Donut on a rope contrails , the physics precludes Aurora ?

Donut on a rope contrails , the physics precludes Aurora ?


The “ donut on a rope “ contrail is commonly touted as evidence of AURORA or other claimed hypersonic craft , employing radical new engine technologies

Here is a “ typical “ picture claimed to be an AURORA trail



But to create the “donuts “ at the separation seen in the pictures of the contrails claimed to be of AURORA , The craft would have to have a velocity and engine exhaust pattern totally incompatible with the AURORA`s claimed characteristics

PDE engines of a type that would be suitable for an AURORA craft will reportedly operate @ “ 1000s of pulses / second “ according to wikipedia

Even at a “ conventional “ 250 pulse / sec an engine would , at MACH 5 leave < 10M between each pulse .

For a “ true “ PDE it gets far worse .

Another side effect, not yet demonstrated in practical use, is the cycle time. A traditional pulsejet tops out at about 250 pulses per second, but the aim of the PDE is thousands of pulses per second, so fast that it is basically continual from an engineering perspective. This should help smooth out the otherwise highly vibrational pulsejet engine -- many small pulses will create less volume than a smaller number of larger ones for the same net thrust. Unfortunately, detonations are many times louder than deflagrations

Even selecting a “ low “ number of 1500 pulses / second , The “ aurora craft “ @ mach 5 would have a separation of just 1.1m between pulses , @ M10 , just 2.2m . even @ mach 20 it would still “ only “ be 4.4m

viewed from the ground – it would be impossible to distinguish each pulse .

To an observer the exhaust would be un interrupted , As incidentally would the sound signature – 1500 individual detonations / second would be perceived as a single continuous roar . Even the report from a minigun such as the US M134 , firing @ 6000 RPM , only 100 shots / second is a single ripp , individual shots cannot be identified

So whatever “ donut on a rope “ contrails really are – its highly unlikely that they are the signature of a hypersonic craft , using a revolutionary PDE or similar experimental engine .

APE OUT

I’m afraid you have overlooked one small but important detail, atmospheric conditions, you know, moisture, wind, air pressure, etc... Now if you were to take a picture of an "AURORA" contrail for example immediately afterwards then you probably would see a straight line, but how often does that happen? Since most pictures of alleged "AURORA" contrails are probably taken several minutes, if not more, after the sonic booms are heard one could argue that by that time atmospheric conditions have interacted with the contrail and caused the "donut on a rope" pattern to be visible from ground level.

I've seen, heard, and felt this thing. Sitting in my ofice at work bsing with some pilots t the airport, which rarely recieves turbine traffic, we hear a VERY low rumble, and the windows begin to shake. We go goutside to spot the craft, and hear a loud, low, rolling continous sonic boom type of sound. Looking up, we saw the classic "donuts on a rope" from east to west, a bit north of the field and town, out over the desert. We caught the very end of he contrail being formed and whatever it was, it was moving faster than i've ever seen anything move.

What was it?

I don't claim to know, i only claim i saw and heard this contrail being formed. And no, i don't have any pics, never saw it again, but i heard the same sound 2 other times in the same area.

Originally posted by WestPoint23
I’m afraid you have overlooked one small but important detail, atmospheric conditions, you know, moisture, wind, air pressure, etc... Now if you were to take a picture of an "AURORA" contrail for example immediately afterwards then you probably would see a straight line, but how often does that happen? Since most pictures of alleged "AURORA" contrails are probably taken several minutes, if not more, after the sonic booms are heard one could argue that by that time atmospheric conditions have interacted with the contrail and caused the "donut on a rope" pattern to be visible from ground level.

One small but important detail is that if atmospheric conditions could transform a straight line into such a contrail, it could also happen to straight contrails from other, "normal" aircraft such as big jetliners. So wishful thinking from your part. Donut on a rope contrails can indeed be caused by big jetliners as well depending on atmospheric conditions. See also ATS very own TinWiki site:

Aurora contrail
The Aurora's contrail is rumored to be a long, slow-dissipating trail with 'rings' or 'loops' around it, called a Donuts on a Rope trail (Also Donuts-on-a-Rope), Donuts trail, Rings on a String, Donuts on a String, Loops on a String and Rings on a Rope.
However, this trail is made not only by the Aurora, some sites speculate. Dreamland Resort (See external link) give examples as to aircraft that make these contrails that we see everyday, suggesting that the contrail could be made by any aircraft with the right weather conditions.

