Modern Vespa

I read on MV that there are performance benefits when you install a windscreen.

I would think that it would slow you down cause of the resistance.

Anyone have any insight on these things?

Thanks!

yes fitting a screen will give you some more speed but only really at top end speed.

It helps to divert the air flow over you the rider instead of hitting you in the chest or helmet.

I dont really know the comparison though between the small screen and the large screen like the US guys ride with. 8) 8) 8) ..

so I guess the next question is, do I get this:

http://www.scooterwest.com/item_detail/ET-Mid-Size-Flyscreen/289/

or this:

http://www.scooterwest.com/item_detail/ET-Small-Flyscreen-Cuppini/290/

or this:

http://www.scooterwest.com/item_detail/ET-Sport-Flyscreen-CLEAR/292/

Personally, I think the latter (small one) is more pleasant aesthetically, but does it have the performance benefits??

Thanks!

I have just put the new GTS Super one on mine 8) 8) 8) 8)

I bought a large Vespa screen. There is a warning sticker on it that warns you not go over 60 mph (I think that is the limit--I'm at work now so I can't check it) because it can cause handling problems. I don't know if it does, because I cut down the screen to mid-size right after I received it. That size works fine at 75-80 mph (GTS). There is a little buffeting, but not very noticeable if you wear a full face helmet. It's more noticeable if you wear a half or open face helmet.
I bought the full-size screen because it protects the hands from the wind. I cut it down because I want to look over the screen, not through it. After the winter, I'll take it off and switch back to the small flyscreen.
With the flyscreen, I don't know if the scoot is faster or not. The dealer threw it in free, so I've never ridden screenless from the day I purchased the scoot.

Two-wheeler aerodynamics work far differently than you might think. A human body, as seated on one, produces an incredible amount of drag. Most bikes are pretty bad themselves, from an aero perspective. This is why motorcycles don't get the mileage on the highway that a lot of people expect.

A big fairing or windshield might increase your frontal area, but improves the form drag of the rider/bike combo so much that overall aero drag is substantially reduced.

I don't think you'd get much performance improvement from the small screens, if any. The really bad part of the system (you) is still sitting out there in the wind, pretty much the same as without it. The bigger screens would definitely make a bigger aero change, but without a wind tunnel, or some careful experimentation, there's no way to know how much change you'd get for a given bike/rider combo.

I just put the large screen on my S 150 a couple of days ago, but since I'm still breaking my bike in, I haven't had it up to high speed anyway. I may run some experiments next summer, but they'd be pretty crude for sure.

I disagree

The small screen adds about 5mph at top end speed....

I have the Faco mid size screen--similar to your top link of the the three links. It's not the prettiest thing, but it allows me to look over it, it blocks the wind from my hands, and it blocks the wind from my chest. There is some wind noise at helmet height, so if I had my druthers, it would be about an inch taller, which I think would stop that. But it's not a bad all around windscreen.

Whether the scoot goes faster or slower, I don't now--never rode it without the screen in place.

Cary

I would install a Laminar Lip (www.laminarlip.com) on mine to reduce or eliminate the buffeting, if I knew which one would fit a cut-down Vespa screen.

Why not cut the super tall one down half an inch every week or so rather than buying a extra bit of weight to attach to your screen? You'll know when you've cut too much.

LL isn't all it is cut out to be.

That does surprise me, but again, two wheeler aerodynamics are ridculously unpredicatble, without a wind tunnel anyway.

Riding home tonight, it ocurred to me that the basic scooter shape would resist good streamlining. Anything you did to reduce form drag around the rider would probably move the aerodynamic center of pressure farther forward, ahead of the center of gravity, which would reduce stability. Considering the rearward center of gravity you already have with a scooter, a light, slick fairing might be really squirley in a crosswind.

Of course that could be offset with some kind of large tailfin, but I can't even imagine how dorky that would look.

+1

I have used all 3 sizes on my GTS. The tall screen slows you down and reduces top speed, but it is the only one that is quiet and keeps you warm. The midsized screen helps tops speed and gas mileage. But it directs all of the air to the top half of your helmet - very noisy. The small screen gives you better mileage and top speed. It directs the air to your neck and shoulders, so it isn't any noisier than no screen. Most of the people I ride with have the small screen, and that is the one I use now.

And then what do you do?

