Lean angle vs G-force

[Cruisin' Craig]

O.K then. I've now looked at several sites that do the calculation in a couple of different ways, and I grumpily concede defeat.

[FROSTY:Me]

WHERE is the box that says --I lean far enough to get round the bloody corner

[Mikkel]

That's exactly right! Now they stand there for days 'discussing' how they fucked up so bad.
I have worked with mullet haired, jail tatt'd, toothless, chain smoking, compulsive cursing machine operators who make more sense and end up correcting the balls up's thier 'superior' Engineer supervisors create...
Now they argue about lean angles and come up with seemingly infinte reasons why they cannot agree.
Dont get me started on 'mechanical engineers'...

Well, cock-ups happen. But on the other hand I'd like to see Joe average try and design a two kilometer long bridge or tunnel, built/dug from each end and have them meet up at the middle.

Truth be told they get it right almost every time.

Also true that an engineer who doesn't listen to the guy who's going to do the work is a fool beyond hope. Planning is one thing - execution another.

However, look for a second at what the planning, design and knowledge that is engineering has made us capable of. How'd you like to catch a ferry to cross Auckland harbour - oh, forget that, the ferry is engineered as well. How about having to slosh through your own and everybody elses shit because no one ever thought about a sanitation network... No, be happy that there are people out there who does the civil engineering bits.

And sure, these days budgeting is atrocious. However, I wouldn't blame the civil engineers. They are most likely told by someone further up the ladder (no Dan, not that ladder) that we want to build a bridge here or there and it can't cost more than this or that - make it happen or look for another job.
Oh the examples of creative budgeting and planning I could relate... Usually it's the bloody bureacrats who instigate it.

[madandy]

Ya took a while

[avgas]

You can have acceleration change the direction of the velocity vector - but not the magnitude - thus maintaining a constant speed.

So acceleration doesn't change the magnitude of speed? May i ask what does You are partially right - but you must see the joke i have here.

[Mikkel]

Ya took a while

Always happy to bite.

So acceleration doesn't change the magnitude of speed? May i ask what does You are partially right - but you must see the joke i have here.

I think I see what you mean. Speed being a scalar hasn't got a magnitude - only a value. That value being the magnitude of the velocity...

Edit: A joke people taking an interest in this thread might appreciate: http://www.xkcd.com/123/

[avgas]

I think I see what you mean. Speed being a scalar hasn't got a magnitude - only a value. That value being the magnitude of the velocity...

Don't forget while speed may be considered a scalar, integration/diff brings you back and forth between Acceleration/Speed/Distance with respect to time.
While for theory's sake you could say that time is nothing. This actually brings all components to zero.
Likewise if no distance is covered it than is there an acceleration?
If there is no acceleration? is there force?
Which brings me to case and point of the joke, without knowing the distance covered over a period of time (i.e. the speed) or considering this constant (easiest is to consider 1 - as multiples of 1 do not affect equations) what angle do you feel 0.5G.
Well i think if you were to lean around 45 degrees you may feel that - because at that point it would be your leg hold half the weight of bike off the road
Now do you see the joke, its nothing to do with the angle more the speed and the corner distance. The angle helps you compensate for the G force. Motards/Sidecars dont lean do they - they slide. Do they experience 0G?

[Badjelly]

You certainly like to make things complicated, don't you avgas?

[avgas]

You certainly like to make things complicated, don't you avgas?

The only simply G force is the one you feel on the earths surface. And even that one seems to f people up from time to time. But yes your are correct calculating G-Forces on a bike is like deriving a PID controller for a Space shuttles pitch.

[Mikkel]

Don't forget while speed may be considered a scalar, integration/diff brings you back and forth between Acceleration/Speed/Distance with respect to time.
While for theory's sake you could say that time is nothing. This actually brings all components to zero.
Likewise if no distance is covered it than is there an acceleration?
If there is no acceleration? is there force?
Which brings me to case and point of the joke, without knowing the distance covered over a period of time (i.e. the speed) or considering this constant (easiest is to consider 1 - as multiples of 1 do not affect equations) what angle do you feel 0.5G.
Well i think if you were to lean around 45 degrees you may feel that - because at that point it would be your leg hold half the weight of bike off the road
Now do you see the joke, its nothing to do with the angle more the speed and the corner distance. The angle helps you compensate for the G force. Motards/Sidecars dont lean do they - they slide. Do they experience 0G?

Nope - I'm just very very confused now.

[avgas]

Nope - I'm just very very confused now.

Ok ok, i'm getting ahead of myself a bit mabey.
Go out on the bike, do a constant 1kph round a corner at 26 degree lean angle. How many g do you feel?
Now do the same corner at 100kph round a corner at 26....? how many g do you feel?
Now go out at 0kph in the same experiment? at what angle to do experience 0.5G?

[cooneyr]

Ok ok, i'm getting ahead of myself a bit mabey.
Go out on the bike, do a constant 1kph round a corner at 26 degree lean angle. How many g do you feel?
Now do the same corner at 100kph round a corner at 26....? how many g do you feel?
Now go out at 0kph in the same experiment? at what angle to do experience 0.5G?

Yerbut - that wasnt the question, your starting at the wrong point. There is defiantly a speed and radius component required to achieve a 0.5G horizontal acceleration. The point of this question though is assuming you are pulling 0.5G (at whatever speed that takes on a given radius) how much would be leaning. The lean angle doesnt change for a a given horizontal acceleration.

If you vary the speed for a given radius the horizontal acceleration changes or if you vary the radius for a given speed the horizontal acceleration changes.

Coming back to your side car point. The side car doesnt lean (well it does a little bit) but the angle of the resultant vector (result of 0.5G horizontal and 1G vertical) is still at 26.5 degrees. For a two wheeled motorbike it must lean else the horizontal acceleration makes you end up on your arse.

Cheers R

[Mikkel]

Ok ok, i'm getting ahead of myself a bit mabey.
Go out on the bike, do a constant 1kph round a corner at 26 degree lean angle. How many g do you feel?
Now do the same corner at 100kph round a corner at 26....? how many g do you feel?
Now go out at 0kph in the same experiment? at what angle to do experience 0.5G?

cooneyr did a good job.
One thing that's worth mentioning though is that it's not the lean angle of the bike - it's the lean angle of the centre of mass. I.e. what is the angle between vertical and the vector that goes from the contact patch through the centre of mass. Which is why you can corner sharper by hanging off.
Obviously you can't do that in a car - the result here is that there's more force on the outside wheels than the inside to reflect this. This is one of the main reasons for desiring a centre of mass as low to the ground as possible in cars since the higher up it is - the bigger the difference between inside and outside wheels.

However, I do believe most of this was covered earlier in the thread.