back to article DARPA's air-steered X-65 jet heads into production with goal of flying by 2025

The latest experimental DARPA aircraft, which is designed to maneuver without the need for moving parts, is headed to the manufacturing stage and could be flying as soon as next year. The X-65 is being built by Boeing subsidiary Aurora Flight Sciences, who scored a contract with the Defense Department last year as part of the …

  1. Jou (Mxyzptlk) Silver badge

    And the valves?

    What about the valves controlling the pressurized air? Non-moving parts too? If yes: Wanna see the tech!

    1. mirachu Bronze badge

      Re: And the valves?

      My zeroth guess would be magnetic valves. Precisely one moving part per, granularity is a trivial implementation issue.

      1. Anonymous Coward
        Anonymous Coward

        Re: And the valves?

        I doubt that magnetic valves would produce the fine grained control you need to control an aircraft; the valves will almost certainly be more "analogue" than on/off digital. Can this be done with a pure electromagnetic valve, or do you have to use some sort of servo valve?

        1. Dvon of Edzore

          Re: And the valves?

          Although digital proportional valves have long existed, continuously-variable flow can be simulated with on-off PWM to any degree needed. Designing for PWM also allows much faster response to changing conditions than existing mechanical systems which are high-inertia, slow-moving beasts.in comparison.

    2. Dvon of Edzore

      Re: And the valves?

      For non-moving-parts valves, look to fluidics. Not exactly new or unknown.

      https://en.wikipedia.org/wiki/Fluidics

      1. Jou (Mxyzptlk) Silver badge

        Re: And the valves?

        And how are the steering valves of the amplifier example controlled? By a tiny gnome, since lifeforms don't count as "moving parts" :D.

  2. HighHair

    What could go wrong...

    For a start...

    * Complete or partial loss of engine power means limited or no steering whatsoever.

    * Strong cross winds on landing requires instant and precise control.

    * Short landing and and take off requires heavy use of flaps.

    1. Anonymous Coward
      Anonymous Coward

      Re: What could go wrong...

      The valves don't have to be in any way connected to the engine. Also, remember that a plane moving forward automatically has ram air.

      Strong cross winds means you ask for a different runway if possible. You don't have to take runway offered, but then you may have to divert.

      1. jgarbo

        Re: What could go wrong...

        Divert...to a road, field or large garden? What could go wrong?

      2. Anonymous Coward
        Anonymous Coward

        Re: What could go wrong...

        "The valves don't have to be in any way connected to the engine"

        I'm afraid they do, because that's the main source of power on the aircraft There will be an auxilliary turbine for emergencies though.

        1. tip pc Silver badge

          Re: What could go wrong...

          aircraft of the past used bleed valves in the engines to provide compressed air for various systems & cabin pressurisation.

          Newer aircraft designs don't use bleed air, which is what was being remarked.

          https://en.wikipedia.org/wiki/Bleed_air

          https://en.wikipedia.org/wiki/Bleed_air#Bleedless_aircraft

          1. Lurko

            Re: What could go wrong...

            Indeed, but using pressurised air for control isn't that new a thing, the Blackburn Buccaneer first flown in 1958 used pressurised air on control surfaces to enhance performance, meaning it could take off at only 140 mph. Not anything like what DARPA are proposing, but an interesting bit of history.

            That of course was back in the days when Britain built innovative aircraft. Thanks to decades of shit-headed government policies we've barely got a military aircraft industry now.

            1. ectel

              Re: What could go wrong...

              Of course the reduction in Defence spending allows spending on other things that are diesrable to the population, or the reduction in the taxation burden

              Utumatly Polititans tend to do what gets them elected, and that does include spending less, or diferently to the past

              1. Lyndication

                Re: What could go wrong...

                Except the UK has both the highest tax burden for a long time, and the smallest expenditure on things like Welfare and Healthcare.

                It's genuinely the worst of both worlds and it's down to successive administrations' poor management and vision.

      3. Jan 0 Silver badge

        Re: What could go wrong... Ram Air

        I have a hazy recollection that the ram effect can only work down to airspeeds of the order of 300 to 350 mph. That could make an unpowered landing more than a brown pants situation.

      4. david 12 Silver badge

        Re: What could go wrong...

        connected to the engine

        Engine? Who said anything about an engine? It's got no moving parts. Clearly either a rocket or a sailboat.

