Group 4 - Product Name Here
TRAXXAS R/C NITRO TRUCK
The purpose of Gate 1 is to effectively plan out the time-line of the project.Sections in this gate include:
- Work Proposal
- Management Proposal
- Initial assessment and archaeology of product
Purpose: To provide an outline of how we plan to reverse engineer our product. This includes how we plan to disassemble and later re-assemble our product. Secondly, the purpose of the work proposal is to identify the capabilities our group has concerning the project and the shortcomings it may have or experience in regards to the project during semester.
Disassembling will be done in sections based on the subsystems of the product. Each subsystem will be disassembled and analyzed separately one at a time in order to keep the system components organized. After a system has been completely dissasembled and analyzed it will be reassembled and set aside. At that time the disassembly of the next subsystem can begin. Listed below are the subsystems present with specific details on the disassembly approach for the system.
Listing of subsystems:
- Engine/Transmission- This is the most complex of the subsystems and will take the longest to disassemble and analyze then reassemble. We are expecting dissasembly to take about one hour and reassembly to take about two hours. We do not expect any challenges to present themselves in this subsystem.
- Braking system- The brake system will be removed during the engine/transmission disassembly because it is connected to the transmission. Further disassembly will be done on the brake as a system separatly and should take approximatly fifteen minutes to disassemble and twenty minutes to reassemble. We do not expect any challenges with this system.
- Suspension system- The suspension system has a large number of components and will take about 1 hour to disassemble and 1.5 hours to reassemble. Although there are more components than the engine system, the interactions between the components are simpler and will make disassembly easier.We do not expect any challenges with this system.
- Steering system- The steering system is very simple and only has a few components. This system will be removed during the suspension disassembly but will be disassembled separatly. Disassembly time predicted at twenty minutes and thirty minutes to reassemble. We do not expect any challenges with this system.
Tools that may be used:-
- (5) Nut Drivers: 4, 5, 5.5, 7, & 8mm
- (6) Hex Drivers: 1.5, 2, 2.5, 3, 3.5 & 4mm
- (3) Phillips Screwdrivers: 0, 00 & 1
- (3) Flathead Screwdrivers: 2, 3 & 4
- (2) Box Wrenches: 5 & 8mm
- (1) Ratcheting Handle
|Group Member||Positive Attributes/Capabilities||Negative Attributes/Shortcomings|
- Experience at Toyota as an estimator
- Extensive mechanical background
- course balancing/ time management
- Skilled in Technical Writing
- No work experience
- Good communication skills
- No hands-on experience
The group meetings are held on Mondays, Wednesdays and Fridays at 8 pm in the Capen library. In case one member is not able to make it, after the meeting with the rest of the members, the left out member will be emailed his portion of the work to be done. In case he/she has any doubts, it will be clarified over the phone or over emails to all the group members. These meetings are held for about two or three hours and each group member will be assigned an even amount of work to be researched upon and completed and emailed to each other’s accounts . Then in the proceeding meetings, together with the team, materials will be compiled and edited. Steve who is well versed in the English language will have a final look at the whole project and will give the final confirmation. However, if the Project is due in the evening, the group is required to meet the same morning to finalize the project. These meetings enable us to gradually build up the final output by combining all the data that is gathered. It helps us to build a time table and become more systematic in our work. In addition, it also helps us to add/edit more ideas and views. It also keeps us from leaving all the work for the last minute. These meetings can also help us to develop professional skills like expressiveness of views and ideas, systematic way of thinking and professionalism as a whole that will surely help us in the future.
Timeline of Project
Group Member Roles
Wren Jacob (Project manager)
Wren Jacob will be responsible for suggesting a fair amount of work for each group member and also setting up meetings and informing everyone about the timings of where and when everyone should meet. He will be in charge of how the project is executed so that the end result is successful. Schedules and tracking must flow. He prepares steps and makes needed changes if a problem or delay occurs.
Steve Cevaer (Technical Director )
Steve Cevaer is responsible for Technical Operations of the product or performance. Operates, maintains and safeguards the technical assets of the product which is the Traxxas RC truck, including supervising, communication, and the use and maintenance of stage facilities. He also: Determines the necessary Technical Applications required for the dissection and the assembly of the product. He also advises the project manager, editor and the communication guy on the technical specifications, costs and usage of technical equipment required for the dissection and reassembly of the product.
Mohammed Siddiqui (Communication Liaison/Co-editor)
Mohammed Siddiqui is responsible for maintaining a good relationship with the group members, professors and teaching assistants. He will also be the point of contact and will inform the rest of the group about what the information shared from the professors and TA’s. He will also review the team agenda and hold emergency meetings outside the scheduled meeting timings and days. Furthermore, he also shares responsibility of editing this page with the Editor.
Muhammad Firdaus Samsudin (Editor)
Firdaus Samsudin is responsible to: Prepare, rewrite and edit copy to improve readability, or supervise others who do this work. Read copy or proof to detect and correct errors in spelling, punctuation, and syntax. Allocate print space for story text, photos, and illustrations according to space parameters and copy significance, using knowledge of layout principles. Plan the contents of the work and mentioning the references
In the event of a conflict within the group, the group will schedule a meeting to resolve the conflict.
Resolution procedure follows:
1. Hold a meeting during a time every member is available.
2. Discuss the conflict including supporting reasoning for each side’s argument.
3. Vote on the solutions to the conflict.
4. Majority vote wins. If there is a tie, we will decide by a coin toss.
PRODUCT ARCHAEOLOGY: Preparation and Initial Assessment
Product Development Profile
The Traxxas Nitro Sport that we are studying was manufactured in 2006. It is a revised version of the previous model that was first introduced in 1996. Their targeted market sales are the United States. However, consumers from other countries can still purchase this product through Traxxas website. This remote control (RC) car was intended for the use of an adult, children could operate this toy with the supervision of a responsible adult. The RC car can give the consumer a sense of controlling 1/10 size of a real car with their bear hands using remote control. It can be operated up to 38 mph. A sense of enjoyment and satisfaction can be felt while operating this toy. In addition, the styling of the car might give an inspiration to artists who saw this car. At the time of product development, there is a global concern about the product. Even though it is available online for everyone to buy, it wasn’t intended to sell in non-English speaking countries. This is because the instruction manual of the product was written in one language, which is English. Economically, the main concern was the price for the RC car, is it affordable?
Product Usage Profile
The Traxxas - Nitro Sport (#4510) product is used as a toy for boys and girls around the age group of 12-26. They improvise the real cars and perform/ conduct races and stunts with it. These trucks are mainly intended for people who are interested in cars and racing. There are people who race with these nitro sport trucks. Sometimes these trucks can hold cameras and be used to spy on people or places like in the movie ‘Fast Five’. It runs through different types of terrains at high speeds up to 38 mph. This product is mainly used inside homes or outside like in the yards or fields to perform races or stunts. They produce high volume of sounds which might not be pleasing to the ears if played with inside the house and also it has a possibility of damaging things in the house or perhaps injury to small kids if there are any present in the house. It is used for recreational purposes and also for getting a feel of the intense speed involved through the rough terrains it runs through. The Traxxas Nitro truck is a source of entertainment for boys and girls who are interested in cars and racing. These products are able to even drag the baby strollers in a safe manner in some cases as was seen in one of the videos in YouTube website. They are sometimes fitted with camcorders and taken around just to get an overview of the surrounding or to spy on people or places like the movie ‘Fast Five’.
RC car burn nitro(gasoline like-fuel), which is made up of the combination of methanol, nitro methane and lubricant oil. The nitro fuel will go inside the fuel tank and into the nitro engine in which it will enter the combustion chamber to mix with air. The glow plug is what initiates the combustion process. The combustion of fuel and air pushes the piston downwards and gases start to clear out of the exhaust cylinder. After the emission of the gases, the intake port begins to open and let the fuel or air in. This process produces combustion and the whole step is repeated. The combustion of fuel is what makes the engine running and causing the car to move. Nitro fuel is a chemical energy, which later on will convert into thermal energy in the combustion chamber, and eventually mechanical energy that makes the car moves.
