The Air­lan­der is go

If you thought air­ships had their day back in the early 20th cen­tury, think again. The fu­tur­is­tic Air­lan­der is set to revo­lu­tionise and ex­ploit hy­brid air­craft op­por­tu­ni­ties — and it’s Bri­tish

Pilot - - CONTENTS - Words Robin Evans Pho­tos Hy­brid Air Ve­hi­cles

Can the Air­lan­der carve out a niche for it­self as a hy­brid work­horse, 100 years af­ter the first air­ships flew?

In a mas­sive hangar in the Bed­ford­shire coun­try­side, a gi­ant is awak­en­ing. The Air­lan­der is claimed to be ‘the world’s most in­no­va­tive, prac­ti­cal and com­mer­cially use­ful hy­brid air­craft’. It is the cre­ation of Hy­brid Air Ve­hi­cles (HAV), a Bri­tish com­pany born of decades of re­search into lighter-than-air (LTA) tech­nol­ogy, in par­tic­u­lar by the late air­ship pi­o­neer Roger Munk. Its unique de­sign was patented in 2001 and re­alised in a $300 mil­lion part­ner­ship between HAV and aero­space gi­ant Northrop Grum­man. Then branded the Long En­durance Multi-in­tel­li­gence Ve­hi­cle (LEMV), it was in­tended for ‘un­blink­ing eye’ long-range surveil­lance for the US Army, oper­at­ing in hos­tile the­atres such as Afghanista­n.

It flew only once, in New Jer­sey in 2012, be­fore the United States econ­omy stalled and all rights to the project were bought back by HAV. Af­ter bud­get cuts killed the pro­gramme, the LEMV and all test data were im­pounded in the US un­der In­ter­na­tional Traf­fic in Arms Reg­u­la­tions. Once re­leased, the project team had only a tiny win­dow to de­vise a way to pack up their ve­hi­cle and va­cate the premises. The project re­turned home to Card­ing­ton, Bed­ford­shire in 2014, since when a

grow­ing work­force−now 100-strong−has been re­assem­bling and test­ing this spe­cialised air­craft, mas­ter­ing the tech­ni­cal chal­lenges re­quired to pro­pel the project to com­mer­cial suc­cess. The ob­ject of these in­tense labours has been hid­den be­hind some ex­tremely large 470-tonne doors but is about to be­come very vis­i­ble, with the first UK test flight due at around the time this edi­tion of Pi­lot ap­pears. In the 1970s, Barnes Wal­lis, chief de­signer of the R100 air­ship and a lead­ing ex­po­nent of LTA tech­nol­ogy iden­ti­fied key is­sues to re­solve to un­lock its full po­ten­tial: im­proved fab­rics, thrust vec­tor­ing, bet­ter flight con­trols and com­pos­ites. Since then, we’ve been wait­ing for tech­nol­ogy to catch up−the Air­lan­der would have been im­pos­si­ble even a decade ago. “The tech­no­log­i­cal prob­lems with air­ships that have stopped them rul­ing the skies have been grad­u­ally ticked off,” says HAV Tech­ni­cal Di­rec­tor Mike Durham. “Ad­vances in ma­te­ri­als, avion­ics and aero­dy­namic de­sign mean that we have over­come the lion’s share of these ob­sta­cles.”

The Air­lan­der de­parts from tra­di­tional air­ship con­struc­tion in key ar­eas. It is less than half the length of 1930s leviathans like the Hin­den­burg but, at 92 me­tres long and

26 me­tres high, it is the world’s largest air­craft, dwarf­ing the A380. Gone are the heavy, in­ner frame­work of gird­ers and flammable hy­dro­gen bags, re­placed by a self-sup­port­ing en­ve­lope filled with he­lium.

