- 1 day ago
For educational purposes
Conventional airplanes need large runways for takeoff and landing, a limitation that worried defense planners.
As turbine engines became lighter, vertical take-off and landing (VTOL) aircraft became possible.
These craft could take off and land vertically, yet fly with the speed of jets.
Featured Aircraft:
- Ryan X-13 Vertijet
- Harrier V/STOL Jump Jet
Conventional airplanes need large runways for takeoff and landing, a limitation that worried defense planners.
As turbine engines became lighter, vertical take-off and landing (VTOL) aircraft became possible.
These craft could take off and land vertically, yet fly with the speed of jets.
Featured Aircraft:
- Ryan X-13 Vertijet
- Harrier V/STOL Jump Jet
Category
📚
LearningTranscript
00:01Hi, I'm Neil Armstrong. Join me for an adventure through time.
01:03This limitation concerned defense planners because runways and large aircraft carriers
01:10are vulnerable to attack. Military pilots dreamed of fast aircraft that could take off
01:17and land on small patches of earth. Helicopters solved the up and down, but their horizontal
01:25speed was limited. As turbine engines became lighter, a new breed of aircraft became possible.
01:33One that could take off and land vertically, yet fly with the speed of jets.
01:59Thomas Edison reportedly said, the airplane will be only half invented until it can take off and land without runways.
02:08The need for large runways is an obvious disadvantage. During wartime, it can be deadly.
02:19Designers envisioned flying machines that could take off straight up like a helicopter, then roar off like a jet.
02:25The aircraft would no longer need vulnerable airfields or cumbersome carriers.
02:31They might even be based on submarines.
02:35In the 1940s, when jet aircraft gave the promise of a thrust-to-weight ratio greater than 1 to 1,
02:42engineers realized that jet vertical takeoff and landing, or VTOL, was a possibility.
02:50If the engines could produce a thrust greater than the weight of the aircraft, they should be capable of lifting
02:56the craft vertically into the air.
03:03Aircraft companies in England and the United States were in the forefront of jet VTOL research.
03:10British engine manufacturer Rolls-Royce mounted two of its Neen turbojets inside a framework
03:16and modified the tailpipes to direct the jet blast downward.
03:21The four-legged contraption was called the Flying Bedstead.
03:25Its first flight in 1953 with Captain R.T. Shepard at the controls created a worldwide sensation.
03:33A vision of VTOL airliners eliminating the need for sprawling airports encouraged Rolls-Royce to continue its research.
03:49In the United States, Ryan Aircraft Engineers had been exploring the feasibility of a vertical takeoff fighter aircraft since the
03:561940s.
03:58Under sponsorship of the U.S. Navy and later the Air Force, the experimental X-13 aircraft was built.
04:08Early in the program, an Allison J-33 turbojet was positioned vertically in a test rig for control system trials.
04:16In remote-controlled flight tests, the vehicle hovered under its own power.
04:24A cockpit was added to the test vehicle, and Ryan's chief engineering test pilot, Pete Girard, climbed aboard for the
04:32world's first piloted jet-hovering free flight.
04:38A more powerful Rolls-Royce Avon turbojet engine was installed in the aluminum alloy and titanium airframe, and the X
04:46-13 VertiJet was born.
04:51It was designed to take off and land on an adjustable ramp.
04:55It was called, for obvious reasons, a tail-sitter.
04:59In 1956, with test pilot Pete Girard at the controls, the X-13 made its first manned jet VTOL hovering
05:07flight.
05:08A temporary framework was attached for vertical landing.
05:11The primary interest at this point in the testing was precise control at minimum altitude.
05:17Flying intricate patterns and spot landings within two feet became routine.
05:23In 1957, the X-13 made the first full VTOL flight.
05:28After moving away from the tower in a vertical hover, the X-13 pitched over into horizontal position,
05:35performed conventional flight maneuvers, then nosed up into vertical hover and landing.
05:41Over the next two years, two Ryan X-13 VTOL aircraft, with their distinctive delta wings,
05:49demonstrated high-speed flight, transitions, and vertical landings.
05:58Conventional aerodynamic controls only work when air is moving over the control surfaces.
06:04Forward flight creates this airflow.
06:06So the X-13 needed an additional control system for low speed and hover.
06:12This was provided by reaction-controlled jets located in the wingtips.
06:19While upright on its ramp, the X-13 hung by a nose hook suspended from a steel cable stretched between
06:25arms of the tower.
06:28The X-13 program failed to generate any production aircraft contracts,
06:33but it generated information and data of great value for more advanced VTOL projects.
