german vstol

The programmes chief test pilotDrury Wood still considers this atravesty. To him, the Do 31 deservedto end up as a practical operationalaeroplane. It was one product of aperiod when V/STOL seemed to offeranswers to key Cold War NATO needs,with Britain and West Germany at theforefront of developments. Both fearedthe loss of main operating bases forconventional combat aircraft throughWarsaw Pact attacks. If V/STOL jetfighters and strike aircraft were to flyfrom dispersed locations in the field,they would obviously require logisticalsupport. How better to provide this, sothe rationale went, than with a V/STOLtransport?

This was an age of NATO attemptsto come up with common equipmentfor multiple member states. Itinstigated several NATO Basic MilitaryRequirements, a concept of mixedeffectiveness. The first, NBMR-1,dated from 1953; aimed at producinga lightweight tactical strike fighter,selection fell upon the Fiat G91.NBMR-2 followed, its eventualresult the Breguet Atlantic maritimepatroller. With NBMR-3, formallyissued in 1961, V/STOL entered theequation. It was split into two parts,one for a supersonic fighter, the othera subsonic strike platform. NBMR-4was a medium-range V/STOLtransport intended to support both,

BELOW:With DruryWood in the left-hand seat, as he

was for all its ights,Do 31 E3 D-9531

goes throughits paces at

Oberpfaffenhofen.DORNIER

German jet innovation resumed post-war, andin impressive style. The Dornier Do 31 V/STOLtransport was a remarkable achievement wetalked to the test pilot who was instrumental in

this ground-breaking project

VERT ICAL L I F T

hat goes around comesaround. At once the USmilitary is introducingthe Lockheed Martin

F-35B Lightning II, an aircraft witha lift engine for vertical flight, andprocuring the tilt-rotor Bell BoeingV-22 Osprey as its new carrier on-boarddelivery platform. Yet nearly 50 yearsago there flew for the first time a designthat combined attributes of the two.Operating in much the same manneras the F-35B, it could have brought tothe COD role a turn of speed out of theOspreys reach. Sadly, for the DornierDo 31, destined perhaps to remain theworlds only vertical/short take-off andlanding jet transport, it was not to be.

WWORDS: BEN DUNNELL

GermanJETS DORNIER Do 31

AEROPLANE JULY 2015 www.aeroplanemonthly.com 71

later amended to the shorter-rangeNBMR-22.The bureaucratic rigmarole associated

with these latter requirements wasconsiderable. Suffice to say, noneresulted in an agreement on production,let alone a series aircraft. However,technology demonstration prototypeswere another matter. West Germanmanufacturers seized the chance.It may have appeared ambitious for

the Federal Republics first indigenousjet aircraft to be a supersonic V/STOLresearch fighter, but its aeronauticalminds proved equal to the task.The initial prototype of the EWR(Entwicklungsring Sd, or DevelopmentRing South) VJ101C, the X-1, madeits maiden flight in hovering modeon 10 April 1963. Old rivals Heinkeland Messerschmitt had teamed withupstart Blkow to design and build thisrevolutionary machine. Using six Rolls-Royce RB145 turbojets, three each inswivelling wingtip nacelles, an inauguraltransition between jet-borne and wing-borne flight took place that September.It was a major achievement, but morewas to come. By now, Dornier was wellon the way to another West Germanbreakthrough: its V/STOL jet transport.The firm began conceptual studies

back in 1959. Impetus was provided byNBMR-4, for the government in Bonnwished to develop such an aircraft inexperimental form. During February1962 it issued Dornier with a contract.The firm, not long re-establishedin West Germany, was building thesingle-engined Do 27 and twin-enginedDo 28 utility transports. On the Do 31team were many enthusiastic youngengineers with few pre-conceivednotions, this proving a boon.In deciding on a configuration, it

became clear that jet power alone, andthus a true V/STOL capability, wasthe way to go. Some rivals thoughtotherwise. Fiat, for example, cameup with a mixture of Rolls-RoyceDart turboprops and RB162 lift jets

for its G222 (later re-developed as aconventional twin turboprop), but thiswould not have allowed vertical take-offs at higher weights. Nor, Dornierfelt, did anything other than jets affordthe safety margins necessary should anengine fail in a critical phase of flight,such as the transition or a hover.For the Do 31s powerplants, West