Unique de­sign

The Air­lan­der is uniquely po­si­tioned to op­er­ate ef­fi­ciently and sus­tain­ably between the he­li­copter, aero­plane and Un­manned Aerial Ve­hi­cle (UAV), hence the term hy­brid. So rev­o­lu­tion­ary is the con­cept that HAV is in the un­usual po­si­tion of dis­cussing with EASA how to ap­ply reg­u­la­tions set in place for both air­ships and aero­planes: the Air­lan­der is not quite ei­ther. The de­sign avoids the ex­pense and main­te­nance in­ter­vals of a he­li­copter as there is no sin­gle stress point at the main ro­tor.

The ‘free lift’ of buoy­ancy per­mits a manned en­durance of days, plus a much lower car­bon foot­print and noise sig­na­ture. With a ten-tonne pay­load it ex­ceeds the lift­ing ca­pac­ity of a tra­di­tional UAV or ruggedi­zed aero­plane. It does not re­quire a run­way, or even a pre­pared sur­face; ice, water and desert are no longer off-limits which opens up more hos­tile parts of the globe. It is the only type of

long-range ve­hi­cle suited for door-to-door lift­ing or mon­i­tor­ing operations with near zero in­fra­struc­ture. The phrase to de­scribe all these at­tributes rolled into one hy­per­ef­fi­cient plat­form is ‘game-chang­ing’.

Al­though lux­ury trans­port is one pro­posed use, the Air­lan­der is par­tic­u­larly suited to more rugged en­vi­ron­ments: for ex­am­ple disas­ter re­lief, min­ing, re­con­nais­sance, sur­vey­ing mine­fields and en­vi­ron­men­tal mon­i­tor­ing. De­liv­er­ies to com­mu­ni­ties in the Northwest Ter­ri­to­ries of Canada or tak­ing heavy in­fra­struc­ture like wind tur­bines and gen­er­a­tors into re­motest Aus­tralia or Scan­di­navia all be­come pos­si­ble. It can land di­rectly on-site, not de­pen­dent on the near­est large air­port. Head of Part­ner­ships, Chris Daniels con­firms the po­ten­tial is huge: “We have been ap­proached by some­one who wanted to use the ve­hi­cle to ob­serve gi­ant squid off the coast of Antarc­tica. Be­cause the Air­lan­der can take off and land any­where and stay air­borne for days, peo­ple will find amaz­ing ways of us­ing it.” The Air­lan­der is also scal­able. In line for de­vel­op­ment is a larger, fifty-tonne pay­load su­per-lifter that will un­lock a key met­ric in air trans­porta­tion: cost per tonne-kilo­me­tre. Anal­y­sis has shown that the Air­lan­der 50 could un­der­cut fixed­wing, ro­tary cargo and ‘Ice Road Trucker’style haulage into new fron­tiers. Imag­ine a min­ing com­pany slash­ing the costs as­so­ci­ated with open­ing a new site in re­mote ter­ri­tory; in­fra­struc­ture can be lifted di­rectly in by ISO con­tainer and raw ma­te­ri­als re­turned, never need­ing to build a road.

This is both an en­gi­neer­ing dream and sus­tain­able en­ter­prise. In­de­pen­dent as­sess­ment sug­gests a $50 bil­lion mar­ket over the next two decades and 600-plus op­por­tu­ni­ties to sell Air­lan­der vari­ants across three ar­eas: pas­sen­ger, cargo and air­borne plat­form. HAV is con­sid­ered mar­ket leader in this tech­nol­ogy by years and aims to be in profit with a proven ve­hi­cle in­side several years. Such an un­usual pro­to­type prompted equally in­di­vid­ual fi­nanc­ing−over £2 mil­lion has been raised via crowd­fund­ing, with more from busi­ness an­gels, green tech­nol­ogy grants and ven­ture cap­i­tal. Per­haps the most prom­i­nent ex­po­nent is one of our own, Iron Maiden’s Bruce Dickinson; ex­actly the sort of en­thu­si­as­tic char­ac­ter this fledg­ling project needs. It was Dickinson who in­tro­duced me to footage of the maiden test flight at an event in 2013−search for ‘LEMV Lake­hurst’ to see the same.

