Cobra Engineering
Striving to achieve accuracy and precision in a timely fashion
Tender Submission to Archibald Engineering vehicle
design
Cobra Engineering Contractors




Scott Press
Tim Harrison
Nirav Khant
Maung Ko Thant
Cobra Engineering
striving to achieve accuracy and precision in a
timely fashion
Tender Report
This document is recognised as an official transcript from Cobra Engineering to Archibald
Engineering. It is an application put forward by Cobra Engineering to Archibald Engineering in
response to the construction of Archibald Engineering ‘Mouse-Trap Car’ design.
Essential Criteria
Time Management
We at Cobra Engineering believe that ‘Time is Money’. Every professional decision has to be
followed promptly by action and within the time constraint provided. If this is not done, it leads
to delayed production, unsatisfied clients and an overall increase in cost. Therefore, the team at
Cobra Engineering have developed a timeline for the construction of the Mouse Trap Car that
with approval from Archibald Engineering will be handed over on the 29th of September 2009.
Construction Time Line
Monday 7/9/09
Tender Document submitted to Archibald
Engineering
Monday 14/9/09
Approval of Tender by Archibald Engineering
Tuesday 15/9/09
Commencement of Construction of Mouse Trap
Car
Friday 18/9/09
Progress report sent to Archibald Engineering
stating all events, mishaps, concerns, and
alterations related to the construction of the
Mouse Trap car
Tuesday 22/9/09
First testing of the Vehicle- team members from
Archibald Engineering will be present.
Friday 25/9/09
2nd Progress report sent to Archibald Engineering
stating all events, mishaps, concerns, and
alterations related to the construction of the
Mouse Trap car
Tuesday 29/9/09
Second testing of the Vehicle- team members from
Archibald Engineering will be present. Mouse Trap
Car handed over to Archibald Engineering.
Tuesday 13/10/09
Vehicle assessment
Communication
Cobra Engineering believes that good communication is vital in the process of design and
production. If the communication between two professional companies goes wrong, drastic
and unwanted results may be produced which also lead to an increase in cost and waste of time.
Therefore, Cobra Engineering will optimise its decisions and actions by maintaining firm contact
with Archibald Engineering, both verbal and electronic, to ensure that the requirements of
Archibald Engineering are always met.
Rhys Jones has been appointed as the company secretary for Cobra Engineering. His primary
role is to maintain and update the company website, check company e-mails at least once daily
and to reply to all e-mails within 24 to a maximum of 48 hours of receiving them. In addition to
this, contact information of all members of Cobra Engineering can be found on our web site
cobraeng.viviti.com where you will find profile photos, personal e-mails and contact phone
numbers.
We also will provide progress reports on the 18th and 25th of September 2009 as shown in the
timeline that clearly state all events, mishaps, concerns, and alterations related to the
construction of the mousetrap vehicle. Moreover, they will include positive and negative
feedback experienced along the way regarding the construction.
Finally, any discrepancies or questions about specifications or drawings will be immediately
forwarded to the designers of Archibald Engineering.
Cost of Production
In any professional organisation, one of the main aims is to keep the cost of production as low
as possible. We at Cobra Eng. strive to do this. As the requirement of Archibald Eng. states that
the overall cost should not exceed $40, Cobra Eng. can guarantee that as we are in constant
contact with several suppliers and will purchase the required materials whilst still maintaining
the high quality state or version of the material from the best of the competitive prices we
assess.
Cobra Eng. has a team that constantly updates its access to cheap and high quality materials
required for production. We will ensure that Archibald Eng. receive the best of prices for the
materials used.
Modifications and/or Replacements
As construction continues to progress, it may become evident that a specific material or aspect
of the design can be improved. Cobra Eng. will suggest possible modifications in the design or
materials in order to greater meet the specifications of Mousetrap Racing as Archibald Eng.
expects. This is vital as it will produce a better product in the end and greater satisfaction.
Cobra Eng. will always provide personal and professional opinions with justification to the
feedback from Archibald Eng. We will also find alternative lightweight options for materials
described in the specifications from Archibald Eng. ensuring always that the specifications
provided by Mousetrap Racing are not compromised.
Modification Process Stages
1. Request sent for change of design or change of construction method to Archibald
Engineering
2. If Archibald Eng. do not reply within 2 working days, another request will be sent
3. Archibald Eng. is to assess the request and a meeting is to be organised.
4. Changes agreed between both companies, documented and implemented on the
vehicle.
Desirable Criteria
Technical Expertise
At Cobra Eng. the technical team has a broad range of technical expertise amongst the team
members. Scott Press as general manager is very efficient and accurate in the delivery of
projects. In his previous project he designed and created an implementation plan for an
improved sanitation and waste water disposal system in the province of Kandal in Cambodia,
which received a credit from the ‘Engineers Without Boarders’ competition. Although Scott was
not involved in the construction he gained experience in the areas of time management, design,
and team communication which are vital in the delivery of a project.
Tim Harrison is the team construction supervisor, Tim also being a fully licensed electrical
contractor and working as an electrician for 10 years has extensive skills in construction
processes, design and plan interpretation and liaising with designers.
