Flight Test: Avro An­son/19

One of the few re­main­ing air­wor­thy An­sons/type XIXS of 11,000 built, this solid, sin­gle-pi­lot air­craft ben­e­fits from two crew oper­a­tion and a gen­tle touch

Pilot - - CONTENTS - Words: Dave Un­win

De­vel­oped from an air­liner into a light bomber, the An­son served as an RAF trainer... and then be­came an air­liner again

Old War­den’s sun­scorched strip looks some­what short af­ter Farn­bor­ough’s enor­mous run­way, but I’m not stressed be­cause I’m not do­ing the land­ing. There’s prac­ti­cally no wind and in the left seat Pete Koso­gorin has the only brake lever on his yoke, so we’ve de­cided that, to avoid pos­si­bly scar­ing both of us, I’ll fly the ap­proach down to about fifty feet. When it’s ap­par­ent whether it would have worked (or not!) I’ll take the An­son around and he will then land it. Con­se­quently, I’m very re­laxed about the whole thing, and the com­bi­na­tion of calm con­di­tions, ex­cel­lent coach­ing and a sta­ble air­craft pro­duce a very steady ap­proach. Vref is sev­enty knots and, as we cross the hedge, the an­gle to the thresh­old, speed and sink rate are all per­fect. As good land­ings come from good ap­proaches, I’m pretty sure a good land­ing would’ve been the re­sult. “OK Dave, go around.”

Aware of the propen­sity of Bri­tish in­ter-war ra­di­als to suf­fer from a ‘rich cut’ if the power is in­creased too quickly, I add just enough to ar­rest the sink rate, pause while each en­gine’s rpm sta­bilises, and then slowly and pro­gres­sively open the throt­tles while Pete re­tracts the un­der­car­riage and then milks up the flaps. Even with our for­ward cen­tre of grav­ity the nose wants to rise, and I quickly wind on some nose down trim. As I turn the An­son back onto the down­wind leg Pete looks across at me and grins. “Very nice− lovely and smooth. In fact, that was such a sta­ble ap­proach that you may as well land it off the next one.” Sud­denly I’m not quite so re­laxed, but more ex­cited than ner­vous. What a priv­i­lege!

The Avro An­son is one of those air­craft that re­ally is an un­sung hero. It may not have the bravado of a Beau­fighter, the machismo of a Mos­quito, or the iconic sta­tus of its im­mor­tal sta­ble­mate the Lan­caster, but the old ‘An­nie’ per­formed ster­ling ser­vice in myr­iad roles with the RAF from 1936 to 1968, along with many other air forces and civil­ian op­er­a­tors. Some were still earn­ing their keep well into the 1970s. It was even used as a multi-en­gine trainer for pi­lots con­vert­ing on to the Me­teor jet fighter!

And the num­bers speak for them­selves. De­signed by the great Roy Chad­wick, the An­son was one of the most suc­cess­ful air­craft ever pro­duced by A V Roe and Co, over 11,000 be­ing built in Eng­land and Canada. De­signed to

The Avro An­son is one of those air­craft that re­ally is an un­sung hero

meet an Air Min­istry spec­i­fi­ca­tion for a rel­a­tively cheap coastal re­con­nais­sance ma­chine, Avro took its six-seat 652 air­liner as the ba­sis for its ten­der, and the pro­to­type made its maiden flight from Wood­ford on 24 March 1935. It beat the com­pet­ing DH.89. The Min­istry of Sup­ply placed an ini­tial or­der for 174 and the type−now named An­son af­ter the fa­mous Bri­tish Ad­mi­ral Ge­orge An­son−re­mained in con­tin­u­ous pro­duc­tion un­til 1952. Al­though there are quite a few in mu­se­ums, air­wor­thy An­sons are rather rare, in­clud­ing the sub­ject of this flight test, G-AHKX.

At this junc­ture, and be­fore some of our more ea­gle-eyed read­ers start reach­ing for their quills, I should point out that, al­though we even use ‘An­son’ as our call­sign, strictly speak­ing, it isn’t.

