2/7/2010 - Three Seat Concept Design

[AR-51]

External bumper.

http://www.youtube.com/watch?v=JWa74YyleVI&feature=pyv&ad=4112916588&kw=b umper&gclid=CLPlroer-58CFRKiagod71oylg

http://www.youtube.com/watch?v=57P6hqo57C4

http://www.dieselpowermag.com/news/0...car/index.html

I was trying to find crash test information on police car push bumpers, but was unable to too.

Push/pursuit bumper

Its most prominent feature is a unique push/pursuit beam that extends beyond the normal bumper of a police car. The high-strength stainless steel and cast aluminum push bar is used for assisting stranded vehicles, but it can also be used as an offensive tool during a car chase. With a properly executed push in the corner of the fleeing vehicle, the push beam will force the suspect’s vehicle into a spin. This technique is used to disable fleeing vehicles, thus avoiding a high-speed chase and possible injury to innocent bystanders.

The separate push beam has another benefit: it reduces the need for costly body repairs. Like the push/pursuit beam on the front end, the rear bumper also has a structural polymer extension.

http://www.canadiandriver.com/2002/0...police-car.htm

[AR-51]

Additional back window design.

The design is intended to protect the back seat passenger from the sun and at the same time allow the driver to use the rear view mirror.

[AR-51]

Updated Three Seat Concept:

[Grendal]

It looks like your door will hit your wheel pod. Cool design though.

[AR-51]

Originally Posted by Grendal

It looks like your door will hit your wheel pod. Cool design though.

Thanks, I will have to fix it.

Update:

[NeilBlanchard]

Hi,

The departure angle on the top in the back seems to be a little too steep? It looks like it is a little less than 25 degrees, which is higher than the Hucho book recommends -- I think that 18 degrees is about as steep as can be done at highway speeds.

You are getting very fine results in SketchUp -- I attempted to model my CarBEN design, and failed badly; with lots of polygons dropping out. Have you seen the work that a young fellow named Ray Ochoa is doing in SketchUp?

http://www.ray-ochoa.com/

I'm hoping that he can help me by modeling the CarBEN design.

[AR-51]

Originally Posted by NeilBlanchard

Hi,

The departure angle on the top in the back seems to be a little too steep? It looks like it is a little less than 25 degrees, which is higher than the Hucho book recommends -- I think that 18 degrees is about as steep as can be done at highway speeds.

You are getting very fine results in SketchUp -- I attempted to model my CarBEN design, and failed badly; with lots of polygons dropping out. Have you seen the work that a young fellow named Ray Ochoa is doing in SketchUp?

http://www.ray-ochoa.com/

I'm hoping that he can help me by modeling the CarBEN design.

I just measured the departure angle, it looks like its about 20 degrees at the lower half. I also measured Aptera's departure angle, and it looks likes it's about 18 degrees like you said.

I would need to make some changes. Thanks for the information and the link.

[NeilBlanchard]

Another comment about the wheel fairings: both the production PPX and the Edison2 Very Light Car have asymmetrical sides -- the inside is flatter in both cases. I think this is because they are interacting with the air flow around the main part of the chassis, and if too much air is being deflected in between, then the pressure goes up, which makes it higher drag.

[KarenRei]

Originally Posted by AR-51

I just measured the departure angle, it looks like its about 20 degrees at the lower half. I also measured Aptera's departure angle, and it looks likes it's about 18 degrees like you said.

I would need to make some changes. Thanks for the information and the link.

The important thing is that it's not so much the act of tapering to a point or line that reduces drag. It's keeping a proper taper angle as long as possible. It's far better to truncate than to use too steep of an angle.

Also, I'm pretty sure you're going to have issues with upforce/downforce with your current design, although I think I mentioned that before.

[AR-51]

Originally Posted by NeilBlanchard

Another comment about the wheel fairings: both the production PPX and the Edison2 Very Light Car have asymmetrical sides -- the inside is flatter in both cases. I think this is because they are interacting with the air flow around the main part of the chassis, and if too much air is being deflected in between, then the pressure goes up, which makes it higher drag.

Thanks again for the information. I will have to redesign the wheel fairings to incorporate the asymmetric design and to increase the space available for the door.

Originally Posted by KarenRei

The important thing is that it's not so much the act of tapering to a point or line that reduces drag. It's keeping a proper taper angle as long as possible. It's far better to truncate than to use too steep of an angle.

Also, I'm pretty sure you're going to have issues with upforce/downforce with your current design, although I think I mentioned that before.

I Google search Hucho book (I got his name from Neil Blanchard post) and I fond a picture that gives an example of what the ideal shape should be.
http://ecomodder.com/forum/showthrea...il-8927-2.html

Could you be more specific about the upforce/downforce issues with the design?