30 December 2008

Last workout for 2008

December 2008 Since late November until today, I hadn't flown the beast as much as I wanted. Owing to either gusty crosswinds, low cloud base or rain, the big bird stayed put in its roost. Yesterday, 29 December, was a case in point.

During my drive from home to Bankstown Airport, the weather seemed good for flying. Then as I strapped in, fired up the engine and switched to the ATIS frequency, I was disappointed to hear that thunderstorms were present to the north and west of Bankstown.

Not wishing to have the metal bird's wings plucked by a cumulo-nimbus storm cell, I shut down the engine and hauled the beast back into its roost.

Today, 30 December, started out mostly cloudless. But wind gusts up to 20 knots were forecast later in the afternoon. So I launched the sortie just before 1300 hrs, expecting to return by about 1400 hours.

Upon arrival over Warragamba Dam, I conducted a short workout before heading off to Mayfield; enroute to The Oaks township. The township is roughly due west of Camden and has a grass airstrip popular with ultralight pilots.

I arrived over The Oaks at 4,500 ft and then proceeded to climb to 7,000 ft while flying a racetrack pattern over some flat ground to the south-west.

This was going to be my first run at conducting fully developed spins in the bird. After completing my pre-aerobatics checks for the second time, I brought the throttle back to idle while holding altitude.

Based on a stall speed of 100 kph, the spin entry speed is 1.1 x Vs = 110 kph. So when the airspeed slowed to 110 kph, I applied full aft stick and full left rudder. After a momentary pause, the big bird rolled and pitched gently into a left spin.

Counting four turns, I relaxed the stick to neutral and applied full right rudder. The autorotation stopped somewhere between a third and half a turn after applying the right rudder. Easing back the stick and opening the throttle, I climbed back to 7,000 ft for a spin to the right.

Spins to the right are in the same direction as the propeller torque. And indeed, entry into a right spin is slightly quicker and exhibited a slightly steeper pitch down angle while spinning. Nonetheless, the entry was again smooth and gentle.

I was pleasantly surprised at the smoothness and gentleness of the spin entries; compared to the Robin and Marchetti, Yakovlev's beast is a mild-mannered pussycat. This isn't to say the Robin and Marchetti had aggressive spin entries. But in relative terms, the 50 is mild-mannered.

After the spins, I headed further west to Nattai. Passing Nattai, I arrived overhead Lake Burragorang at 4,500 ft for another aerobatic workout. Then it was time to head for home via a leisurely cruise up Lake Burragorang and then Warragamba Dam.

Enroute from the dam, I conducted my customary practice forced landing before heading back to Bankstown for an uneventful landing.

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