Flight test: Black­burn B2

Op­er­ated from Old War­den, BAE Sys­tems Her­itage Flight’s B2 is the only re­main­ing ex­am­ple of Black­burn’s un­usual side-by­side trainer, the launch pad for many an RAF pi­lot’s fly­ing ca­reer

Pilot - - CONTENTS - Words: Dave Un­win Pho­tos: Dar­ren Har­bar

This sole sur­viv­ing ex­am­ple of the early-30s side-by-side trainer looks beau­ti­ful but is slow and its top wing blocks the view

As I walk out across Old War­den’s hal­lowed turf to the shin­ing sil­ver bi­plane wait­ing pa­tiently on the greensward it oc­curs to me that even a ca­sual ob­server might think that the B2 looks a lit­tle bit dif­fer­ent, although they might not know why. Although an open cock­pit bi­plane of 1930s vintage is not an un­usual sight at Old War­den, as it is home to the famed and fab­u­lous Shut­tle­worth Col­lec­tion, two anom­alies are im­me­di­ately ap­par­ent−the fuse­lage is made of me­tal, and the seats are side-by-side!

De­signed by the Brough-based Black­burn Aero­plane and Motor Com­pany Ltd, the B2 was based on an­other Black­burn de­sign; the Gipsy Iii-pow­ered Blue­bird IV. It re­tained the ba­sic lay­out, side-by­side seat­ing, and fab­ric-cov­ered wings of the ear­lier ma­chine, but in­stead of the Blue­bird’s ‘rag and tube’ fuse­lage the B2 has a stressed-skin me­tal struc­ture.

The pro­to­type was pow­ered by a 120hp Gipsy III and made its maiden flight from Brough on 10 De­cem­ber 1931. Owned ini­tially by com­pany chair­man Robert Black­burn as a re­place­ment for his per­sonal Blue­bird IV, it made its pub­lic de­but at the SBAC show at Hen­don the fol­low­ing year.

Black­burn only made 42 B2s and the test air­craft, G-AEBJ was the 37th made, and is the only one still in ex­is­tence. Black­burn be­came part of Hawker Sid­de­ley Avi­a­tion, then Bri­tish Aerospace, and ul­ti­mately BAE Sys­tems.

The B2 is now op­er­ated as part of BAE’S Her­itage Flight, based mostly at Old War­den, which is where I meet it and BAE Sys­tems’ test pi­lot (and Her­itage Flight pi­lot) Peter Koso­gorin on a glo­ri­ous May morn­ing. It’s the day be­fore Shut­tle­worth’s sea­son pre­mier and, as the BAE Sys­tems’ Her­itage Flight will be fly­ing sev­eral air­craft in the dis­play, Pete is a very busy guy. While he goes fly­ing in the Flight’s re­cently re­painted Avro An­son, I take the op­por­tu­nity to make an un­hur­ried in­spec­tion of the Black­burn.

Like many light air­craft of the 1930s, early B2s were pow­ered by a Cir­rusHer­mes IVA en­gine of 120hp, but ‘Bravo Juliet’ has a 130hp DH Gipsy Ma­jor 1F. This air-

cooled, in­verted four-cylin­der en­gine turns a wooden fixed pitch pro­pel­ler and, as the Gipsy is a ‘left-hand trac­tor’, the air in­let at the front of the cowl­ing is on the left side of the nose bowl, en­sur­ing that the cool­ing air flows from left to right across the cylin­ders. The ex­haust stubs are short and−i soon dis­cover−make the en­gine quite loud.

Ac­cess is good as the side pan­els of the pol­ished alu­minium cowl­ing hinge open eas­ily on both sides, while the ducts just aft of the cowl­ing (for eject­ing hot air from the en­gine bay) are prac­ti­cally a work of art. A flat, eleven-litre oil tank is fit­ted be­low the en­gine bear­ers, di­rectly be­low the motor. It’s good prac­tice to check the oil as reg­u­larly as the fuel, as us­ing nearly three litres an hour is con­sid­ered ac­cept­able.

The fuel is car­ried in the cen­tre sec­tion, which is es­sen­tially an aero­foil-shaped 100-litre tank. An op­tional ex­tra for long-dis­tance flights was an aux­il­iary tank mounted in the cock­pit in place of the pas­sen­ger seat, which was

fit­ted with a small hand pump to move the fuel up to the main tank, from where it was grav­ity fed to the en­gine. Other op­tions in­cluded ‘wire­less ap­pa­ra­tus’ (with a winch for the aerial on the right side of the cock­pit), re­con­nais­sance cam­era, cam­era-gun, an ‘Aldis’ sight, and even the abil­ity to carry four twenty-pound bombs (in pairs un­der each lower wing).

