Go-Kart's
Design And Construction
Based On Theoretical
And Experimental
Findings
By
Ho Yoong Chow
Thesis submitted to the Faculty of Engineering,
Universiti Malaysia Sarawak
As a partial fulfillment of the requirement for the Degree of
Bachelor of Engineering with Honours
(Mechanical Engineering and Manufacturing System)
2001
Acknowledgements
my deepest
I would
like to express
making
this paper such a success.
paper would not be completed
First and foremost,
Syed Shazali,
appreciation
Without
for those who helped me in
their support
and assistance,
this
as it is and in such short term.
I would like to thank my supervisor,
who had provided
me a truly understanding
Mr. Syed Tarmizi
of scholarship
and
support along this paper.
Next, my fellow group mates, Mr. Tan Tang Chin, Mr. Fam Kueh Szue,
and Mr. Rowdy Ignatius, who have been very cooperative and supportive to rne.
I would like to say thank to our CNC laboratory technician, Mr. Masri b.
Zaini and Mr. Rhyier a/k Juen, who supplement me the skill of operating and
handling the machine, tools and devices.
By this opportunity, I would also like to thank Mr. Opec Kadri, owner and
Managing Director of Cosama Sdn Bhd, and Mr. Wan Azlan Shah, lecturer of
Polytechnic Kuching, who generously provided me with knowledge for building a
go-kart.
Finally, I would also like to thank my family, fellow friends and those
involved in completion of this project and documentation.
Ho Yoong Chow
UNIMAS, 2001
iv
Table Of Contents
Pages
Letter of Approval
i.
Approval Sheet
ii.
Project Title
iii.
Acknowledgements
iv.
Table of Contents
V.
List of Figures
viii.
List of Tables
X.
List of Graph
Abstract
XI.
Abstrak
XI1.
1
2
1
Introduction
1.1 History of Go-Kart
1
1.2 Go-Kart Today and Future
2
4
Literature Review
2.1 Introduction
4
2.2 Chassis Design
4
2.2.1 Frame Construction
5
2.2.2 Unit-Body Construction
7
2.2.3 Space Frame Construction
8
2.3 Platform
8
2.4 Chassis Materials
9
2.4.1 Galvanized Steel
10
2.4.2 High-Strength Steel
10
2.4.3 Chrome-moly
11
2.5 Evaluating Go-Kart's Chassis
11
2.5.1 Chassis Squareness
11
2.5.2 Length
12
V
2.5.3 Steering Position Alignment
2.5.4 Kart Straightness
2.5.5 Other Jobs
2.6 Basic Go-kart's Chassis Theories
2.6.1 Frame Construction
2.6.2 Side Bite
2.6.3 Torsion Bars
2.6.4 Ackerman Steering
2.6.5 Kingpin Inclination
2.6.6 Spindle
2.6.7 Scrub Radius
2.6.8 Caster
2.6.9 Caster Stagger
2.6.10 Camber
2.6.11 Toe-in
3
Methodology
3.1 Data Collection From Research
3.2 Data Collection From Interview
3.3 Mathematical Analysis
3.4 Chassis Design Generation
3.5 Go-Kart Construction
3.6 Initial Chassis Setup
3.6.1 Chassis Baseline
3.6.2 Chassis Alignment
3.6.3 Initial Setup
3.6.4 Rear Axle
3.6.5 Rear Axle Mounting
3.6.6 Spindle Installation
3.6.7 Front And Side Bumper
3.6.8 Seat Installation
3.6.9 Floor Pan
vi
3.6.10 Weight Distribution
4
5
Results
4 *1
3.7 Chassis Material Testing
45
3.8 Evaluation Of The Final Product
47
And Discussions
48
4.1 Frame Design
48
4.2 Chassis Baseline Measurements
49
4.3 Kingpin Inclination of Chassis
53
4.4 Spindle Angle
53
4.5 Scrub Radius
54
4.6 Caster Setting
55
4.7 Caster Stagger
56
4.8 Camber
56
4.9 Weight Distribution
57
4.10 17 Degree Method
59
4.11 Chassis Material Evaluation
60
4.12 Photo Gallery
65
Conclusion
And Recommendations
71
74
References
Appendices
A-1 Sample Go-Kart Chassis From Specter Racing Chassis
A-2 Sample Technical Drawing
A-3 Go-Kart build by students of Polytechnic Kuching
A-4 Go-karts found in Cosama Sdn. Bhd.
