CDA - AERODYNAMICS - DRAG: influence of motorbikes, bike position etc

[Merckx index]

I'd like to see a study comparing different sized groups. We've all seen small breakaways, say, 10-12 riders, get caught by the peloton. I guess the peloton is driven by fresher riders, but probably no more of them than alternate in the break. If there are two or three of them, the draft advantage would be greater, but the break could do the same thing.

So is it just the fresher legs, or a size advantage?

 

[sir fly]

Re:

I'd like to see a study comparing different sized groups. We've all seen small breakaways, say, 10-12 riders, get caught by the peloton. I guess the peloton is driven by fresher riders, but probably no more of them than alternate in the break. If there are two or three of them, the draft advantage would be greater, but the break could do the same thing.

So is it just the fresher legs, or a size advantage?

It's not everything in Φ ... φ

 

[Logic-is-your-friend]

Re:

I'd like to see a study comparing different sized groups. We've all seen small breakaways, say, 10-12 riders, get caught by the peloton. I guess the peloton is driven by fresher riders, but probably no more of them than alternate in the break. If there are two or three of them, the draft advantage would be greater, but the break could do the same thing.

So is it just the fresher legs, or a size advantage?

This was actually (at least in part) explained in the research/interview in the opening post. Whether a bus, car or peloton is riding directly behind a cyclist, as long as it is a "large mass" that displaces air by moving, the rider in front will benefit from it, because it pushes the air in front, forward. Thus "protecting" the leading rider. However, this advantage is obviously a lot smaller than the advantage of riding behind a large mass. See the image with Delgado, chased by cars and motorcycles, and the image with the motorcycle riding behind the cyclist. There's supposedly still a reasonable advantage to be had.

Additionally i believe that even though the amount of riders taking pulls might be the same in both the peloton as the break, that the riders that are in the peloton, might "drop further back" inside of the peloton, and stay a lot more fresh than the riders in the break, even when they're currently not pulling.

 

[ClassicomanoLuigi]

Re: Re:

I'd like to see a study comparing different sized groups. We've all seen small breakaways, say, 10-12 riders, get caught by the peloton. I guess the peloton is driven by fresher riders, but probably no more of them than alternate in the break. If there are two or three of them, the draft advantage would be greater, but the break could do the same thing.
So is it just the fresher legs, or a size advantage?

Suppose that pulling on the front of a group is (an expectation) to do about 40% more work. The 12-rider breakaway that you mention as an example is becoming dangerous for the win, because if they choose to work together as a rotating double-paceline, each rider only has to take short pulls at the front, 30 seconds is enough, then 30 seconds on the front of the second, regressing paceline, and so it's 1 minute 'on' / 5 minutes 'off'. Lots of time to recover, especially for professionals, they can do that again and again.
The peloton in a mass-start race can't all rotate like that, because a two-lane road is not wide enough, because of lack of coordination between teams or individuals, and not much incentive to be on the very-front leading edge. There will be an arrowhead, phalanx, or echelon type formation on the front, and a broader and more amorphous peloton extending far back, according to the width of the road and the race scenario.
Being in the center of a huge peloton is like being swept along, surrounded, while doing very little work. Some riders could go for hours without having to lead the group at all, so those sheltered people are never 'burning their matches' above a threshold level, nor the slow-burn on/off of the breakaway escapees. Glycogen reserve is limited
Is it just fresher legs or a size advantage - it's both, the larger and more cohesive the peloton is. In a mass-start event. The bad part is being 'boxed-in' - it's becoming a nervous affair when the speed is up, sometimes vague accidental jostling shoulder to shoulder within the group, I can't move straight forward because I will clip someone's rear wheel, and I can't move straight back, because I would cause, whomever is drafting me at the time, that same problem, and they may crash. A good position is: near the front (to avoid the risk of crashes further back) but not on the very-front (thus to avoid work). So in real racing (not amateur like me), teams want to position and protect their GC hopefuls or sprinters like that.
Teams pulling on the front are doing that: to control the pace when strategically they decide that faster / slower pace at that moment is more important than conserving energy for later. Escapees have no choice, relentless, and if they don't all cooperate efficiently as 'frenemies' then they are likely to be caught by the peloton

 

[Leinster]

Re:

I'd like to see a study comparing different sized groups. We've all seen small breakaways, say, 10-12 riders, get caught by the peloton. I guess the peloton is driven by fresher riders, but probably no more of them than alternate in the break. If there are two or three of them, the draft advantage would be greater, but the break could do the same thing.

