the ZOO of Chinese Military Drones.
No other country has invested in drones as much as China did.
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LearningTranscript
00:00Hey, in the last few weeks we have discussed quite a lot about Chinese drones and there
00:06has been quite a lot of interest, so I thought that I could edit together all the material
00:11that we have produced in one of those long format videos that many of you actually do
00:17appreciate.
00:18So, here it is, the zoo of the Chinese drones.
00:21Enjoy!
00:22It is a dark night and visibility is poor in the Eastern Pacific.
00:29A group of US destroyers led by the USS Kidd is training about 200 miles off the Californian
00:36coast.
00:37So far it has been a relatively standard operation, but at 10 pm everything changes.
00:45Lights start appearing around the ship.
00:48They keep their distance but move around the vessel and can keep up with the ship's speed.
00:53They are visible to optical sensors and the gigantic SPY-1 radar can track them.
00:59When one gets a bit closer, the crew gets a glimpse of a quadcopter, but the duration
01:05and the speed performances are beyond what can be expected from a commercial drone.
01:11The USS Finn, another Arleigh Burke destroyer, reports similar sightings.
01:16And then it's the turn of USS Russell and the USS Rafael Pereira to report in.
01:23All the ships are now engaged and their first reaction is to gather all the intelligence
01:28possible about these UAVs.
01:31What they do not realize immediately is that they are the object of intelligence being
01:37gathered.
01:43No, I'm not launching a new technotrailer series.
01:46What you've just heard is a very short account of what happened to these ships for two nights,
01:52the 14th and the 15th of July 2019.
01:57Only after the fact and after a lengthy investigation spanning multiple years, it became clear that
02:03the drones were coming from a merchant ship that could be linked to the Chinese Armed
02:08Forces.
02:09Well, this link is not 100% sure, but there is a message here.
02:14Welcome to the new Cold War.
02:35So the Chinese seem to have made a strategic choice to develop their unmanned capabilities.
02:40They have invested heavily for over a decade, from cheap and expendable commercial quadcopters
02:46to high-altitude long-endurance drones.
02:49They also filled the first operational stealth UCAV, the GJ-11 Sharpsword.
02:56It is possible that the GJ-11 was inspired by US drones captured by the Iranians in 2011,
03:04but since then the aircraft has evolved a lot and it entered operational service in 2019.
03:12For now it can't operate from carriers, but there are definitely plans to create a naval
03:17variant to be operated from the Type 003 carrier and potentially from the Type 076 amphibian
03:24landing ships.
03:25But the GJ-11 is just the tip of the iceberg.
03:30The Chinese have funded dozens of varieties of drones and UAVs, using their many state-owned
03:36corporations that also build their space and missile technology.
03:41Moreover, the plan is already building up its capability across the whole spectrum of
03:47its military assets, and they are deploying those capabilities on land and at sea.
03:52For example, China's second carrier, the Shandong, was spotted on June this year with a small
03:58fleet of commercial or commercial derivative drones on its flight deck.
04:05And these images really highlight how the People's Liberation Army is increasing its
04:10effort to develop various unmanned aircraft, including those that can operate together
04:16in networked swarms.
04:18If that were not enough, there is now the case of the Zhuhai Yun.
04:22The Zhuhai Yun is a 290-foot oceanic research vessel designed to deploy various underwater
04:30and aerial drones for various purposes.
04:34This ship is also a drone itself, and it can either be remotely controlled by a pilot or
04:39can be left to navigate the high seas autonomously.
04:44In the words of the manufacturer, it is the world's first intelligent mothership.
04:50And though Beijing officially described that mothership as a maritime research tool, press
04:57news acknowledged that the vessel hosts some military capabilities that can intercept,
05:03besiege and expel invasive targets, whatever this means.
05:09What matters is that there is nothing like this in American or Western availability.
05:20All this effort is becoming to affect the never-ending game played by modern military
05:42forces.
05:43Beyond the 2019 case that we have already described, that anyway is not officially attributed
05:48to the Chinese, there have been plenty of other examples.
05:53In August 2021, the Japanese Self-Defense Force led several fighter shorties intercept
06:01PLA's drones caught flying south of Okinawa.
