Aero front license plate

[Bruce]

My state requires a front license plate.

Anybody ever try to make one aerodynamic, or is it worth the bother? I was thinking that cutting a section from an old blow-molded skylight to fit the contours of the front end would give a pretty good result, but I haven't tried it yet.

I could probably find a skylight for free, but I'm on a super-tight budget otherwise and there are too many variables in my area (hills, temperature, traffic) to conduct effective A/B testing.

[onegammyleg]

Some WRC rally cars hinge them at the top so they blow up at speed.

[Silveredwings]

Originally Posted by onegammyleg

Some WRC rally cars hinge them at the top so they blow up at speed.

I did that with a Miata I used to have.

[cfg83]

Hello -

I have a master plan for this that I haven't implemented. At Home Depot, I found some house address stickers that have the same size/color/background reflectance as my California license plate. I intend to remove the plate and put it in the dashboard like all the rice-rocketeers, and put the address numbers/letters on the bumper. The letters on the bumper will have a "long rectangular" European look.

This way I will be complying with the spirit of the law (a license number that is easy to read day or night on the *bumper* of the car).

When I was fiddling with different grill block designs, I thought of it. See second and third pictures below :



CarloSW2

[Bruce]

The presence or absence of a license plate would definitely make an aerodynamic difference in my case, because the license plate blocks the radiator openings...FE would be lower if I removed it.

[red91sit]

Originally Posted by Bruce

The presence or absence of a license plate would definitely make an aerodynamic difference in my case, because the license plate blocks the radiator openings...FE would be lower if I removed it.

You could put it directly onto your grill block

[Ryland]

You should really check your state law befor doing anything to your license plate, alot of states require that NOTHING be placed in front of the lisence plate numbers or experation stickers, this includes solid or clear covers.
you might be able to get away with forming your plate to fit your bumper better, but if your plate is not clearly readible unmolested exspect to get a ticket.
I left mine in the stock location as the bumper is pretty flat there, but really, if I lowered it a little it would fit right in to the grill block.

[86Celica]

Originally Posted by theclencher

If the airflow remains attached around the front of the car a flat license plate won't make any difference in aero. I suppose a total flush mount system would look neat and make you feel good but it won't make any quantifiable aero improvement on most car front ends.

I think it does make a difference. Imagine an air molecule hitting the front license plate, it has to be pushed aside with a 90-degree angle, which costs energy. If the angle is lower (as with a rounded plate), less energy is needed to push the air molecule aside - or in other words, the pressure on the license plate is less (check those graphical representations of pressure around a vehicle, it's main high pressure/red areas are on the front end of the vehicle where the air hits straight on). It's like with a windscreen, the lower the angle the better.
Also, with a 'rounded' licence plate the air will remain attached better than with a straight plate.

To avoid troubles with the law perhaps it's possible to beat the license plate with a hammer into a slightly rounded shape.

[Bruce]

That's probably the best solution, and it's a heck of a lot easier to do.

I don't have a mount like cfq83 -- just a couple of holes in the bumper for the screws -- so I should be able to form it to fit pretty easily.

I doubt the cops would have a problem with a bent plate. A lot of front plates around here have big dents in them from people running into things.

Thanks!

[lunarhighway]

i'm curently design a cover plate for a depression in my front bumper that will fair the licence plate into the bumper. legally i can't do much to the shape of the plate so i have to work with the space around it


this is what it should look like when finished (also note the grill cover that curently is only tape...the 2 top rows are closed on the back anyway!, and the airdam extention that shouldn't be to hard to make once i find a suitable material):


my initial idea was to just cover the depression, but since the licence plate is in front of it i decided to design the cover so that it would make a smooth transition between the edges of the licence plate and the lines of my bumper.

i doubt this mod will produce any measurable gains but i don't think it will hurt either.

[red91sit]

Originally Posted by lunarhighway

i'm curently design a cover plate for a depression in my front bumper that will fair the licence plate into the bumper. legally i can't do much to the shape of the plate so i have to work with the space around it


this is what it should look like when finished (also note the grill cover that curently is only tape...the 2 top rows are closed on the back anyway!, and the airdam extention that shouldn't be to hard to make once i find a suitable material):


my initial idea was to just cover the depression, but since the licence plate is in front of it i decided to design the cover so that it would make a smooth transition between the edges of the licence plate and the lines of my bumper.

i doubt this mod will produce any measurable gains but i don't think it will hurt either.

Looks liek some good ideas here! Not to mention a very inteseting little Opel

The air dam extension might not be such a good idea though, I would rather see you add an underbody that slopes down to the lowest points of the undercarriage.

[lunarhighway]

Originally Posted by red91sit

The air dam extension might not be such a good idea though, I would rather see you add an underbody that slopes down to the lowest points of the undercarriage.

are there any arguments directly against the airdam extention? i would like to make such a modification as you mention, but it would present a lot of practical obstacles. i might eventually consider something more radical but while i contemplate if and what i can add, if a simple strip could reduce drag in the area even slightly it would be better than nothing.... unless of course it would somehow have a negative influence i'm overlooking?

back to the topic of lisence plate fairings here's some images of what i'm working on: last night i made a carboard mock up of how the plate should bend...
most likely i'll make it out of some thin metal plate that will be bended into the right shape and painted.

what it should become:
http://i77.photobucket.com/albums/j5...tski/plate.jpg
the plan:
http://i77.photobucket.com/albums/j5...i/DSC01341.jpg
mock up of the shape for the corners of the bended plate:

http://i77.photobucket.com/albums/j5...i/DSC01351.jpg
http://i77.photobucket.com/albums/j5...i/DSC01345.jpg
http://i77.photobucket.com/albums/j5...i/DSC01348.jpg
http://i77.photobucket.com/albums/j5...i/DSC01347.jpg
the next step will be to match the shape to the car and if everything aligns i'll build a template. and hopefully soon something i can test in practice.

[red91sit]

Very nice cardboard mockups!!! but adding the lip can increase frontal area with no appreciable effects on drag. The only real benefit of the lip is having less air going under the car, but it still has to get out of the way so more is directed over and around. It can also deflect air away from high drag places, but this takes a lot of energy too haha. so no real gain there.

Underbodies are FAR more effective, giving noticeable increases, them and grill blocks. An aero bumper would have nearly no effect.