[Duncan]

Hi Darxus
I used to ride a recumbent HPV (Human powerred vehicle) but it was a two wheeler the few times I borrowed a trike it was great fun but very physical
With a couple of inches ground clearance (the chain goes under your bum) you have to lean your body into the corners and you are so low that other road users can't see you

A leaning machine is better and becomes more stable the higher it is
Saying that I can relate to the wheel going away from under you and the bum hitting the road - better than the head!

A leaning three wheeler should avoid that the failure would be a skid

The racing HPV's are normally very low but going higher and having just the wheels below the beast will not have a big drag penalty

Wheel spats
If you are serious about low drag you need to look at the solar racers
If you have a shape that the flow doesn't separate from (stream-lined) then the old CD x area no longer applies
At this stage it is the "wetted area"
So it is better to go wider and build everything into your aero-body

Getting a decent body is not that difficult - the devil is in the details around the holes for the wheels and canopy

How long were you allowing for your commute?
The HPV record is now over 50mph - normal bikes its about 35mph

It would not take much power assist to get a semie-streamlined HPV to cruise at 35+mph
(Two wheeler HPV with nose and tail fairing)
A fit guy (not me) could do it by pedal power

Angle of Recline
Much better than the face down method the motorbikes use
You will need a head rest - or neck muscles like a bull

You really have three ways to go here

light weight (50lbs) low power 50 - 150 watts
pedal + electric
or
200+ lbs, 400+ watts light weight electric+
or
Mini Car
1000+ lbs, 30+Kw

[Darxus]

Originally Posted by toddshotrods

The problem is you have to look forward at the road, meaning your neck would be bent forward.

Ah, thanks. Laying flat in bed with just my head propped up while using a laptop for hours makes my throat sore from the angle. I think sitting up this much wouldn't be a problem. Definitely worth considering, and testing.

[Darxus]

Less than twenty-four hours for a response from the NH DMV:

If your looking for certain specifications there are two websites you can refer to. They are
http://www.gencourt.state.nh.us/rule...saf-c3200.html and
http://www.gencourt.state.nh.us/rsa/...es/default/asp

At the second website you will be looking for RSA 266:1. That will take you through all of the inspection requirements as well as the first website being our rules for inspections. If you have any further questions you may refer to State Police at 603-223-8778.

If you need further assistance please do not hesitate to ask.

Thank you,
Brandy Stone
Division of Motor Vehicle
Inspection/Dealer Desk

Direct link to RSA 266:1: http://www.gencourt.state.nh.us/rsa/.../266/266-1.htm

[fishguts]

Originally Posted by Darxus

Ah, thanks. Laying flat in bed with just my head propped up while using a laptop for hours makes my throat sore from the angle. I think sitting up this much wouldn't be a problem. Definitely worth considering, and testing.

You'll just have to experiment to see what's comfortable for you. As illustrated, you'll be just looking over your knees - that's pretty laid back for sure. Would be a neat low profile, but an old bugger like me is wondering how the heck you'd get out of that thing! ha ha Person in the back seat better be real skinny!

But I do like it - sleek, cool looking.

The plexi windshield will hold up fine (unless you race on a dirt track). Plexi usually gets scratched when people clean it with paper towels. A soft cloth is what to use. Most of my experience with it is with boats, so that's a different world, but look at all the motorcycles out there with plexi fairings and windshields. It's also easy to form. I can tell you how sometime if you are interested.

[toddshotrods]

Originally Posted by Darxus

Ah, thanks. Laying flat in bed with just my head propped up while using a laptop for hours makes my throat sore from the angle. I think sitting up this much wouldn't be a problem. Definitely worth considering, and testing.

Put a long rod through the driver's head indicating his line of sight. Right now he's looking at the stars - nice view but I'd be beating him in his bubble head if I was her, telling him to watch the road! Now rotate the head and rod, from the shoulder/chin area, until the line of sight touches the surface at a point about the length of the entire vehicle in front of it. That will give you an indication of how much you'll have to crank your dome forward to see where you're going. You;ll also see how much you're stretching your neck to see forward.

