BLOODHOUND LAST

BLOODHOUND
1000mph Land Speed Record
Group 32 –Project 3

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BACKGROUND
The land speed record is the highest speed achieved by a person
using a vehicle on land.
The United Kingdom,with the exception of one year, held the record
between 1914 and 1963 until the United States took over and
continually improved it.
The UK was rapidly losing its reputation as an industrial giant in the
world and the loss of the land speed record was seenas another
national humiliation.
Acting against the tide of faltering national technologicaland
manufacturing prowess were the actions and motivations of a public
schooled army officer’s son, Richard Noble. UK national pride was at
stake and it needed a specialpersonto challenge the USA and return
to the top of the record books.
Against all odds,with the UK nation despondentlythinking it had
dropped off the leader board of technologicalnations forever, Richard
wrestled the record back from the USA driving the vehicle “THRUST
2” to 633.47 mphhimself in October 1983.

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National pride was restored to a degree.Modelling data after the
actual record run showed that if THRUST 2 had achieved another
6mph the car would have been airborne, disaster probably would
have occurred,and Richard Noble may have beenat risk of losing his
life.
Undisturbed by this near death experience, Richard planned to beat
the sound barrier in a car. He achieved this on October15 1997 in
THRUST SSC, although not driving this time, by achieving 763.035
mph. The driver was Andy Green, double first in Mathematics at
Cambridge University, RAF fighter jet pilot, and keen at his job.
Although exhausted by the challenge processes,particularly
financing the venture, Richard approached his aerodynamic guru,
Ron Ayers to enquire if a car could achieve twice the speed of sound.
Ron stated that Mach 1.4 (1065 mph) is the aerodynamic limit. Ron
was then asked if 1000mphwould be possible and he replied barely
probable.This was enough to spark a new challenge for Richard,
resulting in a new project “Bloodhound” was born. Andy Green was
again asked if he would like to drive which he gladly accepted.
The Bloodhound project counters UK culture’s lack of confidence in
technology, engineering, manufacturing, computerservices and
projectmanagement. As a result, the UK Governmenthas offeredthe
most technologicallyadvanced aero jet engine produced in this
country (Rolls Royce EJ200) and access to the European Space
Agency’s next generation (Nammo) hybrid rocket in return for
inspiring education.

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The Bloodhound project is most strikingly differentthan other Land
Speed Record attemptsdue to its emphasis on computermodelling
and it’s data acquisition. This enables the productionof computer
simulation “in silico” experimentation. This is aimed to reduce/
eliminate the need to guess,over engineer, be lucky and trusting
intuition in the build process.
WHY DO IT? Humans are obsessedwith speed.Who hasn’t taken
their car, motorbike,bicycle, athletic achievement to a limit above
‘safe”.Who wouldn’t want to commute to work at 1000 mph? Who
doesn’twant to see a car go faster than a single bullet? (We are in
Superman territory here). This is the stuff of legend and its associated
benefits of national pride and inspiration.
It should be noted that the USA, USA & Canada jointly, Australia and
New Zealand are all attempting to reach this summit of technology
while Bloodhound is developing. In everything the rest of the World
like to beat the UK so the competitionis real.

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INTRODUCTION
The task is to produce an Excel simulation of the Bloodhound land-
speed record.
The brief is to demonstrate the car reaching 1000 mph within the
regulation test distance of 4.5 to 5.5 miles and stopping safely within
12 miles.
The information is of interest to the projectas it explains the car’s
record attempt in mathematical terms. Forces can be calculated at
differentpoints of the modelto determine stressesand strains acting
on the car.
The Bloodhound website shows the “PerfectRun” in graphical form.
The vehicle is shown in the graph travelling at only 100 mph in the
first 17 seconds.Bloodhound is required to start slowly to avoid mud
and dust being thrown up and into the air intake for the EJ200 Jet
engine (Bloodhound website). We were unable to replicate this low
speed and achieve the record speed.External advice was sought
without success and an email was sent to JohnLanham @ UWE for
advice but no reply was received.

