posted on Jul, 4 2006 @ 09:37 AM
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
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 .