Choosing my religion!

For pure flying excitement and adventure, you’ll find an Eagle hard to beat, while being well within the capability of most competent pilots. Nominally kit-built, they cannot be used for paid instruction, but you can easily convert in one of the many Pitts S-2s. If you can land an S-2, you’ll find this one easy. Then you can progress to aerobatics – displaying or competing right up to advanced standard, should you wish.

Moreover, many Eagles have smoke systems, so you can paint a smoke trail on arrival! I used to regard the Christen Eagle as a sub-standard Pitts, but that was quite wrong. The Lycoming AEIO-360 powered Eagle out-performs any similarly powered two-seat Pitts. And its cleaner airframe is roomier, more comfortable, more affordable, better finished, and has superior visibility. As an aerobatic two-seat biplane, the Eagle’s ability is only surpassed by the six-cylinder Pitts S-2B with nearly 50 per cent more power (but lower g limits).

The primary pilot occupies the Eagle’s comfortable and slightly reclined (for good positive g tolerance) rear seat. The front seat is a little more upright, but you both have sturdy five-point harnesses, with additional lap-straps for extra security. There is only one instrument panel, right at the front, where everything is in focus and visible at a glance from the back, although perhaps a little close for the front-seater.

Flying instruments are grouped around its periphery where the passenger’s head doesn’t obscure them.

The panel’s centre holds an A5 sequencecard holder, presuming that competition aeros would be flown solo. The only poorly placed indicator is the fuel sight tube on the tank’s rear face, ahead and up under the panel, where neither pilot can easily see it two-up. Both occupants have primary controls, including brakes and throttles, but only the rear-seater has secondary controls, like propeller rpm control, mixture, trim, intercom and radio.

Fibreglass and aluminium sheet side panels enclose both structure and control cables – neater and safer than in many other biplanes of all eras. A long, side-hinged canopy is firmly framed and damped by a slim hydraulic strut. It locks very securely both open and closed. You can taxi with the canopy wide open at low powers, enabling you to look well ahead past the engine for excellent tail-down visibility. Alternatively, you can swing the canopy closed without pushing it forward, directing a great cooling draught onto both occupants. Push it forward and lock it and you can be certain it won’t open. This is the best designed canopy I have ever encountered.

As you would expect, the Eagle’s controls have very little static friction. Both occupants sit quite close to the ground, but that wide engine is well ahead of you, the cockpit sides are low and the canopy sides are bulged, so visibility is comparatively good,even with it shut. And the front-seater gets a good all-round view too (and rather better than in an Extra) provided you have enough cushions under your backside.

The engine is standard fuel-injected Lycoming with all its foibles, and the propeller is a constant-speed Hartzell – both common and well understood components.

With no park brake, you simply press the pedals and crank the motor in lean. When it fires, go to rich, release the brakes and you’re off. That big four-banger makes its presence felt, rocking this light, compact airframe to its urgent beat.

Ground handling is often a good predictor of character, and this one’s surprisingly easy. Its steerable tailwheel is positive, tightly turning this short-coupled aeroplane, and can be unlocked with a kick for super tight turns; tap a brake and you pivot around one wheel. The brakes are good, as they should be to stop such a fast-landing aircraft, while the solid aluminium main legs are stiff but neither too rigid nor bouncy – the Eagle exhibits no waddle like some similar airframes.

The Eagle has such great control authority that any problems would be entirely self-induced.

To my surprise, considering the Eagle’s power-to-weight-and-size ratio, takeoffs are easy from grass or hard runways. Line up straight, add a bit of into-wind aileron, softly squeeze the right rudder, gently open the throttle, brace against the acceleration, ease up the tail to set the cowling top on the horizon (and see directly ahead), tapdance lightly on the pedals and you’re off.

I had expected a fight to stay straight, but found it no harder than my Maule to control – possibly easier. Okay, you can’t see much in the three-point attitude, but you can soon raise the tail, it comes up easily, and there is no tendency to bounce or swerve, nor any propensity to dart for the trees. The whole process takes seconds and perhaps 200m – less when you know it better and can increase the power more quickly.

Sitting so far back, you can utilise the fuselage’s whole length for instant indications of any veering tendency. Use the cabane struts as an aiming sight; pin them on the far threshold and hold them there.

The Eagle has such great control authority that any problems would be entirely selfinduced.

For my first attempt I tensed like a coiled spring, but it just is not necessary.

I’m starting to enjoy this! Within seconds part owner David Brown and I are at 1000ft, throttling back and reducing rpm while bending into the circuit. I needed a steady right rudder input in the climb, and now I discovered the Eagle’s Achilles heel. You do have to concentrate on its rudder, almost to the exclusion of the other axes. It is quite light and very effective, but the aeroplane has little yaw stability, so you are continually adjusting pedal pressures. Every change of power or speed requires a tiny correction – just like a Tiger Moth but more so – but this is absolutely the only similarity to that old warhorse. This aeroplane is much more powerful, capable and draught-free (unless you want ventilation, in which case you can get a blast of air from the side vents).

