Bullet santi is a motorcycle driven motor vehicle. It is an attachment which converts a motorcycle into a mini-tractor. It can be attached to any motorcycle havingat least 325 CC(6.5 hp) engine. Rear wheel of the motorcycle has to be removed and innovative assembly unit has to be attached to motorcycle.
Various agriculture attachments can be attached to it for various form of operations like shallow ploughing, inter-culturing, weeding, sowing etc.

Bullet Santi made by a small farmer Mansukh bhai Jagani in 1994 who didn’t had any kind of engineering knowledge. He used to work in diamond factory, lately he learned welding and started working as a mechanic. He converted a petrol engine of bullet bike into diesel running engine and replace rear wheel by an attachment consisting various farming tools. Slowly with time more modifications were made and now there are aprrox. 9- 10 main variations in all models and 200 manufacturers with a huge market of 10000 customers. Therefore even a small modification can serve a lot. Some of them left farming and started production of bullet-santi and selling 60-70 machines every year. They are experts in this field.

The objective is to design an efficient Bullet-Santi overcoming the problems in the previous version of it.

We met Prof.  Anil K. Gupta and he gave us insights of the process of innovative and design thinking. And also made us clear about the objective of the Summer School as it was  organised to present an optimized version of “Bullet Santi”. Prof. Gupta also showed us a 3- dimensional model of innovation which proved to be very helpful. 

After that he also explained the problems being faced by the farmers of Kenya as “SRISTI” is taking the “Bullet Santi” to Kenya. So, that we can come up with the solutions of those problems too.

Field Visit

Grambharti

 

Team went to Grambharti  then we met  Mr. Mahesh Patel, Head of GIAN (Grassroot Innovation Augmentation network) at NIF. He has been connected to this project from the very beginning hence he was the right person todiscuss  proposals for improvisation in the model.

                                                                           

One of main agenda was to work on the standardization of Bullet Santi which means that all fabricators will use the same parts. The process of standardization will be very helpful for legalization of Santi Later discussedour ideasand areas where modifications had been done.

                                                                            

Mr. Vipin gave us his opinion to work on 3 wheel model because this machine is better than tractors  for inter culturing of BT Cotton and groundnut also because farmers are more acquainted with three wheel model hence they are not willing to accept the four wheel model. The four wheel models also increases the cost of Santi thus making its cost comparable to Tractor which decreases its need.

Amreli

We met shanti’s fabricators in amreli, they were very coordinating towards our questions & concerns. They put away their regular production just to answer our questions.

Farmers were almost satisfied with current model & its an hard task to still improve bullet shanti.

Fabricator which we first met ,used an alternative of  double speed reduction differential by adding one more gear of 1:4 ratio in Maruti  Omni gearbox  as shown below.

Adding gear to currently available gearbox successfully is a challenging task easily completed by small scale fabricators.

Other then that a farmer told us that Hydraulic Plow still needs dead weight on it for proper plowing so this is a problem & still needs to be solved.

Discussion

Team had discussion about various features of bullet-santi, necessary changes for its improved performance, various systems that could be incorporated for its better functioning etc. Mr. Chetan Patel guided us throughout this discussion. Students delivered their ideas for changes based upon the field trip to Grambharti on 13th june 2014. Ideas such as introduction of steering using ideal gear, implementation of double reduction technique, use of hydraulic system etc were presented. The team then saw bullet-santi and analysed each and every part of it.

The next topic of concern was to list out the important questions that could be asked from farmers and fabricators separately. Everybody delivered their different opinions. I suggested to focus on ergonomic factors as well apart from the technical problems with bullet-santi. I also suggested to jot down the expectations of the farmer from the vehicle. This could provide a direction for the team members to work so as to improve bullet-santi.
 

Fabricators could tell the parts that were damaged more frequently and hence those could be worked upon.

