Jump to content


Photo
- - - - -

Ducati motogp bike swing arm wing elements


  • Please log in to reply
14 replies to this topic

#1 pierrre

pierrre
  • Member

  • 81 posts
  • Joined: June 17

Posted 17 March 2019 - 01:36

this is an interesting take on ducati's swingarm scenario...how downforce is used by ducati

 



Advertisement

#2 Canuck

Canuck
  • Member

  • 2,072 posts
  • Joined: March 05

Posted 17 March 2019 - 15:02

That was interesting! I am always drawn in both by the ingenuity of racers and also by the detective work of people peeling back the layers of obfuscation on that ingenuity. 300hp...that’s a lot of bike.

#3 Kelpiecross

Kelpiecross
  • Member

  • 1,447 posts
  • Joined: October 10

Posted 18 March 2019 - 04:50

Perhaps surprisingly - I am not an expert on motorcycle aerodynamics - but I would not   have thought that wing would have any effect at all.  



#4 Kelpiecross

Kelpiecross
  • Member

  • 1,447 posts
  • Joined: October 10

Posted 19 March 2019 - 06:07

 A few seasons ago Ducati had small wings near the front of the 'bike which were meant to keep the front wheel down during acceleration - I doubt if they did anything either.

 

 The Ducati went well in the first MotoGP of the season - so something is working for them.    



#5 7MGTEsup

7MGTEsup
  • Member

  • 2,113 posts
  • Joined: March 11

Posted 09 April 2019 - 16:12

 A few seasons ago Ducati had small wings near the front of the 'bike which were meant to keep the front wheel down during acceleration - I doubt if they did anything either.

 

 The Ducati went well in the first MotoGP of the season - so something is working for them.    

 

 

I would think the problem with aero on a bike is that the bike changes orientation to massive degrees (literally) so making something that works well in all conditions must be near impossible.



#6 Joe Bosworth

Joe Bosworth
  • Member

  • 637 posts
  • Joined: May 05

Posted 10 April 2019 - 02:56

M/C dynamics are a very complex equation indeed and 7MGTE above starts to hit on one element,  Aero forces are so diverse as to be practically impossible to resolve through the riding elements of creating corner turn in under braking, maximise g forces while leaning at nearly up to 60 degrees off vertical, optimise acceleration forces while the front wheel lightens on throttle application and rear wheel download increases and the bike transitions to vertical and finally how to keep the front wheel close to the ground while loading the rear wheel.

 

All this needs to take place while giving the rider front to back force feedbacks.  For instance, Ducatti a few years back got themselves into a nearly un-ridable mode when they built too much stiffness into the frame.  Others from time to time have gotten the center of static gravity too low and engines had to be lifted. 

 

All  those things that the 4 wheel race designer knows to be have been solved ago have little to no application on 2 wheeled racers.  It is still almost a complete art form bounded by minimal legislation.  Is this why bike racing is so popular?  :clap:

 

Regards



#7 Kelpiecross

Kelpiecross
  • Member

  • 1,447 posts
  • Joined: October 10

Posted 10 April 2019 - 03:58

  I presume the main problem with downforce  on bikes is the fact that the  downforce must remain at a right angle to the road even when the bike is leaning over at 60 degrees - very hard to arrange movable wings to achieve this.  

 

 At least I assume that the downforce must be normal the road  - not at the same lean angle as the bike.   If the force was at the lean angle it would have a sideways component that the tyres would have to resist as well as centrifugal cornering loads .



#8 Greg Locock

Greg Locock
  • Member

  • 5,641 posts
  • Joined: March 03

Posted 10 April 2019 - 11:11

Exactly. It might help if you know what you tire characteristics are exactly, but most of the time it seems bad. So, either Ducati know more about bikes than we do (happy with that) or they have something that costs nothing and looks good (happy with that). or they are wrong ( quite possible). 



#9 blkirk

blkirk
  • Member

  • 318 posts
  • Joined: March 00

Posted 10 April 2019 - 14:09

Also, keep in mind that the rider moves around quite a bit in the seat.  The moveable aerodynamics involved with the rider makes the f-duct shenanigans look like child's play.

