# Chassis idea for an E.V.



## mizlplix (May 1, 2011)

I have always had a fascination with the old original STP turbine car that P.J. drove at Indy. It had a then radical chassis design.

It was shaped like a capitol letter "I".

The front suspension and rear suspension was connected by a "backbone design frame. The drivers pod was on the inboard side and the giant turbine was outboard.

This allowed the driver and the powerplant to sit low in the chassis.

The backbone section was triangular in cross section, wider at the bottom than top.

It seems to me that an E.V. could be built utilizing this design also. The front suspension could be a self-contained unit like maybe Fiero, or the like. The rear could be a solid mount diff with independent suspensions outboard, or maybe even a reverse trike....

This would allow for the motor-transmission-batteries to all be mounted centerline of the chassis, as well as low.

The driver and passenger seating would be outboard and really low.

I need to do some shopping for an aftermarket body that would look good and fit this scheme. 

Any comments? Am I overlooking anything?

Miz


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## piotrsko (Dec 9, 2007)

chassis uses same theory as a bug pan with a truss welded along the top? 

other than passengers having to be a bit stand-offish and requiring their own door, would work well except for a t-bone accident.


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## frodus (Apr 12, 2008)

look into formula vee cars (or formula V). They use bug parts and had open wheels like that. Lots of older designs have the STP look to them.


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## Woodsmith (Jun 5, 2008)

The Sub 3wheeler is another design that has the driver and ICE side by side, but low in a space frame chassis.

Your plan could work easily with a VW bug or 911 trans with the motor at the back.

Alternatively, for a 4x4 version a Styer Puch Halfinger chassis would make a good conversion.

















Backbone tube, diff at each end, 4F1Rx2 trans at the rear, motor to replace the 600cc ICE. The swing arm suspension could be converted to longer wishbones.


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## mizlplix (May 1, 2011)

Thx, Wood: That is really cool. Sometimes I forget that vehicles are built in the rest of the world too (LOL).

I dont know how it is else where, but here in USA corporations, they use the generational approach to designing.

That means that if I were a young engineer with GM (Ford-Chrysler-ETC) and they gave me a project to design a medium class rear axle assembly, that assembly would be used until I retired or died. Then the window would be open for another engineer to design a newer medium class rear axle assy.

My axle would be the standard medium axle for GM. None would be allowed to be designed. So, we live with either a good, flawed or barely decent axle assy because I am still alive and it would be an insult to me to have another designed for any reason.

The Japanese Automotive Engineers do not have that restriction. They start with a clean sheet with each project. They even borrow from each other. Example: If you look at grey inside door handles on many Japanese cars, you will see they are the same unit. Because it was a good design and not worth de-doing just to do it.

We also do not benefit from user feedback. "The people will buy what ever we build, we are GM and that is enough."

Wrong. On many levels, yet they still persist in their empirical view of the American auto buying public.

To pimp the Volt as an electric car during design, then spring a Hybrid on us is the latest example of their egos.

Many times I wish I had access to the World's supply of vehicles for pieces to build from. I envy you.

Rant off-Miz


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## mizlplix (May 1, 2011)

OK, 

The safest EV design would protect the cells and occupants.

The weight needs to be near the center of the polar moment of rotation and low in the chassis.

To be comfortable to drive and feel natural, the car's rotational axis needs to be through the driver's location. 

Light weight (obviously).

All this can be achieved in a reverse trike design.

The "backbone" frame lends its self to this ideally also. The motor needs to be inside the frame along the centerline, the cells lined up from the front of the motor to the front bumper and can be withdrawn out the front through an access door for any servicing that may be required.

I guess for now, we are stuck with a motorcycle derived drive tire and suspension, (Driveshaft type) then belt driven back over to the cars centerline where the motor resides. It can provide the needed reduction ratio to allow a single speed drive.

AC or DC...The argument still rages. Although AC has the RPM deal going for it while the DC has the torque deal on it's side.

As for the side impact issue....A backbone design allows you room to custom design a "pod" around the driver/passenger, that will fit inside the chosen body as well as can be done for any sort of vehicle.

The real issue is "crush space" or lack of, which a host of vehicles share.

Miz


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## piotrsko (Dec 9, 2007)

OK, new question: where are you headed here? I'm confused (not all that hard any more)


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## Duncan (Dec 8, 2008)

Hi Mizlplix

The old Loti (Lotuses?) used a backbone chassis,

I am not convinced 
IMHO having the chassis rails outboard gives more stiffness and some protection from side impact


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## mizlplix (May 1, 2011)

Hi Piot: I am in the dreaming stages of my new EV project. (There is life after EV)

Looking for ideas/variations on my theme-" A Back-Bone style chassis".


Duncan: Yes, this is what I wanted. Ideas/pics of other chassis used by "the big boys" in order for me to simplify and hopefully eliminate mistakes in my final design.


Goal: A fabricated, back bone chassis that will accept a Donor suspension from a late model, easy to obtain car, designed for E.V. use.

Criteria:

Power-train/cells/heavy items concentrated along the central structure-for safety, handling and utilization of a usually dead space.

The fewest attachment points for the front and rear suspensions.

Achievable by the average back-yard mechanic. 

Short overall project time, start to finish.

Good performance.

Able to mount several different body styles according to the builders tastes.


Miz


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