Sunday, August 31, 2008

The tiger, the chicken and the Russian lady

I try to always have my camera with me when I come near an airport. Good blogging material may pop out of nowhere and be gone in an instant. A few weeks ago I was at Redcliffe aerodrome for my Nav7 briefing and my photographic obsession was rewarded with a visiting Yak-18T VH-KGU parked right in front of the Redcliffe Aero Club clubhouse.

No-one could be seen near or inside the aircraft, except for the guard tiger crouched over the right-hand seat. I walked around, took pictures and wondered at many of the peculiar features of this airplane.

The Yak-18 is a full-aerobatic trainer designed right after WWII ended. Remarkably, it is still in production today, although the later models are quite different from the earlier ones. The distinctive shape of the canopy of earlier two-seat tandem models make them easily distinguishable from the later Yak-18T and its four seats in a side-by-side arrangement. This model was designed as a trainer for Aeroflot pilots and production began in 1972.

It is painted in the so-called Yellow 44 Lilya Litvak livery, after the Yak-1B airplane flown by Russian WWII hero Lilya Litvak, one of the first female fighter pilots. The legend (or, perhaps more accurately, Soviet propaganda) has it that she had painted a white lilly on the fuselage of her airplane, which earned her the nickname "The White Rose of Stalingrad", probably from male fighter pilots who couldn't tell the difference between a rose and a lilly. According to IMDB, there's a movie currently in production about Lilya Litvak's life, to be released in 2010.

On the left wing is a half-meter long heated pitot tube, with an unusual pitot tube cover in the shape of a happy-looking rubber chicken.

The engine is the M-14P, a very reliable 9-cylinder radial engine that delivers 360 HP. It uses 45 litres of fuel an hour for a cruise speed of about 130 knots and a maximum take-off weight of 1503 kg. This is quite remarkable when compared to a more modern GA aircraft from the other side of the now defunct iron curtain, such as the Cessna 172SP. The cruise speed and fuel consumption are comparable, but the Yak-18T can carry nearly 350 kg more, is fully aerobatic, and costs a lot less to buy! Granted, the Yak-18T goes through half a litre of oil an hour, but that's part of the charm of radial engines.

And just like with most radial engines, the cylinder that ends up head-down after the engine is stopped has a tendency to leak oil. Which I think is the reason for the plastic Coke bottle at the end of the pipe. I'm not quite sure the Soviet Union officials would have approved of the use of such a blatant symbol of American Imperialism on one of their iconic flying machines though.

Looking up information on, I came across this page with a lot of practical information about the M-14P, including a discussion of the hydraulic lock problem, i.e. what happens when you start a radial engine that has one cylinder with its combustion chamber full of oil. Hint: oil is not compressible, and Fred Abramson in the article above describes what happens as "very dramatic, with the airplane practically jumping off the ground". Not good.

The propeller is variable pitch. VH-KGU seems to have the original 2-blade propeller. Modifications are possible to fit a three-blade propeller for increased performance.

VH-KGU also appears near the top of this Web page, both in its current condition but also as how it once was in the Soviet Union before making its way to Australia.

On the leading edge of the left wing, not too far from the chicken-guarded pitot tube, is a stall warning vane. When the angle of attack increases above a certain value, the vane is pushed upwards and triggers an audible warning in the cockpit.

There's an air intake right under the engine cowling and another one near the root of the right wing. Note that the size of the doors only covers the landing gear leg. As a consequence, the wheels are still visible when retracted.

The air intake on the right wing provides cooling for the oil radiator situated inside the intake. The white lilly can be seen on the door, as well as the name of Lylia V Litvak in Cyrillic characters.

Last curiosity: a pin located on the upper side of each wing right above the landing gear acts as a visual indicator that the landing gear is down and locked. It took me a while to find this one out until I saw it mentioned in a flight-test article on the Yak-18T written by Peter March in the December 2001 issue of the UK Pilot magazine.

So that's all I had to say about the Yak-18T. Great plane to walk around, great plane to blog about. A lot of what I know now about the Yak-18T I wouldn't have bothered looking up if it wasn't for writing this blog entry, so once again blogging is really a two-way street.

One thing that still bothers me though is that from the figures I've come across a Yak-18T could be cheaper to own and operate than, say a Cessna 182, for a comparable cruise speed and better payload. Either there's something I'm missing or there is actually an attractive and exotic alternative to the ubiquitous Cessnas and Pipers.

Not that I am in a position to even think about owning a plane. But it's nice to know that good engineering withstands the test of time.

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