    2. Kevin McMurtrie Silver badge

      Re: What could go wrong...

      The video shows a small conventional jet in the nose providing power for everything. Assuming that this is simpler and less stressed than a propulsion engine, it should be extremely reliable. The air steering looks vastly simpler than mechanical steering. Still want it more reliable? If the unpowered state is a stable glide, emergency gas canisters could provide emergency landing maneuvers.

      The engineering geek in me in in awe of how simple and effective this kind of a jet plane could be.

    3. fajensen
      Facepalm

      Re: What could go wrong...

      Sure, all those aerospace engineers with decades of experience in high performace programmes were stunned to learn about these hitherto unknown GOTCHA's blocking all progress!

    4. Richard 12 Silver badge

      Re: What could go wrong...

      Your first point is already the case. All large and military aircraft are 100% reliant on the hydraulic pumps and valves, driven by engine tap off, backup genny or ram-air generator.

      So no difference.

      As to the others, one presumes that is the point of the test.

    5. Gene Cash Silver badge

      Re: What could go wrong...

      > Strong cross winds on landing requires instant and precise control.

      That's one of the objectives. We're pretty sure the control design is "instant and precise" but that's one of the things flight test finds out.

      1. Anonymous Coward
        Anonymous Coward

        Re: What could go wrong...

        I think the Harrier proves that this sort of control is possible, so it's a case of proving the design rather than the concept

    6. Headley_Grange Silver badge

      Re: What could go wrong...

      "Strong cross winds on landing requires instant and precise control"

      I am not an aerodynamics expert so excuse me if this is a daft idea but for a conventional aircraft isn't the amount of control you have ultimately limited by the speed of the air across the control surfaces? This aircraft might not have such limitations and therefore have better control at the lower landing speeds.

      1. Nick Ryan Silver badge

        Re: What could go wrong...

        That's how I'm reading it. Lift in aircraft is just the difference in air pressure between two surfaces, mostly the top and bottom of a wing and usually due to flow of air across the fixed part of the wing. Wing control surfaces change the flow of air across the wings resulting in more or less air pressure differential. These air jets can directly modify the air pressure differential and can therefore be used to control lift without relying so much on the flow of air across the wings. One of the key issues with modern planes, particularly those that want to go fast, is managing the amount of lift which is why we have seen variable wing aircraft and fast plane tend to have very swept back wings but through doing so, they are less good at slow speeds. Something like this could help bridge the gap between low and high speed wing profiles.

        That's my non-aeronautical engineer take on it anyway

    7. Lurko

      Re: What could go wrong...

      For a start...

      * Complete or partial loss of engine power means limited or no steering whatsoever.

      * Strong cross winds on landing requires instant and precise control.

      * Short landing and and take off requires heavy use of flaps.

      Actually, the main thing that could go wrong is that the many people who are better at spotting problems than opportunities are heeded.

      Back in 1929 the otherwise brilliant engineer A.A.Griffith told the Air Ministry that Frank Whittle's jet engine was impracticable, the Air Ministry decided to let Whittle's idea go, and although Whittle continued as a private venture, that single bad call cost at least a decade to the development of Whittle's ideas until about 1936. Whilst there would have been other opportunities for things to get messed up by offcialdom, had Griffith supported Whittle, then potentially Britain would have started WW2 with jet aircraft in squadron service.

      1. Anonymous Coward
        Anonymous Coward

        Re: What could go wrong...

        Griffith (who had written "An Aerodynamic Theory of Turbine Design" ) said, after an interview with Whittle, that the lack of materials that could take the stresses and temperatures required for an efficient engine made it impracticable,

        That didn't stop Griffith pursuing, as did Hayne Constant, what was effectively the turboprop alone. And Griffith work leads to British axial flow turbines.

        In "Frank Whittle : invention of the jet" the author says that for Whittle to even get access to Griffith was unusual and shows the Ministry thought it an important enough idea to get Griffiths to look at it. And notes that Griffith said in a letter than a jet turbine would "almost certainly be developed" into a successful engine when the compressor and turbine efficiency improved.

    8. Gordon 10
      WTF?

      Re: What could go wrong...

      "* Short landing and take off requires heavy use of flaps."

      No shit sherlock. Fancy highly paid aeronautic engineers not solving that one up front before some random on the internet points it out......

      1. Tim_the_Unenchanter

        Re: What could go wrong...

