Bumpdrafting would work at NASCAR speeds, so it could be used there. But the aero forces at karting, R/C and even BTCC levels are simply not strong enough to allow bumpdrafting. The increase in speed either driver would get in those categories from it would be so miniscule that it just wouldn't work.
Let's just agree to disagree then
At least I know not to do it to you.Why would I go find you pictures of single seaters BD? I just told you it doesn't happen, and I've only ever seen the 2 idiots in the BMW World Series do it. But to say it's impossible is taking it to the other extreme, because it is possible... Just insane.
As for the Kyle Petty quote... At least you know why he's always hung out to dry on the speedways...
In fact most race series say to avoid car to car contact. For very good reason too. Apart from the obvious potential for malicious action there is a safety factor. These two things alone over-ride any logical argument for bump drafting as legitmate racecraft, even if they do provide an advantage to both cars when done correctly by practiced drivers. As has been mentioned above by others, in LFS there is an added danger of lag causing one or both cars to spin off and ruin everyone else's race.
You might enjoy it as a novelty way of running erroneous lap times, but in LFS in a race all deliberate contact should be avoided. For all you know, your antics are about to ruin someone's race. How can there be any further debate in light of this?
If you break it down, two bumpdrafters are teaming up with each other to provide an advantage over other cars not in a position to use the technique in order to produce lap times that would not be normally possible by any other skilled driver in a fast car. In many cases (as people have said in their posts here) there are instances where there is no agreement between two drivers, and one is about to get bumped by surprise, possibly to the peril of him and other cars nearby. Avoidable contact, avoidable conflict, avoidable accident. Where again is the argument in favour of bumpdrafting in LFS? If you refrain from bumpdrafting you won't be any worse off than all of the other racers who are sensibly avoiding contact, conflict and accidents and still fighting hand over fist lap after lap enjoying the racing as much as anybody else.
Please don't lag me into oblivion just because you think I could do with a little push.
I'm going to quit trying to prove my point...
Here's a vid of a KART on a long straight bumpdrafting another kart...
First a little nudge, and then when the lead car nods a long ass push (no that's NOT just running really really close) along the huge straightaway...
There is, in my book, absolutely nothing wrong with this kind of bumpdrafting in LFS...
(it's in 2 parts, because 1.95MB on the forum != 1.95MB in windows
)
Here's a vid of a KART on a long straight bumpdrafting another kart...
First a little nudge, and then when the lead car nods a long ass push (no that's NOT just running really really close) along the huge straightaway...
There is, in my book, absolutely nothing wrong with this kind of bumpdrafting in LFS...
(it's in 2 parts, because 1.95MB on the forum != 1.95MB in windows
)Can you share your definition of bump drafting? I just want to make sure we are talking about the samething here.
I had my first experience of bump drafting tonight, some guy just started pushing me from behind on the oval in the FO8, just touched 200mph and got my a very quick PB, he also managed to push me up to catch first place, although i did finish 2nd.
he crashed after a lap or so though
he crashed after a lap or so though
Then you don't understand lag. If you bump others unexpectedly then you don't care if they crash. It's just simple logic really, no opinion required.
^^ I'd call that on an oval, in a kart the speeds are much slower and small amounts of contact are part of the game.
How is it unexpected? I don't know about you but I watch how people are going to pass me, so I can setup a counter-attack. And if he isn't pulling out to pass, this can only mean two things, hes going to draft me, or bump me. I'll be prepared for either one.
Have you ever raced me? Because then you'd know your logic doesn't make much sense... I'm probably one of the nicest people on the track. Yes, I make my share of mistakes, but I don't go slamming doors shut that I leave open, nor try to push into holes that do not exist, like some of the aliens I've raced over the years. Why? Because I want the other drivers to finish the race as much as I want myself to.
I understand lag better than most people, since it makes a huge impact on who I'll bump, and who not (ever since NR 4). There's less spike lag in LFS than there was in NR2003S (sudden warping and stuff)... And we used to BD all the time there (ESCORS championships), and it went wrong about as often as it does in the real world (ok, bit more often, but not noticably much more). Out of experience, I can tell you that bumpdrafting is safe enough when you know who to do it with and who not to do it with.
The problem remains that there are too many people BD that have no clue when and how to do it.
Doesn't matter if it's on an oval or on a tight and twisty circuit like your local kart track... It's a kart, and it's BD, which you said never happened (actually, you didn't, Keiran did, but you agreed)... Do you really think other racers won't take that opportunity when it presents itself (like in BTCC)? There's 2 videos of bumpdrafting in non-NASCAR series in this thread (one RC, one kart), and still you keep saying it doesn't happen anywhere but NASCAR... How much proof do you need?
Sure.