Challenges

To resolve the handling problem of bullet santi

Hard steering is the major problem, so to enable easy steering with ergonomic feature we decide to prepare a set of gear with its prescribed gear ratios which reduces the effort and resolve this problem.

Problem: Depth Control

In current situation, farmers are using hard and bulky rocks to maintain constant depth which is considered inefficient and also damages the implement. No depth control adjustment facility for plough.

To solve this we decided to implement the hydraulic system with its components to prevent the usage of rocks.This system enables the farmers not to adjust again and again the agricultural tool.It automatically sets the depth of the tool and reduces manual effort.

Draft Control

When all the modern tractors are equipped with draft control, Bullet Santi lags behind all due to absence of this feature. It is a mechanism equipped generally with all tractors with depth control system.
Most the farmers face the consequence of absence of draft control in the system, still they don’t realise it as most of them use stones for applying load on the plough and remove it whenever required. First of all lets understand the use of draft control. In most of the farming applications, a situation arises when the plough or harrow gets stuck in marshy land or due to any big obstacle in the way. This in turn causes load on the axle and finally leads to failure of axle, so here comes draft control in the picture. This mechanism works on the principle of hydraulics. Whenever the attachment gets stuck in any obstacle, this system lifts the attachment from the ground automatically and then again after the obstacle passes by, places it back to its initial position. Thus, all the situations where load arises on the axle of the wheel can be avoided. Furthermore, it reduces the usual practice of mounting and un-mounting of stones on the attachments while its used.
It can prove to be really helpful feature for the farmers because it reduces effort and time and more essentially, it can save the danger of failure of axle.

Damping the Vibrations

Bullet shanti vibrates due to two reasons

1. Absence of rear suspension.

2. Due to stationary diesel engine.

3. bullet shanti is operated on rough agricultural land hence vibrations up to a certain extent can not be avoided.

using suitable alternative automobile engine instead of the current stationary engine can would also help in reducing the vibrations & chassis.

DESIGN Challenge

To design a new efficient working plough has always been a challenge. Owning a tractor and some farming tools helped me in understanding the situation better. I had keenly observed the conventional ploughs used for “Tractor” and “Bullet Santi” therefore I came up with a design of a plough which is basically a compact version of a tractor’s plough. In the field visit to Amreli I had seen a similar type of plough which I had in mind but it had a few shortcomings as it was mechanically week.

One of the main advantages of this plough is that it will provide stability to “Bullet Santi” and will not break easily as it will have many ploughing arms attached with springs to the frames. So, on applying very high load initially, the spring will get stretched and if it crosses its limit, the spring will get bailed out of the plough preventing damage to plough and the farmer can put it back. As the frame is quite heavy so the farmer doesn’t have to put an additional weight…

Users and Fabricator related problem.

 

CHALLENGES ON THE BASIS OF OBSERVATIONS

 

USER ->

  • Starting the vehicle is a challenge for a user as it requires high strength and causes pain in different parts of the body.

  • Handling of bullet santi requires practice. It is difficult to plough the field without damaging the crops, in other words, to drive it straight is itself a painful task.

  • Turning the vehicle in small radius, so as to cover maximum area of land at one go.

  • Ergonomic factors are a major concern. Continuous use leads to back pain, shoulder pain etc.

  • Avoid toppling of the vehicle while driving.

  • Farmers need an extra person to stand on the plough to provide enough weight in the models without hydraulic systems.

  • The manual lifting of plough diverts concentration during driving and it is also very heavy.

 

MANUFACTURER ->

  • Reduce the weight of bullet santi to some appropriate value so as to balance both proper soil aeration and avoid toppling due to light weight.

  • To introduce kick starting mechanism or self-starting mechanism and route out rope mechanism which is ineffective.

  • To provide proper customer service once after the vehicle is sold. So that they can overtake the major advantage of a company tractor over bullet santi.

  • To introduce draft control mechanism to avoid damage of plough with comes because of its frequent strucking in the lumps of soil and stone.