Kilo X-ray is ac­tu­ally an Avro 652A Type XIX Se­ries 2, and was built in 1946 in Avro’s fac­tory at Yeadon (now Leeds Brad­ford) as the Se­ries 2 pro­to­type. It flew with Smiths Air­craft In­stru­ments un­til 1960 and, af­ter a long and che­quered ca­reer, fin­ished up at the Strathal­lan Col­lec­tion in 1974. It has been owned by the BAE Sys­tems Her­itage Flight since it left the Strathal­lan Col­lec­tion in 1981, and has been based at Old War­den with the world-fa­mous Shut­tle­worth col­lec­tion since 2002. It’s been on dis­play dur­ing

Pete tells me that, when taxy­ing, the big tailplane wob­bles

the Farn­bor­ough air­show and now needs to be re­turned home on the evening of the last day. Would I be in­ter­ested in be­ing its co-pi­lot? What do you think?

BAE Sys­tems Her­itage Flight pi­lot Peter Koso­gorin will be my men­tor and cap­tain. As he is on the air­show’s fly­ing com­mit­tee, we’re not go­ing any­where un­til the show ends, so I hang out at the An­son with BAE Sys­tems Her­itage Flight Di­rec­tor Howard Ma­son and Hawk Chief En­gi­neer Graeme Cod­ner and take the time for a lan­guid pre­flight. Three items im­me­di­ately catch the eye. The tailplane is huge (it’s ac­tu­ally larger than my Jodel D.9’s wing­span), there aren’t any cowl flaps, and the un­der­car­riage seems to use sec­tions of Armco bar­rier for the rear brac­ing strut. The empty weight is an im­pres­sive three tons, and I’m start­ing to see why.

The fuse­lage is a steel-tube struc­ture that’s mostly fab­ric­cov­ered ex­cept for the nose sec­tion, which uses ply­wood. Un­like ear­lier mod­els which had a wooden wing, the Type XIX (some­times also re­ferred to as an Avro Nine­teen) is all-me­tal, its can­tilever two-spar main­plane be­ing built in five pieces. The in­ter­change­able outer sec­tions are fit­ted with Frise ailerons and de­tach­able wingtips, while the cen­tre-sec­tion car­ries the main un­der­car­riage and large split flaps (both hy­drauli­cally-ac­tu­ated) and a pair of Arm­strong Sid­de­ley Chee­tah ra­di­als. Each of th­ese has a pair of 159 litre fuel tanks lo­cated out­board of the na­celles.

The Chee­tah is an in­ter­est­ing en­gine. De­rived from the Lynx (early Chee­tahs were known as Lynx Ma­jors) it is a su­per­charged seven-cylin­der air-cooled ra­dial that was pro­duced in sev­eral dif­fer­ent vari­ants be­tween 1935 and 1948, rang­ing in power from 230 to 420hp. Kilo X-ray’s en­gines are Chee­tah XVIIS, which pro­duce 385hp each at +4 boost and 2,550rpm, and are fit­ted with Dowty-ro­tol me­tal two-blade con­stant-speed pro­pel­lers but, cu­ri­ously, no cowl flaps. The main wheels re­tract into the en­gine na­celles and are fit­ted with pneu­matic drum brakes. In­ter­est­ingly (and in com­mon with some other de­signs of this era), even when re­tracted about half of each wheel still protrudes, and in the event of a wheels-up land­ing the brakes will still work!

The very big tailplane car­ries a huge el­e­va­tor and the fin a large, mass-bal­anced rud­der. Pete later told me that, when taxy­ing, the tailplane wob­bles in a most dis­con­cert­ing man­ner! With the ex­cep­tion of the flaps all the fly­ing con­trol sur­faces and their as­so­ci­ated trim tabs (the el­e­va­tor has two) are fab­ric-cov­ered. Of par­tic­u­lar in­ter­est (to me at least) is that the cas­tor­ing tail­wheel doesn’t lock.

