07-07-2017, 11:27 AM
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#11 (permalink)
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Amazed..
Join Date: Jun 2017
Location: Asheville, NC
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Happy Friday everyone!
Stubby79- Would love to have you as the first owner!!
Old Tele man- You pegged it, design completely based on Salt Flats belly tank racers..
ar5boosted- Totally agree on artwork color scheme on the next one...This one will be covered in sponsor/supporter logos pretty soon. (And as a fellow old timer, I totally agree on perceptions being real enough!)
Here are some more pics.. Will start a build/work thread soon if okay...
Have a great weekend,
Ray
Last edited by Alien Vehicles; 07-07-2017 at 11:28 AM..
Reason: Spelling!
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Other popular topics in this forum...
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07-07-2017, 04:20 PM
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#12 (permalink)
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Master EcoModder
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It looks like a nice effort. What sanctioning body's record are you going for?
Where does the 0.089 Cd figure come from?
This is the most informative. After the first pictures I thought you'd cut a full teardrop canopy in half. Do you think it would be possible to put sprockets on the top of the kingpins and run a chain inside the upper A-arm?
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07-08-2017, 02:22 PM
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#13 (permalink)
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Amazed..
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Quote:
Originally Posted by freebeard
It looks like a nice effort. What sanctioning body's record are you going for?
Where does the 0.089 Cd figure come from?
This is the most informative. After the first pictures I thought you'd cut a full teardrop canopy in half. Do you think it would be possible to put sprockets on the top of the kingpins and run a chain inside the upper A-arm?
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Hey Freebeard! Thank you... Well, I'm not real smart when it comes to the sanctioning body stuff...planning on going for Guinness, and then just publishing our work with witnesses on our pr stuff...
On CDa, I'm not the Aero geek in the project, but the two guys that are did the math by hand...calculating square frontal area with laminar flow. Their numbers were actually (.087-.089) at 60 mph. They say it gets better past 100...but I don't think I'll be trying THAT this week!
Totally lost me on sprockets on the kingpins and chains in the A Arms???
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07-08-2017, 10:04 PM
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#14 (permalink)
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Master EcoModder
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Small-f freebeard, I'm not that important.
What's the current Guiness record? I really don't follow them.
Generally, with sanctioning bodies, the rules determine what can and can be done. Of course, the most unbounded would be your inspiration — Bonneville. You could look into whether you can pass scrutineering there.
You might review the materials at http://ecomodder.com/forum/showthrea...html#post87799. I don't car to dig through it myself, but generally a free body in ground effect can have a Cd of 0.05-0.09. See also http://ecomodder.com/forum/showthrea...tml#post289064
Once you add fully spatted wheels (three or four) it's hard to reach 0.12. When you figure in the open front A-arms it goes north of that. You might send a Personal Message to aerohead and invite his comment. I think he would like to see it.
That other thought was unpremeditated. If the top of the kingpin passed through the upper Heim joint or whatever to a sprocket, then a chain running in the hollow upper A-arm would allow eliminating the drag from the steering arms and the drag link/idler arms (or whtvr). Those small round tubes probably have as much drag as the A-arms which are thicker but have a better fineness ratio.
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07-09-2017, 03:41 PM
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#15 (permalink)
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Master EcoModder
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Where'd you get the canopy?
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07-10-2017, 11:04 AM
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#16 (permalink)
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Cyborg ECU
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Kudos on such a good looking and working build! I think the wheels, the front arms connecting them to the body, and their lackof fairings mean the Cd your people calculated is probably optimistic. Looking for fairings for those wheels and arms is definitely one of the key places to improve that disappointing 69mpg you just recorded. Right now those tires and wspoked wheels are giant spinning mess-fans mucking up your aerobody's pretty nice shape.
__________________
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.
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07-10-2017, 11:43 AM
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#17 (permalink)
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Focused on MPG
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Where did you get the lighting on the front of the exterior, I am liking that setup!
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Staying Focus'd on MPG
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07-15-2017, 08:43 PM
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#18 (permalink)
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It's all about Diesel
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That's an interesting project. I have already considered to attempt something similar and try to register it as a road-legal vehicle.
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07-24-2017, 01:33 PM
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#19 (permalink)
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EcoModding Lurker
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I'm not that familiar with the 250 Ninja. Is that EFI or carbureted? MPG in the 70's might be due in part to enrichment. I think one of the later Megasquirt incarnations or something similar should be up to spark and fuel and would allow you to monitor what is going on with the engine. Gearing is another factor. What is the RPM at your targeted cruise speed?
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07-24-2017, 03:15 PM
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#20 (permalink)
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EcoModding Apprentice
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Thanks for posting, Ray. Kudos on going lightweight. I don't go to Facebook for anything, since they pretty much destroyed the functioning listservs without replacing their usefulness. As far as I can tell, nothing I posted there was ever seen, probably because I had not done whatever it takes to target my ads.
With the rear engine, I think you will have problems with crosswind stability, and they will get far worse if you add fairings to the front wheels. Those are currently adding about 50% to the drag. Beware of the fairings being unstable themselves, as the most obvious shape puts the CP ahead of the kingpin axis. If you have to, you can just offset the kingpins and spindles to get trail for both steering and aero instead of using a caster angle. It works fine.
You really need to do a coast-down test, and find out what your power requirements are. Timing several points lets you separate out rolling and aero drag. It would also be nice to get the weight distribution and CG height, which can be calculated by weighing the front and rear with each end lifted in turn.
There is a great account of the test results on a WWII fighter aircraft, from the original shape to one with cooling vents, guns, and other little details. The drag doubled. The devil is in the details, covering all spokes and managing the flow in shear between moving and stationary parts, minimizing or fully sealing openings, gently ducting and closely regulating the cooling air, etc. Laminar flow is very seldom present on road vehicles, as the slightest blemish or irregularity trips it to regular turbulent flow, spreading out at 30 deg from there back. The back wheel looks nice, but expensive on fuel.
The windshield/roof will bake you on a sunny day, and the angle somewhat impairs vision, especially if there are any manufacturing defects. It will need a defroster, being hard to reach, and an outside wiper that won't scratch it with road grit.
If you are using 17" wheels, you might be able to pry loose a set of Michelin solar race car tires, which would probably halve your rolling drag. Maybe we should set up some sort of petition or PR campaign to make those generally available.
Last edited by Bicycle Bob; 07-24-2017 at 06:31 PM..
Reason: Noticed the second page, and thought some more.
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