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gbrandwood
09-21-2008, 02:48 PM
http://www.youtube.com/watch?v=Hea_kKD17a8




C3RS
09-21-2008, 03:13 PM
I understood nothing ... but I think it's done for. :D
therefore, I will not continue to talk ... :p [:D]

PeteInLongBeach
09-21-2008, 05:46 PM
Let's see your advanced approach on a taller one. Many of the kerbs around here are from the 1920s, and can be about a foot tall. For those, I usually do the 1-step dismount.

gbrandwood
09-21-2008, 06:02 PM
I also filmed the one-footed version today on the same 3.5 inch curb. Just need to do the editing (takes longer than the filming!).

I'll repeat the filming (sans adv. kerb mount) at another location as soon as I can.
5-6" curb should be fine. 1 foot is bigger than I have ever done. I'd probably PA that.
On an x machine, no problem. On my "classic" e, no way! Feel free to send in your Video.

gbrandwood
09-22-2008, 06:23 AM
Original video deleted - replaced with this:

http://uk.youtube.com/watch?v=gxua7E0VTug

gbrandwood
10-06-2008, 06:36 PM
Let's see your advanced approach on a taller one. Many of the kerbs around here are from the 1920s, and can be about a foot tall. For those, I usually do the 1-step dismount.

http://www.youtube.com/watch?v=vK0yImFGSTg

Here's a quickie of a 6 inch kerb. Can't find a bigger kerb when you need one!

Gihgehls
10-06-2008, 06:48 PM
So, the Advanced approach is to use slow motion? I can't find that setting on my PT...

gbrandwood
10-07-2008, 03:04 AM
Nope. There is no slow motion mode on your PT. Don't waste any time looking for it :rolleyes:. The manoeuvre should be performed slowly though. Slow-mo was used in the video so the user can see the tyres never lose contact with the kerb.

Bob.Kerns
10-07-2008, 10:25 AM
Nope. There is no slow motion mode on your PT. Don't waste any time looking for it :rolleyes:. The manoeuvre should be performed slowly though. Slow-mo was used in the video so the user can see the tyres never lose contact with the kerb.

On my i2, I find that if I do it slowly, I bang the bottom back of my battery case. Maybe because I'm heavy enough that with all the weight concentrated on the corner of the curb, it indents the tires enough to eliminate the bit of clearance?

I was quite startled the first time it happened!

I can avoid that by having a bit of forward motion so my tires (and battery) clear the curb.

Gihgehls
10-07-2008, 12:33 PM
Nope. There is no slow motion mode on your PT. Don't waste any time looking for it :rolleyes:. The manoeuvre should be performed slowly though. Slow-mo was used in the video so the user can see the tyres never lose contact with the kerb.

So if I fly over the curb with great speed, is that the "super advanced" approach? :)

MagiMike
10-07-2008, 12:40 PM
So if I fly over the curb with great speed, is that the "super advanced" approach? :)

I was wondering if I was the only person who on approaching a 3 1/2 inch curb at 12.5 MPH just kept on going. No need fer a special advanced approach.:eek:

Bob.Kerns
10-07-2008, 12:48 PM
I was wondering if I was the only person who on approaching a 3 1/2 inch curb at 12.5 MPH just kept on going. No need fer a special advanced approach.:eek:

Yeah, but...

I presume you mean DOWN, not UP!

I like gliding. I don't mind flying.

It's that bump at the end of the flight I don't like.

Where possible, I find a curb cut, even if I have to slow down to do it.

I suppose if I had an inevitable drop on a routine route, I'd probably fly over it too. If you're going to let the wheels disconnect from the curb, you lose any help from the Segway on slowing your descent anyway, so why slow down?

It's going to be just as jarring at 2.5 MPH as it is at 12.5 MPH!

The worst thing, by far, is to go over a curb SLOWLY, with the crown of the road trapping you at the bottom -- sort of trapped between a curb and the edge of the road. The curb cut at the cross walk in front of our elementary school is like that -- not actually a curb, but steep enough on both sides, if you go slow, it will growl at you trying to get it out of the depression. In either direction.

KSagal
10-07-2008, 01:11 PM
So, the Advanced approach is to use slow motion? I can't find that setting on my PT...


