An extended rest ends

November 2008 Since the last post, the big bird had not been exercised very much. A persistent flu on my part and several weekends of poor flying weather conspired to keep the bird in its roost.

Eventually, I did get a chance to haul the aircraft out of its hangar for a flight last weekend. As I pulled the prop through two blades, I felt an unyielding resistance - signifying a hydraulic lock. It was the first hydraulic lock I experienced for this bird, and it probably wouldn't be the last.

Having stood still for about seven weeks before this flight, oil must have flowed into and collected in the lower cylinders. Oil drain valves reduce but don't eliminate the chance of such hydraulic locks. Rather than pull the spark plugs from the lower cylinders, I gently moved the prop backwards a little until oil flowed from the drain valves and exhaust pipes.

When the flow stopped, I moved the prop backwards again until the oil resumed flowing and eventually stopped. Then I began pulling the prop through again and confirmed the lock had cleared. To be extra cautious, I pulled 24 blades (12 full revolutions) just in case residual oil remained to cause another lock.

After my tiring pre-flight calisthenics (ie prop pulling), I climbed into the big bird's cockpit and strapped in. Just before pushing the starter button, I hoped the extended rest wouldn't cause a difficult start as I wasn't in the mood for refilling the air bottles manually.

As I pushed the starter button, the customary "pop" sounded. Promising. Counting two blades, I then flicked both magnetos on. With a big cough, cloud of white smoke followed by a throaty roar, the trusty M-14P radial came to life and settled into its trademark "chug, chug" sound. Satisfaction. Boy, the Russians build dependable flying tractors!

The rest of the flight was fun as the bird metal bird was put through its usual exercise routine. I did monitor the engine instruments far more frequently than normal - just in case. In the end, the aircraft behaved very well. And finally, a good workout was rounded out by one of my smoothest landings yet in the beast.

Preparing for the Yak-50

November 2007 Russian prop aircraft like the Yak-52, Yak-50, Su-31 and Su-26, are fitted with the supercharged M-14P radial engine and use a pneumatic system to start the engine and power the landing gear. The Yak-52 pictured here belongs to Mark McNicol. He very kindly allowed me to use his aircraft for conversion training. An equally kind Steve Curtis offered to conduct my conversion training to radial engined and pneumatic system equipped Russian aircraft.


Although equipped with tricycle landing gear and weighing 315 kg more than the 50, the 52 (1305 kg MTOW) is sufficiently similar for conversion training to the single seat 50. Note the tall landing gear used to provide sufficient ground clearance for the big 2.4 m (7.9 ft) diameter propeller.


In terms of seating position relative to the 50, the 52's front cockpit is further forward. But for initial engine and systems conversion training, I started off in the front cockpit. Later on, I will move to the rear cockpit to get used to flying aerobatics from the rear cockpit.


The rear cockpit has a limited instrument panel. Note the Russian style attitude indicator (top centre instrument) in which the light grey "sky" is below the black "ground." In flight, when the aircraft's nose is raised above the real horizon, the artificial horizon (dividing line between the light grey and black sections) moves up above the fixed aircraft symbol (visible along the -20 degree pitch marker).


Compared to the layout of the 50's cockpit, the 52 is similar but different. One major difference is the location of the engine cooling shutters lever and oil cooler flap lever on the right cockpit console (seen on left side of the photo above). The emergency air valve (red knob) is also on the right cockpit console.


The left cockpit console contains the switch bank, flap lever, throttle and pitch levers. Another key difference between the 50 and 52 are the flaps - the former has none. Consequently, my flying in the 52 is conducted without flaps. I did make one landing with flaps and found they made very smooth landings easy.