Nirav Khant is the team constructor and project manager, his expertise are in the area of
physics and mechanical systems.
The construction team at Cobra Engineering can guarantee that the design material outlined
will be acquired and the assembly procedure set out by Archibald Engineering will be adhered
to with a high level of accuracy.
Attitude
Attitude is a characteristic that determines how focused you are and at Cobra Eng. we always
have a positive attitude to face our daily engineering challenges. We believe in having a strong
relationship with the customer as well as being professional. This allows a certain comfort
between both parties in terms of communication and meetings.
We always look forward to challenges and the expectations that Archibald Eng. have will
certainly not be let down. A good work ethic and strong motivation amongst our team
members will create the best performing and most competitive mousetrap vehicle.
Experience and Handling
Cobra Eng. has a very wide experience in the field of construction. Our team members have
been involved in the construction processes of several projects before. For Example

Nirav Khant- constructed bore hole systems in Kenya that filter out arsenic from the
ground water. It was equipment that needed a high level of care during construction. He
has also been involved in several other construction projects.
Scott Press- he designed and created an implementation plan for an improved
sanitation and waste water disposal system in the province of Kandal in Cambodia. This
too requires a high level of accuracy and care during construction and Scott has gained a
lot of experience from this.
These are just a few to mention. We at Cobra Eng. guarantee the full care and strict handling
during construction to ensure a satisfying and expected finished product.
Construction Method
Construction is to be carried out as accurately as possible to achieve the best outcome for the
desired product. Cobra Eng. will follow the steps of construction as accurately as possible
ensuring the use of logical steps, with detail and adherence to diagrams and specifications of
the designers of Archibald Eng. as well as the best environment and work space for the
construction process.
We also have wide knowledge in the field of automotive engineering. Cobra Eng. has
demonstrated sound knowledge in mechanical concepts such as fluid mechanics, distribution of
forces in gear systems and many others. We therefore ensure that we will produce a car with
good understanding on how recharge the string, including the method of rotation as the
designers of Archibald expect.
Competency
Cobra Eng. Recognise the fact that the ability to follow instructions, understand diagrams and
communicate with a very high level in English is vital to any engineering firm. We have done
this in the past and we will always adhere to our principles in maintaining a high level of
competency in this regard.
We at Cobra Eng. also understand that in constructing a vehicle, there are various processes
that need to be followed in which some require the understanding of complex shapes and parts
of the design. We therefore have appointed Thomas Murphy as the chief engineer and William
Aung as the design analyser. Thomas has over 10 years of experience in the field of Mechanics
and has worked in various industries before. The latter has wide knowledge in the field of 3D
designs and has experience in the analysis of 3D designs. With this in mind, we at Cobra
guarantee that we are competent enough to fully understand the complex shapes and parts of
the design in order to produce it.
Resources
Firstly, Cobra engineering recognises the importance of sustainability in modern engineering,
and will take steps to ensure the use of environmentally friendly material and to minimise
wastage through precision craftsmanship and advanced planning procedures.
Last but not least, Cobra Eng. has access to a wide range of equipment required for the
production of the mouse-trap car. We have produced many products in the past and with
support from our advanced transport network, we are able to access any additional equipment
required in a very short time.
We at Cobra Engineering Eagerly await your reply.
With kind regards
The construction team
Cobra Engineering
APPENDICIES
Drawings and Specifications as outlined by
Archibald Engineering
Materials List
Description
Cable Ties
Compact Disc – CD
Quantity
2
2
Weight (g)
15g x 2
Cost ($)
*
*
Elastic Band
100mm Diameter
Elastic Band
60mm Diameter
Mini Compact Disc
2
30g
-
0.5
2
-
0.5
2
7.5g x 2
0.5
Rubber Washers
Explained below
4
15g
2g x 4
0.5
Skateboard Ball Bearings
22mm x 7mm
8mm Diameter hole
Brass Axle
8mm Diameter x 120mm Long
4
8g
73.9g x 4
20
2
295.6g
52.6g x 2
4
Nylon Cord
Chicken wire
Epoxy Glue
Rubber
200mm
50mm
100mm x 100mm x
10mm
1 roll
1 can
105.2g
-
2
*
*
3
64g
*
*
5
4
50g
517.8g
Free
40
Masking Tape
WD40
Graphite Powder
Balsa Wood
190mm x 70mm x
30mm
1
Mousetrap
TOTALS
*Note- Objects with the asterisk were deemed to be readily available at a negligible cost
Rubber Washers
The rubber washers are used to fill the space between the hole in the CD wheels and the axle. They
need to have an external diameter of 15mm and an internal diameter of 8mm. Diagram shown below.
