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Old 02-28-2021, 02:16 PM   #31 (permalink)
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The Dymaxion had a Cd of 0.25. I think that the upturned nose on it is responsible for a lot of frontal lift and increased drag, given the slippery profile used as the basis for the design.

My next design is going to do away with the outboard wheels altogether for sure, now that I figured out how I might do the wheelwells. I plan to keep the same front track so that it can fit through bollards on a bike trail, but extend the wheelbase. I want to eventually be able to corner around 0.8-0.9G without tipping.

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Originally Posted by RustyLugNut View Post
Living in Southern California makes a vehicle such as these a year round practicality.
Mine is practical enough to use in the winter with 1-2" of snow on the ground, with VERY careful attention to the vehicle's dynamics while in operation. It did slide around a lot at 30 mph and I need to have a wheel repaired because some snow/ice may have damaged it. Although I DID have to walk to work when there was a foot of snow on the ground. The rear wheel had insufficient traction to plow it through the snow and the snow would get caught in the footwells.

I also ride it in the rain, albeit the front wheels like to splash water in my face. I'm planning to install a windshield and roof for it when I get the chance, and will be designing a wiper system.

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Old 02-28-2021, 03:57 PM   #32 (permalink)
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The Dymaxion had a Cd of 0.25. I think that the upturned nose on it is responsible for a lot of frontal lift and increased drag, given the slippery profile used as the basis for the design.
Who's tunnel?

I've always suspected the same, But if you look at the 3/4 front view you can see the 'air keel'. It's actually a [Luigi] Colani-esque move, massive front wheel spats feeding a central jet.

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I want to eventually be able to corner around 0.8-0.9G without tipping.
Lots of negative camber and a high roll center. .
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Old 03-03-2021, 12:13 PM   #33 (permalink)
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Originally Posted by freebeard View Post
Who's tunnel?
Good question. The sources where I read of that 0.25 figure didn't say.

Quote:
I've always suspected the same, But if you look at the 3/4 front view you can see the 'air keel'. It's actually a [Luigi] Colani-esque move, massive front wheel spats feeding a central jet.
But under what conditions will it actually work?

I think the foot holes on my velomobile are helping to prevent some of the expected frontal lift. Mine is surprisingly stable while careening at 60 mph down a hill!

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Lots of negative camber and a high roll center. .
That is part of the plan. 3 degrees negative camber should do it justice, which is what I have now. A higher roll center will require a custom design of chassis and suspension versus what I have now. I think a wheelbase extension of an extra foot or so would also greatly improve things, as well as a more reclined seat to reduce center of gravity AND frontal area. Maybe even 1G cornering or more is possible. If the traction limits of the tires are exceeded, then it will be almost tip-proof, which would be the ideal.

I think a frontal area of ~0.45 m^2 may be possible with the current 980mm(39") front track width while having the airflow going passed the sides of the body remain tangent with the front wheels. That design might necessitate a large front greenhouse area like the Go-One EVO-K velomobile or the Versatron Vector in order to see in front of my knes/feet while pedaling, which would not be pleasant in the summer, but there are mitigation strategies to help with that such as a tinted polycarbonate to filter UV light, NACA ducts, and a PLC-controlled thermos filled with ice water. It would really take some building and experimentation to see what is needed, as it may be possible to still make such a reclined setup allow my field of vision towards the road visible over the kneebumps.
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Old 04-05-2021, 03:41 PM   #34 (permalink)
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The new(used) batteries arrived. I was tired of having only a 50 mile range and ordered two used Greenway 46.8V 15.6AH packs. I've recently obtained a new job as an electrical engineer and have been using this vehicle to visit job sites, getting reimbursed $0.575/mile, and needed a plug and play range increase that didn't require me to take the trike out of commission and re-do some of the electronics to accomodate the 72V pack I've been working on. So the plan for the near future is to run two 46.8V packs in parallel and increase peak power to 3 kW, improving range and acceleration, but not top speed. A printout of their delivered capacity during testing from the seller was provided. They were 15.51 AH and 15.35 AH respectively. This means 30AH when I parallel the two together is a given. I charged both of them up to full.

