Ducati switch to big bang for 2010
in [Racing]
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From: Champ on 14 Jan 2010 05:23 http://www.motogp.com/en/news/2010/the+new+ducati+desmosedici+gp10 The previous 800 bikes were screamers, but for this year it's going to be a big bang-er. I think this is quite a significant change, and might make it more rideable for anyone whose surname isn't Stoner. -- Champ neal at champ dot org dot uk
From: Julian Bond on 14 Jan 2010 07:42 Champ <news(a)champ.org.uk> Thu, 14 Jan 2010 10:23:56 >http://www.motogp.com/en/news/2010/the+new+ducati+desmosedici+gp10 > >The previous 800 bikes were screamers, but for this year it's going to >be a big bang-er. What I find quite interesting is looking at the photo and trying to work out what might appear on road bikes. Like:- - A properly integrated and styled double bubble screen and upper fairing that actually provides some rider wind protection - BIG swingarms - Fully faired belly pan - Completely hidden exhausts - Composite and integrated sub-frame, seat support And hidden away, Ducati using an extremely minimal frame-airbox Ducati are clearly doing a lot of wind tunnel work. I wonder how much the rear seat and top exhaust exit was influenced by that. -- Julian Bond E&MSN: julian_bond at voidstar.com M: +44 (0)77 5907 2173 Webmaster: http://www.ecademy.com/ T: +44 (0)192 0412 433 Personal WebLog: http://www.voidstar.com/ skype:julian.bond?chat Tread Lightly
From: les on 14 Jan 2010 11:14 On Thu, 14 Jan 2010 10:23:56 +0000, Champ wrote: > The previous 800 bikes were screamers, but for this year it's going to > be a big bang-er. for the terminally hard of thinking, would you kindly explain the difference. both in the engine and the riding style required. and no I'm not trolling TIA
From: Julian Bond on 14 Jan 2010 11:42 les <me(a)nowhere.com> Thu, 14 Jan 2010 16:14:59 >On Thu, 14 Jan 2010 10:23:56 +0000, Champ wrote: > > >> The previous 800 bikes were screamers, but for this year it's going to >> be a big bang-er. > >for the terminally hard of thinking, >would you kindly explain the difference. > >both in the engine and the riding style required. > >and no I'm not trolling It's a V4 with pairs of conrods on a single crankpin. The two crankpins and hence pairs of pistons can be inline (360), opposed (180) or somewhere in between. It's a 4-stroke so the ignition timing can then fire each piston in lots of different orders. The most extreme is to have a 360 crank, fire both cylinders in a bank together and then the other bank 90 deg later. It's believed Ducati have tried this at some stage. The other extreme is space everything out as far as possible so it's then close to being equal amounts of crank rotation between each firing point. This is the screamer layout that they've been using recently. The next complication is the variation in rotation as a piston goes to TDC and BDC. The change in momentum as the piston comes to a stop is what Yamaha are trying to avoid with their cross plane crank. V2 and V4 are inherently good for this as one piston is moving at more or less maximum speed when the other is stationary in a V pair but it's not completely perfect. Then we get onto exhaust and intake tuning. Even firing is good for exhaust tuning when cylinders are paired or grouped into one exhaust. Even intake cycles are good for air box design as it smoothes out the air demands. What Ducati are believed to be doing now is pairs of fairly close firing with an even space between the pairs. This is a compromise that doesn't reduce peak power too much. But the kind of soft big bang effect still let's the tyre re-grip between firing pulses and should make it easier for the rider to feel for the point where the tyre is beginning to spin up. That may also make it possible to use less traction control and hence allow the rider to get closer to the limits. Ducati have had trouble with the rear suspension pumping as the tyre grips and slides so it may also help to smooth out the transition from one to the other and hence reduce chassis pump. Even Ducati seem to be saying there's a lot of guess work in there! And smoother is all a relative term. These are still scary missiles. You get the feeling if the bike is smoother, Stoner will just ride it harder until it's almost out of control again. One other thing I find interesting in those interviews is Domenicali saying that MotoGP engines are going to have to be more reliable than street engines with the restrictions on engine rebuilds. That is, run a street engine as hard on the racetrack and it would need more frequent rebuilds. They're also looking at ways to save the engine in the event of a crash. I guess that means better air filters and a quick cut off to kill the engine when falls over in the gravel trap. Perhaps also crash rubbers to protect the crankcases. Ducati sponsored by R&G? -- Julian Bond E&MSN: julian_bond at voidstar.com M: +44 (0)77 5907 2173 Webmaster: http://www.ecademy.com/ T: +44 (0)192 0412 433 Personal WebLog: http://www.voidstar.com/ skype:julian.bond?chat Tread Lightly
From: les on 14 Jan 2010 14:13
On Thu, 14 Jan 2010 16:42:41 +0000, Julian Bond wrote: > les <me(a)nowhere.com> Thu, 14 Jan 2010 16:14:59 >>On Thu, 14 Jan 2010 10:23:56 +0000, Champ wrote: >> >> >>> The previous 800 bikes were screamers, but for this year it's going to >>> be a big bang-er. >> >>for the terminally hard of thinking, >>would you kindly explain the difference. > > It's a V4 with pairs of conrods on a single crankpin. My thanks |