Sepang Test (Jan 31st - Feb 2nd 2012)

BarryMachine · Feb 4, 2012

Stoner 27 said:
Bazz whats made the most differance, tilting back the engine.. or the new Bridgestones?

I reckon both would have made a differance but the tyres would have played a big part..

Again, the problem was a "vibration" ......... tyres tend to just let go. The tyres will be important but the same for everyone. "The vibration/chattering is a Vtwin/Ltwin or inline ( longitudinally ) engine problem. Yamaha have perhaps been cleverer than we know. I believe the 90 deg is about as bad as it can get. and the further horizontal one of the cylinders the worse it gets also.

You guys really need to read up on Vibrating Structure Gyroscopes, its really quite interesting to and I believe the most base concept required to understand what the problem is. Its not STATIC its a dynamic pulsating force, the moment Casey complained about the "chattering" Ducati should have looked for a cyclic force. The moment Rossi mentioned the same thing only in the more eloquent term "the ....... vibration!" they should have realized they were ......... for ignoring Stoner.

Besides, I'm sure they would have tested it with several tyres.

Baffy · Feb 4, 2012

BarryMachine said:
Again, the problem was a "vibration" ......... tyres tend to just let go. The tyres will be important but the same for everyone. "The vibration/chattering is a Vtwin/Ltwin or inline ( longitudinally ) engine problem. Yamaha have perhaps been cleverer than we know. I believe the 90 deg is about as bad as it can get. and the further horizontal one of the cylinders the worse it gets also.

Besides, I'm sure they would have tested it with several tyres.

You seem to know your .... barry, but can you explain the correlation between a "vibration" and the front letting go? in lamens terms not an essay

You always relate a solution back to dirt tracking, but all of the non oil based dirt tracks I have ridden on tyre pressure has more to do with not losing the front than riding style.

J4rn0 · Feb 4, 2012

birdman said:
Remember overnight specials. They were developed overnight! Remember that shakedown test Ducati had to have with Checa. Data for Loris to rush back to bridgestone for their specially developed experiment.

IF helping Rossi is their (Bridgestone's) hidden intention, and IF they can churn out special tires overnight, THEN they must have been really distracted during the entire 2011 season...

Conspiracy theorists are always short sighted, and it is certainly not a coincidence...

Casey Stoner, by the way, said that it is the extra kilos added to the bikes this year that may be causing the chattering problems they are experiencing. He said they must now find the perfect balance again.

BarryMachine · Feb 4, 2012

Baffy said:
You seem to know your .... barry, but can you explain the correlation between a "vibration" and the front letting go? in lamens terms not an essay

You always relate a solution back to dirt tracking, but all of the non oil based dirt tracks I have ridden on tyre pressure has more to do with not losing the front than riding style.

Ok I'll try again.

When cornering A bike has a balance point where the grip at both tyres is in balance. It is probably around the current centroid of the whole bike, which is dependent on many thing eg rider posn. Fuel mass corner slope etc. etc. etc. ( but all fairly STATIC factors )

In the L90 engine a VSG is set up between the two cylinder banks.

A VSG: from Wiki : "The underlying physical principle is that a vibrating object tends to continue vibrating in the same plane as its support rotates. In the engineering literature, this type of device is also known as a Coriolis vibratory gyro because as the plane of oscillation is rotated, the response detected by the transducer results from the Coriolis term in its equations of motion ("Coriolis force"). "

With the front cylinder way out in front like it was with the Duc. We get a pulsating VSG force ( pulsating as the 4 cylinders are always moving in relation to each other ....... its not constant, ), and the force is closer to the front as the cylinder is way out front and huge because that cylinders action is way away from the centroid of the bike. This gyroscopic force in acting longitudinal to the bike ( same plane as the support rotates ). As with any gyro scope, they do not like to yaw. So the bike would not want to go round the corner, But since this gyroscopic force is pulsating, so to is the effect on grip. Ergo the front would experience a pulsating extra force trying to stop it turning.

On your tyre pressure thing ......... Yes if you run with flat tyres it will feel .... if you run with tyres too hard it will feel .....

mate! Ducati ( as I assume everyone does ) would have set up their bike perfectly at times and it still happened. Bit of a moot point really ....... yes you have to set up your bike right.

If you don't think gyroscopes can pulsate ....... think of the balance wheel in a clock or watch ( old mechanical ones i mean ) then remember the action of 4 pistons is far more complicated.

Baffy · Feb 4, 2012

BarryMachine said:
Ok I'll try again.

When cornering A bike has a balance point where the grip at both tyres is in balance. It is probably around the current centroid of the whole bike, which is dependent on many thing eg rider posn. Fuel mass corner slope etc. etc. etc. ( but all fairly STATIC factors )

In the L90 engine a VSG is set up between the two cylinder banks.

