Tag Archive for: aircraft

More F-35s, more tankers: a reliable way to strengthen Australian deterrence

If the Chinese navy’s task group sailing around Australia a few weeks ago showed us anything, it’s that Australia has a deterrence gap so large you can drive a ship through it. Waiting for AUKUS or hoping Australia’s troubled shipbuilding program will deliver—in the 2030s—is a recipe for annual panic about grey zone coercion as Chinese deployments become routine.

Boosting our air combat capability is the fastest way to address Australia’s deterrence gap. That requires two things: more combat aircraft and more airborne tankers.

For decades, received wisdom has been that 100 fighter aircraft were enough for Australia. The logic was vague and came from the Royal Australian Air Force’s four fighter squadrons retaining different mission specialisations. Given multi-role capabilities and sensor fusion of modern aircraft, this specialisations argument is outdated.

So, can 100 aircraft provide credible deterrence?

Currently the RAAF has 72 F-35A Lightnings, 24 F/A-18F Super Hornets and 12 EA-18G Growlers (electromagnetic attackers), for a total of 108 combat-capable aircraft. The jets are supported by seven A330 MRTT tanker-transports (called KC-30As by the RAAF).

Combat readiness is a different story. The Australian Department of Defence doesn’t provide combat aircraft availability numbers, but in 2019 the then US secretary of defense, James Mattis, told the US Navy and Air Force to attain an 80 percent mission-capable rate for combat aircraft.

There are four RAAF F-35A squadrons, including one that’s a training unit in peacetime. Each is allocated 18 aircraft to provide an intended 14 ready for duty while airframes and engines are cycled through maintenance. Two of the 14 are usually held as spares during squadron operations. Therefore, in a crisis the Australian government can expect to call on 36 operational F-35As. The same considerations result in just 16 F/A-18Fs and eight EA-18G Growlers being available

That’s a total of no more than 60 aircraft for a continent the size of Europe—hardly enough.

During surge operations the 60 RAAF combat jets could all be available. But during ongoing crisis operations—such as conducting defensive combat air patrols in the east, north and west of Australia or keeping aircraft next to runways for quick intercepts—the air combat force will quickly run into sustainment problems.

Historical observations of British and US combat aircraft availability show the mission- availability rate can be even worse—for example, due to unreliable parts supply.

On an island continent, air power is the fastest and most efficient means of deterrence. But we just don’t have enough air power.

The Royal Air Force operates 171 combat aircraft and 14 tankers from a land mass 3 percent the size of Australia. The Japanese air force has about 330 fighters and a land mass 5 percent of Australia’s. No other nation seems as committed as Australia to doing so much with so little. The only comparable air force in size to the RAAF is Canada’s, which has 79 fighters.

If Australia is serious about retaining strategic independence, including the ability to credibly deter an enemy, we should increase the size of the RAAF’s fighter force by two squadrons—36 aircraft—and add four A330 MRTT tankers. This should be phased alongside introduction of unmanned semi-autonomous teamed aircraft on a ratio of three uncrewed systems, including some for refuelling, for each additional crewed combat aircraft.

Increasing the fighter force to seven operational squadrons, including the existing dedicated electronic attack squadron but not the training unit, and supplementing it with about 100 autonomous aircraft would grow the RAAF’s combat capability to 240 aircraft before 2034.

A force this size reduces the fragility of the current air combat capability by adding depth through numbers and provides the government with a much broader range of options.

The flexibility of packaged air combat aircraft means they can quickly swing between roles and locations in a matter of hours. Missions can range from air policing and regional assurance to cruise missile defence, maritime strike and counter-air missions. Combat aircraft can be permanently stationed on both the west and east coasts.

The United States is the only country that could supply 36 fighters quickly. The obvious choice is the F-35A, since Lockheed Martin is pushing out 150 fighters of that design annually. Moreover, acquiring aircraft of designs that are already in-service avoids the risks inherent in introducing new types.

Over the long-term, policy settings such backing the development of long-range autonomous and teamed systems can be put in place to make us more strategically secure. But what we need now is an air combat system that helps us understand, decide and act.

