MotoGP 2013

[roogazza]

Doubt that's the problem. GP engines have been running in reverse for a long time. The Yamaha he rode did.

Yes, Edwards has been around a long time. I 've always thought forward rotating cranks were to aid corner entry, rather than exit ?
Maybe someone can explain this further ?

[Mental Trousers]

Doubt that's the problem. GP engines have been running in reverse for a long time. The Yamaha he rode did.

Probably right. That bike seems to be either a rocket or a bucket of shit. Some tracks Colin has kicked the Aprilia's arses, but most of them it looks terrible.

Yes, Edwards has been around a long time. I 've always thought forward rotating cranks were to aid corner entry, rather than exit ?
Maybe someone can explain this further ?

With most bikes that have the engine across the frame the crank rotates forward. When you throttle off it causes the bike to act a bit like you're dragging the rear brake a little, pulling you into the corner.

If the crank is rotating backwards you don't get that. Instead when you accelerate it's like you're dragging the rear brake a bit, keeping the bike from doing wheelies.

[DidJit]

Hey Didjit can I just say thanks very much for always posting interesting articles to do with MotoGP, I don't frequent those sites so I guess I pretty much rely on your posts to get all the gossip. So I really appreciate it, cheers.

You're welcome, mate. I spend all day in front of a computer, so I'm always keeping an eye on what comes up. Quite a few of the other guys do the same though — share their finds. Sharing is caring.

... Viñales however has that ever-sought after "freak" ability, ...

Wait til Alex Marquez gets in the paddock — even faster than his big brother by some accounts...

Check this out: Inspire. This is LCR Honda’s publication that they put out for their sponsors to keep them in the loop of what’s happening with their team and in MotoGP in general. Impressive!

[pritch]

Yes, Edwards has been around a long time. I 've always thought forward rotating cranks were to aid corner entry, rather than exit ?

That's what I understood. Wheels, engine, gearbox all rotating in the same direction make the bike resist any change in direction. The alternative to running the engine backwards is ever steeper steering angles which results in stability problems at speed. Kawasaki may be able to confirm that?

It,s just possible I have all that in writing here somewhere but I need an early night.

[Mental Trousers]

Spinning mass resists change irrelevant of the direction of rotation. The direction it's rotating does govern the affect that resisting change has on the bike though.

[bogan]

Spinning mass resists change irrelevant of the direction of rotation. The direction it's rotating does govern the affect that resisting change has on the bike though.

Your two sentences contradict each other, the second being correct. Things spinning the other way cause the opposite reaction force, thus lowering the resistance to a change of direction.

[pritch]

Things spinning the other way cause the opposite reaction force, thus lowering the resistance to a change of direction.

Thassit - in a nutshell.

I had a look this morning, Kevin Cameron discusses the 2004/5 M1 design in considerable detail. Almost every concievable detail - except the one I was after apparently?

[Mental Trousers]

Spinning mass resists change irrelevant of the direction of rotation. The direction it's rotating does govern the affect that resisting change has on the bike though.

Your two sentences contradict each other, the second being correct. Things spinning the other way cause the opposite reaction force, thus lowering the resistance to a change of direction.

Nah they don't. A spinning mass resists change from any direction.

Try and move the axis it's spinning on and it'll resist. But the reaction will be at 90 degrees to the direction you try to move it in (counter steering on a bike for instance)

Slowing a spinning mass is force -> opposite reaction.

[bogan]

Nah they don't. A spinning mass resists change from any direction.

Try and move the axis it's spinning on and it'll resist. But the reaction will be at 90 degrees to the direction you try to move it in (counter steering on a bike for instance)

Slowing a spinning mass is force -> opposite reaction.

For a single one yes, but when you add a second spinning mass going the opposite way in the same frame, it'll reduce the reaction force, therefore, the resistance to change also reduces.

[DidJit]

You learn something new everyday.

You really do.

[tbs]

Yamaha use a counter rotating crankshaft because it is impossible to pin the mighty cheese.

You read that correctly.....



Motorbikes have three big gyroscopes acting on them, and under normal circumstances they all turn the same direction. You have your wheels at either end, and you have your crankshaft right in the middle of the bike, and up quite high. If you watched the mighty cheese, then you will understand just how difficult it is to lean a gyroscope over, and the faster it is spinning, the harder it is to budge. Now imagine an 8kg gyroscope spinning at upwards of 10,000 rpm in the middle of your bike, and two more touching the ground, and you should have a pretty damn good idea of just how hard it is to make a speeding motorbike lean over.... and as we all know, leaning is how you turn.

Then it gets more complicated, as the further the ends of your crankshaft are from the centre line of the bike, the further they have to move off their preferred plain of rotation. The angle of lean is the same, but the longer the gyro you are trying to tilt, the further the ends have to go, and the more physically difficult it is to move.

So: While other companies use variations on the V4 to power their GP bikes, which are nice and narrow. Yamaha chose to go with an across the frame inline 4. This has a number of advantages. Mainly it leaves lots of room for the air intake, fuel tank location, and fuel injectors, and allows Yamaha to move the engine around in the bike to optimize weight distribution, but it has one big disadvantage. Namely, that long gyroscope spinning in the middle of the bike resisting any efforts to lean the bike over.