A VSG: from Wiki : "The underlying physical principle is that a vibrating object tends to continue vibrating in the same plane as its support rotates. In the engineering literature, this type of device is also known as a Coriolis vibratory gyro because as the plane of oscillation is rotated, the response detected by the transducer results from the Coriolis term in its equations of motion ("Coriolis force"). "

With the front cylinder way out in front like it was with the Duc. We get a pulsating VSG force ( pulsating as the 4 cylinders are always moving in relation to each other ....... its not constant, ), and the force is closer to the front as the cylinder is way out front and huge because that cylinders action is way away from the centroid of the bike. This gyroscopic force in acting longitudinal to the bike ( same plane as the support rotates ). As with any gyro scope, they do not like to yaw. So the bike would not want to go round the corner, But since this gyroscopic force is pulsating, so to is the effect on grip. Ergo the front would experience a pulsating extra force trying to stop it turning.

On your tyre pressure thing ......... Yes if you run with flat tyres it will feel .... if you run with tyres too hard it will feel .....

mate! Ducati ( as I assume everyone does ) would have set up their bike perfectly at times and it still happened. Bit of a moot point really ....... yes you have to set up your bike right.

If you don't think gyroscopes can pulsate ....... think of the balance wheel in a clock or watch ( old mechanical ones i mean ) then remember the action of 4 pistons is far more complicated.

Here is where i don't follow you, an engine does not change its firing order, rotational direction when it feels like it. Any "vibration" caused by the engine is going to be a 'static' variable so if it was really the problem, I would have thought at least one engineer would have found a way to counter it?

As far as tyres go, you missed my point. On a regular sand / soft soil based track, running a harder PSI will help even the newest rider more than how they enter the corner. But despite that you profess that stoners ability to slide the bike neutralises the "vibration" correct?

P.S I'm too lazy to read all of your replies in other threads

P.P.S Go to bed its 12:30 dow there where you try and make your day longer.

BarryMachine · Feb 4, 2012

Baffy said:
But despite that you profess that stoners ability to slide the bike neutralises the "vibration" correct?

Not neutralises it, but lessens its affect. Gyroscopes fight yaw, but not sideways movement, so by sliding the bike Stoner both put the usual grip emphasis back on the front, and got the bike pointed round the corner by shifting this "gyro" sideways around the front tyre.

DaddiiKong · Feb 4, 2012

Barry- Wouldn't his ability to steer with the back also help by using the added leverage of the rest of the bike (which is so far away from the vibration) to overcome the gyroscopic effect to get the bike turned?

I.e.- Steering with the front = trying to steer with the front = steering forces close to the gyroscopic vibration effect= harder to overcome issues

steering with the rear = sliding back of bike= steering forces further from gyroscopic vibration effect = easier to overcome issues.

edit just read your post above mine, and I think that's pretty much what you were saying

Jumkie · Feb 4, 2012

Baffy said:
wait... WAIT!

I thought jumkie was a tequila swigging wet back?

Jumkie · Feb 4, 2012

J4rn0 said:
IF helping Rossi is their (Bridgestone's) hidden intention, and IF they can churn out special tires overnight, THEN they must have been really distracted during the entire 2011 season...

Conspiracy theorists are always short sighted, and it is certainly not a coincidence...

Casey Stoner, by the way, said that it is the extra kilos added to the bikes this year that may be causing the chattering problems they are experiencing. He said they must now find the perfect balance again.

Wait wait, am i really agreeing with u?

(neo-bobs mite b rite, mayb i am losin my mind)

J4rn0 · Feb 4, 2012

Jumkie said:
Wait wait, am i really agreeing with u?

(neo-bobs mite b rite, mayb i am losin my mind)

I think you are finding your normal mind again. Now that Rossi has been in purgatory for so long (and it is rather neo-boppers who have become obnoxious), you can afford being more objective in matters re. Valentino.

J4rn0 · Feb 4, 2012

gui22a · Feb 4, 2012

WTF Ducati has done to the engine?

Hecotr Barbera's statement:

He also found the engine output to be similar to that of the competition:

"I was near some Yamahas out on track, and we were right with them under acceleration until fourth gear. They had a little something more in the higher gears, but it wasn't much. (...)

It seems they've lost engine performance compared to the weakest engine in paddock. Could it be? They need to rework it for Qatar, it will be very important there.

birdman · Feb 4, 2012

J4rn0 said:
IF helping Rossi is their (Bridgestone's) hidden intention, and IF they can churn out special tires overnight, THEN they must have been really distracted during the entire 2011 season...

Conspiracy theorists are always short sighted, and it is certainly not a coincidence...

Casey Stoner, by the way, said that it is the extra kilos added to the bikes this year that may be causing the chattering problems they are experiencing. He said they must now find the perfect balance again.