My slo-mo switch is right next to my hover switch... Don't tell me you forgot to get that option???:rolleyes:

KSagal
10-07-2008, 01:15 PM
...The worst thing, by far, is to go over a curb SLOWLY, with the crown of the road trapping you at the bottom -- sort of trapped between a curb and the edge of the road. The curb cut at the cross walk in front of our elementary school is like that -- not actually a curb, but steep enough on both sides, if you go slow, it will growl at you trying to get it out of the depression. In either direction.


I do not do a 'regular commute' but I do have a spot or two that I have to deal with this type of a depression...

I find that on my i2, I can navigate this better one wheel at a time, so instead of approaching this depression at a 90 degree angle, I do it between 45 and 60 degrees...

The base does a side to side sashay, kind of like a slolom on skis...

Bob.Kerns
10-07-2008, 01:50 PM
I do not do a 'regular commute' but I do have a spot or two that I have to deal with this type of a depression...

I find that on my i2, I can navigate this better one wheel at a time, so instead of approaching this depression at a 90 degree angle, I do it between 45 and 60 degrees...

The base does a side to side sashay, kind of like a slolom on skis...

Yes, good point, I do that in a number of locations. It's still better done faster than dead slow.

In this location, I often have school children on either side.

I also find it helps to sort of push down with my feet and jump up as I enter the depression. This gives a small burst of speed to the base, and some bounce from the tires, and a reduction of my apparent weight as it comes up the other side.

I don't think that strategy works if you take it at much of an angle.

It doesn't take a LOT of speed; pedestrian walking speed is plenty.

KSagal
10-07-2008, 01:59 PM
Yes, good point, I do that in a number of locations. It's still better done faster than dead slow.

In this location, I often have school children on either side.

I also find it helps to sort of push down with my feet and jump up as I enter the depression. This gives a small burst of speed to the base, and some bounce from the tires, and a reduction of my apparent weight as it comes up the other side.

I don't think that strategy works if you take it at much of an angle.

It doesn't take a LOT of speed; pedestrian walking speed is plenty.

Didn't I read that you stand something like 6 foot 19 inches on that seg, and weight in at like 600 pounds with gear? You would think that the schoolkids scatter when you come barrelling thru their intersection!:D:D

I know I would, especially if you were hopping up and down on the platform at the time! :eek:

Just kidding... I know you only stand 6 foot 15 or so...;)

Bob.Kerns
10-07-2008, 02:13 PM
Didn't I read that you stand something like 6 foot 19 inches on that seg, and weight in at like 600 pounds with gear? You would think that the schoolkids scatter when you come barrelling thru their intersection!:D:D

I know I would, especially if you were hopping up and down on the platform at the time! :eek:

Just kidding... I know you only stand 6 foot 15 or so...;)

I think it's closer to 6 foot 16, with helmet.

I'm looking to add some nice fake feather or such that will survive tree branches and doorways.

With Seg, gear, and all, we probably come in around 350 pounds.

But the kids run TOWARD me, above a certain age. Toddlers through preschool sometimes have their doubts.

I was standing at a school function on Saturday, talking to someone, when suddenly I get hugged around both legs! Too low for it to be my daughter, I look down, and it was a second grader (my boss's daughter, actually).

I've had zero negative reactions from school officials, the after-school programs, children, nor parents. Nor the local police supervising the bike-to-school event.

Responsible operation is a factor, no doubt. And a lot of people got to see me in store isles, or standing and talking, etc. -- more than just zipping along at 12.5. I slow when encountering pedestrians on the trail or sidewalk, especially so if there are kids or dogs.

I like to think I've done a fair bit to raise people's comfort factor around here.

But I still startle people if I've been following along behind for a while waiting to pass, or if they see me coming on the freeway overpass and think they have to get off.

gbrandwood
10-07-2008, 03:53 PM
I was wondering if I was the only person who on approaching a 3 1/2 inch curb at 12.5 MPH just kept on going. No need fer a special advanced approach.:eek:I don't take all of this too seriously guys - it's a bit of fun. But I think it is safer to slow down when leaving a kerb rather than sail straight off the edge. I can't think of a situation where not slowing down would be safer than slowing down. Super advanced approach? Sure - post some videos of it. I love the old SegwayNM video.

gbrandwood
10-07-2008, 04:17 PM
On my i2, I find that if I do it slowly, I bang the bottom back of my battery case.I had that happen once on my old i167. Never since with many more kerbs under my belt. I think perhaps, from memory, it might have been the corner of a kerb, meaning the place the wheels left the kerb was actually behind the outermost edge of the kerb, making it easier to catch the back. I might have also leaned backwards slightly as a newbie.

