Chapter 1. Introduction
2
lead the new vehicle to break again the Land Speed Record. The material produced during the
realization of the first Buckeye Bullet was useful for the determination of the main parameters of
interest, and as a start point for the design of the new vehicle.
At this moment, several aspects need to be analyzed, in particular:
1) Struggling to obtain a reduction in weight, the adoption of composite materials for the
chassis construction can allow the team to obtain a more resistant vehicle while, at the same
time, the overall weight can be reduced. Finite Elements Analysis offers itself as the better
tool for the evaluation of the benefits of the introduction of composite materials and to
perform a comparison between various chassis configurations.
2) In order to evaluate the dynamical behavior of the vehicle and to analyze the forces that acts
on the suspension during the race, a multibody model of the vehicle can be developed, using
a commercial multybody software, ADAMS. The model will include all the aspects that
influence the vehicle dynamic and will be very useful even for the stability analysis of the
vehicle.
3) Due to the unique characteristics of this very particular kind of race a unique suspension
system has been designed. The suspension behavior needs to be analyzed, in particular, the
suspension can be modeled in ADAMS and inserted in the complete vehicle model.
4) During the race the suspension system is subject to loads that comes from the road. Then the
parts that make up the suspension need to be analyzed under the load conditions using again
the Finite Elements Analysis, to verify structural integrity.
1.3 Thesis overview
This thesis is divided into 6 chapters including this introduction. Chapter 2 gives an overview of
land speed racing and of the Buckeye Bullet 1. A sample Matlab simulator is further explained, in
order to show how much a reduction in overall vehicle weight can bring benefits in terms of speed
and acceleration. Chapter 3 gives an overview on the main suspension system actually adopted in
the automobile construction and also provide some basic notion concerning tires and the standard
mathematical models used for the calculation of the forces developed by the tire-road interaction.
Chapter 4 focuses on the comparative analysis of some different chassis configurations, starting
from the original BB1 spaceframe chassis to more advanced solutions that imply the use of
composite materials. The analysis is performed using a commercial finite element software. An
Chapter 1. Introduction
3
optimal chassis configuration is found, and then around this chassis all the main parts of the vehicle
are modeled, in order to find vehicle inertial properties.
Chapter 5 focuses on the dynamical analysis performed on the vehicle. First, a unique suspension
system, especially designed for the BB2 is presented. Then, the spring and damper to be used are
dimensioned. Then a four degrees of freedom analytical model has been developed, with the aim of
obtaining a quick, reference solution to evaluate the load that enter the suspension when the vehicle
hits an object. A complete multibody model of the vehicle is then developed, using ADAMS and
the simulation of a bump impact is performed again, leading to results very similar to the ones
obtained with the analytical model.
Chapter 6 focuses on the finite element analysis of the suspension. The peak load determined with
the dynamical analysis is applied to the structure, to verify structural integrity and to give
suggestion to the designer on how optimize the shape of the suspension, allowing weight reduction.
Chapter 2. Background and overview
4
CHAPTER 2
Equation Chapter 2 Section 2
BACKGROUND AND OVERVIEW
2.1 Introduction to Land Speed Record
Land speed record racing is a particular kind of race in which the vehicles that participate race not
each against the other but each one against a common enemy: time. There are several classes of
vehicles that every year try to beat the world record, ranging from motorcycles, to solar vehicles, to
jet propelled vehicles like the Thrust SSC (Figure 2.1) which is actually the world fastest vehicle,
detaining a speed record of 1227.85 Km/h (763.035 mph), obtained in 1997 by Andy Green in the
Black Rock Desert, USA.
Figure 2.1: Thrust SSC, the World fastest vehicle.
The official history of land speed starts in France, where in 1898 Gaston de Chasseloup-Labat,
reached the “top speed” of 63,14 Km/h (39.24 mph) driving his car, the “Jeantaud”.