Germany again turned to Britain. Inits definitive form, the developmentaircraft was to have 10 in all: twothrust-vectoring Bristol SiddeleyPegasus 5s in under-wing inboardnacelles and eight RB162 lift jets, foureach in wingtip-mounted pods, alsowith vectored thrust. The aim for afuture production model, should it havematerialised, was to carry a maximum8,800lb payload in VTOL mode and13,250lb for STOL operations. Insteadof the Pegasus, its main propulsion wasto be provided by the RB153, a moreadvanced thrust-vectoring turbofanunder development by Rolls-Royce andGerman firm MANTurbo.

Very close collaboration was fosteredbetween Dornier and British industry.In October 1963 it was announcedthat Dornier and Hawker SiddeleyAviation, together with West Germanysdefence ministry and the UKs Ministry

of Aviation, were exploring formal co-operation. HSA had amassed relevantexperience through studies by its deHavilland division for the DH129,designed to meet the NBMR-4requirement. Both companieshave basically the same concept ofpowerplant configuration for such anaircraft, said an HSA statement.

British confirmation of a jointfeasibility study involving the Do 31came in a February 1964 speech byAviation Minister Julian Amery. Thetwo governments, he said, have nowagreed to give the firms the necessarysupport. For HSA, it was intendedto benefit the larger HS681 STOLtransport programme. There were alsojoint plans for military transports underthe DoHS designation.Dornier pressed ahead. The Do 31s

flight control system needed verifying,and to this end two hover rigs wereproduced. The Bodensee-Gertewerkcompany in berlingen built the first,the Reglerversuchsgestell (RVG, literallycontrol testing frame). It was betterknown as the small hover rig. In thehands of German pilot Karl Kssler,this 18m-long device made its first freeflight at Dorniers Oberpfaffenhofenfactory airfield on 21 April 1964.Power was provided by four RB108

lift engines positioned in the 39ft4in (12m)-span transverse member equating to the wing of theun-covered cruciform framework. Itwas controlled in height by varyingthe thrust of the inboard engines, andin yaw by differential swivelling of theoutboard powerplants. Tail-mountedpitch control nozzles were fed from theport and starboard inboard engines.Auto-stabilisation was provided in all

three axes. Basically, these were the samecontrol principles later employed on theDo 31 E3 prototype, and explained inour illustration on page 73.Trials with the RVG were under

way when, in July 1964, the aircrafts(and the Dornier companys) newchief test pilot joined in. Since suitablyexperienced West Germans were in short

Jet power alone, and thus a true V/STOLcapability, was clearly the way to go

ABOVE: This viewof the RVG showsclearly the fourlift engines and, atthe rigs rearmostextremity, the pitchcontrol nozzles.VIA DRURY WOOD

ABOVE LEFT: Athumbs-up fromDruryWood to hisground crew as heprepares for a ightin the RVG, thesmall hover rig. Forhis part in the Do 31programme, theGerman govern-ment awardedWood the Bun-desverdienstkreuzam Bande (FederalOrder of Merit). Healso won 1968sIven C. KincheloeAward for out-standing achieve-ment in test yingfrom the Society ofExperimental TestPilots.VIA DRURY WOOD

ABOVE: The largehover rig in free

ight. DORNIER

ABOVE RIGHT:DruryWood

brought a very widerange of experience

to the Do 31 testprogramme. He was

given the callsignDrache, meaning

dragon.VIA DRURY WOOD

BELOW: The wingtipengine pods of theDo 31 E1, D-9530,

carried weightsrather than lift jets.

AVIATION-IMAGES.COM

supply, the country having only beenpermitted to re-start aviation activities inthe mid-1950s, it was decided to followthe VJ101C programmes example andhire an American.

