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For those of us doing street cars, we have to satisfy some sort of inspection process, which seems to vary appreciably by state. I'm not sure the organization inspecting in my state, the California Highway Patrol, would understand or accept that low windscreen without wiper blades. I don't know that they would reject it out of hand, but I'd want to check before I committed to it as a solution.

That said, it certainly is interesting that something that's basically a big bump appears to do a better job than a complete windshield. It certainly is counter-intuitive.

Its counter-intuitive until you realize that air is like a woman. You can make it do something, but only at great cost. Subtle suggestions are very effective and cost nothing.

Bill

I too have done some "yarn" aeronautics like Jack, but at speeds a little higher than Jack did in his videos. That little kick-up is amazing in it's ability to create a calm bubble. In my tests, that bubble got smaller and smaller as I increased the speed, untill it was practically non existant at about 100 mph. Also of great note: big bugs ignore abrupt changes in air flow created by that lip (don't ask me how I know that). A June bug at about 70 raises quite a welt on the forehead.

Tom 3-eye

it would be a great help if some enterprising locost owner would do the same test in a car with a conventional windshield, with and without side deflectors, then we could see where the buffeting is comming from.

it's a simple experiment, but i can't do it because i have not finished my diff yet due to parts availability.

is there anyone out there who wants to do it for me and post it?

my state requires that a windshield of safty glass and wipers are fitted, unless your car is a side by side quad.

a word about that, these things are classed as motor cycles, they can do upwards of 50 mph, seat at least 4 people, do not require an emergency brake or a windshield, and you can drive them on a car licence without a motor cycle indorsment, no helmet is required, only eye protection

watching jack's vidio, perhaps i am looking at this all wrong, if there was a similar bump before the windshield, would this create a dead area in front of the wind shield such as a cleaverly designed hood scoop thus stopping the effects of the windshield.

we all know that the drag of the windshield is the biggest problem in streamlining a locost, have i hit upon a device that could improve the speed and stop the buffeting.

a word about buffeting, i live near Las Vegas and the best buffet is at Samstown!

I haven't seen it referenced in this discussion yet, but a couple of years ago (or so) there was a discussion here on locostusa about venting air under the windscreen (or through a port in it) to reduce buffeting by reducing the low pressure area behind the windscreen. From what I recall, testing did show some potential for the idea. It might be worth doing some searching to see if there is information in that thread you could benefit from.

For John,

Andrew posted the following picture some time ago ....

It gives some indication as to why 'wind-wings' aren't all that effective, but why full doors would be.

I think you may also want to re-consider your approach. A simple mesh or perspex screen behind the cockpit will reduce buffeting and turbulence in the cockpit. These are sold commercially (http://www.windblox.com/) but could be fabricated pretty easily. Make it removeable.

Thanks for posting that link IslandMoose. I may try something like that on my car.

well i've made a door but i'm not happy with it, its steel and heavy, it can be completely removed by undoing two 1/4 bolts.

now i see the doors on Ariscmarques's car and am wondering if i can do something in aluminum, all aluminum, door and window frame from one sheet with some ally angle riveted to the lower edge for stiffness, i'll work on that one, it just depends on what extrusions are available locally, well 65miles away.

so many weeks on and i have a roof, this is a nice roof, although i say it myself, i also have half doors which seem to do a good job of reducing the wind buffeting.

but here's a strange thing, before making the roof, thats the real roof, i made a test piece roof from old scraps of a boat cover so that i could use it as patterns for the real one, i didn't bother to put a window in it and just left the hole.

wind buffeting was minimal with the tempory roof, half doors and windshield side deflectors, i could not light a cigarette but still pritty good.

now i've made the real roof with a window in place, what do you know, the buffeting has returned.

the more i think about it, the more obviouse it is, i started looking at old cars made in the 20's and 30's, they all have a way to allow air into the car from the front arround the cowl area.

i also have a 1962 ski boat, on that, there are openings at the bottom of the windshield to allow air into the cockpit from the front.

so i think i will experiment by allowing air under thw windshield by removing the strip at the base of the wind shield and going for a drive at about 70 mph to see if it works.

I look forward to reading the results of your test I think it will work well and am thinking of installing my windshield so that I can ether raise it or open up the bottom somehow.

That will also let in water.

True, very true... Out where Mr. Hennessey lives, that will only be a problem for 15-20 minutes a year. The rest of us, wellll.... Could get a mite damp in the cockpit...

Very interesting discussion, and one that i am dealing with at the moment....took off the two Brooklands and replaced with a reproduction Lotus 7 windscreen (used a 7's old glass for the pattern and Jack bent the frame to fit it).

I went from 'windy' but not bad, to 'unable to wear a cap of any kind that doesn't have a chin strap'.... the buffeting is amazing.
Now, when I added the top, I thought that would solve it....nope....tons of wind coming around the sides of the windshield....
The added 'sides' of my tonneau that I leave up if it is cool, should have cut out the side draft....nope....just as bad....

The funny thing is my MGTD has no buffeting at all.... noisy, bit of wind, but not the 'suck your hat off' type that is occurring on the 7.... very strange.....certainly similar windscreens, except for the curve at the top corners.....?