The overnight thing was just to say bridgestone had time to develop the special experimental front after Checa tested the Ducati and publicly criticized the tires. When the SBK champion says in public your product is .... it is likely to have some effect.

But I think it's mostly Ezpeleta that is trying everything to avoid another boring snoozefest like 2011. They need higher ratings, that's how they make money apparently. What's the best way to get more entertainment and higher ratings? Get the prized cash cow Rossi at the front. I think its ok, Ducati need help anyway. But dismissing the whole thing as just a coincidence is too much.

hawkdriver · Feb 4, 2012

BarryMachine said:
Vibrational forces or resonant forces are not necessarily linear. Forget the linear relationship thing and the inversely prop. we are taking a vibrational force that pulses.

Forget F=ma ...... We are talking:

for vsg we are talking:

feel free to apply it

, or learn what it means a least.

And irrespective of the rev's the force at the front tyre only has to exceed ( by even the most minimal amount when on the edge of traction ) that force needed for traction. VSG would cause the normal force at the tyre to increase and decrease in a cyclic manner. ie. a vibration as it gripped/let go/gripped/let go etc. etc. etc. VSG would take have the effect of making the bike want to go straight when the rider is trying to go round a corner, in short the front is lost.

Ducati did shorten the bike with a CF head frame. The Al. twin spar was not done to change this as they would make the bike too unstable. What makes you think it is actually shorter? In any case this would not explain why "the ....... vibration" is gone.

I think you need to do a few years of physics or mechanics hawk, I'm not sure you are talking anywhere near the metalanguage required.

Barry you are full of .... lmao, if you can't tell the bike is shorter you are blind. They also changed Rossi's riding position and he has said himself that he can now load the front of the bike. The bike was expieirencing problems at corner entry, the engine is applying zero power while the rider is applying the brakes. They have simply put more weight on the front of the bike and changed the tank so that Rossi and the other riders could also effectivly get more weight on to the front of the bike. Rossi rides the front tire, it's his style and he needs to be able to load it.

Here it is directly from Furusawa

“Whichever the engine configuration may be, inline or V-formation, targeted weight distribution should be no different, about 50/50. It could be a fraction of that at either end, but I am not going into that,” Furusawa said. “I believe the inline engine is more advantageous when fitted within a shorter wheelbase, which is more agile. In the V-configured engine, the rear bank tends to shift the mass rearward, which must be offset by lengthening the wheelbase.”

The old Duc had an L engine that took up even more space then a V engine, and required a longer wheel base. The new Duc has a narrowed V engine which is clearly mounted more forward in the chassis and the wheel base is shorter. The bike is much closer to the Honda now. By your reasoning Duc should have just tilted the engine back and left the wheel base alone and the Yamaha which is the best handling bike on the grid should be an unstable POS.

Your fomula is .... in this application, here you go

90 degree V- 4 engine ( b[sub]1 [/sub]= 45° ; b[sub]2 [/sub]= 135° ; b[sub]3 [/sub]= 45° ; b[sub]4 [/sub]= 135° ; a[sub]1 [/sub]= 0° ; a[sub]2 [/sub]= 270° ;

a[sub]3 [/sub]= 0° ; a[sub]4 [/sub]= 270° ) , like Ducati Desmosedici GP5 Twinpulse : second order yawing

couples are balanced.

birdman · Feb 4, 2012

hawkdriver said:
By your reasoning Duc should have just tilted the engine back and left the wheel base alone and the Yamaha which is the best handling bike on the grid should be an unstable POS.

That was actually the case once:

"A half-hour later it was time to assess the challenge facing Valentino Rossi in 2004 by riding Carlos Checa's Fortuna Yamaha YZF-M1. Climbing into the saddle, the M1 felt much smaller than the other two bikes -- and felt almost 600 Supersport-like compared with the Kawasaki. On track, the M1 was much easier to change direction quickly than the others, especially in the fast esses.

Still, the bike wants to play tricks on you in corners, first feeling like it wants to tuck the front wheel as you let off the brakes and get back on the gas."

OK, the RC211V still lofts the front wheel easily exiting slower corners, but it all felt controllable as well as highly thrilling. The same was true exiting the medium-speed right-hander in the stadium, where the RC211V's long, (56.7-inch) wheelbase and ideal riding position meant I could have fun power-sliding without worrying about the front wheel making friends with the sky. Might even have left a ...... as proof, too...

There's not nearly as much weight transfer under heavy braking on the RC211V as on the Kawasaki, a reflection of its longer, lower architecture and the rider's lower positioning. The RC211V was superbly stable through the long, fast sweeper climbing the hill away from the chicane, plus it steers into corners well on the brakes.

