Pump up the volume
Whatever the form of propulsion unit, achieving speeds of 1000mph or more tends to use a lot of fuel.
Rockets are probably the thirstiest engines around. Take the space shuttle. At take-off the two solid booster rockets would drink their way through 11,000 lbs of fuel A SECOND. The main shuttle engines, which kicked in after the solid booster rockets were discarded, burned a further half-million gallons of liquid propellant to bring the shuttle up to its maximum speed of 17,000mph, a velocity that was reached around 6 minutes after launch.
So all in all the shuttle wasn’t the most economic form of travel known to man…
When it comes to earthbound forms, things can still get a tad expensive when you want to go fast. Take the Bugatti Veyron. At full chat it consumes petrol at a rate of 2.15 miles per gallon. Which means it can only cover around 56 miles, pedal to metal, before you need to fill’erup. And that would be just 12 minutes after you’d floored it. Hardly long enough to eat your Yorkie (mind you, not sure we’d be taking a hand off the wheel at 250mph plus!).
But when you’re talking fuel consumption, the Veyron is a pussycat in comparison to what will hopefully become the fastest dog in the world. The Bloodhound SSC.
All being well, next year the team hope to take it to the limit by blasting the Bloodhound to 1000mph or more across the Hakskeen Pan in South Africa. And that, as you can imagine, will take a bit of oouuumf (that’s a technical term for a shed load of power). And similar to the space shuttle, it’s going to take two types of engine to take it to the limit. A rocket engine to act as a booster and a jet engine ‘borrowed’ from a Eurofighter to provide the main push.
Now as you might imagine this will require a touch of fuel to light the blue touch paper. Which is where an item called the Auxilliary Power Unit or APU comes in. Normally this would take the form of a rather unsexy box of engineering whose sole task is to do what it says on the tin. Deliver auxilliary power. However in Bloodhound the pump is a tad more exotic because they’ve ‘borrowed’ a 550bhp Jaguar Supercharged V8 engine to fulfil the purpose. And guess whose spark plugs are OE fitment on that engine?
So there we have it. While the Bloodhound SSC powers its way into the record books, the APU will need to deliver the power that drives the rocket oxidiser pump, which will supply 800 litres of peroxide to the rocket in just 20 seconds. Or put another way over 9 gallons every second. Which is a lot.
But without the Jaguar Auxilliary Power Unit sparking on all eight cylinders the Bloodhound, and its ground based pilot Andy Green, will be going nowhere fast. Or at least not fast enough to break the 1000 miles an hour barrier. Proving once again that performance and reliability are at the heart of going fast, whatever you drive.
Published on 30th August 2016