  • To manufacture the vehicle with fresh parts so as to increase its life.

  • To incorporate more functions which are available in a tractor.

  • To modify it so that it can be used for other crops also.

  • To reduce turning radius of the vehicle.

  • To improvise the vehicle and also reduce the cost at the same time.

Suspension problem

We mounted the suspension system on front wheel and attached its lever to the gears of steering just to check if it is working or not. But it was so heavy that direct welding with the chassis wouldn’t hold this and would result in breakage. We asked one of the professor of Lj to give us the idea to solve this problem. He told us that it would be so difficult to attach this heavy suspension and asked us to remove the steering and attach the handle again that we removed.

 

But, we wanted to check if steering could somehow reduce the effort, so we sticked to our plan. But, on mounting the suspension system properly, an offset was generated which shifted the frontwheel to the right side from steering as it is the steering of the mahindra champion and they are designed to have an offset. 

So in order to eliminate this problem, we decided to invert the position of steering that would result in inverted mechanism of steering. That means on turning the steering to the left, the Santi will turn right and vice versa. Since,it is a testing process, thats why we inverted it to check the turning effort. Thats so obvious that this steering could not be used in our Santi. But, if this testing become successful, the new steering for Santi could be designed.

Proposed solutions

 

Thinking of solutions : gear mechanism

 

  • Using Bevel gear

To use four bevel gears. Out of which 3 are work and one remains idle. Of the three working gears, each gear is connected to the other two orthogonally. Thus when the handle turns, gear connected to it moves, moving all three gears with it. Hence Santi bends. This idea has an anomaly. It does not reduce the force required to bend Santi. As all gears must have equal number of teeth to make a perfect square. Keeping the gears similar will not solve the problem. Hence this solution was ruled out.

  • Three gear mechanism

In this mechanism three gears are used. Handle is replaced by a steering wheel, which is connected to a gear. Two other gears are placed after it, from which third gear is connected to the wheel. This arrangement reduces the effort with a feasible arrangement. After debating over the possible solution, the team identified the three gear mechanism as a possible solution to eradicate the crucial problem of heavy handling. Another program of visiting the farmers and fabricators is planned to clear queries of interns. For which a questionnaire is prepared.

Proposed solution: Vibrations

 

There may be three ways to solve vibrations of santi. 

1. To use automobile engine instead of stationary of same specification. An automobile engine is of less weight &  dynamically stable as to reduce vibrations due to engine.

 2. Use rear suspension.

By using rear suspension vibrations & shocks due to ground irregularities could be corrected  as so to provide driver a bit more of comfort.

3. Attach rubber  bushings below engine

Vibrations due to engine could be easily reduced by putting rubber pads below engine to damp engine vibrations & stop them to transfer vibrations to chassis.

working on steering system

 

we visited scrap market of Danilimda to look for a feasible steering system.
We examined the system and decided to use recirculating ball screw mechanism.
We also purchased one of its model previously used in Mahindra Champion.

 

The recirculating-ball steering gear contains a worm gear. You can image the gear in two parts.

The first part is a block of metal with a threaded hole in it. This block has gear teeth cut into the outside of it, which engage a gear that moves the pitman arm .

The steering wheel connects to a threaded rod, similar to a bolt, that sticks into the hole in the block. When the steering wheel turns, it turns the bolt. Instead of twisting further into the block the way a regular bolt would, this bolt is held fixed so that when it spins, it moves the block, hich moves the gear that turns the wheels.

Dematerialization

Dematerialization refers to the absolute or relative reduction in the quantity of materials required to serve economic functions in society. In common terms, dematerialization means doing more with less. Dematerialization is the counter argument to the idea that economics is only about ‘more is better’.

How to select type of tubing for chassis?

