Understanding why cars develop aero lift or downforce is the first step in developing modifications to change that! Buy my book at www.amazon.com/dp/B0C87VYVL8 or Amazon in your country.
When I was learning to fly I bought loads of books to get me through the exams. Having done a degree in Physics I had a tome on fluid dynamics, but thought tensor calculus probably unnecessary for the ground exams. Eventually I found the perfect book: _Model Aircraft Aerodynamics_ , Martin Simons, Nexus Special Interests Yes - a book for modellers was better than the official flight training books. I must get a copy of your book - I have one of your other titles and like it a lot. 17:12 Just the kind of car to pose with down King's Road, Chelsea.
In physics classes back then they also mentioned air speed to identify whether we have a load or a lift, but I think that it makes more sense to talk about pressures, since the air speed will be a consequence of it, just like wind in the atmosphere. I think that talking about pressures make it more intuitive to understand that negative pressure or vacuum will suck any thing to fill that gap causing load or lift. And we can easily visualize a ball bouncing on a car to understand what will happen to air particles and then deduce where high and low pressures will be.
Sort of. Not just a ball bouncing off a surface, but a stream of particles also bouncing off each other. At subsonic speeds, air starts being influenced by an object far in advance of its arrival and distorts around that object as necessary. The key is to not disturb those particles too much, especially not by dragging them forward with you.
Interesting, I am loving these videos. I currently have a MK3 Audi TT with the active spoiler that extends and retracts and I've been very interested in the flow of air during when its extended and when its not. I do believe thats why they added the fixed spoiler to the MK1 TT due to the crashes people were having at high speed autobahn runs back in the late 90s.
Another great video! I would like to know more about the side fins some wings have, have they got a purpose? For example Koenigsegg jesko absolut has two big fins on the back? How are those involved in downforce, stability, drag etc of the car?
The most straightforward but least practical way to get more flow velocity under the car is to reduce the cross section area, IE lower the car. Another way to get more flow velocity under the car is, instead of lowering the car, using flow structures (vortices) to reduce flow under the car which in turn reduces CSA. This is much harder to do because the turbulence from the tire interferes with these flow structures, which means you have to manage that wake(by pushing it outboard) which generates extra drag.
@@JulianEdgar I love the knowledge you're sharing and I'd love to add downforce to my car...The thing is, even if I were to buy this measuring equipment, I'd have to start making my own Aero mods... I'm an IT guy, I don't craft wings for a living. How to fix that problem ? I can't just go around buying every aftermarket spoiler until I find the best one either .....
I've watched all your videos and shared them about as well. Great stuff and well explained... @ 12 00 It's not much of a splitter, but how much down force did it actually generate and at what speed?
Yes, the splitter's measured downforce is covered in the book. www.amazon.com.au/Vehicle-Aerodynamics-Modification-Development-alternative/dp/B0C87VYVL8
Julian, I have the insight and was interested in your thoughts on spats covering the front wheels similar to the rear? I noticed the extended front piece before the tire openings. Similar effect? Wish you were still on the Insight forum.
17:12 Is the _patch_ the static port used with reference to the classy pitot-on-a-pole at the front, or is the tube on the patch a pitot so that the difference is with reference to ambient pressure?
When you mention that amateur sedan race cars should make undertrays you need to understand that most low level racing classes forbid undertrays and splitters can't go beyond the front axle line. That's how they end up with cars equipped with wings, splitters and nothing else that we, looking from the outside, would consider a must in terms of aero parts. Shit i've even seen fancy rear diffusers on cars that had no underbody panels at all.
I would have thought that that's a bit mad really. given how much time you end up going into gravel. maybe its so when they crash there isn't a solid piece of ply bending into another car.