06:06The drones were of the class of the American Predators or Reapers, and they were believed
06:11to be collecting intelligence in the waters of the Miyako Strait.
06:16It is a critical point of entry to the Pacific, and it has been the theater of increasing
06:21Chinese activity.
06:23These adversary drones are meant to stimulate America's most capable air defenses and those
06:30of the Allies as well, to collect electronic intelligence of an extremely high quality.
06:37By gathering this intelligence, then countermeasures can be developed, tactics can be developed
06:43to disrupt or just defy them.
06:46Moreover, capabilities can be estimated and eventually cloned, and tactics can be recorded
06:53and exploited.
06:54Drones like those of 2019 or 2021 are sucking up or helping another nearby platform to suck
07:00up a lot of sensitive information about potential opponents.
07:06These drones were baiting US or Japanese assets, gathering intelligence about their response
07:12or lack thereof, for future actions that, well, we all hope are never going to happen.
07:18And by the way, a ship's or an aircraft's electronic signature is one of the critical
07:24pieces of information that are required to successfully engage the asset.
07:30It is so because it can guarantee a certain identification before opening fire.
07:36This fixes the IFF problem, which is the main problem of modern, long-range, distributed,
07:43network-centric, multi-domain warfare.
08:06I think that nothing epitomizes the Chinese effort like this picture.
08:26This is what is believed to be a satellite image that appeared on the Chinese internet
08:31in December 2019.
08:33This is the Malans Airbase Apron, the Chinese center for developing UAVs.
08:39As you can see, there is everything there.
08:42There are large, long-range, high-altitude vehicles.
08:47There are medium-sized drones that are relevant in a tactical or operational context.
08:52There are small drones that are supposed to operate in swarms.
08:56There are unmanned helicopters, and there are UCAVs, and so on, and so on, and so on.
09:01And this is just a part of the development going on in China.
09:05We will not go through all of them in detail, today this was just an overview video.
09:10This is just the beginning of a series that probably will keep us occupied on and off
09:15for a very long time.
09:17The point that I wanted to make is that it is safe, at least for me, to say that the
09:22Chinese are speeding ahead of the West in UAVs and UCAV development.
09:29So this is something that is definitely worth learning about.
09:32Anyway, feel free to draw your own conclusions and let me know in the comments below, they
09:36are open for everyone who has something to say.
09:40When I saw this photo for the first time, well, my reaction was, yeah, I thought it
09:49was just another development in the Chinese drones and UCAV space.
09:54Something that happens way too fast and way too often.
09:58You just get desensitized after a while.
10:00The Chinese described it as a high-performance unmanned surveillance aircraft.
10:07Yes, interesting, but that's not something that we haven't seen already, so yeah, let's
10:13move on.
10:14However, something wasn't right.
10:16I had the sensation that I was missing something important to understand the Chinese strategy.
10:23And then, one day, I suddenly realized.
10:26I realized that if I was right, they just found a way to put everyone else in big trouble.
10:39The WZ-8 was presented during a parade in 2019 and it made waves.
10:46In fact, it wasn't a mock-up, it was the real thing.
10:51The two units being shown were undoubtedly real vehicles.
10:54So it is an unmanned, pure delta-wing aircraft with a razor-thin leading edge.
11:02That's the most classic of the delta-wings, and delta-wings are one of the marvels of
11:06aerodynamics.
11:07It is very simple and streamlined, and it has quite a beautiful line.
11:22It features two vertical surfaces at the wingtip.
11:27The horizontal control surface is seen quite conventional, with the two moving parts which
11:32are classic for the delta-wing.
11:35And even the construction is nothing special, because it is a conventional metallic riveted
11:40structure.
11:42The propulsion is provided by two small liquid-fuel rocket engines.
11:52They seem like two separate engines, and not just one engine with two nozzles, because
11:57there are two pumps exhaust, or at least that's what they seem to be.
12:02The size is quite small, it's estimated to be 11.5 meters in length, with a wingspan
12:09of 6.7 meters.
12:12Guys, I'm metric, get used to it.
12:14The Chinese presented it as a reconnaissance aircraft.
12:17High supersonic reconnaissance aircrafts are, well, nothing new.
12:22The SR-71 is still present in everyone's memory, and Lockheed Martin is working on the SR-72,
12:30or at least so it seems.
