When Andy Green attempts to break the land speed record in South Africa in 2015 his Bloodhound car will be showcasing an array of UK engineering excellence under its skin.
It was just over 15 years ago that Andy Green powered Thrust SSC to a shade over 763mph on Nevada’s Black Rock Desert to improve on his own land speed record. But when Green sets foot on South Africa’s Hakskeen Pan in 2015, breaking that record will not be enough. The plan is to shatter the record and top the 1,000mph mark with his Bloodhound jet/rocket hybrid. In early summer of 2015 the car will take to the runways of the UK’s Newquay airport before being flown directly to South Africa to start carrying out high-speed testing. That year the team will limit itself to breaking the land speed record before analysing the data and returning the following year with a fully hybrid rocket car to reach 1,000mph.
“The whole thing about this is the challenge,” Mark Chapman, chief engineer on the Bloodhound Project says. “If you wanted to just break the record, to get an 800mph car, then you could take ThrustSSC out of Coventry Museum, pimp it a bit and you could probably get that car to 800mph.
“There is such a leap to go from 760mph to 1,000mph, it is completely unknown. That is the whole ethos of this project as we are an educational project. It had to be genuinely difficult and challenging and this is why we are doing it.”
Rules of the game
Formula One has a rules and regulations book the size of a telephone directory, but the land speed record rules are four lines on a single sheet of A4. The car has to be driven; it has to be in full control of the driver; you have to do the run in two directions for a measured mile within an hour; and you have to leave wheel tracks.
For Thrust SSC assessors had to walk along the measured mile to check that there were indentations and that it had in fact stayed on the ground the whole way through. “For the speed we will be doing that is almost irrelevant as - although we will definitely stay on the ground - we will also achieve the air speed record as well in that we will go faster than any aircraft has at that altitude. Even if you had a jet fighter, there isn’t a jet fighter that has gone that quickly at that altitude before. We will travel about 25 per cent faster than the aircraft that we get the jet engines from, the Eurofighter Typhoon.”
It is almost six years since Chapman joined the Bloodhound project and in that time he has guided the project from a blank sheet of paper to the stunning car that is taking shape at the team’s headquarters.
That design has always been a moveable feast, evolving as expertise from suppliers is incorporated into the master plan.
The original plan was for a pure rocket car before it developed into a jet and rocket hybrid, but with a completely different configuration to what we see now. It had a split intake and was much longer, coming in at around 20m in length. The front wheels were tandem, one in front of the other, in an attempt to try and keep it as narrow as possible. “Myself and Brian Coombs, the lead mechanical design engineer, started on the same day,” Chapman says. “We spent the first couple of months trying to work with something that was better packaged as the original car was so big.”
The jet engine was always planned to be the Rolls-Royce EJ200, although initially they were not sure how to get hold of one. The original car had an MCT V12 normally aspirated engine, but as time went on that changed to a Cosworth F1 powerplant.
One of Chapman’s first tasks was to convert all the early work into CAD models to allow different configurations to be assessed as well as for stress and aerodynamic analysis to be carried out. The CAD work was undertaken on Siemens NX PLM software along with other packages for stress such as Altair HyperWorks.
“We carried out a quick six-week trade study between a whole range of different options,” Chapman adds. “Some were open-wheelers, some were with Andy Green in a very low-seated positions, others with him in a very upright position and some even had him in front of the front wheels.
Aircraft, racing car and spaceship
“It was almost starting with a clean sheet of paper then configuring the packaging adding Andy Green, two engines and the car engine into the space and seeing what kind of shapes we could come up with. Then we would do a sort of matrix on these concepts for stability for drag and different variables that we had to consider before coming up with a winner.
“Within eight weeks we had a car, which, if you squinted, looks much like the car we have now. The main difference is that after about a year we decided to swap the jet and the rocket. This solved dynamic stability issues; when the rocket was fired it would have buried the nose in the ground. Swapping the two engines around worked better because both those thrust lines straddle the centre of gravity and it made the car a lot more stable during the transition between pure jet and then combined jet and rocket at the same time.”
Free from the constraints of the traditional automotive platform or tooling restrictions, the team had only to worry about adhering to the most aerodynamically efficient form manageable. “It was all about juggling it, but function drove it,” Chapman says. “There were some early studies with chief aerodynamicist Ron Ayers where we were going back to 1950s and 1960s aircraft design where they were doing very low-drag transonic designs. Some of the car design has been driven by the research done at that time on what we call ‘anti-drag’ bodies.”
Unique, challenging, unconventional. The project has been labelled with these and many other metaphors, but it certainly requires a different way of thinking. The engineering team needs the ability to solve complex engineering problems, often without the safety net of industry practices. “This project is part racing car, part aircraft and part spaceship,” Chapman adds. “We have got a very wide range of people and with the skill set we need for this project people have dabbled in lots of different of things. We have guys who are ex-Williams F1, guys who are ex-rail systems, and it is much more about the engineering skill and gut feel of the people we work with.
“This project is simply so different that we need people who, either through breadth of experience or having worked on more unusual projects, have had those blinkers removed and are really prepared to think about unusual challenges.
“We have had some challenges on this project where it has been really hard to come up with any answer; we couldn’t see a resolution. We had to go back and look over the questions we were asking and then change those questions into something that we could answer and accepting compromise on certain parts of the vehicle.”
The team relies heavily on the expertise of suppliers - more aptly described as partners. For the companies involved in the project it is not about financial gain; the vast majority work free of charge or at a substantially reduced rate. For them it is about showcasing their talents outside the restrictive world of top-level motorsport, aerospace and defence where their achievements are hidden by non-disclosure agreements.
Challenges of speed
“We will shortcut a lot of what most companies will do. We have come up with the design, handed it to the manufacturer for design review and we try to get that process working an awful lot earlier to use their expertise and industry knowledge to influence how we design things.
“[Given that] we are not fixed to exactly what we have to do, if someone comes to us with an idea on how to change something we can adapt. We are constantly updating and releasing new designs and there is an opportunity for them to have their input.”
Unlike a Formula One team, which can take its car on the track and test endless parts at full speed, running on this project will be strictly limited. In fact the car will only ever go 1,000mph twice - maybe three times - in its whole life. “We will need to rely on a lot of computational methods. We have actually just completed, at AMRC, some testing for the pull rods where we tested them for fatigue and strain.
“But we can’t try out a 1,000mph run before we actually put Andy in the car so the whole run profile is built up of gradually increasing the speed, but then also using the data, as we get it off the car, to correlate our computational models.
“Every time we go a bit quicker we will then check the data off the car with what the computer predicts we should see, and provided they stay correlated we will keep increasing the speed. If they start to diverge we would then look at why this was happening, and then make the model better to reflect the reality of what we actually see and then use that as a way to predict what we expect to see moving forward again.
“The continuous process as we approach 1,000mph is to make sure that our computational model matches what we see in reality. It is very much that we will learn all this information to improve all the modelling and go forward with those.”
If they succeed in topping the 1,000mph mark it could signal the end of further record attempts as Chapman explains. “There is a limit. There are factors, like wheels, where there may be a point that you simply cannot make a wheel that will withstand the forces.
“However, the biggest problem is actually slowing the car down and finding a length of desert to allow the car to run on. It is relatively easy to accelerate quickly, but to slow the down is bigger challenge than getting it up to speed. You can’t use wheel brakes, you have to use air brakes and parachutes, and there is a limit to how much of a car you can open out into the wind and just relying on aerodynamics to slow you down.”
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