So is it just the fresher legs, or a size advantage?

It doesn't happen as much, but you do sometimes see when a well-organized group of 8-10 riders, well-distributed among the teams, and only 1 team has any motivation to chase (say, nobody wants to help set up a sprint, if e.g. Bora or Quickstep have the only top-rank sprinter in the race) and the break stays away. It also happens in shorter stage races with smaller teams, where the chasing teams only have 6 riders, and they run out of manpower sooner.

In those cases, it is just a case of numbers. If a 10 rider group gets caught, it's because there were 3 or 4 teams in the peloton for whom catching the break was important enough to put more than 10 on the front.

 

[el_angliru]

I'm not sure we could consider this a scientific study but a German tv show for kids/youths did some tests with Ralf Grabsch in a velodrome. The show was called Kopfball, and this episode was aired 27th of March 2007, 11 AM. There used to be a video online of this episode until 4 or 5 years ago but there's no trace of it now.

They measured Ralf Grabsch's power output while he was riding at 45 km/h on the track under different circumstances. Here are the results:

Position Power (w)
Upright 520
Aero 434
Rider on his wheel 428
Behind a rider 282

434 w seems much for 45 km/h by today's standards but this was 2007 and I'm not sure how efficient Ralf's material was back then, and he probably wasn't the very elite of time trialists either (unlike his brother Bert)?

The intersting thing at the time was that one could save 1.5 % power by having a rider wheelsucking!

 

[cantpedal]

Re:



You wouldn't need to fly closely in front of a rider. First of all, you don't even have to fly "over" the road, you can fly next to it. Camera's will be much more stable than from a bike. Less vibrations and shakes, meaning you can fly farther ahead and zoom closer (which is a problem on a bike due to vibrations). For personal use, check DJI. They have really great quality drones under 1000$ with great image quality.


Camera drones are (just like a motorcycle) operated by two people. One pilotting the drone, one doing the camera. The main hurdles currently are the range of control and battery life. It's probably too soon yet, but technology progresses fast, especially once it hits mass production. Even 1000 dollar drones are used for professional TV reports. Image quality is actually very good, it will be more stable than shot from a motorbike. But i don't know the cost and specs of high-end drones. I know DJI has a pro camera drone (for television) for "only" +/-5000 dollars. Very stable and fast. But maybe there are even better drones for 5x that price, that have longer range and better battery. In theory, you could consider having a bus to operate the drones, riding 100 meters in front of the peloton, and swap batteries every 30 minutes, while staying close to the drone (for range). But i think it's still too soon. I guess they'll start on closed loop competitions first, and maybe start experimenting in 5 to 10 years. I 'm pretty sure they're being used on some CX races already since a few years.

But this is just my personal belief/opinion. I'm neither a drone expert, nor an aerodynamics expert.

You would think costs alone would drive this change. (Pilots, fuel, insurance, etc.)
I would imagine a mix of drones ant copters would do until the technology is proven in this application.

 

[Alex Simmons/RST]

The intersting thing at the time was that one could save 1.5 % power by having a rider wheelsucking!

This is a pretty well known phenomenon.

In this blog item I write about some impromptu aero experiments and talked about some other aerodynamics testing results that demonstrate the same thing:
https://wattmatters.blog/home/2015/08/when-your-ride-buddy-becomes-real-drag.html

 

[Logic-is-your-friend]

Great research. It makes you wonder how much influence motors have had on famous races in the past. Maybe they should use drones to film the race?

Re:
Is using drones really feasible?

I've been thinking about drones for cycling coverage before and in more detail again today after the topic came up again. Been looking at what's on the market currently for professional use. There are some interesting problems to solve for this to become feasible which I'd love to investigate in more detail.
Linking up with the topic of the thread, it would also be interesting to see the effects of a drone flying closely in front of a rider.

You would think costs alone would drive this change. (Pilots, fuel, insurance, etc.)
I would imagine a mix of drones ant copters would do until the technology is proven in this application.

https://www.facebook.com/video.php?v=733726620402423

View: https://www.facebook.com/tourdelavenircycliste/videos/733726620402423/

 

[Red Rick]

I think it's a lot harder to find people who can fly a drone remotely without crashing than people who can ride a camera motor

 

[Sestriere]

I think it's a lot harder to find people who can fly a drone remotely without crashing than people who can ride a camera motor

Yes, I think you will have to develop a system where the drones actually work autonomously. I imagine something where the director instructs the drone to shoot a specific group of riders from a specific distance/angle/whatever and the drone, by having the necessary sensors and a.i. onboard, maneuvers itself into the position to deliver the requested shot.