Bumpdrafting (as in LFS, and as under discussion here [originally]) is when the following car is 'sucked' along by the lead car until the following cars speed (car 2) is greater than that of the lead car (car 1). So V1 < V2 (where V is velocity).
Now, car 2 uses his additional kinetic energy (0.5mv^2) to collide inelastically (but elastically in LFS I think) with car 1. This imparts an impulse upon car 1, which creates a positive change in car 1's momentum. This in turn increases car 1's kinetic energy and, therefore, speed.
Now V1 > V2, and V1ii > V1i.
Therefore Car 1 is travelling slightly faster than car 2, and a small gap opens up between the two. This gap creates a low pressure region (gauge pressure) between 1 and 2, which causes a slipstream/draft effect. The speed (and hence kinetic energy & momentum) of car 2 is increased due to this, causing the gap to decrease. When the gap equals zero, the same transfer of speed, momentum and energy (all the same thing really) is transferred from 2 to 1, causing an increase in speed, creating a gap, creating a draft. V1n > V1i and V2n > V2i. Ad infinitum (or until car 1 brakes because car 2 is driven by a conceited eejit).
Bumpdrafting is all about the draft. If the draft is not strong, then it cannot occur. The draft is not strong enough in karts, and as such it CANNOT occur. Anyone who mistakenly thinks that bumpdrafting exists in karts or R/C cars (or even BTCC) is mistaken and deluded. Car 2 in that instance could have more power, less drag, higher Tn-1 exit speed or some other advantage that causes him to bump car 1. It may be at a point on the circuit where passing is not possible, but car 2 wants to retain as much speed as possible - he can do this by sacrificing some of his speed to car 1 and thus they both travel quicker. It is not, until speeds reach much over 130mph in my estimation, that bumpdrafting (i.e. with a draft or slipstream) could actually provide any worthwhile speed benefit.
Having said that, I will still brake if someone tries it with me. And don't say I'm mean or wrong for doing that - cos now I've warned you all, and you can't blame me when you forget I said it
Tristan, you forget one thing... Aerodynamically designed vehicles create less of a slipstream than the touring car type cars which aren't... So a formula 1 type car would create a hole about 1 meter long, while a BTCC car would create a hole about 10 meters long. So while an F1 car may have a draft at 130mph, a BTCC car may have a draft at 100km/h.
Tell me what a "worthwhile speed benefit" is, if you would be so kind...
As for it not existing in R/C cars or karts... Watch the vids, and read this quote from a TransAm driver:
Why would he mention Bumpdrafting when it doesn't happen?
(I won't forget not to bumpdraft you)
Tell me what a "worthwhile speed benefit" is, if you would be so kind...
As for it not existing in R/C cars or karts... Watch the vids, and read this quote from a TransAm driver:
Why would he mention Bumpdrafting when it doesn't happen?
(I won't forget not to bumpdraft you)
TransAm is a bit quicker than BTCC, so I fully agree that bumpdrafting is technically possible in that series, and others of similar speed.
I watched the karting vid already thanks, and it doesn't look to me like bumpdrafting. Bumping, sure, but not because of or aided by a draft. What karts are they, and how fast are they going.
As for the R/C vid, I couldn't see it in my quick scan of this thread 3 pages (50 posts per page). There was one rapidshare link with no description (something about Formula cars I think), but I didn't download it. And I'd still stick to my theory that it wouldn't be a draft that caused the bump, but just a higher speed for whatever reason.
But still, regardless of whether is technically achievable, or whether certain real 'racers' use the technique, it should be avoided in the vast majority of motorsport in my opinion. I can't force my opinion down your throat, so on this matter I will have to disagree with you. You think it's acceptable, I do not. Ever. I'm just pointing out the physcial reasons why certain classes couldn't use it.
As for reasonable gains - thats a matter of opinion ultimately. I'd have though that gaining half a mile per hour for half a second isn't worth the risk (of performance limiting damage, or a crash), or the lack of situational awareness (you're concentrating on not causing a crash, and so miss your braking point). For example - watch the kart driver. He forgets where he is and goes too far right, loses speed, never catches up, and is further behind after the straight than he was at the start. Great advantage he enjoyed.
Edit: Stu Hayner (whoever he is) might be wrong? Lots of race drivers aren't clever people (just ask Caroll Smith). He could have heard the term from someone and thought it was gospel. Just because an unheard of (world-wide speaking) driver claims something is real doesn't mean it is (in the same way that if someone proves my above physics lesson wrong I am willing to accept that). I could state that all lemons are in fact whales, and that being a monkey means I must know. But it doesn't make it fact (I chose the objects at random there, did you notice).
I watched the karting vid already thanks, and it doesn't look to me like bumpdrafting. Bumping, sure, but not because of or aided by a draft. What karts are they, and how fast are they going.
