Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - CarBEN Model -- 1/24th scale model and 3D computer model for EV

NeilBlanchard · 09-30-2010, 01:07 AM

Hi Dave,

Thanks for the questions. The tires are intended to be 15" 185's, though in the end, I hope to make my own rigid wheels with solid (non-inflating) tires. So they are close enough to stand in for now.

Yes, the rear track is narrower -- like the EV1 and Dave Cloud's Dolphin. This is the only way to drop the Cd below 0.2, I think? From what I understand, a tadpole trike would handle really nimbly, so the answer may well lie in getting the correct suspension geometry. I'm assuming at this point that the front suspension will be double wishbone (to avoid the height of a strut) and the rear would be independent trailing arms, without a beam axle. I've seen these set up with multiple linkage so that they are anti-squat and you can actually get passive "steering" out of the back suspension. But, I have not gotten into the details, yet. The aerodynamics are at the top of my priorities, and I have to figure out how to best build it!

I thought I put in a bit on the asymmetrical seating -- I've answered a similar question on Facebook earlier today. Basically, the most the weight would be unbalanced is about 300-350 pounds (the two "extra" seats are for shorter adult/kids), and that weight is on the higher part of the road crown; and away from the much rougher right side edge. I've only ever had to replace wheel bearings and the like on the right side of any of my cars. The battery pack in the floor is 800-900 pounds, and since most cars have the driver on the left -- and most often the driver is the only person in the car; so, most of the time the CarBEN will be in total balance! On the other hand, most cars are usually out of balance by up to 250 pounds (or more).

There is a company right nearby in Cambridge, MA called Levant Power, that was started by folks from MIT, and they make regen shocks that have micro turbines and little electrical generators in each shock -- and not only do they generate power, they are tunable. If they had ride height/leveling that would be very helpful for an aerodynamic car like CarBEN.

Okay, I now have all five 3D figures in the model, and the two passenger seats right behind the driver are splayed slightly to fit their legs in, while still having decent headroom. You can see this best in the plan section:

Longitudinal section views:

Do you want a copy of the SketchUp file? I may try to bring it into Banzai 3D (FormZ in new interface) and see if I can get a solid model.

09-30-2010, 01:07 AM	#174 (permalink)
NeilBlanchard Master EcoModder Join Date: May 2008 Location: Maynard, MA Eaarth Posts: 7,908 Mica Blue - '05 Scion xA RS 2.0 Team Toyota 90 day: 42.48 mpg (US) Forest - '15 Nissan Leaf S Team Nissan 90 day: 156.46 mpg (US) Number 7 - '15 VW e-Golf SEL TEAM VW AUDI Group 90 day: 155.81 mpg (US) Thanks: 3,475 Thanked 2,952 Times in 1,845 Posts	Hi Dave, Thanks for the questions. The tires are intended to be 15" 185's, though in the end, I hope to make my own rigid wheels with solid (non-inflating) tires. So they are close enough to stand in for now. Yes, the rear track is narrower -- like the EV1 and Dave Cloud's Dolphin. This is the only way to drop the Cd below 0.2, I think? From what I understand, a tadpole trike would handle really nimbly, so the answer may well lie in getting the correct suspension geometry. I'm assuming at this point that the front suspension will be double wishbone (to avoid the height of a strut) and the rear would be independent trailing arms, without a beam axle. I've seen these set up with multiple linkage so that they are anti-squat and you can actually get passive "steering" out of the back suspension. But, I have not gotten into the details, yet. The aerodynamics are at the top of my priorities, and I have to figure out how to best build it! I thought I put in a bit on the asymmetrical seating -- I've answered a similar question on Facebook earlier today. Basically, the most the weight would be unbalanced is about 300-350 pounds (the two "extra" seats are for shorter adult/kids), and that weight is on the higher part of the road crown; and away from the much rougher right side edge. I've only ever had to replace wheel bearings and the like on the right side of any of my cars. The battery pack in the floor is 800-900 pounds, and since most cars have the driver on the left -- and most often the driver is the only person in the car; so, most of the time the CarBEN will be in total balance! On the other hand, most cars are usually out of balance by up to 250 pounds (or more). There is a company right nearby in Cambridge, MA called Levant Power, that was started by folks from MIT, and they make regen shocks that have micro turbines and little electrical generators in each shock -- and not only do they generate power, they are tunable. If they had ride height/leveling that would be very helpful for an aerodynamic car like CarBEN. Okay, I now have all five 3D figures in the model, and the two passenger seats right behind the driver are splayed slightly to fit their legs in, while still having decent headroom. You can see this best in the plan section: Longitudinal section views: Do you want a copy of the SketchUp file? I may try to bring it into Banzai 3D (FormZ in new interface) and see if I can get a solid model. __________________ Sincerely, Neil http://neilblanchard.blogspot.com/