So firstly I know I haven't fully finished my current project: https://endless-sphere.com/forums/viewtopic.php?f=34&t=76189
But that was always a compromise to meet a specific set of requirements:
2 seater able to compete in motorkhana and khanacross. This means the frame and roll cage had to be significantly bigger and heavier, thus the motor and batteries also had to be bigger and heavier.
As a result I was always aware it would struggle to be competetive in both competitions.
I am starting to gather ideas for phase 2. This is probably a few years off but I want to plan it out and build it over a slightly longer period (not 11 months like the current car) The requirements would be significantly different:
A small and light as possible. Single seater. Just a single hoop for the roll over protection.
Considering my current project came in at 530KG I am thinking I can bring Phase 2 in at around 230KG.
The weight of the current car is approximately:
Motor 60KG
Seats 20KG
Frame 200KG
Rollcage 60KG
Controller 20KG
brakes, hubs, suspension, wheels and tyres 60KG
Batteries 70KG
Cables 15KG
Elliminate the gearbox -50KG
Single seat -10KG
Reduce the motor weight -40KG
Reduce the frame weight -120KG
Reduce the roll cage weight -40KG
Reduce the batteries -30KG
Reduce the controller - 5KG
Reduce the Cables -10KG
=approximately 230KG
To achieve this I am thinking of running two large hub motors (circa 5-7 KW each) on each of the front wheels. I am thinking of using the old style VW wheels because I think I could get them to mount on the hub motor effectively. I am not sure how I would run brakes but I guess I would get some sort of disc machined to fit alongside the hub motor. The wheels and tyres would need to be a compromise. Big enough to get some grip but not so big that they add stress to the motors and other components. I think 205s would be about the best.
The front frame is where most of the stress is. So it would continue to be steel. I would need to design a couple of primary members from front to rear to give the rear the torsional strength required. These primary members would somehow connect to the roll over protection and rear suspension. But otherwise the rear half of the car would be alloy and composite materials. Because I am planning on using hub motors I no longer need the space in the front for the motor, gearbox and driveshafts. So I will be able to reduce the structure surrounding these items and be more conservative with my suspension design and weight.
What are the biggest reliable hub motors available?
What sort of controller does everyone recommend to run these sort of motors?
I would also be mounting the batteries in the front, reducing the cable weight required and placing a larger percentage of the weight on the front wheels.
I would have a sensor on the steering so as you turn the wheel it sends less power to the inside wheel. Or maybe even a sensor on the dual handbrakes so it cuts the power to the inside wheel while continuing to power the outside wheel to drive the car around the obstacle.
I would keep my current car so I could still compete in the Khanacross. Running the new car in Khanacross would be too unstable due to the reduced wheelbase plus the impact protection is reduced.
Any thoughts
But that was always a compromise to meet a specific set of requirements:
2 seater able to compete in motorkhana and khanacross. This means the frame and roll cage had to be significantly bigger and heavier, thus the motor and batteries also had to be bigger and heavier.
As a result I was always aware it would struggle to be competetive in both competitions.
I am starting to gather ideas for phase 2. This is probably a few years off but I want to plan it out and build it over a slightly longer period (not 11 months like the current car) The requirements would be significantly different:
A small and light as possible. Single seater. Just a single hoop for the roll over protection.
Considering my current project came in at 530KG I am thinking I can bring Phase 2 in at around 230KG.
The weight of the current car is approximately:
Motor 60KG
Seats 20KG
Frame 200KG
Rollcage 60KG
Controller 20KG
brakes, hubs, suspension, wheels and tyres 60KG
Batteries 70KG
Cables 15KG
Elliminate the gearbox -50KG
Single seat -10KG
Reduce the motor weight -40KG
Reduce the frame weight -120KG
Reduce the roll cage weight -40KG
Reduce the batteries -30KG
Reduce the controller - 5KG
Reduce the Cables -10KG
=approximately 230KG
To achieve this I am thinking of running two large hub motors (circa 5-7 KW each) on each of the front wheels. I am thinking of using the old style VW wheels because I think I could get them to mount on the hub motor effectively. I am not sure how I would run brakes but I guess I would get some sort of disc machined to fit alongside the hub motor. The wheels and tyres would need to be a compromise. Big enough to get some grip but not so big that they add stress to the motors and other components. I think 205s would be about the best.
The front frame is where most of the stress is. So it would continue to be steel. I would need to design a couple of primary members from front to rear to give the rear the torsional strength required. These primary members would somehow connect to the roll over protection and rear suspension. But otherwise the rear half of the car would be alloy and composite materials. Because I am planning on using hub motors I no longer need the space in the front for the motor, gearbox and driveshafts. So I will be able to reduce the structure surrounding these items and be more conservative with my suspension design and weight.
What are the biggest reliable hub motors available?
What sort of controller does everyone recommend to run these sort of motors?
I would also be mounting the batteries in the front, reducing the cable weight required and placing a larger percentage of the weight on the front wheels.
I would have a sensor on the steering so as you turn the wheel it sends less power to the inside wheel. Or maybe even a sensor on the dual handbrakes so it cuts the power to the inside wheel while continuing to power the outside wheel to drive the car around the obstacle.
I would keep my current car so I could still compete in the Khanacross. Running the new car in Khanacross would be too unstable due to the reduced wheelbase plus the impact protection is reduced.
Any thoughts