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ASSUMPTIONS and DATA
COLLECTION.
The Bloodhound project is to exceed 1000mphand claim a new land
speed record.It is also to educate and inspire the next generation of
engineers.Data has been collected from the officialBloodhound
website which supplies large amounts of information.
1. Mass
Mass is variable due to a fuel load of approximately 1500kg.Assume
consumptionat a constant rate. Some Jet fuel is required to turn the
car around for the second run. This action will also increase engine
cooling time and was adopted as the best solution. Suggestedby
Rolls Royce engineers.(Bloodhound).
Mass is as per the Bloodhound website (11- 4 - 2016)“Design
condition, full with fluids and driver” at 7786kg.Emptyof fluids but
including driver the mass is 6227kg.The car is presented as weighing
over 7,500kg in media presentations.The designtarget mass is lower
but there is no evidence to suggestthe car’s mass is less than the
designcondition given.

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2. Air Density
Equation for air density:
Rho (air density) = Pressure(pascals)
Rspecific(Specific gas constant) x T (absolute temp (k) )
Pressure
Range
m
b
915-
940
Typical limits of SA surface pressure
Ambient Air Pressure
range
m
b
970-
1040
Typical limits of UK surface
pressure
Figure A.
Figure A shows a comparisonof the South African (Hakskeen Pan)
and UK ambient air pressure ranges.
Altitude of Hakskeen Pan is 794m above sea level. Air pressure
reduces with altitude.
The temperature ranges due not vary greatly. According to Ron Ayers
and Steve Newey of Bloodhound,in a very preliminary look, it
suggestedthat top speed could be increased by 1 mph if the
temperature is reduced by 1-degree C. Air density is inversely
proportional to temperature and therefore also inversely proportional
to the Drag.
The temperature on the Record Run day will be as low as possible
and ideally lower than the 15C shown in the 1.225kg/m3 calculation.

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As there is no specific date given for the run, climatic conditions have
too much variance to suggestan Air Density calculation as an
alternative to the 1.225kg/m3 given however it is expected to be less
as in Bloodhound’s mediapresentations.
Assume air density (rho ) = 1.225kg/m3
3. RollingResistance.
The rolling resistance remained constant due to the variation in the
track surface and the need to steer the car using the wheels as
aerodynamic devices.
When the wheels are at an angle and in contact with the track the
rolling resistance is increased.
The surface of the track is a natural mud layer on bedrock.The
thickness of the mud varies so the frictional forces will vary with
inconsistencies of the surface and the possibilityof the wheels
touching bedrock.
Rolling Resistance will contribute 11% of the braking force.
(Bloodhound)
Over 900 mph the shock wave effects will have a reduction on the
rolling resistance at the wheels giving a skating feel to the driver.
(Bloodhound)
Supersonic aerodynamic effects are ignored due to complexityof
calculations. i.e. Krr v = Zero.
Assume Rolling Resistance is constant throughout journey.

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4. Thrust- Jet and Rocket.
The engine data was acquired from the Bloodhound website.
The website reports that it is necessaryfor the car to start slowly as
this will avoid disturbed surface elements being accelerated into the
jet engine inlet. Any contaminants in the engine could affectits
performance.
The Rocket engine can run for 20 seconds before all fuel is spent.
(Bloodhound)
The PerfectRun states the need to throttle back the jet engine
showing a degree of driver choice to achieve run requirements.
5. Drag coefficient
Frontal area figures are taken from the Bloodhound website as 1.937
m2.
The drag coefficientis shown on the Bloodhound website as 1.32.
The Cd of 1.937 figure given refers to Area * Cd = 1.32.
Therefore,Cd = 1.32/1.937 = 0.6815.

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This is a high figure compared with other vehicle types however
Bloodhound expect52% of the braking to come from aerodynamic
drag.
6. Braking
Bloodhound’s ability to reduce speed is a safety as well as a
performance factor.
As mentioned above 52% of negative Thrust will come from
Aerodynamic Drag and 11% from Rolling Resistance.(Bloodhound)
Air brakes are controllable by the driver and when fully extended
have the aerodynamic effectof doubling Area and Drag coefficient.
(Bloodhound).
A parachute with a diameter of 2m (Bloodhound)can be deployed by
the driver at below 650 mph. The Drag coefficientof 0.51 was given.
Wheelbrakes are also controllable by the driver and can be deployed
below 200 mph.
Braking coefficients have been chosento remain below 3g for the
model.In reality the driver has a great deal of control over the braking
process to reflectreal life events.
Driver safety is the paramount concern over ALL other factors.The
braking capabilities are within parameters for all predicted
eventualities. For example, the vehicle will be stop within 12 miles by
using a braking combination of air/vehicle, parachute/ vehicle, or
air/parachute (Bloodhound).