If you try doing a real-life mock-up you have to be reasonably accurate with the measurements. Get some boards from the local hardware/home improvement store and duplicate what's in the model as closely as possible. You'll want something solid like wood, so it won't give and allow you to subconsciously shift it into a more comfortable position. Put something small (like a pop can) on the floor a vehicle length in front of the nose of your vehicle and see how long you can stare at it before fatigue sets in. What you want to be conscious of is mental fatigue, more than if you think you're comfortable. If you're uncomfortable, you'll stop and get out. Not very much fun though, if it happens every fifteen minutes. On the other hand, if you begin to experience serious mental fatigue, you start endangering yourself and others on the road.

I have neck issues. If I sat in that car for five minutes I would have a migraine, but I have been on motorcycles with low clip-on bars for hours with no problems. It's all relative...

[Darxus]

Join me on IRC (Internet Relay Chat) in ##ecars on irc.freenode.net (no typo, two #'s).
If you're not familiar, this protocol is older than the web, and used by lots of people. Instructions are here: http://freenode.net/using_the_network.shtml
It works best if you can stay connected 24/7.


I just noticed that the world record for an electric vehicle is 555.6 km (345 miles) in a Daihatsu Mira Van with no apparent interest in aerodynamics. Anybody want to sponsor me on a battery pack? Seriously. I'd get moving much quicker.


Looks like I'll be building a mock-up out of 4'x8'x7/16" chip board for $15 each, the cheapest stuff I found that seemed sturdy enough. Should I go with the cheap option of only getting one, cut down the middle lengthwise, and holding it together with scraps in the barn that my house came with, or at least $80 (including truck rental) to start a more extensive mock-up?

I'm thinking the one board will give me all I need, since I have a detailed and easily manipulated computer model, and I just need to make sure the space is tolerably large enough for humans.


Looked through New Hampshire law, and what looked applicable of federal law. No major problems, for which I am very thankful. No problems from the state. The two annoyances are, of course, from the DOT.

All glass (and acrylic / plexy / etc., collectively called "glazing") is expensive due to extensive safety laws, specified in an ANSI document that I have to PAY ($60) to be able to read: ANSI/SAE Z26.1-1996. Flat glass is expensive. I expect curved glass to be silly expensive. This seems to me to be a significant barrier to development. I really don't see what laws need to apply to an acrylic windshield, other than "Visibility must be at least Z." And possibly "Won't break if you drop an N pound rigid object on a section X"xY"".

Looks like being classified as a motorcycle is going to mean putting controls in the standard motorcycle places: Front brake and throttle on the right handlebar, rear brake at the right foot. I'd prefer right foot throttle and left foot brake. But I think I can deal with that one.

But other than that, no significant change of plans.


toddshotrods:
Yup, this is why I need to build a mockup. Humans are complicated. Thanks for the point on mental fatigue. I love the feeling of riding a motorcycle in a crouched position, and I've thought about using that, but I really can't see how I could remain comfortable without any support from the wind. My SV650 has race handlebars and foot pegs. Makes the interaction with the road much more intimate.
http://www.chaosreigns.com/gallery/D..._pegs.jpg.html

[toddshotrods]

Originally Posted by Darxus

...Looks like I'll be building a mock-up out of 4'x8'x7/16" chip board for $15 each, the cheapest stuff I found that seemed sturdy enough. Should I go with the cheap option of only getting one, cut down the middle lengthwise, and holding it together with scraps in the barn that my house came with, or at least $80 (including truck rental) to start a more extensive mock-up?

I'm thinking the one board will give me all I need, since I have a detailed and easily manipulated computer model, and I just need to make sure the space is tolerably large enough for humans...

That one sheet should give you enough, combined with the scraps you have, to mock up a stable seating arrangement. I would use smaller pieces that can be easily attached and relocated for other critical elements. Foam and poster board with masking tape are good too. I like using them because they're cheap. You can build mock-up motors, batteries, etc, really cheap and try different sizes, locations, configurations.

Another thing you should do is solidly box in your foot space. See how it feels when your feet absolutely cannot move outside the confinement. Likewise a couple pieces screwed on to keep your elbows and hips confined. Allow for any padding, and maybe glue some cheap upholstery foam on it to get a real sense of things.

This may sound crazy to people who are conversion oriented, but it's a crude form of how the vehicles you're converting were developed. We tend to take for granted the engineering that goes into developing personal transportation.

Originally Posted by Darxus

...All glass (and acrylic / plexy / etc., collectively called "glazing") is expensive due to extensive safety laws, specified in an ANSI document that I have to PAY ($60) to be able to read: ANSI/SAE Z26.1-1996. Flat glass is expensive. I expect curved glass to be silly expensive. This seems to me to be a significant barrier to development. I really don't see what laws need to apply to an acrylic windshield, other than "Visibility must be at least Z." And possibly "Won't break if you drop an N pound rigid object on a section X"xY""...

