Random Student Cars - Shell Eco and Others

[kach22i]

I think that we have pretty much acknowledged that many of these one off prototypes are not suitable road cars and are in a category of their own.

We have admired many of them, and some of them let's face it are weird or challenge what we accept as good aerodynamics.

I've looked at many photos of the car below, they seem very protective of showing off a very unique feature, the spoon-like dimple behind the operator's head.

How does it work, what does it do, so on and so forth.

I have a few theories but want to hear from you guys first to verify my suspicions.

Team ARMZ STAR
Designing and fabrication of light-weight car
https://www.transplo.com/PK/Sahiwal/...9032/ARMZ-STAR

28/07/2015

ALHAMDULILLAH Team ARMZ STAR has passed phase 1 registration for SHELL ECO 16.

More photos:
https://www.dawn.com/news/1157522

[kach22i]

My analysis of the "Rush":

1. Leaves a sizable hole in the air with that big boxy rear end.

2. May be inducing lift at the front with the front chin spoiler section.

3. The roof spoon dimple might be Porsche 917 inspired. I want to think the detachment of air at the high point creates a vortex that is to their advantage somehow. I want to think it is that thought out and not a remnant of picking up a wet clay model and leaving a big thumb print in the roof then deciding it "looks good" and we don't have time to fix it before the teacher gets here.

I do like that it is different from so many other entries, and that roof canopy may have application in pick-up truck design, just to say something nice.

[freebeard]

Boxed cavity?

[kach22i]

Originally Posted by freebeard

Boxed cavity?

Yes, I guess so, a box cavity has the ground plane to play off of, and this has it's pick-up truck like rear deck.

We my have touched on this once before in discussion of the Prius roof, Viper coupe roof and others. We determined then that it was for ease of entry headroom and not much else.

This would not be the case of the "Rush".

Another double bubble sports car roof below.

New Supra?
https://jalopnik.com/are-the-toyota-...new-1789423366


If I were to label the Rush roof, it would be "separation point containment".

Where the side vanes contain an air pressure pocket that the air farther above moves over. More akin to the half cover on a pick-up truck.

https://www.google.com/url?sa=i&rct=...43591515610942



https://www.google.com/url?sa=i&rct=...43591515610942


Contain the air pocket, and you prevent it from spilling over the sides and creating a vortex via the differing air pressures of air flowing past the car's body.

You still have detachment of roof air and the drag or resistance between the two bodies of air so I do not see this as superior to maintaining attachment, it is just not as terrible as it looks at first.

It is a side canopy box cavity (buttress/vane) open to the top "separation point containment" indentation.

"Spoon Roof".

[Vman455]

In the original Viper GTS, the double bubble was to keep the roof low but allow for the use of helmets (I'm 5'11", and just barely cleared the headliner with a helmet on). The 86 and new Supra have similar roof designs, probably for the same reason. The Prius, not so much.

[kach22i]

Originally Posted by Vman455

In the original Viper GTS, the double bubble was to keep the roof low but allow for the use of helmets (I'm 5'11", and just barely cleared the headliner with a helmet on). The 86 and new Supra have similar roof designs, probably for the same reason. The Prius, not so much.

That sounds reasonable.

Picture a pitcher of water being poured on the roof of a double bubble car.

That water is going to funnel towards the middle and down the roof just like air flow does, right?

A double bubble roof just might make a rear spoiler more effective.

In the case of the Rush car in the first post, why create a vortex or trapped air pocket just to have air flow over it?

If they have plans to scale up this model and have a rear window or do a pick-up truck version, then it makes some sense.

[euromodder]

more pics in FB vid
Apparently not spoon shaped

https://www.facebook.com/ARMZ.STAR/v...7032712103226/

[Frank Lee]

They want twin trailing vortices off the roof.

[kach22i]

Originally Posted by euromodder

more pics in FB vid
Apparently not spoon shaped

https://www.facebook.com/ARMZ.STAR/v...7032712103226/

Computer illustrations show more of a Vee trough but once they fluted the creases it is a spoon for lack of better description. See photos far below.

Thanks for posting that link, many new views in it.

Originally Posted by Frank Lee

They want twin trailing vortices off the roof.

I suspect they intend the vortices to swirl inward and into the trough where it is contained by the air above passing over it.

All this takes energy.

However if this buttress method works and gets one a flat rear deck then maybe it can be applied on a different project.

What I see here is a group committed to an efficiency challenge and answering with what is race car looking car, the car they really wanted to build.

So they tried something different, not the end of the world.

From what I've read they have dreams of making this car for the masses, again another non-Shell Eco Challenge criteria.

They designed a small/affordable car that one can load a bunch of stuff on top of that pays homage to one of the best known race cars of all time, the Porsche 917.

Like I said, none of that is in the Shell Eco Challenge outline, but looks like they had some fun.