06:39In France, jet VTOL research proceeded with a number of ATAR engine-powered aircraft.
06:45They attained hover, but not forward flight.
06:50Two other U.S. companies, Convair and Lockheed, were exploring VTOL flight powered by gas turbine engines.
06:58The Pogo had two contrarotating propellers.
07:01This was slower than jet thrust for forward flight, but more effective for hovering.
07:13The Pogo was tested extensively, but piloting difficulties killed the project.
07:18During vertical landing, the pilot was lying head down, looking back with your shoulder.
07:24These early jet VTOL aircraft were hard to fly,
07:27and the transitions between vertical and horizontal flight were difficult and dangerous.
07:32For VTOL aircraft to be practical, a new approach was made.
07:52VTOL research was driven by the military's desire for a fast, maneuverable aircraft
07:58that was not dependent on vulnerable airfields.
08:02After flight test, the shortcomings of the X-13's tail-sitting approach were recognized.
08:10The future lay in an aircraft that could sit in its normal horizontal position
08:14and take off vertically, a flat riser.
08:24After the successful test flights of its flying bedstead, Rolls-Royce went on to develop special
08:30lightweight jet engines that could be mounted in clusters for use on any kind of aircraft.
08:36The first use of this power plant was by short brothers in Harlan in the SC-1.
08:42Four engines were mounted vertically for lift, and one was mounted horizontally for propulsive thrust.
08:49In 1958, the short SC-1 became the world's first aircraft with separate lift and thrust engines to achieve vertical
08:58takeoff.
09:00The SC-1 was designed to be the forerunner of a single-seat fighter and a much larger VTOL airliner.
09:06But VTOL technology would develop in a different direction.
09:13Only Russia would continue to use separate engines for lift and horizontal flight on their Yak fighters.
09:20In 1953, with U.S. Air Force support, Bell Aircraft began the design of a testbed aircraft, the Model 65
09:29Air Test Vehicle, or ATV.
09:33Power was provided by two Fairchild cruise missile engines.
09:38Hydraulic pressure rotated the engines, directing their thrust downward for vertical takeoff and hover, and backward for horizontal flight.
09:49Bell's ATV showed the feasibility of jet VTOL aircraft.
09:54Research continued with the experimental X-14.
10:00In 1958, Bell Aircraft test pilot Dave Howe flew the experimental X-14 on a vertical takeoff followed by conventional
10:09flight, transition, and a vertical landing.
10:14What made the X-14 different from all of its predecessors was its use of deflected thrust.
10:23The X-13 had a single engine, with its thrust directed in one direction.
10:29To change from vertical to horizontal flight, the aircraft itself had to change position.
10:35The short SC-1 and Yak used separate sets of engines for vertical takeoff and hover, and for horizontal flight.
10:43The X-14 and the Harrier employed diverted thrust.
10:47Moveable nozzles direct the thrust from the engines downward for vertical takeoff and hover, and backward for horizontal flight.
10:56Thrust from the X-14's two small jet engines was deflected by a Venetian blind-like system.
11:03There was no need for hazardous tail-first landing, and no special landing rigs.
11:09The cockpit was open, with only a windscreen, no canopy.
11:13Weight restrictions ruled out an ejection seat.
11:16For pilot safety, flight testing was carried out above 2,500 feet or below 15 feet.
11:24Several models of the X-14 flew with enormous success.
11:29Intended only as a research vehicle, the X-14 later flew for NASA until 1981,
11:35investigating everything from electronic control systems
11:39to simulating the characteristics of a lunar lander in support of the Apollo effort.
11:50Sir Stanley Hooker used X-14 research data on vectored thrust to develop the Hawker-Sidley P-1127.
11:59The design employed a Rolls-Royce Pegasus engine,
12:03a turbofan whose thrust was directed from four nozzles,
12:07two at the front for fan air, and two at the rear for hot jet gases.
12:10The nozzles mounted under each wing rotated to change the direction of the jet thrust.
12:19Hovering trials began in 1960, with full VTOL flights the next year.
12:29A later version of the Kestrel research airplane
12:32became the first jet VTOL craft to enter military service.
12:39During this time, aircraft companies in many countries had VTOL projects underway.
12:45Ventures in Germany and France had some impressive successes,
12:49but a number of prototypes crashed, and the programs were eventually abandoned.
12:57In the United States, a number of VTOL technologies were being explored,
13:03including the Lockheed XV-4 and the Ryan XV-5,
13:07which employed jet fans mounted in the wings.