A-5 Kart Setup Output
A-6 Tensile Properties For Some Engineering Metals:
Engineering Properties.
A-7 Technical Drawings of MechTech-Initial
vii
List Of Figures
Pages
1.1
One of karting pioneer,
Rathmann
Xterminator
Don Boberick
prototype
riding the first
kart. (Extracted
2
from
http: //www. vintagekarts. com)
1.2
Don driving the "Drone" at the Rose Bowl parking lot 1957.2
(Extracted from http: //www. vintagekarts. com)
2.1
Ladder
frame
from
5
Perimeter frame of a common vehicle. (Extracted from
6
Automotive
2.2
of
a
common
vehicle.
(Extracted
Chassis Systems, p. 2)
Automotive Chassis Systems, p. 2)
2.3
(a) Unitized construction, the small frame members are for
7
Many
he
and
suspension
components.
of
engine
support
vehicle would attached the suspension components directly
to the reinforced sections of the body and do not required
the rear frame section; (b) separate
body and frame
construction. (Extracted from Automotive Chassis Systems,
p. 2)
2.4
Torsion bar of a common car.
17
2.5
Results of Ackerman Steering test taken at various angles of
18
the steering.
2.6
Common Ackerman steering of a go-kart.
19
2.7
Kingpin inclination.
20
2.8
Scrub radius.
21
2.9
Torque arm caused by scrub radius.
22
2.10
Caster Angle.
23
2.11
Camber.
24
2.12
Toe-in.
25
3.1
Sample chassis found in Cosama Sdn. Bhd.
27
3.2
Go-kart built by students of Polytechnic Kuching.
28
viii
3.3
Kart Data for Windows 95/NT used in calculating the weight
29
distribution on a go-kart.
3.4
Kart Setup by Kyle Davidson.
3.5
Designing software for generating
30
drawing of the new
31
chassis- AUTOCAD R14.
3.6
Worktable.
32
3.7
The worktable specially constructed for building the chassis.
33
3.8
Process of heating up the steel pipe for bending process.
34
3.9
Bending process of the frame.
34
3.10
Figures showing
steel pipes which have been welded
35
together to make up the outer frame of the chassis.
36
frame.
3.11
Completed
3.12
Weight distribution
test (without driver).
43
3.13
Weight distribution
test (with driver).
43
3.14
17 Degree Method testing.
44
3.15
17 Degree Method testing.
44
3.16
G. I. pipe testing setup.
46
4.1
Spindle Angle.
53
4.2
Caster angle of the front right wheel.
56
4.3
Results obtained from Kart Data 2000.58
ix
List Of Tables
Pages
4.1
Weight distribution
4.2
Results of 17 Degree Method testing.
59
4.3
Result of G. I. pipe testing.
60
4.4
Modulus of Elasticity
61
of the go-kart.
57
List Of Graph
Pages
4.1
61
Deflection versus Load.
X
Abstract
The best way to evaluate a functioning go-kart would be testing its performance
under various conditions and points. Therefore, a new go-kart called MechTechInitial was presented in this report.
Mech Tech -Initial was constructed based on the common go-kart size
found in the market but with slight difference in the frame design. MechTechInitial's chassis was built using steel pipes, bent and welded together, with
consideration to the position of engine position, braking system, steering system,
seat position and many more.
Other go-kart's components such as engine, seat, steering wheel, brake
system, bumper and wheels are mounted to the chassis to test the performance.