The fuse­lage is a ‘semi­mono­cocque’ de­sign (un­usual− and ad­vanced−for the early 1930s) and fea­tures a struc­ture of hol­low me­tal frames which are re­in­forced by stringers and braced hor­i­zon­tally by di­ag­o­nal steel tubes. The stressed cov­er­ing of riv­eted Al­clad sheets is re­in­forced by three pro­nounced lon­gi­tu­di­nal stiff­en­ers. The cen­tre-sec­tion is car­ried by six struts (two ver­ti­cal and the other four as two in­verted Vs, by the rear spar) while the wings are of the sin­gle-bay type, fea­ture steel spars and ribs, and have equal span and chord.

In com­mon with many light air­craft of the era the wings can be folded quickly for easy stor­age

(they pivot around hinges on the rear spar), re­duc­ing the over­all span from over nine me­tres to lit­tle more than three. A lovely pe­riod touch is that the wing-fold pins are held in by small leather straps. Only the lower wings carry Frise-type ailerons, while the up­per wings fea­ture (ac­cord­ing to a de­light­ful plaque in the cock­pit) a ‘slot­ted wing made un­der Han­d­ley Page patents’.

The wide-track di­vided un­der­car­riage fea­tures tele­scopic front legs with steel springs and oil dash­pots, the in­ner ends of each curved axle be­ing hinged to the cen­tre­line be­neath the fuse­lage. Dun­lop ‘Air­wheels’ were stan­dard (floats were an op­tion) and Bravo Juliet still has the orig­i­nal ‘Air­wheels’ hub­caps. The coil-spring tail­skid doesn’t steer but piv­ots in trail through ap­prox­i­mately 150 de­grees.

The tailplane is rigidly braced by four struts. Tailplane, fin and rud­der are of sim­i­lar con­struc­tion to the wings, although here the spars are of tubu­lar sec­tion and the ribs made of Du­ra­lu­min. The tailplane’s in­ci­dence can be ad­justed, but only on the ground. Even by the stan­dards of the time the fin seems tiny while, con­versely, the rud­der is huge. All the fly­ing sur­faces are fab­ric cov­ered.

While wait­ing for Pete, I lis­ten in as BAE Sys­tems’ pi­lot John Hur­rell briefs fel­low Her­itage Flight pi­lot Damien D’lima on the B2’s idio­syn­cra­sies and foibles. Time very well spent, as John’s brief­ing is ex­cel­lent. I then watch John and Damien shoot some touch-and-goes which re­veal that, although the B2 takes off quite quickly, it seems some­what re­luc­tant to climb.

The An­son and B2 re­turn at about the same time and Pete in­di­cates it’s my turn. While he grabs a bot­tle of wa­ter I strap my­self in. There are well-pro­por­tioned wing root walk­ways on both sides, while the fold-down doors are like a Tiger Moth’s. As the in­verted-v struts that sup­port the cen­tre sec­tion are at­tached to the rear spar aft of the cock­pit, ac­cess is quite good. The seats ad­just

The panel is dom­i­nated by a huge turn and slip

ver­ti­cally via a rather el­e­gant sys­tem. There is a lever out­board of each seat topped with two large han­dles, which you squeeze to­gether to un­lock a ratchet and then raise and lower the seat. The ped­als can also be ad­justed, al­beit not eas­ily. Con­sid­er­ably less sat­is­fac­tory is the gen­uine Sut­ton har­ness. This is a ghastly con­trivance of straps with mul­ti­ple holes and pins, which is al­most im­pos­si­ble to get tight and com­fort­able. How Hur­ri­cane and Spit­fire pi­lots man­aged I re­ally don’t know.

The panel is typ­i­cally 1930s, be­ing a col­lec­tion of black-faced di­als in a black-painted board and bereft of any colour-cod­ing or even min/max in­dices for speed, rpm or pres­sure. It is dom­i­nated by a huge, cen­tral­ly­mounted Reid and Si­grist turn and slip in­di­ca­tor, pow­ered by a ven­turi tube on a strut near the cock­pit. Left of the turn and slip is an ASI also com­mon to many types of the time, and some­what am­bi­tious as it goes up to 280kt (with the poin­ter trav­el­ling through about 640 de­grees in the process). This has two sig­nif­i­cant dis­ad­van­tages: first, more than two-thirds of it is com­pletely re­dun­dant; and sec­ond− and more per­ti­nently− the scale ex­pan­sion at low speed is poor.