A turning point in the history of LSR was when the FIA (Federation Internationale de
l’Automobile) became the world’s governing body for Land Speed Racing and set precise rules to
obtain the Record. So, to get the world record is necessary to follow FIA rules, while, obtaining US
national record only require to follow the specifications of SCTA (South California Timing
Association) which is the national body recording the US speed records.
Chapter 2. Background and overview
5
FIA rules actually prescribe a double race on a seven miles track, in two opposite directions. The
seven miles track is used as illustrated in Figure 2.2.
Figure 2.2: Land speed record layout.
The first two miles are used to accelerate the vehicle, while the last two are used for vehicle
deceleration. The vehicle speed is measured in the central part of the track, and for each one of the
three miles that constitutes this part the entrance and exit speeds are measured. Then an average of
the entrance and the exit speed is calculated, and then again an average of the three averages
obtained is done. If the fastest average speed over one of these miles exceeds the standing record,
the vehicle is qualified for the return race. The vehicle is then rotated and another race is done, in
the same manner as the previous. A further average is computed and the result speed is the one
valid for the record. A rule prescribe that the return race must start necessarily within an hour from
the end of the first run, and, in this hour (which is a very short lapse of time) the team must perform
all the required operations on the vehicle, under the penalty of the disqualification. US records rules
are nearly the same, except for the time between the first and the second run, that in this case is of
four hours. These relatively short periods of time between the two runs puts significant design
considerations for the teams, especially for the ones who are running with electric vehicles and that
have to, in addition of the standards operations on the vehicle, recharge the batteries for the second
run. In the US the most famous place for LSR race are the Bonneville Salt Lake Flats in Bonneville,
Utah (Figure 2.3) , a huge expanse of salt, 75,00 miles (about 120 Km) long and 35 miles (about 56
Km) wide, where every year teams meets trying to achieve the new LSR.
Chapter 2. Background and overview
6
Figure 2.3: The huge expanse of salt at Bonneville, Utah.
The salt flats are located 10 miles East of Wendover, Utah. At one time, the course covered over
100,000 acres (about 40 hectares) and the salt depth was over 36 inches. Today the salt flats is
closer to 26,000 acres (about 10 hectares) and the salt is three to four inches deep and in some
places the mud shows through the salt. The old "International Course" was 13 miles long. Currently
we have only seven miles left to race on. The "SAVE THE SALT" campaign has been successful in
that Riley Company has been ordered to start a resalting program designed to put .4" of salt back on
the race course each year. Eventually racers expect to get some distance back to may see once again
the very fast cars breaking records. Another place in the world used for setting LSR is the Lake
Gairdner, Australia, which is located about 100 miles North of Adelaide. Lake Gairdner is over 100
miles long and 20 miles across with salt over 4 feet thick in places. Racers say the salt is "perfect".
The last spot used by the racers is Black Rock Desert, Nevada, located 100 miles North of Reno,
Nevada. The lakebed is a dried alkaline. When dry enough to run on, about September to
November, it looks parched, cracked and dusty. When the wind blows, and it really blows hard at
times, the visibility drops to near zero. The course can be as long as 19 miles. There is considerable
rubble on the surface so defodding is necessary. The Bureau of Land Management requires a bond
and cash fund set up for their use while a race team is utilizing the lakebed. The surface acoustics of
the dirt appears to have aided the supersonic run by the Thrust SSC by absorbing the sound shock
wave rather than reflecting it back to the bottom of the vehicle.
Chapter 2. Background and overview
7
2.2 Brief History of the Land Speed Record
As stated above, the first LSR was set in France, in 1898, by Count Gaston de Chasseloup-Laubat.
All he wanted to do was prove that his automobiles worked well and for him this was one way to
prove it. What the Count started, and he didn't know, was a challenge which has sparked the
imagination of millions of children thrilled with the concept of speed, but has lured only a select
few adults who have accepted that challenge over the last century.
