Simple practicle (cross)wind assist and better aero for any bike

[Logic11]

Sounds nutZ! But bear with me and look at this:

SPOKE FINS

AEROCROSS™ wheels with SPOKE FINS™ streamline the round spoke, substantially reducing drag on the bicycle wheel itself—even in the presence of substantial crosswinds—while providing unmatched crosswind stability and safety to the cyclist in gusty wind conditions. • Laminar Flow MINIMIZES Spoke...

nullwinds.com

Now those are cheap and nasty ass looking things, but the science is legit:
They make the spokes more aero and the bike less susceptible to crosswinds.

Imagine a strong crosswind at 90 degrees to your direction of travel.
NB that when one of those fins is on the rising spoke that happens to be parallel to the ground; gravity is pulling that fin down a bit, so there's (wing type) lift helping the back of the wheel to rise... spinning the wheel forward.
ie: You have a teeny-tiny amount of wind assist.

If these things were proper teardrop/wing-ish shaped things and lightly sprung to return to center so to speak;
then all of them, regardless of position would provide a forward rotational force on the wheel in a crosswind.
ie: Now you have a light, simple and practical wind assist device that doubles as a means of reducing aero drag when there's no crosswind.

Round Bar/pipe Cd: ~1.17​

Aero teardrop (wing) shape Cd: 0.045 (26X lower Cd than round)​

​

It would also ameliorate crosswind buffeting...

IMHO proper aero shaped, lightly sprung doodats made of (carbon look) glass fiber would be 'The Shiz!' and probably sell quite well.

NB that a similar treatment to any vertical-ish tube in the bike frame would have the same effects as above...
ie: For the 1st time: Better aero AND better crosswind stability..!

(The world would be a better place if people didn't 'own' other people's ideas: What are the chances of further idea sharing when that shit happens?)

 

[neptronix]

I feel like on an ebke, we have things like:
- battery
- hub motor or mid motor
- non-skinny rider

Maybe you fixed the spoke part of crosswind buffetting but you barely put a dent in the overall problem.

 

[offGridDownUnder]

you barely put a dent in the overall problem

What we need is a large vertical airfoil suspended from a robust bearing on a beanie cap shrouding the drag-chute/rider to deal with the largest part of the problem.

 

[Logic11]

I feel like on an ebke, we have things like:
- battery
- hub motor or mid motor
- non-skinny rider

Maybe you fixed the spoke part of crosswind buffetting but you barely put a dent in the overall problem.

Hmmm, ye; Not much space for: "...similar treatment to any vertical-ish tube in the bike frame..." with battery packs etc.
It'd be interesting to test though.

For the Sun Tour guys with their square tubing frames holding up Solar panels and the need for efficiency..?

 

[gromike]

Gnat's ass of energy gain.
For anyone trying to catch this thin sliver of energy gain--all the more power to you .

 

[Logic11]

Gnat's ass of energy gain.
For anyone trying to catch this thin sliver of energy gain--all the more power to you .

lol!

Maybe!?
But do remember that the top 3rd of your wheel is moving into the wind at 2X the road speed and aero resistance increases at speed squared.

I also NB that there's already aero oval-ish spokes available for bicycles.

 

[gromike]

I also NB that there's already aero oval-ish spokes available for bicycles.

Yes, for decades:

 

[Chalo]

I also NB that there's already aero oval-ish spokes available for bicycles.

They too are pointless, counterproductive embellishments for biting money away from poser chumps. Not as conspicuously stupid as clip-on louvers for spokes, but still all disadvantages with no redeeming qualities.

Spokes do their job by being under tension. To put them under tension, you have to tighten a nipple at one end. A round wire resists winding up several times better than a flat bar of the same cross-sectional area. So lenticular or bladed spokes reduce the ability of the spokes to do their only job, in return for a claimed benefit that can't be demonstrated in normal use, ever.

But maybe if you sprinkle them with boric acid or something, then they can fulfill their potential.

 

[gromike]

Then I guess the thirty bucks I paid for that bike with the bladed spokes was a waste of money, though it is a beautiful piece of wall art.

