“There is no “one thing” that encompasses radar stealth. It’s a combination of things to reduce radar return signature. Among those are overall shape, material composition, material coatings and on-board electronic countermeasures.”
There are three main elements to low-rcs stealth platforms Size, Shape, Coatings/Treatments. To the extent that you succeed in integrating all these in a successful platform you are as much controlling the signature as you are reducing it.
You still have visual, acoustic, IR to worry about.
Based on pictures of the Ximango, I’d say it’s not particularly stealthy in RCS - at least in the military sense. as a glider, it no doubt is stealthy acoustically, maybe somewhat in IR, and perhaps visually as well. Important for a drug interdiction mission, more than RCS.
And, you would be wrong. Actually, our military is VERY interested in what we've shown them so far. In addition to consulting on this project part of the reason why I'm involved is because I've owned a Ximango for about 5 years. First hand experience tells me without the transponder squawking it has an exceedingly low RCS unless oriented directly nose-on at the radar transmitter. I've been a number of places in it where I've had to deal with military ATC to get clearance through restricted areas (i.e., Giant Killer, Pensacola, etc) and they don't "see" it any better than civilian systems. Last year a friend who also owns a Ximango were flying cross country together out to Nevada. Several times in our trip ATC commented that they were only painting one aircraft. Only later did we recognize that his transponder wasn't working. We'll be doing some range testing shortly and I'll have the actual numbers.