[karthik123]

Hello again!

Picking up from where I started four years from today ( http://www.team-bhp.com/forum/techni...-we-built.html)

My intention in writing this thread is to put together and share the life changing experience of building an automobile. The child is grown, but the dream isn't gone.

Introduction: Baja SAE ( Society of Automotive Engineers) India is an intercollegiate competition that is held at NATRAX, Pithampur every year, the event is sponsored by M&M. It is held under the aegis of SAE INTERNATIONAL which hosts similar competitions around the world (US,Korea, Brazil, South Africa etc.). The event requires student teams to design and fabricate an all-terrain vehicle to compete in various events.
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The teams must adhere to a rule book that is prescribed by the event organizers, which consists of several regulations that the teams must follow, the engine is made common (a Briggs and Startton 10hp engine.). The essence of the competition is to build a faster car by making it lighter and reliable to last the endurance race which is of 4 hours on the final day of the event.
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Technical: The vehicle is powered by a 10bhp B&S engine, coupled to a Mahindra Alfa four speed gearbox. The frame is a space tubular chassis fabricated from AISI 4130. Most of the components were machined out of AL 6351 t6 aluminum alloy to decrease weight. The vehicle was first idealized on paper and modeled in solidworks. Crash forces, bump forces, roll over etc were simulated and the material was optimized using ANSYS. The suspension was tuned by simulating the vehicle behavior in Lotus Suspension Analyzer. The vehicle has 11" of travel in the front using a double wishbone suspension and 8" of travel in the rear using a semi trailing arm suspension. The pedal assembly was completely fabricated on the floor (Organ Pedals) so that it could collapse rather than intruding the leg space of the driver. We've designed a collapsible steering column assembly, using a nylon shear pin whose diameter is calculated to shear at a pre-determined load to collapse in a telescopic column to prevent the impalement of the driver. All the welds were tested using NDT methods like Dye penetration. It is equipped with a 3-point harness and arm restraints. The buggy has hydraulic brakes that can lock all the four wheels when the brake pedal is jammed. It is also equipped with a electronic speedometer and Odometer and two kill switches. Weight: 270Kg (with all fluids, excluding driver.)

Journey:Working in a team of like minded people we set out to enter this competition, only this time the intention wasn't enough.We started with humble beginnings with just four people, talking about cars. The idea spread, we had a team! The first 3 months were very hard for us, we knew about cars but we didn't know exactly how to make them, so we had to hit the books.

Miliken&Miliken, Carol Smith, Thomas Gillespie became our gurus and Solid works, Ansys, Lotus Suspension, Adams took a hard time to get used to. Endless hours of internet research. We didn't read so many articles this year as compared to our rest 3 years of engineering education.

It was a grueling month for us with designs changing every day, something we thought was perfect was decided to be a waste in no time, trying to find just that perfect design that would work for us. Finally we came up with a best plan that will become our guide for fabrication.

The team left for Bangalore, thrilled and scared at the same time, we didn't know what will happen, we put a smile on the panels face. Virtual results declared,we qualified for the BAJA SAE India 2014!

Overjoyed but not carried away, we got to work, learning welding(this time TIG welding), profiling and everything else.

Months passed into the fabrication phase, we felt the heat of the competition. The vehicle had many problems, camber changes, suspension alignment, power train coupling, everything made us cry for help. Having already used OEM parts in previous projects, we thought of eliminating the usage as much as we could, this meant that anything that could be done by us, has to be done by us.We designed and manufactured the uprights (steering knuckle), hubs, brake rotors, pedal assembly, steering column among other components.


Finally when we could drive it, overjoyed, we knew the feeling of being content. We learnt the importance of friendship, team work, and team members. We had fights, we had sad moments, we had happy moments, we had moments where we jumped and ran around like mad people not minding anybody.

One year of effort just for 3 days of incredible BAJA- the true essence of engineering. We designed, analyzed, fabricated, and tested. We are thankful for the engineering maturity and patience that the competition teaches us. It is a small glimpse into the life of a professional racing team.

The End: We've cleared all the technical inspections and cleared for the race, our dream ended when we had a collision on the rear end by another vehicle three hours into the race, we didn't win anything, but we are mighty satisfied as a team to have done this. I will cherish these memories for my life! I only wish I had a chance to work again, but heck I'm graduating.

Oh, it's called the NEBULOUS 1 or the S10RERWDSDV (Single Cylinder 10hp Rear Engined Rear Wheel Drive Shaft Driven Vehicle)

This is the story of all the teams that compete in these events.