13:10Though there were setbacks, the concept proved workable.
13:14The project was later abandoned.
13:20Ducted fan technology was used in the Avro VZ-9 and the Piasecki Aerial Jeep.
13:26None of these approaches, however, proved as practical as the P-1127's diverted thrust.
13:33By 1960, many companies were planning jet VTOL prototypes.
13:40Few would actually develop into practical aircraft,
13:44but among those that did were the British Harrier and the Russian Yak.
13:49The Yak has two separate sets of engines,
13:53one for vertical and one for horizontal flight.
13:58Even though two models fly in the Russian Navy,
14:01it's an expensive, complicated, and an impractical design.
14:06The Harrier evolved from the British Hawker P-1127.
14:12It uses one engine, vectoring its thrust from horizontal to vertical.
14:21An elegantly simple approach.
14:27Further development of the P-1127 resulted in the Harrier.
14:32Though based on the P-1127, the Harrier was a new design,
14:37light and compact, with small, swept wings.
14:41It first flew in 1966 and entered service in 1969.
14:48McDonnell Douglas holds a license to manufacture Harriers
14:51for the Marine Corps in the United States.
14:54Their AV-8B Advanced Harrier has been developed
14:57to double the aircraft's weapons payload.
15:00Harriers normally operate in the STOL or short take-off mode
15:05with a vertical landing.
15:08Harriers have operated off of carriers from nations around the globe,
15:12including Britain, the U.S., Australia, Spain, India, and France.
15:18VTOL capabilities give the Harrier valuable flexibility in battle.
15:22It's designed to operate from small areas near the forward troops,
15:27as Harriers did in the Falklands campaign.
15:30In Desert Storm, Harriers played a prominent role
15:33operating off carriers in the Gulf.
15:37Neil flew a Marine Corps Harrier at Cherry Point, North Carolina.
15:44I'm here to show you the...
15:47These are actually the nozzles themselves,
15:50two on each side, the vector of the thrust.
15:52When they rotate down straight perpendicular to the ground,
15:56you can see how the airplane sits here physically.
15:59That's the way it'll sit in the air as well.
16:00So what we'll see is not 90 degrees, but 82 or so on the indication
16:06to make them 90 degrees in relation to the ground.
16:11That's how the thrust itself works.
16:13As far as the reaction controls,
16:16we've got our YAR reaction controls here,
16:20which, as you deflect the rudder,
16:23you can see that those...
16:26Yeah, they're...
16:27So they're really proportional to rudder deflection.
16:31That's right, sure are.
16:32Connected right...
16:32Directly proportional.
16:33Correctly.
16:34Down here, we've got the pitch reaction control in the aft,
16:38and it moves with the control stick again
16:41in proportion to that.
16:42It's proportional, too.
16:44I can show you the forward one, too,
16:46but you've got the YAR on each side
16:49that'll...
16:50as you move...
16:51So it's the same pedal movement as using the rudder,
16:54basically, to control that YAR.
16:55Same thing with the stick as far as controlling the pitch.
16:59Then we've got the roll reaction control over here.
17:03Up to about half stick deflection,
17:05the bottom part will open up on this side.
17:08Okay.
17:09Say we were trying to roll the other way, right?
17:11So this starts to open up when we deflect that aileron.
17:15Beyond half stick deflection,
17:16not only does this bottom one open,
17:18the top on the other side starts to open then.
17:21I see.
17:21It gives you more authority, so it gives you that,
17:24and you can see here how that would happen.
17:26As that opens on down, it starts to open up
17:29to give you more roll authority.
17:31Because if you start a roll, in some cases,
17:34you get to only a very few degrees.
17:37If you don't counter it immediately
17:39and do what it takes to stop it,
17:40it may be too late to stop that roll.
17:43So that's why they come up with all that authority for that.
17:46And then you've got the one on the nose as well
17:48for the other pitch.
17:50Now, this one and the one in the back
17:52are working always together?
17:54They work together.
17:55Always together.
17:55Not like aileron.
17:56If we're going half stick to pick the nose up,
17:59then this one's going to open up.
18:00If we're going forward stick,
18:02then that aft one will open up
18:03to pitch the nose down.
18:05Well, the only time this one isn't working
18:06in conjunction with the back one
18:08is when you have that situation
18:09to keep from blowing stuff up in the end.
18:11Right.
18:11If we've got that much trim down,
18:13even if we put in enough stick
18:16to normally open it,
18:17now it will not
18:18because we've got it set
18:19in that kind of setting.
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