reply to post by ashwhy
Hereby nominated for the Necromancer of the Day award. Forum zombies won't spawn themselves, you know.
Sorry - had to poke some fun.
Anyway - the idea is not all that new. By blasting jets of air along the trailing edges of a lifting surface, you adjust all manner of things and can
control the chaotic boundary layer. In theory - you can maintain control through an angle of attack at 90 degrees. Reality will knock that down to a
lower number around 75-80, however.
It all has to do with air pressure and fluid mechanics. In normal lifting surfaces, air along the curved surface begins to slow down and 'sluff'
off of the wing surface. This is, generally, bad for more than a few reasons. First, it radically impacts lift. Second, since most of your control
surfaces are at the rear of your lifting surface (wing), you want air flowing smoothly over those surfaces to impart reliable, consistent forces to
control your aircraft.
Several methods have been used to control this - 'belted' wing surfaces have been tested - essentially a conveyor belt built into the top of a wing.
This helps bleed off low-energy air and keep higher energy laminar flow close to the wing. A fluid dynamics book I have details some studies where
some very high angles of attack were achieved with no departure from laminar flow. Granted - actual incorporation into servicing aircraft was
Other ideas included porous materials that would generate a negative pressure and thereby siphon off problematic pockets of air. The book indicated
there were studies and even military applications of this sort of thing - but I do not recall any direct citations or coming across any similar
This is just a little different twist to the same concepts. By artificially inducing departure at specific areas of the wing, you can very
efficiently influence the flight of the aircraft. It's not thrusting with the jets of air, it is merely disrupting the standard airflow, and when
that happens, the aircraft behaves very similarly as though a control surface was moved or the wing, itself, changed shape.
A similar system was dreamed up by myself using electro-active polymers to create an entirely adaptable airframe (though far more extreme of an idea
than puffs of air). I later came across a similar idea in Dale Brown's Air Battle Force series utilizing micro-hydraulics embedded in the skin of an
aircraft, allowing it to 'swell' and 'shrink' its wing surfaces, and achieve a wide range of control and trim efficiently.
Anyway - the point is that there's a lot of ideas floating around out there on how to control a plane without flaps/elevators/ailerons/etc. Good
find on this one, I never would have thought we would see this method of flight control prior to the others - well, aside from strategic placing of
jet engines or some crazy idea of venting jet-blast through the trailing edges of a wing (the type of thing I think about trying). Though I contend
this would have been fine started in a new topic - it is no biggie.