        Actually they require increased lift for takeoff, and the combination of lift and increased drag for the landing. On landing, this allows a steeper descent profile with control.

        You are confusing how it is accomplished with what is required. (The same mistake users make when describing software requirements. They tend to present the solution instead of describing the actual problem)

        If this system handles the requirements via a different mechanism, then you don’t need the flaps. We have no way of knowing this from the article.

        Flaps increase lift, with the penalty of increased drag - especially at large flap deployments. The drag is useful in landing, not so much for takeoffs.

    9. Jumbotron64

      Re: What could go wrong...

      To add to the "What Could Go Wrong" thread I took much interest when I read that Aurora will be built in West Virginia and Mississippi. Having been born and raised in one of those states and lived for a few years in the other I can with relative certainty these two things....

      #1 The selection of these two states is purely political. Both of these states are festooned with war machine lobbyists and politicians.

      #2 Economics. Both states are some of the poorest in the nation with some of the worst medical and scholastic systems. Both are chocked full of corruption from both the political, legal and business side of things. Plus...and this is the biggy....both are anti-Union states. Yes...I know....West Virginia has a long storied history of being pro-union if for nothing else but the Coal Industry. But those days are gone.

      Couple these things with the news of Boeing's continuing woes in actually doing the core competency of their reason for existence which is namely making aircraft ( see Boeing 737 Max catastrophes ) in part because they continue to increasingly use non-Union contract labor ( the 737 Max is mostly built by a company called Spirit...not the airline mind you ) and Boeing run non-Union fab sites such as the one in South Carolina. South Carolina....see the above facts I stated above about West Virginia and Mississippi.

      Start connecting the dots. I wonder how long before the X-65 becomes yet another footnote in aviation history ?

  3. Mike 112

    That's a lot of remove before flight covers. Wouldn't want any blocked.

    1. mirachu Bronze badge

      Why would there be "a lot of" covers? Exhaust side likely won't need them and you probably won't need several inlets for any reason. Which reminds me of a feature of airjets that make them superior in at least one way: you can't stall them.

  4. ldo

    Wing-Warping

    The Wright Brothers were the first to achieve controlled powered flight by actually bending parts of the wings.

    Later, Curtiss developed the more modern system of articulated control surfaces built into the wings/tail. But the Wright Brothers claimed that their patent applied to his idea as well. The resulting legal dispute effectively shut down the budding US aviation industry, allowing the Europeans to grab an early lead.

    1. Dagg Silver badge

      Re: Wing-Warping

      From what I understand warping is exactly the same as bending.

      From https://www.thefreedictionary.com/warping

      noun.

      1. The state of being twisted or bent out of shape.

    2. Zack Mollusc

      Re: Wing-Warping

      Ailerons precede wing warping. They were patented in 1868. Is this (and the late-1700s aerodynamic research by Caley) the early european lead to which you refer?

      1. Anonymous Coward
        Anonymous Coward

        Re: Wing-Warping

        Caley also made a toy helicopter that went up to 30m vertically.

        Limited communications and US boastfulness, mean that almost everything was invented there, often decades after it was invented, in national scientific publications and patented elsewhere.

        I personally know of a US jet engine patent that was granted this century, that was effectively a Victorian toy in Europe. (I was heavily lawyered by that company to desist from mentioning this, even though they admitted it was true, once they checked my multiple sources.)

        Anon and no details obviously, but the US patent office doesn't "give a flying f*ck" anyway [pun intended].

        1. JimmyPage
          Headmaster

          Re: US jet engine patent that was granted this century,

          Hero of Alexander created a jet engine in Roman times.

          A lot of Roman engineering and science was never developed because with slaves, they had no need. Which is a warning sign for future generations.

          1. Nick Ryan Silver badge

            Re: US jet engine patent that was granted this century,

            Kind of, but it was more considered an interesting toy than anything useful particular as it was not setup to provide rotational power for anything other than just to rotate the steam chamber itself. [assuming that we're thinking of the same device]

            1. ldo

              Re: Hero Of Alexandria

              The “aeolipile”, I believe.

            2. Martin an gof Silver badge
              Boffin

              Re: US jet engine patent that was granted this century,

              I believe a variant of this steam turbine was used to turn a shaft on which a rope was wound which would open a door. Sure I read that in a textbook many years ago but can't find the reference now.