The chassis
dimensions
were taken for further testing and future
distribution
17
Among
tests
the
wheel,
and
each
weight
on
applied
are
reference.
degree method.
xi
Abstrak
Cara yang paling berkesan untuk menguji persembahan sebuah 'go-kart' adalah
dibawah pelbagai keadaan dan kedudukan. Maka, satu 'go-kart' yang diberi
nama MechTech-initial telah dihasilkan untuk laporan ini.
Mech Tech- Initial telah dibina berdasarkan ukuran go-kart yang lazimnya
dijumpai di pasaran dengan sedikit perbezaan dalam rupabentuk rangka. Cesi
Me ch Tech-Initial dibina dengan menggunakan paip-paip besi yang dibengkok
dan dikimpalkan
bersama, dengan mengambilkira
kedudukan enjin, system
dan
kerusi
kedudukan
sebagainya.
pembrekan, roda steering,
Komponen-komponen
go-kart yang lain seperti engine, kerusi, roda
steering, brek, bampar dan roda kemudiannya dipasang ke atas cesi untuk
menguji persembahannya.
Dimensi cesi diambil secara teliti untuk tujuan kajian lanjutan dan rujukan
masa depan. Antara kajian yang dijalankan adalah penyebaran berat pada setiap
roda dan metod 17 darjah.
X11
1
With
Introduction
the
automobile
Malaysian.
completion
racing
of
Sepang
has become
Consequently,
International
Formula
One
Circuit,
one of the most popular
sports
among
go-karting
begin to gain more attention as there
is no age limit to this sport. Furthermore,
low investment,
making it affordable
from public retailer or constructing
1.1
go-kart nowadays
requires very
by most people to either purchasing
one in a workshop.
History of Go-Kart
Go-kart technology has been widely developed since the introduction of
wheels. But, it was not fully implemented in racing activity until the past
three hundred years in America. The first go-kart was simply a cart
from
handles
jointed
together
pushed
as
children
consisting of wheels and
behind when learning to walk or a four-wheeler platform where children
can sit on it while another push the kart around.
Go-kart was invented in California by Art Ingels and Lou Borelli
using 100cc mower engines
and strong steel frames. Then, newly
designed karts were beginning to gain popularity in Britain around the year
1959-, i960. Go-kart has long existed in our world whether used in sport or
recreation. By definition of International Karting Commission - Federation
International Automobile (CIK-FIA), a kart is defined as a land vehicle with
or without a bodywork, with 4 non-aligned wheels in contact with the
I
ground, two of which control the steering while the other two transmit the
power. Its main parts are the chassis (which consists of a body frame work
that is made up of a set of bent steel pipes that are welded together)
with
an engine, four wheels and tyres attached on it.
Figure 1.1 One of karting
pioneer, Don Boberick riding the
Xterminator
first
Rathmann
prototype kart. (Extracted from
http: //www. vintagekarts. com)
1.2 Don driving the
Figure
"Drone" at the Rose Bowl parking
(Extracted
1957.
from
lot
http: //www. vintagekarts. com)
1.2
Go-Kart Today and Future
Go-kart racing is a cheaper and smaller way of automobile racing not
forgetting, a lot safer compared to other motor racing sports such as
2
Formula One. Today,
go-kart racing is not only practiced
by adult hut the
Allowing an early start on this sport, as young as the
younger generation.
age of 5 or 6 years old. would he beneficial as it is the most suitable period
for them to gain experience
Practicing on go-karting
environment,
competitions
training
them
to be professional
go-karting
is as popular
the technology
in go-karting
One of the challenges
more standardized
racer
in various
as it has ever
been
with
who have stayed with
seems to be stabilizing
market.
at a stage
was done on the performance.
in improving
go-karting
would
be building
track for the growing number of go-kart's driver.
With continuous
techniques,
motor
are capable to stabilize and obtain a promising
even though minor improvement
designs,
in the future.
can properly expose the driver to the actual racing
growth every year, and the manufacturers
go-kart industries
However,
driver
such as Formula One, NASCAR, Indy racing, and others.
