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Post by the light works on Mar 9, 2014 15:14:10 GMT
This was a common thread on the old boards, and pretty readily debunked using simple logic and mechanical knowledge - but it is still a potentially testable concept.
to summarize: a chain e-mail suggests that a girl was driving on a rain wet road with cruise control on. when she hit a puddle and began to hydroplane, the cruise control became confused, accelerating the car violently out of control. depending on the particular email, it goes so far as to say the car took off like an airplane.
the challenge in testing this is that they will need a wet surface style skidpad, and a variety of cars with cruise controls of various types. the other challenge is safety - because logic indicates that the cruise control WILL make the skid worse, even if it doesn't accelerate the car out of control. theoretically, the skidpad will allow safe runout for a driver, but would it be better to remote control the car?
any thoughts on what sorts of cars should be used? I would be inclined to think at least a front engine front drive, a front engine rear drive, and a rear engine rear drive car - each fitted with wide low pressure tires to make them hydroplane more easily.
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Post by silverdragon on Mar 13, 2014 7:56:08 GMT
Thoughts on the car... and questions of my own. One with "Tampered with" cruise control. I have it in good authority that Cruise control on anything with Traction control WILL, absolutely will, no question about it, "Notice" if you start to aquaplane, as the wheels will loose traction, and cancel the cruise control. It will also beep like a thing that beeps when its set to super-beep to let the driver know as well on more modern vehicles?...
Thoughts on the driver, one that can resist the automatic impulse to "Do something"..... You can have as many conversations as you want, but any driver that gets slightly squirrely and ignores it, shouldnt be on the road. Any accident caused by the incompetence of the driver is 100% down to incompetence and noting at all to do with aquaplaning?... is that a valid topic here or a separate topic for discussion?...
The myth had various guises one of which was that the cruise control would self resume and accelerate .... Not happening I am told. If you hit the brakes at any time, thats it, CC is cancelled there and then until you the driver tell it to "Resume"
How much is modern cars of the assurances I am given I do not know... I didnt drive CC until late 80's early 90's, as we just didnt have enough roads in the UK you could actually use it on?...
Take off.... Again, not happening..? An object in motion and all that, says that unless you actually get a launch action, you aint going up until you push upwards?... an object travelling left to right will continue to go right until it has an upward force, and all aerodynamics on cars have a downwards force dont they?... So unless the car has flipped....
Or are we talking post aquaplane and into the cartwheeling free ride on a roller-coaster you get after you hit the kerb?...
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Post by the light works on Mar 20, 2014 6:17:49 GMT
I drove with cruise control first in the 80s as well. and they have become more sophisticated over the years - but I haven't driven with both cruise control and traction control unless you count the limited slip diff on my service truck - and while I frequently run with cruise control in the rain - I haven't done it when traction is an issue. I did have one car that the cruise control was slightly wonky - it would ratchet up the setting at random intervals. just a couple miles per hour, though.
as for taking off - there are occasionally cars built that can generate aerodynamic lift... but you have to be going a heck of a lot faster than most cars can go before it becomes a factor.
so yeah - I think this is totally bogus - all logic says the cruise control will not accelerate above the set point, and if the drive wheel is spinning, the cruise control will reduce throttle to bring it back to the setpoint. but that does not mean it can be a testable myth.
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Post by maxman on Mar 20, 2014 9:27:12 GMT
As for older cars with cruise control, it would be nice if they could use the earliest versions, but as the first cars to use the original version (a solonoid opening the throttle, using driveshaft rotations to gauge speed) were the 1958 Imperial Crown and Chrysler Newport and New Yorker, there's no chance of Mythbusters getting their hands on them.
However, there is a kit for the Ford Falcon that is a cable, connected to a knob and the accelerator, that simply holds down the accelerator, with a second cable connected to the brake to release the ratchet on the knob when it was necessary to brake. I had a photo of it, but I can't find it anymore.
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Post by silverdragon on Apr 2, 2014 9:00:23 GMT
Max, both systems, as crude as they were, self cancelled when the brake was pressed...?...