The show ends, Pete turns up and promptly changes into an old fly­ing suit. “Get­ting into char­ac­ter, eh?” I ob­serve. Pete grins good na­turedly but he has the last laugh. As al­ways with a ra­dial the first thing to do is to pull each en­gine through sev­eral blades (to avoid hy­draulic lock), and when we’ve done that ven­ture into the wheel-wells to open the oil shut-off valves. My shirt pays the price.

Both the emer­gency hy­draulic pump and primer are be­hind the P1's seat

Ac­cess to the cabin (which can carry up to six peo­ple, al­though our only pas­sen­ger to­day is Graeme) is via a door on the port side, just aft of the wing. Hav­ing stepped over the mainspar, I sit down in the co-pi­lot’s seat and take stock. I’d as­sumed that a Bri­tish twin en­gine air­craft de­signed in the thir­ties would be an er­gonomic night­mare, and I’m not dis­ap­pointed.

Al­though of­ten op­er­ated as a two-crew cock­pit, it’s de­signed to be flown sin­gle pi­lot, with the flight in­stru­ments on the port side and the en­gine gauges in two columns of three in a sub­panel an­gled slightly to­wards the P1. Th­ese in­di­cate (from top to bot­tom) cylin­der head tem­per­a­tures, rpm (there’s even a rudi­men­tary syn­chro­niser in the tachome­ter), boost, oil tem­per­a­ture and pres­sure. Other di­als, scat­tered seem­ingly at ran­dom around the panel, show fuel quan­tity and pres­sure, volts, suc­tion and flap po­si­tion. I never did find the hy­draulic pres­sure in­di­ca­tor, while the brake triple pres­sure gauge (it has three point­ers, one for each wheel brake and one for the main ac­cu­mu­la­tor) is hid­den be­hind the left-hand con­trol col­umn.

A cen­tre con­sole car­ries the twin throt­tles, with the prop levers be­low the throt­tles, the el­e­va­tor trim on the right and levers for ‘Air Cleaner’ and ‘Air In­take Heat’ on the left. Mix­ture con­trol is au­to­matic. The un­der­car­riage se­lec­tor is a large plunger in front of the rud­der trim knob near P1’s right knee, while the flap se­lec­tor is a yel­low T-han­dle by P1’s left hip. The large yel­low lever for the emer­gency hy­draulic pump, and a big Ki-gass primer are both lo­cated be­hind the P1 seat, while the two fuel cocks are also un­reach­able from the P1 po­si­tion, be­ing on the star­board side of the cock­pit. Fi­nally, the starter, ig­ni­tion boost and feath­er­ing but­tons are di­rectly in front of the pi­lot, with the de­light­ful brass mag­neto switches (which wouldn’t have looked out of place in a Vic­to­rian house) above the wind­screen.

As with any multi-en­gine ra­dial, start­ing is part pro­ce­dural and part rit­ual, for if a mo­tor is re­cal­ci­trant, in­vo­ca­tions are not un­usual, curses are com­mon and prayers may even be of­fered! Even­tu­ally the myr­iad but­tons, han­dles, knobs, levers, plungers and switches are pulled, pushed, set, turned or twisted−and we’re ready to fire up.

Al­though the An­son was de­signed for sin­gle pi­lot op­er­a­tions, Pete and I are go­ing to op­er­ate it as a crew. In­deed, sim­ply start­ing it by your­self would not be easy. While Pete presses the port en­gine’s starter and ig­ni­tion boost but­tons with the fin­gers of one hand and guards the throt­tle with the other, I’m equally busy with the primer (which, you may re­call, is be­hind his seat) and the mags (which are only turned on af­ter the en­gine fires). The star­board mo­tor seems in­clined to­wards an­other cou­ple of squirts of primer to keep it run­ning and smoke sput­ters from the ex­haust un­til sud­denly the re­main­ing cylin­ders catch, the pro­pel­ler blades morph into a sin­gle shim­mer­ing cir­cle and the Chee­tah set­tles into a lazy growl.

