Unusual Vapor Trail In Dayton, Ohio

Unusual vapor trail causes speculation

A photograph taken in Beavercreek has some hoping it's proof of top-secret 'pulse jet' tests.

By By Jim DeBrosse

Staff Writer

Monday, January 08, 2007

BEAVERCREEK — A Beavercreek man's photograph of an unusual aircraft condensation trail has sparked a high-flying debate among scientists and aviation fans over whether the Air Force or NASA is flying an aerospace vehicle with an exotic new propulsion system.

The photo of the vapor trail, taken Nov. 10 by amateur meteorologist Bill Telzerow from his backyard, shows a distinctive "doughnuts-on-a-rope" shape.

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i would be very curious to know just who is the positive claimants in this " high flying debate " between scientists

my guess would be the usual idiots who call them selves scientists , but who need to get out more

i gave my opinions on this type of picture here several months ago

this picture is a posterchild , which re-enforces the opinions i prented in july

[edit on 8-1-2007 by ignorant_ape]

I cant find the picture of a vapor trail but I believe its from a scramjet.

a scramjet? really? i'll look it up. thanks.

Why would it be a scramjet that caused that, to me it looks alot simpler, air pressure differences. As pressure zones shift, they carry the vapor trail with them. In the end you get the same effect as you would when blowing smoke rings... a ring of vapor.

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Thats what I was thinking. Also, depending on the altitude, and the the weather that day, it could have been caused by wind. Just my two cents though.

NO !!!!!!

firstly - the only operational scramjet platform @ this time is the nasa unmanned test bed

secondly , if a real scramjet did fly over you @ hi mach speeds - you would hear it

why is it that people claiming that scramjets are buzzing them @ mach 5+ are too dammed dense to include the minor detail of sonic boom

" i saw a scramjet , and all i got was this crappy vapour trail "

Deleted. Double post.

[edit on 1/14/2007 by Tea]

It's a PDE, or Pulse Detonation Engine.

This is not a one-sentence post.

at the risk of repeating myself :

if you wish to claim that " it is a P.D.E. " then please provide some maths to back up this claim

it is a quite simple graph - to correlate " pulse frequency " against airspeed to give you the separation [ horizontal distance ] between each pulse

hint . @ mach five , with a pulse frequency of 1000 detonations / second , separation is just 1.65m

how far apart are the " donuts " in your contrail ???????????????

if you wish to debate this , fine

but please stop making one line claims of " its a pde "

I too get tired of those on this board who simply state "it is a PDE/scramjet/magic-carpet engine" with little to back them up, aside from a handful of pictures of some contrails blowing in the breeze. However, in this case it is not totally out of the realm of possibility. The Air Force Research Lab Propulsion Directorate (AFRL/PR) is HQ'd at WPAFB in Dayton, and they have been at the forefront of U.S. based PDE/PDC research from the beginning. The AFRL/PR also contracts out with some local technology firms, most notably ISSI (www.innssi.com...), which just happens to be located in Beavercreek, OH (Dayton suburb mentioned in article). I am unaware of any planned flights of their little 'PDE-dragster' as they call it, but I haven't been there for a year now and could easily have missed any announcements.
I highly doubt it's anything top-secret, since it was carried out during the day over a heavily populated area, instead of at night over a lake-bed out west. In any event, PDE's are by no means top-secret. There has been an enormous amount of white-world research done on them. Most of it is focused on replacing conventional constant-pressure combustors with pulse-detonation based pressure rise combustors. The idea being that a constant-volume process (PD-based) is inherently more efficient than a constant-pressure process (conventional). One of the primary concerns has been high-amplitude unsteady loads on a disk spinning at many thousands of rpm's in an environment well in excess of 2000F.
One mistake people tend to make when looking at these contrails is they immediately say the 'donuts' are too tightly or loosely spaced. Most PDE experiments being conducted these days are multitube experiments (those outside of the basic combustion phenomenon research done within the lab). Certainly any setup proving enough thrust (even a fraction of 'enough' thrust) would be a multi-tube setup. So if you don't know what tube setup was flying, trying to back-calculate the firing frequency is pointless. Sometimes they fire simultaneously and sometimes in sequence. The research community has not come to a consensus on what setup (if either) is best for whatever application.
All this being said, I too doubt it was a flying PDE test, simply on the fact that (to my knowledge) PDE's have not proven themselves all that reliable of a propulsion system, and as a result I would think any flight test would be conducted in the safe confines of Edwards AFB, not over a metro-area of a quarter-million people. Sadly, I do not have a counter-offer of what the apparent 'donuts' might be. The easy answer is 'some sort of aerodynamic phenomenon', but that's not really an answer at all, without being more specific. I'll have to defer to someone else's fluid mechanics knowledge on that.

The fact that it was over Wright Patt really doesn't help when it comes to trying to figure out if it was a natural phenomenon. People will automaticly come up with something. B-52 is out of the question. ... Im stumped. OH! Ill call up my dad's friend. He's a mechanic at Wright Patt. He might have seen something.