Nowadays,
continued
to be a professional
equipments,
improvement
services
in go-kart industry whether on go-kart
such
as
available
tracks,
or
driving
this sport would surely obtain a very high ranking of popularity
in the near future.
2
Literature Review
2.1
Introduction
Usualiy a go-kart driver or owner who wants to improve the handling of the
vehicle
will
equipment,
purchase
latest
in wheels,
tyres
and other
optional
but end up finding that those things in fact handles worse. The
first stage in achieving
percentage
the
a good handling kart that will provide the greatest
of power efficiency is to go right back to basics.
The chassis is the framework of any vehicle. The suspension,
steering, and drivetrain components (such as engine, transmission, and
final drive components) are mounted to the chassis. The chassis would
have to be strong
and rigid platform to support
the suspension
Automotive
Chase
Mitchell,
Jr.,
Halderman,
D.
D.
(James
components
Chassis Systems, 2000, p. 1). Furthermore, the constructions of today's
vehicles require the use of many different materials.
Chassis of a go-kart is not much different from a normal car
chassis, in fact, it is much less complicated. The different in size and
weight make go-kart chassis much easier to design and construct.
2.2
Chassis Design
A typical dictionary definition of chassis usually includes terms such as
framework on which the body or working parts of a vehicle, radio or
4
television are built (Oxford Advanced Learner's Dictionary, p. 190). There
are three basic designs used today: frame, unit-body, and space frame
construction.
2.2.1 Frame Construction
The frame construction usually consists of channel-shaped steel beams
welded and/or fastened together. The frame (chassis) of a vehicle will
supports all the `running gear' mounted on it, including the engine,
transmission,
rear axle assembly
(if rear-wheel
drive), and all the
suspension components.
The type of frame construction
that is referred to as full frame, is so
complete that most karts can usually be driven without the body.
Terms and label of different kind of frame are as follows:
Ladder Frame
This type of frame is common for the type of perimeter frame where the
transversely (lateral) connected members are straight across. Figure 2.1
show as a ladder frame sample where viewed with the body removed. The
frame resembled a ladder viewed from top.
Figure 2.1 Ladder frame of a common vehicle.
(Extracted from Automotive Chassis Systems, p. 2)
5
Perimeter Frame
This type of frame consists
the entire perimeter
of the body (Figure
provide support underneath
suspension
of welded or riveted frame members
2.2). The frame
around
members
the sides as well as for the suspension
will
and
components.
::
Figure 2.2 Perimeter frame of a common vehicle.
(Extracted from Automotive Chassis Systems, p.2)
Stub-Type Frame
Stub-type frame (Figure 2.3) is a partial frame often used on unit-body
vehicle, a type of vehicle construction, first used by the Budd Company of
Troy, Michigan, that does not use a separate frame. The body is built
strong enough to support the engine and the power train, as well as the
suspension and steering system. The outside body panels are part of the
structure
(James D. Halderman,
Chassis
Systems.
Chase D. Mitchell, Jr., Automotive
2000, p. 495)] to support
the power train and
suspension components. It is also called cradle.
6
I.
i
Figure 2.3 (a) Unitized construction, the small frame members are for
support of the engine and suspension components. Many vehicle would
attached the suspension components directly to the reinforced sections of
the body and do not required the rear frame section; (b) separate body
and frame construction. (Extracted from Automotive Chassis Systems, p. 2)
2.2.2 Unit-Body Construction
Unit-body construction (sometimes referred as unibody) is designed in
such a way that the body is combined with the structure of the frame. The
body itself supports the engine and driveline components, as well as the
7
suspension and steering components. The body is composed of many
individual stamped steel panels welded together.
The strength of this type of construction
The arrangement
assembly.
of parts to be jointed
vehicle
during
any
or formed
not only
high stress but also the stability of
provides sufficient strength to withstand
the
lines is in the shape of the
The
performances.
typical
vehicle
separate and different stamped steel panes that are spot-welded
uses
300
to form a
vehicle's body.
