Staggerwing

Preparing the Staggerwing for our flight at the former Battle of Britain RAF station of North Weald proves slightly unusual.

First, we push Peter’s Mk XI Spitfire from the hangar. Then we manoeuvre his P-51D Mustang, using an old Fordson tractor.

That done, we can retrieve the Staggerwing from its month-long squat at the rear of the hangar.

The Staggerwing was faster and had a range greater than contemporary Army Air Corps pursuit aircraft. It suggests to me that this ‘Traveler’ warrants a certain amount of respect. In case there’s any confusion over names, ‘Staggerwing’ is the universally recognised popular name for the many models of the Beech 17, and the military version was dubbed ‘Traveler’.

Walking around the airframe, it’s clear that a great deal of attention has been paid to aerodynamic detailing, minimising drag – all the airframe lines are smooth and features rounded. The steel tube fuselage, containing both metal and wood formers, and wood stringers, is covered in Ceconite (polyester fibre). The fuselage is mated to the compartment in a continuation and blending of the circular form. I can see that there’s good visibility from the cockpit, which sits between the negativelystaggered wings (ie the top wing is set back considerably compared to the lower). The trailing edges are faired into the body. The generous width of the cabin is fluted to the tail – in level flight, the tall, rounded fin will rise to slightly above the height of the propeller.

The tailplane is cantilevered, although earlier versions were externally braced. The rudder has a short aerodynamic balance to aid rudder bar foot pressures and each elevator has a pronounced, long armed mass balance protruding forwards from underneath, at a rakish angle. This certainly moves the centre of gravity forward of the hinge line to prevent any chance of flutter.

This one feature points to the era of its design – these weights could have been hidden from view by being centrally mounted on a lever arm inside the fuselage. Each elevator has also a cockpit-adjustable trimmer and I notice that the elevators appear to have more downward travel than up.

The main undercarriage and tailwheel are fully retractable and the gear doors fully faired after retraction. Not many WW2 fighters, even, exhibited such faired undercarriage doors. Having a fully retractable tailwheel and a set of faired doors was undoubtedly very advanced for the 1930s.

The wings are of wooden spars and ribs. They have rounded, almost elliptical wingtips, although it’s only the last seven of 21 ribs that are tapered. The ribs are very closely packed together, being just over15cm apart. The upper set of wings has the ailerons and the lower set has flaps, an unusual feature for a biplane. As we move the aircraft, the lowered flaps are noticeably close to the hard ground. I suspect on muddy surfaces these get spattered with mud from the main wheels.

The flaps and ailerons are mounted in exactly the same position on their respective wings, and one could be forgiven for thinking that there are four ailerons – it must have made construction easier, although the wings are not interchangeable due to the undercarriage. The Frise ailerons can be moved up further than they can down – I’ll soon see how well these remove the effects of adverse aileron drag.

The wings’ negative stagger really is the visual feature that distinguishes this aircraft instantly from others. The arrangement offers a good field of view for the pilot, particularly looking into the turn.

The flying and landing wires are of an understandably broader aspect than I am used to on smaller biplanes, as are the interplane struts which cope with higher weights and loading. These struts appear bulky from the side but are very slim seen head on. The standard arrangement of two interplane struts per side, supported from the two wing spars of the upper and lower set of wings, provides a strong box structure, but creates drag. These rearward-raking struts emphasise the backward stagger.

Each main undercarriage wheel is sprung by a seemingly oversize, vertically mounted spring on each wheel. This does work well, giving a soft ride according to Peter, but he warns that at slow speed, over a series of small bumps, they can set up a series of less-than-damped bounces, then all you can do is keep the stick back and ride them out.

The undercarriage is inwardly retracting.

The 12 volt system turns whirring ‘bicycle’ chains that activate a slider bar and raise the gear in 13 seconds. By using a climb speed of 80mph (70kt) directly after takeoff, the gear-limiting speed of 110mph (96kt) may be easily avoided and place less strain on the system – not a bad thing in a cool climate as the engine temperatures are not overly affected for the short period.

There are toe operated hydraulic brakes that use pucks. The brakes are only fitted on the left hand side of the cockpit.

The adverts said, “The world is a small place in a Beech. ” So let’s look at the fuel and range. There are five fuel tanks, one in the fuselage and one in each of the four wings. There are three fuel pumps, a wobble, electric and mechanical. There are two fuel selectors and one fuel contents gauge.

