Airlander 10: The Largest Airship In The World

[chicar]

What A Beauty !!!:
http://www.hybridairvehicles.com/aircraft/airlander-10

[Hurricane Annie]

As enthused as I am about the revival of airship fight- that is not the most aesthetic  article . The shots of the ship in flight are  splendid though

[chicar]

 that is not the most aesthetic  article .

Oddly enought it is not the first modern airship to have choose the ''pig butt'' style. Such airship have been discussed before.

[Newchurch]

The airship is berthed in one of the historic hangars at Cardington (Bedfordshire, England).  The owners are offering 'Airlander club membership' for £25.  One of the benefits is the ability to take a tour of the hangar.

First flight is imminent.  After the first flight, existing club memberships will continue to be recognised as life memberships, but new ones will be only annual memberships.

Life members will have their names inscribed on the hull for flight trials.  I don't know whether steampunk names will be accepted - let's hope so!

More information here:  http://www.hybridairvehicles.com/airlander-club.

Declaration of interest:  I have just bought my membership.  I have no other connection with the airship or its owner.

[Hurricane Annie]

 that is not the most aesthetic  article .

Oddly enought it is not the first modern airship to have choose the ''pig butt'' style. Such airship have been discussed before.

There may be something to the design that is a superior design feature. Though surely there is s more flattering angle to take photos  from, to show the underside and it's working

[Banfili]

Saw this on telly - going to be interesting to see the one they plan to build which is four times the size.

[Hurricane Annie]

The airship is berthed in one of the historic hangars at Cardington (Bedfordshire, England).  The owners are offering 'Airlander club membership' for £25.  One of the benefits is the ability to take a tour of the hangar.

First flight is imminent.  After the first flight, existing club memberships will continue to be recognised as life memberships, but new ones will be only annual memberships.

Life members will have their names inscribed on the hull for flight trials.  I don't know whether steampunk names will be accepted - let's hope so!

More information here:  http://www.hybridairvehicles.com/airlander-club.

Declaration of interest:  I have just bought my membership.  I have no other connection with the airship or its owner.

 They don't give  you a turn at flying it ? That is most unfair

 But seriously  -  that is a pretty sweet deal

[J. Wilhelm]

 that is not the most aesthetic  article .

Oddly enought it is not the first modern airship to have choose the ''pig butt'' style. Such airship have been discussed before.

Actually I've been asked that question, and have already touched on it at the Guild of Icarus meta club:
http://brassgoggles.co.uk/forum/index.php/topic,46795.msg963983.html#msg963983

It's a compromise between structural and aerodynamic requirements.

[Hurricane Annie]

 You did touch on the bottom. there [ sorry sorry sorry]  .  Vintage photos  of  dirigible and hangars  are not always modest to the eye. Unfortunately  aesthetics don't always meet authenticity  and accuracy

[Inflatable Friend]

https://www.theguardian.com/uk-news/2016/aug/24/worlds-biggest-aircraft-crashes-bedfordshire-airlander-10

https://www.sadtrombone.com/


Bit of a crunch, apparently damaged but no injuries. Wonder what impact this'll have on the flight testing. Might be interesting to see what the CAA make of it.

[James Harrison]

Count Zeppelin's early efforts didn't do much better.  

LZ1 flew only three times, longest flight 23 minutes, before being scrapped.  
LZ2 suffered engine failure on its first flight before crashlanding in a field and then being torn apart in high winds.
LZ4 blew up in a thunderstorm on its first flight, 'luckily' whilst on the ground undergoing engine repairs.    
LZ5 crashed into trees during a forced landing, then after being repaired crashed again during a gale...

By that yardstick I feel crashing into a telegraph pole and crushing the gondola a little is hardly the end of the world.

~Addendum~

Things could have been worse.  The other airship to have been built in Cardington's Shed 1, after all, landed on its nose the once too.  On a French hillside.  In a storm.  On fire.

[RJBowman]

The ship made a slow-motion nosedive into the ground on its second test flight:

Airlander 10 crashing into the ground cardington shed airship

OH THE HUMANITY!!!

[J. Wilhelm]

I'm still intrigued to see how they got into that situation.  My impression is that the vehicle nosedived, but accelerated it's tilting as it moved forward.