 

[Logic-is-your-friend]

I think it's a lot harder to find people who can fly a drone remotely without crashing than people who can ride a camera motor

I think this is an extremely silly statement.

As someone who got his motorcycle license aged 19, i can tell you there is a huge difference between "being able to ride a (motor)bike" and "riding a camera motor". As a camera motor, you need to be able to ride a massively heavy bike (these are never light bikes, and with good reason), with a cameraman as duo, who is carrying heavy gear, who is constantly maneuvering (sitting up, hanging left, hanging right...) at LOW speeds. Furthermore, you need to be very familiar with the peloton, how riders move, how the peloton flows, when to wait, when you can pass by... This is a VERY small pool of riders who can do both. Safely. Motorpilots from the VRT were hired by other channels not so long ago, to do worldchampionships, TDF etc... simply because it is such a niche.

Camera drones are also operated by a pilot and by a cameraman. They are stuffed with sensors to make sure they don't crash into stuff, safety features to go to certain altitude and keep hovering, in case connection is lost. You don't need to fly directly over the peloton (see the video above). About every production company now has a drone pilot. They don't need to fly "through" the peloton, so there are a lot of safety issues that simply do not apply.

 

[Red Rick]

I think this is an extremely silly statement.

As someone who got his motorcycle license aged 19, i can tell you there is a huge difference between "being able to ride a (motor)bike" and "riding a camera motor". As a camera motor, you need to be able to ride a massively heavy bike (these are never light bikes, and with good reason), with a cameraman as duo, who is carrying heavy gear, who is constantly maneuvering (sitting up, hanging left, hanging right...) at LOW speeds. Furthermore, you need to be very familiar with the peloton, how riders move, how the peloton flows, when to wait, when you can pass by... This is a VERY small pool of riders who can do both. Safely. Motorpilots from the VRT were hired by other channels not so long ago, to do worldchampionships, TDF etc... simply because it is such a niche.

Camera drones are also operated by a pilot and by a cameraman. They are stuffed with sensors to make sure they don't crash into stuff, safety features to go to certain altitude and keep hovering, in case connection is lost. You don't need to fly directly over the peloton (see the video above). About every production company now has a drone pilot. They don't need to fly "through" the peloton, so there are a lot of safety issues that simply do not apply.

Fact is the camera moto drivers are an established profession in the pro peloton.

I'm all for using drones. It's just that the sport is extremely resistant to change.

 

[Logic-is-your-friend]

Fact is the camera moto drivers are an established profession in the pro peloton.

I'm all for using drones. It's just that the sport is extremely resistant to change.

This may be true, and like i stated in previous posts, i don't see this changing in the next 5 or maybe 10 years either. But that is a completely different argument than the one you just made.

 

[Red Rick]

This may be true, and like i stated in previous posts, i don't see this changing in the next 5 or maybe 10 years either. But that is a completely different argument than the one you just made.

I'll rephrase.

They can't do it instantaneously, and cycling gonna cycling so making it happen will take faaaar too long.

 

[Logic-is-your-friend]

I agree with that. But i think they can do it gradually. Sports like cyclocross are ideal to start trying out (and they've been doing it there already). Races with local laps of a few km too. And mountain stages like the example above. Mountainbike downhill... Other sports will play their part in making drones a standard as well.

 

[Logic-is-your-friend]

Waiting for Tour Colombia, i decided to watch the 5th stage of San Juan 2020 again. The infamous stage where Evenepoel got caught in the second peloton and had to do a lot of work in order to get back, after the wind had caused echelons. Now, apparently, it wasn't crosswinds (they would use the entire width of the road were that the case) that caused the gap, it was wind coming from behind. Meaning, the guys pulling the group, had a lot less benefit than the guys in the back of the group... unless. Unless the guys in the front are literally being TOWED by 3 motorcycles. This wasn't motorpacing. This was next level savagery. Especially considering the speed, they were riding 70km/h, which means the advantage behind the motorcycles was huge.

I don't know how i didn't see this the first time but this *** goes on for miles (well over 10k). I'll let the images do the rest of the talking:

 

[Wvv]

I, for the sake of the entire Cyclingnews Forum, will draw the only right conclusion following Logic's post:

Evenepoel > motorcycle.




No, all kidding aside, that really looks like an abomination and shines another light onto the course of events of that particular stage. I already heared about it not being crosswinds that divided the peloton, so this connects with Logic's theory. It's a shame this could happen, but a relief that it didn't cause the strongest rider in the race to lose the overall victory.

