Jurgen,
A trike with tilting wheels takes the cornering loads in the plane of
the wheels, just like a bike. The spoked wheel is very strong in this
plane. A trike with vertical wheels takes the cornering load as a couple
between the hub and the rim, which tends to bend the wheel transversely
to the plane of the spokes. A spoked wheel is weak in this plane, though
how weak depends on the width of the hub and angularity of the spokes.
In addition, the Flevo-trike leaning arrangement lowers the centre of
gravity when the rider leans, making it difficult to bring the trike
upright after leaning over, without special handles, brakes, or springs.
Because it has a much lower roll centre, any leaning system which relies
on the paired wheels moving up and down reduces this effect
substantially (for a given sideways movement). Just draw the arcs: the
roll centre of the Flevo is at the rear-end pivot, but the roll centre
of a Tripendo or similar is at ground level, and the CoG is perhaps 20cm
above the seat. Henry's design goes even further, and allows the centre
of gravity to move sideways and even rise a little, making it much
easier to recover after leaning.
A Flevo-type mechanism for a tadpole trike would be complex anyway. It
would be a beam axle pivoting around the boom, with the wheels on
kingpins or other pivots at the two ends, and a steering mechanism to
work them. All the complication of suspension, with none of the
advantages. You can't simplify it by attaching the wheels to unhinged
stub-axles, and steering by pivoting the axle around a vertical pivot:
that is a viciously dangerous arrangement, known in this country as
"billy-cart steering".
George
On Tue, 2011-09-20 at 09:09 +0200, Jürgen Mages wrote:
Could s.o. please tell me what is the advantage of all these tilting
constructions over the relatively simple flevotrike Duschar-joint?
http://www.karstilo.net/hpv/fahrzeuge/flevo/flevo_230.jpg
http://www.karstilo.net/hpv/fahrzeuge/flevo/flevo_231.jpg
I have the feeling that all this is kind of over-engineered and only
leads to more weight and much more failure/wear problems in daily usage.
A friend of mine wants to build a replaceable flevotrike-like rear-end
for his python for commuting during the winter season. And like me he
prefers the simple solutions. I'll send you some photos, when it is working.
Jürgen.