I suppose if I had an inevitable drop on a routine route, I'd probably fly over it too. If you're going to let the wheels disconnect from the curb, you lose any help from the Segway on slowing your descent anyway, so why slow down?

It's going to be just as jarring at 2.5 MPH as it is at 12.5 MPH!

Who's suggesting the wheels disconnect from the kerb? The point of doing it slowly is that the wheels do not leave the kerb.

The worst thing, by far, is to go over a curb SLOWLY, with the crown of the road trapping you at the bottom -- sort of trapped between a curb and the edge of the road. The curb cut at the cross walk in front of our elementary school is like that -- not actually a curb, but steep enough on both sides, if you go slow, it will growl at you trying to get it out of the depression. In either direction.I think I know exactly the kind of situation you refer to here and I've already added some details about this in v1.5 of my guide. But I've never encountered such a steep slope over the edge of a kerb where what you describe would be a problem. I'm not saying they don't exist - obviously they do as you and others are talking about them. Bottom line, we each glide in a manner that suits us. Hopefully, we take risks that we believe are measured and acceptable. If, in such a situation, you think it is best to glide off at speed, then good luck to you. I wish you success. For me, as such circumstances are not common, I would probably (in the absence of a drop-kerb), use "my" Beginner approach. But, I would quickly find a route that avoided that particular necessity in future.

Bob.Kerns
10-07-2008, 06:09 PM
I had that happen once on my old i167. Never since with many more kerbs under my belt. I think perhaps, from memory, it might have been the corner of a kerb, meaning the place the wheels left the kerb was actually behind the outermost edge of the kerb, making it easier to catch the back. I might have also leaned backwards slightly as a newbie.

Who's suggesting the wheels disconnect from the kerb? The point of doing it slowly is that the wheels do not leave the kerb.

I think I know exactly the kind of situation you refer to here and I've already added some details about this in v1.5 of my guide. But I've never encountered such a steep slope over the edge of a kerb where what you describe would be a problem. I'm not saying they don't exist - obviously they do as you and others are talking about them. Bottom line, we each glide in a manner that suits us. Hopefully, we take risks that we believe are measured and acceptable. If, in such a situation, you think it is best to glide off at speed, then good luck to you. I wish you success. For me, as such circumstances are not common, I would probably (in the absence of a drop-kerb), use "my" Beginner approach. But, I would quickly find a route that avoided that particular necessity in future.

I'm comparing going over just barely fast enough to clear the curb so the battery doesn't get banged, vs full tilt.

I've never done it full tilt, actually -- since I've always only gone off a curb after considering whether it was really necessary. But I don't see as it would increase the difficulty. Just the consequences, if something WERE to go wrong -- which is probably the best argument for more restraint. But except for banging the battery, and the unpleasant jarring, I so far haven't had the slightest issue with going off a curb. No instability on landing. It seems as safe as the landing surface, so going over at speed might actually be safer if the near surface is poor. (Say, an ice patch, or uneven pothole, or broken storm drain grate).

Still, I'd rather find another route than depend on speed to clear obstacles!

Where possible, I do avoid problematic spots. The one by the elementary school, I need to use when accompanying my daughter.

Gihgehls
10-07-2008, 07:37 PM
The trick is to not be accelerating or decellerating by the time you get to the curb. You have to make sure that the platform is level when you fly off of it. Doing it as shown in the video leaves the opportunity to accidentally go backwards, leading to tragedy.

Bob.Kerns
10-07-2008, 07:57 PM
The trick is to not be accelerating or decellerating by the time you get to the curb. You have to make sure that the platform is level when you fly off of it. Doing it as shown in the video leaves the opportunity to accidentally go backwards, leading to tragedy.

Accelerating shouldn't pose a problem, right? Nor, for that matter, should a deacceleration, so long as it's small compared to the speed? And if you did reverse and hit the curb, you'd be going rather slowly, and the possibility would exist to simply step off, and avert the tragedy?

That last isn't intended to deny it's a risky situation -- just a way out. I suppose an intentional simultaneous drop-and-dismount could be done, and avoid the unpleasant drop while being quick. But I think I'd still have the battery-strike issue, so I don't think I'll be trying it.

