TREVORGIDLOW's Blog

Hi,

 

To the best of my knowledge there aren't any commercially available "rigid" deflectors of the type you describe, even the mesh jobs are a recent response to customer demand that tends to get used once or twice, then abandoned!

 

I have seen a few home made deflectors, simply cut from a flat sheet of acrylic, (or preferably polycarbonate), and fixed in the roll bar opening. How effective they are though, I don't know.

 

The side screens - doors, are surprisingly effective at reducing the worst of the turbulence in the cockpit, but ultimately, the shape of the cars and the shear uprightness of the windscreen means that you're never going to get the sort of buffet free quality you can get in a convertible tin top.

 

Ironically, the best way to get rid of most of that turbulence is actually to loose the windscreen and fit an aeroscreen! But that introduces its own set of problems...

 

Do perhaps try borrowing a set of side screens though, you'll be surprised at the difference.

As stated, it's an open topped car and you're always going to get buffeting.  The windscreen cutting through the air creates a low pressure zone in the cab, and as nature abhors a vacuum, the air rushes in from behind to fill the low pressure area, which is why you get buffeted from behind.

 

If you really want to get buffeted, take the side wind deflectors off - you'll find you can't breathe after 60 mph. This is commonly known as "Westfield nose".

 

A rear mesh and perspex roll hoop wind deflector will help slightly, but it won't eliminate it.  Full side doors work pretty well, but you do lose some fun IMHO as it can feel a bit claustrophobic.

 

Side wind deflectors, a fashionable head scarf for the missus, and good sunglasses / goggles is how I tend to run, along with keeping a good hairbrush in the boot box.  You need to enjoy the experience rather than fight it too much.

Hi Dave/Scott,

 

Thanks for your helpful comments. For the avoidance of doubt I get the wind in the hair experience, this is one of the reasons for me buying a Westfield, love the philosophy ridding the car of all non-essential items and returning to raw engineering/ driving experience. Interesting comment re: aeroscreen, also looks better in my book, but unless your racing, the requirement to wear a helmet seems to defeat the purpose of an open top car?

 

The turbulence is fine for me, just thinking if perhaps 10% of the time when I do have a passenger, I would like to think that they are not struggling for breath!!!

 

Summary: Have the feeling that 'wind deflector doors' might be the way to go, although I detest the look of the things, so might have an attempt at fabricating something from polycarb, although I am sure there is a reason why these aren't readily available...probably flapping issues. Anyway, will update you, but it might take a while. T.

Yep, you can run an aeroscreen without wearing a helmet, but that's one hell of a risk to take and I don't know anyone who would.  Helmets are fine of course, but SWMBO has to be a pretty good sport to get out the other end of a trip with hair like a troll.

 

Half doors with the wind deflectors are well spoken of as an alternative.

 

Finally, and this may sound obvious, is the passenger seat all the way back against the rear bulkhead?  If it's on runners, bringing it forward somewhat might change the dynamics just enough to work.

There is no reason why there should be turbulance on one side and not on the other IMO.  I think some people have wind deflectors that are too big and so increase the backdraft.  Mine are smallish and I have no problem with breathing, talking or listening at almost any speed (officer)!

Scott that's an interesting point, I hadn't thought of TBH. Probably because I'm 6ft2 and the seats are nearly always against the bulkhead. May also be the reason why I have experienced this! I snapped up my Westfield on last Friday (picking up tomorrow) :-) not least because it is the only one I've sat in where I don't feel as if my legs need to be shortened to get a decent driving position! Thanks again. 

Being taller than average is definitely a factor.  Does the car have lowered floors (lower than the chassis rails)?  If not, although fitting them is not a quick and simple job, it can make a significant difference and also give you more room between the bottom of the steering wheel and the tops of your upper legs.

More interesting information! I have no idea I will check this out.

It's a weird thing, particularly obvious with the double bubble style factory aero screen, (and no, I don't know the reason either), but I've heard so many people report that turbulance is greater on the pax side, that I suspect it's common, more or less, to all. The other odd thing with the aero at least, is that the height of the (strong) air stream that you feel hit you, when at speed, is lower on the pax side than the drivers side! So where as the driver has it pass over head, roughly, the same side pax tends to get hit more in the forehead! Weird, huh.

 

As an alternative to headscarves, "Buff's" are very popular, both for drivers and passengers, and are available in huge ranges of colours/patterns, both unisex and mens/womens styles. 

I think the person in the passenger seat is more sensitive than the owner driver.  There is no aerodynamic reason IMO.

The weird thing is that I have been in the passenger seat and the driver's seat in the same car for 2x Westfields with and without the side windscreen deflectors and each time I definitely noticed that by the time we we doing 40 - 50mph, my breath was becoming laboured in the passenger seat only (yes really!!). I'm 6'2" and I can only assume that because of my height I was getting into a vortex that results from passing stuff on the nearside, either that or I'm a complete wimp.

 

Anyway tested on 4 different passengers - all shorter and it was fine for them. So it appears to be a non-issue since I'm going to be in the driver's seat, pretty much all the time!!

I think the person in the passenger seat is more sensitive than the owner driver.  There is no aerodynamic reason IMO.

 

I've had it demonstrated to me in my open car by trading places with the passenger.

Do you have an explanation for this??

It MAY (or by logical extension, may not) be something as simple as arm position.  When you think about it, the only difference between sitting on one side or the other (if the car has either two external mirrors or none so it presents an identical face to forward wind resistance on both sides of the car) is that the driver is sitting with their arms raised and their hands on the steering wheel.  What I'm saying is that a raised arm or two might be sufficient to redirect the air current just a bit.  The only way to prove it would be to drive at speed with your hands off the wheel and your arms in your lap (not recommended).

 

On the other hand, would you like to see my hat?  I'm currently talking out of it.

Do you have an explanation for this??

 

No but have had enough empirical evidence including trying it myself that I know something is happening! May be its because Westfields are

asymmetrical  down the centre line, I don't just mean the infamous difference on the tub, but also the effects of the exhaust on one side and carbs/throttle bodies on the other, could even be related to the angle of mirrors fixed on and around the double bubble aeroscreen, or maybe the double bubble screen itself is subtly asymmetric. Or as Scott said, an effect caused by the drivers position holding the wheel.

Don't know if this will help you, I'm 6ft 1 and spurned on by a visit to a caterham open day (and sitting in a few) i was hell bent on getting my seating lower.

 

In the end, after looking at a good few posts on here, I ordered some nice new strong bolts and mega giant washers, took the seats off the runners and bolted them solidly to the floor - no new holes were needed. 

 

The feeling from being lower in the car is amazing - more sitting in than sitting on if you get what I mean.

 

Additionally, I got hold of a set of the newer type side screens. they go higher and back further - and really reduce buffeting.