This story from the Australian Aviation archives is from November 2011, when Owen Zupp took the classic Boeing Stearman on a flight test.
In the process of air-testing aeroplanes, occasionally more is involved than the pure handling characteristics and performance profile. Sometimes an aircraft type steps up and grasps the very essence of flight. Such is the case with the Boeing Stearman.
As days go, they don’t come much better. Clear skies and a light breeze made for perfect flying, while Southern Biplane Adventures’ scarlet Boeing PT-17 (A75N1) Stearman, VH-ILW, sat at the ready on the Albion Park apron. The chief pilot, Chris Clark, had obviously been there for some time, as readying a classic aeroplane for a day’s flying is a mix of muscle, motorised tugs and good old fashioned TLC.
As a past owner of the Commonwealth’s primary trainer in World War 2, the de Havilland Tiger Moth, I had long wanted to compare its US equivalent in the Stearman, as the two aeroplanes had trained so many fledgling pilots across the world.
Built in 1943, VH-ILW also had a significant military history, having been a primary trainer for the Tuskegee airmen, the famed African-American WW2 fighter wing. Such heritage only added to the mystique of the classic aircraft as Chris and I commenced a pre-flight inspection and looked at the aircraft’s finer details.
The first thing that strikes you about the Stearman is its apparent size, and yet when its dimensions are compared it is not actually a Goliath. Compared to the Tiger Moth, the Stearman is in fact shorter from nose to tail, but sits taller and boasts one and a half metres of extra wing span.
In more modern day terms, the Stearman is only marginally longer than a Cessna 152 with about 30cm greater wing span, although the top wing adds to the sense of size. Where the Stearman muscles out its opponents is in its sheer bulk, weighing in with a maximum takeoff weight of nearly 1200kg.
At 878kg empty, it is around 70 per cent heavier than the empty weights of both the Cessna 152 and Tiger Moth. Correspondingly, with a 220hp (165kW) radial engine at the front, it has twice the grunt of a Cessna 152. The Stearman picks up where the American cars like the Studebaker left off, with their sense of power and bulk.
Externally, the aeroplane seems well built for the rigours of primary flight training. Its fabric skin is stretched over a metal fuselage and wooden wings, but every cable, hinge, flying wire, strut and undercarriage component appears to be very sturdy.
There is no shortage of easily accessible inspection panels, and there are even “handles” built integrally into each wingtip to help move the aircraft around on the ground. It sits atop two large main gears that rely upon an air-oleo system as a shock absorber, and a tailwheel that is steerable up to 20 degrees of deflection before becoming castoring.
In the air, a substantial rudder and ailerons on the lower wings are responsible for directional control, and Chris warned me that like the Tiger Moth, coordinated inputs are required to combat the adverse yaw.
Up front, the fully restored 220hp (165kW) Continental W-670 radial’s seven cylinders are not housed in a cowling and glint in the sun. While ignition is a “shower of sparks” system, lubrication is via a dry oil sump.
Ingeniously, the chaps at Southern Biplane Adventures have an electric oil warming element that sits in the oil like a giant dip stick to maintain oil temperature when the aircraft is on the ground. Beside the oil filler cap is a fuel primer that injects fuel directly into the top four cylinders only, which explains why Stearmans sometimes sound a little rough on startup as the remaining bottom cylinders await their share of the appropriate fuel/air mixture.
Forty-six US gallons, or 176 litres, of fuel is housed in a central tank on the top wing with a simple drop-down visual capacity gauge. The fuel system is checked for quality at three drain points and the aircraft burns 55 litres per hour. Planning at 75kt TAS, the Stearman has the ability to travel about 240nm without reserves – more than adequate for today’s joyflights and yesteryear’s navigation exercises.
The nose of this particular aeroplane also boasts some impressive art. In a tribute to the Illawarra region of NSW that the Stearman now calls home, she has been christened Lilly Warra, and has both her name and an attractive lass finely painted on her nose. At the other end, aft of the cockpits, is a spacious locker with a 27kg capacity. Even with two people, full fuel and bags, the aeroplane remains within weight and centre of gravity limitations – an impressive feat that many contemporary aeroplanes can’t match.
