At first you said it's all about Ackerman... and now you say that in drifting you need paralel wheels in full lock (so no Ackermann geometry at all) And then you bring all these other aspects that indeed have a great effect on car's behaviour but do not necessarily make it unstable or hard to drive.
So this sould be an easy one for you.
Does any of thiese mods eliminate Ackerman geometry?
http://kpi.squarespace.com/steering-angle-modifications/
I still think you have a very limited understanding of what you are talking about but I am not going to bother with this anymore.
Ok ok I get it. No more talking to you Mister "engineer".
So this sould be an easy one for you.
Does any of thiese mods eliminate Ackerman geometry?
http://kpi.squarespace.com/steering-angle-modifications/
I still think you have a very limited understanding of what you are talking about but I am not going to bother with this anymore.
Ok ok I get it. No more talking to you Mister "engineer".
Where exactly in the "page of Ackermann" did you read this?
"The car in video can do only drift"
Not at all. A drift car is not neseserily an usntrable car... Ackermann geometry defines the relative difference in angles between the front two wheels according to steer radius, wheel track and wheelbase of the car. It does not determine the maximum steering angle of the wheels... let alone making the car unstable...
I didn't want to insult anyone but you are asking for it.
Stop talking about things you can barely understand.
It's the same run... You just get a different perseption from different camera angles. Only in corner entry and the first half of the corner he is holding a drift angle above 90degrees. As he powers out of the corner, he reduces the drift angle to what front wheels can cope with.
And how exactly you know in what speed Tiff's drifts are? Because he says "and here I am. ballancing in a hundred miles/hour blah blah"? He is a tv show presenter... he is supposed to exagerate in his coments to make it even more thrilling to whach.
And how exactly you know in what speed Tiff's drifts are? Because he says "and here I am. ballancing in a hundred miles/hour blah blah"? He is a tv show presenter... he is supposed to exagerate in his coments to make it even more thrilling to whach.
Last edited by kaynd, .
Well 36degrees is the steering angle for both wheels in 100% parallel steering.
eg in XRT setting the parallel steering to 0, implementing full Ackerman Geometry, the leading wheel has 43+ degrees angle and the trailing wheel ~30 degrees.
It’s still more than what most sport cars have in stock.
http://kpi.squarespace.com/steering-angle-modifications/
Looks like taking account Silvia S14 service manual page 449 or FA-15 , that S14 has similar leading wheel turning angle with XRT. Leading wheel 39-43degrees and trailing wheel 33degrees.
You need a drift purpose steering modification to have 52+degrees at the leading wheel in order to atchieve what we see in the video above.
It's not in our hands.
It's the developers choice.
For me drifting is enjoyable and challenging as it is with current steering angles.
And it is a lot more chalenging with low steering angles in general.
As for the drift vs race debade. Well it's meaningless and for sure It's not covered in simplistic examples.
There is not an objective way to mesure how big or small a mistake is in different sports. From what I have experienced a "small" mistake can put you out of races too. And from my prespective it's much easyer to cover your mistake while you are always sliding at an angle. But all this is nonesence... what makes it hard is the competition. It's a matter of how competitive your oponent/s is/are.
eg in XRT setting the parallel steering to 0, implementing full Ackerman Geometry, the leading wheel has 43+ degrees angle and the trailing wheel ~30 degrees.
It’s still more than what most sport cars have in stock.
http://kpi.squarespace.com/steering-angle-modifications/
Looks like taking account Silvia S14 service manual page 449 or FA-15 , that S14 has similar leading wheel turning angle with XRT. Leading wheel 39-43degrees and trailing wheel 33degrees.
You need a drift purpose steering modification to have 52+degrees at the leading wheel in order to atchieve what we see in the video above.
It's not in our hands.
It's the developers choice.For me drifting is enjoyable and challenging as it is with current steering angles.
And it is a lot more chalenging with low steering angles in general.
As for the drift vs race debade. Well it's meaningless and for sure It's not covered in simplistic examples.
There is not an objective way to mesure how big or small a mistake is in different sports. From what I have experienced a "small" mistake can put you out of races too. And from my prespective it's much easyer to cover your mistake while you are always sliding at an angle. But all this is nonesence... what makes it hard is the competition. It's a matter of how competitive your oponent/s is/are.
Last edited by kaynd, .
Well it’s in typical high Big time Quality 
I have seen all your previous movies but haven’t commented because I got bored to congratulate you after your first 5or so good movies.
