The purpose of such a configuration is not clear from a stealth point of view - most stealthy propulsion designs I have seen put the intake and exhaust on top of the lifting surface to shield them from ground-based radars.

From the pictures it is also evident that the craft was flying left to right across a south-facing field of view, at least from the illumination of the clouds (assuming mid-day).

Thus the craft's course is generally to the East. I am a glider pilot, and to my fairly experienced eye the cumulus clouds do not appear to be well-developed, and thus their bases are probably no more than 5,000 feet above ground.

Since the craft is well below them, I deduce it is at an altitude of only 2-3,000 feet. Given such a low altitude, it naturally led me to wonder if it was approaching an airport (in my sailplane I sure would be!).

Using Bing Maps, I found the location of the WalMart in Simpsonville, and sure enough only a few miles to the East I found Donaldson Air Center.

Examining the airport, I soon noticed a group of large structures at the south end, and using Bing's bird's-eye view, snapped an image of the biggest of them, also attached.

The logo on the side of the building probably tells us who made this little craft. Or does it tell us who it is spying on?

Follow-up...

A couple of things to clarify, and something new I have thought of too:

In my previous email, I said the clouds were not "well developed," but I realize that is glider-pilot-speak so let me explain.

Cumulus clouds are caused by the moisture in rising air condensing out at the "condensation level" or altitude at which the temperature goes down enough to attain 100% relative humidity.

Generally, faster rising air (like glider pilots want) produces clouds that are billowing and full, with well-defined flattened bottoms, not all ragged as in the picture.

These "well developed" clouds also tend to occur at higher altitudes than the ragged ones, closer to 10,000 feet or more, because the flow of rising air has more time to speed up when the condensation level is higher up.

Conversely, clouds that are not as well developed tend to occur at lower altitudes. That's why when I looked at the photos I instinctively felt the clouds were relatively low.

The other thing I forgot to mention is the identity of the Navy delta-winged plane that some commenters mentioned.

It was the McDonnell-Douglas A-12 Avenger II, a carrier-based stealth attack aircraft (not to be confused with the Lockheed A-12 spy plane, a close relative of the famous SR-71), and it was basically a perfect delta wing.

It was cancelled after years of delays and cost overruns.

<--- The attached picture is from Wikipedia.

Interestingly enough, it shows intakes on the bottom forward edge of the wing, but that was just a concept, and inlets tend to move around quite a bit as planes go from concept to reality, especially when there is a requirement for stealth!

Now the new idea:

I have been thinking about why a designer would want to place multiple engines inside a "box" along the lower leading edge of a delta wing, and I have a hypothesis.

I say multiple engines because the only way a box would not cause immense drag is if it were mostly comprised of inlets, which implies multiple small engines rather than (say) two large ones. One reason could be for the ability to hover!

If you have multiple engines that can direct their thrust downward, and they are spaced out both fore and aft, and side to side, you have a potentially very stable and controllable configuration for vertical takeoff and landing - VTOL.

The leading edges of a delta wing are perfect to achieve the required parttern. It would have lots of advantages over VTOL configurations that have to "balance" on one engine, like the Harrier, or the F-35B model of the Stealth Fighter.

Speaking of the F-35B, it has a very unique way of bending its tailpipe downward, by rotating two sections of it that are joined at seams that are angled.

Imagine a stovepipe that has two 45 degree joints in it to form a 90 degree angle. Now imagine that you could rotate the two "bend" sections in opposite directions.

If you rotated them both 180 degrees, the effect would be to straighten the pipe! Rotate them back, and the pipe bends again. It is hard to visualize, but I have seen video of it and it looks almost magical - and kind of creepy.

So imagine you have a delta with (say) six small jet engines set in the box shape under the leading edge, three to a side.

Imagine they have the bendy tailpipe of the F-35B. Through the use of differential thrust and differential bending, you have a stable and controllable VTOL capability.

Why put the engines in a boxlike housing? Stealth.

They can remain hidden inside the structure, just like the landing gear, and then "lowered" for landing and takeoff, again just like the landing gear is. That's why the landing gear on a stealth jet looks no different that on any other jet - it stays hidden inside the airframe, so it doesn't have to have a special stealthy design.

That also explains why the apparent indentation in the underside of the delta. It keeps the thrust clear of the plane when the jet exhaust pipe is horizontal.

Now here's the punch line. Who has almost all of the world's design and operational experience with those bendy tailpipes? Why, of course it is the maker of the F-35B, which also just happens to be the same folks whose logo is on that hangar at Donaldson Air Center.

What a coincidence.

Best Regards,

Ray Van Dune

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