Product Complexity profile
There are approximately fifty components used in each of the subsystems of the car with each consisting of a few parts. The way we have defined component suggests that as an example, the shock absorber and spring are a component of the car and the spring and other shock parts are considered parts of that component. The components of the steering and suspension systems do not appear to be very because the connection to hold them together are easy to handel based on observation. However the components included in the power transmission sub system seem rather complex based simply on their required tasks. For instance the transmission’s duty to transfer the rotational energy from the engine to the rear wheels would probably require some type of gear reduction system that would include components we can see on initial assessment. The interaction between components in the engine and transmission are very complex as engine burns fuel to move the piston that is directly connected to the transmission. Simple interaction between transmission and rear tire is establish after the mechanical energy is transferred from the engine through the transmission.
Product Material Profile
The materials clearly visible on our product are as follows:
• Plastic- Used for chassis and body components.
• Aluminum- Used on the Engine block and exhaust.
• Steel- Used for fasteners, springs, steering parts, and drive parts.
• Rubber- Used for tires and fuel lines.
Most of the components and their parts are visible and based on previous questions in this section we think that the materials listed above are all the materials present on the product.
User Interaction Profile of Product
The user interface for the product is a remote controller. The controller consists of a small (approx. 3in diameter) steering wheel and a finger trigger. The steering wheel is a very intuitive control device that allows the user to steer the car. This may however not be intuitive for someone who has not driven anything before and doesn’t understand the steering concept and may take some time to learn. The finger trigger is the throttle/brake control and after a few seconds of operating the car, the throttle control becomes very natural to the user. The controls are easy to use but the driving of the car is somewhat difficult to new users. The difficulty with operating the car is that the car is very fast and without a steady hand on the steering control the car will react quicker than expected to the user’s steering inputs, possibly crashing the car. Also the concept of steering while driving towards yourself takes practice because for the car to go to your right you must turn it to its left and vice versa.
Maintenance is limited to replacing parts that have become damaged by rough use. All of the components are available through Traxxis and other companies and hobby shops and can easily be installed by the user with minimal tools and limited mechanical background.
Product Alternative profile
An electric radio control truck could be used instead of a nitro powered truck. The electric is as fast as the nitro. It gets up to 70 mph. It has an electric start which turns over the motor and also lights up the glow plug. It has the same components such as the oil shocks, independent suspension, electric speed controller and a differential. The advantages of an electric remote control car is that it is found at a variety of places for sale. It runs on brushless motors which makes it more faster . It is clean and efficient. There is no trouble involved in starting or tuning the engines nor are there any troubles about the ignitions and glow plugs. It is simple and easy to use especially for beginners and is cheaper. Electric trucks just need their batteries charged. It has great acceleration and gets up to the top speed upon the pull of its trigger which is up to 70 mph. It requires less maintenance. It is mainly intended for beginners or for people who don’t have much time to spend on maintenance. After the battery power is low then the fun for that particular day is done unless there is another spare battery available instantly to replace. After the battery is depleted the the truck cannot perform or run or race and thus needs a lot of time to charge the battery to get back in action again. The electric powered trucks are usually preferred over the nitro ones because it uses less time and effort for maintenance compared to nitro powered trucks. The electric powered trucks are more clean and efficient compared to the nitro because they do not require as much as maintenance. It is more simple to use and cheaper in cost prices because of the maintenance and the cost of the fuel change every time it runs out of gas. The electric powered truck has a speed of 70 mph which gets to its top speed upon the pull of the trigger unlike the nitro powered truck which gets a max of 40 mph and doesn't get pumped up to full speed immediately. The electric requires less maintenance because it has less internal parts such as the receiver antenna, the belt which makes it move and the battery unlike the nitro powered which requires more maintenance and thus the cost of maintaining the nitro truck is more than the electric. The cost of the electric or nitro powered trucks vary from 50$ to 2000$. A very decent and appropriate truck will come up to 300 $. The electric trucks cost comparatively less compared to the nitro powered because there is less maintenance involved.
The purpose of gate 2 is to physically dissect the product. This includes:
- Preliminary Project Review
- Product Dissection
- Documenting the connection of subsystem
Preliminary Project Review
All members in-group four so far has followed the time line effectively and we were able to communicate in an appropriate manner in a way that everyone did their designated work. Each and every group member was present at the meetings that were held thus completing the gate on time. The disassembly process went exactly as planned except for a few minor difficulties. Each subsystem were dissected and analyzed separately with few minor problems.
The first problem was the removal of the front suspension from the chassis. The allen screws that held the frame of the suspension and the chassis was hard to reach by the allen wrench. All members decided that we need to slightly bend the frame in order to fit the allen wrench. We knew the risk of breaking the frame, however everyone agreed to the situation and were finally able to separate the chassis and the frame of the suspension.
The second problem we faced was the removal of the size 10 bolt from the inner drive shaft that was connected to the piston. There is approximately a 1.5 inch drive shaft coming out from the bolt. The length of the nut driver that we used to remove the bolt apparently was too short and we could not fully insert the nut driver into the bolt. The bolt was not only difficult to reach, also it was screwed very tightly to the inner drive shaft. One group member removed it eventually, but it took quite sometime because we had to push the nut driver into the drive shaft until it reached the bolt. It took two-group member to actually loosen up the grip of the bolt.
Motive of Dissassembly All the parts of the rc car are intended to be dissected because each and every part are available online for sale. Most of the parts are connected with each other with screws, nuts, bolts and washers, which can be removed manually.