All I would like to add, even if it is just my subjective view. I would prefer a bit more FOV and angle (not in roll) variation. EG all 8 shots from 0:12 to :17 seem to have similar FOV and in many of them the car seems to cover the same space in the frame.
Same goes with the next 10 shots from 0:18 to 0:40.
No. they don’t look all the same, but many of them seem to be similar. Now this isn’t wrong. It’s just something that gets too profound in fast pace movies like yours when shots change in less than a second.
I have seen all your previous movies but haven’t commented because I got bored to congratulate you after your first 5or so good movies.
All I would like to add, even if it is just my subjective view. I would prefer a bit more FOV and angle (not in roll) variation. EG all 8 shots from 0:12 to :17 seem to have similar FOV and in many of them the car seems to cover the same space in the frame.
Same goes with the next 10 shots from 0:18 to 0:40.
No. they don’t look all the same, but many of them seem to be similar. Now this isn’t wrong. It’s just something that gets too profound in fast pace movies like yours when shots change in less than a second.
Impressive, especially after that tire pop!
(Your audio could be in a bit lower level. It’s distorting and tried to get me def after having forgotten my speakers in a bit higher volume than usual.)
(Your audio could be in a bit lower level. It’s distorting and tried to get me def after having forgotten my speakers in a bit higher volume than usual.)
Well I tried and watched the whole video. It is boring because it’s all about the “look I can drift” thing.
From the drifting perspective: You can hold a drift angle for long enough which is pretty easy in current LFS physics, especially in FZ5. But that’s it. Lines are kind of random and especially corner exits (you are supposed to straighten the car as you reach corner exit if you don’t have to hold another line for the next corner.)
As for the video:
I can see some interesting custom cameras but they are all with that huge FOV. The car should cover a significant amount of our screen in order to see it. A camera that has enough FOV to cover everything you want to show us in a single shot is not a solution here, unless your point is to show us the track and not the car action.
If you make another video, try and use the camera in a more effective way.
Music and basic effects are not so hard to implement. Just don’t start throwing around random effects or fast pace music with slow video action.
As for quality, try to stay in 32bits and use as low resolution as it needs to run so you can record. It may look awful in your screen but for a video even 640*480 is enough.
From the drifting perspective: You can hold a drift angle for long enough which is pretty easy in current LFS physics, especially in FZ5. But that’s it. Lines are kind of random and especially corner exits (you are supposed to straighten the car as you reach corner exit if you don’t have to hold another line for the next corner.)
As for the video:
I can see some interesting custom cameras but they are all with that huge FOV. The car should cover a significant amount of our screen in order to see it. A camera that has enough FOV to cover everything you want to show us in a single shot is not a solution here, unless your point is to show us the track and not the car action.
If you make another video, try and use the camera in a more effective way.
Music and basic effects are not so hard to implement. Just don’t start throwing around random effects or fast pace music with slow video action.
As for quality, try to stay in 32bits and use as low resolution as it needs to run so you can record. It may look awful in your screen but for a video even 640*480 is enough.
Yes that’s why I clearly state in my previous post that {nothing is a straight line here like “the more the better” or “the less the better” }.
Going full throttle at low rpm is comparable inefficient to going with too low throttle at high rpm. (By “throttle” I mean the pedal control of the car. Recent advanced engine management systems try to hold the electronically controlled butterfly valve as open as possible, trying to alter engine load by fuel mixture, ignition timing and valve lift-timing)
Last edited by kaynd, .
Theoretically this shouldn’t be the way for an engine to work efficiently. (I understand you might know all these but this post is not just an answer to you)
More revs and less throttle increase energy consumption cause of pump loses. Internal combustion engines basically work like air pumps. Keeping the intake restricted while revs build up just increases the energy that pump needs in order to turn.
Ideally you’d want to run an engine with no "butterfly" resisting air flow at the intake, adjusting fuel mixture in order to modulate power output.
But this is not always possible because lean mixtures (a little fuel - a lot of air) tend to either not combust at all or combust too violently in a way that no engine can handle it.
The "violence" of air-fuel combustion depends on many aspects but mainly in temperature, pressure and mixture distribution existing in the combustion chamber.
Fuel management systems take account all these aspects and provide the proper air fuel ratio. Lean enough fuel mixtures for cruising speeds in mid rpm in part throttle operation, and rich enough mixtures for safely produced maximum power-torque in the whole rpm range at full throttle.
Because the engine works like a pump, by restricting air supply intake, vacuum increases and so combustion chamber pressure decreases.
