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What's Wrong with the Ducati?

J4rn0

J4rn0

Joined Oct 2007
4K Posts | 744+
Tuscany, Italy
Some fodder for the long winter is needed!
wink.gif




So.. What's wrong with the Desmosedici?

While after the Valencia tests Preziosi is busy redesigning the front end of the bike, we may throw our own guesses at where the root of the problem lies.



Some have hinted at some basic flaw in the radical design of the bike's chassis, that makes it different from all the Jap variations of the venerable deltabox.

Some think it's actually the engine architecture that limits the choices for chassis.



Here are a couple of pictures of the 'naked' Desmosedici: first the old 990 version with trellis frame, then the new 800 with carbon fiber chassis.



Any ideas?







 
<
Something is wrong with this bike?





Honestly, I think they will figure it out soon. Its in the form of a Japanese sketch.



BTW, that's nice of you to give us a glimpse of Babelfish's superhero powers.
<
 
Jumkie said:
<
Something is wrong with this bike?





Honestly, I think they will figure it out soon. Its in the form of a Japanese sketch.



BTW, that's nice of you to give us a glimpse of Babelfish's superhero powers.
<
Click to expand...



Yes, but let's try our best guess, then we'll see who guessed right. No?



My guess is that having such a short mini-frame going from the cylinder heads to the steering head, there is not much room for designing in enough flexibility options (and the right flexibility in the front end is the key to riders' feeling). This could be one of the reason they switched from steel to carbon: carbon fiber is easier to adjust stiffness wise, in such a narrow space. The length of the 'frame' represented by the engine cannot change its rigidity at all -- it's just as stiff as possible, period.



For now they'll try to improve the existing mini-frame exploiting the possibilities of carbon fiber more, then if that fails their only path forward could be to design a completely new frame -- maybe still in fiber, but wrapping the whole engine and effectively joining the steering head to the swingarm pivot.



But that could require a change in the engine architecture as well... to centralize the masses properly in a deltabox-like frame, the 90° angle between the cylinders might have to be reduced to 75° or 72°. In that case, those who assert that the basic design is flawed will be confirmed right.





I may add that in the trellis version the front frame was longer and bolted to the sides of the heads, whereas with the carbon fiber it looks bolted to the valve covers -- even shorter...



What do you think?
<
 
The bike seems to accelerate well out of the corners & is up there with Honda's in a straight line (save Pedrosa). I think it is the stability on the brakes & turn it that is going to be needed for Rossi to be able to ride like he knows how.



How they do this is a real ball ache though as so many things can effect this area of performance so where do you start.



I think when the test riders were at Jerez the other week they were testing geometry & forks to name a few so i think this is the direction they seem to be heading. IF & its a big IF, they can get the front end right then maybe just maybe we will se the mighty screamer in action once again.



Oh yeah baby!!
 
J4rn0 said:
Yes, but let's try our best guess, then we'll see who guessed right. No?



My guess is that having such a short mini-frame going from the cylinder heads to the steering head, there is not much room for designing in enough flexibility options (and the right flexibility in the front end is the key to riders' feeling). This could be one of the reason they switched from steel to carbon: carbon fiber is easier to adjust stiffness wise, in such a narrow space. The length of the 'frame' represented by the engine cannot change its rigidity at all -- it's just as stiff as possible, period.



For now they'll try to improve the existing mini-frame exploiting the possibilities of carbon fiber more, then if that fails their only path forward could be to design a completely new frame -- maybe still in fiber, but wrapping the whole engine and effectively joining the steering head to the swingarm pivot.



But that could require a change in the engine architecture as well... to centralize the masses properly in a deltabox-like frame, the 90° angle between the cylinders might have to be reduced to 75° or 72°. In that case, those who assert that the basic design is flawed will be confirmed right.





I may add that in the trellis version the front frame was longer and bolted to the sides of the heads, whereas with the carbon fiber it looks bolted to the valve covers -- even shorter...



What do you think?
<
Click to expand...



Ducati tested a aluminum chassis & a carbon fibre back in 2008 i believe. Maybe a aluminum frame is option to get the flexibility right. Ducati

has stuck with the "L" configuration 90° between cylinders banks since they entered motogp where most have gone the narrow angle. Rather than change the angle could they possibly rotate engine in the chassis to achieve the same results.
 
I will preface this comment with the fact that I have no engineering knowledge past that of a layman.



With the engine being used as a significant part of the chassis the physical properties including dimensions, temperature, vibrations and centrifugal would all be variable under operation. Some of these variations may only be minute such as dimensions (metal expands as it gets hotter etc) but perhaps it is they that are making the bike unpredictable.
 
Gaz said:
I think it needs handlebars
<










Gaz
Click to expand...



