Jet engine sim for testing 9/11 planes

Originally posted by Zaphod58
Sure there's jet blast. But it's going to be level with the engine. It's not going to blast things along the ground, and rock cars.

Thanks for admitting at least there is jet blast.

Why wont jet blast rock the cars if the jet is within feet of them?

Do you think if a person is 6 feet away from a plane flying over that jet blast will not hit them?





[edit on 6-4-2008 by ULTIMA1]

reply to post by weemadmental

Go back and read the thread I have already addressed this.

www.abovetopsecret.com...

Is he flying a large, slow moving aircraft with the flaps extended?

Not if it's OVER them. And they weren't within "feet" of the plane. It was travelling over them, at least as high as the top of the lightpole. Unless the exhaust somehow turns after it leaves the engine it's going to go in a straight line. Unless the plane was flying at ground level where the cars were, they wouldn't feel a thing from the exhaust.

I don't know if it's deliberate or not, but you are confusing jet blast and wingtip vortices. Jet blast travels in a STRAIGHT LINE from the engines as several of us have stated repeatedly. Wingtip vortices are what would affect anything on the ground.

[edit on 4/6/2008 by Zaphod58]

Originally posted by ULTIMA1
Thanks for admitting at least there is jet blast.

Everyone has admitted there is jet blast.

Originally posted by ULTIMA1
Why wont jet blast rock the cars if the jet is within feet of them?

Because the cone of the jet blast only extends a few feet above and below the level of the engine. This has been explained repeatedly.

Originally posted by ULTIMA1
Do you think if a person is 6 feet away from a plane flying over that jet blast will not hit them?

Not if the jet is 20 feet or so above them. The Boeing website has jet blast hazard cones under each aircraft type. They don’t even bother to show the cone in flight because it’s a non-factor, they only show it on the ground. You can also find plenty of documents online showing the way that wake turbulence/vortexes drop down and drift.
Here, knock yourself out:
www.boeing.com...
www.faa.gov...

Originally posted by Zaphod58
Not if it's OVER them. And they weren't within "feet" of the plane. It was travelling over them, at least as high as the top of the lightpole.

Well according to one witness it feet from him as it went by and hit the generator trailer.

Originally posted by defcon5
Because the cone of the jet blast only extends a few feet above and below the level of the engine. This has been explained repeatedly.

But i have shown the witnesses have stated their cars were rocked by the blast.

I am still waiting for any evidnece that debates the evidnece i have shown about jet blast.

[edit on 7-4-2008 by ULTIMA1]

And for the 5th time, you are confusing jet blast with wing vortices. Which I'm seriously starting to think you are doing on purpose.

reply to post by Zaphod58


Right, first the people/vehicles weren’t jet blasted (we’ll just skip the vortex/wake turbulence/jet blast issue for the moment since its like slamming my head against a brick wall ), then they were rocked by the blast. The aircraft passed within feet of a witness. How many feet, 10 or 1000 feet? People do have the tendency to remember certain events in an exaggerated fashion, and to use embellished language when retelling a story for dramatic effect. That is one of the problems with that Craig CIT guy, he basis his research too much on eyewitness testimony. Unfortunately, if you ask ten different witnesses of an event about it, you’re going to get ten different stories. Then to make matters worse, many people feel that if their story is not spectacular enough then they will not receive attention about it. Either way though, Ultima cannot seem to make up his mind on what the evidence is. It appears he changes it from post to post, just to carry on the argument.

Strawman argument at its finest…
This thread is starting to remind me of arguing with a teenager.

Unless the jet blast was aimed at the cars, why would it affect them. The cars were no behind 77 in the air, they were on the ground the engines were exhausting gases into the air aimed up at various degrees. The jet blast followed 77 and along the flight path which was a constant descent into the Pentagon. I am sure some dissipating jet blast effects may of hit some cars, but the little bit of wake turbulence would be dropping and making cars move just as much. The impact was a big jolt and would be felt for a mile or two.

[edit on 7-4-2008 by beachnut]

Originally posted by Zaphod58
And for the 5th time, you are confusing jet blast with wing vortices. Which I'm seriously starting to think you are doing on purpose.