The less combustion chamber pressure - the less prone fuel mixture is to combust "violently". But also the more like to not combust at all
(So nothing is a straight line here like “the more the better” or “the less the better”…)
Fuel management system is programmed to go as lean as possible in part throttle operation and that justifies the lower fuel consumption while keeping the intake restricted even in an inefficient way like the butterfly valve.
Id say keep the lower rpm that allow you to accelerate lively by not using more than 50% throttle.
Same goes with cruising. Keep the lower possible rpm that allow you to use low throttle (arround 20%) in order to maintain your speed.
But really this depends on your car's fuel management mapping and the air induction technology it uses.
Speaking about less that 1000rpm difference between gears:
Definitely the gear that allows you to travel with noticeably less throttle will let your fuel management system use less fuel.
If the difference in throttle position is not noticeable I’d say stick with lower rpm.
Indeed it works with VLC.
someone else might find this post useful
someone else might find this post useful
Video stream sheems to play like a slideshow for me. I get one new frame every 10 seconds. Sound though is normal so I think that this hasn't to do with my connection.
Liked it a lot Starting scenes are great!
You have to practice a bit more in using some different or more appropriate camera angles to what you want to show.
eg from 1.52 to 2.08. You could have split this action shot to more than one phase, using different camera positions. It looks too long and kind of boring as it is now. Τhe flash effect doesn’t help much there. Same goes with 2.12, 2.20 where the camera could initially be closer to the car and then start to move backwards as the subject gets closer.
I think you already have the skill to take some really good shots. I sense that you got a bit bored filming the final shots of the movie and you didn’t pay as much attention as you did in the beginning.
Try to be more consistent and don’t get overconfident by the good comments you might have for this video.
Starting scenes are great! You have to practice a bit more in using some different or more appropriate camera angles to what you want to show.
eg from 1.52 to 2.08. You could have split this action shot to more than one phase, using different camera positions. It looks too long and kind of boring as it is now. Τhe flash effect doesn’t help much there. Same goes with 2.12, 2.20 where the camera could initially be closer to the car and then start to move backwards as the subject gets closer.
I think you already have the skill to take some really good shots. I sense that you got a bit bored filming the final shots of the movie and you didn’t pay as much attention as you did in the beginning.
Try to be more consistent and don’t get overconfident by the good comments you might have for this video.
indeed. I just focused at the end result of any limited slip differential.
Anyway still even a clutch pack LSD or any torque sensitive LSD is not about keeping equal torque in both wheels.
The point is always to distribute the torque towards the tire that has more traction. LSD is not about sending equal torque to each wheel. Its about limiting the angular velocity differences between the, two driven by the diff, wheels.
While I can understand roughly how method A applies, I can't understand at all method B. (talking about open diff)
Are you sure that method B works? What in this method indicates that both left and right output torques are equal at all times? Method B seems to fit better in a locked diff simulation.
Are you sure that method B works? What in this method indicates that both left and right output torques are equal at all times? Method B seems to fit better in a locked diff simulation.
Jeezz… for anyone posting how stuff work or simplistic general idea videos. Of course Bob knows in general how open diff works.
Title states clearly that he is seeking a solution from the mathematic point of view.
In locked diff both wheels rotate at the same speed but not necessarily both wheels transfer the same amount of torque to the ground. If it’s a traction limited case then the wheel that has more traction delivers grater torque to the ground. If both wheels have sufficient traction, then the torque delivery of each wheel depends on the relative distance each wheel rolling to in the same amount of time. Because both wheels have the same angular velocity, if they are not following the same tracks (eg in a turn) they deliver different amount of torque to the ground at the same time.
Anyway this is an example of useless information in this thread. I might be able to understand how a diff works but that doesn’t mean I can explain that in mathematic formulas.
I just want to add a +1 to that.
As an answer to “where the other XX amount of torque goes” It isn’t going any ware. Any engine provides at a given rotation speed as much torque as it’s asked to give. Till a point when the engine reaches it’s maximum torque delivery limit. (Common sense. I just write it down so the middle sentence doesn’t look illogical.)
So stop worrying about it and start working on the important stuff. (how power-angular velocity is transmitted between the two wheels.)
Now adding some general thoughts, I hope will help as a methodology in trying to solve this problem.
Generally we know that given specific circumstances a certain amount of torque is needed to overcome the traction of the less loaded wheel. While this happens we know that, speaking about an ideal diff with no internal friction, at both wheels is applied the same torque, limited from the wheel that is using the most power. (the one spinning in a greater speed).
