Finding the "right" aircraft for me

March 2014  My search for an aircraft to buy began around 2005.

It had been about four years after a Marchetti SF260 that I and a few other pilots flew regularly, became unavailable. A sleek, fast and good looking aircraft, the Marchetti suffered serious damage as a result of a forced landing due to engine failure soon after the Sydney 2000 Olympics.

With the Marchetti out of service, I had reverted to flying Robin 2160s - the aircraft in which I learned aerobatic flying. While a delight to fly, the Robin had its limits for outright speed, vertical performance - and sheer good looks. Also by this time, my CFI (ex-fighter pilot) had given up trying to get me into a Pitts Special.

In the Pitts Special, I saw very little attraction in flying the stubby and pig-ugly (at least to me) biplane. Its poor forward visibility compounded its overall lack of attractiveness to me. Of course, one's choice of aircraft can be quite subjective, since other people swear by the Pitts.

My Marchetti-less induced depression lifted at one point when it seemed like a Yak-52 would be available for hire. Alas, after many months of anticipation, it turned out that the 52 would not materialise. Predictably, my mood slipped back into a mild depression! Weeks turned into months and then into years of flying in the venerable Robin.

Sometime in 2005, I just got it into my head that if I wanted to fly something powerful and sexy, I'd have to buy it for myself. One initial pipe-dream was one of the new build Yak-3Us. Powered by an Allison engine rather than the original Klimov engine, these aircraft were a limited production run manufactured at Yakovlev's Orenberg plant using the original jigs and tooling pulled out of storage!

Why did I look at the exotic Russian Yak-3 rather than a classic western warbird like a Mustang, Spitfire or something similarly attractive? Price of entry into this most purist niche of aviation, of course. I couldn't afford the over A$1.3m ticket price for a Mustang - nice and mouth-watering it was and is to me! And with fuel price rising steadily, the typical 60 gallons/hr cruise fuel consumption of a Merlin engine reminded me that I didn't own an oil refinery.

One beautifully fitted out and maintained Yak-3M based in California was for sale at the time with an asking price of US$425k. A bargain compared to the Mustang. Then reality began to return when I learned the Yak's Allison engine also had a typical 50 gallons/hr cruise fuel consumption. Between looking at a Mustang and a Yak-3, I didn't inherit an oil refinery, so I eventually realised a scaling back of aspirations was in order!

I went to the opposite end of the spectrum by looking at a composite ultra-light class aircraft, the Silence Twister. Powered by a 120hp Jabiru engine, the sleek Spitfire semi-lookalike quickly captured my interest. Although it was broadly in the same performance class as the Robin, it looked a good bit better!

As I investigated this machine more, it did seem quite an attractive poor man's fighter. At around A$50-55k when fully completed and fitted out, the kit built Twister was a good bit cheaper than the Yak-3. But when I made some direct inquiries to the German manufacturer, their silence was deafening!

By around March 2006, I returned to looking at "regular" aircraft - ie non-kit machines. The main reason for my change in focus was driven by the amount of time required to complete a kit-built aircraft. And I had some reservations about how many people would buy an amateur-built aircraft, if I wished to sell it. I doubted that I would do so myself.

As I returned to looking at "regular" non-kit built aircraft, it became apparent to me that former Eastern Bloc birds offered better value for money than their western counterparts. The many proud Yakovlev, Sukhoi and Nanchang owners seemed to confirm my anecdotal impressions.

I flew a Nanchang CJ-6A to get a feel for its handling and performance. Surprisingly to me, even though it was a good bit larger than the Robin and the Marchetti, its general handling was similar to that of a Robin. Control harmony was very good and stick forces light; so there was much to like about the bird. 

In addition, the trailing link undercarriage made landing a smooth straightforward affair. The inward folding flush surface undercarriage looked prettier than the somewhat ugly forward folding protruding version of the Yak-52. But on balance, the Nanchang was only slightly better than a Robin in the vertical. 

So eventually, I narrowed my search to buying a Yak-50; which offered a reasonable balance between financial outlay, performance and warbird looks. In a nutshell, the Yak-50 was to me, an excellent poor man's warbird.

Trying to avoid bird strikes

August 2008 Winter this year has been a little less conducive to flying than the same time last year. Over the last few months, I had only managed to exercise the big bird about once every two weeks rather than every week. In most cases when a flight was precluded, the skies were generally clear.

But westerly to south-westerly weather patterns (typical during winter) created strong crosswinds exceeding the Yak-50's capability - or my comfort level. Although I often flew the Alpha/Robin with crosswind components up to 25 knots, I had over 200 hours experience in the tricycle landing gear aircraft. On the other hand, my less than 10 hours familiarity with the tailwheeled beast demanded caution rather than recklessness.

Sunday, 17 August, was one day during which the wind cooperated long enough for me to launch a sortie. Arriving at the hangar early, I dragged the big metal bird out into the brilliant sunlight. Completing the pre-flight inspection, I then proceeded with my pre-flight workout.