12:33But today it's not sophisticated technology, particularly if you are using rocket engines.
12:40Provided that the vehicle is designed to be intrinsically stable, even guidance is not
12:45really a problem today.
12:47The WZ-8 seems to have what looks like a nice satellite antenna opening on top of the fuselage,
12:55and in the worst case, pre-programmed flight paths have been flown since the 50s.
13:01The two vehicles shown at the parade don't show any specific payload, but it is easy
13:05to imagine that installing for example a radar is not terribly difficult.
13:11It will still require some clever power generation source, but still nothing too much out of
13:17the ordinary.
13:18So I sort of forgot that vehicle.
13:20But then, in December 2021, I read an article that sort of left me perplexed.
13:27In an analysis that appeared on Military Watch, the aircraft was reported to be capable of
13:32loitering and also to be hypersonic, reaching a top speed of Mach 7.
13:38Which is low hypersonic, but definitely hypersonic.
13:41And that I thought it was weird.
13:43In the article no source was mentioned for this data, so I imagine it was some intelligence
13:49officer.
13:50Well, if this is the case, I am completely wrong and what follows is irrelevant.
13:54Loitering and hypersonic, or in general high Mach number, don't go well together.
13:59The SR-71 cruising at Mach 3.2 had a turning radius of hundreds of kilometers.
14:07But I think there is another and more compelling reason to doubt the hypersonic claim.
14:11I looked for a picture of the aircraft from the top and then I measured the angle between
14:16the two leading edges.
14:18Then I halved the angle because the aircraft is obviously symmetric.
14:22The corresponding Mach number that I found was 2.85, which is fast, but not hypersonic.
14:29I assumed that the aircraft was flying at 25,000 meters, about the same as the SR-71.
14:36At that height, in standard atmosphere, the speed of sound is 299 meters per second, in
14:45old money 1,660 knots, which is very fast but not hypersonic and slower than some western
14:53air-to-air or surface-to-air missiles.
14:56The WZ-8 would be a very difficult target, but not 100% impossible.
15:02Why I say so?
15:03Well, in front of everybody traveling at supersonic speed there is a cone, which is called the
15:09Mach cone, formed by a conical shock wave.
15:13The shock wave is just a surface where the airflow slows abruptly, releasing quite a
15:20lot of heat.
15:21The inclination of the shock wave is the Mach angle.
15:25We discussed all of this in the hypersonic series, so, as usual, links above and below.
15:31As the aircraft progressively accelerates, the Mach cone gets narrower, the angle decreases.
15:39At some point, the shock waves will touch the aircraft's leading edge, and for the WZ-8
15:47this should happen around Mach 2.85.
15:50Now, what happens if the aircraft accelerates?
15:53Well, the parts that now fall outside of the main shock wave will start generating their
15:59own shocks, but what's most important is that the main shock wave is going to interfere
16:04with the wings.
16:05But also the control surfaces are blanketed by the shock waves and this could potentially
16:10create some nasty consequences.
16:13So it's not an ideal condition and you would rather avoid, but in the past there have been
16:18several designs that flew exactly in these conditions, for example the B-58 was one of
16:25those.
16:26So, with an adequate aerodynamic design, there is no reason why the aircraft couldn't fly
16:30faster, save for a problem.
16:33At nearly hypersonic speed, shocks interfering with the aircraft's structure tend to do stuff
16:40like this.
16:41These are pictures of the famous experimental aircraft X-15 and these are the effects of
16:48secondary shocks interfering with the structure.
16:52The heat released by the flow going through the shock transition is such that it can easily
16:58devastate a structure which is not adequately shielded with materials like steel or titanium.
17:05And even with those it's, well, complicated.
17:09And by the way, the top speed reached by the X-15 was Mach 6.74, which is exactly in the
17:16bracket that has been reported for the WZ-8.
17:21From the pictures the aircraft doesn't seem to have any protections, save a small shiny
17:27metallic nose.
17:28It could be faster than Mach 2.85 and probably is, but I would really be surprised if it
17:36was faster than Mach 3.5, give or take.
17:42But there is another detail that doesn't seem aligned with the hypersonic speeds.
