Chinese UAV/UCAV development

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Deino

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I thought the Cloud Shadow was exclusively an export-oriented version of the Sky Wing III / Wind Shadow.

Yes, but this does not exclude a variant for the naval aviation too if they would prefer a single engine design?
 

taxiya

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Yes, but this does not exclude a variant for the naval aviation too if they would prefer a single engine design?
What I read on FYJS is that the two are the same aircraft. PLA adopts the twin-turbofan (500kgf thrust each) while the export version on the show is equipped with one turbojet of 1000kgf thrust. What would be the advantage of adopting the single engine version by PLAN? The total thrust is the same meaning no take-off advantage, the turbojet version has higher fuel consumption that shortens range, but the two turbofans may take up more room (less fuel). Don't really know how to choose.
 

plawolf

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What I read on FYJS is that the two are the same aircraft. PLA adopts the twin-turbofan (500kgf thrust each) while the export version on the show is equipped with one turbojet of 1000kgf thrust. What would be the advantage of adopting the single engine version by PLAN? The total thrust is the same meaning no take-off advantage, the turbojet version has higher fuel consumption that shortens range, but the two turbofans may take up more room (less fuel). Don't really know how to choose.

Turbojets are old tech with worse fuel consumption, but should be pretty price competitive to buy and maintain compared to turbofans.

However the maths gets less straight foward with 1 high thurst turbojet vs 2 lower thurst turbofans.

For naval aviation, typically twin engined designes are preferred as that gives extra redundancy as in many climates, bailing out far from friendly ships is effectively a death sentence for the pilot, with rescue unlikely to reach the pilot before hypothermia claims them.

However, that is less of a concern for unmanned drones.

The PLA would prefer twin engines as getting a drone back on one engine is infinitely preferable to picking up its pieces from an impact crater.

However, would a naval carrier skipper even want to risk trying to recover a damaged drone running on one engine? It is unlikely to have sufficient thrust to make it back into the air for another pass with only one engine if it missed the wires on the first attempt. With lots of personnel and far more expensive aircraft also on deck, is that shot even worth taking when you run the risk of that drone crashing into packed aircraft and deck crew if things goes sideways?
 

Totoro

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Two small turbofans should have a significantly smaller IR signature than one bigger turbojet. Especially when exhaust is buried inside like it is on the PLA variant.

While radar can track the uav, it also means radar itself can be tracked. Suppressed ir signature means a bunch of short range anti air systems are deprived of good tracking data.
 

taxiya

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Or simply because the 1000kgf class turbofan was not ready yet when Sky Wing III was concepted.
  • 500kgf turbofan program stared in 2003, first full engine was assembled within 16 months (2004) 11 years before Sky Wing III showed up in 2015. Now it is 14 years. It must have been mature for many years.
  • 1000kgf turbofan reached 100% design thrust in January 2016. It is less than 3 years. It may not be mature yet or just becoming. Maybe later batch of Sky Wing (IV) can be re-engined with this new engine.
 

Stratton

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Turbojets are old tech with worse fuel consumption, but should be pretty price competitive to buy and maintain compared to turbofans.

However the maths gets less straight foward with 1 high thurst turbojet vs 2 lower thurst turbofans.

For naval aviation, typically twin engined designes are preferred as that gives extra redundancy as in many climates, bailing out far from friendly ships is effectively a death sentence for the pilot, with rescue unlikely to reach the pilot before hypothermia claims them.

However, that is less of a concern for unmanned drones.

The PLA would prefer twin engines as getting a drone back on one engine is infinitely preferable to picking up its pieces from an impact crater.

