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Old 01-10-2012, 11:10 AM   #21 (permalink)
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When alone, weather permitting I ride one of my bikes, probably like you Brian. The decision to build it side by side was based on the template for optimal aerodynamics as well as a Wife who wants to ride shotgun.
Another consideration is the center of mass being positioned close to equally between the three wheels.
In any collision the longer more narrow tandem configuration would be subjected to increased forces in a side impact when the vehicle is longer.
While it may not be the best choice of some, I believe it is the best choice for me. It also allows the utilization of the complete front suspension assembly from an early air cooled VW bug, something which makes sense economically. I also want a setup that will spin instead of flip in a severe emergency maneuver.
Another point in favor of the overall length of just 12.5 feet is the ability to park virtually anywhere. My intention is for this to be may daily driver.
I also don't care for the open front wheel configuration where a slight impact might result in severe front suspension damage and potential loss of steering control.

Believe me I seriously considered both configurations, but the real deciding factor is, will my wife actually be willing to ride in this thing!

If the MPG works out to be better than my CBR250R, then I might just sell off all the bikes and my Maxima and we can use her Sorento when necessary.

regards
Mech

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Old 01-10-2012, 04:28 PM   #22 (permalink)
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Quote:
Originally Posted by Old Mechanic View Post
Believe me I seriously considered both configurations, but the real deciding factor is, will my wife actually be willing to ride in this thing!
regards
Mech
She may not ride in it anyway. I can hardly get my wife into my Gen 1 insight. Of course her "embarrasment" factor gets to high when I push it to start it downhill from our house

I really enjoyed reading your post 18 above. I think you might well be onto something worthwhile. At the least, it is an extreemly interesting project!
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Old 01-10-2012, 05:06 PM   #23 (permalink)
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LOL Jim I broke her in (the wife) riding in my Insight. She is used to the weird factor now, at least to the point where SHE drove the Insight for a week when her Rogue got bumped and needed bodywork. Bless her heart, she even managed 56 MPG driving the Insight for a week, while my average was 67 for close to 30k miles.

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Mech
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Old 01-10-2012, 06:32 PM   #24 (permalink)
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Okay, it sounds good. I have a few more questions though

Do you have any more sketches, or even a side view orthographic drawing? It's interesting but I'm a very visual person and am trying to imagine what it looks like.

Second, will you be "filling up" on compressed air before a journey like a BEV charges, or will it be a self-contained system like a hybrid?

Last, what will the wheelbase be? It looks like it'll be too short for a really stable, non bouncy ride. My parents won't ride in my '81 Rabbit because of its loud exhaust and stiff suspension. Hopefully your prototype avoids these!

Thanks!
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Old 01-10-2012, 07:00 PM   #25 (permalink)
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How do you deal with reaching the maximum pressure of the accumulator? Presumably you'd vent to a low-pressure supply, but I think your ability to slow would be affected. I would consider keeping friction brakes (perhaps just on the front wheels) as a backup.

Neat ideas. I'm looking forward to seeing how they work in the real world!! Major major kudos for having the ideas, and then following through by building something based on them!!!

-soD
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Old 01-10-2012, 08:12 PM   #26 (permalink)
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Mech, I very much support your build. I've built a number of cars with the VW front end, and it is a great solution. I recommend the balljoint over the kingpin - pay attention - the beams have different center to center distances.

I kind of wish my car was side by side, and I thought long and hard about it, but it has mostly ended up a tandem project. We mocked up our body, and we are laying fiberglass this week.
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Old 01-10-2012, 10:02 PM   #27 (permalink)
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The front suspension will retain the original braking system. Later I will add a rear disc braking system as a backup in case of hydraulic failure.

Wheel base is calculated at 92 inches not very different from n=many small cars today.
The is no air in this design used for power, it's hydraulic fluid driven.

I have not drawn anything else yet, but will post any further drawings here when they are completed. The outside shape was precisely the same as the aero template used on this forum to show where shapes do or do not allow air flow to not be separated from the body. It was actually designed from the outer shape inwards. Another benefit from the shorter wider shape is less surface friction between the air and the body, an potentially less effected by crosswinds.