17:47Look at the vertical surfaces, they seem to have a pretty ordinary aerodynamic profile.
17:53In hypersonic missiles or aircraft those surfaces tend to be triangular, in section
18:00or sort of very elongated lozenges.
18:03The reason is, well, complicated and it is explained in some details in the hypersonic
18:09series.
18:10In any case, these vertical surfaces don't seem adequate to hypersonic flight.
18:15Maybe the hypersonic speed has been really observed and there are factors at play that
18:19I don't know.
18:21But if it's not the case, then I really don't understand what an airplane like this is for.
18:28The common interpretation goes like this, since reconnaissance satellites are quite
18:32vulnerable and there are a few countries that actually have either hard or soft kill capabilities
18:38against them, then a high-speed rocket-powered drone could execute some sprints above an
18:45area that you want to attack, acquire the information and then glide back to the base.
18:52And obviously reconnaissance is the fundamental part of every kill chain.
18:57And for China we can imagine that it is extremely important for them to build a kill chain for
19:03their anti-ship ballistic missiles.
19:06But now you can see a problem coming.
19:09Rocket engines have a very short burn time.
19:12They have high specific impulse, they can push you very fast, but their thrust won't
19:17last long.
19:18If we accept that the aircraft can effectively fly at Mach 2.85 and we hypothesize a burn
19:25time of 10 minutes, which is very generous, the numbers that we get are not very encouraging.
19:32The aircraft is air-launched by an H-6 bomber, and the bomber will likely won't be capable
19:38to go too far out at sea if the airspace is somewhat contested.
19:44Then once released, the WZ-8 is probably capable of flying a stint of about 500 km at Mach
19:522.85, ignoring the acceleration time, for sake of simplicity.
19:57This means for example that it could go across Taiwan and come back.
20:02This means that it could start from nearby Hainan, fly above the South China Sea and
20:10land in one of those artificial islands that China has built in the area, or nothing else.
20:17It could reach the southern part of Japan, but in that case the aircraft would likely
20:21be lost, cause the gliding range is not enough to come back.
20:26And just for the numbers, a delta wing like that should have a glide ratio around 8 to
20:3010, and flying at 25,000 meters, this means a gliding range of about 250 km, at best.
20:40True, at that speed and that altitude it is definitely not an easy target, and the horizon
20:45is a whopping 560 km, but that would be hardly usable if the payload was some sort of optical
20:54device or even a radar.
20:56In fact, there is just not enough space for any really powerful optical reconnaissance
21:03device or even for a powerful radar.
21:07For a radar?
21:08Yes.
21:09For some cameras?
21:10Yes.
21:11Powerful ones?
21:12Well, probably no.
21:13And in an aircraft with rocket motors, there's always the problem of power generation.
21:17However, it could make more sense if it was equipped with some passive electronic surveillance
21:24systems.
21:25That would require way less power, and the range would depend probably more from the
21:31emissions being received.
21:33Moreover, if this is expected to replace satellites in all those cases where the satellites have
21:40been disabled, we should also expect that also the communications satellites are not
21:46going to be available, so the antenna visible at the top of the fuselage won't work.
21:51The only way of recovering the information was landing the aircraft back to the base,
21:56but then in that case you can't do any mission where the aircraft is lost, so no long range
22:03missions.
22:04If I am right, the WZ-8 is not really a useful platform to identify carrier group in the
22:12middle of the Pacific and pass the targeting to the anti-ship ballistic missiles.
22:17If my calculations are correct, we are left with just one possibility.
22:20The aircraft that we have seen are still experimental, and honestly, if you consider
22:25that they don't have any visible payload, well, this is probably not impossible.
22:32Probably the Chinese calling it a reconnaissance aircraft, they have just embellished the picture.
22:38A rocket propelled drone like this should be probably bigger to increase the engine
22:44burn time, it should show some sign of a payload, and it also shouldn't be that difficult
22:52to introduce some stealth features to reduce the RCS, so it is well possible that the Chinese
22:58are developing a rocket propelled reconnaissance drone, but if I am right, it seems that they
23:04are not there yet.
23:05And that was it, I had fun with the calculations, I felt very satisfied, and all was well.
23:13But something kept going round in circles on the back of my head.