The land speed record came to the United States in 1904 when Henry Ford wanted to prove to the
world that his cars were built better than anyone else's in the world. On January 12th at Lake St.
Clair, Michigan near Detroit, Mr. Ford bounced his Ford Arrow (Figure 2.4) across the frozen lake
to reach an average speed of 91.37 mph (147.04 Km/h). He remarked of the run, after retirement,
that it had scared him so bad that he never again wanted to climb into a racing car. With the news of
his record spread around the country, his new car company got a much needed boost at becoming
one of the most successful automobile manufacturers in history.
Figure 2.4: Henry Ford driving his Arrow.
The 100 mph barrier was quickly broken later in 1904 when the land speed record returned to
France. Louis Emile Rigolly was one who loved racing wheel-to-wheel with an opponent and is
considered the world's first true drag racer. After being defeated in a standing mile race by Paul
Baras, Rigolly decided to do something spectacular to save face; he flew through the kilometer at
103.55 mph (166.64 Km/h) and dazzled the crowd.
While there were many others who claimed the record at progressively faster speeds, the next
notable level of achievement went to Malcolm Campbell of England. On February 4, 1927
Chapter 2. Background and overview
8
Campbell drove the Napier-Campbell Bluebird to 174.883 mph (281.447 Km/h) on the beach at
Pendine Sands. The Bluebird was the first car built strictly for breaking the land speed record;
making it unique.
Breaking the 200 mph barrier was the accomplishment of Major Henry Seagrave. He drove the
Golden Arrow (Figure 2.5) to a new record speed of 231.446 mph (372.340 Km/h), again at
Daytona Beach, Florida. What made this car unique is that it is on record as the least used car;
having been driven a total of only 18.74 miles. Seagraves was later knighted by Queen Elizabeth for
his achievements. Sir Henry also attempted to capture the water speed record in his Miss England II
when his boat hit a log in the water and capsized, killing Seagrave and mechanic, Victor Halliwell.
Figure 2.5: Seagrave’s Sunbeam Car.
The competition between Campbell and Seagrave brought down the 300 mph barrier when Sir
Malcolm Campbell, also knighted for his achievements by the King of England, averaged a speed
of 301.129 mph (484.818 km/h) at the Bonneville Salt Flats, Utah on Sept. 3, 1935 with a much
more powerful V-12 Rolls-Royce engine in the Campbell Rolls-Royce Bluebird.
John R. Cobb of England was driving the Railton Mobil Special in his attempt to break the 400 mph
barrier, when on Sept. 16, 1947 he managed to average only 394.196 mph (634.196 kph) at the
Bonneville Salt Flats, Utah. Cobb too, attempted to claim the water speed record in his Crusader on
Loch Ness, Scotland, but lost his life on Sept. 29, 1952 when it flipped and exploded.
The 400 mph barrier was finally broken by Mickey Thompson of the U.S. on Sept. 9, 1960. Driving
the Challenger 1 powered by 4 Pontiac V-8 pushrod engines producing 700 hp each, he reached an
average speed of 406.60 mph (654.359 Km/h) to return the record to the U.S. after belonging to
Englishmen for 32 years. Donald Campbell, son of Sir Malcolm Campbell, followed in his father's
footsteps and claimed the land speed record on July 17, 1964 at Lake Eyre, Australia. This record
was the only one set outside the U.S. during the recent period of records. His Bluebird-Proteus CN7
reached an average speed of 403.135 mph (648.783 Km/h) using a gas turbine engine. He lost his
life attempting to break the 300 mph barrier on Coniston Water in his jetboat Bluebird.
Chapter 2. Background and overview
9
The early '60s was the beginning of a new era of land speed vehicles. Through most of this decade
the claim to the title "The Fastest Man on Earth" went back and forth between two Americans; Art
Arfons and Craig Breedlove. Their speeds crept up gradually from just over 400 to 600 mph. Art
Arfons achieved a maximum speed of 576.553 mph (927.873 kph) in his Green Monster on the
Bonneville Salt Flats, Utah on November 7, 1965.