Pete’s a no-non­sense BAE Sys­tems test pi­lot and the take­off brief is both con­cise and com­pre­hen­sive. It in­cludes the pro­ce­dures to be adopted in the event of an en­gine fail­ure both be­fore and af­ter ‘blue line’ speed (the Vyse of 80kt) has been at­tained. We also re­view the other crit­i­cal air­speeds, such as the lim­it­ing speeds for the un­der­car­riage and flaps (even though we’re tak­ing off flaps up). He re­minds me that a good climb-out speed will be around ninety, that full power (+4lb/sq in boost and 2,550rpm) is lim­ited to a max­i­mum of five min­utes, and that the only hy­draulic pump is on the port en­gine.

Now al­though the An­son is a multi-en­gine air­craft, in com­mon

Pete has the only brakes and the tail­wheel doesn't lock

with sim­i­lar aero­planes of this era the sin­gle-en­gine per­for­mance is far from sparkling. In­deed, if you were fly­ing an early ver­sion by your­self, the non-feath­er­ing pro­pel­lers and an un­der­car­riage that had to be wound-up by hand meant that the only way to deal with en­gine fail­ure on take­off would’ve been to slam the other throt­tle shut and land ahead. So, al­though there are two of us, a hy­draulic un­der­car­riage and feath­er­ing props, if any­thing hap­pens to an en­gine low down that’s ex­actly what we’ll do. To fa­cil­i­tate this we in­tend to leave the wheels down un­til ‘land ahead’ is no longer an op­tion.

Care­fully, I align the An­son with Run­way 24’s cen­tre­line. Am­bi­ent con­di­tions are above ISA at 20°C and 238ft AMSL, and a sig­nif­i­cant ad­van­tage is that, with only three POB, lit­tle freight and half fuel, we’re some 1,200kg be­low the 4,717kg max­i­mum all-up weight. Neg­a­tives are that Pete has the only brakes, and the tail­wheel doesn’t lock, but on the plus side the run­way is wide, and there’s al­most no wind. I’m qui­etly con­fi­dent that as long as I bring the power in slowly and lead slightly with the port throt­tle I can keep it un­der con­trol with­out Pete help­ing with the brakes. Con­se­quently−and as there are 2,000m of run­way in front of us – I bring the power in very slowly, wait un­til the rud­der starts to bite then open both throt­tles up to +4 boost. The Chee­tah’s growl turns into a roar.

Check the revs are 2,550 and the air­speed’s alive, then slowly raise the tail. The com­bi­na­tion of ra­dial en­gines turn­ing big props means there’s a mass of me­tal whirling around on the wings, and gy­ro­scopic pre­ces­sion is not to be taken lightly. Pick the tail up too quickly and a swing is al­most in­evitable but−and as is so of­ten the case with tail­drag­gers−if you’re ready for the swing then it doesn’t come.

The air­speed con­tin­ues to build, the main wheels start to skip as the wing takes the weight, and at about sixty knots I ease the An­son into the air and hold it down, just above the run­way. Blue line is eighty, and as soon as the ASI’S nee­dle has swung past that I ini­ti­ate a very shal­low climb. Height may be ‘money in the bank’, but speed is money in your pocket, and the Vy is ninety knots. As the speed hits ninety, land­ing ahead is no longer an op­tion. Pete raises the plunger and, once the wheels slide into the wells, I bring the throt­tle and prop levers back to a rough ap­prox­i­ma­tion of +2 boost and 2,300rpm for the climb. Pete fine-tunes the power and I turn the An­son’s shapely nose onto a northerly head­ing.