This is a nearly neutral buoyancy design no? And this being a lifting body design, namely a hybrid airfoil and gas bag, there is a significant surface area between the twin envelopes. Basically a giant fat airfoil cross section. If the angle of attack is sufficiently negative, you can get into a situation of instability (like shooting an arrow with the feathered tail forward), pushing the nose down.  And this process was probably started or aided by a sudden horizontal wind gust, which is a new instability mode not seen in conventional airship designs (heavier than air craft will have a problem with downbursts as well). The question is whether the pilots or the computer control systems understood there was negative lift being generated, and whether it/they knew how to correct that.

[Peter Brassbeard]

Thinking it over, the center of gravity looks like about 45-50% of the way from nose to tail.  But for a wing you prefer CG close to the 25% point for stability, much further forward.  Get some forward velocity, pitch the wrong direction, and those small tail surfaces may not be able to correct.

[J. Wilhelm]

Depends on which type of lifting cross-section you're talking about. In this case you have a whole lifting body, not a traditional NACA airfoil cross-section.

http://images.slideplayer.com/22/6365360/slides/slide_40.jpg

Well yes. Technically, you are talking about the dynamic centre of the aircraft which combines all the forces, including the gravitational forces (centre of gravity) and the dynamic pressure forces (lift/drag) forces, plus in the case of an airship what I'll call "centre of buoyant lift" - so the dynamic centre takes a new definition now. Ideally, at speed, the dynamic centre should be pretty close to the centre of gravity, running behind the centre of gravity with the stabilizers counteracting those momenta like any airplane empennage would.  But if the dynamic centre shifts forward toward the CG, then the stabilizers are no good. They actually will lift in the wrong direction themselves because of the wind speed. Once the process starts, a small change in angle means a greater negative angle of incidence (effective wind angle w/r to airfoil chord), so the tilting force increases even more. The process accelerates quickly (what caught my eye). That is why this is a runaway process. The technical jargon is to say that the craft is unstable. Buoyant or not, this is still similar to an airplane. It's a fat buoyant airplane.


~ ~ ~

Addendum:

But what would cause this to start?

Looking at a video of the first takeoff of the Airlander (US Army version), the stabilizers actually have to push down, to counter-act the combined lift from buoyancy, plus ducted fan lift - the fan lift acting forward from the centre of gravity (about 0:38 in the video - note the fans are almost imperceptibly tilted up by a very small angle). At that point the CG and the dynamic centre are nearly the same -tail stabilizers countering the fan's lift. Buoyancy acting on the centre of gravity. As the aircraft speeds up the lifting body begins producing lift, and the dynamic centre moves back a little (due to increased aerodynamic lift), and there is no need for the horizontal stabilizers to lift the tail (0:49). In fact, at speed they may need to flip and push the tail down, just as a normal aircraft empennage does. When its time to land you will reverse the migration of the dynamic centre toward the CG.

Watch Airlander 10 take off for first time

The question is exactly what happened on the surface distribution of pressure when slowing down at a negative pitch angle.

Airship crash, Airlander 10 crashing into the ground cardington shed airship

If you are slowing down and the pilots are pitching down with stabilizers (also deflected downward to pitch the nose down while in speed), then the lifting body is reducing its overall lift (reduced or even negative angle of incidence for the airfoil), which is what you want - to go down, yes? It seems reasonable to push down with negative lift to bring the nearly neutrally buoyant craft down. The airfoil cross section needed looks a lot more like the laminar airfoil cross section, that is, symmetric with respect to the chord. This airfoil is reversible, and lifts in two directions. The angle of incidence is nearly the same as the angle of attack (actual wind angle with respect to chord).


Reverse (upside down) stall?

Normally, as you slow down, the dynamic centre moves forward to the centre of gravity again (aerodynamic lift change) as aerodynamic lift eventually approaches zero. But if the airflow's boundary layer separated under the aircraft toward the rear (perhaps due to excessive pitch or sudden wind gust), there would be a sudden increase in upward pressure on the aft belly of the aircraft. The dynamic centre abruptly moves back, when you actually expect it to be further forward, and by way of computer or pilot, the tail stabilizers are actually deflected down in anticipation of the "forward" dynamic centre (stabilizers are pushing tail up), which is in the wrong direction. Unless you are aware of the stall and flip them over fast, then just setting the stabilizers to "neutral" will not be enough to compensate for the moment. There is no way you can compensate if you don't know what is happening - with buoyancy and such slow motion pilots/computer may not "feel" the stall the same way they would` in an airplane.