The building blocks are in place. The RAAF operates the Wedgetail airborne surveillance, P-8A Poseidon maritime patrol and MC-55A Peregrine electromagnetic surveillance aircraft. Combined with the Jindalee over-the-horizon radar network and Five Eyes intelligence-sharing arrangements, these give us a reasonable understanding of what is happening in our region and where.

But there must be greater emphasis on the action part of the system—the combat aircraft—because deterrence is about the potential for response.

This is an ambitious proposal that would require significant investment in airbase and support infrastructure, particularly in the north and west of the country. But as a realistic, actionable plan that secures Australia’s future it is within our reach. And what’s more, it can be attained in years, not decades.

Bolt from the blue: what we know (and don’t know) about the US’s powerful F-47 fighter

When the F-47 enters service, at a date to be disclosed, it will be a new factor in US air warfare.

A decision to proceed with development, deferred since July, was unexpectedly announced on 21 March. Boeing will be the prime contractor.

The design will have much more range than earlier fighters, both at supersonic and subsonic speed. But it is not even a fighter as it is generally understood. It will be more stealthy. It will be larger, trading dogfight manoeuvrability for reach, and it will be designed to work within a family of systems, many of them unmanned.

Range and speed are defensive attributes, allowing the aircraft to be based farther from Chinese air and missile bases and keeping tankers at a greater distance from interceptors: the air force has backed away from trying to make a more survivable tanker. But range and speed are offensive characteristics, too: while no aircraft can be in two places at once, fast and long-range aircraft can cover a wide area and sustain high sortie rates.

The F-47 is the centrepiece of the US Air Force’s Next Generation Air Dominance (NGAD) effort. The intended fighter design, now the F-47, has also been called NGAD. And the name Penetrating Counter-Air has been attached to it, too.

Former secretary of the air force Frank Kendall characterised NGAD as large and costly, and the F-47 will have retained these attributes. Although Kendall and USAF chief of staff General Dave Allvin raised the idea of a less costly NGAD last year, it never got near the stage of an amendment to the initial request for proposals that was issued in 2023.

Stealth: the F-22 and F-35 are classic applications of bowtie stealth design, their vertical tails causing stronger radar reflections when viewed from the side than from in front or behind. (A graph of this looks like a bowtie.) The problem in the Western Pacific is China’s numerous long-range airborne radars and air-warfare destroyers, which make it next to impossible to avoid being illuminated from all angles.

Expanding the envelope of tailless flight in terms of speed and manoeuvrability was almost certainly a focus of the classified Aerospace Innovation Initiative (AII) demonstration program that led to Boeing and Lockheed Martin AII-X prototypes. (AII was run by the Aerospace Projects Office, specially established within the Defense Advanced Research Projects Agency.)

The USAF sees a program for fighter-like drones, the Collaborative Combat Aircraft (CCA), as an integral part of NGAD, with two or more uncrewed aircraft teamed with each F-47. The Increment 1 CCAs (the General Atomics YFQ-42 and Anduril YFQ-44) are being used to evaluate their role as air-to-air missile carriers, augmenting the F-47’s weapon capability and taking close-range shots; Increment 2 will be designed to target surface emitters—making it an unmanned and attritable wild weasel, a traditional category of aircraft assigned to dealing with air defences. As reported earlier, simulation tests are showing that pilots can manage more than two CCAs.

USAF Lieutenant General Alex ‘Grinch’ Grynkewich, in 2015 and 2016 led the service’s Air Superiority 2030 study that defined NGAD as what was called a Penetrating Counter-Air aircraft. He discussed the reasoning behind Penetrating Counter Air (what’s become the F-47) in a public essay in 2017, by which time AII had been under way for two years.

Grynkewich’s team had started with a range of options, including reliance on standoff weapons and what he termed a ‘Gen6’ concept with F-22-like fighter attributes—which turned out to be far too expensive. The Penetrating Counter Air identity, Grynkewich wrote, avoided both ‘Gen6’ and ‘fighter’ which presupposed ‘a short-range, highly manoeuvrable, supersonic, manned aircraft, typically armed with a limited number of missiles and a gun’.