A spe­cial place

Card­ing­ton has spe­cial sig­nif­i­cance: it was from these mam­moth hangars, now 100 years old, that the first air­ships emerged pur­su­ing a dream to con­nect the Em­pire. Im­mense in sil­hou­ette, with a floor space of five acres each, these Grade II listed green giants were the only ob­vi­ous ev­i­dence of a once mighty in­dus­try, both par­ties hav­ing seen bet­ter days. Less

ob­vi­ous ev­i­dence can be found in Card­ing­ton it­self. The vil­lage sign proudly dis­plays an air­ship and, more poignantly, in the church is a memo­rial and the tat­tered en­sign sal­vaged from the wreck­age of the R101 in Beau­vais, France in 1930. Once listed on the at-risk his­toric reg­is­ter, the iconic hangars have been re­stored re­cently, a multi-mil­lion pound com­mit­ment to the re­birth of both the spir­i­tual home and UK pro­duc­tion of air­ships. Even liv­ing lo­cally, I was un­aware of what was un­fold­ing, un­til the first signs of restora­tion be­came vis­i­ble when the project re­turned in 2014.

HAV main­tains that its pres­ence here is more prac­ti­cal than nos­tal­gic. A venue of suf­fi­cient size is needed and Card­ing­ton is ideally po­si­tioned on the ‘skills cor­ri­dor’ between con­tribut­ing part­ners: Cran­field Univer­sity per­formed the aero­dy­namic test­ing and For­ward Com­pos­ites of Hunt­ing­don as­sists with the struc­tures.

Aware­ness is slowly grow­ing, fu­elled by the in­no­va­tive Air­lan­der Club. Cur­rently over 2,000 mem­bers re­ceive news up­dates and have their names sten­cilled on the hull. Sup­port­ers are wel­comed on reg­u­lar ‘hard hat’ hangar tours, led by project staff and in this way you too could end up at Air­lan­der HQ.

Meet Mary

In­side the cav­ernous Hangar One, there’s a quiet, in­tense at­mos­phere. ‘Mary’, as the team af­fec­tion­ately call her, was re­in­flated in late 2015. Footage of the ini­tial he­lium in­fla­tion is eerie and impressive: some­thing so vast, float­ing un­sup­ported in mid-air. Re­fer­ring to the re-in­fla­tion, Mike Durham says, “It’s very sat­is­fy­ing for the team and me to get an­other mile­stone un­der our belts. We’re hugely ex­cited about the forth­com­ing Air­lan­der first flight this year.”

Work is cur­rently fo­cussed upon the fi­nal stages of the re­turn to flight pro­gramme, con­nect­ing com­po­nents to the hull and engine test­ing, all geared to­wards flight this spring. With skilled labour and decades of per­sis­tence, the UK air­ship in­dus­try, largely dor­mant for al­most half a cen­tury, is be­ing slowly re­built one sig­nif­i­cant mile­stone at a time.

See­ing Mary up close, even in the con­text of these hangars is oth­er­worldly… al­most alien. Imag­ine a block of flats ly­ing prone but an­chored in place with concrete blocks, just in case.

There are several ant-like sub-as­sem­bly teams work­ing in par­al­lel around the hull. In­dus­trial fans cy­cle on and off, briefly

Work is fo­cussed on the fi­nal stages be­fore flight test­ing starts in spring

in­ter­rupt­ing dis­cus­sion. This, along­side the ar­tic­u­lated trailer of gas cylin­ders parked out­side, is the life-sup­port sys­tem un­til the hull is sealed. With Mary fully in­flated but still be­ing worked on, par­tial buoy­ancy is care­fully con­trolled with a vari­able air/ he­lium fill. In­ter­nal vol­ume is 38,000 cu­bic me­tres, about fif­teen Olympic-sized swim­ming pools.