- http://www.amainhobbies.com/index.php/cPath/1_25/n/RC-Cars-Trucks-Parts?source=google_general_terms&gclid=CPbF4pvukawCFYHe4Aodlwl-nw” *
|1||Remove the front wheels from the car by removing the 8mm lock-nut located at the center of each of the wheels.||8mm nut driver||2|
|2||Disconnect the front right and left tie rods from their corresponding spindles by removing the Phillips head screw located at the outer ends of each rod. There is one outer screw per side.||#2 Phillips Screwdriver||3|
|3||Remove the steering pitman arm from the steering servo by removing the Phillips head screw located in the center of the round control arm. The screw has to be accessed through the access hole in the bottom of the chassis. Once the screw is removed, the pitman arm can be simply pulled off the steering servo spline by hand.||#2 Phillips||2|
|4||Remove the steering servo from the chassis by removing the 4 socket head cap screws that hold it in place. They can be accessed from the top of the car. There is a slight complication in this step due to the angle in which the front screws must be accessed. The use of a ball-end Allen wrench will resolve this. Finally unplug the servo’s wire from the receiver. The receiver is located just behind the steering servo.||2.5mm Allen wrench||5|
|5||Remove the front left and right spindles by first removing the snap rings from the ends of the pin that holds each spindle in place. Once the snap rings are removed, the pins can be pulled out using a pair of needle-nose pliers. This is the final step for the steering subsystem disassembly.||Snap ring Pliers-Needle nose||6|
|1||Remove the entire front suspension assembly from the chassis by removing the 5 flat head Phillips screws as shown in the picture to the right.||#2 Phillips screwdriver||4|
|2||Remove the front 2 shock absorbers by removing the 4 Phillips head mounting screws located at each end of each shock absorber. After the screws have been removed, the shock absorbers can be separated from the front suspension assembly.||#2 Phillips||2|
|3||Remove the left and right upper control arms from the front suspension assembly. To do this you must remove the Phillips head mounting screws located at each end of each control arm.||#2 Phillips||2|
|4||Separate the left and right lower control arms from the front suspension assembly. To remove them the Phillips head screws pointed to in the picture to the right must be removed. There is 4 screws total to remove both left and right control arms.||#2 Phillips||2|
|5||Separate the car body front mounting bracket from the front shock tower by removing the 2 Phillips head screws pointed to in the picture to the right.||#2 Phillips||2|
|6||Separate the front shock tower from the front suspension assembly main frame. These are the final two components to the front suspension assembly. They can be separated by removing the 2 Phillips head screws.||#2 Phillips||2|
|1||Remove the rear wheels from the car by removing the 7mm lock-nut located in the center of each of the wheels. 7mm nut driver 1||7mm Nut-Driver||1|
|2||Remove the upper control arms from the rear suspension assembly by removing the Phillips head mounting screws from each end of each control arm. There is some difficulty in removing one of the screws because of the screw driver contacting the surroundings. The screw driver still has enough engagement in the screw to remove it, but it must be done with care not to damage the screw.||#2 Phillips||4|
|3||Remove the battery cover and the battery pack from the car by removing the spring clips located on each side of the battery cover, either by hand or by using a pair of needle nose pliers.||Hands||2|
|4||Remove the rear shock tower from the chassis by removing the 4 Phillips head mounting screws as shown.||#2 Phillips||1|
|5||Separate the left and right drive shafts front there corresponding axle carriers. First pull the black plastic hex shaped piece off of each axle shaft by hand. Then pull the metal pin from the axle shaft using a pair of pliers. After the pin and hex piece are removed from each side the axle can simply be pushed through the axle carrier.||Pliers||2|
|6||Disconnect the lower control arms and their hinge from the chassis by removing the two flat head Phillips screws in each hinge on the bottom of the chassis.||#2 Phillips||2|
|7||Remove the shock absorbers from the rear suspension assembly by removing the Phillips head mounting screws that connect each shock to the shock tower and the lower control arms. There are 4 screws total to remove both shock absorbers.||#2 Phillips screwdriver||2|
|8||Remove the axle bearing carriers by removing the Phillips head screws that connect them to the upper and lower control arms. There are 4 screws total to remove both left and right rear axle carriers.||#2 Phillips||2|
|9||Separate the lower control arm and its hinge by removing the snap ring on the hinge pin and pulling the in out using needle nose pliers. Do this for both left and right control arms. This is the final step in disassembling the rear suspension assembly.||Snap ring pliers, Needle-nose pliers||5|
|1||Remove the throttle/brake control arm from the throttle servo by removing the Phillips head screw located in the center of rotation of the controlling arm. Then the arm can be pulled off the servo spline by hand. Once the arm is off, the linkages must be disconnected. The brake linkage is disconnected by loosening the set screw and pulling the collar off. The throttle linkage is removed by rotating the linkage so the step in the rod comes out of the hole in the carburetor.||#1 Phillips,1.5mm Allen Wrench||6|
|2||Remove the throttle servo by removing the 4 Phillips head screws that hold it to the chassis. Then unplug the servo wire from the receiver.||#2 Phillips screw driver||3|
|3||Remove the muffler. To do this you must remove the Phillips head screw that mounts the front exhaust hanger to the chassis. Then cut the wire ties that seal the middle exhaust joint so the muffler and connection tube can be pulled off. Also the pressure line to the fuel tank must be removed by hand.||#2 wire cutters||4|
|4||Remove the electric starter by removing the 3 Phillips head screws that connect in to the engine block. Once the screws are removed the starter just slides off the end of the crankshaft.||#1 Phillips||2|
|5||Remove the screws from the bottom of the chassis that connect the engine mounts to the car chassis. Disconnect the fuel line by pulling the hose off by hand. Then the engine can be removed from the chassis for further disassembly.||#2 Phillips screw driver||4|
|6||Remove the engine mount and engine mounting adapters from the bottom of the engine by removing the socket head cap screws that connect them.||2.5mm Allen Wrench||4|
|7||Remove the exhaust pipe from the engine by removing the two Phillips head screws that go through the engine block into the exhaust pipe. Also remove the air filter by simply just pulling it off the carburetor.||#2 Phillips||4|
|8||Remove the carburetor from the engine by loosening the 6mm nut located on the side of the engine near the base of the carburetor. Once the nut is loose, the carburetor can be pulled out of the engine. After it is removed the cam lock shaft that held it in can be removed by hand by pulling it out in the direction of the nut.||6mm nut driver||2|
|9||Remove the cylinder head from the engine block by removing the 4 socket head cap screws that hold it in place. During this step you can also remove the glow plug wire by simply pulling it off by hand then removing the glow plug with an 8mm socket.||2mm Allen, 8mm Socket||4|
|10||Remove the back plate from the engine block by removing the 4 Phillips head screws from the side. Once the screws are removed the back plate slides out of the side of the engine by hand. The back half of the crankshaft will also come with the back plate.||#1 Phillips||3|
|11||Remove the clutch by pulling the spring clip off the crankshaft end and sliding the clutch drum and the clutch shoes off by hand. Then the clutch shaft can be unscrewed and removed using an 8mm socket and pliers to hold the outer shaft from spinning.||8mm socket, pliers||6|
|12||Remove the cylinder liner from the engine block by pulling it out using pliers. Once the liner is out there is enough room to wiggle the connecting rod off the crankshaft so the piston can be removed. And after the piston is removed the second half of the crank can be pushed out.||pliers||4|
|1||Remove the flat head Phillips screws from the bottom of the car to disconnect the transmission from the chassis.||#2 Phillips||3|
|2||Remove the rear drive-shafts from the transmission by spreading the yokes apart and pulling the u-joint out. This must be done on both sides to remove both drive-shafts. The yoke can be spread with snap ring pliers.||snap ring pliers||7|
|3||Remove the yoke on each side by removing the Phillips flat head screw in the rotational center of each, then loosening the two set screws on each yoke. Then the yokes can be pried off with a flat head screwdriver.||#2 Flathead screwdriver, Pliers||7|
|4||Remove the input gear by holding the gear in your hand and removing the hex nut from the shaft. Then pull the gear off the shaft by hand.||7mm socket||5|
|5||Disassemble the brake assembly by removing the 2 screws shown in the picture. Once removed the entire assembly can be pulled off the input shaft and separated into components.||#2 Phillips||4|
|6||Remove all the Phillips screws on the side of the transmission and pull the two transmission case halves apart by hand. Once the halves are split, all the internal gears can be slid off the shafts that they rotate on.||#1 Phillips||6|
Documenting the connection of subsystem
List of subsystems:
1. Suspension system: It is connected to the chassis
(a)Front suspension: The components of the suspension system are:
1. Two individual shock absorbers
2. Two Control Arms
The front suspension system consists of a frame which physically holds the entire suspension system to the chassis by screws and connects the spindle on which the tire rotates through the individual shock absorbers. The control arms also support the spindle and connect it to the suspension system. There is mechanical energy involved in the suspension because the mass of the whole car makes the spring move up and down using mechanical energy while the parts physically move. The front wheel suspensions are physically linked with its arms onto the chassis so that the weight or pressure onto the ground is balanced in a way that the car does not hit the ground and maintains a sufficient ground clearance.
(b) Rear suspension: The rear transmission system consists of:
1. 2 Shock absorbers
2. Shock tower
3. Two Control arms
4. Two arms
The rear suspension system is held to the chassis by the Shock Tower with screws. the shock absorbers connect the Shock Tower to the axle or the spindle. The Control Arms also connecting the Shock Tower to the spindle support the spindle and allow excess movement of the shock absorbers on rough terrain. The two arms support the Drive Shafts coming from the transmission to the spindle physically linked with its arms onto the chassis so that the weight or pressure onto the ground is balanced in a way that the car does not hit the ground and maintains a sufficient ground clearance. The car uses a control arm on each of the wheels that allows the wheel to travel up and down relative to the main chassis. Then to suspend the car it uses a coil-over shock absorber connected to each of the control arms that will compress when the car hits obstacles to reduce the shock put on the chassis and also to improve handling characteristics. Because the system improves handling, it also improves safety of the car because it is more predictable when driving.