We know something about the F-47’s size from open-source discussion of its engines.  A 2018 presentation includes a slide outlining the goals of the USAF’s variable-cycle engine program, and it makes a clear distinction between engines of the 200 kilonewton (45,000 lb) thrust class (the General Electric XA100 and Pratt & Whitney XA101) sized for the F-35, smaller ‘scaled core’ engines for what has become the F-47—engines now known as GE XA102 and P&W XA103—and a derivative for retrofit to F-15s and F-16s.

That implies a maximum thrust around 160 kilonewtons (35,000 lb) for the F-47 engine. Given a requirement for less manoeuvre and more range, that points to an aircraft with a loaded weight of about 45 tonnes (much like an F-111, which will please some Australian readers.) But the importance of the adaptive engine is that it allows a supersonic-cruise aircraft to minimise the use of afterburning, even for transonic acceleration, while still being efficient in subsonic flight.

Legions of would-be R. V. Joneses have spent the weekend poring over the F-47 artwork released by the Pentagon. I would advise caution: what we don’t know about its shape is still more important than what we do know, even before we take account of what we do know for certain but ain’t so.

But there are aspects of the artwork that call to mind the work of the late Alan Wiechman, who joined McDonnell Douglas from the Lockheed Skunk Works in the mid-1980s and headed the company’s stealth work until his retirement in 2014. His work included the X-36 tailless prototype, and the Bird Of Prey, demonstrating optical and radar stealth. His obituary in 2023 noted that he had ‘most recently’ been an adviser on stealth to the USAF Rapid Capabilities Office.

As with anything in the United States these days, there is much uncertainty ahead for the F-47. Boeing’s bid was submitted well before new CEO Kelly Ortberg joined, and the company has a painful history of low bidding and poor performance. The requirement may be sound and the technology may be good, but the F-47 is another pull on an overstressed air force budget, and by the time it enters service (not in Trump’s second term) it will face challenges, including whatever F-35X ideas emerge from Fort Worth.

But let’s get back to that surprise announcement on Friday by   President Donald Trump. It came as a surprise for good reasons.

Defying decades of practice, the F-47 was launched by an empty Pentagon C-suite: nominees for the chair of the Joint Chiefs of Staff (CJCS), Air Force secretary, and undersecretaries for acquisition, and research and engineering, are all awaiting confirmation. Defense secretary, infantry major and TV host Pete Hegseth was the sole source selection authority.

Air force leaders had lobbied Trump personally to get his approval for the project, which Kendall put on hold in July. With no CJCS, the lead defense adviser to Hegseth is the director of operations for the Joint Chiefs of Staff, appointed last May: Grynkewich, the author of that NGAD-defining Air Superiority 2030 study.

Was this a Machiavellian plan by Kendall? Delaying the NGAD decision last year looks like a coup, allowing the air force to dazzle the president with secret technology, while talking up the threat of China’s new J-36 to inspire a sense of urgency, permitting Trump to present it as his own idea and calling it F-47. Conveniently, the sceptical Elon Musk, usually omnipresent at big occasions, was busy at a briefing at the Pentagon.

Something old, something new: the very practical rules of Chinese aircraft development

Year-end revelations of two new Chinese combat aircraft designs, the Chengdu J-36 and the Shenyang J-XX, should have put an end to the idea that China’s aerospace and defense industry just copies the West.

Yet sometimes China does produce copies, for good practical reasons. At other times it just does its best with the technology it happens to have available.

Here are some principles that Chinese military aeronautics development follows.

Copy if possible and necessary. The Xi’an KJ-600 configuration copies the Northrop Grumman E-2 Hawkeye’s, down to details. As on the E-2, one of the inboard fins of the four-fin tail has a moving rudder and the other doesn’t. That works on the Hawkeye, so why do it any other way? There’s a reason that the Hawkeye is still in production after 66 years.

KJ-600. Original image source unknown.

