CUBE per Speed: In my case, (Major east coast pipeline outage), the concern was with energy used on a trip proportional to cube of speed. I was trying to get my wife to slow down from 70 to 55 to make most of the 32 mile daily round trip for chemo on battery in her (30 mile) plugin-Prius and not use -any- gas. (70 to 55 would save HALF the energy (due to drag) for the highway portion). Bob
On Sun, May 16, 2021 at 3:50 PM Robert Bruninga <[email protected]> wrote: > > Although drag Force goes up by square of velocity, but then power equals force > times velocity, so the power to move in the presence of drag goes up as the > Cube of velocity. > > On Sun, May 16, 2021 Peri Hartman via EV <[email protected]> wrote: > > > > square of velocity. But, yes, not linear. > > > ------ Original Message ------ > > From: "Robert Bruninga via EV" <[email protected]> > > Subject: Re: [EVDL] The state of EV's 1890 to 1922 > > > > >Bingo, I re-read my email and when I said it goes up significantly > > >above 45, I omitted the fact (that you allude to) is that it goes up > > >as the CUBE of velocity., A huge factor. Bob > > > > > >On Sat, May 15, 2021 at 9:47 PM paul dove via EV <[email protected]> wrote: > > >> > > >> None of that changes physics. You can lower the impact by aerodynamics > > >> but it still goes up proportional to speed and yes they aren't linear. > > >> the faster you go the faster the drag increases. Rolling resistance goes > > >> up as well but it is linear. I did a calculation for my conversion and > > >> the areo loading caught rolling at around 70mph with a dramatic change > > >> in the curve around 45 mph. It was a Toyota Celica so pretty good > > >> aerodynamics. I have the spread sheet somewhere if anyone is interested. > > >> It required about 21Kw at 70 mph. > > >> > > >> On Friday, May 14, 2021, 4:56:48 AM CDT, Paul Compton via EV > > >> <[email protected]> wrote: > > >> > > >> On Fri, 14 May 2021 at 03:28, Robert Bruninga via EV > > >> <[email protected]> wrote: > > >> > > >> > Wind drag only becomes significant beginning at about 45 MPH > > >> > > >> Tell that to a cyclist. > > >> > > >> This was something that automotive designers used to say years ago and > > >> what they meant was... > > >> > > >> We have so much engine power available, that aerodynamic drag isn't > > >> affecting vehicle performance until you exceed 45mph. > > >> They weren't much concerned with fuel economy. > > >> > > >> Motorcycles have truly horrible aerodynamics,but some attempts at > > >> improvement have been made over the years. The Royal Enfield > > >> Dreamliner was one example and as well as top speed and economy, it > > >> actually improved acceleration, despite a 40 or so pound weight > > >> penalty. > > >> > > >>https://www.oldbikemart.co.uk/the-dreamliner-lives-on/ > > >> > > >> -- > > >> Paul Compton _______________________________________________ Address messages to [email protected] No other addresses in TO and CC fields UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/ LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org
