Viper RCS (Radar Cross-Section) is ?

[Tom and Vipers]

I remember long ago that either a C3 or C4 Corvette was only observable with 500 ft. of a Police radar.

Other cars were 1000-1500 where tractor trailers were "thousands."

The reason for the Corvette was the sloped radiator which basically reflected the radar in a different direction than back to the transmitter.

Stealth technology is tricky. The difference between a 1 meter sphere and the same sphere with a dime laying on top of it is a number of orders of magnitude.

The Viper may be very good because there isn't a straight surface anywhere on the car. Right angles are the kiss of death too. Naturally, the seams between panels are quite important too. ...and as far as the radiator goes, I'm not sure what is really required.

...but it would seem to me that the Viper may have reduced observability.

Anyone see any tests of this?

 

[joe117]

As a long time EW guy I can tell you a little about this. Your headlights will be a large reflector. If they are turned round as in a Vette, a smaller RCS will result. Radiator angle is probably not much of a factor. The Frequency of a Ku band radar is 24Ghz with a wavelength of about half an inch. Any conducting surface that is at least .25", or half wave, is going to be a good reflector. The radiator surface itself is a reflector. If it is angled it will present less area to the radar but it will still be a major reflector at Ku band. It won’t reflect the signal away when angled because it is not a solid reflector. The Viper body is probably transparent to the Ku signal and so the gap between panels is meaningless. Picture the car with no plastic body at all. This is what the radar sees. The bottom line is that the microwave reflection from the optical reflectors, that is, headlights, hi/low, fog lights, even parking lights, will be very very large, so large that there will be plenty of reflection for the police radar’s, high gain antenna, aimed right at you. There is one thing that you might do. A conductive wire screen mesh, where the mesh size is less than 1/10 wavelength will act as a solid reflector, no microwave will get through. A mesh like this placed over the optical reflectors will let some light out and keep the optical reflector from being such an RCS hotspot. This will reduce the overall RCS of the car quite a bit. The screen would need to have openings not larger than .05” for this to work at Ku band. The screen will reflect microwave but not with the large retro reflector effect of the headlights. A normal wire screen of this size wouldn’t pass much light. If the screen were made of metal plated strands of fiberglass, like chaff, it would work and be hardly noticeable.
If anyone would like to start a company selling this product, I'll consult for you.

 

[RonC]

I went back to my old textbooks on advanced electromagnetics (hoping my advanced degree could help). Unfortunately all the equations for electromagnetic reflectivity seem to dwell on long metal cylinders! Can we model the Viper as a long aluminum cylinder with wings?

Ron

 

[joe117]

I need the fellow who sent me an email about this to contact me again. I lost your address.

 

[Guibo]

RCS? It's almost nothing!

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Larger pic:
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[Newport Viper]

My girlfriends Jeep Liberty must have a large cross section.

87 in 65 on the 73 today. How embarrassing, not even in the Viper!

 

[Jack B]

I have had the same cop shoot me twice with a laser in the same location. Both times I was doing 85 in a 55. In each case you could see the confused look on his face as we passed. He was shooting across four lanes so he did have a poor angle and there is no front plate.

Since the radar or laser is reading a trigometric relative speed they cannot read your dead ahead speed unless they are straight ahead of you, as your angle to the radar/laser increases, the reading (less) relative to actual is exacerbated.

 

[Miles B]

Do they really have to hit your front plate? I wouldn't think they could do that with any car... it moves around so much? Like trying to shoot a sparrow with a handgun.

???

 

[joe117]

They don't have to hit your front plate with radar. The radar beam will cover your whole car and more. The biggest reflection on a Viper will come from the headlight pods. I have not tested this but it is the major reflector on most small cars.