I hit an up curb once (misalignment at a curb cut), and it didn't go, and stepped off. Going slowly; I was able to step BACK, and of course it then popped right up over the curb, and I wrestled it to a standstill. I regretted getting off, though -- it startled a nearby pedestrian-rights activist and flushed him out of hiding, and I got another spurious lecture about what I was doing being supposedly illegal and how dangerous these things were.

(This was in San Francisco, of course).

No such thing, of course, it just occupied the space I was about to enter, and I continued to occupy the space I had desired to leave -- both of which were empty.

But it would have been more smoothly handled to just back up a few inches and retry, without the dismount.

In fact, that might make a good video -- up against some small obstruction, get stick shake, lean back and forward again, and roll on over.

KSagal
10-08-2008, 12:28 AM
I don't understand this comment about curb strikes on the battery...

The battery does not extend beyond the tires in any direction, so if the curb is straight where you go off, as long as both tires leave at the same time, the battery cannot hit.

If you go off the curb one wheel at a time(at an angle), you can hit the battery while the seg is one wheel up and one wheel down.

If you go off a curving curb, or off a corner, you can strike the battery but not otherwise...

On a slightly different note, I have had a hitch on the back of my seg since 2003, and it does extend beyond the line of the tires, but only slightly. Because of this, I always glide down curbs, when I must, at a couple miles per hour. This will give enough distance from the curb when the seg travels vertically down the face to have it not hit my hitch...

Furthermore, gliding down too slow is dangerous in that new gliders especially will have a tendency to lean back a bit in an effort to reduce their speed as they transition from horizontal movement to vertical movement at the edge of the curb... This means that the seg is tending to back up at the moment it hits the bottom, and the jarring of the landing, with the backing up of the segway against the curb face can be hard to deal with...

For all these reasons, I suggest a modest speed of 2 or 3 mph for curb drops... More than that is not needed, but the seg is easier to deal with if moving at a modest pace in this environment, in my opinion...

Still, I endorse the videos I have seen so far, as very reasonable, and a useful tool and starting point for low hour seggers.

Bob.Kerns
10-08-2008, 01:40 AM
I certainly didn't expect battery strikes, for the very reasons you state.

These are straight-off-the-curb exits, straight curbs, with reasonably sharp edges on the curbs. The only way I could see for it to happen is for the curb edges to be indenting the tires under the 260 pounds or so of load (+ Segway).

I do keep my tires fully inflated.

At some point, I'll try some static experiments. In the meantime, I try to have some forward velocity on the rare occasions I do such maneuvers.

gbrandwood
10-08-2008, 07:39 AM
The trick is to not be accelerating or decellerating by the time you get to the curb. You have to make sure that the platform is level when you fly off of it. Doing it as shown in the video leaves the opportunity to accidentally go backwards, leading to tragedy.There is always the opportunity for something to go wrong - and the potential for leaning backwards is pointed out in the guide notes which accompany the videos. This is why the approach is dubbed the advanced approach, as opposed to the approach a beginner should use. And certainly, the advanced approach may be less necessary on smaller kerbs and I wouldn't expect a newbie to try the advanced approach on a tall kerb or indeed sail off the kerb at speed.

Accelerating shouldn't pose a problem, right? I think it would pose a problem. Again, I've had a bash at describing this in my guide but essentially, if your wheels leave the ground (traction) and you are level, i.e. not accelerating or braking, the wheels will turn at the same speed they turned whilst on the ground. Accelerating or braking during "air-time" instructs the PT to spin up the wheels faster or slower. The PT says, hold on, there's no traction here, spins up the wheels to top speed then shuts down. You don't want that to happen - but is only really likely if you catch a lot of air or make significant changes to the platform angle.
But it would have been more smoothly handled to just back up a few inches and retry, without the dismount.

In fact, that might make a good video -- up against some small obstruction, get stick shake, lean back and forward again, and roll on over.I mention this in my guide but no video. I think you're right, it might make a good video and will add it to the list. I need to start repeating the vids on an i2, x2 etc.

gbrandwood
10-08-2008, 07:40 AM
Furthermore, gliding down too slow is dangerous in that new gliders especially will have a tendency to lean back a bit in an effort to reduce their speed as they transition from horizontal movement to vertical movement at the edge of the curb... This means that the seg is tending to back up at the moment it hits the bottom, and the jarring of the landing, with the backing up of the segway against the curb face can be hard to deal with...

For all these reasons, I suggest a modest speed of 2 or 3 mph for curb drops... More than that is not needed, but the seg is easier to deal with if moving at a modest pace in this environment, in my opinion...