PS: the name of this thread is borrowed from an amazing book by ROD KOCH that can be found here.

Attached are some images of designs, fabrication, testing and event.

Thank you for reading!

[mashmash]

Wow that is an amazing achievement to see a child grow from a sheet of metal to a structure, to make noise and move. Congratulations.

[autoholic]

Please educate me.

Why are there only dampers/shockers on the vehicle without springs???

[Rehaan]

Awesome story - and the end result looks fab too. Love the black and aluminum colour combination!

Originally Posted by karthik123

Picking up from where I started four years from today

Sharing a picture here from the "4 years ago" thread you linked to

Originally Posted by karthik123

It is equipped with a 3-point harness and arm restraints.

I was quite surprised reading this!! I'd imagine BAJA would have a much higher chance of roll-over (than FSAE for example - which required 4/5 point). Is it just the Indian version's rules that allows a 3-point belt?

Originally Posted by karthik123

We started with humble beginnings with just four people, talking about cars. The idea spread, we had a team!

Sounds kinda like Team-BHP

Originally Posted by karthik123

Having already used OEM parts in previous projects, we thought of eliminating the usage as much as we could, this meant that anything that could be done by us, has to be done by us.We designed and manufactured the uprights (steering knuckle), hubs, brake rotors, pedal assembly, steering column among other components.

What did you guys spend the most time on? What was the hardest? And what had to be re-done the most times?

Originally Posted by karthik123

Oh, it's called ... the S10RERWDSDV

You sure do have a penchant for these names!!

cya
R

[karthik123]

Originally Posted by autoholic

Please educate me.

Why are there only dampers/shockers on the vehicle without springs???

Hi, they aren't just dampers, they are called air-springs, extensively used in off-road motorsport in the US. You can learn more about them here. The reason we chose them was their adjustability, the ability to tune the ride qualities according to driving style or terrain.

Originally Posted by Rehaan

Awesome story - and the end result looks fab too. Love the black and aluminum colour combination!

I was quite surprised reading this!! I'd imagine BAJA would have a much higher chance of roll-over (than FSAE for example - which required 4/5 point). Is it just the Indian version's rules that allows a 3-point belt?

What did you guys spend the most time on? What was the hardest? And what had to be re-done the most times?

Thank you, that's actually candy purple, it looks like black due to some really amateur photography/lighting :-D

Actually about the seatbelt, I'm sorry I didn't recollect clearly. It is a 5-point harness, thanks for pointing it out.

We didn't struggle in design as much as we have in fabrication. Even sourcing, storage and retrieving parts was a hassle, specially with graded bolts meant for specific purposes.

On a more serious note, we struggled in the design of rear suspension and powertrain, we had troubles with axle plunge out because the gearbox didn't accommodate the travel of the suspension. This took a lot of time and trail runs to get right. Getting the shaft angles from the gearbox needed lowering the engine/gb setup several times.But these problems were sorted during testing, the biggest problem we faced from the beginning was the brakes. We ran a dual master cylinder setup with a brake bias bar, also fabrication of our own brake rotors meant the brakes weren't locking completely, this required endless hours of bleeding till the competition, changing disc material/ surface roughness to increase efficiency, then we had a leak near the hydraulic brake switch( this happened in Indore) because of which we didn't clear the brake test in the first attempt as the air bubbles were getting in the pipes, we had 30mins to fix it, some m-seal along with 15 people taking chances to blow dry it and the most intensive bleeding ever done in 30mins ensured we cleared the test

[ilangop]

Originally Posted by karthik123

Attachment 1274650

Nice work guys, keep it up. How much torque does the engine generate? Does the engine have enough power to climb the stairs or was this pic taken while getting down the stairs?

[amartyasg]

I was there in Baja India 2014. Team No. 113, Team Manipal Racing. Great to see something very familiar to me on this forum. I know exactly how you feel seeing the car take shape virtually, and then a few months later see it sitting in front of you.
Nice car, by the way. Its sad to hear that your endurance ended in a collision. We too took hits from the back, but luckily the car kept going until about 10 minutes from the end.

[karthik123]

Originally Posted by ilangop

Nice work guys, keep it up. How much torque does the engine generate? Does the engine have enough power to climb the stairs or was this pic taken while getting down the stairs?

It makes 19.6 N-m @ 2800 rpm. The engine has enough power to climb the stairs !