I had a background that is veryhard for somebody to acquire thesedays, remarks Drury Wood. The ex-USMarine Corps pilot, who flew F4UCorsairs in combat during World WarTwo and the Korean War, then wentto the US Naval Test Pilot School atPatuxent River. Upon graduation, he

returned as one of its instructors. Woodleft the Marines with the rank of Major,though he remained a reservist. Hejoined Douglas as a test pilot, beinginvolved in development of the A3DSkywarrior and A4D Skyhawk amongstothers. Moving to Northrop, he wasengaged in the T-38 Talon programme,

after which he had a stint as a consultanttechnical advisor to the US Army.

A friend of mine named GeorgeBright had previously gone toGermany to fly the VJ101, Drurytold Aeroplane. When they askedGeorge who he would recommendfor the Dornier, I had a reputation bythen in the Navy and the Air Force,they all recommended me, and I wasoff and running. Before long, he andhis family had moved to Bavaria, andDrury was settling in to his new job.

At that time they were just startingwith the small hover rig, he recalls. Iflew that 178 times. This didnt add upto many flying hours, for the RVG onlyhad enough fuel for flights of four-and-a-half minutes each. Most importantly,it worked as advertised. According toDrury, There was a lot of luck, people

told me later, in that we flew a [flightcontrol] system that never failed.Through 1965, all seemed to be going

well. Representatives of the British andWest German aviation and defenceministries met in Bonn during May andrecommended that the collaborativeprogramme be continued. The threeexperimental Do 31 E airframes wereunder construction, the E1 and E3 forflight trials and the E2 as a static testvehicle. In each case, Dornier built onlythe wings; the centre and rear fuselagesections were made by VFW (VereinigteFlugzeugwerke), while HFB (HamburgerFlugzeugbau) supplied the forwardfuselage and the tail unit.Then in November the Anglo-

German collaborative agreement reachedits conclusion, and Britain decided notto renew. A short-sighted decision?Possibly, but bear in mind that theHS681 had earlier been cancelled infavour of an RAF order for LockheedsC-130K Hercules. UK interest inV/STOL transports was on the wane.Now Dornier, albeit supported

financially by the West German

GermanJETS

There was a lot of luck in that we ew aight control system that never failed

DORNIER Do 31

10% (lift engines, 4%)

Hovering ight Conventional ight

The aircrafts two congurations

How the aircraft wascontrolled in the hover

The Do 31 compared with the Fiat G222

Maximum take-off weightsDimensions Capacity

Maximum speed Range

Engines constituted:

The Dornier Do 31 explained

Rolls-Royce Pegasus engines (x2)Similar to those used in the P1127.With nozzles rotated down, theycontributed to the thrust forvertical lift

RB162 lift engines (x8)Four in each wingtip wereswitched on for hovering only

Rolls-Royce Pegasus enginesNozzles rotated rearwards, theyprovided all the thrust for forward ight

RB162 lift enginesSwitched off andcontributed no thrust

YawLift enginenozzles couldbe vectored15 backwardsand forwards

The Pegasussvectoring nozzleswere not used forcontrol in the hover

How the aircraft shaped up against an Italian submission for NBMR-4 that entered service, albeit in developed, non-VTOL, form

Were more or lessidentical but the Do 31sengines accounted for10% of weight comparedto the G222s 4%

PitchAir bleeds from the Pegasus enginespowered small control jets in the tail

RollAchieved by increasingor decreasing thrust oflift engines on one wing,while decreasing orincreasing it on the other(differential control)

Do 31

G222

Do 31 1,120 miles

Do 31 36 troops59.1ft

67.3ft

74.5ft94.2ft

G222 53 troops

Do 31

G222

G222852miles

452mph

336mph

Do 31

60,500lb

4%

G222

61,730lb

Illustration: Ian Bott www.ianbottillustration.co.uk

THE DORNIER Do 31 E3 EXPLAINED


BELOW: Seldomdid the Do 31

demonstrate itsload-carrying

capabilities, butfor the 1968

Hanover show theE1 brought a VWKombi in its hold.DruryWood says,

The Germansnicknamed

the Do 31 theParadepferd, the

parade horse,because we took it

everywhere.AVIATION-IMAGES.COM

ABOVE: A periodmontage of the

Do 31 E3 makingits rst take-off transitionat a snowy

Oberpfaffenhofenon 16 December

1967. VIA DRURY WOOD

government and technically bycontractors including the British enginemanufacturers, had to go it alone. AtOberpfaffenhofen on 30 November1965 it rolled out the Do 31 E1prototype, fitted at this stage with itspair of Pegasus 5s but no RB162s. Infact, despite early plans to the contrary,the E1 never got its lift engines. Thewingtip-mounted pods were instead

