Fairings

[Quicken]

When I was out on my bike earlier today, I started to think about fairings. Surely they would make a lot of sense on pedelecs, I thought. I know they are more commonly seen on recumbents, but you do get upright fairings. I have found a couple of companies selling them so far, but they are both in the US:

Title
MHP fairings for the Upright Bicycles

Has anybody else thought about fairings for e.g. the Torq? They should make cruising at high speed easier, and possibly give greater range. Also, does anyone know of a european producer of non-recumbent fairings?

Cheers,
Q

 

[flecc]

A derestricted Torq running at full speed would definitely benefit from a pointed fairing, especially if running in a fairly flat area. It's doubtful if bikes running at up to around 14 mph would gain enough to offset the losses elsewhere due to the extra weight, especially when hill climbing when weight is most important.

I'm not impressed with those rather blunt fairings though. Those used on the Continent and in Holland especially on enclosed trikes of various kinds tend to be more sharply profiled. The other thing is that those on that site cut off too low and there would still be quite a lot of body and head drag. From motorbike experience with flyscreens and fairings, that height of screen would only force the air above the body mass from about 60 mph and would be most effective at 80 mph when they create a forward pull behind the body. Those would be fine with drop or low handlebars though.
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[coops]

Torq fairing ideas?

I started thinking about a "non-standard" 2nd or backup NiMH battery for the Torq, to make it easier to carry in addition to the standard battery i.e. less of a heavy & awkward "brick" - maybe something like Jeff (Grandad) did for his Twist, but with a 36V battery divided in two & positioned either side of the rear wheel like panniers, so balanced & the weight distributed so less brick-like (each half weighing around 2.5kg), but then my thoughts also turned to fairings for improving aerodynamic efficiency i.e. reducing air resistance at higher speeds, as a means to possibly reducing power output & increasing range for the same speed without a fairing.

By my reckoning, on my Torq 20mph requires about twice the power output that 16mph does, and around 80% of the power is used to overcome air resistance: if a fairing could reduce power output by say 20-25%, that would give around 25-33% more range for the same speed, hopefully

I'm aware its a bit of a fuss for a few mph, and I'd get there in around the same time at 15mph, but it'd be good to know I can put in a burst of speed if required, without too much loss of range, or cruise a few mph faster if I want .

Anyway, a websearch didn't throw up much beyond what you posted Quicken, but I came across this other forum thread on fairings & having been not over-impressed by all else I quite like the look of the "pocket bike" fairing: maybe its a bit overkill for a Torq & I've no idea of its weight, but find one the right size, shape & weight for a Torq & find a means to attach to the bars and it might be worth a shot?

It took me a while to figure out how its attached, but if you look at the 2nd photo posted May15th, it looks to me that the "bar ends" used to mount the fairing are attached to the handlebars just inside the hand grips and are pointing almost vertically down - maybe the 4 screws forming a vertical line down the side of the fairing, visible in the side view under the left hand grip, hold the fairing to the bar ends. It'd need to be fixed very securely to the handlebars, but to me that looks a good solution & quite a strong mount.

Stability in crosswinds is an important safety factor, but if the fairing isn't full length & the side profile also isn't too wide then it should be ok, plus the Torq's weight is an advantage in this respect I think?

Other thing is rattle from the undamped front wheel - I don't know how that would affect things?

So, is it worth a shot do you reckon, or too much pain for too little gain?

Stuart.

 

[flecc]

I think the deciding factor is hills.

This echos the Dutch situation with Velomobiles. In their flat country with lots of headwinds over the plains, those heavy but fully faired pedal vehicles are brilliant. But in our hilly country they are just impractical and are slower than anything else.

If you're in the Eastern Counties, the Somerset levels or the central England plains a fairing could pay off well, but in the North or South Downs, the Peak district or the like, a fairing's weight would cause losses far greater then any downhill gains.
.

 

[coops]

Yes, that did cross my mind flecc. Not a mod you'll be in a hurry to do then? you'd be much more likely to improve efficiency by other means, like good gearing etc. in your area I suppose how's your project coming along? Should I start a "whats flecc been up to" thread in anticipation of an announcement, or would that be premature?

I must admit, I'm not sure how well a small and "home made" fairing will reduce drag & hence power output, even while riding in a "tuck" type position - not easy without drop handlebars - and I'm also not sure how best to test if it works, or how well. It's also not the easiest thing to make a mock-up of, so I think I'll start by looking out some useful "bar-ends" which can be adapted to fit a fairing to & see where that gets me.

 

[Ian]

Here's some food for thought, and more from the same company here. Although intended for motorcycles, the idea, or even the product may well be adaptable for use on bicycles. The company do have a UK distributor here.