2.2.3 Space Frame Construction
Space frame construction
is a type of vehicle construction
that uses the
structure
of the body to support the engine and drivetrain
as well as the
steering
and suspension.
(James
D.
Systems,
framework
Halderman,
The outside
Chase
D.
body
Mitchell,
panels
Jr.,
are non-structural
Automotive
Chassis
2000, p. 494)] consists of formed sheet steel used to construct
a
for the entire vehicle. The vehicle using this type of framework
is drivable without the body. It would only uses plastic or steel panels to
cover the steel framework.
2.3
Platform
The platform of any vehicle is its basic size and shape. Various vehicles of
different makes can share with same platform and, therefore, many of the
same drivetrain and suspension and steering components.
8
A platform of a unit-body vehicle includes all major sheet-metal
components that form the load-bearing structure of the vehicle, which
include the front suspension and engine supporting sections. The area
separating the engine compartment from the passenger's seat is variously
called bulkhead. cowl panel, dash panel, or firewall. The height and
location of this bulkhead panel to a large degree determine the shape of
the rest of the vehicle.
Other components of vehicle platform design that affect handling
and ride are the track and wheelbase of the vehicle the track of a vehicle is
the distance between the wheels, as viewed from the front or rear. A widetrack vehicle is a vehicle with a wide wheel stance; this increases the
stability of the vehicle especially when cornering. The wheelbase of the
vehicle is the distance between the centre of the front wheel and the
Vehicle
long
from
the
the
with
a
side.
as
viewed
rear wheel,
centre of
wheelbase tends to ride smoother than vehicle with a short wheelbase
(James
D. Halderman,
Chase
D. Mitchell, Jr., Automotive
Chassis
Systems. 2000, p. 3).
2.4
Chassis Materials
Most of the automotive components and parts are made of cast iron, such
as brake drums and rotors, spindles, engine blocks, and many other
components including fasteners. There are different types of steel for each
component, which requires different strengths and characteristic from the
9
material. The amount of carbon in steel is the most important point in
determining the strength, hardness, and machining characteristics.
2.4.1 Galvanized Steel
Galvanized
from
steel is steel with zinc coating which could protect the steel
corrosion
zincrometal,
(rust).
Another
type
which is a two-coat
of rust-resistance
bake-on
system
steel
includes
using chromium
oxide
and zinc.
2.4.2 High-Strength
Steel
High-strength steel (HSS) has been introduced widely since the mid1970s, as many car and light truck parts have been built with it. Application
is
doors
high
the
in
the
HSS
is
strength
where
under
sill area
commonly
of
in
in
Other
lightweight
is
are
vehicles
applications
needed.
required, yet
the bumper supports and impact beams in doors.
HSS is very hard, but heating causes it to lose much of its strength.
High-strength steel is low-carbon alloy steel which consists of various
amounts
of carbon,
silicon,
phosphorus,
nitrogen,
and manganese
(Kalpakjian, Manufacturing Engineering and Technology, 1995, p. 166).
Body
repair
technicians
should
always
follow
manufacturers'
recommended procedures to avoid weakening the structure of the body.
1O
2.5.2 Length
Equalizing
both sides' dimensions
of the chassis length is very important.
It can be done by heating the front axle and twist the top of the king pin
with the greatest
lean back to a more upright position to match the other
side.
2.5.3 Steering Position Alignment
The next step would be aligning the steering position. Firstly, the rims of
the front wheels must be machined so that the inner and outer diameters
on both wheels are all exactly the same size. Then, it is possible to use a
straight edge to check the front wheel alignment.
Centralizing the steering should be done so as to have the kart
steering evenly in both directions, and tracking well in a straight line.
The steering shaft in most modern karts is offset to the brake side
of the kart. With the wheels fitted, it is necessary to find the difference from
the centre of the steering shaft at the steering yoke to the inside of each
front wheel level with the steering arm on the kingpin. This amount of
offset should then be built into the tie rods when the steering yoke is at
bottom dead center (idea quoted from http://akrweb. com/karting). Then,
the toe in and toe out desired can be adjusted by equa; ly lengthening or
shortening both tie rods. However, the straight edge should first being
placed across the machined wheels to check that both are set on the
same amount of camber before setting the toe in. Front wheel alignment
should only be done if the camber is equal and at the desired angle.