filled with equivalent weights to ensurecommonality in flying characteristics.The next step in flight test terms

was the big hover rig, the groesSchwebegestell (SG). This more closelyresembled the Do 31 than had the RVG,though initially it had no empennage,

and the rear fuselage was largely un-covered. The SG expanded the flightenvelope still further, allowing more inthe way of hover stability testing anddevelopment of vertical take-off andlanding techniques. For this it had a pairof Pegasus 5s and six RB162s.Now one of the hazards inherent

in V/STOL flight came to the fore:the problem of hot exhaust gases,

either from lift engines or a thrust-vectoring nozzle, hitting the groundand being re-circulated back into theengine inlets. The result could be atemporary loss of power, or, worse,a serious surge and potential flame-out. With fountains of exhaust gas

being generated by so many engines, theDo 31 was especially prone.Beginning on 20 July 1966, the SG

made 61 flights mounted on a hydraulicpedestal, allowing tests in roll, yaw andpitch. Its first free vertical take-off wasscheduled for 11 January 1967. DruryWood and Franz Rdel, a pilot for militarytest unit Erprobungsstelle 61, were in thecockpit. As Drury recounts, It just sohappened that the nozzles on the Pegasus5 were not exactly calibrated [with theinstrumentation], so as I put the throttlesforward some of the exhaust air hit theground, came up and went into theforward engines. The rig, barely airbornefor a moment, bumped back onto thesnowy concrete. The Germans, Drurysmiles, called it the widerstrebendeDrache, the reluctant dragon.In fact, the cockpit indicator had

shown the nozzles to be vertical whenthey were really pointing slightly forward.Period footage shows the fiery compressorstall that occurred on both Pegasusengines. Thankfully there was no damage.On 24 January, a more controlled, if stilllimited, flight was undertaken.This wasnt the only drama with the

SG. On one flight, says Drury, as I wasgetting ready to make a vertical take-offa bolt came out of a fairing on the right-hand side. That bolt was thrown into thesecond and third engines, and I liftedoff with the engines only roaring on oneside. Fortunately I was able to recover.It required a quick shut-down of the left-hand lift engines to avoid a potentiallydangerous asymmetric situation. Oncemore, no further damage was done. Thiswas the last time any of the powerplantsgave trouble.The big hover rig made just 31 free

flights. Even so, it contributed much.With the SG it was possible to ironout, in a relatively low-risk fashion,snags with on-board systems that couldotherwise disrupt progress with testingthe two Do 31 Es. Most importantly, itunderlined that the flight control conceptworked.The team was now sufficiently well-

prepared to fly the Do 31 E1, and on 10February 1967 it took to the air for thefirst time, again with Drury Wood incommand and Franz Rdel as co-pilot.The sortie was entirely successful, Dornierreporting that it lasted 26 minutes andattained an altitude of 9,000ft.It should have been a matter for

outright celebration, yet joy was temperedby bad news from Bonn. West Germanysnew grand coalition government underChancellor Kurt Georg Kiesinger sought

74 www.aeroplanemonthly.com AEROPLANE JULY 2015

Engines Two Bristol Siddeley Pegasus 5-2s, 13,558lb thrust eachEight Rolls-Royce RB162-4Ds, 4,111lb thrust each

Dimensions Length: 67ft 10in (20.7m)Span: 59ft 3in (18.06m)Height: 27ft 11in (8.53m)