Good enough. The Xi’an H-6 bomber is the Soviet Tu-16, 12 days younger than the B-52. But at the age of 55, the design got a complete makeover from the Chinese industry: a new forward fuselage housing a three-member crew, all with ejection seats and glass displays, and a multi-mode radar. 1970s Russian engines replaced the 1950s originals.

The H-6K update and later versions provide the Chinese air force and naval aviation force with a heavy weapons platform with some features that even the forthcoming B-52J (a B-52 update with new engines) cannot match: the Chinese bomber has six wing pylons and an ability to carry an outsize store on its centerline.

Innovate to meet urgent needs. Those stores include not only an air-launched boost-glide weapon but the AVIC WZ-8, one of a group of very innovative Chinese military drones that represent a much more creative culture than what we see in Western aerospace.

WZ-8. Image: Wikipedia.

The WZ-8 is an air-launched, runway-recoverable drone with a blended-delta shape and rocket propulsion. It has (by US intelligence estimates) a speed of Mach 3 at 30,000 metres altitude and a range around 500 nautical miles (900km) including a long gliding descent.

In most respects, it could have been designed and built in the 1950s. But a remarkable feature of the WZ-8, visible on the website of a company specialising in additive manufacturing, is that the entire center-section box, the structural heart of the aircraft, is 3D printed in titanium.

The WZ-8 is the definition of a point design—an inflexible one intended for a single purpose. China regards the ability to attack US aircraft carriers as a strategic goal. And it’s well known that the US Navy relies on its carriers’ ability to move fast and far in the time between when they’re detected and when an attack on them arrives. Jamming and decoys help. The WZ-8’s job is a last-minute reconnaissance sortie to locate the carrier.

Borrowing technology that the West has ignored. The Guizhou WZ-7 Soaring Dragon drone, in service in small numbers, resembles a Northrop Grumman Global Hawk in size and body shape. But it has a four-surface joined wing.

Advantages claimed for the joined wing include combining a skinny wing shape (high aspect ratio, to the aerodynamicists), thinness and sweep. The result is an unusual combination of high speed and low drag.

The joined wing was invented in the US and has been studied by NASA several times, but the space-fixated agency never found budget to demonstrate it in flight. The Chinese designers would have found plenty of open-source data to work from.

 

WZ-7. Image: Wikipedia.

But another drone, Shenyang’s WZ-9 Divine Eagle, has no parallel. It is a high-altitude carrier for two large-aperture radar arrays. Its status is uncertain. It was first seen in 2015 and reappeared on video in late December. The two radar antennas occupy separate fuselages, connected at their front and rear extremities by a wing and canard, with a single engine above the wing. With no crew and high-aspect-ratio wings, the drone can fly higher than a big-cabin crewed platform and has a longer radar horizon.

The WZ-9’s unique shape indicates something about China’s electronics technology. The designers must believe that their radars are so efficient that the cost in weight of carrying two separate units, each with its own power supply, is acceptable. The concept also shows that China can rely on using datalinks alone to operate a complex radar system.

The WZ-9 and WZ-8 typify another trend in China’s technology: firing weapons from one platform (a ship, submarine, aircraft or ground vehicle) by using targeting data from another source. Western experts already believe that China’s growing, diverse fleet of airborne radar systems can be used for direct weapon guidance. The WZ-9 allows weapon-quality guidance to be extended farther without endangering a large crew on an aircraft that cannot defend itself.

Viewed as a group, alongside new combat aircraft like the J-36 and J-XX (J-XDS, according to some sources), these programs also illustrate another, hugely important feature of Chinese aerospace development: the sheer number of new and unique projects.

An engineer who started at Chinese fighter specialist Chengdu Aircraft in the late 1990s could have successively joined new development programs for four combat-aircraft types—the JF-17, J-10, J-20 and J-36. That engineer could also have worked on major upgrades and engine changes for the first three of those. All have entered service or are on track to do so. Working at rival Shenyang Aircraft would provide a similar experience level, with Xi’an Aircraft not far behind.

That engineer’s US counterpart might have worked on one new program from inception to service entry—if he or she had chosen the right company to start with.