12
2.5.4
Kart Straightness
The kart should be check if it is twisted. With the kart positioned on a flat
floor,
place the wheels
correctly
inflated,
then
and tyres back on the kart and with the tyres
using
a set of scales
lift each front wheel
by
hooking the scale hook around the king pin. Then spin the wheel lifted and
slowly lower the kart until the wheel touches the floor and note the amount
of lift needed at the point of contact. Each side of the kart should require
the same amount of lift. If this is not the case, the chassis is twisted. To
correct the situation,
place the rear wheel on the same side, as the kart is
light at the front and with someone
standing on the opposite rear wheel
twist the light front side of the kart down. This should be repeated until the
both front wheels carry the same amount of weight. Once the front is even
the back will also be even (idea quoted from http: //arkweb. com/karting).
The rear axle should be check if it is located central to the chassis.
Firstly, try centering off the chassis tubes and then checking the axle
diagonally with the tops of the king pins to check if the chassis runs out of
line in the centre. If fault was found with the diagonal check in the chassis,
it is best simply offset the axle slightly. Once this is done, the ends of the
rear axle can be used accurately for setting the position of the rear hubs.
2.5.5 Other Jobs
With all the previous 4 jobs done, some other minor activities should then
be carried out. First clean and oil every bearing and moving the chassis
where necessary by removing it from the chassis. Make sure each moving
13
part is in good condition or otherwise,
all king pin bearings,
and axle bearings
replace it if doubtful. Make sure that
steering shaft bearings, tie rod ends, wheel bearings
have a good fit and not sloppy. Finally, check the kart
for any cracks and repair where necessary
before putting everything
back
together.
Once all the steps have been completed, think about setting up for
a particular class to help setting the engine requirement.
2.6
Basic Go-kart's Chassis Theories
'lt is the responsibility of each karter to determine his own requirements. It
is also the karters responsibility to stay within the sprit and intent of the
Martin,
be
'(Brian
he
in
the
participating.
of
organization
which
will
rules
Go-kart Racing- Chassis Setup, 2000)
Setting up a good go-kart chassis requires not only the knowledge of basic
theories
but also from past experiences.
setting their first go-kart
but experiences
Theories
would
will help beginners
help further
improve
in
it.
Some of the chassis theories will be discuss in the following section.
2.6.1 Frame Construction
The most important aspect in the frame of a go-kart would be its flexibility,
as it is most crucial during cornering in a race. The flexibility of the frame
can be achieved either by using a particular type of material such as
Chrome-moly, or perhaps just by proper design.
14
Some flexibility is good for a go-kart and even makes setting up
easier, but over the time the frame may not rebound back to its original
condition. According to most chassis builder, current frames in the market
are only good for about 18 months before replacement is needed. Racing
on the same track week after week would cause the frame to take a set,
which diminishes its flexibility. One of the easiest ways to alleviate this
condition is by running several laps in a backward direction on the same
track.
2.6.2 Side Bite
Site bite is the ability of the go-kart
to stay stuck on the track without
sliding when going around a corner. With the correct amount of side bite,
the go-kart would unload the inside rear tyre when taking a corner which
will reduce the effect of scrubbing
would
cause
a hop or bicycle
the tyres. However, too much side bite
around the corner or scrub off so much
speed causing the engine will bog down. On the other hand, too little side
bite will cause the kart to be loose.
The design of the go-kart frame itself has a lot to do with how much
One
it
has.
bite
good indication is by measuring the width of the rear
side
frame rails. A narrow kart would measure 24" to 25" while a wider kart has
27" to 28", measured at the center of the frame rails
Side bite is also affected by frame stiffness. The frame is essentially
a series of torsions bars welded together. The shorter the bars and the
more triangulation, the stiffer the frame will be. The frames flexibility can
15