The Delta Wing - What is This Crazy Looking Thing?
We were invited to chat personally with Ben Bowlby about the Delta Wing project this week.
Mark Cipolloni and Scott Morris chatted with Ben and were increasingly sold on the concept.
There is too much this concept to cover in one brief article, so we are going to cover it for you in a 7 part series that will break it all down for you.
Let us begin by saying we were not about to really question the design itself from an engineering standpoint, as one cannot argue with hard data. But on instinct and experience, we could not help but have many questions about the design that seem to completely defy conventional logic or practice. We too are engineers, though not racing car designers, so we jumped at the opportunity to talk tech with Ben.
In speaking with him personally, one can tell that Ben is deeply passionate about this concept, and really does not want to be given the credit for it, as it would not have happened if not for the efforts of a team of people.
Now, many articles have been written about this concept thus far, and we thought we would take a more step-by-step kind of walk-through, as this is how our view began to change on this car as well. Though we cannot really say we are totally convinced, it is certainly not because it isn’t a very well thought-out design.
Our first question was that it just simply looks like the car will not turn. Ben said everything thus far is telling them that it turns amazingly well, and actually changes direction much more quickly than the current car.
But when you look at it, if you have driven racing cars or even been a keen observer for any length of time, your brain tells you that this thing just isn’t going to turn.
That is what really intrigued us.
Ben had a very clear way of explaining it.
Generally we have always “forced” a car to turn, by applying a couple of physical principles. The first is a polar moment of inertia component that causes you to want locate most of your weight toward the middle of the car. This is true in general, but even beyond inertia considerations, because this reduces the weight against which the wheel must generate resisting forces (friction) to get the car to turn.
So to simplify the Delta Wing approach, they made the front very light with significant mechanical grip, and the rear relatively heavy, thereby moving the point of rotation way back from the more traditional rotational center. This puts very little weight on the front, and reduces the amount of force needed to get it to change direction.
So, it’s almost like a Big Wheel, that all of us old-guys had when we were kids. Those things had a very low center of gravity so they would not tip over, and your butt was more or less sitting over the rear axle of the thing; Yet, when you went to turn the wheel, it turned on a dime. Mine of course, had a rubber front wheel on it, so it turned even better. We found that you could simply wrap a certain sized bike tire right around the plastic big wheel front. We left the hard plastic wheels on the back though, so I had quite the loose handling Big Wheel.
Another interesting component comes from the parasitic nature of the inside wheel during a turn. With the outside wheel doing most of the work, the inside wheel basically becomes a burden. We have all seen this happen when a driver begins to turn while still carry a bit of brake into a turn and that inside wheel locks up in a puff of smoke. Well, what if you just get rid of that wheel completely? By locating the turning wheel toward the centerline of the vehicle, you eliminate that problem.
Along the notion of stability, maintaining a consistent (flat) geometric plane requires three point, not four. Take two pieces of paper. Cut one into a triangle of any shape. Take the other and make it a rectangle. Pin the corners down on a piece of cardboard. Now with each piece flat on the table, try to raise any one corner. The triangle maintains its flat surface, where the rectangle becomes curved. Simply speaking, which is more simple and consistent?
So these things combined, basically answer how and why this car can turn. Of course, we will know more when it gets on track, but that is what all the simulations are telling them right now. Computer simulations have reached a level and form now, where it is hard to question, and most always confirmed in the real world.
This concept is also where the errant reports of rear-steering started to come from.
So completes part one. The car turns. This is what you need a real race car to do.
The amazing part is that it does it without down-force from wings, and that is another point we will cover in coming installments in this series. Stay tuned.
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