It is that growing experience gap, rather than individual systems, that should worry us more than it does.

China’s big new combat aircraft: an airborne cruiser against air and surface targets

The speed, agility, range and stealth of an individual aircraft type are still important, but they’re no longer the whole story of air combat. Advances in sensing, processing and communications are changing military operations.

The Chengdu J-36, the big Chinese combat aircraft that first appeared on 26 December, has been developed to exploit these changes and support China’s strategic goal: to establish regional dominance, including the ability to annex Taiwan by force.

If J-36s can fly supersonically without using afterburning, as the prototype’s shape suggests they will, each will be able to get into and out of battle faster and more safely than conventional fighters and bombers, which cruise subsonically. A high degree of stealth will greatly help J-36s in penetrating defences. Supersonic cruise would also mean each J-36 could fly more missions in a given period.

The design’s big main weapon bays are sized for considerable air-to-surface missiles, which J-36s could launch against such targets as airfields, aircraft carriers and air-defence batteries. With great speed and height, J-36s could also throw inexpensive glide bombs farther than other aircraft could.

The main weapon bays are big enough to carry unusually large air-to-air missiles for engaging aircraft at great range, including vital support units such as tankers and air-surveillance radar planes. Targeting data for this might come from other aircraft, ships, satellites or ground sources. The missiles might also be launched at fighters at ranges that keep J-36s safe from counterattack.

J-36s are themselves likely to be sources of targeting data for other aircraft and for ships, using large passive and active sensors that aircraft of such size can easily carry. They may command aircraft that fly with them. In all this, they’d use radio links that are hard for an enemy to detect.

To call the J-36 an airborne cruiser may not be far off the mark—and may call into question the West’s decision to prioritise development and production of fighters that are, by comparison, mere torpedo boats.

(An earlier article in this series technically assesses the design of the J-36. The type’s designation is likely but not certain.)

For the Taiwan mission, China’s principal opposing force is US-led air power, comprising the US Air Force and the US Navy’s aircraft carriers, with support from Japan, Australia, Taiwan and maybe South Korea and others. Air power from China’s opponents can hinder its maritime and amphibious operations, resulting in slower progress and higher casualties.

So, counter-air capability is crucial for China. This is what the US thinks of as China’s anti-access and area denial capability. It includes surface-to-air weapons, fighters, air-base attacks and the information realm.

To understand where the J-36 fits in, start by considering China’s current force, of which the Chengdu J-20 is the spearhead. The J-20 is fast and stealthy, with good range for a fighter, but its weapon bays are limited to short-range and medium-range air-to-air weapons. Like the F-35, it is more detectable outside its forward quadrant. That becomes a greater vulnerability in a networked environment, where a sensor platform on your beam may not be well placed to launch a weapon but will pass your track to one that is.

The long-range Xi’an H-6 bomber, used as a missile carrier, can launch attacks at air bases throughout the Western Pacific. But its effect is limited to the warheads of up to six costly missiles that must fly far enough to keep their vulnerable launch aircraft safe.

The J-36 combines speed and range with all-aspect stealth. Potential internal loads include such long-range air-to-air missiles as the PL-17, which the J-20 cannot carry internally. Heavier, air-to-surface missiles would be aimed at airfields and warships. It also probably supports the kind of mass-precision attacks made possible by accurate, more autonomous weapons, or—as autonomous technology advances—the carriage of loitering munitions and jammers.

The J-36’s smaller outboard weapon bays might accommodate defensive and support weapons, possibly on extending rails like the J-20’s side bays.

The large transparent side apertures in the forward fuselage could be wide-field-of-view passive warning and cueing systems. But there’s another possibility: if you wanted to integrate a high-energy anti-missile laser into an aircraft, with a hemisphere-plus field of fire but without unstealthy turrets, it might from the outside look like those transparencies. A single optical chain could feed left and right steerable heads under the conformal windows. Cue panic.

Speed is not just valuable for survivability, although it does erode missile engagement envelopes. Even Mach 1.8 supersonic cruise halves flight time and greatly increases sortie rate compared with a subsonic-cruise aircraft.