Tools
Sandpaper- Used for smoothing rough edges
Ruler – Measuring Dimensions
Small Knife or Stanley knife-Cutting balsa wood
Miniature Hack Saw- Cutting Balsa Wood
Compass- In order to make hole for ball bearings
Pencil- Markings for cuts and holes
WD-40- Used to lubricate the bearings
Cloth- Remove excess grime
Method and Fixing
Total Build Time = 85 minutes
Building the body- 15mins
The balsa wood can be shaped in two ways. If a block (200×100×50mm) can be purchased, the body can
be shaped to fit the required mould. If the thickness of 50mm cannot be purchased, then a number of
sheets must be fixed together to give a thickness of 50mm before the body can be shaped.
As the balsa wood is very easy to work. The shaping can be completed using a small knife or Stanley
knife. Firstly, mark the design using a pencil and ruler, once the markings are complete and correct,
proceed to cut body.
Putting in the ball Bearings – 20 mins
Mark a dot with a pencil 20mm in from the back end of the vehicle, and 15mm straight up. From this
dot and using your compass inscribe a circle 22mm in diameter.
*Note before starting this step remember to make sure the hole is not too big as the ball bearings
need to be squeezed in tightly into the body in order to stay in place.
Using your small knife cut around the inside of the line, then use the sand paper to smooth the inside.
Give the bearings a good clean with some WD-40 and then rub with a clean cloth. Now cover the inside
of the circle in the body with a thin coating of Epoxy Glue. The next step is to place the ball bearings in
the hole you have just made, ensuring they fit snugly and the glue will hold them in place. Remove
excess glue with the cloth.
Mounting the Engine-10 mins
The first step here is to trace where the mousetrap will go using a pencil and ruler, refer to the diagram
below.
Next, place a thin layer of epoxy glue within the tracing you have just made, ensuring good coverage.
Now situate the mousetrap on top of the glue ensuring it is the right way around (the lever arm needs to
be able to swing to the front of the car). Once the mousetrap is in position, use three evenly spaced
cable table ties to fasten it to the body (see image below).
Cable ties in red,
remember that the ties
go around the
mousetrap and body
Attaching the Nylon Cord- 5 mins
First cut a piece of nylon cord 20cm long (This distance includes the knot length). To attach the
cord, tie a knot around the middle of the mousetrap arm. Now pull the lever arm back and rest
it beneath the hold down bar to keep it in place. Now create a small loop in the other end of
cord and place this loosely around the small catch located on the back axle.
Note: This photo is not our
mousetrap car but gives an overview
of how to connect the string to the
axle
Remembering that this should not be too tight as it has to come off easily when the car uses
up the strings length.
Wind the string around the big gear, one rotation will be sufficient then you can spin the wheels
in reverse to put the string on. Put approximately half of the string length on the big gear and
half on the axle to the right side of the gear (if you are looking from the back of the vehicle). Do
not wind the string loosely or it will snag itself and be careful not push on the mousetrap's lever
arm during this process, you want the string to be tight and to pull the lever arm over.
Note: This photo is not our
mousetrap car but gives an overview
of how to wind the string to the axle
Simply raise the jaws of the trap slightly and take the looped end of the string and place it over the wire
that was attached to the rear axle. Reverse the car to allow the string to wind around the axle and pull
open the jaws of the trap. Release the car on the ground and it will speed away.
String Release Mechanism – 15 mins
The string release mechanism can be made out of standard chicken wire, which can be purchased at any
hardware store. It can be worked into the shape required using hands
Rubber Supports – 10mins
1. Cut the rubber block into 4 even blocks of dimensions 50mm x 50mm x 10mm.
2. Take two of the blocks and cut them down to 35mm x 35mm x 10mm blocks.
3. For each block drill an 8mm hole through the centre of the 50mm x 50mm or 35mm x 35mm
face.
Attaching the Wheels –
20min
FRONT
1. Before
assembling
the wheels and axle ensure the
axle fits through the
hole in the ball bearings. If the
axle does not fit lightly sand back until it does.
2. Insert rubber washers into the holes of two mini-CD’s, ensuring that both have a snug fit. Stretch
the 60mm elastic band over the external circumference of the wheel for tread.
3. Push a rubber support onto the axle making sure to leave room for the wheel to fit on.
4. Push the brass axle into the hole in the washer of one wheel, also ensuring that it has a snug fit.
5. Put some epoxy glue on the inner side of the rubber support and press against the wheel. The
wheel should grip the axle. The axle should stick out one side of the wheel by approximately
2mm and should be at 90 degrees to the axle.
6. Insert the long end of the axle through both ball bearings on the front of the vehicle.
7. Repeat steps 3 – 5 to attach the second wheel with rubber support.
BACK
1. For the rear wheels follow the instructions for the front wheels instead use standard sized CD’s
instead of mini CD’s and using the 100mm elastic bands instead of the 60mm elastic bands.
Making the Gear and string release– 5mins
1. Mould the chicken wire into the fish hook shape design shown in the diagrams, once the mold is
in the desired shape, loosely attach it to the axle.
2. The gear is made by attaching the end of the masking tape to the rear axle with the centre of
the masking tape 10mm to the right of the centre of the axle.
3. The axle is then rotated until the masking tape builds up to a diameter of 16mm. it is important
to make sure the end of the string release mechanism is under the masking tape around the
axle, and the other end of the string release is fixed to the axle with one layer of masking tape.