In spite of the extreme lengths that designers go to to reduce drag It's interesting that fairings are rarely seen in bicycle racing other than on recumbents. The only one I ever saw was a tiny screen on the handlebars of a downhill MTB that subsequently went on to exceed 100mph on a steep ski slope. It could be that the racing rules don't permit fairings or it could be that the designers consider that the weight penalty outweighs the aerodynamic gains.

I started thinking about a "non-standard" 2nd or backup NiMH battery for the Torq, to make it easier to carry in addition to the standard battery

An Idea suggested a while ago by Flecc in another thread was to re-cell a standard battery with C size cells, such a battery would be about half the capacity and weight of the original but would give a very useful extension to the standard range.

Ian

 

[flecc]

Yes, UCI racing rules don't allow fairings, they are an extremely conservative bunch.

The big problem with cycle fairings for us is that they need to be the whole size of the rider as there is no worthwhile deflection at our speeds of up to 25 mph.

I know that from practical experience with both fairings and flyscreens of various sizes on my motorbikes over the years, and as I've mentioned above, they really only come into full effect at approaching 80 mph. It's interesting that many car designers insist the same about streamlining on car bodies, saying there's little benefit below 80 mph. Equally, the front and rear spoilers on formula one cars do nothing useful below that speed either.

Some Windcheater recumbent trike users say the main benefit of their fairing is weather protection, which may also support the above to some extent since those machines can reach 75 mph downhill.
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[flecc]

how's your project coming along? Should I start a "whats flecc been up to" thread in anticipation of an announcement, or would that be premature?

Been ready for ages and been preparing web pages and a 13 page PDF. I've held back for the F series announcement, and currently for Presteigne. I believe also that Tim wishes to say something about a waterproofing modification?

Can't disrupt the normal forum business with my hobbies after all.

Suffice to say the the Twist is laid up at the back of the garage and I haven't ridden the Torq for four weeks, and can't see me doing so at the moment.
.

 

[coops]

Firstly, thanks for the links & new info Ian: food for thought indeed! Some ideas there; a bit pricey by the looks of it, and even more for any custom-build job I suspect, so if I do try out the fairing principle it'll probably be a Heath-Robinson-ish job involving bar-ends and maybe some simple origami involving perspex and then if it works, I'll probably just keep it rather than try to do a more "professional" job .

I think I saw that battery idea with C-cells - was that for a 24V/Twist? I'd considered these & even sub-C too, since they're both smaller & lighter than D-cells, but its as much about how to carry them & how they wire up for power when needed as it is about weight (I'm a bit clueless on the wiring matter): my idea was, to give a good boost to the power & for practicality weight-wise, to split a 36V D-cellpack into two sections of ~2.5kg each, wired together, positioned either side of rear wheel like panniers, and both wired up with the main battery to make one big double capacity battery for extra long excursions, with no battery change needed. Hopefully the "pannier batteries" could be either made to appear inconspicuous or lock to the frame somehow, so as to minimise any theft risk.

Whether that could all be done, I've no idea, nor how difficult it would be, but I'm guessing that currently this would be a NiMH only mod, and may not be useful for Li battery users? Also affordability would depend on NiMH prices...


Flecc: very diplomatic of you to delay announcing your project results, I must say, but worth the wait a bit more involved than the average "hobby"!

Stuart.

 

[flecc]

to split a 36V D-cellpack into two sections of ~2.5kg each, wired together, positioned either side of rear wheel like panniers, and both wired up with the main battery to make one big double capacity battery for extra long excursions, with no battery change needed. Hopefully the "pannier batteries" could be either made to appear inconspicuous or lock to the frame somehow, so as to minimise any theft risk.

Whether that could all be done, I've no idea, nor how difficult it would be, but I'm guessing that currently this would be a NiMH only mod, and may not be useful for Li battery users? Also affordability would depend on NiMH prices...

Yes, definitely an NiMh only mod Stuart. They can be run in parallel in this way, but they must never be charged in parallel.

My C cell suggestion referred to the 5 Ah cellpacks sold by Batteryspace in the USA. It seems though that there is a question mark about this company's sourcing and quality control, so it might be best to check if another supplier like battery-force.co.uk have them.
.

 

[prState]

Reviving this thread. I was looking at the zzipper site the other day in fact.

What I'd really like in a fairing, is a hard material fairing (plexiglass or whatever they make it of) that comes off with a few clamps or twists and then folds up for storage in small carry bag.

If you could stretch a material over the front surface after unfolding, that would cover the problems with not having a smooth surface. An alternative might be an unbrella type device that you can unfold and then stretch the material over the surface of a frame.

I'm surprised they weigh much. I'm looking that surface area of a an old motorcycle face shield I have(not sure what the area measurement is) and it's pretty light.

(in unrelated news, my inner tube blewup at starbucks today while my giant was parked. Could it be I filled it last night inside at 78 degrees, and it was probably over 105 out there? Hmm. Older tube too didn't help)