The Creeper Track Society is restoring a Citroën Kegresse P17E half-track vehicle. These fellows are carrying out the restoration in detail and documenting the process on their website: Creeper Track Society. I'm very interested in the process -- and the excellent skill and dedication of the team -- as they show their work restoring the boogies to building their own track replacement from scratch.
DARPA funded the development of this tracked vehicle -- Captive Air Amphibious Transporter (CAAT) -- which is part paddle wheeler and part tank. Designed to be an autonomous transport vehicle in land and water, this vehicle seems to take the best qualities of the track tread and make it work in these two environments.
Now, I know this is cool and all, but it is also a patent fake, 'shopped', a photoshop composite image. This image of a 'Tracked Urban Mobility Scout" or TUMS appears to be someone's imagination exploring the idea of fitting a Mercedes Smart car with a German Military Weasel light tank.
A visitor to the site -- t00tie -- sent over a link to a very cool 3D printer model for plastic tracks.
The model is called "Moon Rover" created by emmett on the site Thingiverse. The track design is derived originally from a expanding bracelet and it utilizes the pliability of ABS with the natural flex of the deep inset hinges between each cleat to get a simple yet effective tread.
There have been a number of tracked recreation vehicle designs popping up lately pushing into an interesting area of hybrid conversions. Specifically, these are kits designed to convert an off-road motorcycle into a uniquely capable snow machine. There are many companies, however, Timbersled is a popular kit out here in the mountainous West Coast of Canada.
This innovative track design from Japan's Osaka University allow a vehicle to carry heavy weight and gain the advantage of multiple directions of travel.
The design uses interesting split track layout mounted on wheels they call omni-balls -- spherical balls split into two hemispheres -- as the drive mechanism for the track. It appears from the video that the drive shaft attaches to the front and rear of the track mechanism and this supports the weight of the vehicle and transmits power and control inputs to the track.
We have found an old 3 wheeled golf cart and rebuilt all the required parts to make it a reliable machine for this year's Burningman event.
This platform has a good gas motor, large electric starter/generator, and solid variable speed transmission. Next year, we plan to remove the rear wheels, extend the back, and add tracks.
It's hard to look too serious while riding a 3 wheel golf cart with red fun fir seats . . .
Given the constraints of managing steering and traction, Dave and I have settled on a tracked tricycle design similar to that used in WW2.
I saw this in the Globe and Mail and had to post it here:
I really like their concept and the simplicity of the design. Seems like they used a snowmobile track, cut in half down its length, and all the stock drive cogs and idler wheels. Bicycle pedals and frames welded on to a square tube chassis rounds out the package. I'm curious to know how well it works and to talk with these guys... If you're out there drop us a comment!
Found some smaller ATV track examples. Similar to the car previously posted, however, smaller. One attractive thing about this design from a human powered vehicle perspective is that we would no longer need to utilize the skid-steer method of turning, which is inefficient and difficult for a load capable track design. In this ATV example shown below, the tracks in front steer independently and the rear are fixed.
Found a belt on the McMaster-Carr website that may serve as a good rubber track for the project.
Notice the cab-forward position of the driver(s) who also pedal the vehicle. The mid section is two doubleseat benches positioned sideways for the passengers (tentative seating plan) and a gear section to the rear where the sketch shows a cooler and radio.
Dave Montie and Greg Montie's 8 wheeled ground following track concept.
A late night Lego session lead to the creation a number of possible track designs. This one ended up a likely candidate for our goals:
Each of the 8 wheels will be bicycle rims and each set of two wheels is joined by arms that themselves pivot to follow the irregularities of the terrain.
This is Greg Montie's concept of a high rolling efficiency track.
The idea is to have a single V-belt for low weight, and a high efficiency linear (smooth) roll motion. A chain of aluminium cleats are riveted to the V-belt to complete the track. The cleats wings are curved to the diameter of the pulley wheel. This makes for a smooth rolling surface for the pulleys to travel on.
The cleats are made from 0.032" (or 1/32") aluminium. This aids in weight reduction and allows for each cleat's connector tabs to flex while following the V-belt around the pulley wheel. The cleat wings are not very strong as they are cantilevered on either side of the V-belt. However, the strength is improved by the general curved shape of the cleat. Furthermore, each cleat wing is protected during its most loaded duration - directly under the pulley wheel that carries the majority of the vehicle weight. This is accomplished by welding drums on either side of the pulley wheel, of equal diameter, that directly support the cleat wings under load.
3D File can be found here: 09-09-25 Assembly
Here is a link to a very detailed R/C Tank website that discusses a variety of options for building tracks. Below are 7 methods illustrated:
Bicycle Chain Track
Here is our first post introducing the project.
Stage 1: Collect ideas and examples from the internet.
Stage 2: Design and document our own plan
Stage 3: Begin the build
Stage 4: Testing and revisions
Stage 5: Demonstration!