back to article 45-day drone flights? You are like a little baby. How about a full YEAR?

Defence kit megalith BAE Systems is working on a drone that "has the potential to fly for up to a year before needing maintenance", in a challenge to Airbus' Zephyr being trialled by the Ministry of Defence. The Phasa-35 drone, under development by Hampshire-based firm Prismatic with the backing of BAE Systems, is intended to …

  1. Semtex451 Silver badge
    Windows

    The important question is

    How many buses is a 35m wingspan

    1. DNTP

      Re: The important question is

      As wide as 2.8 non-articulated city buses are long, 1.1 times the width of a Catalina flying boat, 20.6 Smoots.

  2. SkippyBing Silver badge

    45 days vs 365

    I'm curious as to why the Airbus example couldn't do a whole year, I'd have thought if you can survive 45 diurnal cycles then you've got the solar and battery tech sorted to effectively stay up indefinitely.

    I mean stand fast doing it somewhere extreme like North of the Arctic circle.

    1. John 110
      Joke

      Re: 45 days vs 365

      They've got to land it to change the film cartridge (or SD card if you want to be needlessly "modern")

      1. Christian Berger Silver badge

        Re: 45 days vs 365

        Don't be silly, you can just eject the film in a small capsule with a parachute.

        1. }{amis}{ Silver badge
          Coat

          Re: 45 days vs 365

          Back in the early spy satellite days, they did exactly that: Corona (satellite)

    2. }{amis}{ Silver badge
      Coat

      Re: 45 days vs 365

      I would guess the batteries.

      The nominal rating on a given cell is not an absolute, it's a value that it will maintain over a given number of charge-discharge cycles.

      I am guessing that the Airbus unit is using older cell design and thrashing the snot out of them, hence the short lifespan.

      1. rg287

        Re: 45 days vs 365

        I am guessing that the Airbus unit is using older cell design and thrashing the snot out of them, hence the short lifespan.

        Yeah, by the looks of it the Zephyr uses Lithium-Sulphur, the Prisma is Li-Ion.

        That said, the comparison in the article is a bit unfair and lacking in context.

        The Zephyr is a 25m wingspan aircraft that weighs ~50-60kg.

        The Prismatic is a 35m aircraft that weighs ~150kg.

        Shocker, an aircraft that weighs 3 times as much has found an extra 10kg of payload capacity! One would assume that the extra wingspan/solar panel area and enlarged vehicle allows them to generate more lift and thrash a larger pool of cells less hard.

        The next generation of Airbus (Zephyr-T) is getting a stretched wing and touting "year round operations" though not until 2020, so it seems like Prismatic have made the jump straight to the big-brother configuration and leap-frogged Airbus instead of working up through smaller demonstrators.

    3. Peter2 Silver badge

      Re: 45 days vs 365

      It's a good question. If I had to guess, i'd say something on the aircraft is only rated for around about a thousand hours in service (~42 days) with a 10% leeway before it has to have a routine service (which brings you to 1100h /24 = 45.8 days)

      I also suspect that there is a difference between being able to build something that can in theory stay aloft for that long, and building something that the Civil Aviation Authority (or Military Aviation Authority) will let you fly for that long without a routine service to check for airframe fatiuge/damage.

      Or maybe i'm just cynical after being exposed to salesmen for too long. In short, one firm has hardware that flies. The other firm has vapourware that they promise that they could build, and should somebody pay them to do so then it could/should have the performance claimed in their advert.

      1. Anonymous Coward
        Anonymous Coward

        Re: 45 days vs 365

        "routine service to check for airframe fatiuge/damage."

        ISTR that the biggest concern for airframes is pressure cycles. On a long flight duration drone A) there's no pressure cycling to speak of. B) there's probably no pressure vessel C) there's no self-loading cargo to complain if the pressure vessel fails.

        Running an engine for a year straight might raise some concerns, but continuous-duty electrical motors are a thing that exists.

    4. a_yank_lurker Silver badge

      Re: 45 days vs 365

      Airbus is being more honest. Drones will need periodic maintenance, say once every 30 to 60 days of continuous operation just make sure nothing has worn out, shaken loose, is not suffering from fatigue, etc. The maintenance might take a week, depending on what is found.

      1. Anonymous Coward
        Anonymous Coward

        Re: 45 days vs 365

        And of course there is the profit to be made from an over zealous service interval. Airbus still need to pay off the development costs of the A380, and, as Tesco would say, "Every little bit helps"

    5. Anonymous Coward
      Anonymous Coward

      Re: 45 days vs 365

      Those wings look ace at gliding, and gliders are brilliant at losing height slowly. The best competition gliders lose height at 100 ft/minute.

      I'm too lazy to do real research, so let's assume the thin air at that height means it loses height at 200 ft/minute instead. Don't argue. The god of 'pluck random multipliers from thin air' decrees this lazy logic is sound.

      Let's also assume it's allowed to descend from 70,000 feet to 30,000 before some officious minion requires it to land. That will take 3 hours 20 minutes which offers a useful 'buffer' during the night, should the batteries have too little boogie juice to run the engine.

      Then the sun rises and it can climb back up to 70,000 ft during the day.

      Perhaps it's something along those lines which determines the operational time? The battery tech means it loses a little height each day, and eventually officious minion number one gets to press the big flight abort button.

  3. John Smith 19 Gold badge
    Unhappy

    Well it does sound incomparably better. And backed by BAe no less.

    What could go wrong?

    1. Anonymous Coward
      Anonymous Coward

      Re: Well it does sound incomparably better. And backed by BAe no less.

