MotoGP 2013

[Dave-]

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.

[BMWST?]

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

[Smokin]

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.

[Smokin]

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.

[Crasherfromwayback]

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.

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.

[Smokin]

It looks as though the weather can be quite unpredicable there, Must be a mongrel for the bike techs. Thanks for the info guys.

[Crasherfromwayback]

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.

[Brian d marge]

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

[Reckless]

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 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???

[Badjelly]

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.

[Oscar]

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.

[Dave-]

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?

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?

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.

[Asher]

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

[roogazza]

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 .

[Asher]

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.