From Open Source Ecology
- LifeTrac I - Articultated steering, 4 wheel drive, wheel chains, dedicated 55 hp diesel engine. Limited roll-over protection.
- LifeTrac_II - Began modular Power Cube design. Skid steering with tracks on rubber tires, 4 wheel drive, 2 modular engine units (Power Cubes), 54 hp total, front- and rear-end loaders included. 32 cu in hydraulic motors. Full roll-over protection as driver sits inside cab. Brakes are the hydraulic motors themselves.
- LifeTrac III - Same as II but one single (front-end) loader arm. 32 cu in hydraulic motors. Quick attach valves added. Issues with hydraulic motor to wheel couplers, where 6-spline agricultural shaft was used on each wheel.
- LifeTrac IV - Larger hydraulic motors (45 cu in) were used, and Modular Wheel Units were added. Quick connects added to hydraulic controls. Wheel shaft coupling issues solved. Entry is from the side.
- LifeTrac V - Began using LifeTrac Construction Set - 4"x4" square tubing, and increased modularity of construction. Modular Wheel Units continued. Returned to articulated steering and rear ground-higging pivot to separate 2 pivots for ease of fabrication. Introduced Bobcat Standard quick attach. Driver enters cab from front. Foot pedals + joystick valves were used for driving. Build for Our School at Blair Grocery urban farm.
- LifeTrac VI - Continued LifeTrac Construction Set. Modular Wheel Units are a robust design feature. Same design, but fixed the loader arm geometry. Used a single curl cylinder, but found that it makes it difficult to enter the cab. Issues with curl geometry. Need to simplify forearms. Reached 75 hp with 3 Power Cubes, such as 25 hp for wheel drive and 50 hp for 6' trencher.
- LifeTrac 7 - first tracked version.Continuing Tractor Construction Set with Bulldozer Development. Initial build of tracked tractors. Need for CNC torch table cutting of parts became evident - as making tracks by hand is too time consuming.
- LifeTrac v16 - Tracked tractor 2016 - This was designed purely as a simplified traction machine with 7000 lb of pull.
- LifeTrac 17.10 LifeTrac 17.10