Just a theory...

[Inflatable Friend]

One of the pilots in work took a look, laughed and said "Yes, Windshear is a ****"

Weather is the natural enemy of the airship, but I guess we'll need to hang out for the CAA to write something before we get to hear officially why the crash happened.

Hope it doesn't shake investor confidence, while I sadly think airships are wildly unreliable and impractical for all but the most niche tasks, they are undeniably cool and great to see.

At least it wasn't a big crash, nor on fire.

[J. Wilhelm]

I think the simplest explanation is that the craft "lost its wing"  soon before landing.  (0:13 in the video)  With rotors pushing the nose down and stabilizers lifting the tail, there's nothing else that could happen other than suddenly rotate like a seesaw. The pilot/computer then tried to compensate by tilting the front rotors up (0:17), to lift the nose, but it was too late. This was never a problem for airships before (that I'm aware of), so it's a new mode of failure for an aircraft. This is going to be an ongoing problem for all lifting body airships as they slow down. You need to be prepared for a sudden loss of lift (downward lift that is) as opposed to to a smooth tapering of lift as you approach. Honestly, I'd consider aft tilt rotors with quick rotation capability. The stabilizers are not good enough at that speed (other than starting the problem in the first place)

Very funny to look at though

 But it supports the long standing axiom that takeoff and landing are the two most vulnerable segments of the mission of any aircraft. For the V-22 another type of instability during approach has turned deadly. This because on hybrid aircraft you're depending on too many factors to remain as expected to control your landing.

[Peter Brassbeard]

At least it wasn't a big crash, nor on fire.

It did look a lot more like a bounce than a crunch.  But against the wrong ground that could have easily been a more expensive rip.

[Hurricane Annie]

 

Despite this temporary  set back - I am hanging out for a ride in one

[J. Wilhelm]

Despite this temporary  set back - I am hanging out for a ride in one

After watching the video, I'd like to see some design changes befor buying a ticket. It looks their rear propellers have thrust vectoring, but it's not enough, and the front tilt rotors are very slow and limited in thrust angle. I would have imagined they considered that very near the ground wind speeds could either be zero or gusty, and thus lift in either direction would need to be counteracted or substituted by fan thrust. But I'm not entirely sure about their landing protocol. Having a floating wing is in fact a new idea. It comes with new problems.

[Peter Brassbeard]

A floating wing isn't so new as an idea, but as far as I know this is the first time it's actually been implemented.

[J. Wilhelm]

A floating wing isn't so new as an idea, but as far as I know this is the first time it's actually been implemented.

Oooh!  Thank you, you just contributed to my stories! In fact,  you're right. The idea of aerodynamic lift on a lighter than air craft dates back to the days just after the American Civil War. Solomon Andrews invented a hybrid airship concept where he attached three cilindrical envelopes together to build a lifting plane.  He developed a flight mission which he likened to sailing boats. Andrews may in fact be the father of the dynastat type hybrid airship.

https://en.m.wikipedia.org/wiki/Solomon_Andrews_(inventor)
https://en.m.wikipedia.org/wiki/Hybrid_airship

I'm finishing my history studies on the late 19th C German Federation, but I have yet to explain the origin of the CSAA Alamo/USAS Orca.  Knowing the origin of the Dynastat will allow me to give an origin story to my airship

All I have to do is link Andrews to Austrian military engineers, figure out a way for an arms race between Austria and Prussia,  headed by Bismarck, and substitute the Franco German War (so France will no be immediately defeated - no siege of Paris) during my Franco American battles (Pan Atlantic World War). 

Thank you 

[James Harrison]

The Austrians and Prussians actually fought a war in the middle 1860s to decide which of the two would take a leading role in what ultimately became the German Empire: https://en.wikipedia.org/wiki/Austro-Prussian_War

[J. Wilhelm]

The Austrians and Prussians actually fought a war in the middle 1860s to decide which of the two would take a leading role in what ultimately became the German Empire: https://en.wikipedia.org/wiki/Austro-Prussian_War

Yes, that was one of three wars specifically engineered by Prussia to make Austria look bad.