The record set by Bob Summers, the following week in 1965, was to signal the sunset of an era in
land speed racing. On November 12th the Goldenrod, what the purists consider one of the few
wheel powered land speed vehicles from a bygone era, reached an average speed of 409.277 mph
(658.526 Km/h).
Future vehicles would be free wheeling; driven with jet or rocket engine thrust, with the exception
of one. Three days later, Craig Breedlove drove his Spirit of America - Sonic 1 to 600.601 mph
(963.364 km/h) with a 15,000 lb. thrust jet engine blazing behind him. After surviving a near fatal
crash with his earlier model Spirit of America - it crashed by losing its chutes & rolling over a burm
and into a canal - Breedlove had triumphantly returned to break the 600 mph barrier which had
eluded him for so long. Five years would pass before a new challenger would up the record. On
October 23, 1970, Gary Gabelich drove the Blue Flame, a unique engine propelled by Liquid
Natural Gas, to 622.407 mph (998.341 km/h).
Figure 2.6:Gabelich's Blue Flame.
Gabelich's record stood unchallenged for 13 years, until on October 4, 1983 Richard Noble of the
U.K. would drive his Thrust 2 to a new record of 633.468 mph (1016.083 km/h), but this time on
Black Rock Desert in Nevada instead of at Bonneville. For 19 years the Americans had dominated
the land speed record books, but now the British have returned to reclaim it once again.
The Budweiser Rocket Car used a sidewinder missile to push it up to Mach 1, but didn't meet the
international requirements for going into the record books.
Chapter 2. Background and overview
10
In 1983 Richard Noble flew his Thrust II low over the Black Rock desert to set a new record of 633
mph. It was learned later, as reported in a BBC two part special about the ThrustSSC Project, that
had Noble gone only 7 MPH faster, the Thrust2 would have gone airborne; resulting in certain
death. Noble's record stood unchallenged for 13 years.
Then, in October of 1997, Andy Green, an RAF fighter pilot, driving for Richard Noble in the
Thrust SSC did the unthinkable by breaking the sound barrier at Mach 1.02. The speed of sound is
estimated to be roughly around 740 mph, but varies depending on temperature and elevation. In the
process, he set a new two way average record run of 763.035 mph. While the ThrustSSC stands
alone in its class of land speed record vehicles to this day, there are those who are setting their
sights on getting the record back; working quietly and patiently until their time comes to take a
crack at the record and hopefully reclaim it once again. Other vehicles will, no doubt, join this elite
class some day with even faster speeds.
2.3 Brief history of the electric land speed record
The history of the Electric land speed record begins in 1968 when Jerry Kugel (Figure 2.7), on his
“lead wedge” set the record at 138 mph, driving a car weighting 1015 Kg and powered by a 120
horsepower AC motor, fed by lead acid batteries.
Figure 2.7: The "Lead Wedge"
Chapter 2. Background and overview
11
Then, in 1971 the record was set by the Silver Eagle, that, with a power source of 180 rechargeable
silver-zinc cells and a 102 hp motor, achieved to set 14 US national records an 7 international
records, with a top speed of 152.598 mph.
The next LSR was set by Roger Hendlund and his battery box, who reached the speed of 175 mph.
Then the record was beaten in 1997 by the Lightning Rod, a streamliner that was the first eletric
vehicle achieving to beat the 200 mph barrier, setting a world record of 215.3 mph.
In 1991, the LSR was then broken by the White Lightning (Figure 2.8), a streamliner powered by
two electric motors, each one providing 150 Kw, and a complex 420 volt battery pack, consisting of
6120 nickel-metal hydride AA sized batteries. On each of the land speed record runs, the power
pack were required to run full power for about 90 seconds as 20 intricate packs containing 6,120
batteries (each battery weighing 1/10th of a pound) push a powerful electric charge through the
motors. Team Orion of Switzerland modified the batteries to permit them to be discharged
simultaneously, thus creating the necessary power to accelerate quickly. The record was set at
254.229 mph, and that remained uncontested for 13 years until the advent of the Buckeye Bullet 1,
actually the world’s fastest electric vehicle.
