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Singapore-based aviation contractor aims to build supersonic combat drone in Seletar hangar

Singapore-based aviation contractor aims to build supersonic combat drone in Seletar hangar

Kelley Aerospace says the Arrow, seen in this artist's impression, can fly at speeds of up to Mach 2.1, or 2,572km/h. (Photo: Kelley Aerospace)

SINGAPORE: A dozen drones carrying bombs are flying so fast, faster than the speed of sound, that they are leading a fighter jet into battle.

Some of them fall away to take out high-value targets, hitting at such speed that the enemy has no time to react. Others become bait for hostile missiles, sacrificing themselves to protect the jet bursting in from behind to destroy the remaining threats.

This is how a supersonic unmanned combat aerial vehicle (UCAV) could be used during aerial warfare, and one of these machines could be built in Singapore.

Kelley Aerospace chairman Avraham Kelley posing with a full-sized model of the Arrow at his hangar in Seletar. (Photo: Marcus Mark Ramos)

On Feb 25, Singapore-based Kelley Aerospace unveiled the Arrow, a combat drone concept made of carbon fibre that it said will fly at speeds of up to Mach 2.1, or 2,572km/h.

It is 14m long, 9m wide and looks like an alien spacecraft, with its sleek silhouette and dark finish. The company aims to start production in Singapore by August, if it can get enough workers to sustain the manufacturing process.

The Arrow, marketed as an air superiority aircraft, can be used in air-to-air or air-to-ground combat, surveillance operations as well as search-and-rescue missions, company chairman Avraham Kelley told CNA in a recent interview.

“You name it, it’s possible,” he said from his hangar at the Seletar Aerospace Park. “It is left to the creativity of the customer.”

An illustration of how multiple Arrows could fly in sync with a fighter jet. (Photo: Kelley Aerospace)

The Arrow can be launched autonomously and be remotely controlled by two personnel on the ground, the company said in a factsheet. Multiple Arrows, each equipped with different weapons for specific missions, could also be controlled by a manned aircraft.

“These Arrow UCAVs, accompanying the manned aircraft on a mission, can act as baits for lethal surface-to-air missiles, engage enemy fighters, jam enemy communications and radars, and seek and destroy enemy targets or surface-to-air missile sites,” it said.

“The Arrow can be employed in coordinated formations or in swarms that can compensate for any equipment failures to achieve a high probability of success.”

Mr Kelley said the Arrow can carry missiles and external fuel tanks as well as pods for navigation or electronic warfare. It can take off with up to 16,800kg of internal and external equipment including fuel, and can fly more than 4,000km before needing to refuel.

“The payload is dependent on the range you want to achieve,” he said.

Kelley Aerospace said the Arrow will cost between US$9 million to US$16 million (S$12.1 million to S$21.5 million) depending on application and region, a price range that it said was “relatively low”. The company said it has received pre-orders for 100 units.

Mr Kelley says he has been in Singapore since 1986, adding that the local unmanned aerial vehicle industry has "very good" potential. (Marcus Mark Ramos)

Mr Kelley said the programme has attracted “tremendous” interest with “requests from so many different countries”, but declined to elaborate on the customers.

“When we developed this programme, we are doing it for what the customer needs,” he added.

“And because we designed it for something very specific, I think it will come out very soon why this was designed the way it was designed, the timing and everything.”

A 4m-long model of the Arrow. (Photo: Marcus Mark Ramos)

Development on the Arrow began in 2012, with the company conducting a test flight in Israel two years later using a smaller-scale, 4m-long version. Mr Kelley said the results were “better than expected”.

The company plans to do full-scale unmanned tests in four different countries next month, to look at how the Arrow handles high speeds, payload stress and control inputs from the ground.

The aim is to simultaneously launch the Arrow in Israel, Australia, Czech Republic and the US with “one click of a button” in Singapore, and make the drones execute what they are programmed to do.

Kelley Aerospace aims to build its first full-size, functional Arrow at its Seletar hangar. (Photo: Marcus Mark Ramos)

To be able to start production in Singapore by August, Mr Kelley said he needs to fly in about 80 to 100 professionals to train 200 local workers in production techniques. Training will take six to nine months, he added.

The amount of trainers is necessary to ensure workers are taught "very closely due to the multitude of options" involved in building the drone, Mr Kelley said.

"Learning to find the optimal route needs a lot of training and thinking which comes with experience," he said.

"And also, the number of preordered unmanned aerial vehicles are taken into consideration to make up the production line size."

While the Arrow built in Singapore will be a full-scale, fully functioning prototype, Mr Kelley said the company will not be able to ship it abroad due to logistical challenges, like fitting the 14m-long drone in a standard container.

This means that eventually, the drones will have to be built in the country that orders them. “So, you’re creating many dynamics in places that don’t have the capabilities of carbon fibre,” he added.

Kelley Aerospace had also used carbon fibre to build the Black Eagle, another drone it developed in 2008 for civilian operations. The company also provides private jet transportation and retrofits the interior of these jets with carbon fibre.

Kelley Aerospace said an originally made-in-Singapore supersonic UCAV will help raise the country's profile and improve technological innovation in the local manufacturing sector.


