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Doughnuts?
- Thread starter jlhog
- Start date
Ty
Elio Addict
At some of the motocross races I used to participate in back in the 80's, they used to take a break and have a race of three wheelers. This was before quads were around. Anyway, those races were more about who managed to not flip over rather than who was fastest. You definitely didn't want to be on the brakes in a curve. The same goes for all those Robins and other three wheel cars. It isn't that you need to drive differently, it is the fact that in certain emergency situations, your options of avoidance become extremely limited. Thus, two wheels up front to prevent flipping.
Maurtis
Elio Addict
Exactly, as we saw in the flip video of the Slingshot. It flipped when the rear swung around you now have the "wrong" three wheel configuration with one wheel in front. They claim that was because traction control was off, but still something to keep in mind. I remember reading articles in high school about how the original Viper could do highway speeds in reverse. Definitely not something to try in the Elio.
WilliamH
Elio Addict
Watched it a number of times.
The front right came off the ground while the rear was swing left.
With the driver on the left side all the weight and momentum was going left.
That's the problem with rear wheel drive in a tadpole when the driver is off center.
Sethodine
Elio Addict
So what your saying, is that the tandem seating arrangement of the Elio is yet another stabilising factor in its design?
WilliamH
Elio Addict
I'm saying that in the particular case in question the off center weight loading could very well have been a contributing factor since all factors showed a loading shift to the left. That means that in a static situation the CG would be to the left of the center line of the Slingshot.
Is tandem seating in an Elio a stabilizing factor? It certainly isn't a negative factor.
But here is the clip of the Slingshot going over so you can be the judge.
--->
skygazer6033
Elio Addict
Yes. A single center seat or tandem is inherently more stable. The big issue of stability in any 3 wheel configuration is keeping the CG as near to the center of the planform as possible. With a driver only in a side by side your CG is already bias to that side. The CG slops around just like water in a pan is affected by acceleration forces. When it slops outside the triangle formed by the contact patches of the tires on a trike the trike rolls over.
Sethodine
Elio Addict
Then there is also the problem with power push-over in a traditional trike arrangement (1 Front wheel steering, Two rear wheels powered, high center-of-gravity rider) When turning at speed, the rear drive wheels pushing behind the center of gravity causes the rider to lean forward and out, further throwing off the CoG and causing the forward flip.
By putting two wheels up front, you help to contain the CoG within the "triangle" and improve traction while steering. By putting the drive wheels up front, it changes to a pulling configuration, which pulls the vehicle's weight through the curve rather than pushing it around. And by lowering the rider's position (into the "driving" position like a car, instead of riding atop/astradle the vehicle) you make it harder for the rider's mass to act as a lever against the weight of the vehicle.
The slingshot, being side-by-side, doesn't really fix the CoG problem because the driver is still outside of the contact-point triangle, and the drive wheel in back means it is still pushing the vehicle instead of pulling it around the corner. For these reasons, the Elio's configuration is the most stable of the trike designs. The only way to improve on it would be to tilt the cabin like the Carver. While the Carver is very stable, it would be even better if it was a Tadpole layout.
By putting two wheels up front, you help to contain the CoG within the "triangle" and improve traction while steering. By putting the drive wheels up front, it changes to a pulling configuration, which pulls the vehicle's weight through the curve rather than pushing it around. And by lowering the rider's position (into the "driving" position like a car, instead of riding atop/astradle the vehicle) you make it harder for the rider's mass to act as a lever against the weight of the vehicle.
The slingshot, being side-by-side, doesn't really fix the CoG problem because the driver is still outside of the contact-point triangle, and the drive wheel in back means it is still pushing the vehicle instead of pulling it around the corner. For these reasons, the Elio's configuration is the most stable of the trike designs. The only way to improve on it would be to tilt the cabin like the Carver. While the Carver is very stable, it would be even better if it was a Tadpole layout.
I was going to say something about power-to-the rear in that video, but it was not as big a factor as two other things.
First, the driver didn't recognize the problem soon enough. A quick counter-steer is the normal recovery for that. But definitely he exceeded the limit.
Yes this was a three wheel skills issue. A four wheeler could have rolled as well, but at a higher threshold, and maybe a time-slice later. And counter steering is not as imperative in the case of a four wheeler. In a four he could have tried a drifting power turn at the last moment. In this case of a 3 wheeler, a power turn would have given him a spin-out, not the effect he would want.