Still, I endorse the videos I have seen so far, as very reasonable, and a useful tool and starting point for low hour seggers.Agreed and thanks.

Bob.Kerns
10-08-2008, 09:23 AM
I think it would pose a problem. Again, I've had a bash at describing this in my guide but essentially, if your wheels leave the ground (traction) and you are level, i.e. not accelerating or braking, the wheels will turn at the same speed they turned whilst on the ground. Accelerating or braking during "air-time" instructs the PT to spin up the wheels faster or slower. The PT says, hold on, there's no traction here, spins up the wheels to top speed then shuts down. You don't want that to happen - but is only really likely if you catch a lot of air or make significant changes to the platform angle.

You're only dropping a few cm. A 10 cm curb is only 71 ms. I'm pretty sure it doesn't shut down in this short a time under any circumstance; it would be unsafe. And I doubt it spins the wheels arbitrarily fast, either; it won't add traction. It has tight control over the motor speed.

If you're leaning forward, you'll NEED an extra bit of push when you hit to restore balance.

I'm not arguing you should recommend accelerating, though! I don't even recommend routinely leaping off curbs. It's hard on device and rider both. I'd consider it more of an emergency maneuver. I know there are those that consider it great fun. I'd rather treat my machine gently, and myself as well.

Gihgehls
10-08-2008, 01:30 PM
I don't understand this comment about curb strikes on the battery...

You're only considering curbs without curves if you don't understand. There are curbs you could go down in which the wheels will be clear of the curb before the center of the platform is.

Accelerating shouldn't pose a problem, right? Nor, for that matter, should a deacceleration, so long as it's small compared to the speed?

Like brandwood says, changing the platform angle while there is zero traction leads to an unhappy segway and a riskier landing. If you've never seen how fast the wheels will spin up in this instance you would be amazed if you did. Think of the full force of the 2.5 HP motors spinning up to max speed. I'd estimate they get up past 20 mph before the seg shuts down, and they spin up in probably less than a 3rd of a second. It's a scary amount of power.

gbrandwood
10-08-2008, 02:36 PM
Bob, you can test this. Put your PT on a stool so the wheels are both free to move. Press the mat to engage balance
mode. The wheels won't do much yet. Now, tilt the Segway forward slightly. Watch the wheels rev up and frighten the life out of you. This is what I was describing. Now, if you're not in the air too long, this might not occur but the faster you leave the kerb, the more chance it will get. Plus, they don't need too rev all the way up to cause you a problem.

KSagal
10-08-2008, 02:49 PM
I don't understand this comment about curb strikes on the battery...

The battery does not extend beyond the tires in any direction, so if the curb is straight where you go off, as long as both tires leave at the same time, the battery cannot hit.

If you go off the curb one wheel at a time(at an angle), you can hit the battery while the seg is one wheel up and one wheel down.

If you go off a curving curb, or off a corner, you can strike the battery but not otherwise...

On a slightly different note, I have had a hitch on the back of my seg since 2003, and it does extend beyond the line of the tires, but only slightly. Because of this, I always glide down curbs, when I must, at a couple miles per hour. This will give enough distance from the curb when the seg travels vertically down the face to have it not hit my hitch...

Furthermore, gliding down too slow is dangerous in that new gliders especially will have a tendency to lean back a bit in an effort to reduce their speed as they transition from horizontal movement to vertical movement at the edge of the curb... This means that the seg is tending to back up at the moment it hits the bottom, and the jarring of the landing, with the backing up of the segway against the curb face can be hard to deal with...

For all these reasons, I suggest a modest speed of 2 or 3 mph for curb drops... More than that is not needed, but the seg is easier to deal with if moving at a modest pace in this environment, in my opinion...

Still, I endorse the videos I have seen so far, as very reasonable, and a useful tool and starting point for low hour seggers.

[quote=Gihgehls;181960]You're only considering curbs without curves if you don't understand. There are curbs you could go down in which the wheels will be clear of the curb before the center of the platform is.
...quote]


I don't understand your statement. I stated that I knew that a curve in the curb at the point where you go over it can cause a battery strike. Your comment did not take into affect all that I said...

The comments that I had said I did not understand were those that stated that the curb was straight, yet there was still a battery strike. That is the part I did not understand...