A side view drawing is next. It will be basically flat from the lowest portion up 18 inches, with 6 inches of ground clearance for a total of 2 feet from the ground up to the point where you arm rest would normally be in your car (about parallel with the top of the front tires). After that the shape will be identical to the shape of the sides in the drawing. The 18 inches of vertical body side will be two horizontal parallel tubes with fairly heavy sheet metal welded to the parallel tubes and will look just like a NASCAR frame.
All tubing will be of similar strength to race car tube chassis, in the main area of the passenger compartment. In front of the front axle the tubing will be much lighter and the nose cone will be filled with foam to provide a collapsible nose cone. The rear top tubes will be smaller and thinner.

I have a 2001 Yamaha R1 donor motorcycle for the rear suspension.

Most likely the doors will be of a gull wing configuration.

The shop I am working with builds race cars so they have much experience in the process, including bending tubing as well as a superb welder whose work is absolutely beautiful. I am fairly good as a welder but their man is a real artist.

I may use the interior of the tubing for storing low pressure fluid.

If there is an overpressure situation SOD, then the high pressure fluid will be bypassed through a restriction, to the low pressure circuit to provide braking energy in the drive wheel, of course with backup in the front suspension.

The front wheels will either be configured similar to the early Insight, or have skirts that are controlled by the steering rack to move out for clearing the front tires.
Thanks for the support drmiller. I understand the frustration when dealing with "tail gunners" in your build thread and have experienced many similar responses to my idea. I invite constructive criticism from anyone interested here and truly hope everyone tries to learn and understand what I am trying to do with this design.

Maybe one day it will be accepted by the manufacturers but it will probably take a lot of time, possibly more than I have left on this earth, who knows. The history of auto manufacturers has been unkind to real innovation.

In 2006 I read the EPA's hydraulic hybrid research documents and they were begging for a "clean sheet of paper" design for a drive.

I believe this is that design and the Tech students agreed with that assumption. They looked at it for almost a year and did considerable research, far beyond my capabilities.
Thanks to this site and many members here who have helped me to learn how to best utilize aero design in this vehicle and maybe by this time next year it will actually be on the road. God only knows how many miles I would drive it if it does, but my first passenger will be my 90 year old Father, so he can see the Kid done good.

From start to finish (if it ends in the next year) the whole process will have taken over a decade and over $50,000. Wish me luck.

regards
Mech
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Old 01-11-2012, 09:59 AM   #28 (permalink)
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I don't fully understand how your engine works, but I'm definitely going to follow your build thread closely.

Off topic, but what holds more energy per weight and/or per volume, a battery or a compressed air tank?
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Old 01-11-2012, 02:27 PM   #29 (permalink)
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Quote:
Originally Posted by Ecky View Post
I don't fully understand how your engine works, but I'm definitely going to follow your build thread closely.

Off topic, but what holds more energy per weight and/or per volume, a battery or a compressed air tank?
Hi Ecky,
According to wikipedia NiMH batteries are about 75 wh/kg and 300 wh/l
Litium Ion batteries are 200 wh/kg and 400 wh/l
An air tank at 300 bar is about 140 wh/kg and 55 wh/l
I couldn't find comparable numbers for commercial accumulators. Experimental hydraulic automotive systems only claim about 3 wh/l. The experimental UPS hydraulic hybrid claimed 2.5 wh/l at 7000 psi. (480 bar = 48 Mpa))
Gasoline has about 13000 wh/kg and 9400 wh/l
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Old 01-11-2012, 09:54 PM   #30 (permalink)
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i know very little about hyd. any way i really don't know the internals of a "pressure washer" pump. but i guess it has some type of fixed displacement that relieves itself back to suction or has some type of varible displacement? i was wondering if varible pumps would help or do you need a constant displacement? i've done a little work with some multi-piston pumps with a swash (spelling?) plate and they are amazingly effecient (i thought). just stickin' my nose in

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