grill "shield" rather than block?

[aerohead]

Originally Posted by lunarhighway

that's the sort of thing i'm looking for....you wouldn't by any chance have a picture off this setup? i've been looking for images of stalling wings for inspiration but a totally different leading edge would be needed for the sort of separation a grill would require.

i assume some premium carmakers comming out with low drag cars secretly employ these tricks to arrive at such a low Cd with quite large grills

lunarhighway,I should have a two-color image of Ford's grill.I'll see about locating it and getting it scanned and posted.I couldn't find it with my materials here at ecomodder,and I believe someone posted it at maxmpg a few years back,a site which is no longer active.

[lunarhighway]

thanks, that would be realy nice... thus far google hasn't turned up much interesting pictures... i suppose the actual grill might not be all that shocking but if some plain pieces are set at the right angles and spaceing etc they might help aero in ways something that looks "about the same" couldn't

[elhigh]

I've been wondering about an extended nose. The front of my truck is pretty flat - not 1986 Ford F150 flat, but a bluff bow to be sure. Adding some nosecone would bring the airflow up smoothly over the front.

There's enough acreage of airspace underneath to get cooling air from under the car.

I've been thinking about radiators too - and I have this forum to thank for that. Why does the radiator have to be the big, flat panel? What if the radiator were a duct filled with tubes and fins, shaped something like the A-coil in your home air conditioner? Have the circulator fan be a vanaxial blower at the apex of the A, pulling in from the front and blowing down and out at the A's rear leg. This would negate the need for a forward-facing air inlet at all, all the air would come in from below the front of the car.

[PaleMelanesian]

[lunarhighway]

that's sort of what they did to the Plymouth SuperBird... back than the front end of any car was basically flat.

you could go pretty low with the nose and than add an airdam to scoop up air into the original grill should that be needed the additional advantage is that you could leave the "grill" area onaffected so you don't risk overheating, but the aerodynamif profile will change drasticly when the vehicles moving.

[2000mc]

sorry if i'm beating a dead horse, but it doesnt make sense (atleast to me) that you would have enough airflow to cool while driving but not at idle.

have you visually checked that the fan is spinning when it should? not just making noise?

with the hood open, and the fan running, does the fan produce a strong hot blast of air?which would be normal

is the air flow weak, and extremely hot? this would be expected if the there was very little airflow due to the grill opening or a weak fan.

or is it a strong blast of fairly cool air? could be caused by partially blocked radiator, or coolant not circulating at low rpm due to low coolant level

hold your hand infront of the grill opening with the fan running. assuming everything else is functionng normally, and the problem is the grill opening size, you should be able to feel alot of air moving. if the grill opening is the restriction, i'd think it would feel a little like holding your hand infront of a vacuum.

[lunarhighway]

when the car's at speed the high pressure area in front of it forces air trough the grill and the radiator, and to a lesser extend some suction underneath the car, gets the air out of the engine bay... but when it's static or at slow speed this airflow needs to be forced by the fan... and a fan basically just moves air... it doesn't create a real pressure difference...
the fan in the car is made to move air trough the original opening and trough the radiator, but if this openig is reduced by lets say 50% your fan would have to be 50% stronger in simple terms... since the grill is calculated for a worst case scenario ,under normal conditions it's to big, so partly blocking it will still deliver enough air to the rad to keep things withing normal parameters.

this is also the reason why some sportsplanes tend to overheat while when they're taxing.
their rads are relatively small and placed in housings designed to deliver the right airflow at the average speed the plane will travel... on the ground there's not enough airflow trough the radcore and things can get to hot.

[aerohead]

Originally Posted by lunarhighway

thanks, that would be realy nice... thus far google hasn't turned up much interesting pictures... i suppose the actual grill might not be all that shocking but if some plain pieces are set at the right angles and spaceing etc they might help aero in ways something that looks "about the same" couldn't

lunarhighway,I located the article(s) on the grille I remembered.My memory isn't what I think it is,so here's some corrections: The original article appeared in the July 1976 issue of POPULAR SCIENCE,page 60.------------------------------- The "lamellar" grille was developed by Ford of Cologne,Germany.It appeared on an experimental Ford Capri.The grille cut drag by 12% and cut lift by 30%.-------------------------------------------------------------------- The grille is comprised of five ( 5 ) horizontal airfoil sections,layed back at a 21-degree angle,and each airfoil element is configured "nose-down",with the cord line of the highly cambered foils angled,tail-up,at 30-degrees.----------------------------------------------------------- At low speeds,there is no boundary layer effects,and the air goes through unimpeded.At an undisclosed speed above "moderate",the boundary layer thickens and stalling takes place,with the stalled region acting as a barrier to flow.----------------------------------------------------------------- The grille showed up in the 1978 Capri III,Ford Fiesta,and Ford Granada.The grille was "de-raked" and is vertical rather than angled back,and it's performance deteriorated.--------------------------------------------- On the third gen Capri,the lamellar grille,along with a front airdam is only good for a 6 % drag reduction,unlike the 12 % reduction with the original grille by itself in 1976.--------------------------------------------------------- I attempted to "join" Photobucket,so I could post the photo and it seized the computer and we had to shut-down and re-boot the computer to get rid of it.------------------------------------------------------------------ If anyone can recommend an alternate hosting site,I'll try that.In the meantime,if you'll send me a PM here at ecomodder,I'll either try and scan and email the image,or mail it to you the old way.------------------------------------------------------------------ It looks like this type of grille technology is very finicky,and might require a windtunnel to set up.

[cfg83]

aerohead -

Assuming for the moment that you have Windows XP, you can use MSPaint to make the image smaller (If I remember correctly, I don't think this will work for Windows 95 because MSPaint doesn't store JPEG files) :

Start 
  -> Run... 
    -> type "mspaint" in the "Open:" box
      -> click "OK"
File  
  -> Open... (browse to file and double-click it)
Image 
  -> Stretch/Skew... 
    -> change the percent in the "Horizontal" and "Vertical" 
       to be something like 50%
File  
  -> Save As... 
    -> Save as DIFFERENT file name, or you will lose your 
       original.  Make sure the "Save As Type" is set to 
       JPEG for maximum compression.

Check if the file is below ~110,000 bytes. If yes, then you can upload it to this forum. If no, then you will have to repeat the process until the file is small enough.

CarloSW2

[Frank Lee]

That grille aerohead is talking about was used on the 1st gen Tempos. At least, I dimly recall reading that one time.