Weights Maximum take-off weight (conventional): 54,013lb (24,500kg)Maximum take-off weight (vertical): 46,297lb (21,000kg)Maximum landing weight (conventional): 48,060lb (21,800kg)Maximum landing weight (vertical): 46,297lb (21,000kg)

Performance Maximum speed: 383kt (441mph, 710km/h) at 8,200ft (2,499m)Maximum cruising speed: 373kt (430mph, 692km/h) at 14,100ft (4,297m)Optimum cruising speed: 291kt (335mph, 540km/h) at 19,680ft (5,998m)

Do 31 E3 at a glance

German

I pulled the Do 31 up and rolled it. A lotof people were worried Id broken it

JETS DORNIER Do 31

to slash its research and developmentbudget, and that very day, 10 February,it confirmed that the Do 31 programmewas among the victims. Dornier wouldbe allowed to complete the test effortfor which funds were already assigned,but no more.At least this permitted the Do 31

E3, lift engines and all, to show what itcould do. Wood and Rdel took it forits maiden flight, another uneventfulaffair, on 14 July 1967. Conventionalflight was the order of the day at first,before moving on to V/STOL work.In the conventional regime, both theE1 and E3 proved docile and pleasantto handle. When I was invited toHawkers to fly the P1127, to get mewarmed up for that they let me fly aHunter, says Drury Wood. That andthe Do 31 had a lot in common theywere comfortable to fly in conventionalflight. Given the Hunters qualities,that comes as praise indeed.Now that two aircraft were flying,

the E3 could concentrate on theV/STOL side while the E1 performedother tasks for which the lift engineswere not necessary. Among these wereflutter trials, measurements of stresson the wings and engine nacelles, andtesting of the aircrafts load-carryingcapability. Time out was taken for adebut appearance in the static park ofthe 1967 Paris Salon. That Septemberthe E1 deployed to the West Germanmilitary research airfield at Manchingfor assessment of the types stallcharacteristics.

By the end of 1967 the E3 hadattained some major milestones. Itssixth flight, on 22 November, beganwith the aircrafts first vertical take-off.A take-off transition from vertical tohorizontal flight was achieved on 16December, and a landing transitionfive days later. Both took place in thesame sortie a verticircuit, to usethe period parlance for the firsttime on 28 February 1968. Hot gas ordebris ingestion problems were all butresolved by selecting a 75-degree angleon the Pegasus nozzles for take-offs, andby the 15-degree tilt of the RB162s.During the E3s test programme, take-off power settings of 70 per cent for allengines were the norm. On landing, therecirculation risk was lessened by nothovering close to the ground.Drury Woods assessment? It was

easy! It was much easier for me thanflying a helicopter, and I had someexperience in those too. Taking off, onehad to memorise when to start the liftengines, but once Id got that routinedown I could do it in my sleep.

I think it would have been an easyaircraft to operate. From cranking upthe lift engines to a conventional flightspeed in excess of the stall took no morethan 20 seconds. Once you got throughthat critical area it was nothing. The liftengines only had an overhaul life of 10


hours, but, my God, you could fly themforever with engine running times of 30seconds or no more than a minute.As far as the auto-stabilisation was

concerned, everything was dandy, butthe landing had to be controlled bythe pilot. We did have an automaticapproach [capability], so you could fly ahands-off approach, but when you cameto hover and landing that had to bedone manually. Once youd committedto a landing, you were committed.April 1968s Hanover show afforded

an opportunity to demonstrate theE3s qualities. I just got tired of doinghigh-speed flybys, says Drury, so Ipulled it up and rolled it. That really setit off. A lot of the German governmentpeople were there, worried that I hadbroken their airplane. Of course theinstrumentation was running, and theairplane doesnt care what attitude its inso long as its doing 1g. We had to proveto the government that no, I had notbroken it. Silvius Dornier, the presidentof the company at that time, said, HerrWood, the government is very anxiousabout this. I am asked to relay to youthat you must never do this again.Then he gave me 5,000 Deutschmarks!Weeks later, at Oberpfaffenhofen

on 27 May, some actual damage wasdone. I made a vertical landing infront of the NATO person in charge oftransport aircraft, and the landing gearfolded up. It was the fault of the Dowtylanding gear an extension rod thatheld them down had gone over-centre,and I just gently settled down onto theairplanes belly. I had the flight engineer

with me, I had the instrumentationrunning, so I was able to plead notguilty and it could be proven. Wejacked it up, Dowty modified thelanding gear, and everything went onas usual.Another British supplier was Martin-

