On 4/14/2017 6:10 PM, DougC wrote:
On 4/14/2017 3:48 PM, Frank Krygowski wrote:
On 4/14/2017 3:07 PM, DougC wrote:
On 4/14/2017 12:44 PM, wrote:
Interestingly enough a normal recumbent three wheeler is hard to get
on and off of perhaps the two wheelers are easier. But I can hardly
picture how you would get on and off of those streamlined ones.

But I think that they are a good idea. Now only would they give you
additional speed (a friend of mine who rides a standard two wheel
recumbent says that it's reasonably easy for him to ride at 40) but
also protection from the weather. Though the idea of windshield
wipers for fully enclosed models appears to be somewhat daunting.

Another thing is that you could have the streamliner painted a bright
color to make it a lot more visible than a non-covered version.

Velo windshields fog up on the inside surface, in the rain. The
windshields flip up and end up being just a visor in rainy weather.

The racing 2-wheel streamliners can't be used solo at all, since the
shells are totally enclosed and are taped shut after the rider is
inside.

So far the /only/ 2-wheel streamliners I've heard of being sold for
street use is the Peregrin-on-Birk
http://speedbikes.ch/en/peregrin-on-a-birk/
it is built very nice but the typical delivered price is $30K - $35K.

If you get a long-wheelbase recumbent and add a front fairing and
bodysock, you can get most of the aero gains of a hard shell with very
little cost and weight added. They look dorky but a decent job can add
5-7 mph to your flat-ground cruising speeds, assuming you have the
gearing for that.

I've wondered how stable those things are in gusting crosswinds. Any
idea?



Which thing are you asking about?

I was asking about two-wheel streamliners, like the Peregrin.

Years ago, we briefly had a club member who rode a recumbent, to which
he had fitted a homemade full fairing. It was a pretty crude,
square-edged thing made (I think) of Coroplast, and he was a somewhat
odd guy.

Anyway, as we rode together on one invitational ride I was chatting with
him, asking questions about his bike. When I asked "Do crosswinds have
a bad effect on it?" or something similar, he got a bit irritated and
didn't answer.

The aversion to crosswinds from passing vehicles seems to be the main
reason that nobody made a 2-wheel street streamliner until Speedbikes did.

Also with velos (that are almost always tadpole trikes): they're a lot
more popular in Euro-land, and they make it much more easy to ride
comfortably in sub-freezing weather. If the pavement has a bit of snow
or ice on it, you can still safely ride a trike but not with a
2-wheeler. So that is another reason.

The body socks tend to have some give with crosswinds. Most people who
go this route just buy the front fairing already made and add the body
sock rear. A few people have built their own front fairings just for
body sock use and it can work a lot better if it extends nearly down to
the ground.

Velomobiles and tadpole trikes do tend to have stability issues at
times. The current trend is to use tadpole trikes that have 33%/33%/33%
weight distribution per wheel. If they suffer a rear flat tire at high
speeds, slowing to a stop without crashing can be very challenging.
Velos (with their big noses that stick out well in front of the front
axles) seem to be particularly susceptible to this problem.
Delta-configuration trikes and velos don't seem to have it, but are
comparatively rare in the high-performance market.

The problem I've heard about with Deltas (vs. Tadpoles) is that if you
overcook the entrance to a turn, the tendency to brake and turn
simultaneously can get you in trouble, throwing weight too far forward
(so to speak). Also, I guess it's easier and cheaper to design two
wheel steering instead of two wheel power transmission, which requires a
differential gear.

--
- Frank Krygowski