tag:blogger.com,1999:blog-7497191769424400596.post5553357627762074267..comments2024-03-05T00:21:36.018-08:00Comments on The Left-handed Cyclist: Make My Velomobile a Quad!Hephaestushttp://www.blogger.com/profile/16913388668135150291noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-7497191769424400596.post-64757359501248562852015-11-11T03:48:46.476-08:002015-11-11T03:48:46.476-08:00I was thinking about rolling resistance and not ro...I was thinking about rolling resistance and not rolling over resistance. My mistake. Sorry for that.<br /><br />It's obvoius thing that flipping trike is much easier than quad. You don't need any calculations for proving that.<br /><br />Apart from being more stable there is more things to consider: cargo space. In delta configuration You might be able to carry more cargo (than in tadpole) but due to the more weight of the whole setup (cargo gives extra weight) You need to have very good brakes. Two braking wheels in front vs one braking wheel give tremendous difference:<br /><br />https://picasaweb.google.com/lh/photo/hUnrXP1EuvIQfyC7l23sfNMTjNZETYmyPJy0liipFm0?feat=directlink<br /><br />Braking distance from 100 km/h to zero is shortened by 1/4 (40m vs 30m). This is huge advance. Stable, cargo-capable, good braking vehicle ... should be quad.Maciej Dlugoszhttps://www.blogger.com/profile/15524749535193219789noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-71378222932445135702015-11-10T17:15:08.814-08:002015-11-10T17:15:08.814-08:00Dear Mr. Dlugosz, thank you for the lecture on pol...Dear Mr. Dlugosz, thank you for the lecture on polar moments of inertia and rolling resistance. I am aware of the phenomena. Unfortunately, you misinterpret the crux of the post. My concern is will the resistance to flipping the vehicle during turns, not rolling resistance. Call it cornering ability. Any rider who has flipped a trike over in a turn would be more concerned with those effects that a bit more rolling resistance. And the polar inertia effects are conservative (as opposed to disapative). I was aware of the four-wheel Quest but I thought it was a two-seater.Hephaestushttps://www.blogger.com/profile/16913388668135150291noreply@blogger.comtag:blogger.com,1999:blog-7497191769424400596.post-83607691070553789262015-11-06T01:26:59.521-08:002015-11-06T01:26:59.521-08:00I think You make mistake assuming that adding extr...I think You make mistake assuming that adding extra wheel to 3-wheeler to make it 4-wheeler) adds 1,5x rolling resistance. Rolling resistance depends upon weight on the wheel. In case of 4 wheels weight is distibuted across more wheels so less per one wheel. Let's say 3 wheels 120 kilograms means 40 kilogram per wheel. 4 wheels 120 kilograms means 30 kilograms per wheel. Summarize each rolling resistance and You will get almost the same. Of course adding extra wheels means more weight. But looking at whole unit (velomobile + rider) it is tiny amount of extra weight for an extra wheel. There is a catch: in case of velomobile it is rare to get even weight distribution across front and rear wheels. So it means more mathematics. Let's say 40 weight on front and 60% at rear. Adding extra wheel in this case lessens rolling resistance but not "in linear" way I described above (by simply dividing weight per number of wheels). I hope You get it..<br /><br />Now the "perceived problem" with adding extra whels for every biker is that it means more inertia. Rotating inertia and non rotating inertia. In case of 4-wheel vehicle it will be slower to accelerate such vehicle than 3-wheeler. It also means that 4-wheeler (4 wheels spinning instead of 3, each rotating wheel has rotational inertia) will be harder to slow down. So what riders feels as "more resistance" when addinhg extra wheel is not rolling resisatnce multiplied 1,5x but more (rotational and non rotating) inertia.<br /><br />I wonder if You know that Quest already produces 4-wheeler:<br />https://velomobiel.wordpress.com/2015/10/28/quattrovelo-prototype-rides/<br /><br />There is also another 4-wheel velomobile being developped, Sunrider:<br />http://mooigeelisnietlelijk.blogspot.com/2015/11/in-het-duister-tasten.htmlMaciej Dlugoszhttps://www.blogger.com/profile/15524749535193219789noreply@blogger.com