Tripster

Several years ago I became involved with the late Rob Brock’s project to create a four-wheeled, pedal powered ‘platform’ for a number of utilitarian configurations. This concept evolved into the Brox, brilliantly designed by HighPath Engineering; David Wrath-Sharman in partnership with Chris Bell.

At that time I was living several miles from anywhere in particular and surviving on a meagre income generously provided entirely by the state. Rob gave me sufficient damaged components for me to knock-up a Brox of my own, which proved invaluable, particularly on sorties to collect firewood in the surrounding forests.

LoadedBrox

There was a mystery on the day this photo was taken, that you may like to hear. The previous evening I had set about felling the tree. I could see, 50ft above me, it had more weight on one side. That would make it very difficult to drop and not hung on an adjacent tree. The legitimate feller would have a chain round it with a tractor at the other end to pull it in the desired direction. No such luxuries for me, so I cut a gob in the direction I wanted it to fall, but when I put the back-cut in, you can guess what happened; the tree began to lean in the direction it wanted to, and pinched the guide bar of my chainsaw as firmly as you could ever imagine.

Not to worry, both guidebar and chain were well-worn, so I detached them from the chainsaw body. As darkness fell I sat and looked at the tree, musing strategies for getting it onto the ground, methods that would have Health & Safety in a tiz, before going home.

Being winter, I didn’t have to get up too early to fit the new guidebar and chain, and be back by the tree not long after first light.

The old guidebar and had chain gone! I kid you not! No sign of wedges having been used, not that they would have helped much, and the tree was exactly as I had left it. From the size of the logs you can see it was a pretty big tree, a lot of weight holding the guidebar and chain firmly – and you can see that I did eventually get it down. I was very concerned that apparently someone knew what I was up to, but no-one disturbed me.

Getting the Brox as close as possible to the tree to be felled, and then transporting the booty home involved driving it over demanding terrain, often with a very heavy load, like above.  I found that having a basically stable machine meant I could easily make manoeuvres whilst almost stationary, but without the effort required to maintain balance; I could stop at almost any moment to have a rest. Also, I could climb slopes that would be difficult on a bicycle, by a technique of using only the power phase of the cranks combined with the brakes in a stop-start motion; it was slow but sure. Since this activity was completely illegal, stealth was a virtue. Exhausting though this activity was, I enjoyed overcoming those challenges immensely.

TripsterGraphic-copy

So much so that I began to conceive of a specialist off-road recumbent which could be considered a ‘tractor unit’ in the context of load-carrying, by adding a trailer. Thus, without a trailer, it would become a vehicle for all-terrain adventures.

Experience showed me that the principle design challenges could be reduced to the following, each requiring the adjective ‘very’, or as people prefer saying nowadays ‘incredibly’:

– good traction
– tight turning circle
– short wheelbase
– simple construction
– wide-range gear ratios

TurningCircle-copy

And three conflicting aspects:

– good ground clearance
– low centre of mass
– narrow track width

These aspects conflict because you can’t have a low centre of mass if you also want good ground clearance and, to overcome the problems caused by a high centre of mass, you’d go for a wide track width. However, a narrow track width is necessary to get through narrow gaps.

TripsterFrontRear

Just like the Landseer, this machine is not intended for speed. Forget speed, don’t even think about it. Think more along the lines of going for a challenging hike while sitting down.

TripsterSide

TripsterAbove

I call it the Tripster.

This off-road recumbent idea remained just that, an idea. Somewhere amongst my stuff are a number of sketches, none of which really nailed the practical possibilities of building something which, in my circumstances, will probably remain a fantasy. Recently, though, my work developing the Landseer, combined with my learning how to use CAD, means I can bring this concept just a little closer to reality.

 

 

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