Break the existing record, probably – but 1,000 mph?

No.

Which leads Ayers back to rockets, of which he has vast experience, and which most importantly do not require big warts on the javelin. Re-enter Richard Noble, complete with leotard, searching for rocket expertise…..

Richard finds one Daniel Jubb.

Now all of the Bloodhound Team are very special people, so it is invidious to single out any one person. But Jubb is a singular person. Just as you don’t meet many Richard Nobles or Andy Greens in a lifetime, so you don’t meet many child prodigies, either. Jubb builds his first rocket at the age of 5, a few years later joins up with his grandfather to start a rocket research and build company, at 13 quits school because it isn’t teaching him anything new – he having from the age of 9 been getting up at 0600 every day to watch Open University – and devotes himself to running the company and designing rockets. By the end of his teens the company, Falcon Projects, has become Anglo-American, designing and building military and civilian rockets for US, British and Australian customers.

Nowadays he is a dapper figure with a moustache that looks like the front view of a B52. He could easily have just walked off the set of a Dr Who episode, but is in fact one of the most respected rocket scientists in the world.

Of course, he is older now. All of 24 years old, to be precise.

You have to ask, how does any kid do that?

The short answer is that I have not the faintest idea, having spent my own schooldays with my fingers stuck together with model aeroplane glue until becoming slightly distracted by an odd phenomena called ‘girls’.

But Dan Jubb did it. And Richard Noble talked to him. And Dan Jubb became enthused, designed the Falcon rocket for BLOODHOUND, built and tested a small-scale model of same – a common practise in rocket development – and now the build of the big version is well advanced. Cost so far – about £1 million. So regard this Dr Who character Jubb as a fairly major sponsor already….

(As an aside, Dan chides me gently for calling the rocket ‘Falcon’, it not in fact having a formal name yet. He tells me with a straight face which I regard slightly suspiciously that he refers to it as the ‘18” HTP:H.T.P.B/AP/AL Hybrid’. I try saying this a few times and trip over my own teeth. So forgive me Dan if I herewith informally name it ‘Falcon’ just for the moment in honour of you and your company, and also because I can actually spell it).

And so, of course, problem solved. Dump the idea of jet engines and simply use two rockets, yes? No draggy jet intakes poking out of the javelin, engines a fifth of the weight and a fifth of the size but producing more power – no contest, right? The BLOODHOUND team considered that idea for quite a while.

But not right. Remember I said bear with me.

Two things.

The EJ200 jet drags in its own oxygen at the front and requires about 600 lbs of (basically paraffin) fuel for its roughly 30-second burn.

The Falcon rocket does not suck in air and so has to supply its own oxygen from within its own fuel. So its fuel weighs four-and-a-half times the jet fuel. And takes up several times the space. And has to be chosen rather carefully to suit the purpose, because it seems that all oxidant rocket fuels have their snags, so it becomes a question of which snags you can live with most.

There is a trend in rocketry nowadays to use laughing gas – N20 – because it is stable, cheap, and readily available. The BLOODHOUND team considered this but rejected it partly because it is not the best oxidiser in the world, and partly because they discovered a 1930’s scientific paper which suggested that N20 might go off pop – well, bang, big-time, in fact – if it was pressurised to more than 13 bar. Since they planned to pump in the oxidant at 76 bar, this could be a slight disadvantage.

Since that decision there have been a number of big bangs at rocket sites which were using N20. Richard Noble is convinced the BLOODHOUND team had a lucky escape in opting for High Test Peroxide (HTP).

Me? I know very little about it. High Test Peroxide sounds like something you could turn 500 girls very blonde with, if it didn’t shrivel their hair off altogether. I gather that its major snag – and you have to pick your snags – is that the slightest contaminant during fuelling or anytime else can cause it to decompose into superheated steam and oxygen, which sounds to me like another recipe for an interesting bang.

Moreover, the HTP has to be delivered by a pump shifting a tonne of of the stuff at 1,100 psi in 22 seconds. And the pump – the 12 cylinder race-car engine – is still more weight and has to have fuel itself…

Aahh….

So not quite so efficient, yes?

Well, yes and no. Remember the fuel-weight is gone in 22 seconds – so the thrust-to-weight ratio increases hugely towards the end of the burn. And Dan Jubb can adjust the fuel-grain and oxidant pump-speed so as to start the rocket-burn at 22,000 lb thrust and finish it at 27,500 lbs – in simple terms, whacking up the power just when it’s needed, at the point of maximum aerodynamic drag.

The second thing…

Two rockets might be more powerful. But two rockets would gollop up nearly three tons of fuel – which quite apart from the weight would take up more room – and would also require a second 800 hp fuel-pump.

And above all the driver would have no control over the power other than by shutting one or both engines down completely.

Hmmm…

This is in fact the sort of thing a chap could talk himself into after a couple of beers – especially if he is not personally going to be the guy strapped into the thing. After all, what’s so different? You wanna do a work-up run with a jet, you don’t go to full power, right? So you wanna do a work-up run with rockets, you simply cut ‘em off early, right? Same difference, right?

The BLOODHOUND design team do not have a couple of beers before they convene. After much sober consideration the uneasy frowns and pursed lips of caution win the day, and the decision goes to the more controllable option.

Falcon Rocket and Eurojet 200, you are now man and wife, and let no person rent you asunder.

Dan Jubb is not the slightest bit phased. One of his objectives is to see rocket science re-enter the options available in British higher education. He is deeply critical of the axing of Britain’s Black Arrow satellite launching system in the early ‘seventies, pointing out that the UK was the only country in the world to successfully launch a satellite, pat itself on the back for so doing – and then suddenly abandon the whole programme. Commercial possibilities, higher education – the UK Government just dumped the lot.

It made no sense, says Dan….

I am slightly heartened; let me admit, to find a chink in the prodigy’s armour. He actually thought a Government decision ought to make sense. Bless the boy.

But you never know. People like Noble and Jubb are difficult to stop. Maybe a World Land Speed Record will force rocket science back onto the UK university curriculum…..

We shall see.