Having looked at this impressive aeroplane from the outside, the time has come to see how she flies. If looks are anything to go by, this should be a flight to remember.
Entry to the cockpit is via a walkway on the left lower wing, although Chris and his crew have fashioned a set of steps that makes the task very easy for the joyflight customers they take aloft. Two integral handles on the centre section of the upper wing make access easy by stepping down into the cockpit.
Once seated, it is immediately apparent how much space there is compared to the Tiger Moth, while the cockpit sidewalls sit high above the shoulderline to keep the outside elements at bay. Within the cockpit, the fuselage’s framework and cables are not concealed by any internal lining, adding to the spartan feel of aviation from yesteryear.
To the left sits a throttle and mixture control, with a fore and aft trim lever a little lower down. The magneto switches sit on the left lower edge of the panel and the carburettor heat sits to the right.
The pilot is secured in the cockpit with a five-point harness and an independent lap belt over the top as a second line of defence. In the absence of a floor, two slender metal “walkways” run the length of the cockpit underfoot to the rudder pedals, which are fitted with conventional toe brakes. The instrument panel has an oil temperature gauge, airspeed indicator in miles per hour, a turn and bank indicator, a balance ball, tachometer, compass and G-meter. That’s it, and that’s all you need.
A call of “clear prop!” and the radial engine starts without hesitation, accompanied by the wonderful puff of smoke, smells and slipstream that only old world engines and open cockpits can offer. Without further ado, we move off and immediately I am struck by how easy the Stearman is to taxi. The forward view is obscured and demands S-turns, as with any tailwheel of note, but its directional response is fantastic and much easier than any number of castoring nosewheels.
We stop and complete our pre-takeoff sequences before moving to the runway’s end and lining up on Runway 34. Opening the throttle smoothly the aircraft accelerates, and in only a few moments the tail rises and the runway re-appears over the nose.
Passing through 65mph (56kt), the Stearman takes flight and the gentle throb of the radial engine and the sound of the wind in the wires let you know you’re alive. With full throttle and 80mph (70kt) indicated, the Stearman comfortably climbs away and its handling feels as solid as the aeroplane looks.
The aircraft is not heavy at all on the controls, but very stable. In trim, the Stearman is not at all tiring to fly and tends to ride the bumps far better than the relatively lightweight Tiger Moth. The other area of comfort where the Stearman wins out is in the slipstream stakes.
The Stearman cockpit is comparatively sheltered and flight in a baseball cap rather than a helmet is quite acceptable, although there is a bit of downwash from the top wing into the rear cockpit. Overall, it is a great aeroplane for open cockpit flying.
Levelling out, the power is reduced to 1800rpm giving around 85mph (74kt). As I begin to fly the aircraft in echelon on the camera ship, the Stearman’s stability is very welcome, while the struts, wires and top wing provide a great reference to “hold station”.
Free of the formation, the Stearman is a simple aeroplane to fly. Its pitch rate is proportionate to the control inputs, while the roll rate is a little slower than modern day aerobatic aeroplanes – I’d call it graceful.
The major difference relates, as usual, to the need for rudder input. In many modern aircraft, rudder pedals seem to be little more than a mounting system for toe brakes, but old-style trainers call for pilots to use their feet. Failing to do so will see a roll to the right met with a yaw to the left and vice versa. The amount of rudder input is not too substantial, but it is best to “lead” with the rudder input in the direction of turn and follow up with the roll via the ailerons.
Once in the turn and coordinated, the Stearman sits there nicely from conventional to steep turns. I admit to having to wake my own legs up and pedal a little at first before I got back into the groove, but once I was there it was sheer simplicity. You can genuinely see how so many young pilots were able to take their first steps aloft in the Stearman.
