- 10,276
- Sacramento CA
- cnd01
@Holdenhsvgtsr You're right that the initial cause for lift was air under the car. That's a no-brainer. My point is that there's no negative force from the fin pushing the car back down. If that was made confusing by me, then my fault. I am asserting that the fin assists the car into the air which was just proven by your post. Recall my argument:
Assume the contact from the idiot Ferrari driver is like the car bouncing through the grass. Lift is given by the rear of the car leaving the ground. The fin pushing air under the wing assists in lifting the right half of the Toyota off the ground. You can see in video of McNish's crash that the car is getting plenty of lift, but it's not enough to overcome its weight. No doubts that the fin is creating some of that.
By acting as a sail, I meant catching and re-directing air. You know best that a rigid sail is a crappy sail, but it's better than no sail.
Obviously, the weight of the car is mass*gravity. With his numbers, that's 3626Nm like what he got.
Drag checks in as 1/2(p)(v^2)(C)(A). Also correct.
A knowledge of fluid mechanics knows that anytime a fluid(in this case air) makes a turn, the pressure increases an amount that can be calculated. When the air hits the fin and turns under the wing, it undergoes an increase in pressure which isn't being factored in. Not to mention, the space it's traveling in becomes confined more as Air is still flying over the fin as the car travels. Is that enough to flip the car by itself? I highly doubt it unless he's going really really really fast.
So essentially, we're both right. I re-ran all of his calculations with unit conversions because those are crucial. His physics are correct. His lift calculation is correct.
You guys want to talk about safety: Why don't these factory teams with all the best engineers figure out a way to create a system that allows air to easily escape that's trapped under the car (and that doesn't mean the lackluster vents near the wheels. Hell, NASCAR does better than that) Channeling the air through and out of the top of the car when it is sideways or backwards is the way to go. Now, I do realize that at high speed, it's next to impossible to stop a flip like that with the huge amount of air put under the car very rapidly. The impulse is pretty high, but that's a project that can actually do some good for safety.
Assume the contact from the idiot Ferrari driver is like the car bouncing through the grass. Lift is given by the rear of the car leaving the ground. The fin pushing air under the wing assists in lifting the right half of the Toyota off the ground. You can see in video of McNish's crash that the car is getting plenty of lift, but it's not enough to overcome its weight. No doubts that the fin is creating some of that.
By acting as a sail, I meant catching and re-directing air. You know best that a rigid sail is a crappy sail, but it's better than no sail.
Obviously, the weight of the car is mass*gravity. With his numbers, that's 3626Nm like what he got.
Drag checks in as 1/2(p)(v^2)(C)(A). Also correct.
A knowledge of fluid mechanics knows that anytime a fluid(in this case air) makes a turn, the pressure increases an amount that can be calculated. When the air hits the fin and turns under the wing, it undergoes an increase in pressure which isn't being factored in. Not to mention, the space it's traveling in becomes confined more as Air is still flying over the fin as the car travels. Is that enough to flip the car by itself? I highly doubt it unless he's going really really really fast.
So essentially, we're both right. I re-ran all of his calculations with unit conversions because those are crucial. His physics are correct. His lift calculation is correct.
You guys want to talk about safety: Why don't these factory teams with all the best engineers figure out a way to create a system that allows air to easily escape that's trapped under the car (and that doesn't mean the lackluster vents near the wheels. Hell, NASCAR does better than that) Channeling the air through and out of the top of the car when it is sideways or backwards is the way to go. Now, I do realize that at high speed, it's next to impossible to stop a flip like that with the huge amount of air put under the car very rapidly. The impulse is pretty high, but that's a project that can actually do some good for safety.
