Ross Tucker Does Not Understand Aerodynamics/Wind-Tunnel

My misgivings aside, I think it's pretty cool that the Ross Tucker, the go-to-sports-scientist of much of the world's media, posts here. The brojos should authenticate him by giving him a red tag, like Coach Renato Canova's ... speaking of which, I see an epic fight about the effect of EPO on elite Kenyans and Ethiopians.

El Keniano wrote:

Bombly wrote:

Show us your credentials then?

Not a scientist, I'll tell you that. Nor do I pretend to be one - just a mere fan of the sport and I never proselytise.

So you admit that he has the knowledge, has done the research, and fine the testing to have an expertise that you will never have.

If my running speed is 3'30"/km , running with a pacer formation like Monza

and also behind a car that keep the speed constant at 2'51/km ,doesnt give me any advantage and of course I just drop out.

But if my Marathon speed is of 2'53"-2'54"/km running in those conditions in a pack that keeps 2'50"-2'51"/km gives me of course great advantage and chance to follow that pace that IS NOT SO FAR FROM KIPCHOGE REAL MARATHON PACE.

Thats what happened to Eliud Kipchoge.

While Tadese and Desisa were not able simply cos 2'51"/km was that day

too FAR pace for their REAL MARATHON PACE.

Is a very delicate balance the draft in running , a lot different from draft in cycling where the advantages of those that stay covered in the group are really enormous..

Ha, thanks for that picture. Kipchoge is about 30m behind the damn car, not even close enough for a draft... and that's 18 min into the race.

HGL wrote:

..

Furthermore, the car left Kipchoge shortly after 35km, after he was no longer able to keep pace.

Don't be ludicrous. This is like saying, but officer, I didn't drink the whole bottle of alcohol while I was driving--see, look, there is a little bit left!

rojo,

I just read that Power of Eliud Kipchoge article, and it's interesting, but they themselves are not as enthusiastic with it as much as you are. They say themselves that is all from theory and they don't have real time power and aerodynamic data.

First of all they are plugging in theoretical power data into a calculation, then theoretical fade in power, and theoretical aerodynamic coefficients. That's too much theoretical stuff stack on top of each other for confidence in results. A few percent here and there difference in actual results would be expected if they could do field trials.

For their calculations, they assumed that all of the benefits come from aerodynamics. They didn't include any possible benefits from shoes and paying closer attention to running tangents than a normal marathon due to rolling feed and better attention to detail.

Even if every second of benefit was from aerodynamics, the article provides no insight into the relative worth of possible aerodynamic benefits - 3 pacers vs. 6, 6 randomly arranged pacers vs. 6 pacers in triangle formation, pace car with clock in front 6 meters ahead of pacers/ 10 meters ahead of Kipchoge. You really think that the clock was all of the gain and not the running pacers?

The article's "normal pacers" scenario was 3 pacers to 25-30 km. Having just running pacers go all the way to the finish is 53% more benefit (by distance 42.2/27.5=1.53) right there in aerodynamic benefit without counting any possible benefit from the clock. They could have easily done the math on that. They gave him 1:31 of benefit (2:03:49 to 2:02:18) from having three pacers to 27.5 km over having no pacers at all. If you have 3 pacers go to the finish instead of 27.5 km, shouldn't you get 53% more time benefit? That could cut 2:02:18 to 2:01:30, just from having 3 pacers go all the way to the finish.

Going from 3 pacers to 6 pacers in triangle formation is another very big aerodynamic benefit compared to "normal pacers" that is not the clock on the car. It's like drafting on the bike in a small group vs. being in the middle/back of a large peloton. And of course, it went all the way to the finish too, though there were times near the end when the front 3 went off the front a bit. I could see that giving the all of the rest of the theoretical aerodynamic benefit. It's got to be a lot better than 3 pacers - my instinct, anyway.

The Tesla kept going at 2 hour pace when Kipchoge couldn't keep up, so the clock couldn't have helped after 37 km too.