2. Steering mechanism:
The circular white plastic base is connected by screws to the chassis and is also connected to the servo that receives signals from the controller and sends it to the steering mechanism. The two tie rods from the circular steering mechanism connect the spindle which is responsible to move the tire. On the models the servo is attached to at least the steering mechanism; rotation of the servo is mechanically changed into a force which steers the wheels on the model, generally through adjustable turnbuckle linkages. Servo savers are integrated into all steering linkages and some nitro throttle linkages. A servo saver is a flexible link between the servo and its linkage that protects the servo's internal gears from damage during impacts or stress. The steering mechanism is connected with the suspension so that it is able to take turns during bumpy rides depending on the leverage of the suspension. In addition the pressure onto the steering is maneuvered and adjusted sufficiently. It is connected with a servo so as to steer in different directions.
3. Engine and Transmission:
The engine is connected to the chassis and also is interconnected to the transmission by gears . The cylinder head sits on top of the crankcase and has extended or additional cooling fins to greatly increase the surface area of the head, to catch more air for cooling. The piston is connected to the crankshaft by a connecting rod, or con rod; this crankshaft runs perpendicular to the con rod through the crankcase and is connected to the clutch of the car. Sitting at the front of the engine on top of the crankcase is the carburetter, which is the part of the engine that introduces the fuel and air into the crankcase. The fuel / air mixture inside the combustion chamber is ignited by a glow plug, screwed into the top of the cylinder head. The engine is also connected to the transmission. The Nitro Sport RC car uses a two cycle, nitro fuel powered engine to drive the car. The power created from the engine goes into a gearbox where a gear reduction system reduces the rpm and increases the torque. Before the output shaft of the engine can supplie power to the gearbox it must first go through a clutching mechanism that will transfer the rotational energy of the motor smoothly to the gearbox and also alow the engine to spin at idle without driving the car forward. Once the rotation energy has been transferred throught the gearbox it is outputed from the gear box to drive shafts that are connected to each of the rear wheels. The rotation of these driveshafts is what makes the car move. This entire system of taking nitro fuel and converting it to rear wheel turning is a very intersting concept that we wwould really like to investigate further.The chemical energy from the battery ignites the servo to receive radio magnetic waves to which transfers the energy to the engine. The engine converts the chemical energy from the fuel to mechanical energy when the pistons moving up and down produce a rotational energy in the wheels. In addition it gives out a lot of heat thus producing thermal energy.
4. Braking system:
The breaking system is connected to the transmission. They are connected because the breaks forces the gears and clutch to stop the wheels from rotating. The central disc brake system is connected to the throttle servo through which the signals received by the controller adjust the pressure, given onto the brakes which reacts onto the transmission and forces the car to stop. There is frictional energy which gets converted to thermal energy when the breaks are applied.
Screws connect most parts of the car and mainly all screws have the same size. Economically, this is important to reduce the cost of the car because the screws can be abundantly produced, thus the control car is much cheaper and affordable. The nitro fuel is used to move the piston up and down that will eventually move the wheels of the car. Globally, this type of fuel is not easily available. The use of a bigger size 10 bolt that is tightened with the inner drive shaft of the engine provide stronger force so that the engine is safe to operate at higher rotation. Connecting components such as the nuts, screws, and bolts, which are made of steel, can be reused or recycled overtime.
The connection type influences the performance. Subsystems are connected mainly by plastic parts, which are durable and can withstand high impact on the car. It is designed so that full performance of the car can be achieved. For example if the gears and clutches were made of plastic instead of steel, it would not be a durable performance that would prevail. Also if the chassis were made of plastic to reduce cost, it would lead to earlier wear and tear of the product, thus affecting the performance.
Arrangements of subsystems:-
-Suspension consists of two parts, the front and the rear suspension. Both suspensions are directly connected to the tires the tires by the suspension arms. These suspensions make up the same function that is to reduce the damage acted upon the car when the car is moving. When the car moves, the tire will collect huge amount of impact in which the impact is reduced by the shock absorber that can be contract and expand.
- Steering mechanism is placed at front part because it is vital to change the direction of the car when the front wheel is moved instead of the rear. If the rear wheel direction is to be controlled instead of front wheels, the movement of the car will be reverse.
-Engine is placed at the rear part of the car. It is placed side by side with the transmission and is interconnected by gears. When the engine function, it cause the transmission to move that rotate the rear wheels and moves the car forward and backward. Engine cannot be placed at front part of the car because it will require extra gear system to transmit energy form the engine to the transmission and the performance of the car could be reduce.
-Transmission is what rotates the wheels and make the car move forward and backward. It is placed at the rear part because the car is rear wheel drive. The rear wheels are connected to the transmission by the drive shaft that rotates with the transmission.
Subsystems that cannot be adjacent:
-Transmission and steering mechanism cannot be place side by side because both subsystems require direct connection to the front and back wheels.
GATE 3: PRODUCT ANALYSIS
The purpose of this Gate is to present a detailed analysis of each of the Nitro Sport's components. We have examined the product at the component and the subsystem level and compiled detailed information on each component in a table. Also included in this gate of the project is a project management coordination review, the product component evaluation, a solid model assembly of key components, a description of an analysis design problem for the product, and some design revisions that we feel could be made.
CAUSE FOR CORRECTIVE ACTION
There have been two major problems identified by the group members that led to the inconsistency and inefficiency in submitting the previous Gates. We have developed methods to overcome these problems.
Last minute work:Action: Schedule more meetings so that the work load could be spread evenly among the group members and completion of the Gates can be done as early as possible so that the group members are left with enough time for editing, corrections and checking for inconsistencies in the gate before the submission deadline.
Poor Technical Communication:There was lack of communication between the group members that led to vague understanding of what was to be done and how the data was to be presented. This led to inconsistencies in presenting the data and also led to missing some important points that were supposed to be discussed in the Gate. Action: Need to propose a more detailed outline of what is to be covered in the Gate and communication between the group members to ensure what every member is supposed to do when completing the gate.
The following is a list of components for the Traxxas Nitro Sport Truck. Included in the table is the Traxxas Part No. from(www.traxxas.com), Part Name, Part description, function, material/ approx weight, manufacturing process, complexity and a picture. Below is the definition of the complexity scale that the group has used in the table.
The complexity scale for the component is a 1-10 scale.
The component complexity scale is based on form, function, manufacturing methods. Therefore components with intricate design, multiple or complicated functions and manufacturing methods which include multiple processes will be the most complex with a score of 10 on the complexity scale, and the parts made with the least amount of effort and confer to the least amount of functionality will have a score 1 or closer to 1.
The complexity scale for the interactions between the components and the surrounding components is a similar 1-10 scale. If the component interacts with the surroundings statically, such as a simply screwed together, it will hold a low score. If the interaction is dynamic one, such as transfer of rotation energy or other flows, then it will get a higher score i.e, close or to 10.
Weight:Each part was given a rough weight value that was felt relative to some known wieghts.