Many professionals choose Drawn over Mandrel (DOM) steel tubing for the frame material. As it refers to high strength, electrically welded tubing that has been further processed by cold drawing through dies and over Mandrels to improve its uniformity, mechanical properties and surface finish. The joints in the current chassis are at 90 degree, where we don’t even need it whereas in tube chassis there will be less joints as we can bend the tube as per our need. The structure will be more aerodynamic and instead of fastening by nuts and bolts we can fasten the whole tube chassis with welding.

 

What type of welding to be used ?

Of all the welding process available the gas metal arc welding (GMA) and gas tungsten arc (GTA) welding processes are best suited for TUBE WELDING.

Proposed modifications on Santi

 

Mr Jainil Bhatt,MD,I-Cube joined us at workshop and analyzed the whole model and thus proposed some modifications that could eliminate existing problems in Santi viz. Handling, Excessive Vibrations, Balancing, Axial breakage.

 

BALANCING:

– Two wheels at small gap or a wider wheel can be used instead for better handling and wedge plates could have been used      for    protecting the crops from damage.

– Chassis should be made of either box channel or C- channel as they are most durable.

 

VIBRATIONS:

–  Automobile engines can be used instead of stationary engines in Santi because vibrations caused by them cannot be               damped to larger extent.

–  Refilling the absorbers for better functioning.

 

AXIAL BREAKAGE:

– Hollow axle should be used instead of solid one.

– Regular maintenance is also the solution for avoiding failure of axial.

Apart from these modifications, there is a great need for CAD analysis of Bullet for analysing the weight distribution and effects of load on the axle as without analysis it would be very difficult to eliminate the shortcomings of Bullet Santi.

Prototype

Type 1

It is easy to dismantle and can be again used as a regular motorcycle.

It can also be used for transport purpose by attaching a small trailer.

Type 2

It requires only half-hour to carry out cultivation in one acre.

Type 3

It is capable of performing all agricultural operations done by bullocks.
It is multi-purpose meaning the device can be used even for spraying and other agricultural operations.

Bullet Santi

 

Mansukhbhai jagani

Advantages

1. Bullet Santi is cost effective as compared to tractor.

2. Gross vehicle weight of Santiis approximately 380kg, which is less than the weight of mini tractor.

3. Use of Telescopic suspension in Santihas higher shock absorbing capacity.

4. Usage of hydraulic in Santiwill reduce effort. 5. Arrangement of power take off shaft.

 

Disadvantages

1. M.S chassis, it corrodes easily. It is of a weak material as compared to Cast Iron.

2. Use of Ambassador differential, which increases weight of Santi.

3. Use of 10.5hp stationary engine causes problem of vibration.

4. Telescopic suspension increases the maintenance cost, while working in marshy land.

5. No proper silencer, extension of engine exhaust is given by using a simple pipe.

6. 5L self made oil tank which is not up to the mark

 

Rasikbhai Rathod
    Bullet santi model-1

Advantages 

1. Good quality of fabrication.

2. Royal Bullet silencer with some modifications.

3. 6.00-12 Traction tyre, Covered with half bonnet.

4. Greaves Engine Diesel Tank used as oil tank. As compared to first model which was hand made.

 

Disadvantages

1. Chain and sprocket fitted in a housing as it protects it from dust and damage.

2. Manual liftingcauses more effort to farmer

3. Greaves Engine Diesel Tank used as oil tank

4. Increase in weight i.e.400 Kg approx

5. Less horse power i.e.7.5hp Greaves , 3600 RPM

6. No depth or draft control system implemented.


    Bullet santi model-2

Advantages

1. More power as compared to second model,10.5hp Greaves engine, 3000 RPM Rest same as second model.

2. Less Fuel consumption.

3. Bullet santi is cost effective with respect to tractor.

 

Disadvantages

1. More weight as compared to 1st model i.e.400 Kg Approx.

2. No wheel track adjustment.

3. No ground clearance adjuster.

4. Instrument gauges such as transmission oil temperature, pressure are not implemented.

 

Hasmukhbhai Chauhan
    Bullet santi model-1

Advantages

1. Much less weight as compared to other models i.e.280 Kg.

2. Gearbox of Maruti 800 (1-2-3-4&Reverse) coupled with a propeller shaft.

3. Auto rickshaw (Brand: GC 1000 or Atul Shakti) spring suspension which further decreases maintenance as compared to telescopic suspension.

