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.