Flight test: Blackburn B2
- Credit: Darren Harbar
Operated from Old Warden, BAE Systems Heritage Flight’s B2 is the only remaining example of Blackburn’s unusual side-by-side trainer, the launch pad for many an RAF pilot’s flying career | Words: Dave Unwin – Photos: Darren Harbar
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-by-side 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.
- 1 Civilian instructor qualifies as military QFI
- 2 Flight test: DHC-1 Chipmunk T.10
- 3 Irish Air Corps to train in the US
Like many light aircraft of the 1930s, early B2s were powered by a Cirrus-Hermes 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 ‘semi-monococque’ 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 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, centrally-mounted 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 ever-amenable 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 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 over-reading. (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 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 constant-aspect 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.
A memorable flight
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 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!