Thursday, January 14, 2010

Off-Road Tandem Bike
Strategic Design Elements:
Compact-ish – to fit in box, but can expand upon assembly
Easy Assembly – some mechanical joining on competition day
Lightweight Materials – aluminum, cro-molly : ) etc.
Stability - wide wheel base, 3 to 4 wheels, good suspension, low center of gravity, thick tires with heavy tread
High Torque – large tires with heavy tread, recumbent seating with long pedal throw, standing & stepping on long lever throw
Wheelchair Option – to accommodate for friends with spinal cord injuries, and because using your hands & arms is fun!!!

Design Idea:
A hand-drawn sketch will be coming soon! For now, the idea is a FWD Recumbent Trike with RWD Stepper. Here’s the design break-down:
FRONT WHEEL (CHAIN) DRIVE, DELTA RECUMBENT TRIKE
Stability
- 3 wheels
- wide wheel base created by 2 non-turning rear wheels
- low center of gravity, recumbent = low to ground
- thick tires with heavy tread
- good suspension (option for complete-frame-suspension … See Resources!!!)
High Torque
- high torque - bent knee to stretched leg pedaling, long pedal throw
- large tires with heavy tread
 Wheelchair Option
-  2 rear non-turning wheelchair wheels
Additional Info:
-    A larger front wheel for better turning and utilization of torque from recumbent power
(think “Big Wheels” like when you were a kid…)
-    Front Driver controls steering and all-wheel-braking system
-    Free-wheel pedaling 
Resources:
Front Wheel Drive Trikes
Full-frame suspension FWD Trike *PLANS* - SEE “Tadpole Plans.pdf”


REAR WHEELS (CHAIN) DRIVE, STEPPER
Compact
- Only pedals & standing bar added to recumbent design
Easy Assembly
- Only pedals & standing bar, NO SEAT OR ADDITIONAL FRAME! :  )
Stability
- Near wide wheel base at back
- Low Center of Gravity… person can duck down when necessary
- Large step-panels for feet
- Rigid standing bar to hang onto
High Torque
- bent knee to stretched leg stepping
- can use full body weight into each step
Additional Info
- Free-wheel pedaling
- Wheel base large enough for stability, but compact enough for efficient wheelchair use

Resources:
The “Randy Ross 3G Stepper” (2:13-2:20) looks like bike pedals are round roller bars (moving backward?), and foot boards made of pressed-ply Canadian Maple with metal track/roller bar-guide underneath
Ross Concept- ion Interview
Stepper Construction Manual
Also an idea,
Elliptical idea
EliptiGo Glide Bike

3 comments:

  1. Wow! Check out the suspension/self-centering turning in action :)

    http://www.youtube.com/watch?v=fjbIAVladHs&feature=related

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  2. also check out:

    http://www.youtube.com/watch?v=sywPW1K3I9E

    http://www.youtube.com/watch?v=mcjj6OuexSo&feature=PlayList&p=0F0DF05C0202025B&index=0&playnext=1

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  3. TTWs or "Tilting Three Wheelers" may be an issue if we decide to use a "Stepper" on the back half of the vehicle.

    Check out how simple the frame of FWD - Tiago is.
    http://www.fastfwd.nl/index.php?id=30
    We will probably need front wheel steering if we are to have a "Stepper" on the back.

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