 

[Logic-is-your-friend]

Regarding the inevitable evolution toward replacing camerabikes and/or choppers with drones... i honestly think this is a matter of years at this point. DJI has launched an agricultural drone for spraying crops. It carries a whopping 20L tank + a 7kg battery (larger than an electric bike battery). Combined the tank and battery outweigh my 9 year old daughter. That's a lot of weight to carry for a prosumer drone. Point being, that with today's light weight camera systems, it should already be feasible to build a drone that can carry enough battery for an entire broadcast (say 2 hours). Replace the 20L tank, with a 500gr camera, and aforementioned battery might already be able to power a drone for 2 hours.

 

[Red Rick]

Regarding the inevitable evolution toward replacing camerabikes and/or choppers with drones... i honestly think this is a matter of years at this point. DJI has launched an agricultural drone for spraying crops. It carries a whopping 20L tank + a 7kg battery (larger than an electric bike battery). Combined the tank and battery outweigh my 9 year old daughter. That's a lot of weight to carry for a prosumer drone. Point being, that with today's light weight camera systems, it should already be feasible to build a drone that can carry enough battery for an entire broadcast (say 2 hours). Replace the 20L tank, with a 500gr camera, and aforementioned battery might already be able to power a drone for 2 hours.

The one function it probably doesn't really replace is to get spectators to move aside though you could probably arm it with some light weaponry

 

[Logic-is-your-friend]

The one function it probably doesn't really replace is to get spectators to move aside though you could probably arm it with some light weaponry

lol. A taser. Or cattleprod!

 

[tobydawq]

The one function it probably doesn't really replace is to get spectators to move aside though you could probably arm it with some light weaponry

Maybe they could experiment with lightsaber technology, creating walls along the side of the road that will just slice everything that comes to contact with them to pieces.

That should keep the spectators at bay.

On the other hand, a downside would be a vast increase of fatalities and horrendous injuries from even minor crashes.

 

[andrew_s]

Regarding the inevitable evolution toward replacing camerabikes and/or choppers with drones... i honestly think this is a matter of years at this point.

Yes, years.

It's not really a matter of the capabilities of the drones themselves, but other practicalities.
If you want to replace TV camera bikes, you've got to replace all of them, all of the time

The main objection is this sort of thing:

View: https://www.youtube.com/watch?v=xeviAWB0i4Y
(drone nearly landing on Marcel Hirschi).

That's the reason why, in the UK at least, flying a drone over the peloton would be illegal, and that the drone operator has to remain in sight of his drone at all times (under a vehicle roof would be unlikely to qualify).
Where do you put the drone pilots?
If it's in an open top car, you're just replacing motos by cars, which, whilst they may largely avoid drafting, are going to cause even more problems with safety when they try to get past riders, or wait to be passed by riders.
Flying to one side of the road has the problem of roadside trees, which would constrain the drone to the road (to say nothing about the affect on the sight lines of the drone operators trying to remain in sight of their drones).

Drones at CX races (and MTB):
Those I've seen have, apart from pre-race course previews, been cable cams rather than drones - i.e. cameras suspended on a system of overhead cables, cable car fashion. The give away is that you get the same moving overhead shots every lap, and occasionally you can see the shadows of the system..

 

[Logic-is-your-friend]

Yes, years.

It's not really a matter of the capabilities of the drones themselves, but other practicalities.
If you want to replace TV camera bikes, you've got to replace all of them, all of the time

The main objection is this sort of thing:

View: https://www.youtube.com/watch?v=xeviAWB0i4Y
(drone nearly landing on Marcel Hirschi).

That's the reason why, in the UK at least, flying a drone over the peloton would be illegal, and that the drone operator has to remain in sight of his drone at all times (under a vehicle roof would be unlikely to qualify).
Where do you put the drone pilots?
If it's in an open top car, you're just replacing motos by cars, which, whilst they may largely avoid drafting, are going to cause even more problems with safety when they try to get past riders, or wait to be passed by riders.
Flying to one side of the road has the problem of roadside trees, which would constrain the drone to the road (to say nothing about the affect on the sight lines of the drone operators trying to remain in sight of their drones).

Drones at CX races (and MTB):
Those I've seen have, apart from pre-race course previews, been cable cams rather than drones - i.e. cameras suspended on a system of overhead cables, cable car fashion. The give away is that you get the same moving overhead shots every lap, and occasionally you can see the shadows of the system..