Figure 2.8: The White Lightning.
Chapter 2. Background and overview
12
2.4 Overview of the Buckeye Bullet 1
Figure 2.9: The Buckeye Bullet 1.
The story of the Buckeye Bullet (Figure 2.9) finds its roots in The Smokin’ Bullet, an electric
vehicle that a student team of OSU has operated since 1993 in a university contest named Formula
Lighting, with greats results. In order to break the old Land Speed Record, hold by the White
Lightning, this team began, in 1999, to design a streamliner vehicle, with this sole purpose in mind,
and they achieved this success in October 2004 at the Bonneville Salt Lake Flats, setting the new
LSR at 271.737 mph and so making the Bullet the world’s fastest electric vehicle. Moreover, with is
speed on a timed mile of 321.834 mph the bullet is actually the fastest vehicle on hearth, beating the
speed record hold by the TGV, the French high speed train. Let’s make an overview of the BB1
configuration.
The BB1 weighs over 4300 lbs, and is 31 ft long. Its power source consist of 5 packs of NI-Mh
batteries (for a total voltage of 900 V) that provide power to a custom-built triphase AC motor,
supplied by Shoemaker Industrial Solutions, which develop a power of over 500 HP. The DC
current coming from the batteries is transformed in a triphase AC current by means of a Saminco
inverter.
The power coming from the electric motor is then transmitted through a 5 speed manual gear box to
a differential and then to the rear wheels. Figure 2.10 provides a functional overview of the BB1.
Chapter 2. Background and overview
13
Figure 2.10: BB1 functional overview.
2.4.1 Chassis
The chassis of the BB1 is developed around the driver’s cage, and consists of a tubing made of
4130 Chrome-Molybdenum steel (.95% Chromium, .2% Molybdenum).
This material, often used in the construction of racecar chassis, provides a good hardness, low
brittleness and a good toughness. The chassis (Figure 2.11) consists of four section: the driver’s roll
cage, the front suspension section the rear suspension section and the battery section. The driver’s
cage (that must comply to SCTA specifications, and that is inspected by technical commissaries
before the race, was made of tubes having a diameter of 1-5/8” (4,1cm) and a thickness of .095 in
(0.24 cm) as the tubing of the rear suspension part. The other section were made with a smaller
tubing, having a diameter of 1 ¼” (3,17 cm) by a thickness of .083 in (0,21 cm).
Chapter 2. Background and overview
14
Figure 2.11: Buckeye Bullet 1 chassis.
2.4.2 Front suspension system
The design goal, in the conception of the BB1 suspension system, was to create a four wheel
independent system, that means that each wheel can travel in is motion without affecting the others
(see chapter 3 for an overview on suspension systems). The design of the front suspension was an
hard problem, because of the very limited amount of space available for the housing of the whole
system and of the necessity, for safety reasons, to completely eliminate the bump steer (the change
in the steer angle of the wheel as a consequence of his vertical travel). This was a primary concern
because, even if the surface of the salt lake is flat enough, there are always present some salt pot,
and a steer input that is not coming from the driver could be very dangerous for a vehicle which is
traveling at such high speeds. Bump steer was eliminated designing a double A-Arm suspension
having the two arms parallel and equal in length. Another task that was performed was the
elimination of the king pin and caster angles. This was achieved using equal length arms and setting
the upper and lower ball joints vertical from each other. To provide feedback to the driver,
mechanical trail was introduced in the suspension, simply putting the spin axis besides the king pin
axis (Figure 2.12).
Chapter 2. Background and overview
15
Figure 2.12: BB1 front suspension.
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