As for the R/C vid, I couldn't see it in my quick scan of this thread 3 pages (50 posts per page). There was one rapidshare link with no description (something about Formula cars I think), but I didn't download it. And I'd still stick to my theory that it wouldn't be a draft that caused the bump, but just a higher speed for whatever reason.
But still, regardless of whether is technically achievable, or whether certain real 'racers' use the technique, it should be avoided in the vast majority of motorsport in my opinion. I can't force my opinion down your throat, so on this matter I will have to disagree with you. You think it's acceptable, I do not. Ever. I'm just pointing out the physcial reasons why certain classes couldn't use it.
As for reasonable gains - thats a matter of opinion ultimately. I'd have though that gaining half a mile per hour for half a second isn't worth the risk (of performance limiting damage, or a crash), or the lack of situational awareness (you're concentrating on not causing a crash, and so miss your braking point). For example - watch the kart driver. He forgets where he is and goes too far right, loses speed, never catches up, and is further behind after the straight than he was at the start. Great advantage he enjoyed.
Edit: Stu Hayner (whoever he is) might be wrong? Lots of race drivers aren't clever people (just ask Caroll Smith). He could have heard the term from someone and thought it was gospel. Just because an unheard of (world-wide speaking) driver claims something is real doesn't mean it is (in the same way that if someone proves my above physics lesson wrong I am willing to accept that). I could state that all lemons are in fact whales, and that being a monkey means I must know. But it doesn't make it fact (I chose the objects at random there, did you notice).
Not sure what your on about with karting but over here when I raced karts I was pulled up to the clerk of the course for tapping the back of another kart because he was having trouble acclerating and it caught me out. He never got knocked off the track or anything. The clerk of the course told me off saying that basically that I shouldn't have made so much contact with the kart in front. Even though it was only a small tap because I was trying to stay on the thorttle to out acclerate him down the stright the clerk told me off. It is foolish to do it delibreately. I've been unlucky enough to have a massive engine blow up while doing about 50mph and having someone ram up the rear of me. The force of him hitting me caused me to spin round and round ending up right in the middle of the track in front of a pack of 10 odd karts
Had he been bumping me up the rear like you say people do in comeptive racing it could have caused a far bigger accident.The main reason contact has to be avoided in motorsport is for safety. I've watched and taken part in big Scottish karting events and no one bumped into each other. If there was bump drafting in karting we would have to replace our rear number plates and brackets every race
illepallAlso for the R/C bump drafting thing you have to be joking me. I've been lucky enough to have raced in the same events as some of the worlds best in 1/10th electric touring cars and they never even touched each other. They would run close but they would never run into each other. A great site to watch a grid of 10 of the worlds best race hard and fairly
Keiran
Lol, it isn't my logic. Like I said, opinions are irrelevant in light of the facts, even mine.
Point 1: We know already that cars with a higher latency will appear to jump around in relation to your car. We know that odd collisions often occur in these cases and they are best avoided.
Point 2: We know that many people consider a bump from behind to be disruptive and would prefer no interference. We also know that some racers will take offense to this and act according to their interpretation the action with unpredictable outcomes for all.
Point 3: We know that in the majority of real life race series that deliberate contact is illegal or of questionable ethics and so is frowned upon.
These three points have nothing to do with my or your opinion. A logical process of deduction after considering these points leads me to suggest:
a: A real potential exists for disruption or accidents during and after a driver takes it upon himself to bumpdraft, whether the leading car is expecting it or not.
b: A real potential exists for conflict and animosity between drivers due to these actions, even if no accident or apparent disruption occurs.
c: Bumpdrafting, or any deliberate contact is not at all common or accepted in the greater world of motor racing, with very few exceptions (some of which seem to be in conflict with themselves and with popular opinion).
Weighing up these points and deductions, even with a healthy dose of scepticism, one can arrive at the conclusion that bumpdrafting in LFS is a risky venture which may cause accidents, fights and general on-track mayhem.
I could harp-on on the poor structural integrity of formula car aerodynamic devices, and how an F1 car disturbs the air for up to 100metres behind it as it races along, that the hole it punches in the air is way more then one metre and how oval racing is not by any means a universal example of motor racing behaviour and regulations, but I don't need to because the logical conclusions arrived at previously negate the need for such elaboration. So my actual opinion is irrelevant. The facts tell me what I need to know, whether I choose to accept it or not.
Okay, one thing still is bugging me from that explaination. If karts can't produce that strong of a draft to allow for bump drafting from any distance, then how is drafting a bicycle and another human possible?
http://www.aerospaceweb.org/qu ... /aerodynamics/q0092.shtml
If a human body can give off a slipstream to allow for drafting, why can't the exposed human body in a kart give off that same effect?
Thats a good question, and the sign of a good discussion. However, I am going to bed now, and I will think about it overnight and tomorrow before I reply.
the answer to your question is already given in the text you quoted. On a bicycle the draft is not used to gain speed (as tristancliffe explained) but for reducing the energy needed to maintain a given speed.