              Maybe I'm misremembering because this link suggests the doors were operated by an expansion-powered water balance mechanism. Ho hum.

              M.

        2. Bebu
          Windows

          Re: Wing-Warping & George Cayley.

          "Caley also made a toy helicopter that went up to 30m vertically."

          George Cayley I believe also had an unrealized design for a steam powered aircraft which would be an alternate steam punk reality. Imagining a British Imperial Airways stoker and fireman. :)

          He also had a prototype internal combustion engine which used gun powder for fuel but apparently had later considered a flammable vapours. His glider had made credible flights and today I imagine by bolting a small Honda 4-stroke onto his glider it could undertake powered controlled flight.

          1. I ain't Spartacus Gold badge
            Happy

            Re: Wing-Warping & George Cayley.

            "Good morning, my Lords, Ladies and gentlemen. This is your captain speaking. We are awaiting final clearance to depart on this Ryanair flight to Barcelona. We will be taking off, as soon as the Imperial Airways flight ahead of us has cleared the runway.. We are up to full steam. Those passengers in rows 30-50 will be required to go to the back of the aircraft and spend ten minutes each shovelling coal into the boilers. However, it is not too late to upgrade from Stoker Class to our Premium Economy Passenger Class - and your cabin crew will be available to take your payments in bankers drafts, gold bullion or postal orders shortly. For an extra payment of just £20 - you can also have your baggage removed from the coal tender - and placed in the hold with the other passenger's baggage - which is not scheduled to be burned as fuel, unless our flight is unexpectedly delayed for any reason. I see the chimney sweeps have now exited the funnels, there will be a charity collection taken during cabin service in order to fund the Heathrow Infants School for Aerial Chimney Sweeps - for which all donations would be gratefully received." Choo! Choo!

    3. david 12 Silver badge

      Re: Wing-Warping

      The Wright brothers were the first to achieve controlled powered flight.

      They took off, flew, and didn't crash. The "not crashing" part was important. Lots of earlier flight experimental series had ended with the death of the invertor.

      The Wright brothers originated and patented the idea of using linked left-and-right side controls, (which controlled both Roll and Yaw), and which made it possible for a learner pilot to control the airplane without dying.

      Modern aircraft don't have linked Roll and Yaw control -- modern aircraft are stable enough that an experienced pilot can control roll and yaw independently -- but modern aircraft do have linked left-side and right-side control. Even modern pilots in modern aircraft don't fly by individually setting the right-side and left-side "articulated control surfaces"

      Curtis added some new ideas -- the later patent pool included both the Wright and the Curtis patents. "Controlled flight without crashing" was the critical contribution made by the Wright brothers, and their patent claim explicitly included any other mechanism that used linked control surfaces for system control.

      1. Tim_the_Unenchanter

        Re: Wing-Warping

        Some aircraft do, indeed have linked yaw and roll control - Mooney aircraft feature a link between rudder and ailerons.

        There are others. I believe Airbus has a mode where a link can be activated, but I may be mistaken.

  5. Gene Cash Silver badge

    F-104 experience

    The F-104 has tiny widdle wingies, so it has REALLY high wing loading, and it uses blown flaps when landing. These are flaps with engine bleed blown over them for added lift and lower stall speed due to less separation at higher AOA.

    Standard procedure for an engine-out landing in an F-104 is "eject"

    There was a lot of smoking holes and dead pilots in Germany before they realized "eject means eject, no matter how studly of a pilot you think you are" and the joke used to be "how do you get an F-104? you buy a hectare of land in Germany and you wait"

    There was ONE guy at Edwards AFB that had multiple engine-out landings under his belt.

    This is a test program I'll be following closely. It'll be interesting to see how it goes, especially in all the "off nominal" situations.

    1. Martin Howe
      FAIL

      Re: F-104 experience

      An aircraft so bad a former Hawkwind frontman made a record about it: https://en.wikipedia.org/wiki/Captain_Lockheed_and_the_Starfighters

      1. Lurko

        Re: F-104 experience

        An aircraft so bad the US quickly stopped using it, and then Lockheed bribed foreign nations to buy the POS.