So, by reversing the rotation of the crankshaft, Yamaha were able to offset the gyroscopic force generated by the wheels, meaning that it has much less overall gyroscopic force acting on it, so the bike is much easier to lean over. It does mean some extra gearing which robs power, so bikes like the Honda do tend to be faster in a straight line, but the Yamaha makes up for it all in the corners, especially corner entry.

I have a theory that finesse riders like Rossi and Lorenzo are naturally suited to the Yamaha, while riders like Stoner are comfortable manhandling the harder to turn Honda or Ducati and then using the power to get out of the corner hard and charge the straights. I don't think Rossi was ever going to have the goods to throw the Ducati around quite how it needs to be. He'll be a new man again on the Yamaha, which let's face it, has only got better in the last two years.

The counter rotating crank has some other effects on brake dive and wheelie, but I can't quite remember them at the moment.

Oh, and I don't think the crank was the source of Colin's woes this year, because it should have made the bike easier to turn.... not harder.

[roogazza]

Yamaha use a counter rotating crankshaft because it is impossible to pin the mighty cheese.
You read that correctly.....
Motorbikes have three big gyroscopes acting on them, and under normal circumstances they all turn the same direction. You have your wheels at either end, and you have your crankshaft right in the middle of the bike, and up quite high. If you watched the mighty cheese, then you will understand just how difficult it is to lean a gyroscope over, and the faster it is spinning, the harder it is to budge. Now imagine an 8kg gyroscope spinning at upwards of 10,000 rpm in the middle of your bike, and two more touching the ground, and you should have a pretty damn good idea of just how hard it is to make a speeding motorbike lean over.... and as we all know, leaning is how you turn.

Then it gets more complicated, as the further the ends of your crankshaft are from the centre line of the bike, the further they have to move off their preferred plain of rotation. The angle of lean is the same, but the longer the gyro you are trying to tilt, the further the ends have to go, and the more physically difficult it is to move.

So: While other companies use variations on the V4 to power their GP bikes, which are nice and narrow. Yamaha chose to go with an across the frame inline 4. This has a number of advantages. Mainly it leaves lots of room for the air intake, fuel tank location, and fuel injectors, and allows Yamaha to move the engine around in the bike to optimize weight distribution, but it has one big disadvantage. Namely, that long gyroscope spinning in the middle of the bike resisting any efforts to lean the bike over.

So, by reversing the rotation of the crankshaft, Yamaha were able to offset the gyroscopic force generated by the wheels, meaning that it has much less overall gyroscopic force acting on it, so the bike is much easier to lean over. It does mean some extra gearing which robs power, so bikes like the Honda do tend to be faster in a straight line, but the Yamaha makes up for it all in the corners, especially corner entry.

I have a theory that finesse riders like Rossi and Lorenzo are naturally suited to the Yamaha, while riders like Stoner are comfortable manhandling the harder to turn Honda or Ducati and then using the power to get out of the corner hard and charge the straights. I don't think Rossi was ever going to have the goods to throw the Ducati around quite how it needs to be. He'll be a new man again on the Yamaha, which let's face it, has only got better in the last two years.

The counter rotating crank has some other effects on brake dive and wheelie, but I can't quite remember them at the moment.

Oh, and I don't think the crank was the source of Colin's woes this year, because it should have made the bike easier to turn.... not harder.

a bloody good job of explaining it all, Ta !

[Crasherfromwayback]

So, by reversing the rotation of the crankshaft, Yamaha were able to offset the gyroscopic force generated by the wheels, meaning that it has much less overall gyroscopic force acting on it, so the bike is much easier to lean over. It does mean some extra gearing which robs power, so bikes like the Honda do tend to be faster in a straight line, but the Yamaha makes up for it all in the corners, especially corner entry.
.

Think you'll find it was originally done to stop the 500 smokers wheelstanding so badly. I believe Honda got the drop on everyone else. So the story goes (well..the one I heard)...when Honda took their 500's to the Isle of Mann...the other factories watching wondered why the Honda nose dived over the jumps instead of trying to loop out. Then the penny dropped. Think the cornering assistance was an added bonus.

[eelracing]

I believe Honda got the drop on everyone else. So the story goes (well..the one I heard)...when Honda took their 500's to the Isle of Mann...the other factories watching wondered why the Honda nose dived over the jumps instead of trying to loop out. Then the penny dropped. Think the cornering assistance was an added bonus.

Sorry Crasher but you heard wrong,the original idea was about maneuverability/change of direction.
Yamaha have had reverse crank rotation since it's (and 2 strokes)very first 500cc Championship with Agostini in 75.
Honda adopted it from 87 onwards and then subsequently dropped it in the current 4 $troke era.

[Crasherfromwayback]

Sorry Crasher but you heard wrong,the original idea was about maneuverability/change of direction.
Yamaha have had reverse crank rotation since it's (and 2 strokes)very first 500cc Championship with Agostini in 75.
Honda adopted it from 87 onwards and then subsequently dropped it in the current 4 $troke era.

Odd how stories can get so fucked up over the years! Very cool to learn Yamaha started it so early too.