webpage last updated on: 06.05.2008
   TEAM  FORMULA  SRIJAN   BIT Mesra

AWISHCAR   :   FS - 07

AWISHCAR ( FS-07 )

Team Formula Srijan from BIT Mesra participated with FS-07 ( the first Formula SAE style car from BIT Mesra ) in its maiden attempt at the competition in July 2007 at the British Grand Prix circuit, Silverstone, UK.

 

List of Contents

 

Achievements

# The team received appreciation from various eminent personalities from automotive industry for its effort in bringing 2 cars for 2 classes of competition.

# We ended up 5th in class2 event and 58th in Class I event out of total 105 teams that had participated from various leading universities around the world.

# Our team is among the very few that can boast of passing the scrutiny as well as entering the final 22km endurance race in its first year participation in the event.

# Team also won 2nd position in presentation event of Class II.

# FS-07 was declared the most economical car in the cost event.

# We were just a team of 8 students & we fabricated 1 working prototype and 2 cars within a span of 4 months.

 

Specification

* Engine: Suzuki F5A 543cc SOHC twin- radiator, liquid cooled

* Maximum Power: 47 BHP

* Maximum Torque: 66 Nm

* Transmission: Suzuki 5-Speed Bevel Gear

* Maximum Speed: 150 kmph

* Body: Fibre-Glass Reinforced Plastic

* Suspension: Multilink double wish-bone suspension

* Steering: 1:2.2 Quick Ratio Rack and Pinion

* Wheel Assembly: 13inch Aluminium Wheel 145/70 R12 Radial Tyres

 

The Making of AWISHCAR (FS-07)

The designs of FS-07 were ready by the mid of Jan’07. To check its stability, we made two static models of chassis, firstly the carton model where we used waste cartons while the second model was a wire model made using wires of copper. On 1st Feb’07 we started working on the chassis and by the 3rd Feb’07 we had our chassis ready. We had decided to make our 1st running prototype using parts from the thrown away vehicles inclusive of the engine. Our first prototype was fabricated on the lines of a Maruti 800 car with an engine of an RD-350 bike. But once again making a hybrid was never easy as the two different vehicle parts had different specifications and it was never an easy job to couple the two different automobiles. Their spare parts had different specifications, sometimes it became really tough to combine the two vehicle parts but at the end our, along with our supporter’s hard work paid and by the 8th Feb’07 we had our vehicle ready and it was the day when FS-07 was first exhibited in the Institute. It was the final day of the International Unnayan 2007 and the car was inaugurated by the Chairman of FICCI and was also witnessed by the Vice President of L&T. But the vehicle wasn’t there in its running condition and it required another 10 days of continuous efforts to bring the vehicle on the roads. As a matter of fact the car ran for the first time on the power of the engine on the 18th Feb’07. And after several testing of the car on the Ranchi roads we decided to give a road show of the car on the roads of our own Institute. We decided 25th Feb’07 as an appropriate date and the Road show was a huge success as it was covered in National as well as local Newspapers and also on one of the local News Channels. Once we tested our prototype successfully we decided to fabricate our final car and to get the spare parts the team divided itself into 4 parts. One of the sections stayed at the Institute while the rest went to Chennai, Coimbatore, Hyderabad, New Delhi etc. As of today the orders have been placed for all the spare parts and they are on their way to Ranchi and as soon as the parts are in Ranchi, the team would be on its toes again.

Thats all that has happened with Team Formula Srijan over a period of 3 years and since this is the inaugural edition of what we call as the annual magazine of the Team Formula Srijan it contains all these information. The upcoming editions will only contain the details of what has the Team done over the passed one year.

 

DESIGN REPORT of AWISHCAR (FS-07)

This is the design report submission for the FS-07; the entry by the BIT Mesra Racing Team into Formula Student 2006. The FS-07 is a first time entry at the formula student competition yet it is an attractive product to the target market. In summary:

• The approach adopted by the team while designing and fabricating the car was to demonstrate a prototype car for suitable as a production item.

• Therefore, the focus was to have a car with very high performance in terms of its acceleration, braking, and handling qualities.

• The differential arrangement has been made by coupling the Japanese Suzuki Engine with an Indian Maruti Suzuki Differential-Gearbox assembly which cuts complexity in the product and adds a Unique Selling Point to the car.

• The FS-07 is assembled from fewer parts after using elimination process, many of which are common and make the car more appropriate for the intended manufacture volume.

• The key features of the car are its aesthetics, comfort and use of common parts.

The team has employed a range of analysis and testing techniques during the design and build of the FS-07 to achieve these features. These are referred to throughout the report.

The dimensions were chosen so as to accommodate the variety of driver sizes in our team, i.e. 5’4” to 6’2”. This was done so as to have a chassis frame compliant with all the rules mentioned in the FSAE rulebook.

2.1 Brake system

The brake system comprises of disk brakes on all four wheels. The brake system is of hydraulic type and utilizes majority of the parts from Maruti 800, which is India’s longest selling and the most inexpensive car to date. Only the master cylinder has been made using two clutch cylinders linked together so as to have a single control. Hence the car is equipped with a braking system that acts on all four wheels and is operated by a single control. It consists of two independent hydraulic circuits having their own fluid reserve by the use of separate reservoirs. The brake discs are identical front and rear purchased from KBX. The pedal box is student designed to provide significant rigidity, following problems with an off the shelf box installed in the test prototype.