This then proves the "Myth" bogus, on the grounds that anyone who didnt hit the brakes when the car gets out of control deserves everything they get...?... Plus the myth stated that the car took over and nothing the driver could do would stop the CC causing an accident.....
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Post by the light works on Apr 2, 2014 14:20:04 GMT
Max, both systems, as crude as they were, self cancelled when the brake was pressed...?... This then proves the "Myth" bogus, on the grounds that anyone who didnt hit the brakes when the car gets out of control deserves everything they get...?... Plus the myth stated that the car took over and nothing the driver could do would stop the CC causing an accident..... none of the variants I have seen posted indicated that the driver had the presence of mind to react.
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Post by silverdragon on Apr 3, 2014 10:07:46 GMT
none of the variants I have seen posted indicated that the driver had the presence of mind to react. And there I call the story Bogus. Bogus because it relies on the premise that we all are daft enough to believe that the driver would not react.... And to be honest, I dont actually want to know any driver who would not react in some way at some point, nor do I want to share road space with them. As soon as a car starts to get squirrelly, does not EVERY driver try to regain control?... I suppose this story would be better if we bust that myth first. Take 100 drivers with a driving licence where you have at least some who have experience of wet weather driving, and a good mix of abilities, from relatively new driver to experienced in all vehicles, and ask them to drive down a half mile run-way, in a skid pan adapted car, one that can remove steering and create a skid. Ask they engage cruise control. At some point, replicate the Aquaplane instance. Count the number of drivers who do not react and try to correct that before its in full unrecoverable skid.... My guess is that count will be approximately somewhere less than zero?... For this myth top continue, you need at least ONE failure. So first on this myth, we have to bust the premise that we had a "Perfect storm" of an idiot driving in torrential rain with Cruise Control on that has absolutely no spacial awareness, will drive full thrutch into a flooded road, and is completely clueless about recovering a vehicle that starts to get out of control.... In other words, first find a driver that should not really have a driving licence. I give you my great aunt Sally..... when she was alive, she is the one who drove into the wrong drive and parked up thinking she was home. It wasnt until she tried to open the front door of the house, that was Blue, that she realise... Her own door was red.
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Post by the light works on Apr 3, 2014 14:48:51 GMT
none of the variants I have seen posted indicated that the driver had the presence of mind to react. And there I call the story Bogus. Bogus because it relies on the premise that we all are daft enough to believe that the driver would not react.... And to be honest, I dont actually want to know any driver who would not react in some way at some point, nor do I want to share road space with them. As soon as a car starts to get squirrelly, does not EVERY driver try to regain control?... I suppose this story would be better if we bust that myth first. Take 100 drivers with a driving licence where you have at least some who have experience of wet weather driving, and a good mix of abilities, from relatively new driver to experienced in all vehicles, and ask them to drive down a half mile run-way, in a skid pan adapted car, one that can remove steering and create a skid. Ask they engage cruise control. At some point, replicate the Aquaplane instance. Count the number of drivers who do not react and try to correct that before its in full unrecoverable skid.... My guess is that count will be approximately somewhere less than zero?... For this myth top continue, you need at least ONE failure. So first on this myth, we have to bust the premise that we had a "Perfect storm" of an idiot driving in torrential rain with Cruise Control on that has absolutely no spacial awareness, will drive full thrutch into a flooded road, and is completely clueless about recovering a vehicle that starts to get out of control.... In other words, first find a driver that should not really have a driving licence. I give you my great aunt Sally..... when she was alive, she is the one who drove into the wrong drive and parked up thinking she was home. It wasnt until she tried to open the front door of the house, that was Blue, that she realise... Her own door was red. we have housing developments like your Aunt Sally's. as for the driver you specify. remember, Mythbusters IS filmed in America. we have no shortage of drivers who will panic and freeze up if something unexpected happens - as well as drivers who ignore deteriorating weather conditions and drivers who think nothing bad will ever happen to them. but I believe the kernel of truth behind all this was a driver who had their speed set too high, conditions deteriorated, they came around a corner, hit a puddle, and were over the berm or into the guardrail before they could set down their phone and take stock.
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Post by silverdragon on Apr 4, 2014 5:50:52 GMT
So this is nothing about the Car, its about an idiotic never should have got licence stupid person who should never drive......
