Excellent paper on rear spoilers

[JulianEdgar]

Originally Posted by M_a_t_t

Do you mean like this?

Yes it's j-u-s-t getting flow attachment - and even then, not at the far end (car's left hand side) of the spoiler.

I was thinking it might be cool to try and replicate the style of a lotus elise rear window area with the over hang and wrap around. My trunk isn't as long as the elises, so not quite the same. Probably end up looking more like a del sol with a roof extension.

I was thinking more a separation edge maybe 25mm long on the trailing edge of roof and C-pillars. But that is just my complete guess - if it were my car, I'd be trialling a whole bunch of things, evaluating especially with throttle stop drag testing.

[JulianEdgar]

The only notchback that I know of with that sort of rear window angle / trunk lid height that was modified for attached flow is the VL Walkinshaw Commodore - unheard of outside of Australia.

This pic shows how much they had to raise the boot / trunk lid to get attached flow... and a spoiler that really did something.



Others to think about include the deflector on the BMW 'Batmobile' 3.0csi...



...and the Impreza WRX (standard STi?) roof deflector.

Some AirTab vortex generators on the uppermost part of the glass / trailing edge of roof may improve flow attachment on the boot / trunk spoiler - may...

[aerohead]

Originally Posted by M_a_t_t

I have always heard the difference between spoiler and wing is that a wing has airflow/opening under neath it. A spoiler is just like a lip or extension on the car. Is that correct?

I wanted to make sure my terminology was the same before asking more questions.

Yes.
The spoiler was introduced in 1961, by former US Air Force, airman, Ritchie Ginther, who was with Ferrari's GT racing team at the time. The whole concept was borrowed from an upwards-directed aileron spoiling lift on a wing for coordinated banked turns in the aircraft.
Dan Gurney introduced the 'Gurney Flap' around 1972. The last ones I saw were hiding underneath the SolarWorld GT, solar racer, to 'jump' the air past the hour-glass wheel houses.
The wing, first used by Mercedes ( if memory serves me ),in an automotive application, dates to a 1930s record car, Germany ), which is chronicled in Baron Reinhard Koenig-Fachsenfeld's ' Aerodynamiks des Kraftfahrzeugs', self-published in 1951. Fachsenfeld also shows the first 'splitter.'
Today's wingtip end caps date to around 1906, a ' capping-plate' invention of Frederick Lanchester, the man who coined the term 'aerofoil.' He also 'invented' the 'streamline body of revolution,' however that actually debuted in the 1700s, with airship 'Le Precurseur' ( sp?) by Frenchman, Pierre Julienne
The wing does rely on 'free-air', out of reach of any turbulence generated by the host vehicle.

[aerohead]

Originally Posted by M_a_t_t

Are you saying to just start with this?

Looks like reattachment on top of the spoiler.

[aerohead]

Originally Posted by JulianEdgar

The only notchback that I know of with that sort of rear window angle / trunk lid height that was modified for attached flow is the VL Walkinshaw Commodore - unheard of outside of Australia.

This pic shows how much they had to raise the boot / trunk lid to get attached flow... and a spoiler that really did something.



Others to think about include the deflector on the BMW 'Batmobile' 3.0csi...



...and the Impreza WRX (standard STi?) roof deflector.

Some AirTab vortex generators on the uppermost part of the glass / trailing edge of roof may improve flow attachment on the boot / trunk spoiler - may...

* The Mercedes-Benz 190 Evo seems like a similar backlight situation. Wind tunnel smoke imaging suggests no reattachment on the boot, however the flow clearly reaches the wing.
'evo2Windkanal.jpeg' is part of the internet address. The rest got chopped off during printing. sorry!