This innovation is seen in the construction of the Arrow’s external structure, which is built using moulds and does not contain a single screw, Mr Kelley said.

Four layers of high-grade carbon fibre – with honeycomb material sandwiched in the middle – are first laid out in a mould shaped like the top half of the Arrow’s body. The mould is vacuum bagged, before resin is injected at different points to uniformly shape and harden the shell.

This process is repeated using another mould for the bottom half of the Arrow’s body.

The process of injecting resin into moulded carbon fibre. (Photo: Kelley Aerospace)

Workers will then install internal structures like the engine housing, before “marrying” the two halves together using special adhesive with reinforced carbon fibre.

The company said this technique of using a single mould to create multiple shells allows it to produce one Arrow a day, with Mr Kelley saying it takes 16 people to complete the moulding and marrying process.

“Engine, landing gear and other hardware are all put in after the marrying process,” he added. “Each component has a hatch for installation and removal. There are over 18 hatches in total.”


More importantly, Mr Kelley said this combination of quality materials and innovative construction makes the Arrow light yet strong, enabling it to travel faster than the speed of sound.

As manufacturing techniques improve, carbon fibre composites are increasingly being used in newer aircraft to reduce weight and improve aerodynamic performance. These composites are lighter than similar parts made of aluminium.

The company tested several types of materials that could potentially be used in the construction of the Arrow. (Photo: Marcus Mark Ramos)

Mr Kelley demonstrated the strength of the Arrow’s single-piece outer shell, called a monocoque, by stepping and jumping on a smaller-scale model, pointing out that this action would have damaged conventional drones.

“We have been working in composites for many years,” he said, highlighting that the specific type of carbon fibre used in the Arrow was tested in a lab to ensure it could handle supersonic stresses.

“We tried seven different resins before we chose the right one. There was lot of trial and error in putting together the whole concept, knowing that in the morning when you pick up the aircraft, it’s soft. That’s not what I want.”

Another crucial factor in supersonic travel is the thrust generated by the aircraft’s engines. While Kelley Aerospace said the Arrow’s engines are classified, defence analysts told CNA the drone's potentially supersonic capabilities mean it will likely use jet engines. Conventional UCAVs currently use propeller systems.

Mr Kelley was keen to emphasise the significance of the Arrow's shape. (Marcus Mark Ramos)

Mr Kelley said the Arrow will have thrust vector controls that, coupled with its monocoque shell, will make it “much more manouverable than any aircraft”. The company said the Arrow can endure gravitational loads of up to 16G, depending on its payload.

In contrast, the fifth-generation F-35 stealth fighter jet can handle up to 9G.

READ: F-35: How the fifth-generation fighter jet can take RSAF to the next level

The Arrow’s shape, which comprises delta wings similar to those in the supersonic passenger jet Concorde, also helps it minimise drag and withstand shockwaves when breaking the sound barrier, Mr Kelley said.

“If it had (conventional) wings, it must have a very strong wing support, which adds weight,” he added.


Industry experts said that turning the Arrow's theoretical capabilities into reality will be a challenge.

Mr Chen Chuanren, senior correspondent at aerospace publication AviationWeek, said delta wings are aerodynamically unstable, meaning the Arrow needs to have a “very robust” computer controlling it during flight.

Defense News Asia reporter Mike Yeo said this software needs to respond “much faster” to commands during supersonic flight as compared to subsonic speeds. “So, it’s actually a very big technical hurdle to cross,” he said.

Mr Kelley said his company was forced to develop its own flight computer as “nobody wanted to sell it to us”, adding that it has benefitted from the experience of building its own software for the Black Eagle, the other drone it developed.

The Arrow's flight computer must be quick and robust for the programme to succeed, analysts say. (Photo: Marcus Mark Ramos)

The Arrow’s flight computer can be synced with other manned aircraft like a private jet or an F-16 fighter jet, he said, allowing the drone to be what the industry terms as a “loyal wingman”.

“If you have an F-16 at the back and you have 18 or 20 drones in the front, the fighter jet is very safe,” Mr Kelley said. “And if the missiles hit the drones, they’re unmanned.”

The computer can also control how fuel is dispersed through the drone, balancing its centre of gravity regardless of where it carries its payload.

Moving forward, Mr Chen said the company would need to further develop the Arrow’s autonomous capabilities given its potential uses.

“Definitely, there'll be some sort of artificial intelligence involved as you go further into the manned-unmanned teaming concept,” he said.

“Things like aircraft separation, the profile that they fly, or how they react to enemy encounters.”


Given that the Arrow will be built with high-quality materials and use the latest technology, Mr Kelley acknowledged that production costs are “very expensive”.

But he maintained that the programme is entirely self-funded, with no participation from investors or governments.

He reiterated the affordability of the Arrow’s price tag of up to US$16 million, pointing out that some manufacturers can spend US$2 million developing a drone before selling it for US$18 million.

Kelley Aerospace also retrofits private jet interiors with carbon fibre to make them lighter. (Photo: Kelley Aerospace)

Nevertheless, Mr Kelley said making money is “not an issue”, adding that the profits will come in once the company starts producing at scale.