However, would a naval carrier skipper even want to risk trying to recover a damaged drone running on one engine? It is unlikely to have sufficient thrust to make it back into the air for another pass with only one engine if it missed the wires on the first attempt. With lots of personnel and far more expensive aircraft also on deck, is that shot even worth taking when you run the risk of that drone crashing into packed aircraft and deck crew if things goes sideways?
And so we get to one of the benefits of RPAs: attrition tolerant.
 

gelgoog

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Once the Ivchenko-Progress AI-222 engine is in production in China for the L-15 trainer they should have a 2520 kgf engine with dry thrust or 4200 kgf thrust with reheat. It is a turbofan engine, of more modern construction, so it should have lower fuel consumption. That could be used for a more powerful drone that needs to carry a weapons payload.
 

Hendrik_2000

Lieutenant General
New kerosene burning engine CH4 that will increase the height ceiling and extend the operating time via JSCH
As well open the possibility of operating from the ships

Popular Chinese drone CH-4 to upgrade engine
By Liu Xuanzun Source:Global Times Published: 2018/12/18 14:34:30

Use of kerosene allows it to fly higher, be plateau combat ready

a004602d-4e76-498e-9512-f4d16a08b2bf.jpg

A CH-4 unmanned aerial vehicle (UAV), characterized by its long battery life of 40 hours, is displayed at the 10th China International Aviation & Aerospace Exhibition in Zhuhai, south China's Guangdong Province, Nov. 12, 2014. The 10th China International Aviation & Aerospace Exhibition, which takes place in Zhuhai from Nov. 11 to 16, features various UAV drones for both military and civilian use.(Xinhua/Liang Xu)

The Chinese CH-4, one of the best-selling armed reconnaissance drones on the international market, will be fitted with a new and stronger engine that would allow it to fly higher than the world's highest peak.

The CH-4 will soon see its old piston engine that burns gasoline replaced with a domestically made next-generation heavy-fuel engine that burns kerosene, a spokesperson of the Chinese Academy of Aerospace and Aerodynamics (CAAA) under the China Aerospace Science and Technology Corp (CASC), the drone's manufacturer, told the Global Times on Tuesday.

The exact date for the upgrade and the new designation for the new version will be announced at a later date, the CAAA spokesperson said.

The heavy-fuel engine will allow the drone to reach a height of 9,000 meters, according to a Monday report on the WeChat public account of Ordnance Industry Science Technology, a Xi'an-based periodical on national defense industries and technologies. That is even higher than Mount Qomolangma, known in the West as Mount Everest, which is 8,844 meters high.

With the old piston engine, the CH-4 can only reach 7,200 meters high, the report said.

Being able to fly higher means the drone is less likely to be detected and hit by a surface-to-air missile and more capable of combat in plateau regions, military experts said.

Fu Qianshao, a Chinese air defense expert, told the Global Times on Tuesday that by switching from gasoline to kerosene, the new engine will open the door for the CH-4 to operate on large vessels.

Gasoline is volatile and may lead to fire accidents, which is especially dangerous at sea, which explains why gasoline is not allowed on military vessels, Fu said. Heavy-fuel like aviation kerosene is much safer, he said.


The new engine can also reduce the fuel consumption by 20 percent compared to the old one, and significantly shorten the takeoff ground run distance, Ordnance Industry Science Technology reported.

Heavy-fuel is also less expensive than gasoline, Fu noted.

The CH-4's upgrade is similar to the US-made MQ-1 Predator drone. Its updated version, MQ-1C Gray Eagle, uses a heavy-fuel engine, the report said.

With CAAA's new armed reconnaissance drone on the market, the new domestic engine will help the CH-4 in terms of combat capability as the drone will also see a further price reduction following mass production, the report said.

The CH-4 has become one of the best-selling drones on the international market, the report said.

Many countries, including Algeria, Iraq, Egypt, Saudi Arabia and the UAE are operating the CH-4, Jane's Defence Weekly reported.

At Airshow China 2018 in Zhuhai, South China's Guangdong Province in November, the CAAA revealed the latest additions to the CH drone series: the flying-wing stealth combat drone CH-7 and the tilt-rotor drone CH-10.
 
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