Wind turbulence and half doors

[Reiver]

I have looked online but will ask here too as many who were chatting about this had the racing short screen.

 

When I took the doors off the r400 and put the wind wings/deflectors on I was taken by surprise at the amount of turbulence, this with the stock full windshield. 

 

In my other 7, with the clamshells covering the front wheels, the turbulence is a great deal less...not really an issue doors off.  They really do catch a great deal of wind and direct it elsewhere.  Obviously not efficient for drag but great for the street.

 

The cycle fenders/doors off r400is a wind storm.  Has anyone gone the 1/2 door route with full windscreen?  If so, how much did they help in your estimation.

 

BTW, I do a lot of 60mph driving locally in and around our town as we have 65mph state roads and Hwy 73 (I pull out on 73 going to town from our drive)

 

 

[Slonie]

I am curious about this one as well, as people often pair the half doors with the aeroscreen and I run a full screen.

[Reiver]

It appears we are going to remain curious..... I may mock up something for a test drive before I invest or get serious about the issue.

[wdb]

My understanding is that the combination of cycle fenders and full windshield ends up pushing a lot of air into the side of one's head (in my case at any rate). The windshield side wings I added to my car reduce the effect. I suspect it is a swirl/vortex coming off the outer edge of the windshield. I can push the wings out further and feel a further reduction in buffeting, which supports the theory.

 

I don't know how much a half door would do to stop that from happening, but my WAG would be "not too darn much". Everything is happening higher up. 

 

Here's a chronicle of one fellow's attempts to 'fix' the situation.

 

https://fernlahone.wordpress.com/2014/08/16/experiments-with-wind-deflectors/

[Reiver]

I have the side wing deflectors but didn't notice a great deal of wind reduction...as demonstrated by that link you posted.  You might be right about half doors not being the solution too .....

[JohnCh]

I experimented extensively with wind deflectors on my old Westfield. I found the key was to extend the length well below the door cutout and angle them very far forward, as shown in the photos below. Not particularly attractive or aerodynamic, but with them in place, turbulence was much closer to running with side curtains than without. 

 

 

 

A few years later, I mocked up half doors out of cardboard. Compared to the wind deflectors, they did a much better job reducing turbulence in the cockpit from about mid torso down, but unlike the deflectors, they didn’t do much to stop the wind from hitting me square in the face. Although, it's possible that in combination with the smaller, commercially available wind deflectors, they would have done an acceptable job in that area. 

 

-John

[CBuff]

I came across this simscale model of the 7.  Not sure of the voracity of this simulation. But to John’s point it does look like a lot of the wind is coming from the side of the car and being pushed into cockpit from rear wing.  Would a half door mitigate this ?  Not sure 

 

https://www.simscale.com/projects/jfazeli/caterham_aero/

 

Edited March 15 by CBuff

[JohnCh]

One thing I noted during my half door experiment is that like the side curtains, they virtually eliminate air flow around the legs, which can lead to heat build up on hot days. At some point, I want to experiment with deflectors/ducts around the windscreen to see if systematically channeling air into the cabin can address that low-pressure zone and mitigate the issue. 

[Reiver]

Thanks gents...good info and pics.... 

[Outbound]

Half door with the windscreen works really well for me. 
 

i also prototyped a half wall on the back of the roll mount. Full coverage actually makes it worse. But covering up halfway improved things a lotttt. 
 

later this year I’ll be making a more permanent acrylic panel that looks clean. The clear tape was more quick and dirty prototyping.