This is a thread over in the 'hackin' section of advrider, however their system refuses to allow me to register, so I'll ask over here.
Please understand that I've never driven a sidecar rig, but am trying to learn as much as I possibly can. For an experienced rider, this is all now instinctive.
Reading Hal Kendall, and reading the thread many times, it appears that there are four modes that occur on a 'sidecar-hander' turn.
Mode 1 - all's hunky-dory, three wheels firmly planted
Mode 2 - sidecar wheel lifts because of centrifugal force, but if you were to draw a line between the centre of gravity (at rest) and the rear wheel, that line would still be at less than 90* (zero* being a line between the tug wheel and the sidecar wheel)
Mode 3 - sidecar wheel still lifted, but the line in Mode 2 is now at 90*, and the county fair trick of riding with one wheel suspended is achieved.
Mode 4 - line now >90*, roll over begins.
It would seem that Mode 2 would still be a stable operating position, so long as the rate of change of the angle of the line was a zero value. If the rate of change exceeds zero by any substantial degree, mode 4 (bl**dy disaster) will quickly occur.
It would seem that rolling off the throttle when you feel the sidecar wheel feeling light, or braking with the rear wheel of the tug alone would 'catch' a rollover, unless the momentum of the lifting moment was great enough, at which time the only solution would be to turn away from the car. This would be similar to a sideways stumble, when you move your foot laterally to re-establish your balance.
Is this all fundementally correct? If not, please advise.
Thanks and best,
Michael
This is not a confusing situation when you have ALL the information.
The center of gravity is not the only force to be computed here.
There is also the center off effort meaning the effort of the centrifugal force in a turning situation.
The center of effort moves as the machine begins to lift. It move upward to apply even greater lift to the machine
until it overcomes the center of gravity and the machine goes over.
As the sidecar rises, the center of gravity also moves towards the outside of the curve.
When the center of gravity is far enough to the outside direction, there is no saving it.
The result is a roll over crash.
The only way to avoid the roll over crash is to turn away from the center of effort, (towards the outside of the turn).
Unfortunately this moves you into the lane of oncoming traffic or off the outside of the road.
If you wish to learn the feel of these forces, I suggest you not do it on the road.
Go to a large EMPTY parking lot to practice any maneuvers.
Have a friend along who can lift the machine off of you and give medical aid should you happen to over do your experiments.
I was hoping for some more input here.
What I was considering making was an audible aid for a novice (me) for when the lateral forces entered the 'amber' zone, and removing speed could still correct things.
'One time shot' user defined parameters would be the physical design of the rig, ride parameter would be the ballast, system inputs would be a three-axis accelerometer and a three-axis inclinometer.
No substitute for experience, of course, but a tool to teach (myself) so I don't kill myself until I get the experience. Also the device would lack the ability to look ahead at the road, it could only report on current conditions.
Making things like this are easy and cheap these days, less than $50 in 'bits'.
You would be far better off using the time to just practice and learn the feel for the warning signs. It becomes instinctive after a while.
No matter what kind of warning device you build, it will not be as good as learning to feel it. Just go to a deserted place and practice.
Ah! a true engineer! Road Camber is also a highly influential parameter that would be difficult to remotely sense.
A simple audible signal would be the screams coming from the car, tho I doubt it would come soon enough for the driver to recover the rig. Another idea would be a “Sphincter Pressure Sensor" connected to a buzzer.
Sidecarist credo:
"Better to go into a curve slow and come out fast then to go in fast and come out dead."
On a slightly more serious note, you could mount a micro-switch on your hack wheel swingarm such that as its suspension gets close to full extension (i.e. weight on the sidecar wheel approaches zero) that it turns on a dash light and/or sounds an alarm. Same setup would work on the bike’s rear suspension for hot lefties. This would give you perhaps a half second extra reaction time.
The ultimate sensor is your own perception, calibrated by much trial and a little bit of error. Even the "Sphincter Pressure Sensor" requires the driver to anticipate the rig's reaction to up-coming road conditions.
The best sensor is common sense.
The others will be working fine after you are upside down, or in the oncoming lane facing a semi.
Lonnie
I always get asked by bikers. no so much by the general public;
How hard is it to drive a side car, as some where they have heard of all the fun !!
I make it simple to understand.....
Any motorcycle, side car or not.... HAS NO CENTER OF GRAVITY in motion, the pivot point is where the tire meets the pavement.
This is why you Lean Steer a 2 wheel bike. You CAN"T LEAN a side car rig, so in a RIGHT HAND turn, its trying to pivot on the bottom of the tires meeting the pavement....
(Pointing to the steer & pusher.) EVERYTHING ABOVE THIS POINT is trying to go to the outside of the turn, and Voila the chair is "Flying" !!!
On a Left Hand turn, This pivot point is the steer tire and the side car tire, again, where the bottom of the tire meets the pavement,
and the easiest way to explain the experience of this is to say, your car just completely lost its right front tire, where do you think you are going?!!
Hopefully in the rasberries... and NOT making you be a GOOD BIKER.... to save your rig.... by letting it land on YOU!!
Before any gadget or device sending out a signal would work you're already in over you're head and the accident is happening. I submit that with good instructions and some seat time anyone with common sense can learn how to drive a motorcycle with a sidecar attached. We started teaching individuals how to drive with a sidecar over forty years ago and all of the more than four hundred and fifty students must have learned something because not one had a wrecked driving a sidecar rig because of driver error. We did have eight accidents that we documented and each time they were people that were brothers, cousins, best friends, or just ignorant individuals with no sidecar training that "knew it all" and took the sidecar rigs out and wrecked them. Some people need more help than others when it comes to learning new things but with practice anyone can become good at driving with a sidecar.