A Donuts on a Rope contrail created by a normal tanker aircraft

Umm, simply no, since an "AURORA" contrail would already have a "donut on rope" contrail, atmospheric conditions would not be creating anything, they would simply disperse it to the point where that pattern is visible from the ground. Now, this cannot happen with a regular straight contrail, at best what atmospheric conditions can do to a regular contrail is chop it up or break it, if you will, and make it look sort of funny, in fact I saw one just like that the other day, but that’s not a real "donut on a rope" contrail and neither is the one on your picture. This on the other hand…




[edit on 5-7-2006 by WestPoint23]

Well, actually, I've seen many craft create ones similar to your piccy there. The one I took up there is the more common one that people see after sitting in a windless sky for five-ten minutes. Though it did look quite abit like the classic donuts-on-a-rope, even with little wind, it could look like anything. And may I mention that the craft that made that was a MD-80, and not in any way an Aurora. I've seen donuts trails of all kinds from tankers, C-130s, and all kinds of Boeings and every day craft.

In other words: The Aurora could possibly make a Donut trail, but so do other craft.

I suggest you go to Dreamland Resort.com and look up the donuts on a rope article.

oh, and alot of regular straight trails I've seen have become donuts trails after about ten minutes or so on a usual windy day.

Originally posted by WestPoint23
I’m afraid you have overlooked one small but important detail, atmospheric conditions, you know, moisture, wind, air pressure, etc...

IMHO no i have not , if you want to claim that weather conditions mutate the trail , please explain how , this :

))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))

turns to this :

)................).....................) ....................)................)................)

the main "evidence "behind the " donut on a rope " = aurora claims is the assumption that aurora uses a PDE engine and the visible serperared " donuts " are the residude of INDIVIDUAL pulses from the engines

this is total nonsense , for the reasons i detailed in the 1st post .

the " pulses " would be identical , linear and very tightly spaced , the idea that some weather condition could selectivly delete a number of the donuts , and leave others intact is absurd .

upon reflection , i could have worded the title better -- but now my post has been quoted from -- i cannot edit it

i guess my position should be that the AURORA is not a definitive answer to " donut on a rope " trails as widley claimed

and that the reasons why aurora is credited with being the creator of " donuts on ropes " trails are false .

[edit on 6-7-2006 by ignorant_ape]

So what does fly fast, emit a gnarly rumble, and streak across the sky leaving a string of pearls? Something does. My sighting wasn't weather effects, i saw the end of it being formed and it was laid down with donuts on the rope, really fast.

All of this is really splitting hairs.

If it's a PDE of the caliber being determined the 'most efficient' - then it would be no different from any other contrail - I see aircraft all of the time that are leaving contrails at VERY high altitudes (above 30 thousand) and going pretty dashgum fast. Could that be them?

If the donuts on a rope can form from atmospheric effects - then arguements for or against the Aurora's creating them are irrelivant.

We're assuming that we know the Aurora is using PDE, we're also assuming it's using one with the itnigion rate described - which would be rather hard to achieve AND that that is the most efficient way to do it. Since flight dynamics change greatly as speed increases - so will the dynamics of an engine and what make it efficient.

We're basing on too many assumptions and not enough facts.

We're also looking at the fact that strange atmospheric forces can cause a normal contrail to 'mutate' into donuts on a rope quite often - so this also begins to negate the arguement that the entire subject is relative.

If you want my opinion - a PDE is a waste of time and effort - the Aurora is using scram or fusion. - and Fusion could be done in a pulsed manner, to keep from vaporizing system components.

Or it's Santa Clause flying a kite to get us talking about strange triangular objects. The sky is not the limit, here.