It’s a glo­ri­ous evening, and at 2,750ft on the QNH I bring the power back to the ‘max con­tin­u­ous’ of +1 and 2,100rpm and re-trim. Talk­ing of trim, only the el­e­va­tor’s needs any at­ten­tion, and even then no more than one turn of the wheel. The ASI soon set­tles on 120kt, but the thirsty Chee­tahs are still drink­ing around 150 litres an hour. I, on the other hand, am drink­ing in the ex­pe­ri­ence. Gaz­ing out along the wing, past the bul­bous en­gine cowl­ings and proud RAF roundels at the English coun­try­side is a real treat, par­tic­u­larly as it looks stun­ning in the late evening sun, and the field of view from the ex­ten­sively glazed cock­pit is ex­cep­tional.

Once we’re clear of Farn­bor­ough I do as much of the usual Pi­lot flight test stuff as al­lowed. A cou­ple of turns with vary­ing an­gles of bank is al­ways a good place to start an ex­am­i­na­tion of the gen­eral han­dling, and this soon re­veals that the An­son flies like it looks; al­though the con­trols are rea­son­ably ef­fec­tive they are quite heavy. Even rel­a­tively steep 360° turns aren’t dif­fi­cult; the con­trol au­thor­ity is good and the con­trols rea­son­ably har­monised,

al­though the el­e­va­tor does seem to have more power than the ailerons. Un­sur­pris­ingly, di­rec­tional con­trol is good (but then the rud­der is huge) while, from a sta­bil­ity per­spec­tive, it is sta­ble lat­er­ally and lon­gi­tu­di­nally, and pos­i­tive di­rec­tion­ally. I don’t think it’d be too tax­ing to fly on in­stru­ments.

De­cel­er­at­ing for a look at slow flight is in­ter­est­ing−and deaf­en­ing! The un­der­car­riage warn­ing horn has clearly been stolen from a car, and as I re­duce power and speed with the wheels up it blares quite dis­con­cert­ingly. With a bit of flap and a drib­ble of power I ac­tu­ally get the ASI nee­dle flick­er­ing just be­low sixty, be­fore barely a tremor shakes the air­craft. It’s very be­nign.

For a look at the sin­gle en­gine per­for­mance I ask Pete to repli­cate a failed en­gine and feath­ered prop by set­ting the power on the port en­gine (the worst case) to zero-thrust. We’re clean (flaps and wheels up) and light (a long way be­low MAUW) but the den­sity alti­tude of over 3,000ft makes the test valid. I can in­duce the An­son to climb at 85kt, but just barely. The of­fi­cial RAF Pi­lot’s Notes (AP1525A), which I stud­ied as­sid­u­ously be­fore my flight, state quite clearly that ‘if en­gine fail­ure oc­curs be­fore the un­der­car­riage is raised, it may be im­pos­si­ble to climb away’−and th­ese notes were usu­ally writ­ten by men whose style was in­clined to un­der­state­ment. I’m quite sure that it would be im­pos­si­ble to climb with the wheels down af­ter an en­gine fail­ure, and that a sin­gle-en­gine go-around would also be ex­tremely fraught.

Pete sug­gests I might try a more spir­ited ma­noeu­vre to see what it’s like to dis­play an An­son, so I in­crease power to +2 and 2,200rpm, ac­cel­er­ate to 140kt (Vne is 185) and then pull up into a lazy chan­delle. Its fun but it’s not what an An­son is about and for the rest of the flight I elect to rum­ble se­dately across the coun­try­side at +1 and 2,100rpm and just soak up the am­bi­ence of fly­ing a vin­tage twin on a beau­ti­ful evening. The Chee­tahs are purring, the light is glo­ri­ous and I think that Pete is also greatly en­joy­ing the flight as we don’t even talk that much but just sit there watch­ing the world slide by un­der our broad wings.

Far too soon the giant air­ship sheds at Card­ing­ton ap­pear, ir­refutable ev­i­dence that our jour­ney is nearly at an end, and we’re soon slid­ing into the cir­cuit at Shut­tle­worth. Old War­den has been host­ing an aero­mod­ellers event, and as sev­eral are camp­ing overnight they are still fly­ing. Pete sug­gests I “make a bit of noise” to alert them that we in­tend to land, re­it­er­ates that I’m to go around at fifty feet and re­minds me that at only 85kt Vfe is quite low. The

wind­sock looks lan­guidly limp so we elect to use R03, which will al­low us to make full use of the run­way ex­ten­sion and also has the ad­van­tage (for me at least) of putting the run­way on my side, as it’s a right-hand cir­cuit.