I use the Faco mid -size, and +1 on the helmet noise. It IS dramatically increased. But it doesn't bother me all that much because 1) I have a Shoei Full face helmet RF-1000 which is pretty good aero-wise and WAS quiet before I added the screen; 2) I'm only 5 foot 8 inches; 3) I'm half deaf anyway, so I use earplugs and no problem; 4) I can close off the chin vent and get a big reduction in noise; 5) It seems to handle better with it on than naked. The wind is hitting the top half of the helmet.

FWIW: My eyes are about 3-5 inches or thereabouts above the top of screen, and I have a short upper body/long legs for that 5' 8". If I drop my head slightly I can tuck in easily and noise drops away for higher speed sections.

You've tried LL? How about changing the angle of deflection of the wind using a deflector made by Touratech? I think that cutting down an inch at a time won't work too well. I believe that between the tall screen (higher than your helmet and face) and the flyscreen (deflects to your chest and shoulders), everything else that is intermediate is about the same, unless you change the angle of deflection at the top of the screen. The Touratech deflector can do that, but it''s an expensive (and kind of ugly) alternative.

The Laminar Lip absolutely does work. I have one on my GTS and another on my wife's GTS. I first used one on a BMW R1150R that I used to own and it eliminated the buffeting that I was experiencing.
On my GTS, I cut down a tall screen to where I could see over the top but I still got turbulence and buffeting. I installed the the L-Lip and lowered the shield with the adjustment rods back to the same height so I could see over the top. The turbulence & buffeting was gone. I did the same thing on my wife's scooter and she says it was a night vs day comparison.
I used the Universal, 17 1/2" Lip on both scooters. It fit perfectly with no adjustments on my Cuppini windshield. On my wife's Vespa windshield, I had to heat up each side of the Lip where it attaches to the windshield with a heat g u n so I could slightly bend the plastic on the lip to conform to the same contour as the windshield. This took less than five minutes. http://www.laminarlip.com/cruisers.php

I would highly recommend the Laminar Lip to anyone who is having a turbulence/buffeting problem. The only restriction would be that with the Lip attached that you will look over the top so that you can see the road approximately 10 feet in front of you. This will give you the correct height so you can experience the benefits of the Laminar Lip. If your windshield is too short, you're still going to get some turbulence.

I bought a large Vespa screen. There is a warning sticker on it that warns you not go over 60 mph (I think that is the limit--I'm at work now so I can't check it) because it can cause handling problems. [/quote]


I checked the sticker. It warns you not to exceed 100 kmph with the tall screen made by Vespa for the GTS.

I have both the LL and Touratech deflector. The TT requires a flat windscreen because of how it mounts. Additionally you have to be able to get the strap between the deflector and the bottom of the screen to secure it in place.

The LL causes additional flex in the windscreen and beat up the mounting holes so much that they're not round anymore.

I've been spoiled by my stock Vespa Tall windscreen - better mileage, little more top end, and the ability to hear myself think while riding.

XLR8--question: At what speeds do you notice the benefits of the Laminer Lip? My typical commute has varying speeds of 25-40 mph, mostly around 30. I get the loudest buffeting noise above 35, but there is still significant buffeting noise at the slower speeds. Based on your experience, would I get any benefit at the slower speeds, or would it all be at the higher speeds?

Cary

Short flyscreen. I just tuck in when I need more.

I installed a large Faco wind screen for winter on my GTS... I had a smaller one for the summer.

I lost... easily, 10-12 MPH in light wind conditions... 12-15 sometimes in a good headwind.

No complaints yet about a "sail" effect but cross/side winds can be rough.

It is very, very loud. A whistle and wind sound. I am looking forward to taking it off in the spring... but for now I am toasty warm! My only complaint about the Faco - it does not cover my hands. Ugh.

winter/big:


summer/small:

I have...the...Touratech deflector. The TT requires a flat windscreen because of how it mounts. Additionally you have to be able to get the strap between the deflector and the bottom of the screen to secure it in place.
/quote]


You have the old TT deflector. The new ones attach differently and don't have a strap.

Plenty of misinformation here, and the most important thing is missing.

Not only is frontal area and shape very important to aerodynamics, but so is airflow BEHIND the shape.

Your body hits the air and it is pushed up and around you. Immediately behind you an area of low pressure is formed. The air that was pushed out of the way by your body is sucked into that void. The air is not guided in any way so there is a messy, turbulent area which messes up your Coefficient of Drag.

If you have a windscreen it pushes the air up and around. There is a dead area in front of your body, but because the air still has to get around you, the airflow is smoothed somewhat, there will be less turbulence, thus less drag.

A small topcase has a similar effect.

Because a scooter doesn't have a ton of power to spare, the effect is pretty obvious.

P.