Punted Football 5

[GoldDredger]

Yesterday I took a tour of the new Dallas Cowboy stadium and it is an engineering marvel. Above the field is a mammoth 4 sided scoreboard/screen, the bottom of which is 90 feet off the playing field. (Its length extends from 20 yard line to 20 yard line)

There is debate as to whether that is too low and may be hit by punts. I’ve read that the average hang time for an NFL punt is 4.6 seconds. To calculate the height I used the following reasoning, does this seem sound?

Discounting aerodynamics, a punted football will follow a parabolic arc, with exactly half it’s time traveling upwards, and the other half downward. That’s 2.3 seconds going up and 2.3 seconds going down.

Using the formula y= (0.5)(32.2 ft/s sq)(time squared). I calculate the average height based on average hang time is 85.2 feet. A hang time of 4.73 seconds and above translates toa punt 90 feet and higher height.

Does this seem correct?

 

[Spartan5]

http://myespn.go.com/blogs/nflnation/0-10-255/Titans-punter-hits-Jerry-s-video-board.html

Titans punter hits Jerry's video board

August 21, 2009 10:35 PM

Posted by ESPN.com's Matt Mosley

ARLINGTON, Texas -- It's already happened! In the inaugural preseason game at Cowboys Stadium, Titans punter A.J. Trapasso boomed a punt that deflected off the bottom of an enormous video board that stretches from one 20-yard line to the other.

Titans coach Jeff Fisher immediately threw his red challenge flag onto the field as Trapasso pointed to the board. Cowboys coach Wade Phillips had a smirk on his face while players and coaches behind him chuckled.

According to the officials, the play is blown dead as soon as the ball makes contact with the video board and the down is repeated. And that's the exact same thing that will happen in a regular-season game. We've asked Jerry Jones and Wade Phillips about this very thing, but they both thought it wouldn't happen.

I'm not sure if there's a way the video board can be lifted any higher. I'm looking up there right now and it's not like there's much room. I'll ask Jerry Jones about the play after the game. Fisher's the co-chair of the competition committee, but I don't think this is something they've spent much time discussing. My guess is that Fisher instructed Trapasso to kick the ball as high as he could to see what would happen.

Trapasso hit the board three times in pre-game warmups. So far, Cowboys punter Mat McBriar hasn't come close to making contact. I'm sure he's a little embarrassed to be overshadowed by the little-known Trapasso.

AFC South blogger Paul Kuharsky is now trying to find out what would happen if one of Vince Young's passes floated into the video board.

 

[weab]

GoldDredger -There's your answer. Just saw it on TV.

Yeah, it's too low! There's no good excuse for that happening.

 

[Mazenk]

your a beast i first did read this a work heck of board, i calculated 88 ft, toooooo low dang jerry pay me a million ill consult with you and tell you its tooooo low lol!!!!1 nice screeeen!!!!

 

[Mazenk]

4.6 sec!

 

[Mazenk]

all those nerds nit picking at drag...get a life, issac newton said 88 feet if you want to say 86.9 you be correct but im an engineer and i put a factor of safety in everything so go ahead and argue about tenths of a feet nerds!

 

[GoldDredger]

Well well well. Seems that it is all over the news now, check this out.

Dallas Stadium has a design flaw with the screen, funny thing is there is PLENTY of room to raise it. Just 15 more feet and only the most extraordinary punts could hit it.

Sure wish Jerry Jones would put me on the payroll, I'm right here in town and predicted it weeks ago.

Just remember where you heard it first guys.

 

[CPENG78]

GoldDredger,
You most definetely called it and I think that pretty much gives your the right to tell Jerry, "I told you so". Unfortunately I missed the game so I didn't get a chance to watch it live but we all read about it before opeening day. Cool stuff, now if we can somehow send our posts to Jerry because based on the article I read, it doesn't sound like he wants to raise it.

 

[weab]

GoldDredger,

I'm not going to argue over a few tenths. I'll give you props for this one.

Did you hear Jerry Jones actually blame the punter??? Punters only kick that high in order to hit screens.

Looks like that screen is going to stay for now.

 

[lodester]

"concretemasonry" said: Your assumption is a classic mistake made by engineers to make the calculations easier and eliminate the real world. Assumptions may lead you to the calculated result you expect.

It is more accurate is to say this is a classic mistake made by mathematicians, who have the luxury of ignoring anything based in reality should they choose.

As a double-doctorate mathematician once said to me: "The difference between an engineer and a mathematician is that mathematicians make assumptions."

p.s. holy cow this forum software is horrific. Please stop using frames...my eyes, burning.....noooooooo....

 

[concretemasonry]

Engineers should stick to what they know and design the structures. The use and criteria for objects in the area should be in the expected requirements for the use. Any college student can calculate the theoretical track of a an object under the ASSUMED conditions, but real life facts are the most important factors in the real world design of functional fixtures.

I remember years ago when a high hit went into the 4" ventilation hole in between the layers of of the Minnesota Metrodome that was an the air supported dome (now about 30 years old). This was years after the roof successfully sustained a collapse from a snow fall/snow removal and structurally survived. Provisions were made for very unusual high high hits that hit speakers or the guy wires in many indoor and outdoor parks were incorporated into the ground rules that are common and acceptable. The ball went in and was not found until much later. The design criteria should have been based on the criteria and if other items were installed that is the responsibility of the owner/architect/interior designer. Obviously the engineer should not be responsible for the structure built low enough for the undesigned scoreboard assembly and the installed height. It is possible that a 2 1/2 " baseball could go through a 4" hole widely spaced that is 200 feet high. Mesh may have been installed and a few more holes used to make up for the minor air flow, but someone designed and approved the roof structure for all uses and cite some paragraph in the criteria intially if it was described.

The scoreboard in the new Dallas football stadium was was scheduled for a temporary removal for a short term rental for a rock concert (about $1-2 million cost).

It is just an ego situation between a football god and the real world god. Now, punters may be aiming for the known target when necessary and the length is not necessary.
Either the roof height was set out too low in the criteria or the scoreboard was installed too low.

Dick