Right of the T&S is a fore-and-aft cli­nome­ter, and then a sin­gle-poin­ter al­time­ter (it’s not a ‘sen­si­tive al­time­ter’, as it doesn’t have a Kolls­man win­dow). A large tachome­ter be­neath the ASI, an oil pres­sure gauge be­low the cli­nome­ter, and a P11 ape­ri­odic mag­netic com­pass com­plete the set. The oil tem­per­a­ture gauge is no­table by its ab­sence. As oil tem­per­a­ture and pres­sure are quite closely re­lated, and this re­la­tion­ship is an ex­cel­lent in­di­ca­tor of an en­gine’s health, this seems to me to be a cu­ri­ous omis­sion.

Be­tween the com­pass and T&S is the red-painted fuel shut­off valve− which re­minds me that I haven’t yet lo­cated the fuel gauge. Af­ter cast­ing about un­suc­cess­fully I look up and find it mounted in the cen­tre sec­tion, al­most di­rectly above the cock­pit. Cur­rently la­belled ‘inop’ it is cal­i­brated in im­pe­rial gal­lons, with the last four in red. This, as a plac­ard on the panel use­fully points out, means ‘only 1/2 hours petrol sup­ply re­mains’. Good to know!

The panel also has two gen­er­ously-sized glove­boxes for− pre­sum­ably −gen­er­ously -sized gloves. Beau­ti­fully-made leather map pock­ets adorn each cock­pit side­wall.

Each pi­lot has their own throt­tle and mix­ture con­trols; one pair of levers is cen­trally mounted and the other is on the left cock­pit wall. The yel­low mix­ture levers are wire-locked ‘rich.’ In be­tween the seats is a lever for pitch trim, which ad­justs the trim bias via ten­sion on springs in the el­e­va­tor cir­cuit. I have read that the rud­der can also be trimmed but couldn’t see how!

Once Pete is strapped down with the di­abol­i­cal Sut­ton Har­ness we’re ready to start. The

Gipsy, how­ever, by now nei­ther hot nor cold, is con­se­quently capri­cious, but af­ter some suck­ing in (of fuel and breath) and blow­ing out (of en­gine and cheeks) Shut­tle­worth stal­wart Rory Cook gets it go­ing. Af­ter the tra­di­tional four-minute wait for the motor to warm up, the ev­er­a­menable Rory drapes him­self across the rear fuse­lage, the en­gine is run up, mags checked and it’s ‘chocks away’.

A touch more throt­tle gets the Gipsy growl­ing and we set off to­wards the run­way. Of course the B2 has no brakes, and if you’re won­der­ing how you taxi it the short an­swer is “care­fully”. The slightly longer an­swer is “care­fully, and it de­pends on the wind”. To­day the wind is very light and I’m quite con­fi­dent that I can get us to the run­way un­aided. In a wind of any (and I do mean any) strength, ask for a wing-walker at the start, be­cause sooner or later (and prob­a­bly sooner) you’ll need their as­sis­tance. The field of view while taxy­ing is (for an air­craft of this vintage) quite good.

Pre-take­off checks are as min­i­mal as you’d ex­pect. Am­bi­ent con­di­tions are a ‘light and vari­able’ wind with an OAT of 20˚C. Pete makes the first take­off while I fol­low through. Hav­ing aligned the air­craft with the cen­tre of the run­way Pete rolls for­ward a few me­tres to en­sure the tail­skid is straight and then slowly opens the throt­tle. There’s no dif­fi­culty keep­ing straight and that huge rud­der soon starts to bite. Ac­cel­er­a­tion is ad­e­quate but not out­stand­ing, although it is quite a warm day. The grass is short and dry and I’d guess we use about a third of the 500m run­way be­fore climb­ing away at what felt like about 600fpm (there’s no VSI, and the al­time­ter is pretty vague) and 65kt. We fol­low the cam­era­ship Chip­munk (flown by Bob Mor­com and car­ry­ing pho­tog­ra­pher Dar­ren Har­bar) out to the east.