As men­tioned pre­vi­ously, the first ap­proach goes very well, but as the in­ten­tion is to land this time I ex­tend slightly fur­ther down­wind. Pete low­ers the un­der­car­riage first, which changes the trim slightly nose-down and then adds some flap, which pitches the nose back up.

Af­ter a brief base leg, I set­tle the An­son onto fi­nal, dou­ble check that the props are set fully fine, glance at the brake triple pres­sure gauge, and then con­cen­trate on main­tain­ing the cor­rect speed and an­gle. The field of view is ex­cel­lent, and as we sail over the fence I add a pinch of power to ar­rest the in­creas­ing sink rate, pause, then slowly close the throt­tles while gen­tly eas­ing the yoke back.

“Don’t flare too high” cau­tions Pete, so I hold what I have, wait un­til we’ve sunk a lit­tle, and then ease the An­son into the flare and hold off. The touch­down isn’t bad, but weeks of drought mean the grass is like cor­ru­gated con­crete, and we bounce and skip a cou­ple of times be­fore set­tling down. (One of the aero­mod­ellers later told me it looked pretty smooth, so it prob­a­bly felt worse than it was.)

Pete ap­plies a cou­ple of deft dabs of brake, the An­son slows to walk­ing pace and a very mem­o­rable flight is nearly over.

We park over by the gate, run through the shut­down checks and I then pull out and hold the ‘Slow Run­ning/cut-out’ han­dle. Just like me, it al­most seems as if the An­son is reluc­tant to quit play­ing for the day, and the Chee­tahs con­tinue to growl un­til the fuel stops flow­ing and the en­gines die away into noth­ing­ness, ac­com­pa­nied by the whirring dimin­u­endo of the slow­ing gy­ros. Fi­nally, and with a de­gree of re­gret, I snap the big black Bake­lite Ground/flight switch to ‘Ground’. Magic!

Pho­tos: Dar­ren Har­bar

ABOVE: split flaps are pretty crude by post-war stan­dards

LEFT TO RIGHT: ready to crown the un­wary, the pitot head slung be­low the nose; and – rather ob­vi­ously an af­ter­thought – the ex­ter­nally mounted wiper mo­tor

ABOVE AND BE­LOW: the An­son was orig­i­nally con­ceived as a recce air­craft/light bomber. Af­ter WWII sur­plus air­craft were read­ily con­verted for the civil­ian mar­ket, com­pet­ing with Avro’s new-build Type 19

THIS PAGE TOP TO BOT­TOM: pho­tos taken dur­ing strip-down and restora­tion re­veal what lies un­der the skin – 159 litre wing tanks; the fus­lage’s steel-tube space frame (and rather in­tru­sive spar carry-through); wooden na­celle fair­ings (part cov­ered here); and one of the seven-cylin­der Chee­tah ra­dial en­gines, which each pro­duce 385hp

ABOVE, TOP TO BOT­TOM: fuel cocks are mounted on the star­board side, be­yond port-seated P1’s reach; de­tail of the dual ‘do­mes­tic light switch’ mag con­trols, con­nected by a gang bar; and a shot show­ing the rather in­con­ve­nient lo­ca­tion of the emer­gency hy­draulic pump lever, be­hind P1’s seatOP­PO­SITE PAGE: very ‘mil­i­tary’, even in Type XIX air­liner guise, the An­son’s cock­pit of­fers its pi­lots a fine view, if not much in the way of sen­si­ble er­gonomic de­sign

ABOVE: the An­son does not have power to spare and its sin­gle-en­gine per­for­mance is mar­ginal

ABOVE & BE­LOW: from some an­gles the An­son looks un­gainly, from oth­ers it looks grace­ful and even mus­cu­lar

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