2.2 Engine & Drivetrain

Initially we were on a lookout for a 600cc superbike engine. The choice made on the basis that majority of the teams participating in the FSAE events chose either Yamaha or Honda engines for powering these vehicles. The various problems associated with this setup was to have a suitable differential unit which has to be at the same time light weight so as to keep the overall vehicle weight low. The cost of the engine, gearbox & differential unit would have been somewhere around the range of 5,000 $ - 6000$ as per Indian currency rates. Co-incidentally we got an engine from a junk market in Delhi along with an Indian-5speed maruti gear box which fitted perfectly with the engine for just 900$ approximately. This gave huge savings in terms of costs and greatly reduced the complexities of designing. The intake runners have been tuned to use the pressure waves generated within to provide power boosts at desired RPM’s. The system is student designed and results in a three pedal box with common master cylinders. Moving on to the drivetrain, the rear end of the car is designed to jack around extreme corners.

2.3 Frame & Body

The space frame chassis for the FS07 car developed by BIT Mesra India has been developed taking care of the all the rules and regulations of the competition. FS07 being the first year car has been designed to reduce weight and size, whilst providing a more comfortable driving position and larger cockpit area to reduce driver fatigue and taking care of the driver egress time . The chassis uses MS Steel tube space frame(Mild steel tube - cold drawn seamless) with welded MS floor panels .The chassis of FS07 car was completely designed in CATIA .The focus of the design was to comply with all the rules and regulations while taking care of the ergonomics of the system. The final design was optimized in ANSYS. The design utilizes a stressed engine and all load paths have been optimized to transfer the loads into the engine. Space frames are fabricated from dozens of circular-section tubes (some may use square-section tubes for easier connection to the body panels, though circular section provides the maximum strength), positioned to form triangles with the major loads applied at the intersections of three or more tubes. This provides the maximum mechanical strength against forces as the chassis members theoretically only experience loads in tension and compression, rather than in bending. Tests carried out on the FS07 chassis illustrated that the positioning of the side Impact Beams were interfering with the driver’s arms. These problems were overcome through extensive CAD and physical design optimization. The final design provides more room around the arms and knees as well as a more comfortable driving position. Being the First Year team, we had to go rigorous process of prototyping. Initially a fully built running car was designed and tested, which was followed by physical and software design optimization. The steering rack has been roof mounted to provide more space to driver’s legs as this space would otherwise be unused and allows a direct line along the steering linkages. The front suspension components have been placed either side of the drivers legs which helps in keeping the centre of gravity low and in turn minimizing the angles through which the suspension forces are transmitted. The fire wall has been manufactured from lightweight glasswool which is enclosed in a glass fabric to form a quilt . The seat is to be molded from Fiber Reinforced plastic material keeping 95 percentile male as a reference mankin. The Fuel tank has been positioned centrally between the driver (behind the Drivers Seat) and engine to lower the Centre of Gravity of the car .Finally the aesthetically appealing bodywork is constructed from Fiber Reinforced Plastic.

2.4 Instruments & Wiring

The electronics has been kept to a minimum in FS07 car. Analog Design was preferred over digital design, as the parameters can be directly calculated with the ease of installation of the analog components. Speedometer and Tachometer have been used to calculate speed and engine speed respectively. Future version of the FS07 would emphasis on the use of a engine with programmable ECU to enhance the engine performance. All wiring in the car has been properly insulated to prevent it from short-circuit and heat of the engine.

2.5 Miscellaneous Fit & Finish

A particular feature is the FS07 seat which is FRP molded to fit the driver through the use of slider mechanism .The driver heights are in of the order of 5.4 feet to 6.2 feets.The biggest challenge for the design department of FS07 car was to make design of the seat to best fit every driver , which was taken care by a unique slider mechanism installed in FS07 car.

2.6 Steering System

The steering system comprises of a custom built quick ratio racing rack and pinion steering system (2.22 :1 ). This enables the car to have sharp and precise handling capabilities. The quick ratio steering coupled with the short wheelbase gives the car superb handling.

2.7 Suspension & Shocks

The rapid prototyping led to the reduction of the wheelbase from 1810 mm to 1670mm, and the average track from 1510mm to 1470mm. As a result, the car has significantly lower yaw inertia and is able to turn tight corners quicker and more responsively. The FS07 car had a number of fundamental problems with the suspension and steering setup. FS07 car utilizes multi link suspension system which has the advantage of, no lateral play in the suspension and it also gives easy and cheap repair of parts. Firstly, The team was unable to quantify camber change in bump and cornering accurately. Manually parameters were determined. The camber variation was found to be between 3degree to7degree. The roll centers have been set as 40mm for front and 49 mm for rear as the team expect a relatively horizontal centre of gravity line along the length of the car. The FS07 employs the custom built shocker using the Gabriel shockers. Wishbones have been designed to elastically sustain the load. The wishbones have been optimized at these loads to give an outer diameter of 19mm and a wall thickness of 1mm, a lighter setup. Smaller and lighter rod ends have been employed at the chassis, and spherical bearings are used at the upright. The uprights, front and rear are custom built Weight reduction has been achieved at the rear, with a vast improvement in stiffness through FEA optimization in ANSYS. Tie rod adjustment method has been introduced at the upright end to enable camber change but caster and King Pin inclination will be fixed. The most Innovative geometry was the use of adjusting toe in and toe out with the steering arm ends.

2.8 Wheels & Tyres

The FS-07 will sit on alloy rims which have been purchased as off the shelf components. The tires too have been purchased from Hoosier Tires UK as they are the preferred tires amongst the FSAE teams around the globe. A key factor for choosing alloy wheels was that they reduce the unsprung mass hence improving the overall dynamics of the car.