As soon as the pho­tos are in the can, Pete passes con­trol to me and I be­gin to eval­u­ate the gen­eral char­ac­ter­is­tics. Start­ing with a few turns of vary­ing de­grees of steep­ness and a few re­ver­sals, my ini­tial im­pres­sions are that the con­trols are quite smooth and rea­son­ably light, the break­out forces ac­cept­able and the ra­tio of stick force to speed sat­is­fac­tory. I’m not quite so sure about the con­trol har­mony, as the ailerons seem heav­ier than the el­e­va­tor, although not un­pleas­antly so. Quite cor­rectly, the rud­der is the heav­i­est, although it’s not that heavy. As an­tic­i­pated, there’s lots of ad­verse yaw and any mis­han­dling (or should that be mis­footling?) of the rud­der is clearly in­di­cated by the T&S’s judge­men­tal poin­ter and a blast of air around the wind­shield. The stick-free sta­bil­ity seems to be slightly

pos­i­tive in pitch, just barely pos­i­tive in roll and dis­tinctly neg­a­tive in yaw (but then the fin re­ally is small). I also sus­pect that the dom­i­nant rud­der could pos­si­bly over­power the ailerons if mis­han­dled. It’s prob­a­bly not a lot of fun to fly on gusty, tur­bu­lent days, like most air­craft from this era.

Now I’m fly­ing it I’m much more aware of the blind spot di­rectly above the cock­pit. Over­all, the field of view for an air­craft of this vintage isn’t bad, but look­ing straight up it’s rather in­ad­e­quate. And of course, as the pi­lot and in­struc­tor are sit­ting side-by-side they both have the same blind spot.

Be­fore even think­ing about land­ing I al­ways like to know what the han­dling is like at the slow end of the speed spec­trum, so I do a clear­ing turn fol­lowed by a cou­ple of stalls. These pro­duce no real sur­prises. If the stall is ap­proached slowly the B2 never re­ally stalls, but just ‘mushes’ with the sink rate in­creas­ing. Get the nose a lit­tle bit higher and de­cel­er­ate quicker and it does even­tu­ally drop its nose, but in a very half-hearted fash­ion, at around 38kt (as I said, the ASI

I throt­tle back and we float along par­al­lel to the run­way

scale ex­pan­sion at slow speed re­ally is very poor). As the stall is ap­proached the Han­d­ley Page slots chat­ter slightly as they ex­tend.

Pete now takes con­trol to demon­strate a loop. The prop is quite fine for a Gipsy Ma­jor 1F and care must be taken not to over-speed the en­gine. As we go over the apex of the loop I tilt my head back to look for the hori­zon and get a fine view of the up­per wing and lit­tle else. The field of view up­ward re­ally is most un­sat­is­fac­tory.

For the brief tran­sit back we cruise at a com­fort­able 2,050rpm, which gives a sur­pris­ingly slow 65kt IAS for a fuel flow of ap­prox­i­mately 30 lit/hr. I thought the B2 would be slow but not this slow−and won­der if the tachome­ter is pos­si­bly over­read­ing. (Back on the ground Pete ex­presses the same opin­ion; in­ves­ti­ga­tion is on­go­ing.)

As we ap­proach Old War­den we can see that John Hur­rell is con­duct­ing a dis­play prac­tice in the An­son, so I throt­tle back and we float along par­al­lel to the run­way and a few miles to the east at a lazy 55kt. This is an un­ex­pected bonus as it gives me the op­por­tu­nity sim­ply to savour the flavour and char­ac­ter of the B2. The air is warm and soft, and the cock­pit cosy. The en­gine is ruf­fling un­hur­riedly (but still nois­ily!) to it­self and the vista spec­tac­u­lar. The oil seed rape fields are glow­ing gold in the strong sun­light, the mon­u­men­tal air­ship sheds at Card­ing­ton look like aero­nau­ti­cal cathe­drals, and the An­son swoop­ing re­gally above Old War­den gives the scene a slightly un­real air. Is it 2018, or 1938? It re­ally is just won­der­ful. Ev­ery avi­a­tor should get the op­por­tu­nity to view the patch­work quilt of the English coun­try­side framed be­tween the wings of a bi­plane at least once, and to do so in the much more so­cia­ble set­ting of a side-by-side cock­pit makes the whole ex­pe­ri­ence even more agree­able.

Dis­play prac­tice com­plete, the An­son turns down­wind and I fol­low at a rea­son­able dis­tance and about 65kt. The wind is es­sen­tially the same as when we left, which means we’re land­ing up­hill on R21. Abeam the num­bers I slowly ease the throt­tle back and com­mence

I've never seen 130 horses work so hard and achieve so lit­tle

A mem­o­rable flight

air­craft on a beau­ti­ful day, but let’s just take these rose-tinted gog­gles off for a mo­ment. I’d be re­miss in my du­ties if I failed to point out that I’ve never seen 130 horses work so hard and achieve so lit­tle, while the up­ward field of view is dis­tinctly un­sat­is­fac­tory (as I’ve al­ready said). Fi­nally, the so-so ailerons, tiny fin and gi­ant rud­der prob­a­bly make it a bit of a hand­ful on gusty days (although that ob­ser­va­tion holds true of most 1930s bi­planes).