    2. hammarbtyp

      Re: F-104 experience

      The Blackburn Buccaneer also had blown flaps and greatly increased take off and landing performance from carriers

      The downside was that the engines had to be run high speed to generate the air flow, meaning a huge air brake was required

      However this was only flight augmentation. The difference being the Bucc could take off and land when the system failed, albeit with decreased performance

      Not sure i would want to rely on such a system for total control. While no doubt it would work, my question would be how it would deal with input output blockage, danger of asymmetrical control due to partial failure and whether the engine would have to run at extended speeds for longer to increasing fuel burn and reduce engine life

      However its an interesting project

    3. Anonymous Coward
      Anonymous Coward

      Re: F-104 experience

      I once worked with a couple of colleagues who helped design an "aftermarket" automatic landing system for the F-104.

      One of the many problems was that this thing would be coming in really fast. Fast enough to be scaring the pilots and making them go around again for a better approach. This increased the already unreasonable odds of them going "Splat" on the runway. Or missing the grab-wires and the safety net deployed by the tower at the end of the runway and running out into the fields.

      Thus, a system was devised that would detect the landing configuration of the controls and the height above ground. When the plane was flying straight, wheels deplyoed, and below 30 meters the system would basically grab the controls and brute-force the plane onto the runway.

      Pilots *hated* that one simple trick!

    4. seven of five Silver badge

      Re: F-104 experience

      > Standard procedure for an engine-out landing in an F-104 is "eject"

      For additional "fun", the F-104 ejects downwards.

      1. I ain't Spartacus Gold badge

        Re: F-104 experience

        For additional "fun", the F-104 ejects downwards.

        To be fair, they did change to an upward firing ejector seat in later models.

  6. Bebu
    Windows

    Germany's F-104 tragic statistics

    "There was a lot of smoking holes and dead pilots in Germany before they realized "eject means eject,"

    The wiki page for the Starfighter has these tragic statistics:

    "Germans lost 292 of 916 aircraft and 116 pilots from 1961 to 1989"

    None of these 116 pilots died in actual combat, I would assume.

    1. John Riddoch

      Re: Germany's F-104 tragic statistics

      The Luftwaffe didn't fly any combat missions between 1945 and 1995 (when it was part of a NATO force in the Balkans) so that's a safe assumption.

  7. t0m5k1
    Alert

    Much skills

    Reading all the comments above it seems like Boeing need to come here to recruit!!

    1. Anonymous Coward
      Anonymous Coward

      Re: Much skills

      Have a downvote for failing to understand the purpose and nature of a discussion forum.

      1. Anonymous Coward
        Anonymous Coward

        Re: Much skills

        Have a downvote for not grasping simple observational humour !!

    2. I ain't Spartacus Gold badge
      Coat

      Re: Much skills

      I hear that Boeing's doors are always open to anyone with good ideas.

      ...My coat you say? Why I'm just getting it...

  8. Arthur the cat Silver badge

    Supermarionation

    Does anyone else think that experimental aircraft are looking more and more like something out of Thunderbirds?

    1. Giles C Silver badge

      Re: Supermarionation

      Is that a bad thing….

      1. Arthur the cat Silver badge
        Happy

        Re: Supermarionation

        Is that a bad thing….

        Nope. [Provided they don't need strings to operate.]

  9. spold Silver badge

    Gaseous emissions

    Forced Air Rudder Thrusting - one heading your way

  10. thondwe

    Formula 1

    Any formula 1 teams looking at this - actve areo - no (external) moving parts? Guess FIA would ban it if Merc came up with it first?

    1. Wellyboot Silver badge

      Re: Formula 1

      Lotus with the 88 model decades ago used airflow and a moving body to increase downforce.

      Banned because it was a lot faster than every one else (any failure mode would have been bad news for anyone in the ballistic path).

  11. keystriker

    It seems like the aircraft has the ability to steer with other means than AFC. In the video they say that sole AFC is possible in high velocity. You can also see a hint of flaps on the tail 'wings'.

  12. StrangerHereMyself Silver badge

    Doubt

    I very much doubt this setup will "reduce mechanical complexity" and "improve reliability."

    In fact, if there isn't huge increase in performance or fuel savings I'd say this experiment is more or less worthless.

    1. Ken Hagan Gold badge

      Re: Doubt

      Performance? Fuel savings? Who cares?

      The goal of an experiment is understanding.

  13. Anonymous Coward
    Anonymous Coward

    “ The production phase will culminate in a flight test of the 30-foot wingspan, 7,000 lb ”

    My jet engine gets 40 rods to the hogs head and that’s the way I likes it. Metric plz. UK site.

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