My guess of the benefits over the current WR are maybe 15-20 seconds from rolling feed/better able to run tangents, maybe something from the shoes depending on what you are comparing it to, maybe 30 to 60 seconds from having better pacing than most WR attempts, a lot from Kipchoge just being a bigger BOSS than Kimetto, and the rest from aerodynamics of the 6 running pacers, with the clock on the Tesla as possibly from 0 to 20 percent of that total aerodynamic benefit. I don't know what proportion of the aerodynamic benefit is from the car/clock, and I'd be happy to see someone run some tests, but I think it's on the low side if any - unless shown otherwise by well run field testing.

logicshouldbecomeyou wrote:

HGL wrote:

..

Furthermore, the car left Kipchoge shortly after 35km, after he was no longer able to keep pace.

Don't be ludicrous. This is like saying, but officer, I didn't drink the whole bottle of alcohol while I was driving--see, look, there is a little bit left!

But it is highly relevant as *if* this was going to be the most important factor in going sub-2, why would you remove it just when the guy needs all the benefits he can get to squeeze every last second out of his fatigued body.

This factor alone makes me think that the car was not considered by Nike or the runners to be a particularly significant part of the benefits that they could give to the three athletes trying to go sub 2.

Having said that, I would equally accept that they've clearly not put that car in there not knowing whether at that distance it would be a net benefit or net harm to the attempt.

zzzz wrote:

My guess of the benefits over the current WR are maybe 15-20 seconds from rolling feed/better able to run tangents, maybe something from the shoes depending on what you are comparing it to, maybe 30 to 60 seconds from having better pacing than most WR attempts, a lot from Kipchoge just being a bigger BOSS than Kimetto, and the rest from aerodynamics of the 6 running pacers, with the clock on the Tesla as possibly from 0 to 20 percent of that total aerodynamic benefit. I don't know what proportion of the aerodynamic benefit is from the car/clock, and I'd be happy to see someone run some tests, but I think it's on the low side if any - unless shown otherwise by well run field testing.

Editing myself, I'd lower the benefit from even pacing a bit because I don't know how evenly paced the existing WR was. Move most of that time to aerodynamic benefits, which I think were dominated by having 6 running pacers all the way to the line.

Just to put some maths behind the "shortest route" argument.

If we model a marathon as being equivalent to a straight line of 42,195m and break it down into 1000 segments measuring 42.195m and then ask how far from the straight line would a runner have to deviate for the whole marathon to actually be 42,295m long (i.e. 100m) we find that the runner would have to deviate by 1.45m out from the perfect line and back again to get that sort of error.

To me that would seem like quite an erratic route, not far off equivalent on a track to deviating twice every straight and twice every bend from lane 1 to lane 2 (and then a bit) and back again consistently every lap for 105 laps. Or from lane 1 to nearly in lane 4 every 100m and back in again.

In summary, deviating from the line is probably not worth a huge amount, perhaps even the 15-20s advantage given above is pushing it a bit for an elite marathoner in terms of how far and how often they deviate from the measured shortest route.

Then why does my GPS usually read 26.4-26.5 on marathons. I'd say that is worth more than 15-20s.

You will get a bit of stutter stepping/slow down at each normal aid station, so not all that time advantage is from just slightly shorter distance. Also for each right angle turn where a runner is, say, 3 meters out from the corner is adds almost 5 meters (1/2*pi*distance from apex), which adds up quicker than the straight line deviations. If the benefit from having rolling aid/easier tangents to follow is less than 15 seconds, I wouldn't disagree with you.

I forgot to add that the BOSS factor of Kipchoge seems to be about minute. At least that's what a lot of people seemed to say after his run - that no one on earth would likely have finished within a minute of him.

The marathon was measured by one of the top IAAF certified course measurers and he was there to observe the run as well (not a race).

The distance has to be 42.195kms + 1m per km added over the shortest possible route. So a marathon will always read long if it is measured properly.

Because the Berlin course is where something like nine of the top-15 ratified times has occurred, it is the course that this time is held up against, or the performances are, like the current world record held by Dennis Kimetto 2:02:57.

If you look at the map of the Berlin course, there appears to be 32 +/- corners and several more sharper-than-a-race-track curves.

What happens when we turn a corner, running fast? Does it add half a second per corner? throw the rhythm? What happens to the drafting effect when we turn a corner?

How many aid stations are there in Berlin and how many did Kimetto alter his pace/rhythm to get his water bottles? One second per station?

As for the shoes, someone mentioned that the carbon plate in the shoes is a concern because then the runner would be aided, not unlike Oscar Pistorius's carbon-fibre prosthetic legs.