23:18When I made the video about the Chinese drones, I was reminded obviously of the aircraft,
23:23but I didn't give it much consideration.
23:26Then by pure chance, I watched a video on YouTube.
23:35And then I understood what the Chinese are doing with this drone.
23:40The WZ-8 is a decoy.
23:43It is an aeroballistic system designed to fly in the high atmosphere, nearly in space,
23:50but in a suborbital trajectory.
23:52And it is not stealth, and it is conspicuous on radars, so that it can't be ignored by
23:58a battle group.
24:00Consider this scenario.
24:01Take a group of WZ-8 and launch them in the generic direction of a carrier group or any
24:08other battle group.
24:09They will come at a very high altitude, and in this case, since the atmosphere will be
24:14thin, they will be hypersonic.
24:17They will show up prominently in radars or infrared sensors, and probably the battle
24:22group will be forced to turn on the sensors to try to identify the threat.
24:28And then, with a payload of passive sensors, they could geolocate the group and relay their
24:34position back, not to satellites, but toward the ballistic missiles flying behind and above
24:41them.
24:42I know, it's a complicated scheme of operations, but time on target wasn't really invented
24:46yesterday.
24:47The aircraft features an undercarriage because in training you don't want to throw away a
24:51drone every time, plus in this way it can also act as a reconnaissance asset where the
24:57range is appropriate.
24:59And speaking of range, if it is not flying atmospheric, but is flying a suborbital trajectory,
25:05then the range would be much more than 500km, maybe 2-3 times even more potentially.
25:13And that would probably be enough to reach quite deep into the Pacific.
25:17Well, maybe you don't even have to throw all of them away, because maybe some of them could
25:23land on the Salomon Islands.
25:25This theory, though, has a weak point, and that's the reason why many analysts think
25:31that the aircraft is for atmospheric flight.
25:35There seems to be no way of controlling the aircraft outside of the atmosphere, there
25:39are no maneuver thrusters, and the nozzles are not gimballed.
25:44Wow, what about reaction wheels?
25:47The Chinese know this technology very well, it's totally mainstream technology for satellites.
25:53At the end of the day, the aircraft doesn't need a lot of authority, the one thing that
25:58it needs to do is just keeping the orientation in space, it doesn't really need to maneuver.
26:04As long as the attitude while entering the lower atmosphere is correct so that the aerodynamic
26:10control surfaces can pick up the job, then that's all is needed.
26:15And there you have it, this is my interpretation.
26:18Maybe this video is completely wrong, it's just a pile of rubbish, but what do you think?
26:24Well, let me know in the comments below, they are open to everyone.
26:32When I was researching my first video about the Chinese drones, I saw this picture, and
26:37I thought, what the...
26:39Yes, this drone.
26:41This drone attracted my attention, and Otis too.
26:44Otis, what do you think it is?
26:47It is a high altitude long endurance drone, sir.
26:50Yes, of course, look at that wing, but what is it for?
26:54It is for electronic intelligence?
26:58No, sir.
27:00So you do know what is that thing?
27:03Yes, sir, it was in the press.
27:06OK.
27:11The first rumors about Project 973 Divine Eagle by Shenyang Aircraft Corporation emerged
27:21in 2012 in a book about Chinese aeronautical history.
27:26In May 2015, some pictures and some engineering diagrams were leaked on the Chinese internet.
27:33The configuration shown at the time was not the final one, but it made waves, because,
27:41well, it was big, and it was very unusual.
27:46It didn't take long before some clear pictures emerged from behind the Great Chinese Firewall.
27:53First in July 2015, and then in August, leaked pictures were showing the drone
27:59parked on the apron and taxing.
28:02And it was a shock.
28:04Nobody had ever seen anything like that.
28:08First, it was enormous.
28:10We don't have the exact size, but estimates from the pictures indicate a length between
28:1714.5 and 18 meters and a wingspan between 40 and 50 meters.
28:25The American Global Hawk, as a comparison, has a wingspan of about 39.9 meters.
28:34Unlike the Global Hawk, though, this one doesn't have a fuselage.
28:38It has two fuselages.
28:41In fact, the aircraft has two almost identical fuselages.
28:46On the back, they are joined by the central section of the wing.
28:50On the nose, they are joined by an additional aerodynamic surface that I believe is acting
28:55like a classic canard.