Balance those! The total capacity is 568 litres. At a rate of 82 litres/hr at 155mph (135kt), that’s just over 870nm in 6 hr 28 min – figures demanding a lot of stamina and great faith in the fuel gauge and knowledge of unusable fuel amounts.

568 litres of fuel weighs 408kg. To put it mildly, that is both a lot of fuel and weight and the Staggerwing’s tare weight is 1270kg. Its gross weight is 1927kg, which means theoretically another 250kg can be carried, ie three adults. The baggage compartment behind the door can hold 57kg. This machine was really designed for an executive to fly himself in comfort and speed.

The large, chromed propeller spinner reflects our outstretched arms as we pull the blades through. The nine compressions all feel fine. There’s no oil resting in the lower cylinders to threaten any hydraulic lock.

I mount from behind the left lower wing into the rear of the cockpit, which is roomy and comfortable. Each side, at the front, has a small, wind down quarter light. The seating is brown hide with wood cappings.

The rear bench seat can hold a friendly three.

There’s only one control column, a throw-over affair with a yoke hinged on a centrally mounted column. Dual checkouts could have moments of interest.

There are rudder pedals in front of both seats, so I’ll have a full set of controls when the column is, literally, handed over to me.

The left hand set of rudder pedals has a pair of manly footplates to combine the rudder bar with toe brakes. The right set lacks brakes.

An array of knobs protrudes. The collection is more than the standard – there are the prop, mixture and throttle engine controls, and below the instrument panel are four more of a similar size. I try to work these out as I strap into the right hand seat. . .

The engine is started on the central tank, fuel flow is established on the other tanks, and then the central tank is reselected for the takeoff. The selectors are at knee height on the right fuselage wall, so the pilot has to lean over and adjust both selectors, reaching across the passenger. Fuel pressure, prior to the start, can be raised by a wobble pump sited on the same, right fuselage wall. . . hmm. Fortunately there is the option of using an electrical boost pump to charge the fuel lines.

Mixture rich. Then priming is a slow and steady process of easing the fully charged Kigass primer in, pull it gently back as it squeaks and refills, pause as it recharges and ease in again – five squirts in all. The throttle is barely opened, the mixture pulled back to lean and the carb heat is set to cold.

Open the bird box

“Clear prop. ” The black faced prop arcs by, clockwise, viewed from the cockpit.

Mags on. She fires straight away. Ease the mixture lever in and, instead of further priming to keep her going, milk the throttle ever so gently backwards and forwards.

The engine runs at minimum revs and the oil pressure is just off the stop, the white needle barely twitching and flicking in time to passing blades.

She almost dies. . . the engine and prop are still turning, but without firing, andthe gearing can be heard. Blip the electric primer, rock the throttle, and she fires smoothly and runs again, revs at 400.

Our Staggerwing is a little reluctant to rush into life, but the gaps between idling, without running, priming and nudging the throttle backwards and forwards with minimum movement, become shorter and shorter. She is coaxed into a gentle low rpm and almost too slow a burble.

We ease the prop into fine pitch and the rpm rises to 800. The oil within the engine is obviously warming during this process and when 20°C is reached, the cold and thicker oil from the large sump is slowly introduced and circulates by easing the oil bypass knob forward. This lever is the same size as the other, albeit labelled, extra control levers that I’d wondered about.

One operates the cockpit heater. Another is connected to the ‘bird box’, the boxshaped intake with an opening flap near the top of the engine. This control, when back, has the flap closed allowing the oil to warm up. As the temperature rises, the flap is opened, keeping the oil within the 60-75°C range.

The start has been a lengthy process. . . so much damage can be created with a rush to high revs in any engine upon startup, especially so on a cold, oil coagulating day.

The Staggerwing’s tailwheel is unlocked prior to taxying by a laterally activated lever, with a ball on it to identify it as being connected with steering. This is sited at the base of the instrument panel and very closely, perhaps too close, to the gear selection handle. The undercarriage selection lever has a similar ball on the end, but at least its movement is up and down. I would hate to mix them up. During the turn, the stick is eased forward simply out of mechanicalsympathy for a wheel at the end of a long lever arm that may have its effective weight increased as it is turned into wind should the elevators be raised. Simple airmanship, common sense and mechanical empathy.

There is no published crosswind limit, but there is a published taxi wind limit.

Taxying on a calm day, on an even surface, poses no problems beyond the need to turn to see the view ahead.