But they still try to blame the car.
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Post by the light works on Apr 4, 2014 15:17:39 GMT
So this is nothing about the Car, its about an idiotic never should have got licence stupid person who should never drive...... But they still try to blame the car. well, yes, it is about a person who is probably underqualified to drive. - but it deals with people not comprehending how cruise control works and proliferating a misconception.
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Post by silverdragon on Apr 5, 2014 12:32:37 GMT
I cant see how this myth can be tested, if it relies on someone driving who is, to be honest, incompetent at driving....
However.............
I am getting an idea, and this is why I like this place, we can go play with things until something appears.
Someone tell Grant to dust of the radio control. I am suggesting R/C of a vehicle, as to be honest, the desired result of the myth is total loss of control and perhaps a crashed vehicle..... I have been "playing" with my own radio control over the last day or two, day one was fitting a waterproof shield under the vehicle which may have just invalidated the results as it will have changed the aerodynamics. But it proved proof of concept. For shield, read I took the body off and wrapped the car in a plastic bag with just the wheels poking out, then popped the body back over the top, held on with Duck Tape.
The idea.... go ahead with normal radio control of a vehicle, full size, but this time, fit a forward camera and have the screen in front of whoever is driving.... if they have had any experience in Forza, GTA, Need for Speed, etc, they should then be able to drive the vehicle "in real time" quite accurate.
Either have a two lane track with central divide that prevents water, and set the remote control on the back of that pick up truck chase car, (same as used in the Myth-BUS jump episode) or a remote station to control the vehicle from.
On the track the target vehicle will run on, introduce water, or even full skid-pan soap solution, to break traction....
Send remote control vehicle down that section, with CC "Engaged" at say 50 mph, so at some point, your R/C will have to engage the cruise control on the vehicle.... I am not aware of a per-set CC that will work from standstill?... I am aware of "Resume" buttons, but I believe they will only work over a certain speed.?... I dont drive Cruise control cars or automatics, so fill in the gaps there as required.
Pass over the skid are with nothing more than light steering input and see what happens.
I would also suggest that the track has a gentle bend in it at some point where this can be repeated on a bend to see if that alters the result.
I am suspecting anything with a half decent Cruise Control will self cancel the CC and glide to a halt. Hopefully.
I suggest a vehicle that does not have modern CC and traction control etc be used as a second vehicle to bust "Period vehicle" complaints.
I also suggest continued tinkering and removal of safety devices to "Encourage" the Cruise control to fight to continue speed, as the vehicle upon hitting standing water would naturally slow down anyway.
My results?... From the one eight scale car I have on a "set" throttle control which I set using trim control on the remote, the vehicle skipped slightly, but continued, nothing I could not easily control with light steering corrections.
I altered that to a deeper puddle. The vehicle bogged down and just ploughed through. Slower, but it continued on course. On a deeper puddle still, it just stopped dead.... then began to float. I dont think I have either the right tyres or the right vehicle for this. Or the right driver, as I accept I was prepared for the puddle and may have been in the right mindset to recover control.
I have now removed the plastic bag coverings from the vehicle and dried it out, and I wont be wanting to play in the water with it again....
Of course, if anyone else has a good idea?....
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Post by the light works on Apr 5, 2014 12:50:57 GMT
I think that on a proper skid pad, they will have plenty of room to test this "live" I am guessing that your RC car simply could not go fast enough to hydroplane on its stock tire configuration.
I can say for certain that a car hydroplaning under cruise control will not abruptly accelerate and take off like an airplane, because I have had occasion to hydroplane a car under WOT, and cruise control will not hold WOT under any circumstances.
and you are correct - modern cruise controls have a lower threshold at around 25 MPH before they will set speed or resume.
the results I expect are that cruise control will not make it hydroplane any easier, and once in a skid, will attempt to keep the drive wheels at the set speed.
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Post by silverdragon on Apr 5, 2014 13:05:35 GMT
Not a whelks chance in a supernova.
Reason being, you and I are ineligible to do the test, as both of us are too sensitive to NOT react when in the car?.... so are most drivers we know.
