Elio reverse trike aerodynamics

[brucepick]

The Elio fully enclosed reverse trike is currently slated for production and delivery in summer of 2014.

[EDIT]
As of Jan-Feb 2014 Elio is showing the P4 prototype which has improved aerodynamics. More details at post #26 in this thread. Here's a photo:


[/EDIT]

Based on early photos I thought the body shell to be pretty slippery (not counting the outrigger front wheels). The newer photos here: Elio Motors: Ultra High Mileage Car
show good views of rear quarter and from above. Click tab "Photos" and scroll down.




What do you think? Will the essentially flat rear deck lid cause turbulence?

How about the rounded back end? Is that worse than if they had continued the side taper to the same final total length, with a straight vertical back end?
[EDIT: Apparently Elio found they did hurt; the P4 version lost those drag-inducing features.]

Even so, I would not be surprised to learn this has a very low Cd and CdA.
I think one might build good tails for the front wheel fenders; I suspect they are the area with greatest trailing turbulence and drag.

I'm looking for comments from those here with a good education in fluid dynamics.

[brucepick]

Bump.
I think this reverse trike deserves a look here.

[kach22i]

Originally Posted by brucepick

What do you think?

I think that it's surface area is so small, that it could be shaped like a brick and still be more aerodynamic than 99% of all other road vehicles.

[NeilBlanchard]

The outboard front wheels are the biggest source of drag, probably. The flat deck lid in the back will not be an issue, I don't think.

[brucepick]

Neil,

Thanks. I agree re the front wheels. In their defense, I expect they contribute significantly to the trike's stability. I suspect their absence is a marketing decision; tailed fairings would have a more extreme appearance.

Too bad they are not included. OEM could likely build them at nearly the same cost as the fenders we see. Will be a challenge for modders to build unless the modder has fiberglassing skills, I think.

[aerohead]

I would compare it to 'Sylph' which scored one of the lowest drag coefficients ever measured in Cal Tech's 'tunnel.

[racingdave]

Originally Posted by brucepick

The Elio fully enclosed reverse trike is currently slated for production and delivery in summer of 2014.

Thanks for posting this. I had not heard of them, but for $6,800 I would
buy one right now. I'll be very curious to see if they make it.
-dave

[drmiller100]

looks familiar..... (grins)

[KamperBob]

Looks great! I wouldn't worry about those front wheels. Remember, they need to turn. Fairings'd need to be supported. The additional weight and structural complexity seems like high fruit. I say they struck excellent balance. Kudos!

[freebeard]

There was a point where the aerodynamics went downhill (turned uphill?). They raised the cowl height, and consequently the frontal area, at least 10-20%. Compare the earlier rendering for the height of the headlight above the fendertop and note the semi-enclosed rear wheel.

You could totally duct tape coroplast onto those front fenders.

How about wedge-shaped pontoons that are flat on the inside in front and flat on the outside in back? That would pull air away from the body as it is widening, with some indeterminate effect abaft that.

And why aren't those ribs areas either side of the rear tire not all taillight? Like a big ribbed Mercedes one from the 90s?