The hull is a triple-ply lam­i­nate of heat-welded pan­els, a few mil­lime­tres thick: a strong in­ner weave of Vec­tran (a Kevlar de­riv­a­tive) with a tough outer coat­ing of Ted­lar. Sand­wiched between is an im­per­me­able, he­lium-re­tain­ing My­lar slice. He­lium is safe; it is em­ployed in cryo­gen­ics (cool­ing the Large Hadron

Col­lider) and tech­ni­cal div­ing mixes. It is a tiny mol­e­cule, used as a tracer in in­dus­trial leak de­tec­tion, so the hull must be ab­so­lutely he­lium-tight. How do you test a newly-in­flated pro­to­type for leak­ing he­lium? Head of Pro­duc­tion, Stu­art Far­rell com­pares it to an enor­mous bike in­ner tube... out came the cherry pick­ers and pres­sure wash­ers in search of bub­bles. In op­er­a­tion, a small top-up is en­vis­aged on an an­nual ba­sis only.

Stan­dard ter­mi­nol­ogy be­comes ab­stract when dis­cussing such an un­usual cre­ation. It sits on long, in­flat­able skids, in­tended to be sucked in once air­borne and blown out again for land­ing. In pro­file, it has that bul­bous, blimp shape but is much wider. From ei­ther end this re­veals it­self as two large hulls with a smaller lobe between. High above is a curved up­per pro­file, key to the unique aero­dy­namic de­sign. The hulls ta­per rear­ward, ac­com­mo­dat­ing newly-in­stalled car­bon-com­pos­ite tail bat­tens. These will re­ceive the tail cones and rear en­gines, fi­bre-op­tic ca­bles for the con­trol sys­tem are coiled ready in place. A for­ward pair of en­gines will be mounted upon py­lons stitched into the hull fab­ric, whilst two pairs of 9 x 11me­tre car­bon fi­bre fins stand up­right along­side.

The nearby Mis­sion Mod­ule houses the flight deck and at­taches to a pay­load beam that runs the length of the cen­tral lobe. Any other pay­load can also be slung here, with the fuel tanks at­tached at the rear. Mary’s of­fi­cial des­ig­na­tion is Air­lan­der 10, re­flect­ing the in­tended pay­load ca­pac­ity in tonnes. A va­ri­ety of Mis­sion Mod­ules can be de­signed and at­tached de­pend­ing upon the in­tended use, just like Thun­der­bird Two− an­other gi­ant multi-role sup­port ve­hi­cle, if a fic­tional one. There’s a sense of sci­ence-fic­tion rapidly evap­o­rat­ing.

Propul­sion comes from four 350hp Thiel­ert tur­bocharged V8 diesel en­gines, al­low­ing a planned ceil­ing of 20,000 feet and a cruise speed of eighty knots. The for­ward en­gines vec­tor thrust only up or down, to avoid blow­ing di­rectly into the side of the hull, while the rear pair have dis­tinc­tive tri­an­gu­lar fins that co­or­di­nate vec­tor­ing in any plane. In re­con­nais­sance ‘loi­ter’ mode the Air­lan­der was de­signed to op­er­ate on one engine, so in an emergency could fly af­ter the loss of three. With a loss of all en­gines, it would still glide/float un­der con­trol to land on any sur­face. Just for­ward of the flight deck is the nose hard-point; a key evo­lu­tion. Air­ships of old docked nose-first to a tall mast, re­main­ing high off the ground to pre­vent crush­ing the un­der­slung gon­dola−an un­wieldy ma­noeu­vre re­quir­ing a small army to pin them to terra firma. The mast atop the Em­pire State Build­ing, it­self an icon of the hal­cyon air­ship era, was de­signed for this pur­pose. The Air­lan­der will con­nect to a small, truck-mounted mast, free to align into wind, then power it­self onto the ground and re­duce buoy­ancy to be­come heav­ier-than-air. In the po­ten­tially hos­tile en­vi­ron­ments it is in­tended for, even with with such a large frontal pro­file, it will en­dure winds of 80kt once docked.

Propul­sion comes from four 350hp Thiel­ert tur­bocharged V8 diesel en­gines

The hull de­sign gen­er­ates 60% of the lift­ing force via he­lium (aero­stat­i­cally) and up to 40% via the cam­bered up­per sur­face (aero­dy­nam­i­cally). Part­ner­ship Di­rec­tor, Chris Daniels ex­plains that above 20kt the wing-like pro­file be­gins to gen­er­ate its own lift and that a fur­ther 25% can come from the vec­tored thrust of the en­gines.