The first one was against Denmark, and actually was the setup, where Prussia and Austria tried to force the political direction of the duchies of Schleswig and Holstein, by splitting them between the two.

3 Years later, Austria objected to holding the territories without approval from the German Diet, and that was all that Prussia needed as a pretext to wage war against Austria.

The third war was actually waged against France, started with the purpose of exploiting nationalist sentiment not only across northern German states, but also in southern and Catholic states. The latter weakened Austria's influence over a greater Germany.

To cap it all off, immediately after capturing Napoleon III, and laying siege to Paris during the fall and winter of 1870/1, Bismarck set up the coronation of Wilhelm I at the Palace of Versailles (how deliciously insulting that must have been to the French  

Coronation of Emperor Wilhelm I at the Hall of Mirrors in Versailles 1871

Naturally, Austria was excluded from the German Empire, but Bismarck's idea was to keep Catholic control and non-German ethnicities outside of the new German state...

Or as we say in America, Bismarck was a real son of a [young female dog]

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

Otto von Bismarck in 1863

~ ~ ~

Well anyhow, I have to fold all of this into a global conflict. Prince Maximilian of Austria became Emperor of Mexico in 1864 until his execution in 1867, during which the Austro-Prussian war happened. This was directly tied to France's second Intervention in Mexico, where the Federal government of Benito Juarez went into hiding.

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

Emperor Maximilian I of Mexico, 1864

The American Civil War happened between 1861 to 1865, overlapping both the Maximilian Empire and the Maximilian Empire/French Intervention. In real history, Abraham Lincoln would basically have to ignore what was happening in Mexico. In alternate history, the risk of doing nothing would put the existence of the United States in extreme danger.

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

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

United States President Abraham Lincoln 1863

Confederate States President Jefferson Davis 1865

The alternative history set up is to have Emperor Francis Joseph I of Austria give full support to young Prince Ferdinand Maximilian Joseph, as opposed to having the Austrian Emperor forcing Maximilan to sign a waiver where he renounced all nobility privileges in Austria before departing to Mexico (Nice big brother huh? I've known family members like that). Austria would have to be stronger, more organized, including Hungarian territories, and allied with France - the two latter of which are technically possible, because Austria-Hungary reorganized itself in 1867 and was stable enough until WW1.

https://en.wikipedia.org/wiki/Austria-Hungary

Emperor Franz Joseph I of Austria 1865

Then I need the Confederate States to be in absolute desperate condition, but much stronger financially and technologically than they were. I need a Confederate stateman to be bold enough to suggest sacrificing unincorporated (non-states) American territory back to Mexico. Basically, cutting a deal with Maximilian where former Mexican territory is returned to Mexico in exchange for Austria and France joining the war against the United States.

The CSAA Alamo (aka the USAS Orca after the war) is a stratospheric capable (30 000 ft) craft, which could easily be developed as a hybrid aircraft  designed to compete with designs from Solomon Andrew. The reason belong that Solomon Andrews was a northerner, and unlikely to cooperate with the Confederate States. So I need a genius counterpart tied with Austria's industrial and technical base - which if I understand was huge, actually. Someone in the US. Austria/Hungary or Germany would have to develop Duralumin alloys to build airship structures much earlier that in real history.

https://en.wikipedia.org/wiki/Solomon_Andrews_(inventor)

Solomon Andrews 1842

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

My Admiral Wilhelm character will (as a young captain) have to capture the CSSA Alamo in battle over the Desert of Sonora ("Franco American Aerial Battle")eventually turning it into the CSAS Orca.

Admiral Wilhelm at a dinner party in Austin, during his latter years c. 1899?  

Naturally, I need to introduce lots and lots of adorable German/Austrian/Hungarian Luftschiffengel (Airship Angels) airship mechanics and engineers aboard the giant aircraft during the war Again, the Luftschiffengel are Engelfolk, a type of Elf-like 3rd Gender Catholic group from Southern Germany, Switzerland and Austria who are under religious persecution, and whose participation in the war is effectively part of their own diaspora (Englefolk Diaspora) caused by Bismarck's Protestant ideology in Germany.  

Earliest known Daguerreotype of a Luftschiffengel c.1860