There’s not much to check on downwind in such a straightforward machine except for fuel and prop rpm; then it’s time to throttle back and start the approach. Rarely flying biplanes these days, I have forgotten the pleasures of viewing the world through a web of wings and wires. The downside is inevitably some reduction in forward visibility, but you sit well aft and can see all around – just not ahead without occasionally shifting the ironmongery.

I would prefer to make my first landing on grass, as I would in any fast, close-coupled, semi-blind tailwheeler, but the only grass runway available is too short for aninitial attempt so I have to make do with the long, wide bitumen runway of WA’s Murray Field.

I find a circling, slightly sideslipped approach easiest. Turning left puts the ASI just where I want it, neatly in my peripheral vision without having to refocus.

In a steady bank I can hold the runway continuously positioned between our left wings, giving me instant information about our glidepath, while some sideslip keeps the fuselage out of my line of sight. Control forces are light; both bank and yaw are steady and again that word – instinctive.

The Eagle flies its curved approach with minimal input from me – as though on spiral rails.

With all that biplane drag, the power off glide is too steep for comfort, so I use a trickle of power (15 to 18in) to modulate the comparatively steep descent of those highly loaded wings. I can tell by the balanced-on-a-pin feel that anything below 70kt will cause more sink, so I keep a vigilant eye on that ASI.

Eighty knots works well on base leg, reducing to 75 over the threshold, and this little lovely is surprisingly speed stable once you get the trim set correctly. Much faster and you’d have a long, blind float before touchdown. Slower and you might dig a hole if you didn’t judge your flare perfectly.

Crossing the threshold, a final glance confirms the airspeed trickling back through 70kt as I concentrate on straightening and flaring before we thwack into the numbers. Again, I am surprised at the ease of this manoeuvre, which can be quite tricky in some other short coupled aeroplanes. It seems almost automatic as I gently raise the nose to hold us at 10ft, while swinging it straight.

Squeezing some rudder to align ourselves precisely with the runway, I carefully hold the wings level, and then ease the throttle shut. The world is flashing past, and I can no longer see anything but Eagle ahead, but the runway’s edges are clearly equidistant and close below. They stay that way as I continue lifting our nose to the three-point attitude with my bum mere centimetres from the rough, abrasive bitumen.

All the controls are still very much alive, the aeroplane going precisely where I want it. Any deviation will be completely my own fault.

The speed quickly drops away, the aeroplane settling after a short float for a squeaking firm touchdown on those stiff legs. We must have been dead straight, because even with hard tyres there is no ‘dart for the dirt’. But of course I had to meddle, treadling the pedals unnecessarily in my tension, and giving us both lateral whiplash before I calm down and let it do what it wants, which is merely to roll straight.

I can see nothing but airframe directly ahead, although all but the very centre of the runway is still clearly visible on both sides.

Our rollout is becoming longer than I expected thanks to a rather high set tickover, so I pull hard back on the throttle to minimise residual thrust and brake gently, scrupulously applying identical pedal pressures. We gradually rumble to a halt. With these forward main legs, you would have to press the pedals pretty hard to raise the tail against such a powerful elevator held hard back.

Moving to the downwind side of the runway, I kick us around a 180 and backtrack for another go. We used perhaps 900 metres all told, so this is probably not a true short strip aeroplane, although less distance would clearly be achieved with practice. Did I mention we had a 40 degree, 10kt crosswind? But with these powerful controls, I suspect even double that would be no problem.

It was all much easier than I had anticipated.

Getting the flare and drift push off correct was the only challenge, and nothing like as hard as I’d expected. This Eagle was easier than many other aeroplanes I’ve flown (including the Pitts S-2A).

I flew a couple more circuits. They were each significantly easier than the last, although I was advised against wheelers – “They are difficult and unnecessary. ” Even a go-around from the flare gave no problems, with instant acceleration and climb, no tendency to pitch up or roll, and not too much yaw to counter.

Leaving the circuit, I timed our climb at 1100ft per minute at 75kt, much less than manufacturer Aviat’s quoted 2100ft/min (at an unspecified airspeed), but this is a well used example, with an 1800 hour engine. Others have been timed by experts at 1250, 1330 and 1440ft/min, so I don’t really believe Aviat’s claim, except perhaps at low weight. For transits, 23. 5in and 2300rpm represents 75 per cent power, giving us a comfortable 105kt cruise. Properly leaned, this should give two hours safe endurance or 200nm still air range from the 95 litre tank. The interior is roomy, but a bit noisy without headsets – this is definitely an aeroplane for ANR.

Nevertheless, it’s surprisingly comfortable, especially seated on my conformal foam cushions. The Eagle slices through turbulence so well you hardly notice any bumps. Your wings do tend to obscure much of the forward horizon for nearly 180 degrees ahead, but anything alongside can clearly be seen and, with its symmetrical aerofoils, you need only half roll to see everything below.