 

[Logic11]

They too are pointless, counterproductive embellishments for biting money away from poser chumps. Not as conspicuously stupid as clip-on louvers for spokes, but still all disadvantages with no redeeming qualities.

Spokes do their job by being under tension. To put them under tension, you have to tighten a nipple at one end. A round wire resists winding up several times better than a flat bar of the same cross-sectional area. So lenticular or bladed spokes reduce the ability of the spokes to do their only job, in return for a claimed benefit that can't be demonstrated in normal use, ever.

But maybe if you sprinkle them with boric acid or something, then they can fulfill their potential.

The point is this:
Round Bar/pipe Cd: ~1.17
Aero teardrop (wing) shape Cd: 0.045 (26X lower Cd than round)

If that 26X lower CD weathercocks to always face into the wind; you get lower Cd and less crosswind buffeting.
If lightly sprung; you get a tiny bit of free thrust.

NOWHERE do I recommend those ass plastic clip-on things.
They are simply about as close as I can get to a visual example of what I am on about.

The problem here is:
Reading with the intent to reply, rather than understand...

What you are doing is deriding an idea.
Had humanity's inventors tucked their tails between their legs and slinked away upon encountering you; you would be walking too and from your cave.

I challenge YOU to come up with a new idea that might do triple (what I like about it) duty to:

• Harnesses free energy to sometimes improve the efficiency of a bicycle.
• Improve the aerodynamics.
• Improve the safety.

of a bicycle or E-bike by even a hair.

I know: You "don't need to come up with no stupid ideas"
Yet you aren't living in a cave and walking where you normally ride, are you..? You're riding other inventors' shirt tails.

Might I suggest you go find the Freegen Hub Motor thread.
That's another 'simple' idea that does multiple things for you to take multiple dumps on.

 

[fechter]

Don't forget the force applied to the bike will be a function of the CD x the frontal area. Spokes don't have a lot of frontal area. I can't imagine getting pushed around by a crosswind due to the forces on the spokes.

 

[Chalo]

Don't forget the force applied to the bike will be a function of the CD x the frontal area. Spokes don't have a lot of frontal area.

Even less because to one degree or another, they "draft" each other. Also, the spokes at the top of the wheel mare the only ones of note, because the front and rear ones are end-on to airflow, and the bottom ones slow to near zero ground speed at their outer extents.

I think it's a clear indictment of gimmicky aero spokes that these days, they almost inevitably occur on plastic bikes with gigantic bloated frame tubes that cancel out any spoke-related drag reduction by multiple orders of magnitude.

 

[Chalo]

Don't forget the force applied to the bike will be a function of the CD x the frontal area. Spokes don't have a lot of frontal area.

Even less because to one degree or another, they "draft" each other. Also, the spokes at the top of the wheel mare the only ones of note, because the front and rear ones are end-on to airflow, and the bottom ones slow to near zero ground speed at their outer extents.

I think it's a clear indictment of gimmicky aero spokes that these days, they almost inevitably occur on plastic bikes with gigantic bloated frame tubes that cancel out any spoke-related drag reduction by multiple orders of magnitude.

 

[neptronix]

I challenge YOU to come up with a new idea that might do triple (what I like about it) duty to:

• Harnesses free energy to sometimes improve the efficiency of a bicycle.
• Improve the aerodynamics.
• Improve the safety.

of a bicycle or E-bike by even a hair.

Hey, i've thought about these things a lot

This below bike has a top speed of 34-35mph on 900w thanks to the huge aerodynamic advantage.

It improves safety by reducing the distance you fall. This bike uses the handlebar as a crush zone in the event of a tipover, so it will eat up gravity on the way down too. I have since fitted some bars to the side that would take even more impact.

I have crashed this kind of bike and had a few upsets at high and low speed. It seems like if you're going to crash, it would involve falling to the side. In this case, as long as we can hang on to the bike during a crash, we can walk away with some road rash at most.