I hadn't had much in the way of free time so I didn't get to fully install them. I need to make a wiring harness to parallel them together AND I need to make a custom enclosure to fit both of them lengthwise underneath the boom with their narrowmost dimension placed between the rotating pedals. Being a holiday weekend, all the places I could get the needed parts were closed, so I decided to devote the free time I had after 3pm yesterday to testing the vehicle.

I was able to fit ONE of the battery packs underneath the boom. I used the higher capacity pack of the two for a total capacity of about 726 watt hours. It was held to the boom with zip ties, a temporary solution but one that works. To say I was pleased with the results would be to understate things. I rode it 83.6 miles, with cruising speeds of 30-35 mph plus pedal input. At the end of the ride, I had used 15.5 AH, and had consumed slightly under 8.7 wh/mi, the equivalent energy consumption of almost 4,000 miles per gallon! The battery wasn't yet dead, but it was on the verge of being empty. I plugged in my charger for about 20-30 minutes at an outlet at a pavilion in a park, got a few AH back, and then rode it another 20 miles.

I now have a decent range EV! As an aside, all of the comments I got from random ghetto dwellers while riding it around East St. Louis were hilarious. This thing certainly attracts attention.

Once I put both packs in, a 150+ mile range @ 30-35 mph is assured, and there is a possibly of a 100 mile range @ 45 mph. Plus it's still very pedalable with a dead battery. When operating purely under pedal power with the motor off I can leave lycra fetishists on roadbikes behind in most settings. I won't have any range anxiety using it to visit job sites anymore and won't have to charge it every day, and can opt to just change when it is convenient instead.

An actual car with accelerator and brake pedal instead of bicycle pedals with this sort of form factor and efficiency that is usable on the road in traffic is very doable. In mass production, such a thing weighing in at under 150 lbs, with seating for one, an integrated roll cage, micro AC unit for climate control, enough trunk space for 2 weeks worth of groceries, weather protection, all wheel drive via inexpensive e-bike hub motors and controllers, better aerodynamics on par with a Milan SL velomobile, a 3 kWh pack for a capability of 100+ miles range @ 70 mph, 0-60 mph in under 4 seconds with a 100 mph top speed, enough solar panels for it to cruise indefinitely @ 35 mph in direct sunlight without draining the battery OR recoup about 30 highway miles range a day sitting in a parking lot for 8 hours, could be built for much LESS THAN $10,000. I could buy all the parts off the shelf for such a thing except for the chassis/body(which would have to be designed and made) for under $3,000. The battery pack required for these specs would be so small that any 110V outlet is the equivalent of a CHAdeMO charger for a normal full sized electric car and any run of the mill 220V 50A outlet can function as a 15-minute fast charger, and if you destroy the pack doing something stupid, you'd only be out a few hundred dollars instead of tens of thousands of dollars. Operating costs would be expressed as a fraction of a cent per mile.

It's a travesty that no one is thinking outside the box and making an actual car like this for sale to the general public.
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Old 04-05-2021, 04:05 PM   #35 (permalink)
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could be built for much LESS THAN $10,000
Arcimoto/Tilting Motors (150lb, $2K). All that's missing is the human-hybrid part.
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Old 04-05-2021, 06:24 PM   #36 (permalink)
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Arcimoto/Tilting Motors (150lb, $2K). All that's missing is the human-hybrid part.
Do you have a link? On the Arcimoto website they list their vehicle as being 1,300 lbs. It also doesn't have the aerodynamics needed.
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Old 04-05-2021, 09:01 PM   #37 (permalink)
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That would be the FUV family.

Platform 2 This chart shows 3kWh, 35 Wh/mi and 8sq ft footprint.
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Old 04-06-2021, 03:38 AM   #38 (permalink)
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150lbs? That's scooter/moped weight class. And on the light side even there.

I suppose an enclosed 3-wheel electric bike/velo could easily be in that range.
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Old 04-06-2021, 12:20 PM   #39 (permalink)
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I wonder is that 8sq ft footprint a rectangle or a T-shape?

On the light side isn't surprising, since they have associated with Sandy Munro and XponentialWorks.
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Old 04-07-2021, 09:42 AM   #40 (permalink)
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In avaition the 8 sqft is a flat rectangle piece of plywood equivalent. A T shape would have more drag because it would be physically bigger with more edge.

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