Zephyr – a white elephant in the making?

Yesterday, we delved into the omnishambles that was the announcement of the Zephyr contract by UK defence secretary Michael Fallon. Today, we will look at a little closer at the capabilities of the aircraft and what it means for the UK armed forces going forward.

Now the UK defence secretary has finally spilled the beans on the UK’s investment in Zephyr, we at last got an insight into what the MoD actually wants to do with them.

Rather than putting them straight on the frontline for our special forces (as had been suggested by the SDSR), it appears the aircraft will actually be concept demonstrators, seeing if the idea of using persistent high-altitude pseudo-satellites – or HAPS – for the battlefield is actually viable.

Zephyr Landing_004

The UK will buy two Zephyr UAVs made by Airbus (Photo: Airbus)

I have written before on high-altitude unmanned aircraft for our Unmanned Vehicles magazine and, in my opinion, there’s a good and a bad side to this £10 million investment.

This means investment for British engineers and revolutionary British technology based in Farnborough, albeit from what is in essence a French/German company (Airbus). It’s also vital investment for the HAPS technology, particular as other similar projects have stalled in recent years due to lack of resources and interest. UK government money might just be the boost that the technology needs to flourish, and potentially be exported to other countries in the future.

The UK could be at the cutting-edge of a technological revolution and a future HAPS centre of excellence. After all, it has military and civil applications.

And the concept is fascinating – an aircraft that can stay aloft for weeks, or even months, using only sunlight to power it and which can then supply ground troops with communications or surveillance capabilities for an indefinite period. That’s essential when troops are in remote, hostile environments where satellite communications are not guaranteed or your satellites have gone down due to hacking or even an enemy missile attack.

There are a range of aircraft, the expensive unmanned Global Hawk for example, that currently perform this role, but they lack the persistence of Zephyr.

Global Hawk

Northrop Grumman’s Global Hawk unmanned surveillance aircraft (Photo: Northrop)

Nevertheless there are downsides to HAPS as well, which could mean Zephyr is potentially a white elephant in the making.

While solar-powered aircraft with massive wings have been around for several decades now, the technology is still in its early stages and has never been adopted operationally by either a military or a commercial entity. The likes of Facebook and Google are attempting to change that in the commercial world with their respective projects, but these are still in the early phases and have yet to really mature.

NASA famously experimented with flying solar wings back in the 90s and 2000s, but their most ambitious project, named the Helios, plummeted into the Pacific Ocean back in 2003. Other company’s attempts to develop a HAPS-type aircraft, including Boeing’s Phantom Eye and AeroVironment’s Global Observer, have also come to a standstill due to a lack of investment.

One issue is the fact that flying solar wings cannot carry a great deal in terms of payloads. The Zephyr, for example, weighs a mere 50kg meaning any surveillance or communication payload has to be equally light in comparison. But there is a distinct lack of lightweight payloads, such as optical cameras and data links, that can perform well at 70,000ft (the Zephyr’s operating altitude).

With its Global Observer aircraft, AeroVironment ditched the solar flying wing concept that it had developed for NASA. I recently spoke to AeroVironment and this following quote expanded a little on the problem with solar power:

‘Throughout the course of the [NASA] programmes as we gained a great deal of experience with solar electric airplanes. We concluded, based on the efficiencies of solar technology and battery technology, that maintaining altitude anywhere in the globe was not possible without some other kind of energy technology.’ 

AeroVironment looked to a liquid hydrogen-fuelled propulsion system instead, powering four high-efficiency electric motors. If liquid hydrogen isn’t your thing, there is always good old-fashioned turbofan. Global Hawk, to use it as an example again, is powered by a huge Rolls Royce turbofan that allows it to fly in the stratosphere with a payload capacity of 1,360kg for over 30 hours.

For the time being at least, with the popularity of the Global Hawk it looks like governments are choosing payload capacity over persistence when it comes to high-altitude assets. The UK is seemingly doing the opposite.

So while it’s great to see the UK invest is revolutionary technology such as Zephyr, the only real question is: do we need it and will it ever be used?

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