29:18It is not clear why this solution was chosen.
29:21Surely the box formed by the two fuselages and the two aerodynamic surfaces is pretty
29:28stiff without requiring too much structural weight.
29:32It is a unique solution and I suspect that the reason it was chosen was not aerodynamic
29:39nor structural.
29:41However, 10 out of 10 for creativity.
29:51Sir, we have to complete the video, sir.
30:00The engine is like a turbofan and it is mounted above the wing between the fuselages.
30:07The wing itself has no sweep, but it has a very high aspect ratio, which is typical of
30:14high efficiency subsonic wings.
30:17The already mentioned Global Hawk has a similar wing.
30:20The U-2 uses the same configuration.
30:35Sir, sir, please do not react like this, sir.
30:39The prominent tail feature are the two vertical stabilizers.
30:45They appear to be quite large if they are compared with the overall size of the aircraft
30:51and probably the reason is the very short arm.
30:54But this was probably a compromise because they have chosen this very particular general
31:00configuration.
31:01So we still have a question to answer.
31:03Why did they choose this configuration?
31:15When the material leaked in 2015, there were pictures of aerodynamic simulations calculated
31:25at 25,000 meters of altitude and Mach 0.8.
31:30This actually makes the aircraft mission quite clear.
31:33Intelligence.
31:40The aircraft is painted in green and grey and this means that either there are two different
31:44materials or the Chinese are just fooling us in believing so.
31:50Since the former is much more likely, well, it actually seems that the aircraft is covered
31:57in big radomes.
31:59Well, they're not really domes, but yeah, you get it.
32:02The original leak was showing up to seven radar either in X-band or UHF, though the
32:09most recent pictures don't seem to show as many.
32:12This is telling us that the aircraft is probably an AWACS.
32:18An Unmanned High Altitude Very Long Endurance AWACS.
32:24It could have a satellite dish under the left dome for communications and two radars under
32:30the grey areas, probably one for each side.
32:33If other leaks are to be believed, it is possible that under those grey areas there is a modified
32:41version of the Chinese JY-26 radar.
32:45The JY-26 is a rather peculiar radar.
32:48It is a ground-based AESA radar working in UHF band.
32:54These radars operate at low frequency, long wavelengths and they can indeed see stealth
33:02aircraft.
33:03But since there is no free lunch, the quality of the radar track is quite similar.
33:10While the distance measured could be quite precise in the order of a few hundred meters,
33:16the angular precision is low, and this means that the detected position at long range could
33:24literally be off by tenths of kilometers.
33:28But this accuracy can be greatly improved by combining different sensors, and this is
33:37probably the mission of the Divine Eagle.
33:39In fact, a fleet of these aircraft could complement the ground-based radars and the
33:45more conventional AWACS, making an airspace very hard to be penetrated even by very low
33:51observability aircraft.
33:53According to some observers, the Divine Eagle entered in limited operational service in
33:582018 and since then it has been observed in several airbases around China.
34:04Unfortunately, we don't know how many are in service, we don't know anything about the
34:08production plans, we don't know anything about upgrades, basically we don't know anything.
34:15Yes, the Divine Eagle is a well-preserved secret.
34:19Sir, we didn't explain the configuration.
34:22Low-frequency radars are large, the frequency at which they operate forces geometric constraints
34:30on the antennas.
34:32But to carry a big antenna there are more conventional solutions, it could have been
34:36like this or like this.
34:43In the former case, the canoe on top of the fuselage has an adverse effect on the aircraft's
34:49longitudinal stability.
34:51Of course, it can be corrected, and it works pretty well, but it is a further complication.
34:58In the latter option, the position of the wing actually limits the size of the antennas
35:03and anyway placing them side by side along the fuselage could create interference and
35:09cooling problems.
35:10So what I believe the Chinese designers did was to create an unimpeded fuselage side where
35:18to host the big radar antenna.
35:21And then they split the fuselage in two to have less interference and better thermal
35:28management.
35:29Of course, if you are transforming an already existing civilian aircraft or a transport
35:35aircraft, all these issues can be solved, they have been many times.
35:40But in this case, they were starting from scratch, so why bother?
