[Teri_TX]

Hi everyone,

I recently joined and have been lurking a while before making a fool of myself by posting :-)

I stumbled on to this site via a stumble on to Craig Vetter's site after stumbling on another site ... I forget what I was orginally looking for. That's the beauty of serendipity! Anyway, I'm a retired engineer (mechanical and electrical) with even more time now to ponder things. I have never had a motorcycle or ridden one (except once on my brother's dirt bike many moons ago) but I'm considering one (Honda CBR250R is my current choice) for high FE so I can putter around and explore the countryside. Having weather protection would extend the utility of the motorcycle instead of just being a joy riding toy.

Allert Jacob's velomobile is probably the most documented successful and beautiful aero bodied motorcycle/scooter (sorry Craig Vetter !) to date (in my opinion). He reports that side winds have minimal effects on the handling and this is without a long tail. After reading about many of the other similar projects I started wondering why his aeroshell is least affected by side winds.

Others have mentioned in passing that the side forces from side winds is from the lateral lift forces after a vector analysis of the apparent wind direction. This got to me to thinking of why and how minimize the lateral forces. Craig Vetter's "last Vetter Streamliner" had door fairing temporarily until he decided the side gusts were too much with them. He is also a veteran motorcyclist and probably prefers the open feeling of not having door fairings anyway.

The above ramblings got me to thinking that maybe the lateral lift is the real problem and I started Googling about wings and various lift and spoiler devices. Today, I stumbled across a "spoiler" type device called a stall strip which is just a simple triangular piece of metal (usually) placed at the stagnation point of the wing root to improve stall behavior. Even the U2 spy plane has a retractable stall strip to assist in landing since it simply just wants to keep flying which I found in my Googling..

After reading about "stall strips" I looked again at Allert's aeroshell to verify something I had just thought was simply a "styling" look he placed on the sides. The swoopy creases and resultant slight concavity probably cause any lateral lift to be ruined or minimized at least. I wonder if Allert deliberately put them there for aero reasons or that he just thought they "looked good". Anyone have an email address for Allert Jacob or other means to relay this question to him? Theo22? I'll PM him.

Back to Vetter's streamliner, I wonder if a stall strip or even a low vertical fence on the centerline of the nose section would serve a similar purpose to disturb the low pressure side airflow in a side wind gust condition and yet not have any perceptible parasitic drag in the forward direction? I hope Craig Vetter reads this or I may have to email him directly if he doesn't respond to this post.

On another thought, I did a search of the archives for "DIY wind tunnels" and many replies were rather negative, pointing out the Reynold numbers etc. The original posters were usually asking to determine Cd's and such to "compute" forces on their "finished" project. I was wondering if instead of the utility in studying flow conditions and "relative" forces between different designs. The operative term is "relative". I have a 42" shop fan which might be used as the fan for a modest wind tunnel. Of course, where I live, the wind blows rather hard most of the time from the south and I could probably just set up models outside.

Sorry for lengthy post and look forward to an intelligent discussion.

-- Teri