But what a joy − and what a priv­i­lege − to fly such a unique ma­chine from an equally unique air­field. BAE Sys­tems are to be com­mended for con­tin­u­ing the His­toric Flight, and I’d very much like to thank both the com­pany and Peter Koso­gorin for giv­ing me this won­der­ful op­por­tu­nity. I just hope you enjoyed read­ing about the B2 as much as I enjoyed fly­ing it! Taxy­ing back in I can al­most hear the click of the myr­iad cam­era shut­ters, even above the rau­cous bark of the stub ex­hausts. It’s been a mem­o­rable flight in a mem­o­rable a curved ap­proach while bleed­ing the speed off to sixty, pulling the trim al­most all the way aft, and sit­ting up a lit­tle straighter in my seat. I and, to an even greater ex­tent, the B2’s cus­to­dian at that mo­ment Pete, face an in­ter­est­ing di­chotomy.

I hope read­ers will not take it amiss when I say that there was a rea­son­able amount of ex­pe­ri­ence in the cock­pit that day. Pete’s CV is im­pres­sive (he’s an ex­per­i­men­tal test pi­lot on the Ty­phoon and F-35) and I have a bit of time in sev­eral dif­fer­ent types. So, where’s the di­chotomy? Well, on one hand the B2 is an el­e­men­tary trainer, and on a day like to­day (al­most no wind, land­ing on grass and up­hill) I could prob­a­bly al­most land it in my sleep. But on the other hand it is a unique air­craft. It’s not just the only air­wor­thy one in the world, it’s the only one in the world! I must do ev­ery­thing right, as I’m sure Pete will in­ter­vene early if any­thing is even slightly less than per­fect.

As we come ‘around the cor­ner’ the B2 feels nicely speed-sta­ble, and by fly­ing a curved con­stan­ta­spect ap­proach with just a sug­ges­tion of throt­tle it is easy to judge when to roll the wings level while si­mul­ta­ne­ously draw­ing off the last bit of power. On short fi­nal I’m slightly high but a small side-slip sorts it. Over the hedge at 55kt and, af­ter a fleet­ing, float­ing mo­ment, the B2 set­tles gen­tly onto the ground, the tail­skid rasp­ing through the grass as the weight trans­fers seam­lessly from the wings to the wheels in a per­fect three-poin­ter; nice. Care­fully open the throt­tle, a quick glance in­side to check that the rpm is greater than 2,000, pick up the tail­skid, pause, a hint of back­pres­sure on the stick, and the B2 waf­fles back into the air. Wait for it to ac­cel­er­ate to 65 and then (and only then!) climb away. Magic. I could− hon­estly− hap­pily do this all day, but Pete is very busy, so (with con­sid­er­able re­luc­tance on my part) af­ter two more land­ings we taxi back to the pumps.

With oil con­sump­tion of up to three litres per hour be­ing con­sid­ered ac­cept­able, top­ping up the tank is a rou­tine re­quire­ment

ABOVE: Dave lends scale to what is a com­pact air­craftRIGHT: an ‘art deco’ look you might nor­mally as­so­ciate with US sports air­craft of the era BE­LOW: power comes from a Gipsy Ma­jor 1F

CLOCK­WISE FROM TOP LEFT: nicely en­gi­neered slat hinge links and swiv­el­ling, coil-sprung tail­skid; and a pro­pel­ler suited to ei­ther the Cir­rus-her­mes IV or DH Gipsy Ma­jor en­gine fit­ted to the B2

ABOVE: jury strut ex­tends for wing fold­ing, although to judge from... BE­LOW: ... the pin se­cur­ing straps, it’s not often done to­day!

ABOVE: panel is dom­i­nated by the cen­tral turn and slip, and P11 com­passABOVE RIGHT: com­mon to­day, side-by-side seat­ing was un­usual for a 1930s trainerLEFT: small fins and big rud­ders (es­sen­tial in tam­ing way­ward tail­drag­gers) were typ­i­cal of the B2’s era

LEFT: act­ing as a sunshade here, the top wing blocks a sig­nif­i­cant part of the view when fly­ing aer­o­bat­icsBE­LOW: rolling ma­noeu­vres ben­e­fit from proper use of the pow­er­ful rud­der

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