35:44Ah, and now it is obvious why the aircraft doesn't have any stealth feature.
35:49I don't need to explain this, right?
35:51Please let me know in the comments below.
35:54The first time I saw the WZ-7 Shoredragon, I thought, here we go again, the Chinese delivered
36:03another world first.
36:06And the key question was, why?
36:09Why do they need this complexity?
36:12Isn't the reason apparent, sir?
36:14No, Otis, this time is not obvious at all.
36:24The first news of these drones appears in 2006, when a mock-up was on display at Zhuhai
36:32Airshow.
36:32The story of the development, though, is not entirely clear.
36:36For example, we know that in 2011 it was seen undergoing electromagnetic compatibility
36:44tests, but we don't know when the first flight was.
36:48We know that serial production started in 2016, and the first units have been deployed
36:54in 2021.
36:56However, the aircraft has been seen operating even at an earlier date.
37:01The WZ-7 has been seen shadowing American ships in the Taiwan Strait, also controlling
37:09Korea flying from airfields in the Chinese Liaoning province.
37:14More recently, it has been spot entering the Taiwanese air identification zone.
37:20All of this because, well, obviously, the Shoredragon is an intelligence platform.
37:25Ok Otis, what numbers do we have about this drone?
37:30As usual, we do not have official figures for Chinese drones, but we rely on partial
37:35information collected mainly at airshows or estimates from western analysts.
37:40The aircraft has a take-off weight of 7,500 kg, a payload is 650 kg, and a maximum speed
37:48is 750 km per hour.
37:51The range is estimated to be 7,000 km, the endurance is 10 hours.
37:57The engine is a Gizhou WP-13 turbojet with 43.1 kN thrust.
38:03Well done, thank you Otis.
38:05The aircraft's general configuration is typical of high altitude, long endurance,
38:11unmanned aerial decals, long and thin wings, a dorsal air intake, a relatively clean and
38:20streamlined shape, V-tail, and some minimal stealth features.
38:25These are all typical features of an aircraft that is built for range and endurance rather
38:31than speed or maneuverability.
38:33Navigation sensors seem to be hosted in this canoe-shaped structure at the front of the
38:39aircraft.
38:40This ponson is the right size and shape for a side-looking airborne radar, probably an
38:48AESA one.
38:49From the position we may suppose that it is designed to look down, so this aircraft is
38:54likely a radar reconnaissance platform and an electronic intelligence system.
38:59This dome on the back could host an optical sensor, but it is most likely another antenna
39:05housing.
39:05I couldn't find a clear picture, so I'm not sure.
39:09So far so good, but I think that many among you will be on the edge of the seat about
39:16a unique feature of the Sword Dragon.
39:20And I can understand that because the obvious elephant in the room!
39:23Sorry, I keep forgetting every time I mention...
39:32Sir, we have a big problem, sir.
39:34How big?
39:35As big as elephant-sized ejections, sir.
39:39Excuse me, excuse me.
39:45So...
39:49Uh...
39:50Bear with me, okay?
39:52Bear with me a minute, just a minute, bear with me.
39:55Okay, we are back and now we can finally address the mystery of the very peculiar wing of the
40:01WZ-7.
40:03In the sources it was sometimes called a phi wing, like the greek letter.
40:09I don't have any specific name for this configuration, so I believe we can adopt it.
40:14So it seems to be a tandem wing with a big swept back wing in front and a smaller
40:22swept forward wing behind.
40:25The first question is...
40:27Is the aft surface lifting upwards, like a wing, or downwards, like a tail?
40:36So from the pictures it is impossible to say.
40:39None of the pictures that I could find is close enough to appreciate any detail of the
40:45aerofoil.
40:46It sort of seems to be symmetric but laminar, but this seems unlikely because a symmetric
40:53aerofoil is probably not going to be very efficient.
40:56Also none of the pictures is close enough or from the right angle to assess the difference
41:02of the angles of incidence between the two surfaces.
41:07A negative angle of attack would be a giveaway of the aft surface acting like a tail and
41:14vice versa.
41:15However, we need to consider that the aft surface is affected by the front wing downwash,
41:21so its effective angle of attack is reduced.
41:26So in the end the tail could be lifting downward without being twisted too much.
