Tire burning fools

[AriLea]

This thread is titled just a little like a WWF call to a fight.
The point here is, people have a lot of confusion about the dynamics of cars, and especially three wheel cars.
The image you see is snapped off of a video on the 3wheelers face book page. This guy is showing how easy it is
to burn a donut into the pavement with this Morgan style delta-trike. (rear wheel drive, engine up front)

For the most part people like this guy think it's cool (presumably). But all I see is a failure of the vehicle to give
adequate and safe traction. If it is that easy to 'burn out', it's potentially deadly in odd weather conditions, and elsewhere.(gravel roads anyone?)
And everything gets worse with more power. Other things get worse with weight moved to the rear using this delta layout and RWD.

The fix? Weight over the traction. (only fixes the one issue)
The best fix? Two wheels forward, weight low and forward (55-70%), plus traction forward too.

Example of a technically specific term for this platform is 2F1R-FWD-F65%CGLTT (CG=CenterOfGravity,LTT=LowerThanTopOf-24in-Tires). A delta-trike or tadpole trike, even autocycle, just doesn't seem to hit the mark for me. BTW, LCT or Lower-Than-Center-Of-Tires would be a rare find in a daily driver.(have to include the driver/1-passenger weight in that measurement) And that description assumes the vehicle takes advantage of the width of the road, or somewhere over 5.5ft(1700mm). I prefer a 6ft minimum (1800mm) for US roads (track-width=>TW6ft). And a wheelbase length over 120% of the width, and not more than 240%. (wheelbase=>WB9ft). And full cabin, tandem seating.
2F1R-FWD-F65%CGLTT-TW6ft-WB9ft-FCTS, yes, an easier term would be nice. (The Bex Formula?, the Arak Assertion? lol)

But like the WWF, I get lots (lots) of push back from enthusiasts of other formats. But they sometimes value tire-burning fun
over and above safe, predictable dynamics. Other contentious values exist as well, but that one was one of them.

Everyone decides how much safety they want. But do they know how much they have?

 

[AriLea]

I just wanted to add something. When you look at research into over-steer and understeer occurrence in a delta trike, opposite from a tadpole layout, it actually swaps up to three times. Over-steer is useful in racing when you want to power turn, but on the street people are not always ready to manage that. It is particularly problematic in a delta-trike because a swap can happen without warning. And you have up to three points for that. But it can be mitigated by a lower center of gravity and a longer wheelbase as the DeltaWing has done. This softens the swap, and pushes the points of occurrence to more diverse points of speed, more apart. With a fine trained driver, DeltaWing can put that to use. But on the street, for us normal people, not so much. If your CG is low enough and wheelbase is long enough, you will slide long before one or more of the three swapping points happens. The old trike ATV's, with a high CG and small footprint, had this happen very close together at very low speeds in turns.

The 2f1R-FWD platform above has only one point, moving into understeering. And it's very soft, simply increasing as the speed of turn increases. So I'm sorry racers, no power turns.

However, there is one dynamic that changes that. Since the rear suspension in a common tadpole does not change it's geometry in a turn, it is possible with a soft front suspension to lean so much that the rear tire patch reduces to a very small area. This can cause a sudden over-steering effect, because as that lean happens you can get a loss of grip to the road, and then a sudden slide. And that can result in a follow-up stage as a sudden change of either over-steer or understeering depending on how much and when the slide occurs. The craft can suddenly lean back, and resulting in a sudden grabbing of the rear, giving back and forth rolling momentum. Yes it can get weird. Oh yes, I remember now, we call that chaotic. It's much worse when the power is at the rear of a 2F1R-RWD.

So we keep the CG low, and the suspension stiff and including some anti-sway. That mitigates the issue.