Canadian Virtual Airlines
http://canadianva.com/forum/

Stealth - Why flat surfaces
http://canadianva.com/forum/viewtopic.php?f=2&t=591
Page 1 of 1

Author:  CVA1122 Ben [ Sat Feb 24, 2007 12:37 am ]
Post subject: 

When viewing a stealth aircraft or ship, they are frequently formed of composite materials at different angles.

The varying angles, they say, is to reflect back the radar in a random manner.

Would the round fuselage, with which they started, not better reflect back radar at random angles?

If angle of incidence equals angle of reflection, I would assume a rounded surface would be prefered to scatter the "beam".

Whaddya think?

Author:  katron [ Sat Feb 24, 2007 8:35 pm ]
Post subject: 

I agree Ben, but the way I see it is the entire length of the fuselage would have a strip a couple millimeters wide that would reflect the signal directly back to the radar station. Were as the different angles on the stealth will reflect the radar in every other direction except back to the radar station. I only see this working from a ground based radar looking up at an angle toward the aircraft. I think an AWACS type aircraft would get a different picture if he was directly perpendicular to one of those nice flat angles. This being because he is at the same height or above the stealth. Haviing stood beside one on a couple of occations has brought me to that conclusion. :O

Any other opinions on this subject :O

Author:  CVA1122 Ben [ Wed Feb 28, 2007 2:50 am ]
Post subject: 

Hadn't thought of the "strip" reflection from a cylinder. Good point, James.

However, some of those flat panels look like the size of a sheet of plywood. When the craft banks, surely those panels would be brought to bear.

I think the whole concept is kind of hokey, like the moon landing.

Author:  katron [ Wed Feb 28, 2007 1:32 pm ]
Post subject: 

hmmmm.....................banking,,,,,,,another good point.......I didn't even consider that one. :D

Author:  CVA9214 [ Wed Feb 28, 2007 3:54 pm ]
Post subject: 

Actually the best to be undetected with radar is to absorb the radar waves, not reflect them. The Flat surfaces of the stealth most likely aid in achieving the wave absorption. From what I remember in my military days the paint itself is called “IR paint” in fact even the camouflage paint of the vehicles works the same. I was always wondering years ago to try painting my car with this paint to see if I can blow by a Mr. Police man with the radar gun. :p

Author:  rabbitcancer [ Wed Feb 28, 2007 4:43 pm ]
Post subject: 

>>> agree Ben, but the way I see it is the entire length of the fuselage would have a strip a couple millimeters wide that would reflect the signal directly back to the radar station.

Bingo - and don't forget - it may only be millimeters wide but will also be at least 5-8 metres long..

...and Frank is right about the paint - although I'd have to disagree that the angle-flat surface absorbs...

The paint absorbs radar and disappaits heat (IR) and the angles reflect what's left IIRC...

Then you have doppler effects and continuous effects (plugging heavily-buried memory here) which react differently depending on what the aircraft is doing.

Doppler detects better on objects approaching or departing and will overcome absorbtion paint if the object is moving fast enough - therefore it is vital to reflect the waves in a different direction. This is evident on the nose and leading edge of the wings on the F117 which angles up/down and sideways.

Continuous radar tracks better when targets are tracking from left to right (or vice versa) but are better affected by absorbtion paint as they are less likely to be fooled by angles (i think).

Pilots also employ a radar avoidance method called 'threading the needle' which involves flying directly to and away from continous radar while maintaining static distance from Doppler (like a DME arc) to take advantage of each radar-type weakness.

Author:  CVA1409 [ Wed Feb 28, 2007 7:29 pm ]
Post subject: 

CVA9214 wrote:
Actually the best to be undetected with radar is to absorb the radar waves, not reflect them. The Flat surfaces of the stealth most likely aid in achieving the wave absorption. From what I remember in my military days the paint itself is called “IR paint” in fact even the camouflage paint of the vehicles works the same. I was always wondering years ago to try painting my car with this paint to see if I can blow by a Mr. Police man with the radar gun. :p

Apparently, the thing that speed radar picks up on the easiest is the headlights -- effectively nice reflectors pointing right at the reciever. I know for a motorbike that is about all they have to pick up on, due to the small front aspect cross section.

So, rather than paint, probably better to develop a radar mask for the lights. or take off the lights, but that is asking for another ticket that does not need radar!!

Author:  Rob Vanderkam [ Wed Feb 28, 2007 8:26 pm ]
Post subject: 

But who hasn't heard the urban myth of the AF pilots who drove their black cars at night with headlights off using night vision goggles - and leaving any radar gun-toting cop wondering if he'd had one too many the day before. The copy would see something on radar but not on "visual"... :cool:

Author:  CVA0014 [ Wed Jan 19, 2011 3:00 am ]
Post subject:  Re: Stealth - Why flat surfaces

Mythbusters tried driving a gokart in the dark using nightvision goggles. One major problem, no depth of field, it was tunnel-vision and they kept plowing into walls in turns.

They had binocular eyepieces, but only a single receiver up front. Basically you need dual NV goggles, one for each eye.

Author:  mhooner [ Sat Jan 22, 2011 11:19 pm ]
Post subject:  Re:

rabbitcancer wrote:
>>> agree Ben, but the way I see it is the entire length of the fuselage would have a strip a couple millimeters wide that would reflect the signal directly back to the radar station.

Bingo - and don't forget - it may only be millimeters wide but will also be at least 5-8 metres long..

...and Frank is right about the paint - although I'd have to disagree that the angle-flat surface absorbs...

The paint absorbs radar and disappaits heat (IR) and the angles reflect what's left IIRC...

Then you have doppler effects and continuous effects (plugging heavily-buried memory here) which react differently depending on what the aircraft is doing.

Doppler detects better on objects approaching or departing and will overcome absorbtion paint if the object is moving fast enough - therefore it is vital to reflect the waves in a different direction. This is evident on the nose and leading edge of the wings on the F117 which angles up/down and sideways.

Continuous radar tracks better when targets are tracking from left to right (or vice versa) but are better affected by absorbtion paint as they are less likely to be fooled by angles (i think).

Pilots also employ a radar avoidance method called 'threading the needle' which involves flying directly to and away from continous radar while maintaining static distance from Doppler (like a DME arc) to take advantage of each radar-type weakness.

Hey Devon, good to see you're still alive and kicking. :D

Author:  Rob Vanderkam [ Sun Jan 23, 2011 12:14 am ]
Post subject:  Re: Stealth - Why flat surfaces

LOL - check the date!

Author:  mhooner [ Sun Jan 23, 2011 11:47 pm ]
Post subject:  Re: Stealth - Why flat surfaces

Ouch.
Asleep at the wheel again. :wink:

Page 1 of 1 All times are UTC
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/