“I’m looking at this vehicle to not just see war, but also prevent war,” he added. “Because you can imagine, if you have 20 aircraft like that in your base, and knowing the capabilities, people will think twice before they can do something.”

Mr Yeo said a lot of these expensive programmes “tend to be user-driven”, meaning that potential customers would go to contractors about a system with specific capabilities that they want, rather than the other way round where contractors develop a system and look for buyers.

Mr Chen said the development of UCAV programmes such as this one could be accelerated by different “stressors”, including an arms race or tension between different countries.

A US Air Force MQ-9 Reaper drone sits in a hanger at Amari Air Base, Estonia, Jul 1, 2020. (Photo: Reuters/Janis Laizans) FILE PHOTO: A U.S. Air Force MQ-9 Reaper drone sits in a hanger at Amari Air Base, Estonia, July 1, 2020. U.S. unmanned aircraft are deployed in Estonia to support NATO's intelligence gathering missions in the Baltics. REUTERS/Janis Laizans

The US already operates several UCAVs and has used them in actual combat, while China has developed a high-speed reconnaissance drone powered by rocket engines.

Military news website The War Zone reported in 2019 that China’s WZ-8 drone, which the country showcased during its grand 70th-anniversary parade, can fly at high altitudes and reach a top speed of between Mach 3.5 and Mach 4.5.

The Telegraph also reported on Mar 2 that Turkish defence firm Baykar is developing a supersonic drone that is currently in the concept stage.

But Mr Kelley is confident that the Arrow will be the world’s first supersonic UCAV.

“I can tell you one thing: If there was a supersonic drone, I would not go into it,” he said, adding that he specialises in supersonic travel and has developed a supersonic business jet.

“If there were any (supersonic UCAVs) by the Americans, Russians or Chinese, I would have pointed the person who asked me to do this to that source.

“I don't think that there is. And if there is, it might be using a different kind of platform, different size, different payloads, different missions.”


With that in mind, Mr Yeo called the Arrow programme “very ambitious”, pointing out that the company will need to spend a lot and achieve supersonic speeds that “might be a little too ambitious” for a loyal wingman concept.

Mr Yeo cited a project involving Boeing Australia and the Royal Australian Air Force to develop a stealthy combat drone that could be paired with manned aircraft and used in intelligence, surveillance and reconnaissance operations.

FILE PHOTO: A model of Boeing's pilotless, fighter-like jet, dubbed "Loyal Wingman", is displayed in Avalon, Australia on Feb 27, 2019. (Reuters/Jamie Freed)

The Boeing drone, called the Airpower Teaming System, conducted its first test flight on Feb 27, two years after a mock-up was officially unveiled at an air show in 2019.

“It has only in the past few weeks made its first flight, and we're talking about Boeing here, one of the biggest aerospace companies in the world,” Mr Yeo said.

“And (the Boeing) loyal wingman’s performance is nowhere near what Kelley Aerospace is talking about.”

Kelley Aerospace is confident that the Arrow will be the world's first supersonic combat drone. (Photo: Marcus Mark Ramos)

Still, Mr Chen said the Arrow programme shows some promise.

While there is a “big difference” between the smaller-scale test as compared to an actual test flight, he said the initial claim of success shows the Arrow is aerodynamically sound.

“It appears that the company has certain expertise in composite materials, so in a way they are not outsourcing too much, I think,” he said, explaining that this could help save costs.

“You also have to look at the pedigree of the company’s board; most of them come from an RSAF (Republic of Singapore Air Force) background. 

“They have good backgrounds in terms of technology, especially in unmanned systems, so this gives some credibility to the project.”

The Kelley Aerospace website lists its chief executive officer as Mr Ian Lim, who spent 31 years in the RSAF as a fighter pilot and retired as its Chief of Staff - Air Staff.

Chief operating officer Andy Tan also served in the RSAF as a fighter pilot for three decades.


Mr Yeo said it is too early to say if the RSAF would have a use for the Arrow, but said it will probably be interested in finding out more.

Mr Chen said the RSAF has always been “way ahead” in unmanned aerial systems, and is the only air force in the region to have a dedicated unmanned aerial vehicle command to look into the development of such capabilities.

An RSAF Heron 1 unmanned aerial vehicle parked at Mountain Home Air Force Base in 2019. (Photo: Aqil Haziq Mahmud)

“As the entire Singapore Armed Forces is looking at a manpower crunch and smarter technologies, it's not surprising that unmanned systems will be one of their priorities on the table,” he said.

“So I think it is a natural way for the RSAF to move into UCAVs, be it either propeller or jet engine driven.”

READ: Most of F-35 fighter jet cost and design issues have been resolved: RSAF chief

RSAF chief Major-General Kelvin Khong announced in 2020 that it was studying new unmanned aerial vehicle concepts and will announce plans to renew these capabilities "in time".

In particular, Mr Chen pointed to the RSAF’s plan to get four F-35B fighter jets by 2026 with an option to buy eight more, highlighting that these jets are able to “talk” to unmanned systems via data link.

“It will be an interesting pairing between the F-35 and any unmanned system that we might have,” he added.

Source: CNA/hz


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