Huh? We know that to increase RPMs when trying to increase displacement requires an increase in bore once you've hit the max piston speed (~26M/second). That means the bore is a "freebie" when counting rotations. Since 81mm is the limit on bore and 81mm doesn't present huge engineering problems in terms of combustion, it seems completely illogical to consider that any of the factories would use anything but an 81mm bore. So, the assumption is sound.
Given that and the reported RPMs, the calculations are also sound. In order to rev higher than the competition with consideration to the 81mm bore limit, you've only got one option: reduce displacement.
This also explains at least a little bit of the power delivery issue the riders have complained about.
Why the "Huh?"
Isn't all that what I wrote: "Seems to be a based on assumed bore size, an assumed max mean piston speed and a decent analysis of max rpm". Perhaps you're taking 'assumption' as a perjorative? I was surprised that from Geonerd's link, it would seem that the speculation began with an observation of a tacho scale.
Kinda off-topic: Why assume 26m/s as a maximum MPS? After all, NASCARs with 4.185" bore x 3.25" stroke run higher MPS than 26m/s....Note we're talking Mean Piston Speed here not Max Piston speed, that'd be 30+ m/s ...
MPS is really an indicator of the potential an engine might have. It's a good number to use to examine the theoretical performance of an engine, but not an actual indicator of the specific limitations an engine may have. That is, what specifically is the limitation that Mean Piston Speed represents?
Zaphod wrote:With Qualifying being what it is, in so far as if you manage one quick lap (in variable conditions), and then during the race, by really hanging your neck out, you manage to stay with the fast bikes for three laps until their tyres warmed up, at which point they just rode away to leave you one place higher than your team-mate, I'd still take both sets of data into account.
Be realistic about it. All Hayden's efforts (no critique of rider implied or intended) amounted to was a gap 6-odd seconds up the road from his team-mate. One started back and went forwards a bit, one started forwards and went back alot.
They both sound like they know where the issue is............power delivery. That's what both riders are implying is responsible for the tyre degradation and handling issues. Two different riding styles and approaches are pointing to the same underlying issue........... as well as resulting in both bikes finishing every race in close proximity to each other.
Why is Hayden the saviour all of a sudden, after one good effort ?
I also belive having two sets of data is going to help you more than having just one set.
But you don't even need to do any math to figure that is the Ducati is revving higher it is a smaller displacement.
Zaphod wrote:I take some solace in seeing that, although the carbon frame may not have been the cause of the issues, by removing it ( and it's own quirks that need to be sorted) they have isolated (time will tell) where the root cause of the problems seem to lie. I thought at the time (and said as much.....mug's guess) that although the frame may or may not have been the problem, removing it would be a step I would take, if for no other reason than to simplify the equation.
At the start, I could see that it would be easy to get lost in trying to identify the problem..........is it the frame ? Is it the suspension/tyres ? Is it the engine ? Once they get this power delivery issue sorted, then you could, in all probability, return to the CF design knowing that any issues you were then trying to solve were purely geometry/flex etc related.
I hope the CF does come back..........when the bike is working better.
....With the exception of Marquez's current trick of shoving people onto ripple strips to get by while costing them time. That's an arse of a manouvre. Nice work by Redding in showing him the best way to cost someone time is to shove yourself, and the following freight train up the inside in a slow corner.
Classy payback from the young man.
Worried Marquez is going to keep doing this until someone gets hurt. It took my breath away to watch Redding on a wet ripple strip. Maximum credit to him for
a) still being able to pull it up and fall in behind
b) Not sinking to Marquez's level.
Zaphod wrote:As a side note, or stupid opinion, Jarvis's attitude is starting to bug me. He seems quite happy to revel in the performance of a bike that was rubbish until he employed the people who he is now quite happy to deride , in small, snide ways.
Zaphod wrote:The "opinion" bit was refering to me, and my personal (probably wrong and ill-informed) take on how Jarvis is coming across these days.
Zaphod wrote:I like different views, as they help me to learn, as well as combat my own biased opinions.
To get back on track, what effect does anyone see Germany invading Italy having on the whole Super Duc racing effort ?
Gustav O wrote:Zaphod wrote:As a side note, or stupid opinion, Jarvis's attitude is starting to bug me. He seems quite happy to revel in the performance of a bike that was rubbish until he employed the people who he is now quite happy to deride , in small, snide ways.
I think you are making a to big deal out of Rossi/Burgess importance on the development of the M1 and discarding Furusawas importance. Rossis praise for Masao is possibly even stronger than for JB and Yamaha did also step up their game in every aspect for the 2004 season and have had a good directions since.
Anyway, just another opinion.
Rossifumi wrote:Furusawa has high praise for Rossi too. Lets not forget that during the 2004, 2005, 2006 and 2007 seasons only Rossi managed to win on the Yamaha - quite a few winners, on both factory and sattelite bikes, won on the Honda in the same time period. So Furusawa may well have done a good job but maybe Rossi/Burgess flattered the bike in the early days too? Jarvis and Yamaha owe them a lot.
Gustav O wrote:Rossifumi wrote:Furusawa has high praise for Rossi too. Lets not forget that during the 2004, 2005, 2006 and 2007 seasons only Rossi managed to win on the Yamaha - quite a few winners, on both factory and sattelite bikes, won on the Honda in the same time period. So Furusawa may well have done a good job but maybe Rossi/Burgess flattered the bike in the early days too? Jarvis and Yamaha owe them a lot.
They are of course all part of the process but Yamaha had one outstanding rider and a bunch of support riders who didn´t win much before or after riding the Yamaha ( Checa, Edwards, Abe, Elias, Xaus etc. etc.) When they got two great riders the bike started winning with them on as well.
I am not trying to discredit Rossi or Burgess here, just trying to point out how important Furusawas and Yamahas effort was.
Gustav O wrote:... I think it is strange to say that the riders input and data is NOT valuable for the team. What else do they have to work from? Imaginary information if they would have gone faster?
redmike34 wrote:Let's use Nicky as the constant over the last four years--the following numbers represent the average gap to race winner, best gap to race winner, worst gap to race winner for Nicky since 2009, all in seconds. This excludes the three races in which he got lapped, any race he didn't finish, and is not adjusted for weather, etc.:
2009: 37.2, 12.9, 61.2
2010: 19.3, 1.9, 50.7
2011: 36.9, 23.0, 76.3
2012 is only two races old, but it isn't reminding me of 2010 just yet. For Nicky, at least, the Ducati seemed to progress significantly from 2009-2010.
TwoStroke Institute wrote:Stroke is what governs max rpm not piston speed. The difference in stroke between a 81mm bore 930 and 1000 is 3mm on a very short stroke engine which is negligable. Ducati would just have a higher rpm limit.
Hanuman wrote:chasing horsepower via revs and losing tractibility in the lower ranges.
dave_m wrote:Hanuman wrote:chasing horsepower via revs and losing tractibility in the lower ranges.
So how much of Ducati's throttle response problems would just be fixed by trying to get 240HP out of a 1000cc engine instead of 250HP out of 920cc engine?
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