In a power turn some amount of quick inside steering plus petal-power is required. In the three wheeler, it requires not as much steering and much-much more power. But again, this most likely would end up as a spinout, followed by some other tragic result. The spin out is required to phase past the point where the car is broadside to his momentum. But once past that there is no elegant recovery back to the race.
This has nothing to do with the loud and trashy peel outs you see three wheelers with rear drive do on you tube. These guys are not in a high speed turn when doing that.
Now back to the rear power, he should also have backed off the power prior to the turn. What happened at the last moment, with the tilt, the rear tire became set at an angle, losing tire patch, and traction. This added a bit of slide to the rear just at the time the driver was trying to do his (late attempt at) counter steering. If not for that, maybe his counter steering might have recovered before roll over. It placed him broadside to his momentum.
Another issue he had, there was extra force in the roll since he was bouncing back from the prior turn. And so this is the second issue, just as stated before, he seem to judge what the car would do from the prior turn, but his human weight was to the one side, and he didn't take that into account.
Center seating might have helped his perception, but is that better? Side seating means lower roll over on one side than the other. Center just means they are balanced. Either one could be better depending on a match up to driver skills. I would expect center seating is easier to learn than sociable. And the feel on a left turn can help you better predict the right. Is that better? Just depends.
Overall, I'd say he was still too used to 4 wheel racing.
Having said all that above, it only applies to rear power tadpoles.
For racing front wheel drive, three and four wheel cars are indeed very much alike. Neither have any power turn capability. Most of what you do racing a four wheeler (FWD) applies to a three as well. There is one exception, in the three wheeler you can counter steer (and ease back off power) to put the inside wheel back on the ground. At that point you might be off the track.
Overall predicting the effect of your speed in a turn is indeed more important in a three wheeler. Granted SUV's are still more tricky.
First, the driver didn't recognize the problem soon enough. A quick counter-steer is the normal recovery for that. But definitely he exceeded the limit.
Yes this was a three wheel skills issue. A four wheeler could have rolled as well, but at a higher threshold, and maybe a time-slice later. And counter steering is not as imperative in the case of a four wheeler. In a four he could have tried a drifting power turn at the last moment. In this case of a 3 wheeler, a power turn would have given him a spin-out, not the effect he would want.
In a power turn some amount of quick inside steering plus petal-power is required. In the three wheeler, it requires not as much steering and much-much more power. But again, this most likely would end up as a spinout, followed by some other tragic result. The spin out is required to phase past the point where the car is broadside to his momentum. But once past that there is no elegant recovery back to the race.
This has nothing to do with the loud and trashy peel outs you see three wheelers with rear drive do on you tube. These guys are not in a high speed turn when doing that.
Now back to the rear power, he should also have backed off the power prior to the turn. What happened at the last moment, with the tilt, the rear tire became set at an angle, losing tire patch, and traction. This added a bit of slide to the rear just at the time the driver was trying to do his (late attempt at) counter steering. If not for that, maybe his counter steering might have recovered before roll over. It placed him broadside to his momentum.
Another issue he had, there was extra force in the roll since he was bouncing back from the prior turn. And so this is the second issue, just as stated before, he seem to judge what the car would do from the prior turn, but his human weight was to the one side, and he didn't take that into account.
Center seating might have helped his perception, but is that better? Side seating means lower roll over on one side than the other. Center just means they are balanced. Either one could be better depending on a match up to driver skills. I would expect center seating is easier to learn than sociable. And the feel on a left turn can help you better predict the right. Is that better? Just depends.
Overall, I'd say he was still too used to 4 wheel racing.
Having said all that above, it only applies to rear power tadpoles.
For racing front wheel drive, three and four wheel cars are indeed very much alike. Neither have any power turn capability. Most of what you do racing a four wheeler (FWD) applies to a three as well. There is one exception, in the three wheeler you can counter steer (and ease back off power) to put the inside wheel back on the ground. At that point you might be off the track.
Overall predicting the effect of your speed in a turn is indeed more important in a three wheeler. Granted SUV's are still more tricky.
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slinches
Elio Addict
The shorter wheelbase and the CG being further aft due to the rear drive probably contributed too.