Making the Ioniq slippier

[Phase]

Originally Posted by aerohead

ABS is just a 'diaphragm.' It has no strength to speak of.
Typically, it's vacuum-thermo-formed over some tooling which either creates 'ribs', or compound-curve 'egging' to resist deformation. Its natural frequency must never be experienced while in service.
Aeroelasticity would be a real thing at 80-mph!
The pieces of car bellies I find laying in intersections with 'dips' all have a fiberglass pre-form embedded within the sheet-plastic matrix. They aren't 'flat.' Always 'curves', or 'fins', 'ribs', or submerged NACA inlets molded in as stiffening 'corrugations.'
Coroplast or sheet metal might be better for underneath. And with a bonded reinforcing structure behind them.
Lots of examples here and elsewhere.

Well Julian Edgar suggests abs for the underbelly with a steel skeleton frame welded into it so it holds shape. So that was the route I was looking into. Not just pure wobbly abs or acrylic by itself

[Phase]

Originally Posted by aerohead

1) Aero drag would fall off a bit with lower air density. ( Raw barometer and ambient conditions can be input'd into online air density calculators) AWOS from a local airport won't help you, as the barometric pressure they report is already 'fudged' for the pilots.
--------------------------------------------------------------------------------------
2) The Air Conditioner will be working overtime. AC blower fan will probably be on 'HIGH.' Radiator shutters will be wide-open, with a Cd 0.005-.007 penalty. Condenser electric fans may be pulling full current in traffic or stops. The IONIQ should be designed for 122-F operation ( Furnace Creek, Death Valley, California ).
--------------------------------------------------------------------------------------
3) There can be significant 'weather' during summer. Strong wind spectra. All directions, depending.
--------------------------------------------------------------------------------------
4) Hot asphalt pavement may have tire tread-blocks 'squirming' with extra hysteresis loss as they roll, with potential R-R penalty. ( GM designs for 220-F tire temps, with sidewalls @ 10-F over ambient )
------------------------------------------------------------------------------------
5) The gasoline itself has an API, thermal coefficient of expansion. 'Cold' fuel dispensed into the tank will 'grow' as you drive, with infrared forcing from the hot roadway. The mass air sensor will track air density, but I'm unsure of fuel. If you're doing 'tank-mpg' backup, technically, this would have to be tracked and accounted for ( why universities use 'mass' not 'volume ).
Some stations will be able to provide actual storage tank temperatures, whether below, or above ground. Just ask. If not, something like a Wexler, 8-inch, stainless steel stem thermometer can be placed directly in the filler neck as you refuel. It's what I've done.

Idk if you saw my other thread post, but I mentioned having xpel xr plus super nano ceramic 1300 dollar window tints all around the car. I never have to put the fan speed on high, even when it’s 120 degrees outside in Phoenix. Usually fan speed is lowest setting. Maybe 2 bars of fan speed if I’m driving direct into the sun in the afternoon. I also have thermal jute heat shield insulated installed all around the car from second skin. It keeps heat out in summer and keeps the heat in during winter. Also slightly reduces cabin and road noise

[aerohead]

Originally Posted by Phase

Well Julian Edgar suggests abs for the underbelly with a steel skeleton frame welded into it so it holds shape. So that was the route I was looking into. Not just pure wobbly abs or acrylic by itself

Julian's belly is a work of art! If he spec'd the thickness that he used, we know it'll hold up at Australian speed limits.
At 80-mph, though, you'd be in a different kettle of fish.
Remember, aerodynamic forces vary as the square of the velocity.
By increasing speed, from, say 55-mph, to 80-mph, aero forces, stresses, and strains will increase by more than twice! Perhaps requiring shorter spans between supports.

[Phase]

Originally Posted by aerohead

Julian's belly is a work of art! If he spec'd the thickness that he used, we know it'll hold up at Australian speed limits.
At 80-mph, though, you'd be in a different kettle of fish.
Remember, aerodynamic forces vary as the square of the velocity.
By increasing speed, from, say 55-mph, to 80-mph, aero forces, stresses, and strains will increase by more than twice! Perhaps requiring shorter spans between supports.

He said 2 or 3mm abs thickness. Aluminum sheets are really wobbly. Worse than abs. I was at home depot checking out different materials. Steel was solid, but geez I didn’t realize it was that heavy!!!! No possibly way I could do a steel underbelly

[aerohead]

Originally Posted by Phase

He said 2 or 3mm abs thickness. Aluminum sheets are really wobbly. Worse than abs. I was at home depot checking out different materials. Steel was solid, but geez I didn’t realize it was that heavy!!!! No possibly way I could do a steel underbelly

All I've found there was rolls of 24-inch-wide flashing, in the roofing section.
It could be used on 'curves', with formers, stringers, and hat-section bonded or riveted to the inside surface, otherwise, it would be way too flimsy.
We have a few metal recycling centers which still allow salvage.
Retired, commercial, aluminum signs sometimes show up, and the material is thick enough to span 24" between supports. The diffuser on the truck is a single piece, with t-section pop-riveted on the backside.

[Phase]

Originally Posted by aerohead

All I've found there was rolls of 24-inch-wide flashing, in the roofing section.
It could be used on 'curves', with formers, stringers, and hat-section bonded or riveted to the inside surface, otherwise, it would be way too flimsy.
We have a few metal recycling centers which still allow salvage.
Retired, commercial, aluminum signs sometimes show up, and the material is thick enough to span 24" between supports. The diffuser on the truck is a single piece, with t-section pop-riveted on the backside.

I mean I could always use true carbon fiber. Just kidding. That stuff would be great but extremely expensive and would outweigh any gas savings. Julian is always saying to avoid coroplast though because it can’t handle impact as well and it won’t stand up to the heat from the muffler and exhaust

Also related to temperature earlier, the engine seems to be happier and the hybrid battery loves warmer weather. It’ll run on ev mode much easier around the city too when it’s warmer. So besides aero benefits of thinner air, the hybrid system loves it!

Did you see my wheel cover picture?

[aerohead]

I think you mean wheel 'skirt'.( wheel cover would be on the wheel itself ).
And yes I did.
The 'flatness' will need reinforcement.
Yard sale, cheap, carbon-fiber arrow shafts, bonded to the inside of the skirts would take all the 'shake' out of them. They're narrow and don't take up a lot of clearance space.

[Phase]

Originally Posted by aerohead

I think you mean wheel 'skirt'.( wheel cover would be on the wheel itself ).
And yes I did.
The 'flatness' will need reinforcement.
Yard sale, cheap, carbon-fiber arrow shafts, bonded to the inside of the skirts would take all the 'shake' out of them. They're narrow and don't take up a lot of clearance space.

im actually going to have to add a slight curve for the lower half of the skirts for clearance. the posterboard was actually touching the tires in this picture

how much clearance should i allow from the tire itself? about a full inch? can i bend the arrows smoothly without snapping them?

[freebeard]

No possibly way I could do a steel underbelly
....
I mean I could always use true carbon fiber. Just kidding.

Flat is what Polymetal et al do best. If you need a molded shape how about vulcanized fiber?

1513 Plastic From Paper

Cut your fender skirts out of Dish satellite dishes.

[Phase]

Originally Posted by freebeard

Flat is what Polymetal et al do best. If you need a molded shape how about vulcanized fiber?

Cut your fender skirts out of Dish satellite dishes.

how would i get zinc chloride or even old dish satellites? for the wheel skirts though i was thinking of aluminum sheet with a skeleton frame backing, like carbon fiber arrows mentioned with a light bend