Brakes on. The throttle is eased forward, the noise increases from a smooth, idling rumble to a more forceful gravelly voice as the power is increased and run to 22-inches/1600 rpm. Carb heat is checked, the revs remain the same but the manifold pressure drops very slightly. The prop is cycled to coarse pitch, down to 1300 rpm, the tone drops, the oil pressure dips and the manifold pressure rises to 24in, showing the level of work needed to change the angle of the blades. . . and the prop vernier lever is returned forward to fine. 1600 rpm is restored, the manifold returns to 22in, and the oil needle also returns to its higher indication. Mags are checked, the drops being smooth and even.

Vital actions include ensuring the bird box is open, electric flaps down and the tailwheel now locked for takeoff.

I find the takeoff roll directional control easy to maintain during the initial acceleration, and when I raise the tail she readily flies herself from the runway. What surprises me is the little distance we use – I estimate a tad short of 300 metres.

“Eighty mph is a good compromise between climbing at a good rate and allowing the gear to come up. ” Peter selects the undercarriage lever – it is closer to him – and the yoke and column are in my way.

Power and rpm reduce from 33in and 2250 rpm to 30 and 2000 as soon as the undercarriage is raised – with a muted whirring beneath our feet, as twin cranking sets of sprockets and chains raise the wheels. A retraction sequence is often ended with a thump as the wheels lock home, but not here. As the sounds stop, Peter winds a red handle, way out of my reach on his left cockpit side, to ensure the gear is fully up. A red light shines in confirmation and Peter secures the handle with a leather strap.

I trim slightly forward for a higher climb speed. We are not in a race and can look after the engine. We are light, I estimate about 385kg short of max all up weight.

BEECHCRAFT D17S
Technical specifications
Powerplant
One 450hp (335kW) Pratt & Whitney
Wasp Junior R-985-AN-1
Propeller: Standard Hamilton
Performance
Max speed @5500ft 184kt
Cruising speed @10,000 feet 175kt
Max climb, s/l 1250ft/min
Service ceiling 20,000ft
Range, no reserves 935nm
Weights
Empty 1270kg
Mtow 1928kg
Dimensions
Wing span 9.76m
Wing area 27.5m2
Length 8.15m
Height 2.44m

Book figures would give a max rate of climb of 1250ft/min, but we are level now and sailing along – 18in and 2,800 rpm – to slide into position alongside the Yak-52camera ship and maintain 130kt. Upper left fuel tank selected, close to my right knee, pressure still good and pump off.

Our photographic manoeuvres confirm an exceptional field of view, and it is so easy to hold formation, both high and low in the turn from either seat.

With a clear sky and horizon ahead I hold the yoke gently. In fact, hardly at all, just holding the edge of it without imparting any fore or aft force and watch the horizon remain in the same position above the cowling, between the wings and alongside the struts. This is a well-trimmed aircraft with constant speed, constant altitude and balance, with the ball remaining in the middle. True, there is no turbulence, but she sits here, arrowed in a straight line, with the ASI fingering 160mph (139kt). I am comfortable too! It’s a good seating position and the heater is pumping out ample therms. A real luxury. No bulky sheepskin clothing needed today.

Ah, that trimmer, it’s a knurled metal knob the diameter of a large jam jar lid, but substantially chunkier and positioned on the right of the column. I have been flying with my right hand and adjusting the trim with my left, but when the control is in the ‘thrown over’ position, the elevator trim is in the elbow crook of the arm supporting the yoke and I find it easier to swap hands and trim with my right hand.

I ease the nose down 10° and allow the speed to rise by another 10 miles an hour to 170 and then I let go of the yoke. Slowly her nose rises, looking for the trimmed speed. The speed falls as height is gained until the indicated speed is less than the trimmed speed and the nose goes slowly back, looking for the original cruise speed.

She performs two more slow and lazy cycles until she is straight and level again, at her trimmed speed, but just 100ft lower than when we started the game. Now we continue to sit here, same heading, height and indicated speed – this is certainly a stable machine to travel in, built as a comfortable cruiser.

There is no pronounced evidence of the adverse aileron yaw that the differential and Frise ailerons were fitted to fix, just a smidgen of nose swing away from the turn.

(It would be more pronounced with a long nose diverging across the horizon. ) You can normally bully a machine to show more aileron drag by first rolling one way and then, with feet still planted, rolling promptly in the opposite direction. I thought I might have got more reaction but I appeared to get less wayward yaw. And that does surprise me. The lightness of pressure I need to exert on the rudder pedals, for balanced turns, enhances the feeling of secure and stable cruising. Yoke rolling pressures are not high and although the responding roll rate isn’t fast, it’s certainly manageable – no problem in rolling out on a specific compass heading. Like everything else, a little anticipation of an unfamiliar machine’s reaction time is soon learnt. Time for a fuel tank change.