Note:The pictures have been taken on a 1"X 1" size grid to show the relative sizes and geometric features.
|Part No.||Part Name||Function||Colour||Material/Weight(g)||Manufacturing Process||Complexity||Image|
|4060||Air Filter||To purify the air intake.Output:clean air, input:debris, dust, air||Black||Plastic (8g)||Injection moulding because it is a fast way to make intricate design out of plastic.This satisfies economic concerns.||Component:3, Interaction:2|
|1726||Antenna, tube||To receive signals from the controller.input: electrical signals, output:signals||Red plastic||plastic, metal(5g)||extrusion because it is fast to manufacture and owing to the simple profile||component:1, interaction:1|
|1834||Body Clips||To hold the body parts together that are not to be permanently screwed to the chassi||Silver||steel(1g)||Drawing into steel wire and forming into shape because of the material and the shape||component:1, itneraction:1|
|4514||Body||Look aesthetically cool and to protect the internal components.||Red and white graphics||plastic (175g)||injection moulding||component:1, interaction:1|
|4184||Brake Brackets||To stop the brake disk. These squeeze against the brake disk to reduce the speed of the vehicle. Input:frictional force;Output:Frictional Force||Silver||Steel(6g)||stamping and forming since it is a thin sheet of metal bent to for the shape||componenet:3, interaction:4|
|4185||Brake Disk||it is component of the brake system. It creates friction between the brackets to slow the vehicle. Input:frictional force;Output:Frictional Force||Black||Soft plastic(4g)||injection moulding owing to the flat shape of the part and ease of manufacturig||component:1, interaction:3|
|4183||Brake lever||It pushes the Brake Brackets against the Brake Disk when pulled.Input:Torque;Output:Torque. When pulled, it squeezes the brakets to stop the rotating brake disk.||Silver||Steel (3g)||Drawing and bending owing to the shape of the part and doesnt require accuracy. This process is economical||component:3, interaction:3|
|4132||Bumper(rear)/battery box/body clips||To contain and protect the battery pack||Black||Plastic(80g)||Injection moulding due to ease of manufacturing||Component:2, Interaction:2|
|4532||Chassis deck, upper composite||forms the base which hold the components together.Input:Force;Output:Force||Black||Plastic (100g)||injection moulding because its fast and economical||compoentn:2,ineraction:4|
|4530||Chassis plate||It holds the different componenets of the car.Output:Force;Input:Force||Light Blue||T6 Aluminum(120g)||Stamping of the inital shape, machining of the holes because it is economical||component:4, interaction:3|
|4460||Engine mount, 3 piece||To hold the engine in place on the chassis and to absorb the engine vibrations;Input:Force;Output:Force||Silver||Aluminum(90g)||Diecasting the structure, forming the shapes,maching the holes||component:4, interaction:2|
|4434||Gearbox brace/clutch guard||Reduces chassis flex so that the clutch gear and the transmission gear's center to center distance doesnt change.Input:Mechanical Energy;Output:Mechanical Energy||Black||Plastic(10g)||injection mouldig beacuse its economical and fast||component:2, interaction:2|
|4144||Adapter nut, clutch||To mount the clutch on to the engine crankshaft||Silver||Steel(3g)||Machining:turning because of its axial symmetry.||componenet:6,interaction: 3|
|4120||Clutch bell(20 tooth)||To transfer rotation from the engine to the transmission.Input:Rotational Energy;Output:Rotational force||Grey-silver||Steel(80g)||Machining:Turning of the bell and broaching of the gear teeth because of its complex shape and material||component:7,interaction:4|
|4146||clutch shoes(2)/spring||To create friction with the clutch bell to transfer crankshaft rotation to the clutch gear rotation.Input:Frictional Force;Output:Frictional Force||Black||Plastic(6g)||injection moulding because of its complexity and ease of manufacturing||componenet:3, interaction:3|
|4181||Differential Gear(45 tooth)/side cover plate and screws||transfer rotational energy through the transmission to the drive shaft.Input:Rotational Energy;Output:Rotational Energy||White||Plastic(10g)||injection moulding because its fast and economical||component:3, interaction:3|
|1952||Carriers, Stub axle(rear)(2)||To guide the drive shaft and connect the rear wheel to the chassis.Input:Mechanical Energy;Output:Mechanical Energy||Black||Plastic(3g)||Injection moulding because its economical and because of the size of the part||Component:3, Interaction:3|
|4628||Differential Output Yokes(2)||Connects driveshaft to transmission output shaft.Input:Mechanical Energy;Output:Mechanical Energy||White||Plastic(1g)||Injection moulding and Maching becuase its fast and economical||component:4, interaction:3|
|1951||Half shafts, long truck(external splined)||Transfer rotation from transmission to rear wheel.Input:Rotatinal energy;Output:Rotational Energy||Black||Plastic(5g)||Injection moulding becuase its plastic. fast and easy||compoenent:2, interaction:4|
|2753||Stub axle, pins(4)||Transfer rotation from transmission to rear wheels.Input:Force;Output:Force||Black Plastic,silver metal||Plastic, metal (11g)||drawing, injection moulding, turning owing to the shape of hte part and since its fast and easy||Componenent:4, Interaction:4|
|4550||Exhaust header||To direct the exhaust gas from the motor to the muffler.Input:Gas;Output:Gas||Aluminum(30g)||Forming and Wielding because of its complex shape out of alumin tubing||component:5, interaction:2|
|4452||Exhaust pipe||To direct the emissions away from the engine and reduce the sound output.Input:Gas;Output:Gas||Light Blue||Aluminum(60g)||Forming because its hollow with a chaning profile over its length||component:3, interaction:2|
|4451||Exhaust pipe rubbber||To prevent leakage of emmissions.Input:Force;Output:Force||Yellow||Rubber(5g)||Injection moulding because of the type of material.||Compoennet:2, Interaction:2|
|2530||Bulkhead(front)(black)||Connects the front suspension to main chassis.Input:Force;Output:Force||Black||Plastic(70g)||Injection moulding||componenet:3, interaction:2|
|4439||Shock tower (front)||To hold the Suspension system to the chassis.Input:Force;Output:Force||Black||Plastic(33g)||Injection moulding because its plastic and its fast and its economical||Component:3, interaction:2|
|2640||Suspension pins||Connects the Conbtrol arm to Bulkhead.Input:Force;Output:Force||Silver||Steel(13g)||Forming, Drawing because of the size of the part, and since its fast and easy||component:3, interaction:1|
|4448||Fuel Tank(75cc)||Holds fuel||White||Plastic(32g)||Injection moulding since its fast and economical.Input:Nitro Fuel;Output:Nitrofuel||Component:2, Interaction:2|
|2919||Battery pack||To provide power to the Servos and to the Starter.Input:Chemical Energy;Output:Electrical Energy||Black plastic,silvery metal||Plastic and Steel(80g)||Injection moulding since its fast and economical||Component:2, Interaction:2|
|2019||Receiver, 2 channel||To receive radio signals and convert them to electrical signals to the servos.Input:Radio waves;Output:Electrical Energy||Black||Plastic, Metal (90g)||Injection moulding and soldering due to the presence of a circuitboard inside the receiver||Component:3, Interaftion:3|
|2055||Servo,high torque||Receives signals from the receiver and turns it into rotation energy to control car functions.Input:Radio signals;Output:Rotational Energy||Black||Plastic(80g)||Injection moulding and soldering owing to the complex function of the part and the type of the material||component:3, Interaction:3|
|4192||Bulk Head(Rear)||To support the rear Suspension system.Input:Force;Output:Force||Black||Plastic(30g)||Injection moulding since its fast and economical||Component:2, Interaction:2|
|2555||Suspension arms(rear)(2)||To support the rear suspension system.Input:Force;Output:Force||Black||Plastic(28g)||Injection moulding beacause its fast and economical||Component:3, Interaction:3|
|3760A||Ultra Shocks(2)||One of the main components of the suspension system.Contains hydraulic dampening to absorb shocks.Input:Force;Output:Force||Black plastic,silvery metal||Plastic, Steel spring(11g)||Drawing for springs, Injection moulding for plastic attachments owing to the complex geometry of the subsystem||Componenet:3, Interaction:3|
|3762A||Ultra shocks(rear)(2)||absorbs shock and constitue the main componenet of the rear suspension system.Input:Force;Output:Force||Black plastic,silvery metal||plastic, steel spring(18g)||injection moulding for the plastic housing and drawing process to crate spring becuase owing to the complex structure of the component||Component:3 Interaction:3|