Yup. And the bike in the second image needs rails as well
ohmy.gif




....ah, the "bikes that run on rails"!
rolleyes.gif








Not much overtaking, but it's a pleasure watching them ride!
laugh.gif
 
Mental Anarchist said:
I will preface this comment with the fact that I have no engineering knowledge past that of a layman.



With the engine being used as a significant part of the chassis the physical properties including dimensions, temperature, vibrations and centrifugal would all be variable under operation. Some of these variations may only be minute such as dimensions (metal expands as it gets hotter etc) but perhaps it is they that are making the bike unpredictable.
Click to expand...



This is an interesting observation. Race bikes work really hot all the time however, not so much dimensional variation related to temperature after all. I'm still more inclined to think their problem lies in the difficulty to get all desirable variations in the flexibility of the frame, compared to a deltabox. Guareschi at Jerez said that Preziosi is preparing a new more flexible mounting for the steering head for Sepang, and that seems to point to this kind of problems.



A carbon fiber deltabox would probably be a more final solution (maybe for 2012), and would remain something exclusive enough to preserve Ducati's image of technical originality.
 
J4rn0 said:
This is an interesting observation. Race bikes work really hot all the time however, not so much dimensional variation related to temperature after all. I'm still more inclined to think their problem lies in the difficulty to get all desirable variations in the flexibility of the frame, compared to a deltabox. Guareschi at Jerez said that Preziosi is preparing a new more flexible mounting for the steering head for Sepang, and that seems to point to this kind of problems.



A carbon fiber deltabox would probably be a more final solution (maybe for 2012), and would remain something exclusive enough to preserve Ducati's image of technical originality.
Click to expand...





I tend to think the 90 degree cylinder angle makes it difficult to build a chassis around. On the plus side, 90 deg. is great for vibration control; and who doesn't love those desmo heads? I would love to be a fly on the wall when the real engineers get together and discuss all of the options. Might make all of us seem uhh, ignorant.
 
J4rn0 said:
Yes, but let's try our best guess, then we'll see who guessed right. No?



My guess is that having such a short mini-frame going from the cylinder heads to the steering head, there is not much room for designing in enough flexibility options (and the right flexibility in the front end is the key to riders' feeling). This could be one of the reason they switched from steel to carbon: carbon fiber is easier to adjust stiffness wise, in such a narrow space. The length of the 'frame' represented by the engine cannot change its rigidity at all -- it's just as stiff as possible, period.



For now they'll try to improve the existing mini-frame exploiting the possibilities of carbon fiber more, then if that fails their only path forward could be to design a completely new frame -- maybe still in fiber, but wrapping the whole engine and effectively joining the steering head to the swingarm pivot.



But that could require a change in the engine architecture as well... to centralize the masses properly in a deltabox-like frame, the 90° angle between the cylinders might have to be reduced to 75° or 72°. In that case, those who assert that the basic design is flawed will be confirmed right.





I may add that in the trellis version the front frame was longer and bolted to the sides of the heads, whereas with the carbon fiber it looks bolted to the valve covers -- even shorter...



What do you think?
<
Click to expand...

I think it's a combination of things,if it would be one single thing it would have been figured out.

I agree with you that the materials/structure from engine to forks might be too rigid.I read somewhere they are going to try different (Don't know the English word) three-holed-plates connecting them to the frame.Tripleclamps?More flexing.

Maybe they will have to raise the whole bike so much they might be helped by putting the engine in a different position for instance.



I don't think they will change the engine at all.

Only the usual,trying different materials,shaving off or adding thickness here and there or whatever they do.But keep the general design.

i also think they will try out tons of different fairings,and at the end of the season they will wind up with a smaller one.Looking from the side.



So,my guess:

Tripleclamps and maybe front chassi.

Slightly different position of the engine in the frame.

Swingarm,fairings and forks,like everyone they probarbly have lots of options.(maybe they have decided on the main forkoption already)

Electronics perhaps.
 
Does the Ducati spinn the crank "backwards", ie. isn't that one thing Yamaha did for Rossi on JB's instruction? as it helps keep the front on the tarmac? Haven't heard much talked about all that kinda stuff yet, but we may hear such like.



Also on the CF v's Steel v's Ally frames, they all have there own resonances and flex rates but also hysteresis. They have a big job in front of them to get it just right for Rossi. And unlike those who keep saying "Ducati will do anything for Rossi" I am leaning toward the opinion that perhaps as much as Ducati will want to do whatever they can, they may not have the budget to allow it.



Seems a major reason Stoner seems very happy about his Honda move ........ that he will get what he ( and the other riders ) wants.

http://www.motorcyclenews.com/MCN/s.../December/dec0310-stoner-backs-honda-assault/
 
BarryMachine said:
Does the Ducati spinn the crank "backwards", ie. isn't that one thing Yamaha did for Rossi on JB's instruction? as it helps keep the front on the tarmac? Haven't heard much talked about all that kinda stuff yet, but we may hear such like.



