Aeroscreen buffeting

[NigelO]

OK, I was never expecting serene calmness, but I'm getting a bit irritated by a severe buffeting at certain speeds. I'm wondering if any other aeroscreen owners get it, and if so, what they've done about it.

 

Some things I've noticed:-

 

• It only happens at (ahem) "motorway speeds", despite me almost never venturing onto a motorway... 😉
• If I move my head forward by about 6", it almost stops, but then I look really daft and its uncomfortable
• It could be a function of my crash helmet design, as I don't seem to get the buffeting when I'm not wearing a helmet.
• It could be a function of my seating position / angle - it's a bike helmet and bikers will tend to be in more of a prone position while riding

 

I'm wondering if it can be cured by altering the angle of the aeroscreen (is this even possible?) or by adding a "Gurney flap" to the screen (youngsters will need to Google this...). I don't want a higher screen, as I'm only just looking over the top of the standard screen - I'm just thinking that if the angle was a bit steeper, it might deflect more air

 

I considered a carbon screen from Carbon NV, but I actually rather like the OE aeroscreen and the section of body colour.

 

Any thoughts?

 

 

[CosKev]

Presuming you wear a motorbike helmet they are not designed to be worn so upright for a start.

 

Main thing I noticed with mine after fitting new seats was how much difference the height makes, I was fine with Westfield race seats,but fitted JKs which I didn't realise made me sit higher in the car at it was awful.

So I lowered floors and all is good again!

[Kingster]

Mine is fine with a helmet (bike and car versions) - never any buffering even at 100+ on track. 

 

I always wear a helmet, have JK’s, lowered floor and Carbon-NV screen. I adjusted the screen angle to suit my height. 

 

[Ian Kinder (Bagpuss) - Joint Peak District AO]

I’ve got the factory aero screen. I find it noisier with a helmet and use ear plugs for longer runs. It’s been tested up to 130mph on the ring, though didn’t bother with ear plugs for one lap. 

 

 

[AdamR]

1 hour ago, Chris King - Webmaster and Joint North East AO said:

Mine is fine

 

 

I think the more vertically challenged members (me included ) will tend to have better luck

 

That said, I was never really happy with the 'double bubble' type screen, despite increasing the angle as you have described Nigel.

 

With a 'blade' type one fitted things have always been much better. Even my current 'screen' (a bit of bent lexan about 3" tall and 8" wide) is tons better than the double bubble.

[Kingster]

22 minutes ago, AdamR said:

think the more vertically challenged members (me included ) will tend to have better luck

It’s true - good things come in small packages 😁

[NigelO]

Just a thought - the OE aeroscreen is located with just four captive bolts - two along the front edge and two at each end, on the side of the scuttle panel.

 

Is the screen flexible enough that if I slotted the locating holes in the scuttle, I could raise the trailing edge slightly?

[CosKev]

I cant remember mine being very flexible.

I think you could do what you describe,and add some wedge shaped spacers onto the two mounting points on the top of screen?

[AdamR]

Yeah you can do that. Just loosen the front two bolts to allow articulation, and use large washers on them. Front of the screen doesn't have to be flush with the scuttle, IYSWIM.

[Davemk1]

I'm tall and use an aeroscreen and found that I needed to add a small extension to the screen to limit the buffeting. I experimented with cardboard and came up with the final height and shape that gave the best protection. I made a clear plexiglass extension that you can see in the photo if you look closely.

 

I know that if I could move the screen back and closer to my head that it would work better (like you if I move my head forward i get cleaner air) but that's not realistic. Mine now works very well for me as long there's not a strong wind blowing from the driver's side of the car - if that is the case I get more buffeting than I'd like.

 

dave

[Dave Eastwood (Gadgetman) - Club Chairman]

2 hours ago, NigelO said:

Just a thought - the OE aeroscreen is located with just four captive bolts - two along the front edge and two at each end, on the side of the scuttle panel.

 

And the centre brace at the rear of the screen?

 

You can see the little aluminium brace, circled in blue, below.

 

 

Mine was set quite low, as you can see, here, as I’ve quite a long back, so sat quite tall in the seat, I found that gave good results for me.

 

Certainly my head (with car type helmet) only really got much buffeting above 110/120 mph, where it could be severe. BUT, my helmet is an old fashioned design, pre-aero. I did try a borrowed one, with various spoilers built in, and it was miles better.

 

 

 

[NigelO]

I use a home-made carbon centre support - I could pretty easily make another two-piece version with adjustable height in order to support the raised height

 

That said, I suspect if I find a screen height that stops the buffeting, I'll never put it back to a previous position, so I might just make a new taller version to suit

[maurici]

10 hours ago, AdamR said:

 

I think the more vertically challenged members (me included ) will tend to have better luck

 

That said, I was never really happy with the 'double bubble' type screen, despite increasing the angle as you have described Nigel.

 

With a 'blade' type one fitted things have always been much better. Even my current 'screen' (a bit of bent lexan about 3" tall and 8" wide) is tons better than the double bubble.

That double bouble one was particularly ****...

First time i drove the car in anglesey with a motorbike helmet, nearly got a neck injury.

 

Car helmet and slighly different driving position was a tiny bit better... but not much. 

 

As you say with the current blade one i do have, and sat in the floor, things are much, much better.

 

 

[stephenh]

In my experience, using a crash helmet which is aerodynamically good makes a world of difference, particularly if you sit quite high in relation to the top of the aeroscreen. I found the V2pro to be very good from amongst the budget end of FIA standard helmets. It has a small lower lip, which helped to stop the helmet trying to lift at high speeds.

[Kingster]

14 minutes ago, stephenh said:

found the V2pro to be very good from amongst the budget end

I have one and was pleasantly surprised at it for the price. But being a short-@rse also helps 😁