Page last updated at 11:44 GMT, Wednesday, 16 September 2009 12:44 UK

Bloodhound diary: Rockets firing

RAF fighter pilot Andy Green intends to get behind the wheel of a car that is capable of reaching 1,000mph (1,610km/h). Powered by a rocket bolted to a Eurofighter-Typhoon jet engine, the Bloodhound car will mount an assault on the land speed record.

Wing Cmdr Green is writing a diary for the BBC News Website about his experiences working on the Bloodhound project and the team's efforts to inspire national interest in science and engineering.

WHERE ARE THE BRAKES?
bloodhound air brakes
The 50cm airbrake panels lift from the rear to slow Bloodhound to 600mph

The recent news about the "coke bottle bombers" highlights a slightly scary fact about rockets.

The bombers' plan for blowing up several airliners (and the reason that we can't take drinks through airport security any more) was to use concentrated hydrogen peroxide (known as high test peroxide, or HTP) in soft drinks bottles.

A third of a litre of HTP is, apparently, enough to blow a hole in the side of an airliner. So when the rocket fires in Bloodhound SSC, and we pump a hundred times this much into the rocket every second, we're going to have a fairly huge explosion.

Daniel Jubb and his team have promised that when they test-fire Bloodhound SSC's rocket at the end of the month, this will be a "controlled" explosion. I can't wait to see how they get on. Hope it won't actually blow up..... I'll let you know.

Desert search

We're still looking for deserts to run Bloodhound SSC. After last month's visit to the US, none of the deserts there appear to be fit for purpose.

We're still looking at one remote site in Australia, and I've passed details on to our Australian competitor, Rosco McGlashan, in case he can use it (or at least go and see what it's like, since he's closer than I am!).

Meanwhile, I'm still keen on Verneuk Pan in South Africa, but it has a surface full of tiny bits of stone.

At high speed, the front wheels will kick these stones up, and then they'll hit the back of the car at a closing speed of 1000 mph; in effect, it's like machine-gunning Bloodhound SSC at point blank range.

You can see how this might be a problem. Let's hope that we can find a way to fix it.

We're still refining the surface shape of Bloodhound SSC, to see if we can improve the aerodynamic balance of the car.

One simple fix is to switch over the jet and rocket, putting the jet on top. This is the last major decision we have to make before starting to build the car - we're nearly there.

Finding the brakes

You would expect that the biggest challenge for a 1,000mph car would be accelerating to top speed.

Then again, with 12 tonnes of controlled explosion from the Falcon Rocket, ably assisted by nine tonnes of thrust from a Eurofighter engine, perhaps you wouldn't be surprised to learn that going fast is only half of the problem - slowing down is the rest of it.

We need to stop a five tonne car from 1000 mph in about 4½ miles, so the team has opted for parachutes and airbrakes to make sure that I don't end up going on a long cross-country drive at the end of the record run…

We don't have a parachute supplier yet (if you know a company that would like to help with the drag chutes, please get in touch!) but we're already working on the airbrakes.

Question is, how big do they need to be, and what will they do to the airflow at high speed? Swansea University's super-computers are working on this one as well.

No sweat

I went to the World Aerobatic Championships at Silverstone this month, where several surprising things happened.

We sold out of Bloodhound sweatshirts (a result of typical English summer weather) and sold a whole load of 1K Club Memberships - a lot of people were jumping at the chance to get involved in the most exciting motorsport challenge that they'd ever heard of.

Given that we were selling these memberships at a race weekend at Silverstone, that said a lot about Bloodhound.

Sbach extreme 300
The Sbach "Xtreme" is the world's fastest production aircraft

I was also lucky enough to take a quick spin in the new Sbach 'Xtreme', the world's fastest production aerobatics aircraft.

It is so responsive that it felt "twitchy". Unfortunately, I made the mistake of saying this to Alan Cassidy.

Alan is the "god" of British aerobatics (a role he's inherited from Brian Lecomber, who's now writing monthly updates for Bloodhound) and Alan quite correctly put me in my place: "There are no twitchy aircraft, only twitchy pilots".

The same is probably true of land speed record cars.

Thanks Alan, I'll keep working at it.

Silverstone was also the first time that I've been approached by potential sponsors asking me how they can invest in this project. Normally it's us pestering them for money. I've never had sponsors chase me before.

While we were at Silverstone, the rest of the Bloodhound team was at an education festival at Stoneleigh, Warwickshire. We've now got well over 1,000 schools across the UK signed up to the Bloodhound education programme, and it's great to see their enthusiasm first-hand.

balloon cars
Visitors to Stoneleigh's Imagineering Fair built and raced balloon powered cars

The Bloodhound stand was swamped by kids wanting to find out what we were doing and to try rocket-thrust racing for themselves, using the Bloodhound "balloon cars". Yet another clue that we're getting the message out to our audience - the engineers of tomorrow.

Who said that race cars only appealed to boys?

BLOODHOUND SSC
Bloodhound SSC
1. Titanium or composite wheels - rear wheels sit outside bodywork covered by aerodynamic fairings
2. Driver sits behind front wheels and in front of engine air intake duct
3. Carbon fibre bodywork for optimum aerodynamic performance, reaching top speed over 4.5 miles. Same distance required for stopping
4. Bloodhound powered by Eurofighter jet engine with hybrid rocket attached, enabling car to accelerate from 0-1,050mph in 40 seconds
5. Fins maintain stability and downforce to keep car on the ground
6. Air brakes slow car at highest speeds; parachutes slow car at mid-speeds; finally, driver halts car with carbon fibre wheel brakes



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SEE ALSO
Bloodhound diary: Pressure builds
23 Aug 09 |  Science & Environment
Bloodhound diary: Speed record
30 Jul 09 |  Science & Environment
Supersonic car targets 1,000mph
22 Oct 08 |  Science & Environment

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