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Andy Green's Diary: Building Bloodhound

In February 2014 I was speaking to a British Airways audience at their annual flight safety day.  My aim was to tell them how we set the first supersonic record in 1997 with the Thrust SSC and to talk about how we planned to get to 1609km/h with the Bloodhound, safely.

It was also a useful chance for us to show our homework to a group of industry safety specialists – in this case 200 commercial pilots and aircraft engineers.  If there is something that we haven’t thought of yet, they will find it!  From my point of view, this is one of the great strengths of Project Bloodhound.  The more expert advice we have, the more confident we can be that we’re going in the right direction.

As I told the BA group, the requirements for a safe Land Speed Record are really very simple:

1.    Keep the car shiny side up.
2.    Stop before the end of the track.  

Our aerodynamics engineer Ben Evans gives a great summary of this 6 year marathon in ‘The Path to Predictability’.  As he points out, we’ll be testing the aerodynamics on every run, and only going faster when we know that the car will stay on the ground.

STOPPING? THREE OPTIONS...

Stopping the car is slightly different. For the whole time that the car is accelerating, I can always throttle back if something doesn’t look right: more speed is always optional.  However, when the car comes bursting out of the measured kilometre at 1600km/h, slowing before the end of the track has just become compulsory.  The end of the track may be eight kilometre away, but the car is doing a kilometre every 3.6 seconds, so that’s really not very far.

Stopping is compulsory. Getting this bit right is so important that Bloodhound, uniquely, has three options for stopping. The first is air-brakes, which can be deployed gradually from 1290km/h. 

Alternatively, we’ve got a brake parachute that will generate about nine tonnes of drag at 1080km/h.  And if there’s a problem with the chute, then we’ve got a second identical brake chute, just in case. 

The air-brake mechanism is squeezed under the jet engine.  Both sides must deploy at the same time, otherwise I will be going round in circles.  Twin hydraulic pistons drive a single slider plate, which in turn is connected to both air-brake doors so that both move together.  If that is difficult to picture, then have a quick look at the air-brake animation on the Bloodhound website.

The finished slider has just been delivered to our technical centre in Bristol. Want to come down and see it for yourself? 

Join our 1K Supporters’ Club and we’ll invite you down for one of our open days. 

Key to stopping the car from 1290km/h with the air-brakes is getting them to deploy at the right time.  Too fast, and we’ll overstress and damage the doors.  Too slow and we won’t stop quickly enough.  In addition, they need to be ‘fail safe’ – in other words, if we lose electrical or hydraulic power on the car, then the air-brakes need to deploy automatically (because slowing down is still compulsory, even if you’ve got problems). 

ACRYLIC LAYERS

We’ve received three hydraulic control blocks from, which will take care of the air-brake deployment, at the right time, with or without power. One less thing to worry about. 

The front upper wishbones were delivered by 4Front Racing. These are fabricated in steel, in multiple parts, and then welded, heat-treated and ground.  The upper wishbones transmit the front wheel loads to the chassis. We only need a few more suspension bits before we’ll be able to conduct the first test-build of the whole front suspension.

The front suspension assembly bolts to the front of the cockpit monocoque. The screen is made in layers and then bonded together, with each layer formed from a block of solid acrylic which is heated and stretched. 

The 25mm screen sits just in front of the Bloodbound's  jet engine intake and shapes the supersonic airflow before it gets there. The angle of the screen is very shallow, to generate the right shock wave pattern, and this oblique angle means that I’ll be looking through 50mm of solid plastic to see where I’m going. The screen will need to be optically perfect, so this first sample is an important test of the process. 

RACE CAR X10

The jet engine relies on an ‘airframe mounted accessory drive’ or ‘AMAD’ gearbox. The AMAD contains the engine starter turbine, as well as the electrical generator and hydraulic pump that will power Bloodhound. All of this will be supported by the AMAD bulkhead, which weighs only 5.3kg but will be supporting more than 100kg of gearbox.

Bloodhound engineering is like a normal race car but with everything multiplied by 10. 

We’re also just about to exceed 20 000 names on the tail fin.  Want to join us at 1609km/h?  Put you name on the fin and you can!
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