For radial-engined aircraft, pulling the propeller through before flight is vital if one wants to avoid hydraulic locks. Hydraulic locks are commonly caused when engine oil that has collected in the bottom cylinders, is not cleared. Since liquids are incompressible, the oil trapped in the combustion chamber acts like a solid block to a moving piston; leading to a bent or snapped connecting rod or complete engine destruction.

When fitted with suitable excess oil drain valves, pulling through a propeller clears any residual oil from the lower cylinders. The workout comes from pulling the propeller through at least six complete revolutions. It is not easy overcoming the natural compression of the nine cylinders.

Eventually, I arrived in the training area and flew the bird through its exercise routine. This time, I decided to use higher power settings of 75% rpm and 80 cm manifold pressure. Vertical performance along with fuel consumption rose accordingly. Rather than use a starting altitude of 4500 ft, I started at 4000 ft to avoid punching through the Sydney CTA lower limit during vertical manoeuvres.

After executing the usual practice forced landing, I pointed the bird for home. Approaching the Prospect Reservoir VFR checkpoint, I spotted two flocks of Ibises closing fast on a reciprocal heading. Bracketing me on the high and low sides, I had little choice but to maintain my altitude and hope they would do the same. Instinctively, I hunched down a little lower and hoped for the best.

The lower flock whipped past below and to the right of my right wing. They probably saw my strobe light and veered away from my flight path. On the other hand, the higher flock whipped past no more than 30 ft above my mid left wing. Fortunately, they did not dive as most birds seem to do instinctively when confronted with danger.

My arrival and recovery to Bankstown was much less eventful. Reflecting on the near miss, it seemed to me that flying a steady course and altitude at relatively low speed (130 knots) gave both flocks time to avoid colliding with the metal bird. Or I could have just been lucky.

Gliding like a Christmas turkey

May 2008 The last day of autumn, Saturday 31st May, was excellent flying weather; except when climbing up to 4500 ft to begin a workout session, I could see a layer of brownish light smog over the city and along the horizon. Nice!

On this sortie, one thing I wanted to do was use the big Russian attitude indicator to help me obtain the 45 degree inverted downline while flying a half Cuban 8. Competition aerobatic aircraft usually have angle sights mounted on each wingtip to assist pilots obtain the proper upline and downline angles.

But since no self-respecting warbird soils its wingtips with such untidy items, the non-tumbling attitude indicator comes in handy for obtaining the desired pitch angles when flying such manoeuvres. All it took was a quick glance to confirm the big bird was pointing 45 degrees downhill while inverted before stopping the pitch input and then rolling back to the upright wings level position.

I flew a number of consecutive full Cubans and reverse Cubans until I was comfortable using the instrument with its non-conventional (by western standards) reversed sky and ground display.

Next came flying a few Immelmans (roll off the top of a loop). While the Yak-50 manual nominates a 300 kph entry speed and minimum 150 kph at the top of the loop, it doesn't nominate a G loading for the initial pull up into the manoeuvre.

So I started with a 4G pull up and found that the airspeed at the top of the loop before rolling upright wings level was close to the 1G stall speed of 100 kph. The handling was mushy when rolling upright. It seemed clear the 4G pull up didn't deliver a sufficiently fast turn rate in the vertical plane before the bird lost energy at the top of the loop.

During the next attempt, I used a 4.5G pull up and it resulted in a 150 kph airspeed at the top of the loop. Handling was reasonably good when rolling upright wings level. With a 5G pull up, the airspeed at the top of the loop was about 170 kph. Satisfied with my findings, it was time for the main purpose of the sortie - determining suitable wing reference points for use during forced landings.

The previous weekend, I used a row of wing rivets (kept over the desired touchdown point when gliding to short final) between a third and a half wingspan inboard from the wingtip for my last partially successful attempt; which seemed to work until the landing gear was extended.

To compensate for the greatly increased descent rate with the gear down, I chose to start with another row of wing rivets at about half wingspan position. Conveniently, this corresponds to the inboard edge of the aileron. That's right, ailerons on the 50 cover slightly over half the length of each wing. On the Su-31, they span two-thirds of each wing!

Following Noel Kruse's advice, I also added 20 kph to the 150 kph best glide speed to provide better control and higher kinetic energy during the forced landing glide. I was pleased when the new reference row of rivets and higher glide speed resulted in a tight but successful arrival over the selected touchdown point.
t
tGeometrically, the 50 requires a narrower angled cone (compared to other less draggy birds) for a successful forced landing. Put another way, the Lift to Drag ratio of the beast is pretty poor due to the big paddle bladed prop! So the resulting geometry requires a tight spiral glide path to be flown to reach the touchdown point. And it becomes even tighter when a strong headwind is present.

For many years now, it has been standard practice for me to execute at least one practice forced landing during each sortie. With its Christmas turkey glide performance, the Yak-50 demands maintenance of this discipline. Being prepared is definitely better than being sorry.