If you know how much torque is needed to overcome the friction of the more likely to break traction wheel, you can calculate the power it uses each moment to increase it’s angular velocity, overcoming any friction and angular inertia. Then you know the torque applied to the other wheel and can calculate the power that is delivered to it. (if any in case it doesn’t rotate at all).
So the required power for this to happen is the sum of the power delivered to both wheels.
Then you can calculate the specific amount of torque that is transferred from the engine to the diff.
Using power because that way you don’t need to know the relation between the “planet” gears and the gears attached to the axels in order to calculate the specific amount of torque delivered from the pinion gear to the crown wheel, when a wheel is spinning faster than the other and final gear ratio has nothing to do with it anymore…
(a bit exaggerating by saying "nothing" but it is almost nothing if you don't know the relation between all gears in the diff when wheels are rotating in different speed.)
I am trying hard to make any sense.
Title states clearly that he is seeking a solution from the mathematic point of view.
In locked diff both wheels rotate at the same speed but not necessarily both wheels transfer the same amount of torque to the ground. If it’s a traction limited case then the wheel that has more traction delivers grater torque to the ground. If both wheels have sufficient traction, then the torque delivery of each wheel depends on the relative distance each wheel rolling to in the same amount of time. Because both wheels have the same angular velocity, if they are not following the same tracks (eg in a turn) they deliver different amount of torque to the ground at the same time.
Anyway this is an example of useless information in this thread. I might be able to understand how a diff works but that doesn’t mean I can explain that in mathematic formulas.
I just want to add a +1 to that.
As an answer to “where the other XX amount of torque goes” It isn’t going any ware. Any engine provides at a given rotation speed as much torque as it’s asked to give. Till a point when the engine reaches it’s maximum torque delivery limit. (Common sense. I just write it down so the middle sentence doesn’t look illogical.)
So stop worrying about it and start working on the important stuff. (how power-angular velocity is transmitted between the two wheels.)
Now adding some general thoughts, I hope will help as a methodology in trying to solve this problem.
Generally we know that given specific circumstances a certain amount of torque is needed to overcome the traction of the less loaded wheel. While this happens we know that, speaking about an ideal diff with no internal friction, at both wheels is applied the same torque, limited from the wheel that is using the most power. (the one spinning in a greater speed).
If you know how much torque is needed to overcome the friction of the more likely to break traction wheel, you can calculate the power it uses each moment to increase it’s angular velocity, overcoming any friction and angular inertia. Then you know the torque applied to the other wheel and can calculate the power that is delivered to it. (if any in case it doesn’t rotate at all).
So the required power for this to happen is the sum of the power delivered to both wheels.
Then you can calculate the specific amount of torque that is transferred from the engine to the diff.
Using power because that way you don’t need to know the relation between the “planet” gears and the gears attached to the axels in order to calculate the specific amount of torque delivered from the pinion gear to the crown wheel, when a wheel is spinning faster than the other and final gear ratio has nothing to do with it anymore…
(a bit exaggerating by saying "nothing" but it is almost nothing if you don't know the relation between all gears in the diff when wheels are rotating in different speed.)
I am trying hard to make any sense.
Last edited by kaynd, .
It’s not possible for you to be the first one to turn on the engine.
Engine has already run in the factory for a specific amount of time and in specific conditions. It’s an essential part of the quality control procedure of any product like this.
Now as for the distance driven from the factory to your dealership, and to you as a customer. This is something you should ask your dealer about.
Anyway you shouldn’t worry that much about this. A double digit number of driven km would hardly make any difference to your engine’s lifespan.
Your piston rings will have enaugh amount of time to seal under your own driving.
Engine has already run in the factory for a specific amount of time and in specific conditions. It’s an essential part of the quality control procedure of any product like this.
Now as for the distance driven from the factory to your dealership, and to you as a customer. This is something you should ask your dealer about.
Anyway you shouldn’t worry that much about this. A double digit number of driven km would hardly make any difference to your engine’s lifespan.
Your piston rings will have enaugh amount of time to seal under your own driving.
There are many idiotic drivers out there. But keep in mind that there is no way you can “give a lesson” to any of them.
Most of the times you can’t do it even even if you try doing it in a polite manner… let alone insulting…
Turning around to ask WTF is the wrong thing to do in situations like that.