Baker, which provided the flight crewsMk6 ejection seats. The Martin-Bakerseat had the capability of trying torescue one at hovering altitudes andspeeds or lack of speeds butyou would have had to react quickly,says Drury. Nor was it easy to make arapid escape in the event of a ground

ABOVE: Theundercarriageretracts as theDo 31 E3 climbsaway.VIA DRURY WOOD

BELOW: The cockpitof the E3, whichnaturally differedfrom that of theE1 by virtue of theextra controls forthe lift engines.VIA DRURY WOOD

RIGHT: Groundcrewon hand to help

guide the E3 in to itslanding spot. Notethe small windowsin the underside

of the nose, whichassisted the pilot

in locating groundreferences.

VIA DRURY WOOD

emergency. I got into the airplane oneday, turned on the oxygen [] and afire broke out in the cockpit. I managedto escape with the help of one of mycrewmen.As Drury Wood reminds us, I

was the only person who ever satin the left-hand seat and made avertical take-off and landing. Therewas simply no scope to train others.The lift engines had an overhaul lifeof 10 hours and the Pegasus at that

time 50 hours, so there was no timefor indoctrination and training.Nevertheless, a young German test pilotcalled Dieter Thomas, who had flownDo 31 chase sorties in Fiat G91Ts forthe then DVL (Deutsches Versuchs-und Forschungsanstalt fr Luftfahrt,or German Aviation Test and ResearchInstitute), joined the programme inApril 1968. On numerous occasions,Thomas acted as Woods co-pilot. Themost notable entered the record books.It took place in connection with

the E3s visit to the 1969 Paris Salon.Says Drury, I thought, This is astrange airplane for records whydont we just make some?Wecontacted the FAI, and just by flyingfrom Munich to Paris and by beingin such a new category we earned fiveworld records. The ferry flight to LeBourget on 27 May was completed in

one hour 19 minutes and 30 seconds.All five benchmarks for speed overa recognised course, altitude, distance,duration and speed still stand. TheDo 31 was literally in a class of its own.For Dieter Thomas, who later became

Dorniers chief test pilot and flyingdisplay director of the ILA airshow inBerlin, Paris 1969 was an interestingexperience. You must understand,he told the author in 2007, that this10-engined aeroplane was so terriblynoisyWe had to give signals withour thumbs, and I was watching theinstruments while Drury was flying, soI didnt really notice the crowd. Woodhimself says, It was noisy, I must say,just to the point of being damaging.

Even after the German defenceministry made further funds available,resources were still finite, and everytest flight had to count. Sometimesthey were a little out of the ordinary. InMay 1968, Drury remembers, Ling-Temco-Vought came over and laid outa plastic pad in the grass. I think it wasabout 30m square, and I just took offand landed on that with no problems.One other time, for a flight fromOberpfaffenhofen to Hanover, I askedthem to put a Volkswagen bus in [theE1], and they did. That worked quitewell. We just never had the opportunityto test the airplane to its limits.

On the Paris record flight we wereover weight for a vertical take-off withsafety, meaning if we lost a lift engine,and we used the lift engines to shortenthe take-off run. The Pegasus nozzlescould certainly shorten the landing runif one were to make a short landing, butthere we hark back to the first take-offsof the big rig and the Pegasus swallowingits exhaust gases. We did not have thetime to determine the limits of all the


German

Small hover rig 243Large hover rig 31Do 31 E1 101Do 31 E3 154

Do 31 programme:flights completed

ABOVE: Followingtheir record-settingight to Le Bourget,DruryWood and co-pilot Dieter Thomasdemonstrated the

Do 31 E3 at the1969 Paris Salon.On one day theyperformed a co-

ordinated hoveringsequence alongsidea Harrier GR1, both

being Pegasus-powered.

