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Thread: MotoGP 2013

  1. #826
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    Quote Originally Posted by wharfy View Post
    Well I don't know if that was the reason - but it would certainly be a nice side effect (if you were in front) don't know if it would be enough to counter the slipstream advantage.
    Actually with the amount of effort that goes into streamling today is it better for a bike to be in clean air or disturbed air ? ( I know from yacht racing sailing into another boats "dirty" air had an obvious detrimental effect)
    Also I remember reading that Ducati had some of the exhaust exiting up behind the rider to fill in the vacum behind them and help with aerodynamics. Do they still do that ?
    I don't know enough about fluid dynamics, but I understand the F1 guys have started moving the turbulent air from way beyond the back of the car to just behind the back of car in an effort to close the slip streaming volume. I wonder if this is the case for GP yet or at all?

    I can imagine the calculations and simulations into having the exhaust exit into the vacuum behind the bike is a scary one, you've got a less dense fluid entering a "vacuum" which is surrounded by turbulent flow etc etc fascinating topic.

  2. #827
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    Quote Originally Posted by Crasherfromwayback View Post
    Yep. Bass Straight without a doubt. I've been there many times and sat nearly everywhere. That did it for me. Turn three without a doubt is THE most exciting corner in GP racing IMO.
    but dont be afraid to move around a lot esp on the practise day(s),then you can see for your self.Siberia(from the hairpin up to Lukey heights) would be good too they go seriously fast up there

  3. #828
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    Quote Originally Posted by Crasherfromwayback View Post
    Yep. Bass Straight without a doubt. I've been there many times and sat nearly everywhere. That did it for me. Turn three without a doubt is THE most exciting corner in GP racing IMO.
    Thanks Mate, That will do me just fine.
    SOME PEOPLE ARE LIKE SLINKIES - NOT REALLY GOOD FOR ANYTHING BUT THEY
    BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS.

  4. #829
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    Quote Originally Posted by BMWST? View Post
    but dont be afraid to move around a lot esp on the practise day(s),then you can see for your self.Siberia(from the hairpin up to Lukey heights) would be good too they go seriously fast up there
    Some more good info, Thanks, Ill grab the Bass Straight stand and go for a cruise around.
    SOME PEOPLE ARE LIKE SLINKIES - NOT REALLY GOOD FOR ANYTHING BUT THEY
    BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS.

  5. #830
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    Quote Originally Posted by BMWST? View Post
    but dont be afraid to move around a lot esp on the practise day(s),then you can see for your self.Siberia(from the hairpin up to Lukey heights) would be good too they go seriously fast up there
    Yep. Best to do the wandering on the practice/qualifying days...then park yourself up for the main races I reckon.

    Quote Originally Posted by Smokin View Post
    Some more good info, Thanks, Ill grab the Bass Straight stand and go for a cruise around.
    Take warm/waterproof clothes. Only time I've been to PI without rain was last year. It can get FUCKING cold. Fucking hot too.

  6. #831
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    It looks as though the weather can be quite unpredicable there, Must be a mongrel for the bike techs. Thanks for the info guys.
    SOME PEOPLE ARE LIKE SLINKIES - NOT REALLY GOOD FOR ANYTHING BUT THEY
    BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS.

  7. #832
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    Quote Originally Posted by Smokin View Post
    It looks as though the weather can be quite unpredicable there, Must be a mongrel for the bike techs. Thanks for the info guys.
    It's like having a race track at Island Bay in Wellington.

  8. #833
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    Quote Originally Posted by Dave- View Post
    I don't know enough about fluid dynamics, but I understand the F1 guys have started moving the turbulent air from way beyond the back of the car to just behind the back of car in an effort to close the slip streaming volume. I wonder if this is the case for GP yet or at all?

    I can imagine the calculations and simulations into having the exhaust exit into the vacuum behind the bike is a scary one, you've got a less dense fluid entering a "vacuum" which is surrounded by turbulent flow etc etc fascinating topic.
    here a a simulation I did using a standard shape

    http://477-racing.webs.com/apps/vide...n-wind-tunnel-

    See the negative pressure building up under the back of the "car"

    Stephen
    "Look, Madame, where we live, look how we live ... look at the life we have...The Republic has forgotten us."

