Attached flow on inclined rears, and trailing vortices

[arcosine]

The engine air inlet is sucking in the turbulent boundary layer.

[freebeard]

The inlet is positioned to take advantage of the involuting vortices. The [1500CFM?] is drawn from a limitless supply. No influence on the downstream. IMHO.

[aerohead]

Originally Posted by freebeard

I'll vouch for that. aerohead is putting spaces after periods now.

(But you dropped a trailing ']' on your quote )

There is a lot of focus on the 911 ducktails and whaletails, but consider the Herrod Helper. A bent piece of angle metal held at a position and angle that mitigated the wake without compromising the cooling.

If the 'Herrod Helper' had mitigated the Beetle down to Cd 0.14 we'd really have had something to talk about.

[aerohead]

Originally Posted by arcosine

The engine air inlet is sucking in the turbulent boundary layer.

Good observation!
Years ago I shared a Japanese-built STOL aircraft which employed wing suction to allow very large angle of attack, high-drag, high-lift flight. That plane had 5- jet engines. One of those five engines was specifically tasked with powering the necessary suction air mover for the wings.
Georgia Tech is the most recent university to study blown and suction slots. So far, the takeaway, is, that it takes more power to run the fan, than is recovered from the flow attachment produced.

[freebeard]

0.41 to 0.14 is a big ask. Not sure what I'd have to say. "Add air curtains"?

[aerohead]

Originally Posted by freebeard

0.41 to 0.14 is a big ask. Not sure what I'd have to say. "Add air curtains"?

* Even though the 1939 Porsche 60K10 has been recreated and wind tunnel tested, I've yet to see the Cd published. I suspect that it would come in below the Volkhart V2 Saggitta of Cd 0.217 (pretty sweet!)
* The original AVA G'o'ttingen Lange Car, 1/5-scale model, of which the Gmund and later production Porsche 356 were derived, came in at Cd 0.14- 0.16.
* By 1968, Porsche was down to Cd 0.27 with the 907, long-tail.
* They know aerodynamics.
* And when the 911 debutted, it's Cd 0.40 was way lower than typical sports cars and passenger cars of its day, plus it's small frontal area meant a low CdA. ( consider a early-1950's M.G. TC of Cd 0.75!)
* They've guarded that shape for many decades, only giving way after the last air-cooled cars of the 1994 year model played out.

[freebeard]

I bought a water-cooled VW. You saw it at Darko. A mile of rotting rubber hose and an oil pressure indicator light that is an LED on a printed circuit board.

I'm not convinced water cooling is a good idea in general. They could have gone with high-working-temperature ceramic cylinder blocks instead.

[aerohead]

Originally Posted by freebeard

I bought a water-cooled VW. You saw it at Darko. A mile of rotting rubber hose and an oil pressure indicator light that is an LED on a printed circuit board.

I'm not convinced water cooling is a good idea in general. They could have gone with high-working-temperature ceramic cylinder blocks instead.

The EPA realized that there was a shortage of blown radiators, hoses, heater cores, leaking water pumps, inoperative sensors, thermo-switches, broken belts, dead blower fans, HVAC actuators, thermo-clutches, electric fans, oil filters,ethylene glycol, propylene glycol, and distilled water.
The air-cooled engine was thermodynamically limited in efficiency. The ceramic engine and vapor-phase cooling would have improved that, but nitrogen oxide formation could not be dealt with, and 12-year-olds living along 101 and the 405 in LA County had already lost 10% of their lung capacity to ground level ozone, cooked up from the nitrogen oxide soup.
The water-cooled engine turned out to be more fuel efficient, less noisy, cleaner, very compact considering.
None of that can compete with electric motors, and a generation from now, 'pistons' will be studied in history books.

[freebeard]

None of that can compete with electric motors, and a generation from now, 'pistons' will be studied in history books.

What's happening right now is that [electric] automotive HVAC (heat pump and 'octovalve') is migrating back to housing construction.

How's your dome house going? Have you considered a Nissan Leaf heat pump?

[aerohead]

Originally Posted by freebeard

What's happening right now is that [electric] automotive HVAC (heat pump and 'octovalve') is migrating back to housing construction.

How's your dome house going? Have you considered a Nissan Leaf heat pump?

The house has been dead in the water since 1983. There were some women involved, aerodynamics, and EcoModder.com since 2007.
I'm very interested in the heat pump. Any SEER ratings on that rascal?