windshield

[aerohead]

Originally Posted by California98Civic

Here the 1924 enclosed limousine, I believe:



Not so good over the top, is it. But most air, as you said went around the side. Maybe that was much cleaner, given the shapes.

james

James,this is the animal alright! Thanks!
I'm seeing a little of Prandtl's 'line of discontinuity' right before the forward header,then the flow appears to hug the rooftop until it breaks away at the back.
Four streamline smoke filaments are dislocated into the crowded space above the roof,but I can't see any 'daylight' between the roof and smoke.I interpret that as 'good' flow,although I'm just an amateur.
Compared to some wind tunnel smoke photos I've seen I'd have to say that Rumpler new his way around pretty well.

[aerohead]

Here are some images from a FIAT SAE Paper from circa 1987.
You can see how there are diminishing returns as the angle is lowered,then goes asymptotic at 64-degrees,with no further drag reduction beyond this angle.

Here is the FIAT drag curve for the cowl/windshield intersection that Frank was asking about.Again,the curve 'flatlines' at a particular angle,with no further benefit.

This lower image prompted the hood blister for the T-100.

[kach22i]

Nice couple of charts.

Do you have anything on the plan view?

As in Saab 99 or Lancia Stratos type curved windshields?

Closest related commentary I can recall is the air-cooled VW Microbus critic.

The one which argued that the corners had a radius beyond the minimum required.

And that the bow or arc of the front fascia panel where the famous VW emblem is, is curved outward beyond the minimum required.

Apparently this guy liked to keep things as boxy as possible.

[aerohead]

Originally Posted by kach22i

Nice couple of charts.

Do you have anything on the plan view?

As in Saab 99 or Lancia Stratos type curved windshields?

Closest related commentary I can recall is the air-cooled VW Microbus critic.

The one which argued that the corners had a radius beyond the minimum required.

And that the bow or arc of the front fascia panel where the famous VW emblem is, is curved outward beyond the minimum required.

Apparently this guy liked to keep things as boxy as possible.

I've been creating and compiling images for a dedicated thread on plan-taper.
Hucho describes 'saturation',in which once the optimized radius is achieved,no further increase in radius will produce additional drag reduction.
However,if you continue into the chapters on commercial vehicles,he shows drag tables which clearly illustrate that the 'bulbous',or 'oval' forebody has the lowest drag in crosswinds,which is generally 'where' we all drive statistically.
R.G.S.White of MIRA conducted wind tunnel studies for his 1968 low drag recipe car,and his quanta support the low drag aspects of the 'bulbous' nose,which dates to 1911.
Here is Moller's research from 1951

Here is White's lowest drag iteration

which dates to Jaray's patents of 1923
Jaray's shape is at top,the 1911 form is 3rd from top

Jaray's streamliner in plan-view