|4593||Adapter, Spur gear||Connects the transmission input gear to transmission input shaft.Input:Force;Output:Force||Black||Plastic(8g)||Injection moulding since its fast and economical||Component:3, Interaction:2|
|4470||Spur Gear(70 tooth)||To transmit the rotation from the clutch to the transmission.Input:Rotational Energy;Output:Rotational Energy||Black||Plastic(6g)||Injection moulding and broaching, owing to the complexity of the part||Component:3, Interaction:3|
|1942||Rod ends(12)||Connects the control arms or tire rods to other suspension components.Input:Force;Output:Force||Black||Plastic(0.8g)||Injection moulding since its economical||Component:3, Interaction:2|
|1937||Turnbuckels(2)||To connect the axel carriers to the chassis||Silver||Steel(4g)||Forming, Drawing and Machining becuase of the structure and the geometry of the part.Input:Force;Output:Force||Component:2, Interaction:3|
|4182||Servo Horn||Controls the throttle and brake linkages.Input:Torque;Output:Torque||Black||Plastic(5g)||Injection moulding becuase its economical and also owing to the size of the part||Component:3, Interaction:4|
|5574R||Tire and wheels(front)||To support the weight of the car and allow it to move and change direction.Input:Rotational Force;Output:Rotational Force||White rim,black tire||Plastic, Rubber, Foam(100g)||injection moulding due to the material and structure of the wheels||Component:2, Interaction:2|
|5572R||Tire and wheels(rear)||To support the weight of the car and allow it to move and change direction.Input:Rotatioanl Force;Output:Rotational Force||White rim,black tire||Plastic, Rubber, Foam(102g)||Injection moulding due to the material and structure of the tires||Componenet:2, Interaction:2|
|4491||Gearbox halves||Incases the gears of the transmission.Input:Static Force;Output:Force||Black||Plastic(7g)||Injection moulding because its plastic and the process is fast and economical||Component:2, Interaction:2|
|4196||Idler gear(20tooth)||It connects the gears in the transmission.Input:Torque;Output:Torque||Grey||Plastic(10g)||Injection moulding since its plastic||component:2, interaction:2|
|6624||Carburetor||Its function is to mix the air with the fuel in a certain ratio so that the mixture could burn efficiently.Input:Air and Fuel;Output:Air-Fuel Mixture||Silvery||Aluminum(80g)||Investment casting because the part is Metal and it has definite intricate geometry||Component:6, Interaction:5|
|6622||Engine block with the flywheel||It incases pistons and the cylinder. It is the main power producing component of the vehicle.||Grey||Aluminum(147g)||Diecasting because of the structure of the block||component:6, Interaction:5|
|6631||Piston and Cylinder||It holds the Air and Fuel mixture for combustion||Black cylinder,grey piston||Aluminum(40g)||Diecasting, Forming to obtain the shape needed.Input:Air-Fuel Mixture;Output:Mechanical Force||Component:3, Interaction:2|
|6683||Engine Head||It houses the glow-plugs for combustion and provide junctions for intake manifold and exhaust manifold.||Silvery||Aluminum(80g)||Diecasting, machining owing to the shape of the Forming to obtain the shape needed.||Component:3, Interaction:2|
|**||2.5mm Socket head cap screws(16)||Holds the steering servo in place on the chassis and other major componenets||Black||Steel||forming and shaping, machining owing to the size and shape of the screws.Input:Force;Output:Force||Component:2, Interaction:2|
|**||2mm Phillips Screws(54)||Holds majority of the parts together||Silvery||Steel||Forming and shaping, machining owing to the size of the screws.Input:Force:Output:Force||Component:2;Interaction:2|
|Part No.||Part Name||Analysis||Picture|
|6622||Engine block with the flywheel||Shape:Symmetrical along the horizontal direction.
Axis-Symmetry:symmetry along x-axis
L X B X W:3inX2.2in,1.5in rad
Component shape coupled to function of component:Shape is made in a way to fit the crankshaft and the Engine Head
Manufacturing decision's involved:Size of the engine, size of the piston, material to be used
Property:Aluminum is light and can withstand high temperature and pressure
4 Factors;Economic:Aluminum is cheap to smelt and produce thereofer is readuily available in the market
Surface Finish:Sand Blasted
Functional or Aesthetic:Functional
MANUFACTURING:Diecasting because if the structure of the block.
|4452||Exhaust pipe||Shape: bottle shape.
Axis-Symmetry:symmetry along x-axis
L X B X W:6inX1in,1in rad
Component shape coupled to function of component:Shape is designed to efficiently direct emission away from the engine and to reduce sound.
Manufacturing decision's involved: Pipe size, hollow size
4 Factors;Economic:Aluminum is cheap to shape and manufacture and can be produce abundantly for a cheaper cost.
Functional or Aesthetic:Functional
MANUFACTURING:Forming because its hollow with a channing profile over its length.
|4470||Spur Gear(70 tooth)||Shape:Disk shaped
L X B X W; 2.3 Dia, 70 tooth
Component shape coupled to function of component:THe part is a gear which is flat coupled to function with the other gears in the transmission box.
Manufacturing decision's involved:Making the precise number of hte teeth for the desired gear ratio,holes on the part for other parts to interact with
Property:Plastic is light and is long lasting.
Influencing Factors;Economic:Plastic is cheap an deasy to produce
Functional or Aesthetic:Functional
MANUFACTURING:Injection moulding and broaching
|****||2mm Phillip screws||Shape:horizontal thread steel with phillip head on top.
Axis-Symmetry:symmetry along x-axis
L X B X W:0.8inX0.5inX0.3in
Component shape coupled to function of component: screws with thread provide more grip when connecting two parts together
Manufacturing decision's involved: thread are strong enough to hold the grip.
4 Factors;Economic:Steel is cheap to smelt and produce therefore is readily available in the market
Surface Finish: good surface finish
Functional or Aesthetic:Functional
MANUFACTURING:Forming and shaping machining owing to the size of the screws .
|1937||Turnbuckels(2)||Shape:Long and cylindrical
Axis-Symmetry:Symmetrical along the horizontal axis
L X B X W;2in length,0.25radius
Component shape coupled to function of component:Part shape is such to tranfer mechanical energy from the steering servo to the axels.
Manufacturing decision's involved: where to get the threads so that it can be turned in its grooves
Property:Steel is strong and able to bear high external forces
Surface Finish:Smooth except for the threads
Functional or Aesthetic:Functional
MANUFACTURING:Forming, Drawing, turning and later machining to get the threads
L X B X W:9.2inX3inX0.025in
Component shape coupled to function of component:Componenet is flat so that it can protect the car from hitting th efloor. It is also responsible for directing the vibrations of the different components that are held together by it evenly
Manufacturing decision's involved:Strength of the MAterial,position of the holes to be drilled on the plate
Property:Strong tensile strength as well as light
Influencing Factors;Economic:Owing to the strength and weight of the material, its easily available and affordable and thereofre has been selected for this part
Functional or Aesthetic:Functional
MANUFACTURING:Forging of the initial shape then machining of the holes
SOLID MODELED ASSEMBLY
As a group we decided to do a solid model assembly of the front suspension. We created an assembly model of the front bulkhead, the front lower control arms, and the front shock tower. We chose these components because of the the unique way that they operate together and their importance in the suspension functioning of the Nitro Sport race truck. To do this assembly we used the Autodesk software because its the only software we know how to use.
Engineering analysis was used in the design of the braking system, more specifically the Brake Lever that connects the Servo to the Brake Brackets that house the Brake disk. The problem identifies the need to alter the length of the Brake lever for an effective Braking power. For that, we will be given the Moment that is applied on the Servo to move the Brake lever. Also, will be given the current length of the Brake Lever, Coefficient of Friction between the Brake Disk and the Brake Brackets, Coefficient of Friction between the Tire and the Asphalt, and Diameter of the Wheel and Mass of the Traxxas Nitro Sport Truck. Data to be assumed should be that Car is running under normal conditions,Acceleration due to Gravity being F =9.8m/s2, Frictions between the gears is neglected. The moment from the servo remains constant.
