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[Richard230]

I think you will find this article interesting. In particular, I liked this quote:

It may come as a shock to most motorcyclists, particularly those used to reading boastful claims in motorcycle advertising to the contrary, but 99% of motorcycle OEMs don’t give a damn about aerodynamic efficiency. The reason? It’s such a lost fight that it isn’t worth the effort.

http://canadamotoguide.com/2016/05/04/motorcycle-aerodynamics/

[Badness]

One fellow on here put a cafe style fairing and noted that he gained an extra 20% distance from his bike , now that's got  to be a good deal.

[T.S. Zarathustra]

A little rant here . Most people buy bikes based on looks, color, or brand. Just look at all the ugly (in my humble opinion) KTMs and Yamahas that look like a blind kindergartner added bits with a hot glue gun. People don't really care about aerodynamics and overly aerodynamic bikes with streamlined fairings don't stand a chance.

[BrianTRice@gmail.com]

First of all, let's make sure to cite Electric Terry who has set a number of records on a streamlined Zero using the Vetter design:
https://en.wikipedia.org/wiki/Terry_Hershner


Personally, I think the very first design that Terry fielded was the closest to being attractive and marketable. That long fishtail broke records but was not the sort of thing one could wield responsibly in a parking lot. Also, the Vetter design has never accommodated a passenger or looked like anyone could just sit in it safely.

My prior dustbin build netted a 20-25% improvement over stock, and it wasn't that optimal at all:
http://electricmotorcycleforum.com/boards/index.php?topic=6591.msg52197#msg52197

I can say for sure that any discussion of dustbin fairings is based on outdated technology and assumptions. The original dustbin racers were "torpedo bikes" with the rider crouched low almost within the fairing, and the suspension and old tire compounds were drastically underrated for the designs. On my DSR, a dustbin is just a nose cone and has not been a problem, even in stormy weather over bridge expansion joints.

When balanced with a tail, the CP-CG relation isn't perturbed, and tail design actually dominates drag concerns - unfortunately, tail drag optimization is severely under-explored. Vetter's designs are the only major instances outside of landspeed record attempts, and they're just a series of one-off prototypes and garage builds, not sufficient to consider production candidates by any means, for a number of reasons around safety and ergonomics.

I'm currently using a Hollywood Electrics sport touring fairing which nets 15-20% highway range improvement and looks good and fits the design of the bike:
https://www.facebook.com/groups/zmcowners/permalink/1668738283195373/

While styling and marketing is a major challenge for streamlined motorcycles, I think the majority of the stumbling block has been generally in the nature of the rhetorical posture of advocates, who generally come off as finger-wagging. Fuel efficiency as a virtue doesn't sell.


What we need is an efficiency solution that is easy to acquire and use, attractive, and flexible to meet a number of needs and aesthetic preferences.


As electric motorcyclists, we want more highway range, and efficiency improvements are the most economical way there. Any battery improvements ramp up costs, weight, size, and charge time proportionally, whereas a well-designed fairing can make an electric motorcycle produce less heat while traveling at the same speed, and change the ratio of charging time to ride time.


My current setup gets 135 miles of range on the highway at 65-70mph. That's a 2016 DSR with Power Tank and the Hollywood Electrics fairing. I'm currently aiming to achieve 150 miles of range at the same or possibly higher speeds with a new fairing, and 150 miles of range with a 1 hour charge time is a nice set of numbers for making electric motorcycle travel really appealing.

[Michael Moore]

FWIW Guzzi did not have problems with stability from their dustbin fairings.  People who said "let me cobble something together that looks sort of like that" and who didn't have a wind tunnel and the understanding of how to use it did have stability issues.

From what I've read the FIM ban on the full streamlining was part of an overall "let's break the power of the factory teams" move.  "Dustbins are dangerous" was not true then and not true now.  "Some dustbins that are poorly designed are dangerous" was true then and now.

The FIM ban was a case of throwing the baby out with the bathwater.

Very low drag vehicles can be less stable than those with higher drag.  There's a reason why at Bonneville they don't run if crosswinds are higher than several miles an hour.  Those vehicles are not meant for real world road use.



shows that a Creasey Voyager with large amounts of bodywork meant to give improved mileage and comfort from better aerodynamics can deal with disruptive side winds.

As with many things in motorcycling, with aerodynamics there's a lot of what "everyone knows" that isn't actually true.

Also, as Tony Foale elucidates in his book, you have to be cautious with applying 4-wheel automotive aerodynamics to two-wheel vehicles.  The latter lean, the former don't, and the chassis dynamics can be quite different.

cheers,
Michael

[Richard230]

Another reason that I heard for the FIM phasing out dustbin fairings was that the manufacturers and racing enthusiasts were not happy about those large fairings as they couldn't see the motorcycles under the dustbins so that they could identify one from another. All the bikes looked alike and both groups wanted to see the machines that they were rooting for, rather than racers that all looked alike and you couldn't tell one from another as they flew past.  Plus, in those days, having the maximum amount of surface area for sponsor stickers wasn't as important as it is now.    With modern computers and aerodynamic knowledge, I am sure that the major racing organizations could approve more streamlined racing motorcycles - if they wanted to, but the fact that they don't do so tells you something. Don't forget, racing is all about the money and not necessarily about how fast you can go.