In putting this project together there were certainly no ‘client clinics’ or ‘focus groups’, nor is it a ‘game changer’ or a ‘unique driving experience’! Start is simply what I want from a ‘fun’ car.
- Put the 'market' back to where it was 20 years ago; affordable for many
- Get away from the £4-5000 starter kits
- Offer a 'basis', for people to do what they want
- Offer the option of a 'self jigging' tube pack
- Be different
Everything has been done before. Put together by 'cherry picking' what I think should work together, and I do not claim any 'origibality' with anything.
The intention is to offer ‘fun car’ ownership; it will be a single seat reverse trike, have decent performance and can be put on the road at a reasonable price. The keyword throughout the design is 'Simplicity'; simple to build and to maintain. It will be the least of everything.
It’s not new, everything has been done before, it's just a matter of 'cherry picking' the right bits to incorporate!
I don’t think there is a big one as the car is self-restricting by being single seat, but it’s the same market where someone buys a motorbike for solo fun, or the person who buys a jetski.
Kit/component car costs have rocketed over the years so, using a simple chassis and easily available 'parts bin' components to keep completion costs to circa. £2500.
Many believe trikes are unstable. The design solution is where you put the single wheel and the wheelbase.
When any vehicle corners, the majority of weight is transferred to the outside front wheel, in this respect a reverse trike, with two wheels up front, is just the same as a four wheeler, and as the single rear wheel experiences no weight transfer, the vehicle remains stable. Too short a wheelbase and a trike becomes very unstable.
Pedals will be behind the front axle line and a crash structure in front of them.
Modern performance cars seem to need high speed to thrill; not our intention. This trike will be open, light, and quick enough; the driving experience coming from decent cornering and going up and down the gears.
WHY THREE WHEELS
A good three-wheeler will blend the open-air thrill of a motorcycle with the stability of a car.
Overall, reverse trikes have
- 30% less polar movement for better handling
- 25% lower rolling resistance, for lower energy consumption
- Fewer parts, for a quicker, cheaper, lighter build
- No differential, so the complexity of the rear end is reduced
Also, reverse trikes do not need the torsional strength as a four wheeler
DESIGN CRITERIA (in no particular order)
- The least possible to do the job
- Use proven, understandable and practical technology
- Integrate the design - let one part do the work of two
- As light as possible - each part should be just strong enough
- As small as possible on the outside for a lower frontal area
- Keep it easy to build, servicing and maintain
- Self jigging' chassis (no tooling, or jigs, required for construction)
- Single seat
- A minimum of comfort
- Minimum ground clearance - to minimize air flow under the car
- Slightly raked underside - to create low pressure under the car
- Minimum weight - for acceleration, braking
- Custom, self jigging' chassis so no tooling, or jigs, are required during construction
- Use easily available, manufacturers 'parts bin', components
- No 'extras'; anything not making it stop, go, or turn, will not be there
- Aerodynamically clean - for less drag
- Pointy front - to minimize frontal pressure build up
- Decent power - for acceleration
- Good brakes - for deceleration
Drawbacks (there always are!)
- No heater - neither does a motorbike
- No weather protection - there will be a small screen
- Heavier than a motorbike so performance is reduced
- Not as streamlined as a bike so performance reduced
- No storage - fit bike panniers
- No passengers - most car journeys are single occupancy
Adding 'tabs and slots' to joining components drastically reduce the amount of time and effort required to build an accurate chassis. Used together they avoid the need to 'layout' and remove the need for jigs and other sub-assemblies. The benefits are immediate and simplify construction.
The choice of donor is down to the customer.
Whichever bike, the front forks and top yoke are removed along with the hand controls, fairing, headlight and instruments.
The bike is then mounted to the rollover bar using the headstock and bottom yoke, two links secure the bottom front of the frame to the chassis, and side links from the chassis to the bike sides provide lateral rigidity.
Using a bike engine has pros and cons:
- Highly tuned car engines are expensive: a large motorcycle engine is a lot cheaper than a car engine of equivalent power.
- Sequential gearbox for a much simpler gear change mechanism
- Lack of low end torque
- No reverse gear
- Working life is reduced as it has to move more weight than designed for
- Clutch slip: a clutch designed to move 200 kilos, through a small tyre contact patch, is now moving 300+ kilos- The clutch will feel much lighter and engine reaction is sharper as there is no large flywheel mass spinning. Maybe heaver clutch springs to replace the light duty ones.
- Oil surge: bikes lean into corners, cars don't! When accelerating, braking and cornering, oil will move away from the pump pick up, possibly starving the engine of oil. The solution for oil surge is to baffle the sump.
Trikes do not need the torsional strength of a four wheeler.
The chassis will be a simple four-tube frame, based on two continuous beams, one either side.
To manufacture, the chassis sides are built flat, then 'self jig' as the two 'ladders' are joined together by cross pieces.
Adding the dash, forward stays and roll hoop completes the chassis.
Aluminum panels will be added to increase chassis rigidity.
Simple double A-arms with single spring/shock absorber.
Mr Suzuki/Honda/Kawasaki spent millions of Yen designing their bike so the donor’s rear suspension.
The Morgan three wheeler showed that you can generate high cornering speeds on narrow tires, and motorbike tyres have a minimal frontal area and rolling resistance, but it's important to get the tyre contact patch to match the weight distribution.
Limitations, using a bike tyre, will probably be wheelspin, due to the smaller contact patch, and high wear!
The bike cooling system will remain standard, although there will be a problem as the engine is away from it usual, open environment. There will be a generous, ducted, air flow to any radiator or, if air cooled, to the fins, especially where the exhaust exits.
A small thermostatic fan will be fitted to operate when the car is stationary.
The bike’s gauges and handlebar switches are extended forward to the dashboard. They come complete with the loom, are already calibrated and some newer bikes have fuel injection fault codes built in.
The only modifications needed to the standard bike loom are extensions to the lighting and dashboard.
The bike’s clutch, gearchange, braking and throttle controls using the standard cables or rod linkages are routed to the car-type pedal box via additional rod links.
Note: Never forget to earth the side stand switch and check for any other ‘safety’ cut out switches.
Pedals will be mounted on a single cross rail, then onto an adjust-a-rail, dragster style. Remove a couple of bolts and set the pedals where the driver is most comfortable. This is good if more than one person drives the car or adds to car resale value. An adjust-a-rail pedal set is easily moved to make any driver more comfortable.
There will be no wind tunnel testing or scale models, form will follow function. Body will be minimalistic, the shape will be dictated by the mechanicals, as the body will be a shrink wrapped envelope.
A 'start' button; what else?
There will be some 'economical' way to manufacture them to be 100% green.
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