Wind Buffetting

[Graham Hutton]

I'm feeling like I need to try some more combinations to work out the optimum!

In my SV with a windscreen, it is great with no crash helmet and the sidescreens on, but if I put my helmet on it is horrible and my head bounces around like a windsock! If I take the doors off and drive with my helmet it is great too but completely unmanageable without a helmet as you can hardly breath at speed.

So, Has anyone got any experience of driving with half doors, a windscreen and no helmet? And has anyone got some old half doors for an SV I could try/buy?

I guess the only other option is to go for an Aeroscreen. I'm keen to give that a go too but it does rather commit me to driving everywhere in a helmet. Do people switch between the screen/aeroscreen regularly and if so, is it a quick job? I've assumed it might be fiddly with the heating screen connectors etc.

Lastly, whilst I am sure the wind deflectors on the side of the windsceen stanchions may be an answer, I don't like the look of them.

What a ramble for which I apologise but I would welcome any thoughts.

G

[Tazio]

As a committed aero driver, I have recently done a few experiments with one of my cars, an early crossflow with a standard floor.  The best configuration I found was with a Brooklands set up, as the angle of the screen can be adjusted, resulting in less buffeting, plus the car was quieter..  I only ever wear a helmet when it rains, as I find them claustrophobic and compromise vision, a headband, ballistic goggles and earplugs are, for me, sufficient.  When I put the windscreen on and complete doors, the car was filled with a cacophony of sound, and was much louder than with the Brooklands set up, removing the doors resulted in the buffeting you described, and the drive was really unpleasant at 60 mph.

I also have another car, it only has a single drivers seat, and has a lowered drivers floor with a single perspex race screen, plus a fabric half door, rounded off with a aluminum race tonneau, I'm only 5 foot 7 in, and feel as snug as a bug as they say. 

Alan

[Jonathan Kay]

If the helmet makes a big difference I'd be interested in how high your head is. Which leads to the question about a lowered floor, as above.

Jonathan

[Graham Hutton]

Thanks Alan. Very interesting. I much prefer driving mine without the side screens and on track days I do just that. I should've mentioned that I have lowered floors but then again, I am 6'3" which doesn't help. I think I might try and find some half doors and give that a go on the road.

G

[7 wonders of the world]

I also have another car, it only has a single drivers seat, and has a lowered drivers floor with a single perspex race screen, plus a fabric half door, rounded off with a aluminum race tonneau, I'm only 5 foot 7 in, and feel as snug as a bug as they say. 

.......and a booster seat too..... 

 

[7 wonders of the world]

Lowered floors, full width aero screen, half doors and ballistic glasses - ear cover for longer trips much much better than a screen and side screens.  

 

[graearea]

aero + half doors + helmet = fine, not bad over 100mph and I've had it up to 130 at nurburgring down the hill.

aero + no doors + helmet = horrible buffeting. couldn't see very well over 100mph as head was bouncing so hard.

full windscreen + side screens + helmet = fine. I've not had the same problem that you have. I'm not tall but I do have lowered floors.

honestly, I wouldn't drive with no screen and no helmet. I appreciate plenty of people like it, but I've had cracked screens before. I've driven to tracks with the screen on and swapped over to the aero and half doors when I got there. it's a bit of a faff fitting it all in the car, but the aero zipties to the rollbar and the screens fit into the car ok. swapping is a 20 minute job.

[Tazio]

Oy,I'll have you know with my couple of herniated dics I am even more 'vertically challenged'

[7 wonders of the world]

Anyone seeing you out for a blat could be mistaken for thinking this was the worlds first autonomous Caterham.....     

[Tazio]

Ouch ! lol

[7 wonders of the world]

[Drakman]

If you are referring to the clear side screen wind deflectors, i don't think they do much.  I fitted a set and used them once, i don't like that they sit on the paintwork at the bottom either.  

I just had a thought, I have a BMW M roadster that has a wind deflector between the seats and that seems to help but it also has a curved windscreen.

[Jonathan Kay]

There are reports of improvement from bending the acrylic deflectors to improve the fit. Hot air, hands rather than other tools, and go for it.

Jonathan

[Gareth H]

I've been trying to find a screen that reduces the buffeting (and wind noise) on my Multistrada, on later models Ducati space the screen off the fairing and have a cutout  to allow air to flow up the back, this seems to reduce turbulence off the top of the screen, it did occur to me that the same principles might improve the side screen wind deflectors, as your really looking to just prevent turbulence and clean up airflow around the side of the screen.

[Jonathan Kay]

Chapman's venturi windscreen:

Jonathan

[mantioras]

Hello. Has anyone tried to replicate this "stacked" deflector principle on a Caterham, with some kind of an aeroscreen fitted in front of the windscreen?

This idea popped in my head after I did some tinkering with my SV to reduce buffeting. Having read about the blocking screen between the headrests, I attached a retractable sunshade, which is usually mounted in cars on their rear shelf. Pics attached. Seems it has helped a bit, and visbility via the internal mirror is quite ok with the share up. However, there still was turbulent air, so I decided to try out side deflectors/blockers from clear plexiglass. I was expecting that some crosswinds might pass into the cabin through the side gap between the rear of the door and the rollbar, ie. this sunshade/windblocker I had installed. While driving with all the setup in place the shade/windblocker was still being pushed into the cabin quite heavily, meaning that the air going above the windscreen is being sucked into the cabin: and some of it is blocked, but a considerable amount still goes right down behind our heads, in front of the windblocker shade.

So one idea would be to secure some "aeroscreens" on top of the windscreen (something like Brooklands type, eg. two flaps), or to attach something like a usual aeroscreen to the scuttle or the bonnet in front of the windscreen. The first option should throw the air higher and further up (but might actually increase the vacuum and result in an even stronger suction, so must be tested), while the second one might work as the aeroscreen was intended, with the windscreen serving only the purpose as a shield from bugs/stones/rain/whatever might hit you into your face.

I cannot replace the windscreen with aeroscreen due to numerous reasons, and am quite tall (6ft3in), so buffeting is a bit annoying. Hence the idea of an aeroscreen (or two flaps) in front (not on top) of the windscreen, which would not block any view (but I'd still prefer the clear ones). If that works, I would happily remove the rear "curtain" and the side screens, to retain the cleaner original looks, even though 20 euros for the first one and 10 euros in materials for the pivoting screens is a bargain and works somewhat :) BTW might not be obvious from the pictures, but the rear shade can be put up and works with sidescreens in place. They pivot to ease the entry and exit from the car.

[Benton]

Don't know if you've come across this article 

[jbcollier]

This works really well for me:

 

[mantioras]

Benton, that was exactly the article which inspired me to add those side deflectors behind the doors :) But the author was trying to drive without any doors, and I guess he still accepts higher buffeting than myself.

jbcollier's option is also interesting, but I personally find that my problem is no longer the wind from the sides, but rather from the top-to-back. While driving with the deflectors in place, I noticed that they are under quite strong pressure to be pushed inside, so they definitely protect from the wind entering from the side. Yet I still feel strong cool breeze on the back of my neck and around ears, even with appropriate clothing :/ Hence the urge to solve the air flow going over the windshield.

[PlastererPete]

I wonder if someone has developed a sort of aeroscreen attachment that could button to the top of the windscreen to aid the air travel further backwards. Kind of like the mercedes soft tops have that spoiler that raises above the windscreen to control the airflow.