In addition to this, the handling is as such that if you lose control over the front wheel, you can regain it easily. I have super wide handlebars, so it's even more forgiving. On an upright, you have a problem where a significant steering error sends you over the handlebars. This bike has a massive error tolerance and i'd call it 'drunk driveable'. That's a +1 to safety.

I've crashed this kind of bike once and it was the best bike crash i ever had. Just road rash.

2 out of 3 ain't bad. And there's room for quite a bit more aerodynamic improvement.


For an upright bike, it's hard to improve the aerodynamics without making it vulnerable to cross winds. That's because the human center of gravity is much higher, therefore the bike is more sensitive to them. The human shape is also really poor, and aerodynamic devices need to be long to mitigate that. Drop handlebars, like on road bikes, help a lot. A small fairing on the handlebars may help. Being skinny helps. A tail fairing helps. An ideal frame shape helps.

After all that effort, your bike still isn't as aerodynamic as the semi recumbent bike pictured above, but you have made a decent dent in the problem. Hopefully you didn't compromise safety/comfort too much in the process.

Upright safety? it's possible to put bars on the sides of an upright bike, but it's very rare that the rider stays planted on the bike in the event of a crash, unlike the recumbent bike, so those bars may not help. The high center of gravity is a big negative here. Based on my previous upright bike crashes, i think a helmet and body armor would be the most helpful.

As for this point:

• Harnesses free energy to sometimes improve the efficiency of a bicycle.

I can't help you..

 

[Chalo]

It improves safety by reducing the distance you fall. This bike uses the handlebar as a crush zone in the event of a tipover, so it will eat up gravity on the way down too. I have since fitted some bars to the side that would take even more impact.

In my observation, any improvement in crash safety from recumbents is more than offset by the increased likelihood of catastrophic crashes because if their impaired handling qualities, reduced visibility, and less rider familiarity due to impracticality and liveabiliity issues. I don't personally know anyone who was killed on an upright. (Naturally, the number of people I know who ride uprights is at least 100x the number I know who ride 'bents.) I live with the remnants of a 'bent left over after the owner was killed in a crash. And I know multiple people who died early because they drove cars instead of riding or walking for transportation.

 

[neptronix]

My experience with riding them over the last few years is basically the opposite of that.
Great visibility on mine, people really take notice.
Feels more certain, handling wise, than any upright i've ever owned. And i've owned a long cargo bike. Yes, you need a few days to acclimate... but you also have to do that with your first upright bike.

Have you ever ridden a semi recumbent bike or is your opinion entirely/mostly informed by a single person's unfortunate experience?

 

[gromike]

Known quite a few who died on uprights .

 

[Chalo]

Have you ever ridden a semi recumbent bike or is your opinion entirely/mostly informed by a single person's unfortunate experience?

The only bike I ever rode that I was convinced wanted me dead was a BikeE. Venomous piece of total crap. I rented it as transportation for a long weekend with high hopes, but was embittered long before the weekend was over.

I've tried some others, none quite so bad, but none nearly as benign as the worst uprights I've ever tried.

Edit:
I rehabbed a Rans Fusion freaky sorta-recumbent bike that actually rode pretty well. It had some of the other recumbent drawbacks re walking, stashing and the like, but it rode okay. It looked like a mistake, but it was sort of the Electra Townie to the Electra Townie.

It's still for sale at the community bike shop where I work, because nobody wants it. But it rides okay.

 

[Chalo]

Known quite a few who died on uprights .

I've heard about many locals in that category, none who were personal acquaintances. All either murdered by car drivers or self-murdered while riding for "sport".

 

[neptronix]

The only bike I ever rode that I was convinced wanted me dead was a BikeE. Venomous piece of total crap. I rented it as transportation for a long weekend with high hopes, but was embittered long before the weekend was over.

I've tried some others, none quite so bad, but none nearly as benign as the worst uprights I've ever tried.

The stock handlebars on the bikeE were total crap & didn't allow you to produce enough leverage to easily keep the front wheel steady. Add wide handlebars and this improves massively - it now doesn't get skittish until you get up to 30mph. On stock handlebars, it's skittish all the time and i found that crossing over into unpleasant/dangerous territory.

