F1/General Racing Question
Discussion
When does "Dirty Air" become "Slipstreaming"
For example, in yesterday's F1 the first four cars got close to each other and were then apparently caught in the dirty air of the car in front, so became a parade to the finish. But often (well not much anymore) we see cars slipstreaming on the fast straights and overtaking.
How is it possible to get out of the dirty air and into the slipstream? Cos Schumacher Jnr couldn't do it.
For example, in yesterday's F1 the first four cars got close to each other and were then apparently caught in the dirty air of the car in front, so became a parade to the finish. But often (well not much anymore) we see cars slipstreaming on the fast straights and overtaking.
How is it possible to get out of the dirty air and into the slipstream? Cos Schumacher Jnr couldn't do it.
I agree the two expressions are a little confusing but I'll have a go at explaining; basically slipstreaming is when the rear driver utilises the hole in the air being caused by the car in front to allow it to gain speed relative to the lead car due to it’s reduced drag, it can then pull out of the slipstream and use the momentum gained to carry it past. Good theory and something you would have seen often in F1 in the "good old days"! These days however, the cars are so finely balanced aerodynamically with front and rear wings, (front in particular in this respect) that as an F1 car approaches the rear of the car in front the turbulence (dirty air) will render the front wing ineffective, and as a result the car becomes uncontrollable at high-speed and the driver cannot pull out for fear of loosing steering input and control. Of course slipstreaming only works at higher speeds which correspondingly is when the front aerofoil have most effect! So there is a dichotomy of the two effects cancelling each other out. By contrast at slow speed the wing becomes less important but also slipstreaming has no effect! Hope that helps. Of course in GT racing slipstreaming does still work which is why you get better racing and more overtaking in GT's. Rich...
Just remember that the overall aerodynamic package is based on two details. How you deal with the viscosity of the air and how you leave it. The lift/drag basis of the first part is not new. Where it gets clever is in the second part. Control the vortices in a manner to leave the air as dirty as possible for a specific distance behind the car and you can effectively remove any possibility of slipstreaming. (note all those nice curled up edges, splitters etc) Similarly, in maximising the total efficiency in lift/drag you will also reduce the low pressure volume behind the car again reducing effective slipstreaming.
If you want slipstreaming these days you'd better switch to MotoGP
If you want slipstreaming these days you'd better switch to MotoGP
Or oval racing.
In the Winston Cup, there is an optimal gap between cars (about 27") where the air sees two or more cars as one entity. Not only do the following cars get a tow, but the lead car gets reduced drag. Get "hung out to dry" out of the queue and you can lose ten places in a lap.
With ChampCars and IndyCars running on the superspeedways, the cars run very small wings, so they can gain the tow but lose little in the way of downforce and grip. Champcars have run the Handford device (a bloody great plate behind the rear wing) on some circuits, which creates an even larger hole in the air for following cars. The tow is so great that it's almost impossible not to overtake, and there have been races with more than 100 lead changes. I think the record is about 160, just measured on the start line (possibly Michigan 500 in 2000, when Montoya beat Andretti by about 6"). Taking into account changes around the lap, there were more than 200 changes.
In the Winston Cup, there is an optimal gap between cars (about 27") where the air sees two or more cars as one entity. Not only do the following cars get a tow, but the lead car gets reduced drag. Get "hung out to dry" out of the queue and you can lose ten places in a lap.
With ChampCars and IndyCars running on the superspeedways, the cars run very small wings, so they can gain the tow but lose little in the way of downforce and grip. Champcars have run the Handford device (a bloody great plate behind the rear wing) on some circuits, which creates an even larger hole in the air for following cars. The tow is so great that it's almost impossible not to overtake, and there have been races with more than 100 lead changes. I think the record is about 160, just measured on the start line (possibly Michigan 500 in 2000, when Montoya beat Andretti by about 6"). Taking into account changes around the lap, there were more than 200 changes.
Damon Hill drove F1 through the period when all sorts of looney ideas were introduced to "slow" the cars down (as fast as the engineers tdreamed up ideas to make them faster) e.g. like grooved tyres, on an F1 car WTF! I remember him saying that you simply could not overtake by slipstreaming on a straight and out braking someone any more and as a result the fun went out of it for him. Notwithstanding comments about him as a driver, although as a 1 x World champion who could have had 2 x titles to his name I'll take his word on it! Rich...
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