Thats the reason for remote control, you get no real time feed-back "Through the seat of your pants", no slight twitches on the force-feedback of power assisted steering, no feedback at all from the actual physical steering, and if the cruise control is "set" and all you are left with is steering, you cant stomp the brake....
Next time you are out with a passenger who drives, watch their feet, they intuitively look for the brake when the feel they should slow down?... and that is just a passenger... As a Driver, many many times when you suddenly need to brake, your foot is already there before you have even thought it through?.... So how can you then drive with a lifetimes experience of reactions, and NOT react. That is why I ask for remote control, you cant put an intelligent driver behind the wheel and expect them not to react and try to save the skid.
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Post by the light works on Apr 5, 2014 13:50:35 GMT
Not a whelks chance in a supernova. Reason being, you and I are ineligible to do the test, as both of us are too sensitive to NOT react when in the car?.... so are most drivers we know. Thats the reason for remote control, you get no real time feed-back "Through the seat of your pants", no slight twitches on the force-feedback of power assisted steering, no feedback at all from the actual physical steering, and if the cruise control is "set" and all you are left with is steering, you cant stomp the brake.... Next time you are out with a passenger who drives, watch their feet, they intuitively look for the brake when the feel they should slow down?... and that is just a passenger... As a Driver, many many times when you suddenly need to brake, your foot is already there before you have even thought it through?.... So how can you then drive with a lifetimes experience of reactions, and NOT react. That is why I ask for remote control, you cant put an intelligent driver behind the wheel and expect them not to react and try to save the skid. so hie a stunt driver. they are trained to suppress their common sense.
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Post by silverdragon on Apr 5, 2014 14:45:46 GMT
Still leaves it open to "You didnt do it right" when nothing untoward happens. This is about the "Dumb blonde" who didnt do anything... if the car under test doesnt skid out of control, then to some, OBVIOUSLY its because you had a trained driver at the controls?...
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Post by the light works on Apr 5, 2014 17:53:52 GMT
Still leaves it open to "You didnt do it right" when nothing untoward happens. This is about the "Dumb blonde" who didnt do anything... if the car under test doesnt skid out of control, then to some, OBVIOUSLY its because you had a trained driver at the controls?... I sincerely expect a car that a stunt driver deliberately puts into a hydroplane will skid out of control - if he leaves the cruise control in charge. cruise controls are not programmed to recognize and compensate for a skid. (note that this would not be a car with active traction/stability control, which might be good enough to control its own skid) what I don't expect it to do is accelerate, whether controllablly or not.
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Post by silverdragon on Apr 6, 2014 6:11:05 GMT
I can agree that a trained stunt driver may be able to do nothing, but, when he does, and still nothing happens, I expect other people to complain that maybe he did do something to control the car?...
Will early CC cars self cancel. I think they did. I also think that the cruise control works by noting the speed of the driven wheels. Therefore, if the rear wheels break traction, they will not exceed the set cruise speed, which kind of negates that "Accelerates out of control" claim?...
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Post by the light works on Apr 6, 2014 15:42:34 GMT
I can agree that a trained stunt driver may be able to do nothing, but, when he does, and still nothing happens, I expect other people to complain that maybe he did do something to control the car?... Will early CC cars self cancel. I think they did. I also think that the cruise control works by noting the speed of the driven wheels. Therefore, if the rear wheels break traction, they will not exceed the set cruise speed, which kind of negates that "Accelerates out of control" claim?... right, exactly. cruise control turns the drivetrain at the set speed. where it calculates the speed from varies - sometimes engine speed, and sometimes driveline speed, but never (as far as I know) from actual ground speed; simply because that would be unnecessarily difficult to monitor. which means, yes, the "accelerates out of control" claim is negated, and that is what I am looking to bust. my expectation is the car begins to skid, and continues to skid, but doesn't launch out of control.
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Post by silverdragon on Apr 7, 2014 8:57:42 GMT
So in fact, all of us reading this, are expecting a "Busted" result..... But as always, we are happy to be wrong.
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Post by the light works on Apr 7, 2014 13:57:26 GMT
So in fact, all of us reading this, are expecting a "Busted" result..... But as always, we are happy to be wrong. especially if it involves cool footage.
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