I would also be sour on them if that was my only experience.

The opposite end of semi recumbent handling is the Cannondale Bent. Handling is exceptional. it's a bit more unwieldy than the bike E up to 6mph ( longer wheelbase is responsible for this ), then it gets progressively better planted and predictable, the faster you go. I've gone down super curvy mountains in excess of 40mph and it felt more confident than 2 really decked out downhill bikes going down the same mountain. Also, EXTREMELY forgiving about steering errors.. more so than any bike i've ridden.

The Maxarya i have today is right in the middle of the two. It's particularly tall for a semi recumbent bike and the handling, i'd consider good enough. I haven't tested it's limits yet because it doesn't inspire confidence.

It's kind the same situation with uprights. Some pedal bikes can start feeling sketchy at 20mph. Others, like downhill bikes, don't start to feel sketchy until you hit 40-50mph... yet somehow don't feel wobbly at low speeds either.. like they have some kind of magic geometry that's superior to everything else out there.

 

[Logic11]

The stock handlebars on the bikeE were total crap & didn't allow you to produce enough leverage to easily keep the front wheel steady. Add wide handlebars and this improves massively - it now doesn't get skittish until you get up to 30mph. On stock handlebars, it's skittish all the time and i found that crossing over into unpleasant/dangerous territory.

I would also be sour on them if that was my only experience.

The opposite end of semi recumbent handling is the Cannondale Bent. Handling is exceptional. it's a bit more unwieldy than the bike E up to 6mph ( longer wheelbase is responsible for this ), then it gets progressively better planted and predictable, the faster you go. I've gone down super curvy mountains in excess of 40mph and it felt more confident than 2 really decked out downhill bikes going down the same mountain. Also, EXTREMELY forgiving about steering errors.. more so than any bike i've ridden.

The Maxarya i have today is right in the middle of the two. It's particularly tall for a semi recumbent bike and the handling, i'd consider good enough. I haven't tested it's limits yet because it doesn't inspire confidence.

It's kind the same situation with uprights. Some pedal bikes can start feeling sketchy at 20mph. Others, like downhill bikes, don't start to feel sketchy until you hit 40-50mph... yet somehow don't feel wobbly at low speeds either.. like they have some kind of magic geometry that's superior to everything else out there.

Handling suggestion:

1st: NB that at speed the angle through which you turn the front wheel is small.
It's only at slow (feet down) speeds that you actually use the large angles.

Then look at Oval crank-sets. (Actually Elliptical)
NB that when the ellipse is big relative to the rear sprocket; it turns the rear sprocket though more degrees per degree turned by the oval sprocket.
When the ellipse is small relative to the rear sprocket; it turns the rear sprocket though less degrees per degree turned by the oval sprocket.
But the chain length DOES NOT change..!

So
lets say you set up a chain drive between your handle bars and the front goosneck, but put a highly elliptical sprocket on the handlebar side, with the ellipse at it's smallest for when the front wheel is pointing straight ahead.

Now you have:
Turn the bars many degrees for a small change in the front wheels angle from 'straight',
but
a large change in the front wheel's angle if the front wheel is at the large angles used at low speed...

ie: You now have 'variable speed steering' with low 'twitchyness' at the angles used at high speeds, but keep the ability of having the big angles that are used at low speeds...

How elliptical one of sprockets needs to be is a matter of experiment.

Also NB that you now get to actually turn your handlebars, rather than the clumsy push them off center to the right or left....

(The world would be a better place if people didn't 'own' other people's ideas: What are the chances of further idea sharing when that shit happens?)

 

[Logic11]

Even less because to one degree or another, they "draft" each other. Also, the spokes at the top of the wheel mare the only ones of note, because the front and rear ones are end-on to airflow, and the bottom ones slow to near zero ground speed at their outer extents.

I think it's a clear indictment of gimmicky aero spokes that these days, they almost inevitably occur on plastic bikes with gigantic bloated frame tubes that cancel out any spoke-related drag reduction by multiple orders of magnitude.