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In a perfectrun the driver will have options to make the run more
comfortable forhimself by removing g-forces and/orto allow for the
bestpossible engine recovery scenarios e.g. both engines will need
to cooldown prior to preparation for the return run.
Part of Andy Green’s, Bloodhound’s driver routine during the run is to
counteract g-forces by exercising differentmuscle groups. As an ex
fighter jet pilot and a current acrobatic plane pilot he has no difficulty
coping with 3g physiologicalstressesand they are well within his
personal limits. He is able to regularly fly the accelerationpattern of
the record run in his acrobatic plane to practice and acclimatize his
body. (Bloodhound)
7. Wind.
Assume there is zero wind.
8. General
The test area of 4.5 to 5.5 miles is puzzling as the course is 12 miles
long. Bloodhound is required to turnaround and complete the course
from the oppositedirectionwithin one hour. The original starting point
is 12 miles away so if Bloodhound was to begin the return journey the
measured mile would be at 6.5 to 7.5 miles and the car would need to
stop in 4.5 miles. If the measured mile was to alter position between
runs this could alleviate the problem but I doubt that sensitive
recording equipmentset up to record an historic event with the goal
so close to the emotive 1000 mph would want to be moved.

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On the Bloodhound website “the sound of Bloodhound SSC” a 1000
mph run shows the measured mile at the midpointi.e. 5.5 – 6.5 miles
on 17 June 2014.
MODEL
Newton’s Second Law states that the acceleration of an objectas
produced by a net force is directly proportional to the magnitude of
the net force,and inversely proportional to the mass of the object.
This is represented by the equation F = mass * acceleration.
The net forces are the Tjet and Trocketacting in a positive direction
with Aerodynamic Drag and Rolling Resistance (sonic and subsonic)
acting in a negative direction.
Fnet = Tjet + Trocket – 0.5*Cd*A*Rho*v^2 – mgCrr – krrv
As shown above Fnet = ma so:
Thrust – Drag – Rolling Resistance = m * a
Rearranging for acceleration:
a = (Thrust – Drag – Rolling Resistance)/ m

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Elements of Model
Thrust = Tjet + Trocket
Tjet (maximum) = 60kN to 90kN (with afterburner applied)
[Bloodhound]
Trocket (maximum) = 122kN (Bloodhound)
Cd = Drag coefficient= 0.6815 (no units) (Bloodhound)
A = 1.937 m2 (Bloodhound)
Rho = 1.225 kg/m3 (Given in question)
V = velocity (varies) (m/s)
m = Mass of vehicle, fuel, and driver. = 7786 kg reduces as fuel
consumed. (Bloodhound)
g = gravitational force at earth’s surface = 9.81 m/s2
Crr - Rolling resistance
1200N(given) = 7786 * 9.81 * Crr
Crr= 1200 / (7786 *9.81)
Crr = 0.0157(no units).

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SI units are used in all cases but converted to imperial to give
historical comparisonwith formerrecords.
EXCEL SOLUTIONS
For ease of comparison all five graphs (figures 1,2,3,4, and
5) have the time period for the horizontal axis representing
the 120 seconds (2 minutes).
Figure 1 : Bloodhound Record Run acceleration/ time graph.

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In figure 1 Bloodhound’s acceleration peaks at 25 m/s/s and troughs
at -29.6 m/s/s.
The stepping of acceleration values from the start (time =0) is due to
an increase in thrust to the jet engine followed by the afterburner
being turned on resulting in a further increase in thrust.
The acceleration then reduces due to the increase of aerodynamic
drag by the increased resultant velocity.
The Rocket Engine is then switched on causing an instantaneous
increase in accelerationto the maximum of 25 m/s/s. The
Aerodynamic Drag reduces the acceleration to 0.5g over time.
The Rocket Engine is then turned off causing an instantaneous loss
of thrust. The Jet Engine is turned off 1 second later resulting in zero
thrust to Bloodhound.The Aerodynamic Drag at the measured mile
peak velocity stage at 179839N. This large negative thrust causes a
large change in acceleration in the negative direction to – 30 m/s/s.
The Aerodynamic Drag is dependenton velocity squared. Therefore,
as velocity is reduced by acceleration in the negative direction so
does the Aerodynamic Drag reduce to – 16.5 m/s/s.
The Air brakes are applied at 750mphwhich increases the frontal
surface area by a factor determined by the driver (up to doubling the
-40.0
-30.0
-20.0
-10.0
0.0
10.0
20.0
30.0
0 20 40 60 80 100 120 140
Acceleration(m/s2)
Time (seconds)
a (m/s2) v t (s)

