Modern Vespa

i use a genuine vespa short screen which i find gives me a better top speed but at the cost of increased wind noise/helmet buffeting.....

i have often thought of putting 2 pieces of trim on the front of the screen in a "V" (or even curverd V ) to try to "split" the wind and send a fair proportion of it either side of the centreline of the screen and hopefully reduce the noise and buffeting........

am i mad?

No, just experimental. And maybe ingenious?

Do it, you might be onto something!

Do you know about the 'laminar lip'?
http://www.laminarlip.com/
Making a Flyscreen Extension Lip (In Pictures)

Is that what you're thinking of?


Harvey

was thinking more like "off vertical" strips of trim (windscreen wiper blade like dimensions) to "split" and send the wind past shoulders rather than head........

bottom of the "V" being middle of bottom of screen above headlight....

idea being wind would come up front of scooter, onto screen hit the bottom of the "V" and be deflected left and right......

think race cars do something like this........

OK, the lip is supposed to do the same thing, but by generating a high pressure air stream over your helmet



Harvey

i like the idea of the lip and i can sort of see how it works, i just thought the "splitters" would be an "easier" option as i don't really want a bulky "lip" or increase the height of the screen any.......

am i dreaming??!!

It hasn't been done before!
It's either mad or genius-
Only one way to find out which, give it a shot.


Harvey

I think the idea is pure genius.

It seems so obvious, but nobody has tried it yet. With that change, even I might consider fitting a windscreen.

Go fo it! And report back!

Mike

Could you do that wind test again, with the threads attached to the inner/lower screen?

Very interesting!

My guess is you'd end up increasing the turbulence, since you would be creating a vacuum for the air to fill.

This is a different idea I'm trying to keep an eye on. It looks weird, it sounds weird, but apparently it does work (from the small amount of Google translated text I've read) - The Windshield Propeller. This is a pdf I've converted to jpg for posting here. It's a crappy picture but hopefully you get the idea. The propeller is attached to the windshield and it creates smooth airflow behind it while keeping bugs off the rider (according to the translation) at the same time. It's not on the market yet, but I'd be first in line to try one!




Dave

mmmmm hadn't thought of turbulance, but then again i think that's what i'm experiencing anyway....

and a propeller on the top of my screen,,,,er, no

Mad as a box of Frogs.

Bill X

I like the way you're thinking...

Shark fin on helmet?

" experts say he snapped his neck when glancing to the side due to a home made aerofoil on his helmet"

Maybe the Laminar Lip works, but it sure is unattractive.

A related thought - How about a wedge-shaped windscreen, that will deflect the wind sideways instead of upwards?

Mike

But not much more unattractive than a windscreen in the first place.....:

Yes the laminar does work!

Years ago I experimented with shields and airflow on the windshield of a BMW K75RT. It had an electric windshield that could be raised and lowered on the fly. I made a laminar lip for it. (I actually cut off the top of a tall shield and used the cut off portion to make the laminar lip.) That gives you a laminar "jet" that is smooth and pretty fast. When adjusted to go over your helmet it works very well.

There is also a rubber trim strip that is put along the edge of the shield that works in the opposite way, it produces small scale turbulent airflow which reduces the perceived pressure of the wind off the shield. It doesn't work very well and may be a myth entirely.

Another idea that has been proposed but never executed as far as I know is a row of small (1" x 1") fins set just below the top edge of the shield and turned 30-45 degrees to the flow of air. These spoilers generate turbulent flow and are frequently seen on airplane wings.

After many experiments and $$$ I never found anything that worked better than the original power adjustable windshield. You had to adjust it with any given speed and riding position.