The best that can happen, is scaring a driver who might accidentally didn’t pay much attention at his car’s blind spots. Many people respond to fear by doing foolish things. This could be dangerous…
Many bickers don’t understand that because most bikes have superior acceleration comparing to cars, sometimes they move unpredictably fast so car drivers are not always able to predict their position. This might not be relevant with your case but it is something you must have in mind when approaching another vehicles.
Now considering the worst case scenario, by chasing someone who did something criminally dangerous seconds before, you run the risk meeting a… lets say mentally ill person or some kind of mean person you don’t know how exactly is going to react.
This is dangerous.
Protect yourself by trying to predict other vehicles moves. Be predictable
Avoid as much as possible moving side by side with any car, or passing it close while moving at much higher speed.
Learn to control your anger.
Most of the times you can’t do it even even if you try doing it in a polite manner… let alone insulting…
Turning around to ask WTF is the wrong thing to do in situations like that.
The best that can happen, is scaring a driver who might accidentally didn’t pay much attention at his car’s blind spots. Many people respond to fear by doing foolish things. This could be dangerous…
Many bickers don’t understand that because most bikes have superior acceleration comparing to cars, sometimes they move unpredictably fast so car drivers are not always able to predict their position. This might not be relevant with your case but it is something you must have in mind when approaching another vehicles.
Now considering the worst case scenario, by chasing someone who did something criminally dangerous seconds before, you run the risk meeting a… lets say mentally ill person or some kind of mean person you don’t know how exactly is going to react.
This is dangerous.
Protect yourself by trying to predict other vehicles moves. Be predictable
Avoid as much as possible moving side by side with any car, or passing it close while moving at much higher speed.
Learn to control your anger.
update about GVRteam
The folowing drivers are no longer GVRteam members.
G.Alamaras [CBR929] GRC
A.Perrs [Varwnos] GRC
K.Daskalopoulos [kaynd] GRC
S.Papakonstantinou [mpakakas] GRC
B.Halaris [scoupegt] GRC
GVRteam’s responsibility is handed entirely to migf1 sinse 28/8/2009
I am no longer GVRteam's official or member.
The folowing drivers are no longer GVRteam members.
G.Alamaras [CBR929] GRC
A.Perrs [Varwnos] GRC
K.Daskalopoulos [kaynd] GRC
S.Papakonstantinou [mpakakas] GRC
B.Halaris [scoupegt] GRC
GVRteam’s responsibility is handed entirely to migf1 sinse 28/8/2009
I am no longer GVRteam's official or member.
Well. I love seeing tires working but even I, found this video a bit boring 
I think you have already done way better vids than this. (I have kept them at my hard drive) eg “who cares”
One rule of thumb for me. If it’s going to be in slow motion, it has to be silk smooth, especially when the whole movie is in slow motion at exactly the same pace.
Scenes seem to be repeated even thought they aren’t. That’s because of cameras with similar positioning and FOV are used again and again.
Well anyway I see some nice driving there and I can sense the artistic mood but that’s because I can imagine a lot of things that this movie didn’t show me.
I think you have already done way better vids than this. (I have kept them at my hard drive) eg “who cares”
One rule of thumb for me. If it’s going to be in slow motion, it has to be silk smooth, especially when the whole movie is in slow motion at exactly the same pace.
Scenes seem to be repeated even thought they aren’t. That’s because of cameras with similar positioning and FOV are used again and again.
Well anyway I see some nice driving there and I can sense the artistic mood but that’s because I can imagine a lot of things that this movie didn’t show me.
and another curb rollover crash
http://www.youtube.com/watch?v ... &feature=channel_page
This is a nice video archive to refer to every time someone claims that flipping a car, because of inside tires climbing a curb, is unrealistic.
http://www.youtube.com/watch?v ... &feature=channel_page
This is a nice video archive to refer to every time someone claims that flipping a car, because of inside tires climbing a curb, is unrealistic.
This isn't going to happen in any sim anytime soon... such a physics model, specialized only for the engine is extremely complicated.
"Drown by hand" power cuerves, imitating or copying similar power curves from similar real engines, would be enough for any sim released in the following decade.
One of the difficulties, would be part throttle power oughtput. But anyway any model based on data gathered from real dynos would be much easier to implement.
"Drown by hand" power cuerves, imitating or copying similar power curves from similar real engines, would be enough for any sim released in the following decade.
One of the difficulties, would be part throttle power oughtput. But anyway any model based on data gathered from real dynos would be much easier to implement.
FGED GREDG RDFGDR GSFDG