Climbing up to above 3000ft to a backdrop of coastline, parks and a lighthouse, the setting could not be better. Wheeling around the sky, we check for other traffic before flying the aeroplane into the stall. With the throttle closed and the carburettor heat “on”, the aeroplane gently decelerates as I note how smoothly the radial engine idles.
Back to around 50mph (43kt), the wind passing through the wires and struts creates a peaceful whisper as the aircraft starts to gently suggest it’s time to descend. Pulling the control stick all the way back, there is further quiet, a suggestive buffet and a very straightforward pitch down. The classic aeroplane demonstrates a classic stall.
Before heading back to the circuit, a glimpse of the Stearman’s aerobatic prowess is shown through a lazy eight, loop and barrel roll. It’s a true gentleman’s aeroplane when it comes to flying aerobatics, and the struts provide great lines of reference. It needs to trade height for speed in order to gain its energy, but the dive to 135mph (117kt) for the loop and the 4 G pull up offers a range of sounds and sensations that aren’t on offer in a closed cockpit. While capable of -3 G to plus +6 G, it is at home sweeping around the sky in the low-G manoeuvres and offers a wonderful sense of flight with the breeze in your face.
Flying back to the circuit, I take in the colours of the coastline while readying to join downwind. Positioning the Stearman parallel to runway 34, spacing is about where the strut joins the lower wing to ensure a safe distance from the field is maintained at all times. Turning base, the power is reduced to idle for the standard “glide approach” employed by the trainers of yesteryear. Trimmed for 85mph (74kt), I can’t emphasis how sweet the aeroplane is to fly on approach. On final, the runway is obscured from the rear cockpit and can call for a “slip” to keep the field and potential traffic conflicts in view. Coming over the threshold at 75mph (65kt), the control response is still very steady and I start to flare as the ground approaches.
Landing a tailwheel is generally considered the most difficult aspect of flying them, and with a long runway ahead we opt for a “wheeler” landing on the main gear. Sitting so high in the Stearman, I confess to feeling the main gear touch a moment before I expected, and while the touchdown was reasonable, I was pedalling to keep the machine straight with rudder. As they say, “It’s easier to maintain control, than regain it”. The roll out was rather ordinary and as I open the throttle for the touch-and-go, I’m a little embarrassed by my effort. Kindly, Chris doesn’t seem too concerned.
On the circuits that followed, I became increasingly proactive and less tentative with the rudder inputs before the aircraft could dictate to me. A degree of respectability had returned, but unfortunately after nearly two hours of flying, it was time to call it a day.
On the final landing, the speed was allowed to decay after touchdown and the tail settled softly onto the ground, cueing me to hold full back stick and bring the aircraft back to taxi speed. We clear the runway and move back to the Southern Biplane Adventures hangar before coming to a halt and shutting down. The handcrafted wooden prop comes to a stop, and with it so do the wonderful sounds and sensations.
With the magnetos switched to “off”, I paused for a moment. I just sat there. I reflected upon the sheer sense of pleasure such flying affords the pilot. I thought how privileged I was, that in a world of pressing schedules and commitments, I could step back to 1943 and grab a glimpse from the best seat in the house. It is the joy of being able to dawdle about the sky with no particular place to go and no particular time to be there.
For such a form of flying, it is definitely hard to beat the Stearman. Over 8,000 were built, and I won’t hazard a guess as to how many thousands of pilots it trained in war and peace. Needless to say, the numbers undoubtedly speak for themselves. Today, the Stearman offers that glimpse of yesteryear to pilots and passengers alike in a biplane that is fundamentally simple and very comfortable to fly. Whether an old hand, or a fresh-faced flier hearing the wind in the wires for the first time, the Boeing Stearman is definitely something special.
VIDEO: A look at the Boeing Stearman in flight in a 2012 video from BillBennettASC’s YouTube channel.
This story first appeared in the November 2011 magazine edition of Australian Aviation. To read more stories like this, become a member here.
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