They might be annoying, but they prevent some really bad things from happening. The biggest issue is how the material breaks. Tempered saftey glass shatters into thousands of little benign glass chips. They can cut but not stab and slice. Windshields are made of regular glass with a plastic film in between that keeps the glass from dislodging and becoming a weapon (other than being a nice place for your head to stop its forward momentum). Tempered glass would be horrible on the windshield because all those chips can aim straight for your eyes, open mouth, etc.

Plastic also breaks in different ways. Plexiglass, which was once common, breaks like normal glass into shards that can puncture and slice mercilessly. Lexan doesn't, and is the standard material used for racing applicatios. It really does make a huge difference what you use.

You also have to dig deep enough to see which if those requirements relate to a specialty car in your state. In Ohio, we have a LOT of freedom. They mainly check basic safety equipment. We have to have receipts for every piece that is used to build it though.


Have fun!

[John]

Originally Posted by toddshotrods

If you try doing a real-life mock-up you have to be reasonably accurate with the measurements. Get some boards from the local hardware/home improvement store and duplicate what's in the model as closely as possible. You'll want something solid like wood, so it won't give and allow you to subconsciously shift it into a more comfortable position. Put something small (like a pop can) on the floor a vehicle length in front of the nose of your vehicle and see how long you can stare at it before fatigue sets in. What you want to be conscious of is mental fatigue, more than if you think you're comfortable. If you're uncomfortable, you'll stop and get out. Not very much fun though, if it happens every fifteen minutes. On the other hand, if you begin to experience serious mental fatigue, you start endangering yourself and others on the road.

Looking at your preliminary design I think your passenger will be very uncomfortable sitting in such a confined position and not being able to see past the drivers head. What happens to the driver’s control of the vehicle if the passenger lifts their knees or moves their arms as they would tend to do a lot if they are uncomfortable? The laid back position of the driver also means that their elbow joint is almost straight. What does this do for their range of movement and the forces they can comfortably generate at their hand to move the steering. How much could the handle bars move forwards while steering the machine before that hand had to let go due to range of movement issues. Can you afford to let go with hand controls?

I would consider using a 60% laminar low drag body. The higher the percentage laminar the more the thickest section of the body moves aft. This will help with packaging and aero at the same time. Rather than using a pure body of rotation consider stretching the top half vertically for better packaging.

For aerodynamic stability consider increasing the side area aft of the centre of gravity. Objects in motion through the air the centre of pressure will try to follow the centre of gravity. As for considering the angle of attack irrelevant consider what happens when the car encounters a cross wind or turns a corner. A 10MPH cross wind at 35MPH would cause about a 16 degree off axis wind direction besides the pointy front end could be dangerous to pedestrians. I believe the EV1 was designed to be most aerodynamic at 10 degrees off axis wind direction.

The attached sketch is something I drew a couple of years ago. You may find it interesting.

[Woodsmith]

Have a look at Project Sanderson's Flickr. You will see in the set how he went about designing the body for his HPV. It might be useful for you.

He mocked up like this.




So that he could build a body like this.

[John]

It's interesting just how shrink wrapped some of those HPV's get. Some have taken to using a camera and video screen to navigate and gone
windowless in pursuit of the ultimate slippery shape. My concept is a behemoth in comparison. One of those HPV's hit 80 MPH on just human power (1/4hp?).

The thing that really derailed the idea for me was the glass windows that would be required to get it legal in NZ. Another difficulty is windscreen wipers are mandatory and must wipe at least 70% of the screen in NZ. I'm sure glass could be made for a price. Getting it optically clear and distortion free through that tight and changing bend at the front and with its compound curvature it would be exceedingly difficult and hence prohibitively expensive. Coming up with a system to effectively wipe that screen and not disrupt the air flow (such as parking inside the A pillar) would certainly be challenging. The concept was also just a bit too in your face for me.

Note the 60% laminar profiles that wrap the wheels and people pod and how they allow the wheel pants and pod to be fairly short at the rear without resorting to a kammback. Note how the rear passenger can look over the driver and both can lean forward to some degree. This should help make the design less claustrophobic. I wanted the design to be reasonably large in profile at least so that it had some presence on the road and other vehicles would see it.