Tuesday, September 28, 2010
This is a new one. This model flew yesterday in the UK. It's called the Demon UAV.
Here's a video of it flying.
So what's the big deal?
Well, it has no moveable control surfaces. That's right, no flaps, ailerons, elevators or spoilers. Just a wing, an engine and some holes.
First of all, the exhaust nozzle is moveable, so it can be vectored around to aid in directional control. Also, bleed air from an APU (auxilliary power unit, meaning a small engine) is blown through hundreds of tiny holes in the trailing edge of the wing to also help with directional control.
The military likes this because moveable surfaces like slots and flaps have edges and gaps, which are apparently total heat-scores when you are trying to have a low radar profile. Less edges to bounce off = more stealth, and that's generally what you are going for when you build a small UAV, most of which are used to spy on people in some way.
The advantages to this in a civilian application would be less moving parts, a stronger wing, less maintenance requirements and a cleaner wing which results in less drag, meaning less fuel burn.
You could control the boundary layer across the wing with air jets, which would also help change lift/drag characteristics for takeoff and landing.
We'll see if anything comes of this, but it sure does look promising. The one thing they will have to work out is how to control the airplane if the APU fails - presumably there'd be a way to store enough compressed air on board for a dead-stick landing. Presumably :) Now that I think about it, I'd also want some way to ensure that the holes don't get plugged with de-ice fluid in the winter... Clearly we are a few years away from hopping into a jet with no moving control surfaces, but the proof-of-concept is right there on Youtube, so it's not inconceivable that one day we might, assuming the advantages outweigh the hassles. I wonder how they'll rig the controls?
Flightglobal link here
Other link here