Plate Hubcaps - Fuel Economy, Hypermiling, EcoModding News and Forum

Nerys · 05-07-2008, 11:41 PM

OK I am going to build some ultra light carbon aero hubcaps. I have several questions I got some hubcaps for 98cents a pop so I got all 5 and plan to cut them up for some plate caps.

Stock they will be recessed slightly. this aerodynamically is going to create a pressure gradient. Do I need to worry about this? or is the drag hit from this too tiny to bother with? If I offset and enlarge the hub caps to alleviate most of this but I am concerned about tire flex pushing off the hubcaps if I do this since to cover that gap I will have to overlap rubber.

Suggestions?

Nerys · 05-08-2008, 01:44 AM

I thought you might grow some civility.

Anyway in a rocket massing a few pounds EVERYTHING matters. DUST in the paint can sap 50feet on your peak altitude costing you the prize. Mass is also not much an issue with rocketry because we are almost ALWAYS below optimal mass so we tend to ass mass via paint to close in on optimal and have a cleaner finish (while we design the rockets we are limited by commercially available engines so we optimize for the engines)

I KNOW aerodynamically flat is better. I also know the edge of hubcaps are slight recessed. If you had read my post you would know this.

What I DO NOT know is how much tire flex there is near the rim. This will determine HOW close to flat I can make them and therefore HOW much of the pressure gradient I can eliminate. Tire flex also has NOTHING to do with aerodynamics.

Nerys · 05-08-2008, 04:05 AM

Once again you show a lack of reading skills. I was pretty clear on the rockets I make as is every link I provide :-)

I have built rockets that have exceeded mach 2 hit 9000 feet (looking to bust 10k this summer its just a matter of money for a large enough engine :-)

I build Rocket Gliders that can hit 200mph on lift off though a typical RG does not go over 100mph on boost otherwise your just wasting newtons pushing air.

I actually went to Virginia Tech for aerospace engineering and decided its not what I want to do.

Chris D. · 05-08-2008, 04:28 AM

Frank, you crack me up man.. lol

Nerys · 05-08-2008, 02:57 PM

http://www.nerys.com/

yeah guess you never bothered to go there ehh.

Riiiiiight.

COMP · 05-08-2008, 03:00 PM

what about moon disc's ???

Nerys · 05-08-2008, 03:26 PM

Well they would "protrude" into the air stream increasing drag (more frontal area now) you definitely want to stay within the dimensions of the tire itself. Here is a drawing to clarify this.

http://www.nerys.com/stuff/aeromod3.gif

COMP · 05-08-2008, 03:29 PM

the one's i have had where behind/lower than the sidewall
add,, they where on RWD rim's

Chris D. · 05-08-2008, 03:41 PM

Quote:

Originally Posted by Nerys

Well they would "protrude" into the air stream increasing drag (more frontal area now) you definitely want to stay within the dimensions of the tire itself. Here is a drawing to clarify this.

http://www.nerys.com/stuff/aeromod3.gif

A vast majority of people stated they saw no gain or
loss by doing this mod to kill off drag so I didn't bother..

Although I will do this to my trucks 15" steel wheels for
winter time to keep some of the snog off my brakes

You mite be iverengeneering somethign that wont get you results..
Build some wheels skirts or something.. underbelly pan, ect..

Is your van the 3.0 Mitsubishi or the 3.3 Chrysler?