Making the Ioniq slippier

[aerohead]

Originally Posted by Phase

Any benefits of extending rear spoiler like this? Horrible mock up shape obviously. But foot long extension should help a little right?

1) My opinion is that, it would increase drag.
2) Presently, the IONIQ rear spoiler just 'fits' at the boundary of the 2013, Aerodynamic Streamlining Template-III.
3) If you want to extend it, I'd recommend you follow Tesla's lead on their Model X.
4) At its debut, the Tesla Model X featured a 3-position, automatic rear spoiler, which rose up from behind the backlight.
5) At it's lowest drag setting, the spoiler was 'up' at the leading edge, and tilted downwards from there, with it's upper surface mimicking the contour of the 'Template', to the spoiler's trailing edge. This spoiler had freezing issues in 'Four-Season' environments, and was 'silently' retired from production.
6) If you've grabbed a 'blueprint' of your car by now, you could fit it under the 'Template' tool here at the Aero Forum, to inspect the angle I'm referring to.
7) If you want to compare the Aero 2002, Probe-V, VW H2 concept, M-B Boxfish, Chevy Volt-I, Ford EVOS concept, Jaguar C-X75 concept, Renault EOLAB, Tesla Model X, GAC ENO.146, LIGHTYEAR One, Mercedes-Benz IAA and EQXX extended tails to the 'Template', you'll find that they are exact fits.
8) It's what I recommend, short of spending hundreds of thousand of dollars at a wind tunnel.

[aerohead]

Originally Posted by Phase

So long story short, extending the spoiler works?

1) It's 'conditional.'
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2) At Bonneville, many cars are 'traction-challenged.'
3) Even at the end of the race course, cars are easily capable of spinning their rear tires.
4) The Chevrolet Corvette LT1, which was ahead of me at the wind tunnel raced the next day. I was at the finish line when he came by, got sideways, lifted twelve-feet into the air, performed a half-gainer, landing on his roof at 210-mph. The car was toast. The driver okay, but visibly shaken.
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5) The Bonneville spoiler is a two-fold 'safety' device.
A) The capping plates add some 'skeg' / 'rudder' aerodynamic 'mass', and in the onset of yaw, help 'weathervane' the car back, straight down the course.
B) The 'deck' of the spoiler can / may, reduce turbulence by re-attaching separated flow, allowing the arresting parachutes to be submerged in 'clean' air ( also an 'anti-yaw' provision should the car begin to go sideways).
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6) The 2008 Ford Fusion 999 Hydrogen Fuel Cell land speed record car began @ Cd 0.34, and by the time the team got though with it, it was down to Cd 0.21.
A 'Bonneville spoiler' was part of the kit, but it extended out no further than the 2013 AST-III contour. Just like Hyundai's Prophecy concept car, Shelby Cobra Daytona Coupe, 1969 Pontiac Firebird Trans Am, Ital Design Medusa, 1982 Pontiac Trans Am, 1985 Renault ALPINE V-6, 1988 Lotus Esprit Turbo, 1990 Opel Calibra, Ferrari 360 Modena, Volvo ECC, Dodge Viper Defender, Ferrari F355 Berlinetta, Porsche 911 GT1 ( LeMans , sans wing ), Dodge Viper GTS, Nissan 200SX, Toyota MR2, Alfa Romeo 8C Competizione, Nissan 370-Z, Honda Accord Crosstour, Subaru/ SCION BRZ/ F..., 2014 Audi RS5, 2014 Chevy Camaro SS 1LE, 2015 ACURA NSX, Alfa Romeo 4C, 2015, LEXUS RCF, 2016 Porsche 911 GT3 RS ( w/o wing ), 2017 Porsche 911 Turbo S, KIA Stinger GT, Toyota GR Supra, to mention some.

[Phase]