If you ever drove with a bicycle (and i'm sure you did) then you will have felt air resistance which you have to work against. Someone who is following you closely will have less air resistance hence he needs less energy to go your speed and will probably be less tired after arrival.
Professional bicycle teams who drive tour de france usually consist of one top driver and 5 or 6 "helpers", who are just there to lower the air resistance for their top driver letting him draft as long as they can. They are basically sacrificed in the process because they have used up all their energy long before the race ends.
Yes but you are missing the point, If they can draft, so can karts. But for karts, it's not to lower the energy required to stay at that speed, it's to raise the speed and use the same amount of energy.
tristancliffe didn't say that karts cannot draft, he said it has no big effect. That is because the overall top speed of karts is low and probably because kart tracks usually don't have very long straights so the result is not really worth it.
If you had to produce the energy of the kart with your feet, then it would have a huge effect of course
Thats what I wanted to say, both cases are not really comparable.Which I already said I do avoid.. I don't go around bumping every car on the track.
That's not the problem of the bumper, but a lack of discipline of the bumpee... So if someone messes up an overtaking manouvre, and pushes me to the outside of the track, that gives me the right to punt him off in retaliation on the next turn?
And that's why there are rulebooks... And if the rulebooks say "no bumpdrafting" then I shall not bumpdraft... No such rulebook exists in LFS, only in the leagues. So in public servers, it's allowed unless otherwise stated. Frowned upon or not. Besides, it's really fun when you find someone you can work with race after race... So what's the big issue? It's all in good fun. Don't agree with BD, let me know, and I might just stop doing it just for you.
Very good points, but not only valid for BD. Forget point C and replace BD with overtaking. Same conclusion. So is overtaking bad? Has nothing to do with BD in itself, but more with the amount of stupid people on servers. Like I said before, there's no harm in BD when done correctly, and when both drivers are in agreement.
As for point C, LFS doesn't represent the "greater world of motor racing", LFS represents "all of motor racing", which includes the part that does think BD is ok. It IS a part of motor racing, and as such it will be done in LFS... Nothing anybody can do about it in public servers with no set rulebook.
Yes, and could make for some really fun races too.
Disturbing the air, yes, but the vacuum a formula car makes is very small because of the way the air flows around it (1 meter was just exaggerated to show the point, but not far from the truth, watch the spray of rain behind a formula car, it goes straight up... the vacuum (draft) is where there's no spray). Dirty air is not a draft or slipstream. Slipstream is the hole a car creates in the air, sucking the next car towards it. A formula car is designed NOT to do that.
But the facts as you represent them are open for interpretation. It's like religion. Everything is presented as being facts, but the only fact is that it is only an opinion on how to interpret the so-called facts that is presented as fact.
The only difference is the source of energy... So both cases are pretty much the same. Aerodynamics don't change.
No they aren't open for interpretation. No it isn't like religion at all. No this is not an opinion.
What on earth are you on about Vacuums. There won't be a vacuum. To get a draft all you need is a situation where the air pressure following a car is lower than the air pressure not following a car.
In an F1 car the air is thrown about, directed upward, eddy currents and vorticies are set up and what have you. All of this helps to create a lower pressure region behind the car.
What the F1 designers try to do is reduce this pressure drop (which they can't do completely), and increase the rate at which the low pressure region recovers - thus not allowing the following car to gain a draft. Add in to that that modern F1 cars are designed to work 'best' in clean, predictable air (like a CFD program can cope with), but loses efficiency in 'dirty', turbulent air, and you have a recipe for low draft, low overtaking situations.
Spouting nonsense about the air going upwards and therefore not creating a vacuum just makes you look silly. And if you look silly, your chances of convincing us that bumpdrafting is used to any great extent in real life are greatly diminshed.
Now, about the bicycle. It's already been mentioned that the karts, bikes, R/C cars etc all generate low pressure regions behind them, and therefore slipstreams. It's a nature of objects travelling through fluids.
But a bicycle is powered by the legs. Legs get tired - engines don't. Any energy saved by slipstreaming will save the legs of that slipstreamer to give him a later advantage.The same occurs in NASCAR. NOT being the lead driver, I believe, can save you quite a lot of fuel being sucked along.
Now, if a bicycle tried to bumpdraft there would be a crash. But also the gain in speed isn't that much - it's more about saving energy, which is the square of speed. A kart isn't trying to save energy (except perhaps in an endurance race, like all cars), but trying to maximise it's speed. But the little gains of speed a draft are likely to have been mostly lost in the inelastic collision when two karts touch. R/C cars - I can imagine the body squashes and aborbs the energy rather than channel it purely into the velocity of the lead car.
*breathes out*
Bumpdrafting
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