[SpaceCadet]

Originally Posted by PenelopePitStop

So it's a combination of slowing the car and preventing it from becoming airborne and flipping. So I guess the flaps failed as well?

I would say they sure do fail. You can see them go up once the car goes around, so I'm guessing they must be at least slowing the cars down somewhat. But I'll bet Stewart, Boyer and Busch are thinking the same thing I do - they don't slow down enough to keep them on the ground. Well, I guess it's not fair to say they never work, because who knows how many times they did work. You don't see a lot of flips so those flaps must be doing something right. I think I just talked myself right into changing my mind about them not working. Jeez, I sound like I have multiple personality disorder or something. No, you don't. Yes, I do. No, you don't..........

[PenelopePitStop]

Originally Posted by SpaceCadet

I would say they sure do fail. You can see them go up once the car goes around, so I'm guessing they must be at least slowing the cars down somewhat. But I'll bet Stewart, Boyer and Busch are thinking the same thing I do - they don't slow down enough to keep them on the ground. Well, I guess it's not fair to say they never work, because who knows how many times they did work. You don't see a lot of flips so those flaps must be doing something right. I think I just talked myself right into changing my mind about them not working. Jeez, I sound like I have multiple personality disorder or something. No, you don't. Yes, I do. No, you don't..........

LOL! NASCAR will do that to you!

[Souporscotty]

I think they're designed to slow the car down and let it go airborne "safely" so us spectators get a good show. There are few things better than a good wreck where nobody gets hurt.

[wingkey1]

Originally Posted by PenelopePitStop

So it's a combination of slowing the car and preventing it from becoming airborne and flipping. So I guess the flaps failed as well?

So I guess the flaps failed as well? - Nope. Actually they worked as intended. Car never really "flew", which is what the flaps work towards preventing. Shrub got upside down due to getting sideways and "lifted" by the contact that sent him to the wall, and then got to flipping when his car essentially "tripped" on/over the grass. Increasingly the truly high speed tracks have replaced the grass with pavement in key areas for just this reason. The incident can be seen (over and over should one wish) by searching on "Kyle Busch flip". Car never really got to much of a sideways and flat attitude. Was pretty much set up on two wheels and sideways by the impact prior to hitting the wall.

Simple Simon's post with article is good one. Key in it are that vehicle going sideways at high speed presents itself to the air much in the shape of the wing of an aircraft. Arched top, flat bottom. Arched top creates longer path for the air than path across bottom. This creates low pressure area over the top when compared to the bottom. The higher pressure on the bottom trys to get to the low pressure area of/on the top. Just a fact of science/physics. In simple terms, lift has been manufactured. It's why airplanes fly, and unfortunately it is why cars will try to do same. The flaps disrupt the otherwise smooth flow over the top of the surface. Lift is killed. You can see similar flaps on the top surface of airline planes. They are manually deployed by the pilot when the plane touches down. Why? - Once the plane is "down" they would like very much for it to stay there. Being a private pilot, there have been many a time I wished for those devices on some of my own landings.

[LSC9901]

Originally Posted by wingkey1

So I guess the flaps failed as well? - Nope. Actually they worked as intended. Car never really "flew", which is what the flaps work towards preventing. Shrub got upside down due to getting sideways and "lifted" by the contact that sent him to the wall, and then got to flipping when his car essentially "tripped" on/over the grass. Increasingly the truly high speed tracks have replaced the grass with pavement in key areas for just this reason. The incident can be seen (over and over should one wish) by searching on "Kyle Busch flip". Car never really got to much of a sideways and flat attitude. Was pretty much set up on two wheels and sideways by the impact prior to hitting the wall.

Simple Simon's post with article is good one. Key in it are that vehicle going sideways at high speed presents itself to the air much in the shape of the wing of an aircraft. Arched top, flat bottom. Arched top creates longer path for the air than path across bottom. This creates low pressure area over the top when compared to the bottom. The higher pressure on the bottom trys to get to the low pressure area of/on the top. Just a fact of science/physics. In simple terms, lift has been manufactured. It's why airplanes fly, and unfortunately it is why cars will try to do same. The flaps disrupt the otherwise smooth flow over the top of the surface. Lift is killed. You can see similar flaps on the top surface of airline planes. They are manually deployed by the pilot when the plane touches down. Why? - Once the plane is "down" they would like very much for it to stay there. Being a private pilot, there have been many a time I wished for those devices on some of my own landings.

For anyone that caught the interview you would note that Kyle did say that the entire area should be paved so that the cars wouldn't catch the grass and flip. Yes the flaps did work.

[jks812]

Originally Posted by LSC9901

For anyone that caught the interview you would note that Kyle did say that the entire area should be paved so that the cars wouldn't catch the grass and flip. Yes the flaps did work.

I agree with Kyle too. Think he would've been okay if it hadn't hit the grass. When it happened even the announcers they should pave all the grass areas and stop that.

[oncea3fan]

how often do they replace thier HANS devices, could it be after repeated wrecks that it has been weakened and finally cracked. like a piece of metal you bend it once, it will give ,but keep repeating that motion and will aventurally break/crack.

[jks812]

Originally Posted by oncea3fan

how often do they replace thier HANS devices, could it be after repeated wrecks that it has been weakened and finally cracked. like a piece of metal you bend it once, it will give ,but keep repeating that motion and will aventurally break/crack.

Thats a very good point. I haven't seen anything on how often they use the same ones. Boy if Kyle is using the same one every race, it has been getting a work out lately.

[HMS24]

Thought those roof flaps primary purpose is to keep the car from becoming airborne after spinning. Which Kyle's flaps did, until his tires hit the dirt causing the spectacular barrel rolls. Kinda hard to develop anything that will keep the car rubber side down when it hits dirt going sideways, except maybe paving the infield.

[wingkey1]

Originally Posted by HMS24

Thought those roof flaps primary purpose is to keep the car from becoming airborne after spinning. Which Kyle's flaps did, until his tires hit the dirt causing the spectacular barrel rolls. Kinda hard to develop anything that will keep the car rubber side down when it hits dirt going sideways, except maybe paving the infield.

Actually the flaps never got a chance to come in to play. He was knocked up on to two wheels pretty much upon impact by Stewart. When he hit the wall shortly thereafter, that finished the roll over. He was sliding along upside down just fine till his roof hit the grass.

YouTube - Kyle Busch flips at 2007 Talladega Busch race

[Racer Duck]

Originally Posted by oncea3fan

how often do they replace thier HANS devices, could it be after repeated wrecks that it has been weakened and finally cracked. like a piece of metal you bend it once, it will give ,but keep repeating that motion and will aventurally break/crack.

Rule of thumb that most racers use for helmet and other devices is: once involved in a wreck where the device recieved any stress or impact, replace it. Hans devices are cheaper than necks and helmets are cheaper than heads... I'd guess each driver has several.. Remember, at this level their driving suits cost more than the Hans device and they change driving suits a lot!

[Lefturn]

It was a violent wreck, I bet the crack occured when he hit the wall at the start of the crash.

A good demonstration of roof flaps working would be the wreck at the end of the Sunday race. Joe Nemecheck was backwards and the car was in 'ground effect' as it wanted to fly, but the roof flaps were keeping it low to the ground. The car was floating.... could have been ugly.

YouTube - Kyle Busch , Joe Nemecheck , and Jeff Burton Wreck

[Souporscotty]

Originally Posted by Racer Duck

helmets are cheaper than heads

Even Kyle's?

[Racer Duck]

Originally Posted by Souporscotty

Even Kyle's?

maybe not to you, but to his mommy it is.