Originally Posted by aerohead

1) It's 'conditional.'
--------------------------------------------------------------------------------------
2) At Bonneville, many cars are 'traction-challenged.'
3) Even at the end of the race course, cars are easily capable of spinning their rear tires.
4) The Chevrolet Corvette LT1, which was ahead of me at the wind tunnel raced the next day. I was at the finish line when he came by, got sideways, lifted twelve-feet into the air, performed a half-gainer, landing on his roof at 210-mph. The car was toast. The driver okay, but visibly shaken.
--------------------------------------------------------------------------------------
5) The Bonneville spoiler is a two-fold 'safety' device.
A) The capping plates add some 'skeg' / 'rudder' aerodynamic 'mass', and in the onset of yaw, help 'weathervane' the car back, straight down the course.
B) The 'deck' of the spoiler can / may, reduce turbulence by re-attaching separated flow, allowing the arresting parachutes to be submerged in 'clean' air ( also an 'anti-yaw' provision should the car begin to go sideways).
--------------------------------------------------------------------------------------
6) The 2008 Ford Fusion 999 Hydrogen Fuel Cell land speed record car began @ Cd 0.34, and by the time the team got though with it, it was down to Cd 0.21.
A 'Bonneville spoiler' was part of the kit, but it extended out no further than the 2013 AST-III contour. Just like Hyundai's Prophecy concept car, Shelby Cobra Daytona Coupe, 1969 Pontiac Firebird Trans Am, Ital Design Medusa, 1982 Pontiac Trans Am, 1985 Renault ALPINE V-6, 1988 Lotus Esprit Turbo, 1990 Opel Calibra, Ferrari 360 Modena, Volvo ECC, Dodge Viper Defender, Ferrari F355 Berlinetta, Porsche 911 GT1 ( LeMans , sans wing ), Dodge Viper GTS, Nissan 200SX, Toyota MR2, Alfa Romeo 8C Competizione, Nissan 370-Z, Honda Accord Crosstour, Subaru/ SCION BRZ/ F..., 2014 Audi RS5, 2014 Chevy Camaro SS 1LE, 2015 ACURA NSX, Alfa Romeo 4C, 2015, LEXUS RCF, 2016 Porsche 911 GT3 RS ( w/o wing ), 2017 Porsche 911 Turbo S, KIA Stinger GT, Toyota GR Supra, to mention some.

So you’re saying angle the spoiler slightly down versus straight out and to continue the aero template shape?

[aerohead]

Originally Posted by Phase

So you’re saying angle the spoiler slightly down versus straight out and to continue the aero template shape?

Yes. You'd basically just elongate the upper profile along the path shown, which IS at a downward angle / curvature.
The fact that, so many of the current lowest-drag bodies incorporate this contour, lends credence to the science from which it originates.
As a 'first-approximation' for a 'solution' to lower drag, I've seen nothing published since 1974 which could exceed the probability for success.
The 'form' is essentially 'pre-tested.' 'Pre-measured.'
The kinds of pressures and velocities associated with drag reduction that you might measure for, are already incorporated within the 'shape.' It works.
The sides of the car would follow an elongated path, no more aggressive than that of the upper surface.
Diffusers are harder to call, as, with the exception of the VW XL1, there are very few detailed views for vehicle underbodies, which would define what's underneath, and how we'd improve it.

[freebeard]

As a 'first-approximation' for a 'solution' to lower drag,

I feel that my work here is not in vain.

[aerohead]

Originally Posted by freebeard

I feel that my work here is not in vain.

All the comments have helped.
And, probably, most of all, reading Richard Feynman.
He could always tell what the answer was going to look like, and could explain why.
He would ask questions in the neighborhood of the problem.
He knew it was impossible for his team to obey a bunch of rules unless they understood how things worked.
He understood un-understandable.
He knew things from instinct and experience.
He refused to participate in multidisciplinary dialogue. ( A great problem for me, and why I'm learning to walk away.
He made phenomenological adjustments to constants.
When he chose not to buckle down to the System, he was prepared to pay the consequences if it didn't work.
He explained what he was doing.
He published things whichever way they came out.
He published 'all' the results.
He repeated experiments of others.
Then he'd know any real differences.
He could solve $billion arguments with a glass of ice-water and a rubber o-ring.

[Phase]

heres a rear underbody picture of the ioniq someone got on the ioniq forum

[Phase]

[freebeard]

aerohead -- That's fine, man.

For the angle of the not-spoiler, look to that Mercedes Benz concept with the retractable boxed cavity.


https://i.imgur.com/W8TA6tA.jpeg

edit:
Whoops! I guess it's this Toyota patent from 2016


http://www.autoguide.com/auto-news/2...-car-tail.html

[aerohead]

Quite the torture chamber!
An interesting challenge.
1) Any existing holes can become anchor points by sandwiching oversized fender washers on each side of the hole, captured there when the fastener is snugged.
2) Heat-wrap would help contain the infrared.
3) Extra heat-shields with air-gaps.
4) Partial perforation of panels nearest the heat source if necessary.
5) Forward narrow panel, all-metal.
6) One-piece behind, to the rear suspension lower arms.
7) The lower arms themselves could carry their own 'moving' belly panels.
8) Behind those, a single-piece panel with diffuser.
9) Urethane-rubber floor mat material to close gaps.
Just thinking out loud.