bipa said:
Quellish: I don't understand your point. F-117 inlets have a tight grate blocker/cover right at their aperture, while this device here is clearly more airflow-friendly, and designed for installation in a deeply recessed position inside the duct. Did you mean F/A-18E/F instead of F-117?
From "Radar Man", by Ed Lovick:
"My contribution at that time was to propose a special treatment for the engine inlets. It consisted of an “egg crate”[29] designed to operate as a collection of cut-off waveguides intended to prevent entry of radar waves into the front parts of the engines while allowing adequate air flow.
The smallest grid openings I was allowed by the propulsion engineers were too large to cause cut-off at the Gun Dish frequency. Their cut-off frequency was less than half the Gun Dish frequency.
At higher frequencies the grid would act like waveguides and let the energy go through, so we made the tubular parts of the inlet grids out of lossy materials. There was no metal in those grids. They were fiberglass with resistive coatings, and the resistive coatings were step tapered, not very conductive on the outside, and more conductive as waves progressed in, and finally fairly conductive. In this case the desire was to make the inlets blend into the surrounding absorber coated metal surfaces."
...
"One evening while the model was in the hangar, I decided to measure the resistivity of some of the tubes in the inlet grids. What we had done for the model was make, in effect, thin plastic shells that were coated with the resistive materials, and the shells would slide into a fiberglass replica of the inlet grid, so that we could take out those resistive card tubes if we wanted to—and I did."
The F-117 inlets, like the internet, are a collection of lossy tubes. Not a "blocker" like a Microsoft firewall.
So no, I did not mean the F-18E/F/X/M inlets.
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