The US considered developing a supersonic strike aircraft in the early 2000s. But with 9/11 and the cost of the F-35 program, a high-speed project could not get funded. ‘Response time, and cost per target killed, were the two holy grails,’ a Northrop Grumman engineer commented in early 2001. The supersonic aircraft was big and complex, but the sortie generation rate was far higher than that of subsonic alternatives, and fewer aircraft were needed. And it could use cheap, unpowered glide weapons with a stand-off range estimated at 170km from a Mach 2 launch.

Speed on one side of a conflict is an important advantage. If the J-36 can penetrate to threaten bases in the second island chain, forcing the US to move B-21s, B-52s and other high-value assets further back, US strike sortie rate and effectiveness will diminish.

It’s important to keep in mind that the J-36 will be part of a family of systems and a network of capabilities. The appearance over the holiday season of the KJ-3000 airborne early warning and control system, based on the Xi’an Y-20 airlifter, is significant.

China has produced five different airborne radar systems since 2003, more than any other nation, all based on the technology of active electronically scanned arrays (AESAs). It has expanded their role beyond that of forward-passing adversary track data to fighter aircraft. AESA radars can update tracks much faster than a rotating-antenna radar, so these systems can provide guidance-quality midcourse updates to missiles.

Compared with the propeller-driven KJ-500, the KJ-3000 can be moved faster and farther forward to support an operation, and it can fly higher for greater sensor range. Working with a KJ-3000, the J-36s could launch missiles while remaining radar-silent.

If its speed and stealth allow it safely to get close to the enemy, a J-36 itself will be able to provide targeting data to other weapons, such as missiles launched by H-6s that prudently stay well behind it. It will also be the command and control hub for other aircraft, crewed and uncrewed. If it is a two-seater, the second crew member will likely be a force manager.

As for how to classify the J-36, too many people have rushed to call it a ‘sixth-generation fighter’.

The ‘fifth-generation’ term, invented in Russia, was picked up by Lockheed Martin as a marketing tool in the early 2000s. What Lockheed Martin would call 5-gen fighters combine supersonic speed and maneuverability with some degree of stealth. The Chengdu J-20 fighter is fifth-generation by that standard.

But this ‘generation’ taxonomy misleads more than it informs, because combat aircraft designs need not and do not fall into discrete sequential groups of characteristics.

And ‘fighter’, ‘bomber’ and ‘strike’ definitions are getting less clear. Most Boeing F-15s, nominally fighters, have been built as strike aircraft, and the fighter-derived Sukhoi Su-34 is another step down the same path. Designed against air and land threats, the J-36 is even larger than the Su-34. Its size and flight performance put it into its own category, for which there is no name. Maybe ‘airborne cruiser’ will catch on.

A doubtful military revolution: replacing choppers with multirotor electric aircraft

Supposedly, something big happened in the defence world on 12 December. Upstart startup Anduril announced a joint venture with Archer Aviation, one of the leading companies in the industry for making electric vertical take-off and landing (eVTOL) aircraft.

To eVTOL backers, the announcement pointed to replacement of many military helicopters by electrically powered, multi-rotor aircraft, which in cruise would fly as aeroplanes.

But we have every reason to be sceptical. The eVTOL craze has generated an awful lot of talk and minimal achievement even in its original, civilian market.

Archer said that its new defence division was targeting a ‘potential program of record’ from the Department of Defense (DoD). Never mind that there is no such thing: a program of record is not ‘potential’, because, by definition, it is an approved requirement backed by money.

The association with Anduril allowed Archer to raise money that it can use to fund the development of the Midnight, its civilian eVTOL product. Archer and its competitors are spending a lot of cash on building factories and testing prototypes, while working with the Federal Aviation Administration and other authorities to earn safety certification without which they cannot make revenue.