What is that!

Away from the hive of ac­tiv­ity, Chief Test Pi­lot Dave Burns, at the con­trols for the maiden LEMV test in 2012, is busy in the new sim­u­la­tor. Un­der­stand­ably fo­cussed on the 200 hour flight test pro­gramme, he ex­plains: “For the first flight, Air­lan­der 10 will fly up and down the val­ley between Card­ing­ton and the A1, where it is mostly farm­ers’ fields. We’ll take it to about 3,000 feet, later it will go up to 10,000. Peo­ple will be able to see it for miles and I ex­pect many will think the aliens are land­ing!” Dave likens the Air­lan­der to a ship in flight: “Fly­ing it is more like sail­ing, in that things hap­pen at a lower speed. You need to be think­ing ahead. Any ad­just­ment takes a mo­ment to have an ef­fect.” It does how­ever take off more like an aero­plane. “The nor­mal method is to per­form a rolling take­off, just like a fixed-wing air­craft. If an engine fails or there is any other sig­nif­i­cant fail­ure be­fore the V1 & Vr of thirty knots, the take­off is aban­doned. Above thirty knots the take­off is con­tin­ued and the climb-out can be safely ex­e­cuted in terms of ob­sta­cle clear­ance and di­rec­tional con­trol in case of engine fail­ure.” Reg­is­tered G-PHRG, Mary will re­main at Card­ing­ton as the demon­stra­tor, while the data re­turned by the test pro­gramme will be fed back into the even­tual, type-cer­ti­fied model.

Al­though the flight deck it­self is still be­ing as­sem­bled, the sim­u­la­tor is an in­stantly recog­nis­able glass cock­pit, a side-stick sit­ting in the right hand with thrust levers in the left. The over­head panel houses an or­derly ar­ray of square push­but­tons and cir­cuit breakers for fuel pumps, buoy­ancy con­trol, en­gines, electrics and fuel. Out­board of the thrust levers lies a fifth lever for engine vane de­tents, akin to flap po­si­tions. A switch slaves ex­ter­nal cam­eras to a mon­i­tor, as all en­gines will be in­vis­i­ble and in­audi­ble to the pi­lot sit­ting be­neath the hull.

In­ter­nal bal­lonets have been used in con­ven­tional air­ships for some time and the Air­lan­der is no dif­fer­ent. The hull is com­part­men­talised with four of these com­po­nents−smaller, air-filled in­ner bal­loons that are used to con­trol pres­sure and, in the case of the Air­lan­der, fore and aft trim.

Hull pres­sure is around 0.2psi, which sounds very low to hold up such a struc­ture, but is all that is re­quired with such a vol­ume of he­lium. Key to the

self-sup­port­ing struc­ture is skin ten­sion, a func­tion of pres­sure and ra­dius. “We have lit­tle pres­sure but lots of ra­dius. I can walk along the top of the hull and I sink in just half an inch, so it’s a very stiff struc­ture”, ex­plains Mike Durham.

In­no­va­tion and chal­lenges

Such a rev­o­lu­tion­ary de­sign has been achieved through ‘hor­i­zon­tal in­no­va­tion’, i.e. bor­row­ing tech­nol­ogy from other in­dus­tries. Com­mu­ni­ca­tions in­spired the dig­i­tal con­trol net­work; the in­ter­con­nec­tion of flight deck, flight con­trols and en­gines is via ‘fly-by-light’ fi­bre op­tics rather than elec­tri­cal fly-by­wire. Fi­bre op­tics func­tion bet­ter over such a large ve­hi­cle and are highly re­sis­tant to elec­tro­mag­netic in­ter­fer­ence. Trans­duc­ers at the con­trols emit sig­nals that are digi­tised, en­coded into light pulses and sent to elec­tri­cal drive units around the fuse­lage. The hull ma­te­rial is a prod­uct of Amer­ica’s Cup sail tech­nol­ogy−a light but in­cred­i­bly strong fab­ric, heat-welded by US firm ILC Dover, known for their NASA space­suit pedi­gree.