This particular example has been repeated ad nauseam. Where are the video's of motorcycles crashing into riders, because they'll be easier to find. Or that's not a problem?

In the Giro, in the final ITT, they used a drone, not a cable cam. And yes, the drone did the same section over and over again. They have been used in CX as well.

If they would contract a drone manufacturer, to make a drone specifically for these purposes, they could keep the weight down (well below 5kg), with a decent enough camera system (even most consumer drones already feature capable lightweight cameras) and battery autonomy. They could make this a sponsorship deal. Include soft padding and additional safety features on the drone, like safety guards and immediate halting of the propellers in case of any sudden altitude drop or impact (like hitting a branch). Have them feature a signaling sound/beep, to warn riders they are near.

Regulations for pilots could be very straight forward: No flying directly over people with a buffer of a certain number of meters horizontally and at limited speeds. Altitude no higher than 3 meters above ground (below street cables etc) unless in specific zones, and/or at least 100m removed from riders/spectators. If a drone comes crashing down first of all, it would be a from low height. In case of low weight as stated above, risk of direct injuries is minimal. Worst case, a soft padded, 4 kg drone drops 1.5 meters down onto a rider. I would prefer that over a motorcycle crashing into me.

A drone would need a pilot with front and back FPV and a separate camera operator for the broadcast footage. Not one person doing both. Just like camerabikes, pilots would need to be trained and pass specific exams. Just like camerabikes, certain arrangements have to be made with the cyclists. How, where and when to overtake if needed. Where possible, a drone could overtake riders next to the actual course, unlike bikes. They could use the bikelane, hover over a creek next to the road, the parkingspace... which is not possible for bikes. You could have one car/van with pilots 100m in front of the first riders, and one behind the peloton.

Obviously, this should be thought out, executed by capable people, while safety precausions are taken in every possible way. The video you posted, fails on all accounts. I'm not advocating amateur drone pilots using 500 euro drones from the local toy store and do whatever they please. They could gradually shift towards using drones. Easier to do in a race/section with lots of plains on both sides of the road, even ITTs. Build experience and knowhow. Or in mountain stages where drones could continuously fly next to the road. If anything, descents would be a lot safer without camerabikes.

 

[Red Rick]

This particular example has been repeated ad nauseam. Where are the video's of motorcycles crashing into riders, because they'll be easier to find. Or that's not a problem?

In the Giro, in the final ITT, they used a drone, not a cable cam. And yes, the drone did the same section over and over again. They have been used in CX as well.

If they would contract a drone manufacturer, to make a drone specifically for these purposes, they could keep the weight down (well below 5kg), with a decent enough camera system (even most consumer drones already feature capable lightweight cameras) and battery autonomy. They could make this a sponsorship deal. Include soft padding and additional safety features on the drone, like safety guards and immediate halting of the propellers in case of any sudden altitude drop or impact (like hitting a branch). Have them feature a signaling sound/beep, to warn riders they are near.

Regulations for pilots could be very straight forward: No flying directly over people with a buffer of a certain number of meters horizontally and at limited speeds. Altitude no higher than 3 meters above ground (below street cables etc) unless in specific zones, and/or at least 100m removed from riders/spectators. If a drone comes crashing down first of all, it would be a from low height. In case of low weight as stated above, risk of direct injuries is minimal. Worst case, a soft padded, 4 kg drone drops 1.5 meters down onto a rider. I would prefer that over a motorcycle crashing into me.

A drone would need a pilot with front and back FPV and a separate camera operator for the broadcast footage. Not one person doing both. Just like camerabikes, pilots would need to be trained and pass specific exams. Just like camerabikes, certain arrangements have to be made with the cyclists. How, where and when to overtake if needed. Where possible, a drone could overtake riders next to the actual course, unlike bikes. They could use the bikelane, hover over a creek next to the road, the parkingspace... which is not possible for bikes. You could have one car/van with pilots 100m in front of the first riders, and one behind the peloton.

Obviously, this should be thought out, executed by capable people, while safety precausions are taken in every possible way. The video you posted, fails on all accounts. I'm not advocating amateur drone pilots using 500 euro drones from the local toy store and do whatever they please. They could gradually shift towards using drones. Easier to do in a race/section with lots of plains on both sides of the road, even ITTs. Build experience and knowhow. Or in mountain stages where drones could continuously fly next to the road. If anything, descents would be a lot safer without camerabikes.

Yeah this sounds very reasonable. IMO just have risk/safety assessment, that's really important, other than that I don't see how there's any disadvantage.

Descents with drone footage should look amazing.