ADRIAN M. BALCH COLLECTION

JETS DORNIER Do 31

take-off and landing possibilities. Atairshows I would fly backwards, butI didnt push it, and in rotating at thehover I never put the rudder pedal to thestop to see how fast I could turn. I did afew stalls, but they were ho-hum, and Inever did Vmax [maximum speed].That said, the Do 31s achievements

remained considerable. In the springof 1969, short take-offs and verticallandings were made at a high weightof 31 tons. There were also trials ofinstrument approaches.Thoughts of military use had gone

out of the window. Instead, attentionfocused on commercial applications,and NASA spent around US$5 millionon a test effort to investigate operationalprocedures for civil V/STOL transports.It took place at Oberpfaffenhofenbetween October 1969 and March1970. We had some successful flightswith NASA, says Drury. They sentsome pilots over and did research onsteep approaches. After all, we couldmake the ultimate steep approach.

The big hover rig was re-activatedas a means of introducing the twopilots from NASAs Ames andLangley Research Centers to theaircraft. They Bob Innis and James

Patton, together with engineers CurtHolzhauser and Sam Morello thenflew with Wood in the Do 31 E3 andliked what they found, except themultiplicity of controls the pilot wasrequired to manipulate for flightpathand airspeed control during thedeceleration to hover, particularlyunder instrument meteorologicalconditions.That, too, was a blind alley. Hopes

for a worldwide boom in civil V/STOLnever came to anything. Dorniers ownDo 131 and Do 231 concepts got littlefurther than artists renderings or scale

models as the market for such aircraftresolutely failed to open up.With that, the Do 31 was almost

done. The E3 made a final Hanovershow appearance in 1970, Wood

joined by co-pilot Friedrich Soos.They returned to Oberpfaffenhofenon 4 May. In Drurys words, The lastflight, coming back from Hanoverwhat a heartbreaker that was. I stillhad some fuel left when I got back,so I circled the field, I circled roundMunich. I looked down at Munich,and I could see the traffic pattern roundthe Marienplatz [a main square in thecity centre]. I thought, Hell, I couldland it right there! But no, there werecars still coming. So, reluctantly I cameback to the airfield and landed there asnormal


We never had the opportunity to testthe airplane to its limits

THE BRITISH VIEWEngineers and pilots from Hawker Siddeley at Dunsfold andthe Royal Aircraft Establishment at Bedford made severalvisits to Oberpfaffenhofen while the small hover rig was undertest. On one occasion, Flt Lt (later Wg Cdr) Clive Rustin of theRAEs Aero Flight accompanied HSAs Bill Bedford and HughMerewether in sampling it.It had no fuel gauge, remembers Clive. As soon as you

started the lift engines, a guy on the ground, Herr Draganow[ight test engineer Radoslav Draganow], would start hisstopwatch. When your ve minutes were up, he waved abig red ag to let you know when it was time to land. Oneday I realised I hadnt yet looked at yaw control, so I put leftrudder on to turn to the left. I went 90 degrees round, andthought, Thats enough Id better go back. I could seeHerr Draganow running back and forth round the perimeter,starting to look as red as his ag, waving it to tell me that mytime was up. I got the message and landed within the veminutes, I might add. The result of that test was that I foundthe yaw control to be very good.

Clive Rustins verdict: I found ying it great fun. It wasvery easy to take off, manoeuvre and land it with precision.A December 1964 RAE report concurred that no majordifculties are foreseen in the control of the Do 31 undernormal, hovering conditions, but expressed concerns abouthot gas and debris ingestion, and said that the dangers ofengine and auto-stabiliser failure raise problems still to beresolved.In return, Dorniers Drury Wood was invited to Dunsfold in

July 1965 to y the P1127 specically, fth example XP980.I must say, it was quite a handful, he says. It was the mostsquirrely airplane I think Ive ever own.On my rst VTOL and transition, I was not yet airborne and

the large re warning light in the middle of the panel lit up.Hugh Merewether was in the tower and I said, Hugh, I havea re warning light. I was doing my best to remain calm Idid not want to crash their airplane. Hugh answered in a verycalm tone, Sorry, Drury, forgot to tell you we have been havingtrouble with that. Not to worry.

