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Solar leaning trike safety concerns

November 17, 2023 — BarryK

I have been discussing with Bart via email, safety concerns for a leaning trike with large solar panel on top. Some quotes from Bart:

when pivoting around and when going to the max., that the momentum of the top weight will kick your back wheel away. Then you end up with the bike on top and you trapped underneath it.
Your solar panel is not a big sail in the wind when it is turned flat. But that's a real problem when turning that panel sideways by leaning the bike.
Turning TOO much and you collapse under the own weight. .... one way or another: Getting a blast from the wind and you lie on the OUTSIDE the corner.

Yes, the momentum of weight up high is an issue. It is important that be minimized and the weight be as low as possible; preferably most below the axis of the wheels.

The wind, now that's a big concern. Lots of guys have added solar panels on top of bicycles, such as this one (image copied from here):

img1 windy conditions, an accident waiting to happen!

A recumbent bicycle with weight lower down may be an improvement, like this one (image copied from here):


...but on the otherhand, the recumbent position maybe means reduced ability to lean into a corner and retain balance. And of course, once the rider does lean, the solar panels become a sail.

A non-leaning trike keeps the solar panels horizontal, so less likely to behave as a sail. A leaning trike that relies totally on the rider's balance, is just like a bicycle; at the mercy of wind catching the tilted solar panels.

The earlier blog post described a leaning trike design with a single shock absorber. The advantage is simplicity; however, the downside is it relies totally on the rider's balance. The single-shock design is here: may be possible to introduce linkages from the steering to control the lean, but I have not discovered any practical way of doing it.

So, have returned to thinking about using two shock absorbers. The major advantages of this is that it can be locked to become a non-leaning trike if desired, and lean is controlled by linkage from the steering handles.

The go-kart suspension kit came with two 222mm shock absorbers, but I also bought a couple of 165mm shocks. This design is using the latter, as it is perhaps a bit neater, keeping the shocks mounted low-down:


...the two shocks are mounted at a common point called the "slider". If this slider is fixed in place, then the trike becomes non-leaning. The slider is attached to the "rod" and can slide along it. The intention is that the slide will be controlled by a linkage from the steering. In SolveSpace, pushing the slider along the rod, shows that leaning occurs:


...what possible downsides could there be for this design? Well, if a wheel hits a bump, there will be some kickback to the steering. That could be eliminated by a worm-gear drive linkage, but perhaps that is an overkill. A steering dampener could also be used, which is probably what I will do -- especially as one came with my trike.

Will it be difficult for the steering handles to slide the slider? If required, the linkages could provide some mechanical adavantage -- hmmm, which might also increase kickback.

An alternative is to use the original 222mm shocks that came with the go-kart front suspension kit. Then, the slider would be much higher:


...the almost 80 degree angle of shocks to slider would mean far less kickback to the steering.

Currently I am favouring the 165mm shocks. The 222mm shocks would mean the slider will be close to the rider's legs, not quite sure if too close.

Still haven't figured out the linkage from slider to the steering mechanism; kicking that can down the road.

Note, that second photo came from a fascinating web page:

EDIT 20231118:
This rod-and-slider design is continued in the next blog post:     

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