Now, I’ll try and upset her.

I pull the power back slowly to just above idle as I complete a turn and roll out onto my feature. Bird box closed. Carb heat on.

As the speed decays and I retrim, we pass below 90 mph, still keeping our height and slowly, ever so slowly, the speed slips away as I bring the nose higher. This is taking a long time. I think of a heavy vintage car, with bags of inertia. The throttle is now fully closed – radials have only one set of bearings and the time of airborne idling,when the wind is pushing the prop around, should be kept to an absolute minimum.

Eventually she indicates that she is tired and with a slight nod of her short nose, together with a slight ruffle of air over her lower wings, she starts a gentle series of little pitches – still with the yoke held back against the stops.

Now that she has let go, the ASI needle shivers and flickers around the 60 mph mark. I hadn’t felt any trembling through the elevator circuit on the yoke, and there’s no stall warner. She is now grand pianoing downhill with gusto. It doesn’t feel like it of course, but the VSI certainly knows all about it. I maintain directional control, correcting the slight meanderings by applying rudder harder than in balanced turns.

Recovery is proving simple, easing the yoke forward, power on to maintain flight and altitude, right rudder to balance the torque, bird box slightly ajar and carb heat back to cold. I am mildly surprised that the stall with gear and flap down occurs at the same speed – but I expect and get a little more grumbling and a tiny wing drop. Time to change a fuel tank.

I ask Peter to show me his aeroplane and with the yoke swung over to the right he runs through his display practice with fast straight passes, simulating a run along a runway, an impressive climb linked with wing-overs, steep level turns and curved flybys to show differing sides to the simulated spectators. To reduce control forces he is trimming with his right hand throughout the sequence – but at no time is the rudder trim adjusted, despite the range of speeds flown, from 80mph (70kt) in the wingovers and 225mph (195kt) in the first level pass. I had noticed the rudder trim on the walkround – it is only a luxury and it is not needed in this flight. I imagine that should a long, prolonged climb at full power be required then the rudder trim might be of benefit to ease the force. Perhaps that was a good selling point, a feature to emphasise, showing this was a powerful and fast machine.

Time again to change a fuel tank beside my right knee. It’s a strange sensation swinging the yoke over. For that minuscule moment I do feel disjointed and awkward – two of us are in contact with it at the moment of transition.

I have control again and head back towards the circuit. The idea is to think ahead as we have to lose height and reduce our cruise of 160mph (139kt) in order to lower the undercarriage and flaps. Limiting speed is 120mph (104kt). The simple expediency of chopping the throttle doesn’t fit here, and not just for the rapid cooling aspect.

Being a single row radial engine, there is just the one set of bearings – the throttle shouldn’t be fully closed but kept under power. If it is not, then the prop is turned by the rushing air and slow but progressive damage is done.

Fuselage fuel tank selected and boost pump on. Peter selects the gear down and there’s the marvellous clatter of the seemingly Heath Robinson sprocket and chain.

He winds the gear tensioning handle and secures it in place by its strap. A green light confirms wheels down and locked.

We join crosswind and turn early onto base. Full flap now and the speed back, almost automatically, to 80mph (70kt). The mains touch first and, still with a touch of power, she settles smoothly with the tail just off the tarmac. The tail sinks, the throttle is closed and the stick held fully back. She runs straight but there’s lots of pedalling at the end of the run.

Peter takes over and brings the flaps up before we turn off the runway – should the outside leg sag during the turn it’s possible that a flap may strike the ground.

Taxying in is followed by a cooling period, run at 17in and 1000 rpm, and shutdown by pulling the mixture to lean.

Beech gave the Staggerwing a combination of features and the attention to detail that ensured a practical touring aircraft, with both a high level of performance and comfort. It undoubtedly succeeded in its chosen design role and catered for its narrow market and achieved sales.

The college tutor I quoted, Dr Jackson, would have admired this machine’s creators. It is a delight to fly and a potent high speed cruiser with some idiosyncratic systems that require forethought to operate – idiosyncrasies highlighted by modern hardened runways that are invariably out of wind.

It is an aircraft of a previous era, which was replaced by one of all-metal construction – the Bonanza. Check the performance figures, they are remarkably similar. n