Bulls in the eVTOL business say that the sky is the limit. In a LinkedIn post, Mark Moore—eVTOL guru, long-time personal aviation advocate at NASA and now chief executive of Whisper Aero, developing electric aviation propulsion—notes that ‘Anduril’s deep pockets and DoD positioning enables Archer to have a clear path to impressive DoD products. … Archer will have a clear path to a dual-use military-civil market strategy that directly competes with helicopters in these markets.’

The eVTOL craze started with 2013 remark about Twitter by the entrepreneur Peter Thiel: ‘We wanted flying cars; instead they gave us 140 characters.’ But it was really got underway by Moore as co-founder of Uber Elevate and by the company’s 2016 report that was the first of many to predict that eVTOLs in their thousands would provide zero-emission point-to-point urban air travel at a price comparable with a ground limo.

Not so fast.

You can read eVTOL media all day without running across one awkward fact: after six years and billions spent, no eVTOL has performed a basic VTOL mission, flying 40km out, landing, taking off and returning, all while carrying a representative payload on one charge. The best available batteries are not up to the job.

Archer and Anduril mitigate this problem for defence users by switching to hybrid power, with both batteries and a turbo-generator onboard. But that adds complexity to a system that’s already complex, because the philosophy behind eVTOL aircraft is safety through redundancy. The Midnight ties the 95-year-old record for most engines installed on one aircraft, with 12 motor-prop units in tandem pairs on the wing. A Midnight should be able to lose two engines and land safely.

But six fixed-pitch lift-only rotors and six variable-pitch tilting rotors, generating high energy airflow streams that interact and change with airspeed and tilt angle, add up to a flight control challenge.

Crewed eVTOLs depend on a level of automation that goes beyond the common fly-by-wire technology through which pilots control modern aircraft. Pros from the traditional rotorcraft world point to the long time it takes to get certification for even a conventional helicopter with fly-by-wire. They doubt eVTOL leaders can achieve certification by their 2026-27 target dates.

Still, defence customers might accept a higher level of risk.

But, even so, what will a hybrid eVTOL bring to defence missions?

Designed for very short flights, the Midnight has a cruising speed, 240km/h, no better than that of a helicopter. Multi-rotor advocates claim higher efficiency than a helicopter in cruise, but any such benefits will be offset by a heavier propulsion system.

There are more technical reasons for doubting the military value of eVTOLs. The Midnight’s rotors are about 2 metres in diameter—but, even with 12 of them, the discs they form when rotating have well under half the area of the Airbus H135 helicopter, which has about the same gross weight (2900kg). Higher disc loading means more power is needed to hover (1 to 1.2MW for the Midnight, versus 940kW for the H135) and consequently a powerful, complex downwash field that will kick up much more debris. Who wants that in a military operation?

The Midnight spans 15 metres tip-to-tip, compared with the H135’s 10-metre rotor diameter. That is hardly an advantage in most tactical operations and distinctly not great for operating on warships.

Scaling multi-rotor eVTOL designs up, perhaps to act as airborne 2-tonne trucks, will exacerbate all these issues. Enlarging rotorcraft increases disk loading unless you change the configuration, which is why the CH-47 with its two 18.3-metre rotors rules the heavy-lift helicopter segment.

Going lighter and unmanned? Well, another company, Griffon Aerospace, is already there, with the neat and simple (only four motors) Valiant drone.

It’s early days, and neither sceptics nor boosters are infallible. Let’s see what the mystery ‘program of record’ turns out to be.

The curious case of the MRH90

An Australian Multi-Role Helicopter (MRH 90) flies over Brisbane.Last week saw the release of the latest Australian National Audit Office report into defence acquisitions. In the firing line this time is the multi-role helicopter program. Like most audit reports, the ANAO has carefully unpacked the process behind this troubled acquisition—now over four years late and, like many other audited projects, well ensconced on the projects of concern list.

But unlike most audit reports, there’s a big gap in this one. The ANAO reports that the Howard government’s decision to acquire the European-sourced MRH90 rather than the American S-70M Black Hawk was taken against the advice provided from Defence. Because those deliberations are covered by Cabinet confidentiality, we can’t be sure why that was the case. My suspicion is that the deciding factor was the prospect of greater Australian industry involvement in the European bid. Read more