Back in the 1990's a new trend appeared with a new type airplane called "an Ultralight". Every guy that ever wanted to fly was attracted to this new sport. My group with all of us being old experienced pilots would do some of the different Air Shows. Shows like The Sun' in Fun at Lakeland Florida that was always held in the Spring and then we would head up to the EAA AirVenture at Oshkosh Wi. the first week in August. At Sun'in Fun they had an area set up for the Ultralight's and sure enough every year from three to four would kill themselves flying some contraption that they had built or it would be pilot error. The FAA wouldn't even bother to go over and investigate because it wasn't in their jurisdiction when it came to flying. The point I'm trying to make is that to many times in life people don't get the proper instructions or they don't spend the time learning the in's and outs of something before it's to late and they end up upside down. There is nothing like seat time in any kind of vehicle to get proficient at driving it.
The original topic was about going into a turn to hot so I figured that I would post a picture of a simple thing that I don't think you could call a device but more of a diagram that we placed on the speedometers of over three hundred of our customers rigs.
We found that our sidecars had a tenancy of lifting up in a right hand turn above 38 MPH without any ballast or without a sidecar passenger. I'm not talking about slow sweeping turns but abrupt right hand turns. So early on I had just the solution to make driving my sidecars easier. I had been around airplanes from my earliest memories and some airplanes use a color coded marking system on some of the instruments. So I adapted what I had learned years earlier around airplanes and placed it on my own personal speedometer. It's very simple; keep it in the green when going into a sharp right hand turn and the sidecar wont lift up. As your driving along and approaching a right hand turn a quick glance at the speedometer is all that's needed. If your in the "Red" slow down until your in the Green" and if a little braking is needed, use it to get you into the green. Even today forty plus years later I still use the color code system on my own sidecar rig. But like anything in life some in this next generation that I've been helping along will "blow off" the color code system. The trick worked back in the day and it works today.
(Warning): Your sidecar may lift up at a different speed without ballast or a passenger than my rigs. If you us this simple trick do some test runs to determine your green and red line perimeters. One other element that must be considered when determining the green and red perimeters and that would be the radius of the right hand turn.
In any turn there are a couple of things you should do.
The first is to shift your weight into the direction of the turn. Move your tush off the saddle if you have to. In RH turns (with the sidecar mounted on the right side of the motorcycle) get some of your weight transferred toward the sidecar. In LH turns (with the sidecar mounted on the right side of the motorcycle) shift your weight away from the motorcyle on the LH side. Hang out in the wind if you need to do so.
The second is done simultaneously with weight shifting and that is to "feather" or "load" your front brake a bit which causes the back tires to slip on the pavement just enough to prevent a wheel coming up across one of the tipover lines.
An integral part of turning is preparing for a turn and you should practice, practice, practice it until you come proficient at it. Remember to slow down a bit before the turn as well.
Ballast does help a bit though . . . I just put a 3/16" steel plate in 3/4 of the Texas Ranger body today. 🙂
Johnny Sweet - 9/4/2013 7:19 PM
Before any gadget or device sending out a signal would work you're already in over you're head....
By the time of the signal, it'd be too late to initiate the techniques described by cmaridersa:
cmaridersa - 9/4/2013 9:34 PM
In any turn there are a couple of things you should do.... The first is to shift your weight into the direction of the turn.... The second is ... to "feather" or "load" your front brake a bit.... and you should practice, practice, practice it until you come proficient at it....
With practice you will learn your rig's tendencies and be prepared well ahead of the lift.
Also, the ONLY situation in which I have been able to purposely, briefly lift the sidecar to tighten a curve is in very slow greater than 90 degree right hand corners -- corners, not curves, think 2nd gear stuff.
Lee
MB5+TW200+CRF250L+GTV300+INT650
XL883R w/Texas Ranger Sidecar
Zuma 50F + Burgman w/Texas Sidecar<Mrs. SwampFox
Best sensor is still the "butt sensor", but it needs some time and play around for to find the limits. At Racewayservices on afternoon 1.July I got blamed by Hellen the accountant, that she didn't like how I played with the rig on the parking lot. The Ural Patrol is sturdy and like a heavy stone compared to my Jawa and MZ Rig, but these 15 minutes told me that at getting to the edge the Ural behaves pretty simmular to those ultra light rigs. Result: on the following 12.000km in the 2 month we were travelling over all kind of roads and tracks we had only one close call that blew 3 spokes in Anchorage. But Thomas my son and me had a lot of fun on the safe side.
Specially the Canadian customs officers face at the top of the world highway was funny to observe: "You have an idea how late it is?, 3 minutes to 9PM"
Well something like that I had thought that it would occure when the gas station attendant in Chickken said "You have 1 1/2 hours for these 45miles..."
The last Alaskan citizen we saw were lots of gold panners and Caribu herds who delayed us.
So its in your 4 letter sensor.
Yuhuuu.
PS: The moose is already a canadian fellow
On this short race 1/3 of the back tire thread got eaten up in a finger snip.
That evening we learned too for what are forest fires good for: Sun set photos (some even at noon)
PPS: A few days earlier we asked: "When it will become dark?" - " Hmmm, in a month or so!"