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original area) which is a factor of Aerodynamic Drag. A resultant
increase in negative acceleration to -21.7 m/s/s is achieved. The drop
in velocity causes the acceleration in the negative direction reducing
as before.
At around 550 mph at 49.4 seconds the parachute is opened.This
adds a further addition to the frontal surface area resulting in
increasing Aerodynamic Drag which increases acceleration in the
negative direction from -12.1 m/s/s to –22.8 m/s/s.
With Air Brakes functioning and driver controllable, the parachute
inflated, Bloodhound is in a controlled decelerationto the finish. As
there is zero thrust the driver uses the vehicle wheel brakes to bring
Bloodhound to rest at the required point. The smoothlong curve of
the graph in the final section reflects this control
Figure 2 : Bloodhound Record Run velocity/ time graph.
Figure 2 shows Bloodhounds velocity against time. The two bold
vertical lines representthe measured mile. Bloodhound is required in
-200.0
0.0
200.0
400.0
600.0
800.0
1000.0
1200.0
0 20 40 60 80 100 120 140
Velocity(mph)
Time (seconds)
The area between the two bold vertical lines is at a distance of 4.5 miles and 5.5 miles.
This represents the measured mile area for the final analysis.
v (mph) v t (s)

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the Record Run to reach an average of 1000 mph during the
measured mile section.
A straight line would reflectconstant acceleration. As we have seen
in the figure 1 (acceleration) analysis the acceleration varies with
thrust in a positive directionand by velocity and surface area in the
negative direction.
The rocket and jet engines are switched off and within the measured
mile section. The Aerodynamic Drag (52%) and Rolling Resistance
(11%) are designed to contribute to braking performance.
The remaining braking is controlled by the driver to produce a smooth
velocity reduction enough to roll to the finish line.
Figure 3 : Bloodhound Record Run distance/ time graph
0.0
2.0
4.0
6.0
8.0
10.0
12.0
0 20 40 60 80 100 120 140
Distance(miles)
Time (seconds)
Distance (miles) v t (s)

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Figure 3 shows the distance travelled from the start by time. A
straight line would show constant velocity. The velocity varies to the
acceleration changes due to the changes in thrust and aerodynamic
drag. Ideally Bloodhound would finish at the 12 mile mark.
The acceleration graph (figure 1) was deliberatelyformed to achieve
1000 mph average velocity within the measured mile and to apply the
air brakes and parachute early in case of failure.
Andy Green’s first option is the air brakes which are independently
hydraulically operated.They could have been applied earlier/ later/
opened more / opened less or not at all in the event of total failure.
Andy’s next option is when to use the parachute which will be
dependenton the air brake functionality and the agreed ideal stress
parameters on the system.He will want to apply the parachute to
reduce the stress on vehicle brakes but not too early otherwise the
vehicle will not reach the finish at 12 miles.
Arriving at the 12-mile point is an important task for Andy to achieve.
At the finish many supportcrew will be waiting to prepare the car for
its compulsorysecond run. Recovering the vehicle would waste
valuable time.
The Jet engine could be restarted to provide thrust but this would not
be a preferred optionas a major problem for the supportcrew is
reducing engine temperatures to enable working and refueling.