The Diagram shows the Forces and the moments that act on the Braking system. When the brake is applied, the Servo Horn rotates creating a Moment 'Ms' thus creating a pulling Force Fs on the Connecting Rod of length 'L'. 'Pl' is the horizontal length of the Brake Lever and 'l' is the vertical length of the Brake Lever. The movement of the Brake lever creates a moment 'ML on the Brake Bracket which initiates a contracting force on the Brake Disk spinning at an angular velocity of 'W' and having a radius 'R'.
The calculations are governed by the following equations.
ω=Vl/(R) where ω=(angular velocity of the wheel,gear,brake shoe),Vl=linear speed,R=radius of the wheel, Fk=μk Fn where Fk=Kinetic Friction between the show plates and the shoe
where,μk=coeffecient of friction,Fn=normal force acting when the show plates are pulled against the shoe.
ρ=mv where ρ=momentum of car, m= mass of car, v= velocity of car
Calculations: Solution Check: The value that we get isn’t negative and is legit.
Discussion: Had the horizontal length 'Pl of the Brake Lever been short, more force would have been needed from the servo to pull the rod thus giving an ineffective braking power as the torque from the Servo remains constant. Secondly, had the shoe plates been made of metal and not Aluminum, the coefficient of friction would be less than the obtained value which would make the whole calculation inconsistent.
Revisions are usually made to a product to improve the performance and design. This increases the efficiency, safety features as well as complexity of the product, thus affecting the social, economic, global and environmental factors.
1. One of the design revisions is that the body could be shaped in a sleeker manner so as to give it a better aesthetical appeal on the design. In this manner, it attracts more consumers and gives it a better look, thus affecting its societal factor.
2. An insulating shield could also be implemented on the muffler so as to prevent burns on the skin when in contact with the human body. This increases the safety features and thus affecting the societal factor.
3. A catalytic converter could be installed to the muffler so as to reduce the gas emissions. This converts the toxic exhaust emissions from an internal combustion engine into non toxic substances thus affecting the environmental factor.
The purpose of this Gate is to reassemble the product and to analyze all the information that has been gathered over this gate and all previous gates to make detailed conclusions about the Traxxas Nitro Sport RC Car. This gate includes a project management project review, a section dedicated to the reassembly and explanation of the Nitro Sport RC car, and a section on design revisions that we would consider making to the product. This is the final gate to our project on the Traxxas Nitro Sport RC car.
Cause for corrective action:
Up until now, we have resolved all of the challenges presented and have not come across any new ones. In Gate 3 we had proposed two actions to correct the problems we were having within the group. The challenges we had during the project and actions we took to resolve them are listed below.
1.)Last minute Work:
Scheduling more meetings definitely helped to even out the work load so that the project gate was completed more accurately with more time for revisions.
2.)Poor technical communication:
Communication between group members was greatly improved so that every member is up to date on the detailed group progress on the project.
In this section we will provide a step by step process that describes the reassembly of our Traxxas Nitro Sport RC Truck. Included in this section will be a detailed description of the assembly steps, the necessary tool(s) for each step, how the tool(s) is/are used,and how difficult the reassembly is. All this information is found in the following table.
The Nitro Sport RC car doesn't have the huge consumer base or sales numbers that an automobile or other commonly abundant product has, so we have ruled out that the Nitro Sport is assembled on an automated assembly line. There is no information available on the company's manufacturing processes so this inference is what we feel is the truth. With that being said, we think that the Nitro Sport is assembled from the factory in the exact way that we are assembling it with the possibility of use of power screw-drivers instead of manual ones only to improve speed.
Another detail that you will notice is that the assembly methods and order are exactly backwards of the dis assembly process that we conducted in gate 2.
Note: The difficulty scale is a 1 to 10 scale with (1) being a relatively easy reassembly process for the current step and a (10) being the most difficult possible method of assembly for the current step relative to the difficulty of the processes of the other steps. As a baseline for understanding this scale, a score of (1) would be equivalent to using one common tool, to install a part by one fastener. The score will get higher for single tool with increasing number of fasteners or any complications until the score approaches (5). Assembly processes that score (5) or higher indicate the use of multiple tools. The score will then approach (10) with increase in complexity of part interactions and number of fasteners.
Product Reassembly Process
|1||Put in the pins in the front left and right spindles and then attach the snap-rings using a pair of Snap-Ring Pliers to the ends of those pin to hold each spindle in place. This is the first step for the steering subsystem Assembly.||Snap ring Pliers-Needle nose||6|
|2||Insert the steering servo to the chassis by screwing in the 4 socket head cap screws to hold it in place. They can be accessed from the top of the car. There is a slight complication in this step due to the angle in which the front screws must be screwed in. The use of a ball-end Allen wrench will resolve this. Finally plug in the servo’s wire to the receiver. The receiver is to be located just behind the steering servo.||2.5mm Allen wrench||5|
|3||Put in the steering pitman arm to the steering servo by screwing in the Phillips head screw to be located in the center of the round control arm. The screw has to be put in through the access hole in the bottom of the chassis. Once the screw is placed, the pitman arm can be simply attached to the steering servo spline by hand.||#2 Phillips||2|
|4||Connect the front right and left tie rods to their corresponding spindles by putting in the Phillips head screw at the outer ends of each rod. There is one outer screw per side.||#2 Phillips Screwdriver||3|
|5||Place the front wheels to the car by screwing in the 8mm lock-nut at the center of each of the wheels.||8mm nut driver||2|
|1||Attach the front shock tower to the front suspension assembly main frame. These are the two main components to the front suspension assembly. They can be attach by screwing the 2 Phillips head screws.||#2 Phillips||2|
|2||Attach the car body front mounting bracket to the front shock tower by screwing the 2 Phillips head screw.||#2 Phillips||2|
|3||Attach the left and right lower control arms to the front suspension assembly by screwing the Phillips head screws. There is 4 screws total to attached both left and right control arms.||#2 Phillips||2|
|4||Attach the left and right upper control arms to the front suspension assembly. To do this you must screw the Phillips head mounting screws located at each end of each control arm.||#2 Phillips||2|
|5||Attach the front 2 shock absorbers by screwing the 4 Phillips head mounting screws located at each end of each shock absorber.||#2 Phillips||2|
|6||Attach the entire front suspension assembly to the chassis by screwing the 5 flat head Phillips screws.||#2 Phillips screwdriver||4|
|1||Push in the pin using needle nose pliers. Do this for both left and right control arms.Attach the lower control arm and its hinge by attaching the snap ring on the hinge. This is the first step in disassembling the rear suspension assembly.||Snap ring pliers, Needle-nose pliers||5|
|2||Attach the axle bearing carriers by screwing in the Phillips head screws that connect them to the upper and lower control arms. There are 4 screws total to screw in both left and right rear axle carriers.||#2 Phillips||2|
|3||Attach the shock absorbers to the rear suspension assembly by screwing in the Phillips head mounting screws to connect each shock to the shock tower and the lower control arms. There are 4 screws total to place both shock absorbers.||#2 Phillips screwdriver||2|
|4||Connect the lower control arms and their hinge to the chassis by screwing in the two Flat Head Phillips Screws in each hinge on the bottom of the chassis.||#2 Phillips||2|
|5||Attach the left and right drive shafts to there corresponding axle carriers. First push in the black plastic hex-shaped piece into each of axle shaft by hand. Then push in the metal pin into the axle shaft using a pair of pliers. After the pin and hex piece are pushed in to each side, the axle can simply be pulled in through the axle carrier.||Pliers||2|
|6||Attach the rear shock tower to the chassis by screwing in the 4 Phillips head mounting screws as shown.||#2 Phillips||1|
|7||Attach the battery cover and the battery pack to the car by attaching the spring clips to be located on each side of the battery cover, either by hand or by using a pair of needle nose pliers.||Hands||2|
