Aero trunk lid project

[brucepick]

Chaz, do you have more pics of this from different angles? Did it stay on the car and how did it affect the mpg?

I looked in the car's gas log but didn't see any notes re. when the device was added or removed.

Originally Posted by ChazInMT

Sorry to be so late in the game here. Seemed to me like the thing to build would be something like this if you have a notch back.



Unless you wanna go drag racing, but that's hell on fuel mileage, unless you pulse & glide....which is hell on your win loss record.

[ChazInMT]

Oh, Sorry, I meant to respond the other night, this is a photo shop add on, meant to make one using the T-Vargo (Kitteh) method of construction styrene foam but never did. I reasoned that the air is definitely not attached starting at the top of my back glass, I can tell when it rains, there is no air flow on it. I figured to make this and follow the lines on my trunk on the sides, and it would resemble the shape of the new Honda CR-Z, a little. I figured it would net me 5-7% MPG boost. I was going to make it so I could get it on & off relatively easily and only use it on my cross county highway trips which I make 3-4 times a year. It is just under the template curve by like 2".

[California98Civic]

Originally Posted by ChazInMT

Oh, Sorry, I meant to respond the other night, this is a photo shop add on, meant to make one using the T-Vargo (Kitteh) method of construction styrene foam but never did. I reasoned that the air is definitely not attached starting at the top of my back glass, I can tell when it rains, there is no air flow on it. I figured to make this and follow the lines on my trunk on the sides, and it would resemble the shape of the new Honda CR-Z, a little. I figured it would net me 5-7% MPG boost. I was going to make it so I could get it on & off relatively easily and only use it on my cross county highway trips which I make 3-4 times a year. It is just under the template curve by like 2".

So you were going to freehand cut the EPS foam with a hot wire? Or do you have other equipment? Were you planning any visibility out you back window? This is a cool idea. I like the specific application, removable.

[t vago]

Originally Posted by California98Civic

So you were going to freehand cut the EPS foam with a hot wire? Or do you have other equipment? Were you planning any visibility out you back window? This is a cool idea. I like the specific application, removable.

I used a jigsaw and a steakknife. Much more reliable than hot wires for large projects.

[ChazInMT]

Actually I was planning on making a framework out of 2x2 redwood and screwing the foam to it. I figured to put a plexiglas window in the 5" flat back of my addition. I was gonna use 2" thick foam and shape it with whatever worked, 60 grit random orbital sander or power hand planer, to radius the top of the sides/sides of the top.....hope that makes sense. It's funny, the part itself would not really be that big. I've toyed with the idea of making them out of inflatable material...how cool would that be? You inflate the part and strap it onto the trunk lid to fill the gap. Even a 5% gain in FE would take me from 37mpg to 39 mpg.

[CFECO]

I may have missed something along the way? Why do F-1,Top Fuel and Indy cars have small pointy noses which taper up to the cockpit "section" diameter, rather than the "Template" shape? Anyway, here is an interesting "car" I found along the way, and the back of a Pontiac Aztek doesn't look so bad after all!

[t vago]

Originally Posted by ChazInMT

Actually I was planning on making a framework out of 2x2 redwood and screwing the foam to it. I figured to put a plexiglas window in the 5" flat back of my addition. I was gonna use 2" thick foam and shape it with whatever worked, 60 grit random orbital sander or power hand planer, to radius the top of the sides/sides of the top.....hope that makes sense. It's funny, the part itself would not really be that big. I've toyed with the idea of making them out of inflatable material...how cool would that be? You inflate the part and strap it onto the trunk lid to fill the gap. Even a 5% gain in FE would take me from 37mpg to 39 mpg.

Sounds really good, except that you don't want to use screws to attach the foam to the framework. (Well, unless you can find screws with ridiculously large helical ridges).

An inflatable aeromod... I was thinking to do the same with my aerocap. It'd be pretty neat to flip a switch, cause an air pump to turn on, and watch an aerocap appear as if from nowhere.

[ChazInMT]

Yeah Baby, I like it, Just PUSH the Button and it gets all big and hard "Secret Agent" style! Positively Shaggadelic!

[aerohead]

Originally Posted by CFECO

I may have missed something along the way? Why do F-1,Top Fuel and Indy cars have small pointy noses which taper up to the cockpit "section" diameter, rather than the "Template" shape? Anyway, here is an interesting "car" I found along the way, and the back of a Pontiac Aztek doesn't look so bad after all!

*Indycar and F1 cars momentarily approach the transonic region where supersonic shockwaves can appear over minor portions of high-acceleration regions.
* Super-sonic drag is ruled by shockwaves and a 'pointy' nose helps mitigate this.
* The 'pointy' nose also has less cross-section which means more air to the front splitter (wing),which can win or loose the Indy 500,as just happened to Danika Patrick.
* All this allows maximum use of whatever the rulebook allows each season,whether wings,splays,strakes,chines,deflectors,ground-effects tunnels,slats,flaps,fins,or what have you.
-------------------------------------------------------------------------
* Indycar/F1,wind tunnel tested in the 1980s demonstrated the following:
* Basic body = Cd 0.25
* Body with tires = Cd 0.54
* Body with tires and wings = Cd 0.97-1.17
Not much help to aero-modders!
--------------------------------------------------------------------------
*Top-Fuel dragsters ARE operating in the transonic regime,their 'pointy' noses,like the F1/Indycar are also doing double-duty,managing shockwaves,and allowing the maximum volume of air to the front wing,to prevent blow-over,potentially lethal at those velocities.
* The point also allows perfect triangulation of the tube chassis,with minimum mass,high rigidity,strength,improved power-to-weight ratio.
* The 'wedge' guarantees attached,ram-flow to the engines bug-catcher.
* Once the air goes beyond the engine it is basically full separation.Dragsters have the highest drag of all race cars,often exceeding the Cd of a parachute,except for Jocko,and the Arivett Brother's streamlined dragster.
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* As to the Pontiac Aztek,do you have some specific data or information about its aft-body that you'd like to share? Frank Lee's been looking at this one.I know he and the rest of us would appreciate it.Thanks

[ChazInMT]

My 9 year old son saw an Aztek one day and asked "What is that Dad?" I told him it's an Aztek....He said "Really?? ...That's a good name for it, AssTech...Get it??"

I think of him saying that every time I see one.