ABOVE: Sitting atop the small hover rig are, from left to right,DruryWood, Bill Bedford, HughMerewether and Clive Rustin.The piece of tarpaulin around the cockpit was added to givethe pilot a degree of cold-weather protection!

ABOVE:DruryWood in the cockpit of P1127 XP980 at Dunsfold inJuly 1965. His logbook shows that he ew a Hunter there on 7 July,and the P1127 quite a handful, he says every day thereafteruntil 14 July. VIA DRURY WOOD

ABOVE: Sitting atop the small hover rig are from left to right ABOVE:DruryWood in the cockpit of P1127 XP980 at Dunsfold in

Drury Wood is very straightforwardin his explanation of why theprogramme came to an end. Wejust ran out of money. The onlysupport came from the West Germangovernment, and I must say I wasdisappointed that the UK companiesdidnt jump on the bandwagon and tryto push the Do 31 as much as they didthe Harrier.

I stayed with the company anothertwo years trying to sell the airplaneunsuccessfully here in the UnitedStates. It was pretty lonesome flyingback and forth across the Atlantic, andmostly I was trying to push it to theNavy as a carrier on-board deliverytype. With our range and load wecould beat anything the Navy has had

for COD it would have been awonderful airplane.

I interested the Navy in takingthe airplane to the United States fora tour, and I convinced an Admiralwho had some money [in his budget].They sent a crew over to examine theairplane, which by then had been instorage [at Oberpfaffenhofen] for afew months. They found it totally fitto go, and we were about to bringit over, but unfortunately anotherAdmiral had access to that same potof money and he wanted to put iton a missile. There went that money.Another American company also putin a protest, saying that if the Navywanted this kind of airplane theyshould put it out for a bid.

When I went to Germany this pastDecember for the 100th anniversaryof the Dornier company, one of theengineers told me he had had a visitorfrom the States. They saw the airplanein the museum, and he asked, Whydidnt I know about this before?It is hard to argue with the view

expressed by Dieter Thomas, who diedin 2013, of the Do 31 as a high pointof West German aerospace innovation.Drury Wood, still enthusiastic aboutthe aircraft in his 92nd year, agrees.The Do 31 was successful in everyrespect I can think of, he says. It wasreliable, it was not too difficult to fly, itwas timely. I cant think ofanything except a plain lack ofsupport that stopped it.


German

SEE THE SURVIVORSAfter years as a gate guardian at the Dornier factory aireldat Oberpfaffenhofen, the Do 31 E1 went to the impressivenew Dornier Museum at Friedrichshafen Airport, openedin 2009. It is now displayed outside (picture below left). TheE3, meanwhile, spent a long time outdoors at the DeutschesMuseum in central Munich. When the museum opened itsFlugwerft Schleissheim facility at Oberschleissheim aireld,

north of the city, in the mid-1990s it was restored and movedthere. Today it is under cover (picture below right), andpositioned next to another German V/STOL research aircraft,the VFW-Fokker VAK 191B strike jet.

For more information, visit www.dorniermuseum.de andwww.deutsches-museum.de/ugwerft/information

DANIJEL JOVANOVIC/AIRTEAMIMAGES.COM JOHN DUNNELL

RIGHT: Fromleft to right, the

Do 31 E3, the largehover rig and the

Do 31 E1 lined up atOberpfaffenhofen,

joined by theproject team.VIA DRURY WOOD

RIGHT: From

JETS DORNIER Do 31

ACKNOWLEDGEMENTS:Special thanks to Drury

Wood for his veryconsiderable assistance.The late Dieter Thomasprovided data from apresentation he andight test engineersDietrich Meyer andProf Dr Hans Rick

gave to a DeutscheGesellschaft fr Luft-

und Raumfahrtsymposium in 2000,

as also publishedin Die deutschenSenkrechtstart-

Flugzeuge(DGLR, 2000).

german vstol

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