Slashdot Mirror
Push a Button, Land on a Carrier
sane? writes "Putting an aircraft down on a carrier in bad weather is the stuff of melodramatic Hollywood films. Automated systems for conventional aircraft and big carriers has been done for a while, but getting a hovering Harrier, helicopter, or future JSF to land on a pitching deck of a smaller ship is a different matter. This week QinetiQ demonstrated a complete autoland - a significant step towards making the future JSF work."
I don't see a lot of geek content here, just American type propaganda.
Well, a British aeroplane (Harrier), a British company (Qinetic), a British ship (HMS Invincible), carried by a British news service (BBC). Damn this Americanisation. Oh... what language are these posts in, English?
Plus its pretty cool, IMHO, that a computer can do this given the huge difficulty and inability to simplify the process (wind, gravity, thrust) into simple mechanics.
Even a single seater fighter is a big beast, compared to say, a family car. If you've ever seen a Harrier thump down on the deck of a carrier, you'll see that the suspension gives considerably more than 10cm as the plane makes contact. I think 10cm is more than good enough - certainly better than any current pilot, and they seem to do OK.
F-15's don't fly off carriers.
so you can 'bolt' a broken wire or hook
bolter
When landing a harrier on a pitching, rolling aircraft carrier deck, 10cm doesn't make any difference at all. In fact, it's pretty much a precision touchdown.
"I'm not impatient. I just hate waiting." - My Dad
Despite all the skepticism being bandied about military technology on this site, automated carrier landings are not new. The first fully automated landing on an aircraft carrier took place on Aug. 12, 1957, when an F3D Skyknight was landed on USS Antietam (CVA 36) at sea off Pensacola, Fla., by the Automatic Carrier Landing System (ACLS). That's right, over 40 years ago. That system is still in wide use today, and is only now slowly being replaced by the JPALS (Joint Precision Approach and Landing System) system which uses GPS instead of the radar used by ACLS.
The QinetiQ system described in the article (which is itself a component of JPALS) is remarkable in that it automates vertical landings. I'm kind of uncertain as to why that had never been done before, though I think it has more to do with the much lower level of interest, and therefore funding, than because of any technical challenge.
The basic problem is that a Harrier has more major flight controls than the pilot has hands. There's a nozzle angle control and a throttle control, along with the usual stick and rudder pedals. VTOL operation requires coordinated operation of the nozzle and throttle controls. Both have significant lag. That's a tough control problem, worse than a helicopter.
Everything has been tried. Better pilot training. New flying approaches. Simulator training. A redesign (the Harrier II). Stability augmentation systems. Avoiding VTOL whenever possible. Harriers still crash a lot. (The Harrier has a good ejection system, so the pilots usually survive.)
One of the stability augmentation systems was the VAAC Harrier Study. This was an experimental effort to use computer control to get the three inputs that affect longitudinal stability (stick, throttle, and nozzle angle) down to two. This was supposedly successful but was not deployed.
This new thing seems to be a further step in that direction.
That's a misconception. They always talk about how hard/impossible a plane would be to fly if it weren't for the computers.
Unstable in the aviation world does not have the same meaning that non-pilot types give it.
Stable means the design causes the plane to try to return to it's orginal attitude after disturbed by: wind, an input by the pilot etc. So if I bank the plane to turn, when I let go of the controls eventually the plane will level itself...most of the time. In certain situations even stable designs become unstable and will not self recover. For training, safety sake, and to reduce pilot load this design makes sense, but high performance this design will never be.
An unstable design if put in the same situation, banking the wings and then letting go of the controls will result in the plan most likely to either hold that position or to continue to steepen the turn. During manuevering this is very desireable, but eventually without input by the pilot the plane will get itself into trouble.
Now jump in with electronic flight control systems. They can duplicate the same built in stability a Cesna has and make the plane easy and docile to fly, or I can press a button and put it into a high performance moden and be highly manueverable. I can have multiple modes each being usefull in certain situations. For example I can have it dampen airframe oscilations that can lower the life of my airframe, and those same sensors can be used to detect and put corrections in for wind to help me hold a course. I may simply want it to hold the plane in what ever attitude I put it in so it flies more like a plane in a video game, (even unstable designs will have some attitudes it will try to correct itself in so that can hinder you) Add in an autopilot and a GPS and now I can simply give the plane waypoints to fly. Throw in a few more tricks and I can get the plane to take off, fly to a destination, and land in weather most pilots would say forget it. I can turn off nearly all the systems and fly the plane manually without much difficulty, but my life would be a bit more difficult.
This is my take on flying: flying a plane is alot like driving fast in light traffic in a manual car, in bad weather, listening to 4-5 passengers talking, talking on 2 cell phones to different people every 10 minutes, looking at a map, and of course trying to keep the car on the road, a road that you may or or may not even be able to see, and finally a road that can be driven in any direction at multiple altitudes.
If you were a military pilot add in freaks shooting at you while doing all these things.
These systems definitely improve the pilots control and precision and give him a chance to set down a few of the items they are juggling to be able to rest or concentrate on fewer things. This expands the envelope a pilot can opperate in.
I'll give you one point though. You are correct in most modern aircraft if you were to suddenly take away all of the electronic flight systems the plane would fall out of the sky, but to get all those systems to shut down at once (most primary systems are at least triple redundant)usually means something so drastic had happened that the plane would have come down whether or not those systems were functioning.
Note: The first linked pic looks like an A-10 rather than what it is labeled as (F-15)