Read more: http://www.motorcyclistonline.com/features/motor_gp_2003/index.html#ixzz1lSU3M5Rt

frizzle · Feb 4, 2012

gui22a said:
WTF Ducati has done to the engine?

Hecotr Barbera's statement:

It seems they've lost engine performance compared to the weakest engine in paddock. Could it be? They need to rework it for Qatar, it will be very important there.

It's a new formula remember (1000cc)

How do you know that Yamaha isn't now the strongest engine?

michaelm · Feb 4, 2012

hawkdriver said:
By your reasoning Duc should have just tilted the engine back and left the wheel base alone .

As far as anything I have read goes, the concensus seems to be that ducati have just tilted the L4 back, not made a narrower angle V4, although they are being secretive. Barbera is doing nearly as well on a bike without the tilting back though, so maybe it is the wheelbase and aluminium chassis which has helped, evidence against the bigbang engine theory.

I did once understand a lot of physics, alas a long time ago, but never much engineering so I will have to rely on you and barry for that part of the debate. I do remember ducati saying that they deliberately changed the balance of the 2010 bike, I am fairly sure shifting it rearwards, in the attempt to make it "more rideable' so perhaps they did exactly the wrong thing, which would be consistent with the outcome in 2010 and 2011.

gui22a · Feb 4, 2012

Frizzle said:
It's a new formula remember (1000cc)

How do you know that Yamaha isn't now the strongest engine?

[/left][/left]

Yamaha inline 4 usually have problems of overheating I think.

BarryMachine · Feb 4, 2012

hawkdriver said:
Barry you are full of .... lmao, if you can't tell the bike is shorter you are blind. Do you have figures for this? Until I see them I shall remain "blind". Are you saying an operating engine has absolutely no gyroscopic forces? Wrong, very wrong. Do you believe they have invented a gyroscopic cancelling device? if so I think Ducati should quit MGP and go onto the more importanat anti-gravity device

Get real mate.

They also changed Rossi's riding position and he has said himself that he can now load the front of the bike. The bike was expieirencing problems at corner entry, the engine is applying zero power while the rider is applying the brakes ( moot point ........ the pistons are still reciprocating ).

They have simply put more weight on the front of the bike and changed the tank ( didn't someone say the tank is now under the seat? How does that firt with your theory? NO go

) so that Rossi and the other riders could also effectivly get more weight on to the front of the bike. Rossi rides the front tire, it's his style and he needs to be able to load it.

Here it is directly from Furusawa

The old Duc had an L engine that took up even more space then a V engine, and required a longer wheel base. ( Again do you have figures for ths? Ducati tried several lengths of the old Monocoque frame ...... it did not cure the problem )

The new Duc has a narrowed V engine which is clearly mounted more forward in the chassis and the wheel base is shorter. The bike is much closer to the Honda now. By your reasoning Duc should have just tilted the engine back and left the wheel base alone and the Yamaha which is the best handling bike on the grid should be an unstable POS.

Your fomula is .... in this application, here you go

90 degree V- 4 engine ( b[sub]1 [/sub]= 45° ; b[sub]2 [/sub]= 135° ; b[sub]3 [/sub]= 45° ; b[sub]4 [/sub]= 135° ; a[sub]1 [/sub]= 0° ; a[sub]2 [/sub]= 270° ;

a[sub]3 [/sub]= 0° ; a[sub]4 [/sub]= 270° ) , like Ducati Desmosedici GP5 Twinpulse : second order yawing

WTF has this to do with anything? Is this just the degrees at one point of firing?

couples are balanced. Thinking a bit Statically there again

You say that tipping the engine back statically moves the centre of mass of the engine, which direction has the static mass moved? Are the heads heavier than the sump/gearbox?

In any case, lengthening or shortening the bike is a moot point, the failure was .......... "a ....... vibration". Not a slowness to turn or a general loss of agility, it didn't matter what length the bike is/was .......... the problem was " the ....... vibration" Get that?

You are wasting my time until you get that simple basic fact right ........ Ask yourself what was causing

"the ....... vibration"

nothing to do with static agility or stability, that testing was done ......... fail. Get over it and take it on board. That was near 6 months ago! They struck wheelbase off the list. Sure Rossi might want a shorter bike but they still had the problem. Do you think Rossi asked for only one change to the existing Duc?

xx CURVE xx · Feb 4, 2012

i like ham

Sepang Test (Jan 31st - Feb 2nd 2012)

Help Support MotoGP Forum:

BarryMachine

Baffy

J4rn0

BarryMachine

Baffy

BarryMachine

DaddiiKong

Jumkie

Jumkie

J4rn0

J4rn0

gui22a

birdman

hawkdriver

birdman

frizzle

michaelm

gui22a

BarryMachine

xx CURVE xx

Similar threads

Recent Discussions

Recent Discussions