this presentation may be useful for students who want some guidance in SAE BAJA

1. Project by:
Team Thunderbirds
(SAE BAJA 2015)

2. Thunderbirds set out to design and construct
an all-terrain utility vehicle. The team’s vehicle
the trendnought ,has two treads to allow it to
traverse a wide variety of terrains such as
snow, mud ,grass and gravel.

3. BRIGGS AND STRATTON
Briggs & Stratton is the world's largest manufacturer of air-cooled
gasoline engines primarily for outdoor power
equipment. Current production averages 11 million engines
per year.
Briggs & Stratton engines are commonly used on lawnmowers.

4.  Displacement [cc] = 306
 Bore [mm] = 82
 Stroke [mm] = 58
 Weight [kg] = 25
 Oil Capacity = 1.1
 Compression Ratio = 8.0 to 1

5. MAHINDRA ALFA
 The Alfa is a three wheeler goods carrier
designed to make the loading, transportation,
and unloading of small cargos easier.
 Mahindra equipped the Alfa with the largest
and strongest cargo box yet at 24.5 cubic
feet, and then adapted the structure to
handle oversize loads.

6.  Engine Type = 4-stroke, Single Cylinder, air cooled diesel
engine
 Displacement = 395.00 CC
 Maximum Power = 5.51 KW @ 3600 rpm
 Maxiumum Torque = 16.7 Nm @ 2200-2800 rpm
 MaxSpeed = 53 Kmph
 Transmission = Constant Mesh
 Clutch = Multi Plate Wet Clutch
 Gearbox = 4-speed

8. Mechanical
The engine and power train option that was considered was a
mechanical gearing system powered by an internal combustion
engine. While the mechanical system can’t provide the zero-turn
capabilities as simply as hydraulic or electric systems can.

9.  Primary gear ratio=2.86
 Secondary gear ratio=2.38
 Final gear ratio=primary gear ratio*secondary gear
ratio*individual gear ratio
Gear Individual Gear ratio Final gear ratio
1 4.62
31.45
2 2.75
18.70
3 1.67
11.40
4 1.08
7.35
Reverse 8.09
55.05

10.  TORQUE=Maximum torque by engine*final
gear ratio
Gear Torque(N)
1 587.80
2 349.50
3 213.06
4 137.37
5 1028.88

11.  Radius of wheel=0.317m
 Force on wheel=torque/radius
Gear Torque(N) Radius(m) Force(N)
1 587.80 .317 1854.25
2 349.50 .317 1102.52
3 213.07 .317 617.94
4 137.37 .317 433.34
Reverse 1028.88 .317 3245.67

12.  RPM =Engine rpm/final gear ratio of different
gear engine rpm=3800
Gear Engine rpm Final gear ratio rpm Rps=rpm/60
1 3800 31.45 120.82 2.01
2 3800 18.70 203.20 3.38
3 3800 11.40 333.33 5.55
4 3800 7.35 517.00 8.61
reverse 3800 55.05 69.02 1.15

13.  Circumference=2흅r
 r=0.314
Gear Speed=rps*2 pie r in m/s
1 4.07
2 6.74
3 11.05
4 17.15
Reverse 2.28

14.  Aerodynamic drag=0.5 *p*A*V*Cd
 A=frontal area of vehicle=1.0966
 Cd=coefficient of drag=0.6
Gear Aerodynamic drag
1 6.33
2 17.93
3 48.27
4 116.13

15.  Rolling resistance =mg*Crr
 m=mass of vehicle=250kg
 g=accelaration due to gravity
 coefficient of rolling resistance=0.15
 total resistance =drag+rolling resistance
Gear Rolling resistance Aerodynamic
resistance
Total resistance
1 367.5 6.33 373.83
2 367.5 17.93 385.43
3 367.5 48.27 415.77
4 367.5 116.13 483.63

16.  Tractive force =force on wheel-total
resistance
Gear Force on wheel(N) Total resistance Tractive force(N)
1 1854.25 373.83 1480.42
2 1102.53 385.43 717.10
3 617.94 415.77 202.17
4 433.34 483.63 50.34

17.  Acceleration=tractive force/weight of vehicle
Gear Tractive force Acceleration Time taken
1 1480.42 6.02 0.66
2 717.10 3.02 2.32
3 202.17 1.16 4.36
4 50.34 1.08 11.34

18. Components Cost
Frame & Body 40,000-/
Suspension 20,000-/
Wheels & Tires 50,000-/
Steering 10,000-/
Breaks 15000-/
Engine & gearbox 60000-/
Instruments & wiring 10000-/
Driver accessories 50,000-/
Logistics & travel 40,000-/
Promotion & merchandise 20,000-/
Competition fees 50,000-/
Total 3,65,000-/
Engine & gear
Total Rs3,65,000

19. Engine & Gearbox:
Standard B&S engine, Mahindra Alpha Transmission.
Components Cost
B&S Engine 35,000
Transmission 19,000
Labour Cost 6,000
Total 60,000

20.  It is used to get various speeds in different load
conditions.
 It increases fuel efficiency.
 Increases engine efficiency.
 Need less power input when operated manually.
 They are more practical when there is a space
limitation.

21.  Robust transmission and longer gearbox life.
 Best suited for Briggs and Stratton engine.
 Compact and easily available in the market.
 Data of Specification and features are easily
available.

22.  www.bajasaeindia.org/
 www.irdindia.in/journal_ijmer/pdf/vol1_iss1/17
 www.mahindrasmallcv.com/bolero_alfa_passenge
r_diesel
 www.grabcad.com/library/briggs-and-stratton-
10hp-engine-for-baja-sae
 www.briggsandstratton.com
 www.mahindrajhbsouth.co.za/mahindra-alfa-specifications/
 grabcad.com/library/mahindra-alfa-champion-gearbox-
1

23. Thank you!