|8||Attach the upper control arms to the rear suspension assembly by screwing in the Phillips head mounting screws to each end of each control arm. There is some difficulty in screwing in one of the screws because of the screw driver contacting the surroundings. The screw driver still has enough engagement in the screw to screw it in, but it must be done with care so that the screw may not be damaged.||#2 Phillips||4|
|9||Finally,attach the rear wheels to the car by screwing in the 7mm lock-nut to be located in the center of each of the wheels.||7mm Nut-Driver||1|
|1||Put in the second half of the crank into the engine block and insert the piston. Attach the cylinder liner to the engine block using hands.||Hands||4|
|2||To assemble the clutch, screw in the clutch-shaft using 8mm socket.Push the clutch to the crank-shaft while sliding the clutch drum and clutch shoes by hand.||8mm socket, pliers||6|
|3||Attach the back-plate to the engine by screwing in 4 Phillip Head Screws.||#1 Phillips||3|
|4||Place the cylinder head to the engine block by inserting the 4 socket head cap screws to hold it in place. During this step you can also insert the glow plug wire by simply pushing it onto the top by hand then fixing the glow plug with an 8mm socket.||2mm Allen, 8mm Socket||4|
|5||Install the carburetor from the engine by tightening the 6mm nut located on the side of the engine near the base of the carburetor. Once the nut is screwed in, the carburetor can be fixed on to the engine. After it is fixed the cam-lock shaft that held it in can be fit by hand by pushing it in the direction of the nut.||6mm nut driver||2|
|6||Install the exhaust pipe to the engine by installing the two Phillips head screws that go through the engine block into the exhaust pipe. Also fit the air filter by simply just pushing it on to the carburetor.||#2 Phillips||4|
|7||Install the engine mount and engine mounting adapters to the bottom of the engine by fixing the socket head cap screws to connect them.||2.5mm Allen Wrench||4|
|8||To attach the engine mount to the car chassis, put in the screws at the bottom of the chassis that connects them.||#2 Phillips screw driver||4|
|9||Install the electric starter by fixing the 3 Phillips head screws that screw in to the engine block.||#1 Phillips||2|
|10||To install the muffler, you must tighten the Phillips head screw to mount the front exhaust hanger to the chassis. Then attach the previously cut wire by taping it with electric tape to seal the middle exhaust joint so that the muffler and connection tube can be fixed on. Also the pressure line to the fuel tank should be fit by hand.||#2 wire cutters||4|
|11||Install the throttle servo by fixing the 4 Phillips head screws that hold it to the chassis. Then plug in the servo wire onto the receiver.||#2 Phillips screw driver||3|
|12||Connect the brake linkage by tightening the set screw and fixing the color. Also connect the throttle linkage as well. Attach the arms to the servo spline by hand. to install the throttle/brake control arms to the throttle-servo by screwing in the Phillips Head Screw in the center of rotation of the controlling arms.||#1 Phillips,1.5mm Allen Wrench||6|
|1||Insert all the internal gears to the shafts that they rotate on and attach the two transmission case together by hand. After that, screw all the Phillips screws on the side of the transmission.||#1 Phillips||6|
|2||Assemble the brake assembly by screwing the 2 screws shown in the picture. Once the screws has been put in, the entire assembly can be insert to the input shaft.||#2 Phillips||4|
|3||Insert the gear to the shaft by hand. Then attach the input gear by holding the gear in your hand and screw in the hex nut to the shaft.||7mm socket||5|
|4||Attaching the yoke on each side by screwing the Phillips flat head screw in the rotational center of each, then tightened the two set screws on each yoke.||#2 Flathead screwdriver, Pliers||7|
|5||Attach the rear drive shafts to the transmission by spreading the yokes apart and insert the u-joint in. This must be done on both sides. The yoke can be spread with snap ring pliers.||Snap ring pliers||7|
|6||Connect the transmission to the chassis by screwing the Flat head Phillips screws at the bottom of the car.||#2 Phillips||3|
1) Our first design revision on the system level is to remove the starter system from the truck and add it to the remote battery pack that is used to start the car. The way the Nitro Sport is configured from the factory is such that the user must plug the external battery pack (shown in Fig 4.79 )into the truck's wiring harness and depress the red start button on the battery pack to start the engine. While this makes the starting procedure very easy, it has one major trade-off; the starter must remain on the truck during use which adds considerable weight to the truck.
Because the amount of weight is substantial enough to have negative effect on the truck's performance, our design would incorporate the starter motor and its gear box to the end of the battery box so the starter doesn't have to stay on the truck. Therefore to start the engine you would have to simply plug in the glow plug wire, place the starter unit over the exposed end of the crankshaft, and push the start button. Once the engine starts the glow plug wire can be pulled off and the entire starter assembly can be removed from the truck.
While we understand that this makes the starting process more involved, we feel that the performance gain would far out-weigh the additional step of plugging in the glow plug wire.
The weight reduction of approximately 200 grams achieved during operation is the effect of removing the starting components from the truck(shown in Fig 4.78). The components are also shown in (Fig 4.79) below. In this figure the starter and gear box are circled in yellow, the glow plug wire is circled in red, and the wire harness is circled in green.
The total system is shown in (Fig 4.79). All of these components would be combined and arranged in a manner that makes the process we described previously possible. Because there isn't any new components with our new configuration, the overall cost of the product will not increase. The economic factor of overall cost influences this redesign and the gain in performance with no gain in cost is very appealing to the consumer.
The societal factor influencing this redesign is the way that the consumer uses this product. Because the Nitro Sport is used to race, the consumer will be very happy to have this truck that is lighter, which in turn makes the truck faster and improves handling. This increase in performance will give them a competitive edge against their competitors.
2) Our second revision is to replace the 2-stroke engine with a 4-stroke engine. Because the RC 4-stroke engine has already been developed and is commercially available, there will not be any additional development of the engine by the company needed. This design revision is a simple system exchange.
The move to a 4-stroke engine is influenced by many factors. The first of the factors is the economic factor of operating cost. While the Nitro Sport will cost more initially, the operating cost will be greatly reduced. This cost reduction can be credited to the cost of fuel for a 4-stroke being cheaper, and the fuel efficiency of the 4-stroke engine being greater than that of the 2-stroke.
Another influential factor is the environmental factor of air pollution. Because the 4-stroke engine does not burn its lubricating fluid like the 2-stroke does, it will expel considerably less pollutants. With air pollution being a current concern of many people, this decrease in pollution will be appealing to those consumers and influence them to buy the Nitro Sport versus other comparable models.
Shown below is the original 2-stoke engine in (Fig 4.80) and also the proposed 4-stroke engine in (Fig 4.81).
3) Our final revision would be to replace the single speed transmission with a two speed, automatic transmission. Like our second design revision, this revision is a system exchange. The single speed transmission is limited to a fixed gear ratio which has been factory calibrated to provide the nitro sport with a good combination of acceleration and top speed. The downside, if not obvious, is that with the single degree of freedom (gear ratio), the optimal acceleration and optimal top speed can not be achieved simultaneously. With the addition of another gear, the truck has more degrees of freedom and can better optimize the acceleration rate and the trucks top speed.
The reason for this this design revision is based on the societal factor of the intended consumer and how they use the product. Because the Nitro Sport was developed for racing, performance is a main priority. So people who purchase this entry level RC car are going to want a car that will be competitive in the racing world. The two speed transmission will have a huge performance increase with very small increase in initial product cost. This huge performance gain will help the consumer justify spending a small amount more to purchase the Nitro Sport.
Shown below is the single speed transmission that comes as standard equipment on the Traxxas Nitro Sport (fig 4.82). Below it is the two-speed transmission that has already been developed and used in other Traxxas models (fig 4.83).