Bob.Kerns
10-08-2008, 02:58 PM
Bob, you can test this. Put your PT on a stool so the wheels are both free to move. Press the mat to engage balance
mode. The wheels won't do much yet. Now, tilt the Segway forward slightly. Watch the wheels rev up and frighten the life out of you. This is what I was describing. Now, if you're not in the air too long, this might not occur but the faster you leave the kerb, the more chance it will get. Plus, they don't need too rev all the way up to cause you a problem.

Yes, I can (and should) test this. A bit trickier, though, is testing how quickly it slows when they get traction.

Also, spinning the wheels should torque toward removing the tilt.

Now, if one off the wheels gets traction on landing before the other -- THAT is scary, no question.

I should be clear I'm not arguing for a position here, but trying to work my way (and our) way toward a more detailed understanding.

If the wheels can spin up in 71 ms, they can also slow down pretty quick, too. But there are a lot of different scenarios to consider.

Five-Flags
10-08-2008, 03:41 PM
Yes, I can (and should) test this. A bit trickier, though, is testing how quickly it slows when they get traction.

Also, spinning the wheels should torque toward removing the tilt.

Now, if one off the wheels gets traction on landing before the other -- THAT is scary, no question.

I should be clear I'm not arguing for a position here, but trying to work my way (and our) way toward a more detailed understanding.

If the wheels can spin up in 71 ms, they can also slow down pretty quick, too. But there are a lot of different scenarios to consider.

It might be interesting to see just what speed they reach in attempting to get the platform level. If you perform the test that Gareth described, and measure the Revolutions per Second or RPS (photocell & a dot of white paint to a counter). Then multiply the highest RPS by the circumference of the tire (tyre) and convert the result to MPH (KPH) you will see how fast the platform will try to jump out from under you when the wheels touch down.

It would be a brief peak value, as the controller will do a shutdown if it continues to have no traction, but I'll bet it is over 20 MPH (simply guessing).

This instantaneous acceleration will be detected in the BSA within 10 ms. However, the controller has to recognize that this is out of limits, reverse the voltage, and apply maximum deceleration to get back under you -- hopefully in the next 10 ms. If not, three-tenths of a second will seem a LOT longer as you, the Seg, and the ground perform a very quick and interactive dance.:):):)

Bob.Kerns
10-08-2008, 04:03 PM
It might be interesting to see just what speed they reach in attempting to get the platform level. If you perform the test that Gareth described, and measure the Revolutions per Second or RPS (photocell & a dot of white paint to a counter). Then multiply the highest RPS by the circumference of the tire (tyre) and convert the result to MPH (KPH) you will see how fast the platform will try to jump out from under you when the wheels touch down.

It would be a brief peak value, as the controller will do a shutdown if it continues to have no traction, but I'll bet it is over 20 MPH (simply guessing).

This instantaneous acceleration will be detected in the BSA within 10 ms. However, the controller has to recognize that this is out of limits, reverse the voltage, and apply maximum deceleration to get back under you -- hopefully in the next 10 ms. If not, three-tenths of a second will seem a LOT longer as you, the Seg, and the ground perform a very quick and interactive dance.:):):)

I'm not sure where this "three-tenths of a second" bit comes in. You'd be airborn for about 70 ms, much less than one-tenth of a second..

Gihgehls
10-08-2008, 06:41 PM
[quote=Gihgehls;181960]You're only considering curbs without curves if you don't understand. There are curbs you could go down in which the wheels will be clear of the curb before the center of the platform is.
...quote]


I don't understand your statement. I stated that I knew that a curve in the curb at the point where you go over it can cause a battery strike. Your comment did not take into affect all that I said...

The comments that I had said I did not understand were those that stated that the curb was straight, yet there was still a battery strike. That is the part I did not understand...

It was a conditional statment. "If you don't understand, than this must be why. etc etc."

thanks for clarifying :)

Gihgehls
10-08-2008, 07:12 PM
I'm not sure where this "three-tenths of a second" bit comes in. You'd be airborn for about 70 ms, much less than one-tenth of a second..

I'm not sure where this "70ms" bit comes in. A 6 inch drop at 9.8 m/s/s is 0.176 seconds or 176ms, almost two-tenths of a second.

Edit: I read back and I see we are talking about two different sized curbs :)

Bob.Kerns
10-08-2008, 11:22 PM
I'm not sure where this "70ms" bit comes in. A 6 inch drop at 9.8 m/s/s is 0.176 seconds or 176ms, almost two-tenths of a second.