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Figure 4 : Bloodhound Record Run mass/ time graph
In figure 4 mass is shown as decreasing during the run.This is to
reflectBloodhound using stored fuel to power the rocket and jet
engines.
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
0 20 40 60 80 100 120 140
Mass(kg)
Time (seconds)
Bloodhound mass (kg) v t (s)

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The Rocketfuel has three elements:HTP (H2O2) Oxidant, HTPB
Fuel, and HTP Propellant. The total consumed mass is shown as
963kg Oxidant, 181kg Fuel, and 776kg Propellant = 1920 kg (total
consumed).
Some Propellant mass not included in the above figures is not
consumed as it is required to prevent the pumps from running dry.
This mass is included in the dry car mass.
By comparisonthe EJ200 Rolls Royce jet engine has a total fuel
mass of 302 kg for a Record Run time of 39 seconds with some left
over to turn Bloodhound around for its second run.
An internal combustionsupercharged Jaguar V8 engine has replaced
the Cosworth V8 Formula engine to pump Oxidant into the rocket
engine. This engine runs on unleaded fuel for the 20 seconds of
operation. The unleaded fuel mass is not given on the Bloodhound
website foreither engines. The engine needs to run at 18000 rpm to
pump the oxidant quick enough but only for the 20 seconds and is
therefore likely to be a relatively small mass. This fuel consumption
and its effecton overall mass has not beenconsidered.
Figure 5: Bloodhound Record Run Aerodynamic Drag + Rolling Resistance/
time graph.

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In figure 5. Aerodynamic Drag and Rolling Resistance peaks at
180000 Nas shown. This is why Ron Ayers, Bloodhound
aerodynamic expert stated that Mach 1.4, around 1065 mph is the
maximum velocity for a wheeled vehicle.
The drag increases with velocity until the velocity peaks at 1052.4
mph. Due to thrust being reduced and within a second completely
stopped an acceleration in the negative direction occurs.Velocity and
Drag reduces as a result until at at 44 secondsthe air brakes are
turned on. They have variable frontal area increase capability and
drag is increased. With zero thrust and only acceleration in the
negative direction possible(and planned for) the resultant velocity
reduction factor becomes larger than the surface area increase factor
and the drag reduces again until the parachute is deployed at 49.4
seconds.
The drag immediately is increased due to the increase in frontal
surface area given by the parachute. Zero thrust, positive drag and
0.0
20000.0
40000.0
60000.0
80000.0
100000.0
120000.0
140000.0
160000.0
180000.0
200000.0
0 20 40 60 80 100 120 140
CdandRR(N)
Time (seconds
Aerodynamic Drag + Rolling
Resistance (N) v t (s)

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positive rolling resistance means the acceleration continues in the
negative direction. The resultant reduction in velocity also reduces
drag until the vehicle brakes are used to “fine tune” the drag by
increasing rolling resistance under the full control of the driver.
SUMMARY
The Bloodhound project was of vague interest prior to this exercise.
Using a mathematical modeland observing the effectof quantifying
values to a variable has been an adventure.
The adventure aspects of the project as a whole, the honorable
pursuit of promoting education and awareness, the personalrisk to
life from the participants, and the good news selling of a “better
Britain” are all positive.
The project has been subjectto considerable time delays from 2012
to sometime this year.
As mentioned in the background sectionin this document the project
has been extensively computermodelled.Our results differfrom the
PerfectRun despite our best efforts.With more data at their disposal

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creating better computational fluid dynamic modelling it would be very
interesting to see how Bloodhound achieved their velocity/
acceleration PerfectRun graph.
As some data on the website is from 2012 there is a need to update it
to give more confidenceto our modelling. The mass variables in
particular would be of interest.
Experimental data to confirm the modelwould also be welcome.
We are confidentthat the projectwill be successfulin beating the
1000mphbarrier and eagerly look forward to the day of the run.
REFERENCES.
Bloodhound. (2012). Vehicle technical specifications. Available:
http://www.bloodhoundssc.com. Last accessed 12th April 2016.
BloodhoundSSC. (2012). The team. Available:
http://www.bloodhoundssc.com. Last accessed 12 April 2016.
Green, Andy. (2013). FIA World Speed record.. Available:
BloodhoundSSC. (2012). The Perfect Run. Available:
Noble, Richard. (2008). The Adventure. Available:

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Wing Commander Greene, Nic. (2012). Physiological effects of
driving Bloodhound. Available: http://www.bloodhoundssc.com.
Last accessed 12 April 2016.
Green, Andy. (2012). Training for 1000 mph. Available:
Green, Andy. (2012). The challengers. Available:
http://www.bloodhoundssc.comp. Last accessed 12 April 2016.

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