Well the FAA has regulations on length between planes taking off becasue of jet blast.

We all know that the major turbulence is caused by low speed landings with gear and flaps down, not high speed and clean. So the one of the casues of turbulence at the Petagon would have been jet blast.

Originally posted by ULTIMA1
Well the FAA has regulations on length between planes taking off becasue of jet blast.

You think that maybe again that could be because you’re dealing with two vehicles at the same level, AKA on the ground. You must be playing with us at this point, I don’t see how else you could not figure this out by now. The jet blast on one aircraft will create lift on, and possibly cause FOD damage to another aircraft which is also on the ground behind it on take off run-up. The reason for the separation between one taking off and one landing is in case the one taking off has to abort take off. The reason for the separation between landing aircraft is due to wake turbulence/wingtip vortexes.

www.metacafe.com... e%20images.eatliver.com

Point proven, the people and the cars in the video arent blown about, there is no evidance about the wind vorticies or jet wash affecting any one or thing and the 747-400 is a much heavier that the 757, and the aircraft is in the landing config with flaps down, no wash!!

Can we now close this thread and stop these people going on and on with no shread of evidance

Wee Mad Mental

Originally posted by ULTIMA1

Originally posted by weemadmental
1. a short time is all they needed, plus aircraft engines are very stable, fighter jets during the gulf wars flew at this height on a regular basis to avoid SAM's / AA fire.

2. the period of time the jet was overhead would have been very short, know from experince that a tornado fighter jet at afterburner at 40-45ft ( at end end of runway road runs past it) will rock a panel side van but not blow it over, and these engines produce more thrust than the boeing ever would.

1. Airliners use turbofans, military fighters use turbojets. Fighters fly high to aviod SAMs and AA, not ground level like the plane at the Pentagon.

2. I guess you have not seen all the videos of airliners blowing cars and people around?

[edit on 5-4-2008 by ULTIMA1]

Actually no, most modern fighter aircraft use low bypass trubo-fans and not turbojets. Only older aircraft like the F-4 Phantom use turbojets like the J79. And while flying high might keep you safe from triple A it will make you a big fat target for any SAM battery.

Ultima is partially correct in what he is saying. I invite you to stand on the beach at St. Maarten whilst something big like a 747 lands, and decides to go-around!

Low enough for ya? www.airliners.net...

How about this: www.airliners.net...

Actually no, most modern fighter aircraft use low bypass trubo-fans and not turbojets. Only older aircraft like the F-4 Phantom use turbojets like the J79. And while flying high might keep you safe from triple A it will make you a big fat target for any SAM battery.

I agree.

[edit on 7-4-2008 by mirageofdeceit]

Wake. Vortices. NOT jet blast. Jet blast travels in a straight line. Wake votices roll off the wingtip and head to the ground. That's one of the point of winglets. When wake vortices roll off the wingtip, you lose lift, winglets make the wing longer, and keep them from rolling off towards the ground as much. But no matter how you look at it, if jet blast was hitting the ground it would be a miracle because it would be bending 90 degrees as it left the exhaust.

Definitely. I've edited my post above to be clearer in the first sentence.

Originally posted by ULTIMA1

Originally posted by Zaphod58
And for the 5th time, you are confusing jet blast with wing vortices. Which I'm seriously starting to think you are doing on purpose.

Well the FAA has regulations on length between planes taking off becasue of jet blast.

We all know that the major turbulence is caused by low speed landings with gear and flaps down, not high speed and clean. So the one of the casues of turbulence at the Petagon would have been jet blast.

ULTIMA....perhaps the good guys, defcon and Zaph haven't gotten thru to you yet, so I'll chime in...

Up above you stated take-off separation was due to jet blast? Completely wrong. The timing between take-offs is entirely due to....spacing for ATC purposes. AND, a 'heavy'....that is, any airplane capable of take-off weights over 250,000 lbs, is designated a 'heavy'...irrespective of its actual weight. A B757-200, although not designated a 'heavy' in ATC parlance, or in ATC communications, is still treated with the same separation standards since it has be come to the attention of FAA that the wake turbulence generated by a B757, in the landing config, is very strong, so it gets 'special mention'...