4. Hydraulic pump, which is used has the capacity of lifting 2 tons, Lorven control valve.

5. Uses a different kind of suspension that is used in auto rickshaws. Modification at the point of origin of gear shaft.

 

Disadvantages

1. Low power as compared to first model i.e7.5hp Greaves engine, 3600 RPM.

2. No proper silencer, extension of engine exhaust is given by using a simple pipe.

3. No wheel track adjustment.

4. No ground clearance adjuster.

    

Bullet santi model-2

Advantages

1. More powerful as compared to 4th model i.e.10.5hp Greaves engine, 3000 RPM.

2. Differential of Maruti Omni which is less bulky than ambassador.

3. GC 1000 or Atul Shakti spring suspension.

4. Modification at the point of origin of gear shaft which gives prescribed torque in field.

 

Disadvantages

1. No proper silencer, Extension of engine exhaust is given by using a simple pipe.

2. Gearbox of Maruti 800 (1,2,3,4,R)(1-2-3-4&Reverse) coupled with chain & sprocket in which breakage of chain can be a problem.

3. Stability problem which driving.

 

Rasikbhai Sidhpura

Advantages

1. Jeep Gearbox With A Small Spur Gearbox, Which Is With A Shaft Mat And Acts Like A Pto.

2. Hydraulic Pump Having Capacity Of Lifting 2 Tons, Alex Control Valve With Safety Valve.

 

Disadvantges

1. Neither Silencer Nor The Exhaust Pipe Is Present Which Again Increases Emission.

2. Telescopic Suspension (Used In Chhakda) (Brand Avni) Can’T Be Used In Field. As In Marshy Land, Since Rear Wheels Are Sufficient For Shock Absorbing. It Will Increase Initial Cost As Well As Maintenance Cost.

3. Hitching Of Implement Is Quite Complicated.

 

Mistry Babubhai Makwana

Advantages

1. Hydraulic Pump Having Capacity Of Lifting 2 Tones, Alex Control Valve With Safety Valve.

2. Ms 2 Inch X 2 Inch In C Channel Chassis Light In Weight.

 

Disadvantages 

1. No Silencer Or Exhaust Pipe Which Increases Emissions.

2. No Draft Control Implemented.

3. Less Ergonomic Feature.

 

Mansukh Davda

Advantages

1. Royal Bullet Silencer With Some Modification Which Reduces Emissions.

2. Round Chassis Avoids Crop Damage, Also Requires Less Welding. Components Are Well Spaced.

3. Wheel Track Is Adjustable.

4. All Demerits In 7Th And 8Th Model Are Repeated.

 

Disadvantages

1. Stability Problem.

2. Power Train And Body Vibrations.

3. Less Torque Induced.

 

Vallabhbhai kareliya

Advantages

1. Round Chassis Avoids Crop Damage. Also Requires Less Welding. Components Are Well Spaced.

2. Provided With Wheel Track Adjustment.

3. Ms 2 Inch X 2 Inch C Channel & Front Curved Chassis.

 

Disadvantages

1. No Proper Silencer, Extension Of Engine Exhaust Is Given By Using A Simple Pipe.

2. Maruti Omni With Chain & Sprocket Attachment Increases Chances Of Breakage.

For Questions /  Contact us at summerschool@sristi.org

Society for Research and Initiatives for Sustainable Technologies and Institutions (SRISTI)

Address: AES Boys Hostel Campus, Near Gujarat University Library & SBI Bank, Navrangpura, Ahmedabad-380 009, Gujarat, India.

Phone: 079-27913293, 27912792,

Email: info@sristi.org