      It cost Billions Above Estimate and didn't have the original functionality promised?

  4. Baldrickk Silver badge

    Looks pretty thin (wings, fuselage)

    And at those heights, you probably would have a hard time making it out.

    It'd be like a U2 but harder to see.

    1. Michael Habel Silver badge
      Trollface

      Re: Looks pretty thin (wings, fuselage)

      It'd be like a U2 but harder to see.

      Also hopefully harder to hear too....

    2. Anonymous Coward
      Anonymous Coward

      Re: Looks pretty thin (wings, fuselage)

      I wouldn't put too much importance in the headline picture; apart from the high aspect-ratio wings, which are to be expected, the only other significant detail it shows is probably incorrect - I can't think of any good reason why the props have been placed so far out on the wings, and quite a few reasons why they shouldn't be placed there.

  5. imanidiot Silver badge

    So??

    NASA already proved this can be done with the Pathfinder, Centurion and Helios programs. Not exactly something new.

  6. Anonymous Coward
    Anonymous Coward

    "...useful payload of 15kg..."

    Spies will ask: How many spare watts of 24/365 electric power is available?

    Preferably at 28 volts DC.

    These spy cameras and C^3 gear don't power themselves.

  7. Daedalus Silver badge

    Hmmm

    Fragile craft, detectable from miles away, hardly moving.

    Yeah, perfect military surveillance craft. It's the U-2 of solar power craft. All it needs is a little missile that can get that high. Oh wait, they already exist.

    1. Sgt_Oddball Silver badge
      Headmaster

      Re: Hmmm

      That would imply the sorts of people they want to watch with this kind of much, much cheaper kit have weapons capable of detecting and hitting the thing....

      Even if they do, it's still alot cheaper to lose compaired to a U2. Also, comparable platforms are already in use but don't have the longevity (think predator or watchkeeper drones) without being lost constantly.... so I'd rather say you're missing the mission profile thinking that it'd be doing high risk spy jobs rather than keeping watch on local nut jobs with guns.

      1. Anonymous Coward
        Anonymous Coward

        Re: Hmmm

        This isn't warzone tech, I'd predict it's mainly going to be used for ubiquitous monitoring on domestic populations. Much cheaper and lower profile than using police helicopters for the job.

        It's a pity they're so focussed on the surveillance role, the platform might also be useful for comms. Think satellite phones, but much, much cheaper to run.

        1. John Brown (no body) Silver badge

          Re: Hmmm

          "Much cheaper and lower profile than using police helicopters for the job."

          I wonder how much the camera/lens combo weighs that could replace a low altitude police chopper and still get the same close up detail? Not to mention the gear for night vision, ie honking bright search lights.

      2. John Brown (no body) Silver badge

        Re: Hmmm

        "Even if they do, it's still alot cheaper to lose compaired to a U2. Also, comparable platforms are already in use but don't have the longevity (think predator or watchkeeper drones) without being lost constantly.... so I'd rather say you're missing the mission profile thinking that it'd be doing high risk spy jobs rather than keeping watch on local nut jobs with guns."

        And with the EU spat over Galileo, it does make one wonder if a fleet of these could be tasked as a SatNav (equivalent) system at significantly lower initial and running costs. It'd probably need a few ground stations so the aircraft can get their own locations. Not much use for overseas adventures though.

  8. Forestman

    Why just military?

    For city police departments they'll be cheaper than helicopter hours. They'll be (un)seen over London, Los Angeles or other large metropolis in the near future.

    1. Anonymous Coward
      Anonymous Coward

      Re: Why just police?

      With enough money, the next Zuckerberg could be taking your sunbathing photos...

      1. TrumpSlurp the Troll Silver badge

        Re: Why just police?

        Well, yes, continuous photography and mapping without needing a satellite would at least ensure that Google Maps would be up to date.

        Speaking of which, when is the next round of StreetView?

        1. Holtsmark

          Re: Why just police?

          With this kind of payload mass and flying at these altitudes, this system is designed to carry communication equipment and little else. Fast communications / internet with no ground infrastructure is the goal. Earth observation payloads (visible light, hyper spectral, radar, lidar) are too heavy, and cloud cover will often obscure the line of sight (except for Radar).

          If the goal had been surveillance, then the system would have ended up looking a lot more like the U2.

        2. Gotno iShit Wantno iShit

          Re: Why just police?

          Speaking of which, when is the next round of StreetView?

          I saw a slurp wagon on the roads of North Yorkshire last Friday. I thought it was a continuous process with a small fleet once a country had been done once.

        3. rg287

          Re: Why just police?

          Speaking of which, when is the next round of StreetView?

          Don't know, but I was passed by a car from Here in a small Staffordshire town a couple of weeks ago.

    2. SkippyBing Silver badge

      Re: Why just military?

      Clouds. At 55-70,000' there's a lot of weather beneath you so the chances of being able to see what you're interested in are pretty low in London, and not great in LA with the coastal fog and/or smog. For long-term surveillance it's not a major issue, for real time following car chases and the like it makes it a non-starter.

  9. Cuddles Silver badge

    Theory vs. practice

    Given the UK military's track record of parking their drones headfirst into the sea, there doesn't seem to be much practical difference between the two. 45 vs. 365 days is irrelevant if you crash it within a couple of hours of takeoff.

  10. Kevin McMurtrie Silver badge
    Paris Hilton

    Curious

    How do you get an aircraft with a 35m wingspan up to 70000 feet without a gust of wind ripping it to bits? Any why are the horizontal and vertical measurements in different units?

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Biting the hand that feeds IT © 1998–2019