To clarify....perhaps you should go buy a scanner and listen to aviation frequencies....start at 121.7, or 121.9 (VHF band)....those are ground control frequencies. Ask t your neares airport, you'll find a pilot willing to provide the local (tower) freq, as well as the Approach and Departure control freqs...have him give you an old Jeppesen chart, after he's done the revision, before he throws it away....lots of good info there.....

reply to post by mirageofdeceit


mirage, (great avatar!!!)

second photo you posted, not a B747....as you prolly know. AirFrance A340.

There's a show, seen in the US, and in Australia, it seems....called 'Mythbusters'. They have devoted some shows to 'myths' about whether a taxi-cab actually got blown over whilst behind an airplane taking off....Turns out, it is an 'urban' myth...because... unless the taxi was driving across the end of the runway, the forces were not sufficient...

reply to post by ULTIMA1


ULTIMA, looked at your 'jet engine sim'....you do realize, don't you, that the effects of the thrust diminish by the square of the distance?

What I mean is, to the outsider, you see a tremendous drop-off of the thrust vector...

What's important, though, is how the engine affects the vehicle it is attached to. The energy imparted by the engine, propels the vehicle, at the moment by moment process, if you want to think of it that way.

In an airplane, there are other forces at work as well...go to a Flight School, and you'd learn about the 'four' forces....thrust, which we're discussing, and 'drag', commonly thought to be anti-thrust, but we'll keep it simple. There is always gravity (weight) of course, and finally...lift.

Lift is produced by forward motion through the air. Gravity can produce a forward motion through air, since we're talling about a wing producing such lift. Ever notice how a glider can stay aloft for hours at a time?

Other way, if you're not in a glider, to produce lift and not have to rely on thermals, is to have an engine. Thus, you have a powerful component of thrust, another source of energy besides gravity and thermal uplifts, and now you can design airplanes that are effecient in their own way...and can actually take you somewhere, rather than just be a toy (no offense to any glider pilots out there, I know it is a sport...an art...)

Back to point....the engine provides thrust, and the result of the energy imparted to keeping the airframe aloft is devoted to, well, keeping the airframe aloft!

If you want to examine the exhaust gas speed from an engine, whil the airplane is on the ground, then what you are looking at is....the exhaust gas speeds as energy is being exerted to move a mass (the airplane) from a standstill, to another speed.

If an airplane is taxiing, there is no need to advance the throttles, once motion is started. In fact, in some cases, just idle power provides too much 'thrust', once the airplane is in motion. We may have to 'ride' the brakes....but that's a poor idea, since it induces brake wear, and just adds heat, and we need those brakes in case of a rejected take-off.

There was a time, years ago, when some pilots would put a few engines into reverse, during taxi, to keep taxi speed down, without brakes....but, then there's greater potential for FOD....finally, and this is the solution today...taxi with one or more (if more that two engines) shut down. Saves fuel, prevents the fast taxi, and subsequent brake prob! Bingo!

At my airline, we were authorized for the single engine taxi, on the B737, but not the B757 nor B767. That may have changed in the last few years, I don't know. Reason is, there has to be a procedure, and a checklist, written for such conditions. AND, since we flew both the B757 and B767, and at times, a B767 would be so heavy that it would NEED both engines to initiate taxi, then there was no procedure to cover all contingencies, hence...all two-engine taxis was the rule.

[spelling]







[edit on 4/7/0808 by weedwhacker]

Originally posted by defcon5
You think that maybe again that could be because you’re dealing with two vehicles at the same level, AKA on the ground.

Last time i checked TAKEOFF meant you were in the air not on the ground.

Originally posted by weedwhacker
separation standards since it has be come to the attention of FAA that the wake turbulence generated by a B757, in the landing config, is very strong, so it gets 'special mention'...

Well you are talking about seperation at landing due to wake turbulence.

I was talking about seperation at TAKEOFF due to jet blast.


[edit on 8-4-2008 by ULTIMA1]