41:31However, I believe that the aft surface is lifting.
41:36In fact, if we consider the position of the undercarriage, from that we can estimate the
41:43rearmost position of the center of gravity.
41:47And the center of gravity seems to be closer to the front wing but between the two surfaces.
41:55This would mean that the aft surface would be lifting but also that the aircraft is
42:02intrinsically unstable and this would require fly-by-wire and a flight control system.
42:09Why would you do that on an aircraft that doesn't need to be really maneuverable or
42:15doesn't have a massive shift of the center of gravity?
42:19Well, it beats me.
42:21It is more weight, more complexity, more development time.
42:26For what?
42:27Sorry, sorry, sorry for the interruption.
42:29This is the editing us a few days later.
42:33I did this analysis again and now I have the impression that probably the center of gravity
42:40is slightly ahead of the aerodynamic center.
42:44And in this case the aircraft would be stable.
42:47This would mean that if the aft wing is lifting then the only downward lift is from the V-tail
42:57but it seems too small.
43:00So I would expect that the aft wing would be lifting down.
43:05So at this point I don't really know what to think.
43:09On with the show.
43:10So I can't really work out the rationale for such a configuration from an aerodynamic point of view.
43:17I'm sure that the designers at Chengdu will have compelling reasons but I can find them.
43:24It is also worth noting that in the most recent photos these nacelles at the junction of the two
43:30surfaces have been introduced in place of vertical surfaces.
43:37I believe that these have been introduced because those vertical surfaces were creating
43:43at the intersection with the wings a small system of vortices that was probably not giving
43:49any real lift benefit but was just introducing extra drag.
43:54It is also worth noting that the aircraft has swept wings,
43:58not dissimilar from what you can find on a civilian airliner,
44:02so I do expect that the cruise speed is actually a bit above the declared 750 km per hour.
44:09With a wing like that we may expect it to be around Mach 0.8,
44:13that is about 850 km per hour, which is pretty fast for a HALE aircraft.
44:19STRUCTURAL REASONS
44:29Okay, if we can't find a rationale for aerodynamic reasons,
44:34maybe there is one for structural reasons.
44:38So in flight the wing is bent upwards and the bending moment increases from root to tip in this way.
44:46And obviously the wing must be designed to withstand the bending.
44:50Upper surface must resist compression, the lower surface must resist traction.
44:56The junction of the two wings is probably reducing bending moment on the main wing.
45:03And by the way such an arrangement is pretty common,
45:06it happens every time you have a wing mounted engine.
45:10The aft wing will bear its own loads, but it also seems to be compressed by the main wing.
45:17Such a thin structure being compressed, well it's not ideal, it's probably prone to instabilities.
45:24And considering that on the horizontal plane the two wings obviously have an angle,
45:29I mean there's also a torsion, that yeah it's complex and definitely not ideal load situation.
45:39I can see this configuration as a measure for reducing some structural weight,
45:45but I'm not entirely sure if this can really be achieved and it is definitely
45:52quite a complicated arrangement.
45:54However the bending of such long wings has never really been a problem,
45:58there have been several solutions and it's not particularly difficult to design.
46:05Every sport glider has a wing like that.
46:08So it's quite difficult to understand why they went to such a length
46:12just to make a slightly stiffer and maybe slightly lighter structure.
46:19The only real advantage that I can see is that a forward swept wing with the tip captive,
46:26like in this case, definitely won't have torsion problems.
46:31But even in this case we have known for decades how to do that using composite materials.
46:39So again it's not clear why the Chinese designers went into this complication,
46:45even from a structural point of view.
46:48So I really can't find any compelling advantage in this configuration,
46:53maybe it's just me not seeing it.
46:55If anyone has a better idea please let me know in the comments below.
47:00If any of the designers is watching this and wants to contact me to explain what happened here,
47:05they are welcome.
47:07We will go over again this aircraft and we'll see their ideas.
47:10Obviously if it's not classified information.
47:13So I suppose that sometimes you should just accept that we are not understanding.
47:18Well at least not entirely.
47:20However this is not the first case that we are covering a very peculiar Chinese drone.
47:27And the relative video is going to appear beside me.
47:30So if you want to learn more about Chinese drone, Chinese aeronautics and so on, click on them.
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