Clearly the (is it vertical oscillation?) vertical bounce/recoil and or forward or upward benefit is going to be much more beneficial for Oscar's performance because of the length of the carbon prosthetic. Whereas with the shoe, the plate could only provide a few mms of drop on impact to create recoil - but over a marathon, is there really a benefit? I would assume there is much less and Nike just did another genius marketing exercise. Fair and why not? The heels hardly touch the ground, the part of the shoe towards the toe-box has less outter sole, the back of the shoe is where there is room for drop....

Regarding the wind turbulence created around the back of the Tesla and clock box, wouldn't turbulence be more beneficial than flat/steady air?

I am thinking that the run didn't so much as demonstrate that a man can run under 2:00:00 (eventually, although I guess it may have), but rather how much you have to throw at a marathon in assistance for someone who is world record capable to get near the benchmark.

Kipchoge is a great athlete, but I am going to throw my hat in the ring of he being good in a race like Berlin for about 2:03 +/- 5s on an ideal day after ideal training.

Can someone tell me what Ross Tucker's degrees are actually in?

I agree I would not want someone with degrees in biology or exercise physiology to spout off knowledge on fluid dynamics like they are an expert just because they went to college and studied something else. I'm sure Mr. Tucker feels irritated when the reverse happens and say a non-medical professional gives medical advice.

Ross, I enjoy reading your stuff. The article linked on the previous page does a very convincing job in calculating the effect without having to know the size of the clock. Now, the car is 54.5" high, the rack several more inches, and the sign probably about 50" high or more. So, they are drafting off a surface that rises about 106" off the ground, close to 9', maybe more. As soon as I saw how close they were behind the car at the start of the race I posted that the screen was going to likely let them go close to 2 hrs. But now that it has been done, Ross, I believe that you are going to see the confidence in the runners to allow big drops in time, just as you did right after the wind-aided Boston marathon of 2011 when Mutai and Mosop ran 2:03. Kipchoge just got the chance to actually run a 2:00:25 marathon. His legs are now used to running 4:35 pace for a marathon. I believe that for him, despite his major advantage of about 2' from drafting, he will now have the cadence and confidence to destroy the world record and a sub 2:02 would not surprise me in the least in Berlin if he recovers well from this race. And it will not change the fact that he simply could not have done this performance without the drafting from the car. But he will be joined within the next year or two by others under 2:02, and sub 2:01 legit will happen a lot sooner than you expect, by 2020, maybe even this year or next.

GetOffMyLawn wrote:

Can someone tell me what Ross Tucker's degrees are actually in?

I agree I would not want someone with degrees in biology or exercise physiology to spout off knowledge on fluid dynamics like they are an expert just because they went to college and studied something else. I'm sure Mr. Tucker feels irritated when the reverse happens and say a non-medical professional gives medical advice.

Not everything is learned in college.

Another giver of +1 wrote:

+1

If there was no slipstreaming advantage to be had Nike wouldn't have stuck a butt-ugly 2m x 1.5m square clock on the top of the Tesla.

If you don't event know what a square is, you clearly can't comment on aerodynamics.

Sdfsdfsdfsdfssczzczdc wrote:

Another giver of +1 wrote:

+1

If there was no slipstreaming advantage to be had Nike wouldn't have stuck a butt-ugly 2m x 1.5m square clock on the top of the Tesla.

If you don't event know what a square is, you clearly can't comment on aerodynamics.

If you think "event" works in that sentence, you clearly can't comment on geometry.

Lomum wrote:

GetOffMyLawn wrote:

Can someone tell me what Ross Tucker's degrees are actually in?

I agree I would not want someone with degrees in biology or exercise physiology to spout off knowledge on fluid dynamics like they are an expert just because they went to college and studied something else. I'm sure Mr. Tucker feels irritated when the reverse happens and say a non-medical professional gives medical advice.

Not everything is learned in college.

I will accept proof that Tucker has had experience in doing wind tunnel testing, aerodynamic analysis, etc.

We know drafting helps athletes. No one has proven that the car itself provided a drafting advantage.

Dr. Oz is a cardiologist but no one here buys all his crap, I don't think asking "scientists" to back up their assertions with real evidence is too absurd.

Because you don't have to deviate for your GPS to think you are.