Edit: I read back and I see we are talking about two different sized curbs :)

And I've been a bit overworked lately, and did the algebra in my head incorrectly. I divided by two when I should have multiplied. After the square root, I was off by a factor of two. Sleep deprivation does strange things.

I am rather puzzled by why, upon reading your post, I should suddenly realize my error -- that I should even recall it well enough. But there you are, I saw your post and immediately knew what I'd done. Weird...

So thanks for the comment that led to the correction. I absolutely HATE being wrong, so anything that shortens the time I'm wrong is always much appreciated!

Five-Flags
10-09-2008, 09:58 AM
I'm not sure where this "three-tenths of a second" bit comes in. You'd be airborn for about 70 ms, much less than one-tenth of a second..

Sorry, that was supposed to be three hundredths -- three cycles of the BSA scan immediately before and including touchdown.

Bob.Kerns
10-09-2008, 10:46 AM
Sorry, that was supposed to be three hundredths -- three cycles of the BSA scan immediately before and including touchdown.

Right, now I have to go back and reconnect that with MY corrected figure (142 ms, vs the 71 ms I miscalculated), and figure out what the hell we were talking about!

My wife keeps talking about wanting to buy this high-speed video camera (currently only available in Japan, I think). It would be perfect for capturing this sort of thing -- how fast the wheel accelerates. I can do the momentum/energy calculation to find what the effect would be.

Though not, it appears, in my head.

I guess I'd need to take off the wheels to measure the moments of inertia of the wheels and the rest of the unit.

Mr_Laurenzano
10-17-2008, 10:31 PM
And I've been a bit overworked lately, and did the algebra in my head incorrectly. I divided by two when I should have multiplied. After the square root, I was off by a factor of two. Sleep deprivation does strange things.

I am rather puzzled by why, upon reading your post, I should suddenly realize my error -- that I should even recall it well enough. But there you are, I saw your post and immediately knew what I'd done. Weird...

So thanks for the comment that led to the correction. I absolutely HATE being wrong, so anything that shortens the time I'm wrong is always much appreciated!


I hate when this happen too, tired and a little slow, but I do know when I foucs launching off park benches on my segway that .03 of a second was interupted by my feet leaving the platform for .01 of a second and with all that math going on over and over again it brings back a little qoute I hold dear.
By the level and by the square... thats all I remember.
Leave level, land level, heal toe heal toe.

Next week we will determine PSI and up curb hop heights and limits.
Don't forget your brain bucket.

Crash

Bob.Kerns
10-18-2008, 11:04 AM
I hate when this happen too, tired and a little slow, but I do know when I foucs launching off park benches on my segway that .03 of a second was interupted by my feet leaving the platform for .01 of a second and with all that math going on over and over again it brings back a little qoute I hold dear.
By the level and by the square... thats all I remember.
Leave level, land level, heal toe heal toe.

Next week we will determine PSI and up curb hop heights and limits.
Don't forget your brain bucket.

Crash

How did you get up on that bench?

I think "by the level and by the square" has something to do with Freemasonry.

Brain buckets are important, indeed. Traumatic brain injury makes life a struggle.

william collins
10-18-2008, 02:37 PM
Too meet upon the level and part upon the square..Is Masonic and has been one of my signatures..My Lodge is Eclipse #259, Rutherford,NJ
I'd like poll how many here are Masons?:)

Mr_Laurenzano
10-18-2008, 04:22 PM
I was just wondering what would happen.

Masonary benches are better they don't shake like those wooden ones.
tanks Bill.

The head bone is conected to the toe bone. Set off a curb lightly and step off to accend.

Has any one tried base jumping off a segway, shaken not stired.

Crash
Have a nice day ya all.

Bob.Kerns
10-18-2008, 06:40 PM
Has any one tried base jumping off a segway, shaken not stired.


I guess it wouldn't work too well for the Segway to have its own chute, nor to go without. So you'd need to treat this as a tandem jump.

At least until the Segway gains enough confidence to jump solo...

DesertSeg
06-22-2009, 08:13 PM
Too meet upon the level and part upon the square..Is Masonic and has been one of my signatures..My Lodge is Eclipse #259, Rutherford,NJ
I'd like poll how many here are Masons?:)

I'm not but my dad is a 33rd degree and does degree work all over California. I was in the DeMolay in high school but the local Masonic lodge was practically dead by the time I was old enough and I would have been the only member under age 70 had I joined!