 

I wouldn't be surprised if Ducati has those foils positioned so that the rider stalls the airflow to one and/or both when he shifts position for cornering. 



#10 Ross Stonefeld

Ross Stonefeld
  • Member

  • 62,356 posts
  • Joined: August 99

Posted 10 April 2019 - 14:20

All the aero fairings on the front end are to help keep the nose on the ground during acceleration. I assume the primary gain is on corner exit but remember these things can wheelie in pretty much every gear so keeping the front wheel on the ground is often helpful. It probably has some downsides in high speed direction change but everything is a balance. If they're clever it probably also helps extract hot air from the engine.

 

Ducati's swingarm aero is claimed to be for cooling, and maybe it does gently blow on the tread surface, but if it is providing *any* downforce assistance to the rear wheel once the bike is upright that's going to help drive, tire temp, tire wear, etc. 

It's not going to suddenly gain 5 seconds a lap. But if it gains anything in single lap pace that's worth it. If it helps keep the tire under your or makes it more consistent over a race run, that's gold. 



#11 Lee Nicolle

Lee Nicolle
  • Member

  • 9,838 posts
  • Joined: July 08

Posted 11 April 2019 - 07:26

Aero on bikes is the fairing and drivers helmet. And that is all over the bike with head up [at least sometimes] for braking.

I am sure wings could be made to work on GP bikes but still probably create more drama than good.

Some drag bikes use small wings and supposedly work,,,,,,, though that in a straight line not bucking and weaving like most do.



#12 imaginesix

imaginesix
  • Member

  • 7,525 posts
  • Joined: March 01

Posted 11 April 2019 - 22:04

The front wing likely improves grip while cornering too, even if they don't say so. I can see how the airflow to the inside wing would be stalled by the rider leaning into the turn, effectively allowing the outboard wing to deliver downforce that the bike can use.

 

080417-jorge-lorenzo-motogp-ducati-new-f

 

Remember that for many years Ducati had a problem with the front end washing out with no warning, then as the front wing was developed that problem faded away.



#13 gruntguru

gruntguru
  • Member

  • 6,708 posts
  • Joined: January 09

Posted 11 April 2019 - 22:27

Great image - thanks imanginesix - now we all know what this thread is about.

The obvious wings - the foils immediately below the "TIM" logos would not be much help in a corner - however . . . 

The two element section connected to it is clearly designed to help during cornering - the lift vector is pointing towards the ground and angled toward the inside of the corner. The same goes for the fairing behind - the engine cooling inlet and the exit ducts are probably making a positive contribution. All of this of course depends on the rider's leg stalling/disabling the corresponding elements on the other side.



#14 Ross Stonefeld

Ross Stonefeld
  • Member

  • 62,356 posts
  • Joined: August 99

Posted 11 April 2019 - 23:06

No, because that's not a swingarm. And that's the 2018 bike. And the aero seen there, even if it does give a lean benefit(which I'm skeptical of) was designed to be useful when the bike was upright and hitting much higher speeds.

 

This is what we're discussing

 

_ax18599_uc71042_high.jpg?itok=tXIWlQBa&

 

 

 

 

And for a long time Ducati had a front end problem because they were running a carbon frame. 



#15 Youichi

Youichi
  • Member

  • 3,238 posts
  • Joined: January 04

Posted 12 April 2019 - 09:42

The best write-up of this I have read is at https://motomatters....ina_ducati.html

 

Ducati claim:

 

"and the results of our tests, .. is that we can reduce the temperature of the tire by about 7°C on average."

...

"In our case, I think that we can tell you that we have more or less 3, 4 Newtons at 180 km/h, 300 grams more or less."

 

But Honda claim:

 

It was that number which other factories disputed. Honda had done wind tunnel tests on a part with a very similar design to Ducati's, and had come up with very different figures. They had found that their device produced between 4 and 6 kg at maximum speed, or between 39 and 59 Newton.