This is sick. Who knows if it will go anywhere, but glad the government still finds ways to spend money on expensive experiments. It pushes collective science forward.
So true. RIP "invisible hand" efficient market hypothesis.
Don't get me wrong, I agree with you! I'm also happy that we use taxpayer money to subsidize corporate R&D, but let's not suddenly sugarcoat that fact (or forget it entirely) the instant our thoughts shift to economic policy.
In the VC world, your one huge success needs to cover the cost of the other nine failed bets. When taxpayer-funded research gets "commercialized," this rule is quietly forgotten. That's the biggest subsidy giveaway right there.
Smith didn’t claim that an “invisible” hand was a sole or even predominant mechanism, just that it could apply to specialization. In fact at a microeconomic level Coase’ “Nature of the firm” says the opposite is true, and he’s as mainstream as you can get.
In general (this is not a comment about you, schiffern) most people who exalt Adam Smith have never read his book and would be shocked that he was such an enthusiast for welfare, regulation, and government intervention and support.
I think the fact that we have tens of companies making different sugar water is proof that capitalism allocates capital in ways that is useful to humanity! Sarcasm aside, I don't actually have a better solution.
A big part of the idea is the have a plane the models what humans will eventually use, so that any test results they get can more easily translate to eventual human-carrying flights. It's not a mistake that the speed, weight, and shape closely match what fighter pilots train in.
But if you look at most UCAVs, they mostly have 'broadly normalish' looking shapes. XQ-58 for example is relatively conventional looking.
I think the reality is that there are a lot of advantages of the 'normal' airplane shape that removing the pilot doesn't drastically change. Warplanes are going to have some pretty high mass, kinda bulky thing to manage (especially engines and radar). Keep those close to the center of mass is just... sensible. Since your flying forwards, that biases you towards either a tube with wings or flying wing.
Pure flying wings are apparently kinda annoying to deal with - especially when what you're working on is trying to innovate in autonomous systems, maybe you don't want to spend extra effort trying to conquer too unconventional structural layouts.
Actuators without moving parts would be great to have on civilian airliners, too! Fewer moving parts means fewer chances of something to break, fewer parts to service when landed, less weight to carry, likely cheaper to produce. Wins all around.
A smaller plane maybe could be flatter, not required to accommodate a pilot in a sitting position.
But the plane likely still needs to have a shape similar to "normal" planes. One reason would be to experiment with one thing at a time. A classic fuselage + wing + tail arrangement is well-studied and understood; what remains to study is the unusual actuator system. But getting something non-traditional like B2 to fly is a challenge in itself; with experimental actuators, it's even harder.
For subsonic planes, the traditional airplane shape is likely close to optimal, since birds, especially gliding birds like eagles, use a very similar arrangement for millions of years.
One outcome of the experiment is already certain: the demonstrator will live on forever in "ugliest plane" collections. And as usual with the constituents of these lists, it's not entirely without appeal. You almost want to pet them for providing consolation.
There are valves without wearing or rubbing parts. A solenoid that moves a ball back and forth can open or close billions of times without any appreciable wear.
Moving control surfaces are simpler, from an engineering perspective.
I'd worry the failure modes of a pressurised air system, which are surely more numerous than a simple mechanical flap. Any failure would be catastrophic to the airplane.
You're making very conclusive / "just so" statements; are you an engineer? Because the moving control surfaces have their own issues; actuators, hydraulics, wear and tear, etc. This looks (and I'm no engineer) to be mechanically simpler, lighter, fewer moving parts, etc.
Of course, there's bound to be a caveat or ten, since else why wasn't it tried earlier? It doesn't look technologically advanced, doesn't look like it couldn't have been done decades ago.
Yes fun joke, but it's literally one plane out of thousands produced and everyone survived. FWIW, the bleed air systems kept working perfectly so they had plenty of pressurized air inside.
All modern fighter jets have relaxed stability and are controlled by complex fly-by-wire systems with precise hydraulic actuators moving huge multi-purpose control surfaces (e.g. stabilators, elevons, flaperons). "Simple" has left the chat a long time ago.
Looking at demonstrations and on-the-ground displays of these mechanisms leaves me absolutely in awe and terror. I really can't imagine putting my life in the hands of the thrust vectoring mechanisms. It's really something.
They're amazing but they violate the intuitive moving-parts-to-risk count.
Boeing 747 stabilizer trim is achieved by rotating the entire tailplane by up to 15 degrees. The elevator is much smaller (less than 1/3 the area) and is deflected by a smaller angle.
That's some serious force you'd have to apply with those air jets either throughout the cruise phase or takeoff/landing.
Passenger jets need it because the center of gravity can vary a lot depending on passenger and cargo loading. A spy plane could probably be built with almost zero variation, with some careful fuel tank management.
Positioning of nozzles in the video suggests they're experimenting with a BLC system, not just nozzles placed in the extremities like in the Harrier jets.
Maybe the horizontal stabilizer trim can be replaced by a mobile weight inside the plane (moving along the front-to-back axis), that allows "trimming" the position of the center of mass.
Funnily that's applicable to balancing unswept flying wings, as all high lift/low drag airfoils are unstable in pitch (though many are stable for inverse flight, i.e. if you get scared you'd have to turn upside down and are suddenly stable).
I'm general, moving cog is potentially lossless, putting control surfaces into the airstream will always add drag.
> Is there a way to take off with only active flow control?
I think so? Of course you still need steering control on the gears, but I don't think you mean that.
Maybe you are thinking similar to how I was thinking about airplanes before I started learning to fly. I was thinking that taking off is surely some deviously hard trick, since you go from non-flying to flying. But in reality airplanes are designed to "want to" fly. You just apply throttle and it kinda happens almost on its own. In fact you need to push the nose down a bit so it doesn't fly up before you picked up enough speed to do safely. (I understand that this description might not be true for every airplane, but the general idea that take off is not that hard is usually true for all of them.)
Yes, this is explained in the video and article. The prototype will have both control for comparison study and baseline data. i.e. only manipulating yaw with air.
Conventional moving control surfaces also have reduced effectiveness at slow speed. The thing is, though, that an airplane will not be flying unless it is traveling at a speed sufficient for it to create lift at least equal to its weight, and the forces needed to control the aircraft are a fraction of that (you can get an impression of the size of that fraction by comparing the area of the control surfaces to the area of the wing.)
I doubt DARPA would commission this aircraft without having already established that it is likely to work, and it will have conventional control surfaces as a backup.
I am curious as to whether they intend to keep conventional moving surfaces for trimming in pitch, especially if they are going to give it flaps.
It could be better than conventional controls at low speed, dependign on how strong the pressurized air jets are. A bit like reaction control thrusters on a spacecraft?
I wouldn't be surprised if there are even control forces at zero airspeed, with just the air jets acting like reaction control thrusters.
Or it might be more like active boundary layer control, just nudging the passing air stream one way or the other with the air jets.
