Open Source Car/Manufacturing Instructions: Difference between revisions
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=Design Rationale= | =Design Rationale= | ||
The basic requirements for the OS Car are: | |||
*Two passenger capacity | |||
*Ultra-high fuel economy (50+ MPG, city, 100+ MPG, highway) | |||
*Ultra-long range (1000+ miles) | |||
*Low Cost (less than $12,000) | |||
*Ease of Construction (1000 hours of construction time. Can be constructed by one person in 1000 hours with a vertical mill, band saw, disc sander, grinding wheel, air compressor, welder) | |||
*Reverse Trike Layout | |||
The [http://en.wikipedia.org/wiki/Three-wheeled_car#Two_front reverse trike] layout was chosen because it allows for side by side seating, an aerodynamic rain drop shaped body, and safe handling. A two-wheeled vehicle with tandem seats resembling a motorcycle would have less frontal area and probably less wind drag, but would simply not be practical to drive. A four-wheeled vehicle could be made with a rain drop shaped body, but would have extra drag from the two rear wheels which would protrude from the body. The reverse trike design may seem novel, but has been used successfully for over 100 years in cars from the [http://en.wikipedia.org/wiki/Egg_%28car%29 Egg] to the [http://www.aptera.com Aptera]. Other benefits to the reverse trike layout are lower weight and cost due to the obviation of one wheel and a differential. | |||
*Hybrid Hydraulic Powertrain | |||
In order to | |||
. . two-seat side by side | |||
After mulling over the objectives of ultra-high fuel efficiency, lost cost, and ease of construction, so far, the Open Source Car has shaped up to be a reverse trike with a steel tube frame and a hybrid hydraulic drivetrain. Although a reverse trike might seem like an unusual design, the the configuration is not new and has been used for multiple vehicles and Marcin and I determined it to be the best configuration that provides the ability to achieve the lowest wind drag possible on a stable platform. I also have to guess that the designers of the Aptera and Urbee had the same thinking when they decided on this configuration. In addition to low wind drag, low weight is a necessary attribute, so we opted for the tried and true steel space frame design. Most are by now familiar with hybrid electric vehicles such as the recently launched Chevy Volt, so why did we opt for a a hybrid hydraulic drivetrain? One reason is that it leverages hydraulic technology already developed for the LifeTrac. Other reasons are that it doesn't require either extremely heavy, but economical lead-acid batteries, or lightweight but very expensive lithium-ion or similar batteries and provides superior energy recovery during regenerative braking. | |||
=Conceptual Diagram= | =Conceptual Diagram= | ||
Revision as of 22:38, 15 May 2011
Design Rationale
The basic requirements for the OS Car are:
- Two passenger capacity
- Ultra-high fuel economy (50+ MPG, city, 100+ MPG, highway)
- Ultra-long range (1000+ miles)
- Low Cost (less than $12,000)
- Ease of Construction (1000 hours of construction time. Can be constructed by one person in 1000 hours with a vertical mill, band saw, disc sander, grinding wheel, air compressor, welder)
- Reverse Trike Layout
The reverse trike layout was chosen because it allows for side by side seating, an aerodynamic rain drop shaped body, and safe handling. A two-wheeled vehicle with tandem seats resembling a motorcycle would have less frontal area and probably less wind drag, but would simply not be practical to drive. A four-wheeled vehicle could be made with a rain drop shaped body, but would have extra drag from the two rear wheels which would protrude from the body. The reverse trike design may seem novel, but has been used successfully for over 100 years in cars from the Egg to the Aptera. Other benefits to the reverse trike layout are lower weight and cost due to the obviation of one wheel and a differential.
- Hybrid Hydraulic Powertrain
In order to
. . two-seat side by side
After mulling over the objectives of ultra-high fuel efficiency, lost cost, and ease of construction, so far, the Open Source Car has shaped up to be a reverse trike with a steel tube frame and a hybrid hydraulic drivetrain. Although a reverse trike might seem like an unusual design, the the configuration is not new and has been used for multiple vehicles and Marcin and I determined it to be the best configuration that provides the ability to achieve the lowest wind drag possible on a stable platform. I also have to guess that the designers of the Aptera and Urbee had the same thinking when they decided on this configuration. In addition to low wind drag, low weight is a necessary attribute, so we opted for the tried and true steel space frame design. Most are by now familiar with hybrid electric vehicles such as the recently launched Chevy Volt, so why did we opt for a a hybrid hydraulic drivetrain? One reason is that it leverages hydraulic technology already developed for the LifeTrac. Other reasons are that it doesn't require either extremely heavy, but economical lead-acid batteries, or lightweight but very expensive lithium-ion or similar batteries and provides superior energy recovery during regenerative braking.
Conceptual Diagram
Bill of Materials
(with weblinks to sources)
Demo Video
Demo Photos
Instructional Video
A to Z on the Fabrication
3D CAD files
Metal parts