To my slight surprise, once trimmed out, it was actually possible to fly handsoff for a while. A ‘D’ shaped locker in the upper rear fuselage behind the cockpit carries up to 14kg of baggage – quite enough for a soft overnight bag for two, although you should be aware of this aircraft’s rear centre of gravity, deliberately designed in to afford maximum manoeuvrability. The battery can be moved forward from the rear fuselage to improve the aeroplane’s stabilities if required.

We did most of our subsequent flying at considerable altitude, in deference to my unfamiliarity and another shareholder’s comment, “Be careful Bob, it can be a bitey little mongrel!” But we had no real problems.

As you would expect of a potential advanced or unlimited aerobatic mount, the Eagle is barely (although still positively) stable in all three axes, with its particularly light and responsive rudder demanding careful attention at all times. The straight power-off stall came at 54kt with a slight tendency for either wing to drop, and a power-off spin was neatly entered and quickly recovered in half a turn to either left or right.

Yank, kick, push, whee, stop! Now for the fun stuff. Like most owners, David does all his aerobatic flying at around 85 per cent power, or 25in and 2500rpm, saving full power only for competitions. A simple loop is easy, with a steady 4g pull from 135kt, easing off to zero g over the top.

The fully inverted fuel and oil systems make all this stuff child’s play.

Half Cubans and half reverse Cubans are no more difficult, and you do not need to use anything like full aileron to make the upward and downward half rolls. About a quarter of full stick deflection seemed to be all that was required.

With a quoted 204-degree-per-second rate, level (‘slow’) rolls can be lightningquick or super, super-slow, while the required rudder/elevator coordination is not at all difficult with such powerful rudder and the Eagle’s excellent knife edge performance. Barrel rolls can be big or tight, while ballistic aileron rolls are childishly simple.

On the other hand, a stall turn requires some care and precise inputs, with a smooth rudder push (rather than a kick) at 40kt, but this is a boring manoeuvre without doing something else on the long up and down lines, as David demonstrated, his neat cartwheel topping a thousand-foot vertical 360 degree roll. David also flew lovely, long, level, eight-point rolls with dexterity and precision.

Positive flick (snap) rolls were straightforward too, and seemed quicker than in a Pitts (probably thanks to the Eagle’s more rearward C of G), although further experimentation in this diminutive but potent aeroplane should produce more standardised results.

My first flick was made at 90kt, two up, withhalf fuel, and in a slight full-throttle climb at 5000ft. Yank, kick, push, whee, stop – the Eagle snapped around its flick roll quicker than you can read this. That was such fun I did several more – frustratingly, none of the subsequent efforts snapped quite so cleanly as that first one. Next time I’ll try my favourite figure, the avalanche (a full positive flick roll at the top of a normal loop).

Other manoeuvres the Eagle is quite capable of include prolonged inverted flight (with no time limit) including inverted turns and Derry turns, outside loops, either upwards or downwards, downward vertical rolls (quarter, half and full) and negative flicks – indeed, in this competent machine, the whole panoply of advanced aerobatics is open to you.

Do you want to make a full vertical roll? Solo, Aviat says the Eagle can make two and a half upward revolutions, but two up we’ll be satisfied with just 360 degrees. So, fly south, accelerate to 160kt, pull 4g, check with a forward prod, and whack the stick against your thigh. Stop when you’re heading south again – that’s if you get it right, of course.

If, like me, you are unfamiliar with both the aeroplane and full 360 degree vertical rolls, you might lose it part way around, one wing sagging as you slightly topple over onto your back. Stop rolling, pull gently to humpty bump out of trouble as you would in your accustomed mount, get halfway through it and watch the upside down world inexplicably begin rotating as you wonder why the stick is being pulled forward in your hand.

Luckily, David spotted the ‘thinks’ bubble over (under?) my bemused head and intervened, closing the throttle and lowering our nose to recover. “I didn’t think we’d cover inverted, power on flat spins quite this early,” he laughed. “Whatever happens, if you lose it, just close the throttle and it will usually sort itself out. ” Despite that blunder, I did enjoy myself in this burly little biplane – indeed, no sooner had we landed than I arranged for a second go. Like so many before me, I had become an Eagle addict.

AVIAT EAGLE II

Technical specifications
(manufacturer’s stated)
Powerplant
One 200hp (150kW) Textron Lycoming
AEIO-360-A1D driving a three
blade constant speed Hartzell
HC-C2YK-4/C7666A. Fuel capacity
95 litres (91 usable)
Performance
Stall speed 50kt
Cruise speed 143kt
Max speed 160kt
Never exceeded speed 182kt
Roll rate 187 degrees/sec
Rate of climb 2100ft/min
Vertical penetration 1250ft
Range 330nm (612km)
Inverted flight time – unlimited
Weights
Empty 465kg
Gross 716kg
Competition 585kg (with pilot)
Useful load 251kg
Baggage allowance 14kg
Wing loading 12.62 lb/sq ft
Structural limits +6g, -4g operational
Dimensions
Length 5.46m
Height 1.98m
Wingspan 6.07m
Wing area 11.6m2
Manufacturer
www.aviataircraft.com