Also on the CF v's Steel v's Ally frames, they all have there own resonances and flex rates but also hysteresis. They have a big job in front of them to get it just right for Rossi. And unlike those who keep saying "Ducati will do anything for Rossi" I am leaning toward the opinion that perhaps as much as Ducati will want to do whatever they can, they may not have the budget to allow it.



Seems a major reason Stoner seems very happy about his Honda move ........ that he will get what he ( and the other riders ) wants.

http://www.motorcycl...-honda-assault/
Click to expand...



If you look at the pics from the Valencia tests, you will notice that the rear wheel was pushed fully forward in the swingarm, same thing we saw on the Yamaha when they first tried the Bridgestones, and that eventually let to a new modified swingarm.



About Ducati not having the money to implement changes Rossi may ask for, well, that sounds ridiculous to me, honestly. The limitation in this regard will be time (and testing time) from now to Qatar, not money, that surely has already been allocated.
 
J4rn0 said:
If you look at the pics from the Valencia tests, you will notice that the rear wheel was pushed fully forward in the swingarm, same thing we saw on the Yamaha when they first tried the Bridgestones, and that eventually let to a new modified swingarm.



About Ducati not having the money to implement changes Rossi may ask for, well, that sounds ridiculous to me, honestly. The limitation in this regard will be time (and testing time) from now to Qatar, not money, that surely has already been allocated.
Click to expand...

wasn't the shorter swing arm something rossi loved on the m1 in 2004?

correct me if i'm wrong but i think its rossis preference to have the swing arm as short as possible as he chooses agility over stability if you want to put it like that
 
cliché guevara said:
wasn't the shorter swing arm something rossi loved on the m1 in 2004?

correct me if i'm wrong but i think its rossis preference to have the swing arm as short as possible as he chooses agility over stability if you want to put it like that
Click to expand...



If i recall when Rossi got on the 2004 M1 they were running the wheel as far back in the swingarm as they could, and then made a longer swingarm which made the bike more stable into the turns. It wasn't until they changed to Bridgestones that they started going short on the swingarm again and that was about weight distribution i think.
 
cliché guevara said:
wasn't the shorter swing arm something rossi loved on the m1 in 2004?

correct me if i'm wrong but i think its rossis preference to have the swing arm as short as possible as he chooses agility over stability if you want to put it like that
Click to expand...

I remember that too.Also,I read about at the end of the season Stoner used a shorter swingarm(when they found a good set up from Aragon onwards)as well as different rider position.Maybe they were on to something then,and maybe it's a similar situation,as Rossi/Burgess tried even shorter swing arm.

As i understand,the FIAT Yamaha has a really good weeliecontrol,i don't know if the MarlboroDucati has the same.



I'm guessing the chassi isn't going to take that long to change to Rossi's liking.But maybe the electronics combined with the chassi though.How they work together.
 
After the recent Jerez tests, Vitto Guareschi commented that they did not try any new parts (not yet ready) but they experimented more with weight distribution following Rossi's indications and, according to him, they reached a point "they had never reached before" in terms of user friendliness of the bike -- he said the bike felt easier and less tiring. He clocked 1.42.1 which is not too bad for a 40 yrs old ex test rider in a winter day. (track record is in the 1.39sh if I remember well).



The new parts expected for Sepang are practically the entire "frame" (steering head and swingarm) in carbon fiber, built with different (less) stiffness (no info about dimensions). If just by changing the weight distribution the present bike reacted well, with the new parts it could improve further.
 
J4rn0 said:
After the recent Jerez tests, Vitto Guareschi commented that they did not try any new parts (not yet ready) but they experimented more with weight distribution following Rossi's indications and, according to him, they reached a point "they had never reached before" in terms of user friendliness of the bike -- he said the bike felt easier and less tiring. He clocked 1.42.1 which is not too bad for a 40 yrs old ex test rider in a winter day. (track record is in the 1.39sh if I remember well).



The new parts expected for Sepang are practically the entire "frame" (steering head and swingarm) in carbon fiber, built with different (less) stiffness (no info about dimensions). If just by changing the weight distribution the present bike reacted well, with the new parts it could improve further.
Click to expand...



Well look where "user friendliness got them in the past
<




JB sounds the least confident about next season than he has ever http://www.motorcyclenews.com/MCN/s.../dec0610-burgess-expects-big-honda-challenge/

Extolling the virtues of Honda and he believed Rossi was in a good position for the 2011 title on the Yam, before they left ....... all sounds very negative.
<
 

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