aerodynamics.

themekon

A question for the scientific amongst you lot. Apologies if this has been asked before. Here goes. It goes without saying that reducing your frontal area and being as aerodynamic as you can will help in fighting the battle of wind resistance. Now, if you have a raging tail wind at your back does that still apply or are you better off making yourself as sail like as you can.
That should get you thinking.

dynamicbrick

I live on the coast, and part of my route includes 2 miles along the harbour wall into the face of a howling westerly, then turn at the end and back again.

Depending on the speed of the tail wind, and clothing worn, it doesn't really make much difference whether you sit up or not - mainly because there's very little assistance from a tail wind. The huge advantage is that you're not pedalling against the wind - which is 90% of effort with cycling on the flat.

37mph is the most I've managed on the flat with a 50mph wind to my back - I just ran out of gears and cadence... (not to mention I was shattered from the 2 miles into the headwind to get to that point).

bernithebiker

I think you can probably develop a formula for this.

Because at 1mph, with a 30mph wind on you back, you would want to be as sail like as possible.

As your speed increases, the relative speed of the tailwind decreases, so there will come a point where you will want to get aero again. It would be nice and simple if that 'tipping point' speed were 30mph, but I suspect it isn't that simple....

Any aeronautical engineers out there?

cougie

I remember reading a bike book that mentioned that Scandinavian riders would fashion some kind of sail to take advantage of a tail wind. I've never seen any proof of this though - it may be a myth.

FlacVest

bernithebiker wrote:

I think you can probably develop a formula for this.

Because at 1mph, with a 30mph wind on you back, you would want to be as sail like as possible.

As your speed increases, the relative speed of the tailwind decreases, so there will come a point where you will want to get aero again. It would be nice and simple if that 'tipping point' speed were 30mph, but I suspect it isn't that simple....

Any aeronautical engineers out there?

This. It's as simple as applying some common sense to what's happening around you.

If the headwind is helping you, it will only help UNTIL you overcome that speed of its movement and again start moving faster than it.

It doesn't help a car much if you have a 10 mph tail wind if you're going 80 mph does it? Slightly, but you're still hitting air particles in front of you.

Same on a bike, but at lower speeds. If you have a 10 mph tail wind, you'll be able to feel when you start fighting it. My helmet is loud, and I can gauge the wind speed depending on what I hear. I know I have a tail wind when I can actually hear the tires on the pavement. Normally, with no wind, I can't hear that at 20 mph.

So you could sit up and ride the hoods until you out pace the wind... but that's going to be an extra 20 or so mph on top of what you're doing. The the tailwind at 10mph is giving you a virtual 10 mph of free, frictionless speed you can use.

Obviously there is more math involved to make this not as simple as I state it, but the gist is what's important here.

simona75

themekon wrote:

A question for the scientific amongst you lot. Apologies if this has been asked before. Here goes. It goes without saying that reducing your frontal area and being as aerodynamic as you can will help in fighting the battle of wind resistance. Now, if you have a raging tail wind at your back does that still apply or are you better off making yourself as sail like as you can.
That should get you thinking.

If you really are The Mekon you should really be able to work this out yourself

declan1

dynamicbrick wrote:

I live on the coast, and part of my route includes 2 miles along the harbour wall into the face of a howling westerly, then turn at the end and back again.

Depending on the speed of the tail wind, and clothing worn, it doesn't really make much difference whether you sit up or not - mainly because there's very little assistance from a tail wind. The huge advantage is that you're not pedalling against the wind - which is 90% of effort with cycling on the flat.

37mph is the most I've managed on the flat with a 50mph wind to my back - I just ran out of gears and cadence... (not to mention I was shattered from the 2 miles into the headwind to get to that point).

You sound about as aerodynamic as a brick :P

themekon

simona75 wrote:

themekon wrote:

A question for the scientific amongst you lot. Apologies if this has been asked before. Here goes. It goes without saying that reducing your frontal area and being as aerodynamic as you can will help in fighting the battle of wind resistance. Now, if you have a raging tail wind at your back does that still apply or are you better off making yourself as sail like as you can.
That should get you thinking.

If you really are The Mekon you should really be able to work this out yourself

Too busy sorting out Dan Dare

nolight

themekon wrote:

Now, if you have a raging tail wind at your back does that still apply or are you better off making yourself as sail like as you can.
That should get you thinking.

A sail is useless if you are on a power boat.

bernithebiker

nolight wrote:

themekon wrote:

Now, if you have a raging tail wind at your back does that still apply or are you better off making yourself as sail like as you can.
That should get you thinking.

A sail is useless if you are on a power boat.

....unless the engine's broken down......

it's all speed dependent. If you were pootling along at 8 knots, and had a 20 knot tailwind, then a sail would be helpful.