AeroBlade,Aston Martin DB11

[aerohead]

'was culling through my magazines and ran across this.I couldn't find a thread on it at EcoModder.
I GOOGLED it and found this article
Aston Martin clears the air on new DB11's 'AeroBlade'

[serialk11r]

So aerohead, are you going to tell us what you think of it?

I have trouble understanding how this influences airflow. There must be a good reason though, because that narrow ducting has got to have some significant pressure drop, limiting the amount of air that actually makes it to the back.

[skyking]

that's nifty. Nice to have a tunnel and the wherewithal to figure out if it helps more than hurts. TANSTAAFL and all....

[kach22i]

Venturi effect?

[botsapper]

Originally Posted by aerohead

'was culling through my magazines and ran across this.I couldn't find a thread on it at EcoModder.
I GOOGLED it and found this article
Aston Martin clears the air on new DB11's 'AeroBlade'

The C-pillar intakes collect and funnel air to special tubing and distributes it on a wide rear exhaust vent behind a pop-up Gurney flap to create a 'virtual spoiler' or a rear deck air curtain. @2:15-3:15.

https://www.youtube.com/watch?v=vvQcGhtSgq0

F1 'black magic' aerodynamicists have been using special ducting (F, W,and S-ducts) to create stall conditions and lowering drag on front wings in max speed straightaways or 'sculpt' blown exhausts under the diffuser to gain more downforce on turns. In aviation, they use blown-flap systems to create higher lift in slow speed conditions. They use blown air vented broadly over the rear upper edge of extended flaps. Just like aircraft mechanics' concerns, they will require more maintenance and have duct blockage & rear deck drainage problems.

[aerohead]

Originally Posted by serialk11r

So aerohead, are you going to tell us what you think of it?

I have trouble understanding how this influences airflow. There must be a good reason though, because that narrow ducting has got to have some significant pressure drop, limiting the amount of air that actually makes it to the back.

*I'm not sure what to think since they refuse to tell us anything specific about it's performance.
*In one photo they show a smooth deck with zero excrescence.
*In the cutaway image,they show ductwork leading to a blown slot directly behind an exposed, modified, Gurney flap,with the air making a right-angled turn.
*Whatever performance the slot provides,it's not enough,so they add a small wing to augment it.
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One thing that's mentioned about modern high performance cars,is,that any drag reduction allows smaller,lighter,radiators to be used,which improves the power to weight ratio.

[aerohead]

Originally Posted by kach22i

Venturi effect?

I think that it is kinda like one.The duct contracts,accelerating the air velocity.If it emerges from the body at higher than ambient velocity it will induce the surrounding air to accelerate and mix with it.
It's quite a bit like Dyson's fan blade-less fan's Coanda nozzle.

[freebeard]

I concur with Coanda-like. A true Coanda nozzle would be pointed rearward, not upward.The convergent duct is tetrahedronal in shape, shrinking from a vertical slot to horizontal.

But exhausting directly behind the Gurney flap is (iffen it works) pure genius. And I don't see a problem with the ducting. VW Squarebacks have an air intake that goes in, down, back, in to the center, and finally forward through a rubber bellow to the intake fan. The fenders are plenums and the rear apron is a duct. It all sees to work.