Lamellar self-blocking grille

[aerohead]

Originally Posted by cfg83

aerohead -



I think so. At first my Dad said "where's the beef?". What I provided to him did not explicitly state that wind tunnel testing was conducted. After we talked, he said that they probably *did* do wind tunnel testing because they *should* have had the facilities to do it. What's really needed is the original academic paper that documented everything. He agreed with another poster that it is hard to tell how accurate the drawing is to the grill as described. It could just be an "artist's rendering" for a magazine that leaves a (devilish) detail out.

I asked and he said you could simplify it to being "just flat slats", but he would not expect it to perform as well.

CarloSW2

In my spare time( what a joke!) I'll go the the SAE website archive and see if maybe Ford presented a paper at that years SAE Congress or Symposium.The auto makers are usually pretty good about doing this sort of thing.We might see an academic paper yet.Good call by your dad.

[cfg83]

aerohead -

Originally Posted by aerohead

In my spare time( what a joke!) I'll go the the SAE website archive and see if maybe Ford presented a paper at that years SAE Congress or Symposium.The auto makers are usually pretty good about doing this sort of thing.We might see an academic paper yet.Good call by your dad.

Thanks. If nothing else, we will be able to confirm the devilish details of the design. He'll be happy to spend time analyzing the paper when you find it.

(Apologies for going off-topic here ...)

He talked a lot about the effect being akin to a "compressor stall" in jet engines :

Compressor stall - Wikipedia, the free encyclopedia

A compressor stall is a situation of abnormal airflow resulting from a stall of the aerofoils within the compressor. Stall is found in dynamic compressors, particularly axial compressors, as used in jet engines and turbochargers for reciprocating engines.

Compressor stalls result in a loss of compressor performance, which can vary in severity from a momentary engine power drop (occurring so quickly it is barely registered on engine instruments) to a complete loss of compression (compressor surge) necessitating a reduction in the fuel flow to the engine.

(Speculation on my part)
In the above explanation, when the jet engine does not reduce the fuel flow, I think you get this very dangerous "backfire" effect :

Flying :

http://www.youtube.com/watch?v=8D5AqAxE330

Idling backward, it looks like fuel is being dumped : [EDIT: Wrong, it's a vortex]

http://www.youtube.com/watch?v=-BnrLCvMgYo&NR=1

CarloSW2

[TomO]

So after looking at the posted article, I looked at the grill on my '03 Odyssey. It has three horizontal bars in the grill that are shaped exactly the same as the airfoil shape in the picture. Maybe this is how the Odyssey achieves its 25MPG highway mileage?

[cmroseberry]

The depictions of the flow that accompany the article are nonsense!

This grille geometry is fine from an efficiency standpoint, but there is nothing miraculous about the way in which it would work.

[aerohead]

Originally Posted by cfg83

aerohead -



Thanks. If nothing else, we will be able to confirm the devilish details of the design. He'll be happy to spend time analyzing the paper when you find it.

(Apologies for going off-topic here ...)

He talked a lot about the effect being akin to a "compressor stall" in jet engines :

Compressor stall - Wikipedia, the free encyclopedia


(Speculation on my part)
In the above explanation, when the jet engine does not reduce the fuel flow, I think you get this very dangerous "backfire" effect :

Flying :

Idling backward, it looks like fuel is being dumped :

CarloSW2

Taxiing to the runway,on our way from Guam to Vietnam,our airliner suffered a compressor stall,blowing a beautiful smoke-ring out the nozzle of the engine on my wing.After a small wait,the pilot came over the intercom,told us about it,and we were shortly on our way to sunny DaNang.Haven't thought about that in years.

[lunarhighway]

on the C-17 just before it backfires there's a small vortex going from the ground into the engine... it's easy to understand why most airfields are inspected very carfully for debris

[aerohead]

Originally Posted by lunarhighway

on the C-17 just before it backfires there's a small vortex going from the ground into the engine... it's easy to understand why most airfields are inspected very carfully for debris

Is that why Soviet fighters used a wingtop engine inlet until transition into flight?

[cfg83]

lunarhighway -

Originally Posted by lunarhighway

on the C-17 just before it backfires there's a small vortex going from the ground into the engine... it's easy to understand why most airfields are inspected very carfully for debris

So that's what that is! :

C-17 Globemaster III - Wikipedia, the free encyclopedia

Boeing C-17 creating a visible vortex while demonstrating the use of reverse thrust to push the aircraft backwards down the runway.

CarloSW2

[cfg83]

Hello -

Could this be an example of a "combo grill"? :

Help with my aero mods: 1.8L 05 Auto Toyota Corolla

Originally Posted by blackjackel

...

This is what the grill looks like unaltered:


...

The shape looks close to the description, but each slat is honeycombed with smaller holes. Maybe the smaller holes "vanish" at higher speeds?!?!?! Probably just more designer poop.

CarloSW2

[lunarhighway]

this might be something similar:


mercedes m class