  9. #834
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    Quote Originally Posted by wharfy View Post
    Also I remember reading that Ducati had some of the exhaust exiting up behind the rider to fill in the vacum behind them and help with aerodynamics. Do they still do that ?
    Quote Originally Posted by Dave- View Post
    I can imagine the calculations and simulations into having the exhaust exit into the vacuum behind the bike is a scary one, you've got a less dense fluid entering a "vacuum" which is surrounded by turbulent flow etc etc fascinating topic.
    I remember reading somewhere that they turned/pointed the exhaust inwards on the big twins eg the RC51 because the turbulence was effecting the aerodynamics of the bike. Pretty sure my VTR and the SV are like this to???
    On a Motorcycle you're penetrating distance, right along with the machine!! In a car you're just a spectator, the windshields like a TV!!

    'Life's Journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out! Shouting, ' Holy sh!t... What a Ride!! '

  10. #835
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    Quote Originally Posted by Dave- View Post
    I don't know enough about fluid dynamics, but I understand the F1 guys have started moving the turbulent air from way beyond the back of the car to just behind the back of car in an effort to close the slip streaming volume. I wonder if this is the case for GP yet or at all?
    What they need is a fan blowing a high-speed jet of air out the back. The engine power required to drive the fan won't be wasted, because the jet will give thrust, and any bastard who tries to catch a draft will be picking himself out of the kitty litter wondering what happened.

  11. #836
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    Quote Originally Posted by Crasherfromwayback View Post
    Yep. Best to do the wandering on the practice/qualifying days...then park yourself up for the main races I reckon.



    Take warm/waterproof clothes. Only time I've been to PI without rain was last year. It can get FUCKING cold. Fucking hot too.
    I got off the plane at Tullamarine, 10am - 36 degrees.
    Drove down to the Island, 3.30pm - 6 degrees.

  12. #837
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    Quote Originally Posted by Brian d marge View Post
    here a a simulation I did using a standard shape

    http://477-racing.webs.com/apps/vide...n-wind-tunnel-

    See the negative pressure building up under the back of the "car"

    Stephen
    That is seriously cool, is that all open source?

    Quote Originally Posted by Reckless View Post
    I remember reading somewhere that they turned/pointed the exhaust inwards on the big twins eg the RC51 because the turbulence was effecting the aerodynamics of the bike. Pretty sure my VTR and the SV are like this to???
    Intuition tells me that exhaust gasses ought to be laminar (the opposite to turbulent) as they exit the exhaust, I would have thought the aerodynamics of the bike would effect the exhaust? Anyone?

    Quote Originally Posted by Badjelly View Post
    What they need is a fan blowing a high-speed jet of air out the back. The engine power required to drive the fan won't be wasted, because the jet will give thrust, and any bastard who tries to catch a draft will be picking himself out of the kitty litter wondering what happened.
    I wonder if jet propulsion is ruled out?

    My uncle was going to try running a jet engine in his TQ midget 30 odd years ago as apparently there was no rule against them, he just couldn't think of a way to manage the cars speed.

  13. #838
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    Pretty much any flow through a pipe is considered turbulent unless it has a very low velocity. Exhaust gases would be turbulent. Given the volume of air coming out of an exhaust compared to the air displacement caused by a bike going 300kmh or other speeds where drafting is effective I would thinki would have little effect on a following bike.
    I could see how positioning the exhaust to exit right behind the rider could help decrease the area of low pressure and help with top end speed

  14. #839
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    Quote Originally Posted by Asher View Post
    Pretty much any flow through a pipe is considered turbulent unless it has a very low velocity. Exhaust gases would be turbulent. Given the volume of air coming out of an exhaust compared to the air displacement caused by a bike going 300kmh or other speeds where drafting is effective I would thinki would have little effect on a following bike.
    I could see how positioning the exhaust to exit right behind the rider could help decrease the area of low pressure and help with top end speed
    So the 'hump' on the front of my leathers is of no help at all ? not even displacement ? ah huh .

  15. #840
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    Quote Originally Posted by roogazza View Post
    So the 'hump' on the front of my leathers is of no help at all ? not even displacement ? ah huh .
    lets keep this thread PG please.

    What I was saying is that if you are drafting someone, them adding a few m3 of exhaust gas to the area in front of you is likely to be insignificant when compared to the total volume of air you are already pushing through anyway.

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