“Eighty per cent of this air­craft is made by Bri­tish com­pa­nies and we are try­ing to stay as Bri­tish as we can,” says Mike Durham. “Look at the UK aero­space in­dus­try today. Pre­dom­i­nantly, we make bits for other peo­ple’s air­craft. This is a Bri­tish busi­ness that makes com­plete air­craft.”

Many chal­lenges have been over­come to re­pur­pose a ve­hi­cle orig­i­nally in­tended for the mil­i­tary. How­ever, a mil­i­tary pedi­gree has ad­van­tages: the Air­lan­der is in­her­ently dam­age tol­er­ant, mak­ing it a very safe propo­si­tion for civil­ian ap­pli­ca­tions. It is more ro­bust than you might imag­ine; the com­part­men­tal­i­sa­tion of the hull al­lows mul­ti­ple punc­tures with­out com­pro­mis­ing buoy­ancy. That low dif­fer­en­tial pres­sure avoids ex­plo­sive dam­age and even when the hull is holed, the gas will only ooze out, as proven in de­struc­tive test­ing.

”Eighty per cent of this air­craft is made by Bri­tish com­pa­nies” — Mike Durham, HAV

He­lium is an in­ert el­e­ment. As Bruce Dickinson ob­serves, “Peo­ple say, God, the Hin­den­burg! But on this you are fly­ing the world’s big­gest fire ex­tin­guisher.” Against the his­tory of the air­ship, it is per­haps go­ing to be a bat­tle to turn around per­cep­tion, as Chris Daniels ad­mits, “One of the big­gest chal­lenges we’re go­ing to have is to tell the world just how safe this is.”

For an in­ert el­e­ment, he­lium avail­abil­ity is more volatile. This pre­cious re­source could be the next crude oil: a high-de­mand com­mod­ity that can­not be man­u­fac­tured, only ex­tracted from nat­u­ral wells. His­tor­i­cally con­trolled by the United States for air­ships and the space race, new plants in Qatar and Al­ge­ria now meet a grow­ing thirst, driven by in­dus­trial cryo­gen­ics. Prices have sta­bilised but es­ti­mates of peak sup­ply vary greatly.

De­spite the phys­i­cal scale in­volved, the things that re­ally strike are the in­tan­gi­bles: the quiet in­ten­sity, vi­sion and en­thu­si­asm slowly pro­pel­ling this project to­wards com­ple­tion, just like Con­corde, hov­er­craft and the Har­rier−other in­con­gru­ous Bri­tish in­no­va­tions. In the same vein, it is re­mark­able what has been achieved over both long and short timescales when you look be­yond the his­tory of the word ‘air­ship’. So be­ware of spe­cial VFR traf­fic south of Bed­ford from the spring.

Air­lan­der Fly­ing in orig­i­nal LEMV form over New Jersey. Why’s she called ‘Mary’? See the mu­tant fe­male char­ac­ter by the same name in the 1990 movie To­tal Re­call

From ahead, the dou­ble hull shape is ap­par­ent, the ‘Mis­sion Mod­ule’ be­ing at­tached be­neath. The nose dock­ing point, yet to be in­stalled, sits just for­ward of the flight deck

As­sem­bling the four en­gines, the dis­tinc­tive ar­ray of thrust-vec­tor­ing but­ter­fly vanes clearly vis­i­ble

Above & right: one of the rear en­gines and the port tailplane be­ing lifted into place early in 2016 at Card­ing­ton

Artist’s im­pres­sion of Air­lan­der 50 in ser­vice

Ma­noeu­vring here at low al­ti­tude, test pi­lot Dave Burns is pitch­ing up while yaw­ing to the right (note the po­si­tion of both the con­ven­tional el­e­va­tor & rud­der sur­faces and the thrust-vec­tor­ing vanes)

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