Yes they do and if I remember the research paper correctly; at above 18 spokes per rim; more spokes actually doesn't increase drag. There may even have been a small decrease.
Wheres that paper....
Ah!

https://www.sciencedirect.com/science/article/pii/S0167610519305884

The paper also says the wheels account for around 10% of the drag when the wind is head on and that that number increases quite dramatically when there's a crosswind.

Is the gimmicky idea worth anything?
I don't know... or care much...
It does 3 good things, easily and practically, making it 'clever' and that makes it worth sharing IMHO.
Perhaps some student, looking for thesis subject might see this.

NB
That it's not just spokes that could benefit from this Weathercocking Sprung 'Wing' idea:
Any round part of the bicycle frame that's more or less vertical would get the same effects from this treatment.

That should make it interesting to the Sun Trip race competitors, with their high up Solar panels blowing them over in crosswinds.

If you know any point them here.

 

[Logic11]

...For an upright bike, it's hard to improve the aerodynamics without making it vulnerable to cross winds...

Exactly!
This is the ONLY idea that DOES!
(a bit)

As for this point:

• Harnesses free energy to sometimes improve the efficiency of a bicycle.

I can't help you..

ye...

A 40 cm diameter wind turbine had a rated power output of 1 W and could produce power output up to 2.2 W at wind speeds of 5.5 m/s. (9m/s is the global average)

https://www.sciencedirect.com/science/article/abs/pii/S0167610513000366

That's around a whole 7 watts from 2 62 cm wheels in a 2km/h crosswind!
But hey; if its there for the taking...

Edit:
Actually its more. I remembered that a doubling of turbine diameter = a quadrupling of power.

For a 60 cm wheel X2, in a 9 m/s (global averge) wind you get a whole 268 watts!

Wind Turbine Calculator

The wind turbine calculator finds the power output, efficiency, RPM, torque, and revenue of a wind turbine (either HAVT or VAWT).

www.omnicalculator.com

Now thats heading into small E-bike motor territory!!

 

[PaPaSteve]

The only bike I ever rode that I was convinced wanted me dead was a BikeE. Venomous piece of total crap. I rented it as transportation for a long weekend with high hopes, but was embittered long before the weekend was over.

I've tried some others, none quite so bad, but none nearly as benign as the worst uprights I've ever tried.

Edit:
I rehabbed a Rans Fusion freaky sorta-recumbent bike that actually rode pretty well. It had some of the other recumbent drawbacks re walking, stashing and the like, but it rode okay. It looked like a mistake, but it was sort of the Electra Townie to the Electra Townie.

It's still for sale at the community bike shop where I work, because nobody wants it. But it rides okay.

Some people are more gifted then others.
1989, a Bay Area TV station asked me to show up with my recumbent streamliner at the local velodrome for a "Sports 2000" magazine feature.
The pro rider they brought to film couldn't go 20 feet before falling over.
A different pro rider who never rode a recumbent happened to be there saw the struggle and asked to give it a try.
He was able to do a "track stand" right from the start and then went out to do blistering speeds around the track.
Two pro riders, vastly different results.
Don't blame the bike.

 

[Chalo]

Two pro riders, vastly different results.
Don't blame the bike.

And yet anybody, pro or not, can ride competently on the first try if it's a regular bike. No vastly different results there.

I made an experimental bike that instead of a fork, had a roughly 2' rod pointing down to a 3' wide axle mounted on a tilting pivot, with a 20" nylon mag wheel at each end. Most expert riders had a great deal of trouble with it at first, while some inexperienced noobs could ride it pretty well right from the start. So I understand "don't blame the bike", but what you're leaving out is that some bikes are simply effed-up, and whether you can or can't ride them well doesn't change that.

I have yet to meet a 'bent bike that wasn't an effed-up thing to ride, even if ridden well. Some way more than others, of course. When/if I get sufficiently busted that I need one, I think it will have to be a trike so I don't break an elderly hip trying to tame a two wheeled 'bent.