2013 Critérium du Dauphiné Stage 4: Villars-les-Dombes Parc des Oiseaux 32.5 km ITT

[spalco]

What did he do?

 

[Cyivel]

What did he do?

Followed EBH for a long time

 

[Je ne sais quoi]

I watched the TT for a while and noticed

1) the SKY car was really very very close behind PORTE. Anybody has an idea how much the rider is helped by such a configuration? I would think it might be substantial.

2) Contador seemed to be spinning his legs a lot, not really pushing a big gear, but I didn't count his rpm.

There would definitely be a benefit both upwind and downwind of the car.

The place to look for the science involved is in the area of wind barrier effects. The most quoted research is probably meteorologist Alan Watts' 1967 Wind and Sailing Boats, and RW Gloyne's work in the 70's on hedgerow barrier effects for the British Met Office. In brief, they studied three types of barriers: dense (eg, a wall); medium (trees); and open (scattered trees, shrubs or other obstacles). Of course, they did not look at cycling specifically, but they measured where the orientation of the barrier was to windward (eg, like motor pacing in cycling); or where the barrier was to leeward (downwind, eg, like with a car following you).

To be very brief, the effect behind the barrier (eg like motor pacing) was measurable at 30x the height (h) of the barrier; the wind was at half speed at about 7h and at its lowest at about 5h.
In front of the barrier (eg, like with a following car) the wind "anticipates" the barrier by rising over the turbulence produced. The effect is less, but still important, the wind being at 90% strength at a distance of 9h in front of the barrier and half speed at 3h. So if a car was 1.5m in height, the wind would be noticeably less if the car was 4.5m behind you.

Of course cars are more aerodynamic than a wall or tree shrub, so the above figures would be mitigated, but the principle would remain. In a regular road race en ligne the fleet of support cars looks a lot like a classic open barrier.

 

[doperhopper]

What now? Skyborgs 1-2 or 1-2-3?

 

[Le breton]

There would definitely be a benefit both upwind and downwind of the car.

In front of the barrier (eg, like with a following car) the wind "anticipates" the barrier by rising over the turbulence produced. The effect is less, but still important, the wind being at 90% strength at a distance of 9h in front of the barrier and half speed at 3h. So if a car was 1.5m in height, the wind would be noticeably less if the car was 4.5m behind you.

So, if the stretch I saw was representative of the whole ride, PORTE really could have benefitted greatly from his support car. The distance was about 5 meters I would guess.

 

[manafana]

tony martin is different class, dennis exceeded my already high expectations for him here.

 

[oldcrank]

dennis exceeded my already high expectations for him here.

It's always good to see a track rider from a Commonwealth
country in a stage race leaders jersey even it turns out to
be only for one day. Well done, mate!!

 

[manafana]

It's always good to see a track rider from a Commonwealth
country in a stage race leaders jersey even it turns out to
be only for one day. Well done, mate!!

he rode pretty damn well today, with another year under his belt could be a bit more about him.

 

[oldcrank]

he rode pretty damn well today, with another year under his belt could be a bit more about him.

I agree, if he can avoid illness and injury, I think he will
have much bigger successes in the future.