07-24-2017, 10:57 PM
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#21 (permalink)
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Master EcoModder
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Quote:
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.
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Do you have pictures or additional hand-waving to explicate this?
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Today
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07-24-2017, 11:04 PM
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#22 (permalink)
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Master Novice
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Looks awesome. I liked seeing LEDs on the fore edges of the A-arms, gives such a small vehicle a lot more visibility at night. Good.
I also had thought to mention filling in the A-arm triangles to cut their drag: oops! Already done. Super cool. When you're trying to push a 300-lb ride with a 200-lb rider at 60+ and you're using just 125cc, you fill in the triangles!
I wonder if adding discs to either/both sides of the front wheels, and to the rear wheel, would quiet it down/add speed/increase fuel economy? Normally it's played down a bit since it's not a big contribution on something as massive and aerodynamically noisy as a car, but you're already below .10 cD. I think smoothing the wheels would make a pretty darned big difference if you're that low already and still running bare spokes.
Again: beautiful. Keen to see where you go next with your efforts.
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07-24-2017, 11:21 PM
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#23 (permalink)
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EcoModding Apprentice
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Offset for Trail without Caster Angle
Quote:
Originally Posted by freebeard
Do you have pictures or additional hand-waving to explicate this?
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In the side view, the kingpin axis is vertical, and the spindle is offset to the rear by the amount of trail desired.
In the picture the top left feature is the spindle hole, above the steering rod. The ball joints are in the middle, and a rim brake is mounted on the right. There were no apparent complications. Mike Burrows has also used it on a bicycle with no problem.
The use of caster angle instead is a holdover from the earliest cars, which did better with the camber angle this produces in a sharp turn. You can see this taken to extremes now in road graders. It also reduces bearing loads a bit, but now it is somewhat a liability, trying to keep a wide tire upright.
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07-25-2017, 05:31 AM
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#24 (permalink)
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Master EcoModder
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It's hard to see the picture and the description at the same time, but I think I get it. Direction of travel is to the right?
Ball joints are not plumb?
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07-25-2017, 06:54 AM
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#25 (permalink)
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EcoModding Apprentice
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Quote:
Originally Posted by freebeard
It's hard to see the picture and the description at the same time, but I think I get it. Direction of travel is to the right?
Ball joints are not plumb?
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Yes, travel is to the right. The picture is from a slight angle toward the front, so a bit of the front-view offset on the ball joint shows up, along with a not-level frame, but the ball joints are plumb, AFAIK.
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07-25-2017, 10:08 PM
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#26 (permalink)
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Amazed..
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Ecomodder Feature...humbling, thank you!
Hey Guys! Just wanted to take a minute to say THANKS for your thoughts and input... I was a little nervous about going public after 7 years of hiding...and you all are making me feel so at home... Couldn't believe it today when I checked my email and saw that our little buggy was featured...
Clearly stated, I think (I know) that you guys are the cutting edge, and deeply respect and admire the experience and efforts of the folks who sit around this amazing table. I actually feel a little stupid for not having the nuggies to put it out there earlier for your awesome advice!
Know that I am listening closely and humbly, while trying to get ready to prepare and sell the kit versions very soon. Ecomodder...rocks!
Honored and Proud.
Ray
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07-25-2017, 10:25 PM
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#27 (permalink)
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Amazed..
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Hey freebeard!
To my knowledge, Volkswagen holds the record for production at about 260 Mpg. Craig Vetter's group, The Craig Vetter Fuel Economy Challenge (craigvetter.com) is the real point of the spear with gas, diesel and electric streamliners and such in my opinion (They were doing 400 Mpg in the 70's!).
Currently, and oddly, some of the older Guinness record's have been removed for economy. An example is/was "The California Commuter", at 155 Mpg, in 1980...
There is also a guy named Vic, who frequent's Craig's stuff and ninjette.org, he just broke 260 Mpg on a simply faired Ninja 250...and that is serious!
Oh Bonneville...sigh. Got to walk on it last year...terribly humbling. We are working on a long tail version to get out there and play with the big boys by maybe 2020...but you are right, they don't play about scrutinizing for safety. We'll see. (Oddly, you wouldn't believe how often folks ask about this!)
Gonna take a look at your links and am very grateful for the sharing.
On the spats, we are working on downforce and geometry right now, and can't put the pants on till we are very firm at high speed. They act like rudders...and we only weigh 350lbs.
Quote:
Originally Posted by freebeard
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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07-25-2017, 10:31 PM
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#28 (permalink)
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Amazed..
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Quote:
Originally Posted by Ecky
Where'd you get the canopy?
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Todd's Canopies made this one and a few other prototypes for us...he was AMAZING!! Todd unfortunately passed and his family closed the business last year. We are beginning dev work on our own canopies in two days (Cross fingers) There are other folks that I will happily share if you would like.. LPAERO.com is the big boy from what I have seen...
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07-25-2017, 10:40 PM
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#29 (permalink)
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Amazed..
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Quote:
Originally Posted by California98Civic
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.
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Thanks so much California98Civic...kind words. The guys calculated CDa on the body alone, I think..RR and wheel drag has not been calculated yet. Essentially, the body is in flight at 7" ground clearance...with very little ground effect, mostly to counteract lateral gusts...and that part works well, in spite of screwing with roll center and CG. We are putting pants on later, after we get a little further on downforce with minimum drag. The A Arms are actually covered and profiled in the rear to a neutral wing.. I will tell you, after over-correcting for 7 years and repeated lessons/failures, I'm going real slow on change/add...baby steps. We do the highway testing near the ocean, and the headwinds can easily gust to 30kts...which is 100 actual at 70 mph :-) Thanks again...
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07-25-2017, 10:46 PM
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#30 (permalink)
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Amazed..
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Quote:
Originally Posted by ECO-AKJ
Where did you get the lighting on the front of the exterior, I am liking that setup!
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Hey ECO-AKJ, after getting cheated on Ebay a few times on quality, we now get everything from Superbrightleds.com. They sell all kind of strip lights and other stuff. The headlights a High output from them as well (With heat sinks :-) I think we are about 5 amps draw for all body lights now.
Thanks for the compliment! One of the team engineers, Ned Ryan Doyle, calls it "The Black Bolt"...he is a very cool guy :-)
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