My all too brief affair with a wonderful Russian Starlet AVIASTROITEL AC5M RUSSIA SINGLE SEAT SELF LAUNCHING SAILPLANE ZKGPF By Roger Brown
The AC4 Russia was the ‘World Class’ design contest runner-up, to the PW5. Apparently many overseas journalists felt the wrong glider won. The AC5M is the updated motorized version of this glider. Introduced to one at Christmas time, Roger Brown fell in love with it.
being a big part of her thermalling success. She was a very easy aircraft to trim. The flight manual states her rate of roll as a 90˚ roll in 3.5 seconds, however at 51 knots I’d say this glider was quicker than that. It felt as if I was flying my own mini jet or ‘hot rod’ as far as her handling is concerned. Rudder control was positive and adequate. I did however forget to check out the aileron drag effect. It took no effort to
My involvement with this lovely Russian began when Thomas
balance the turns. Speed control was easy, but I found this little
O’ Rourke generously offered me a flight in his aircraft during the
pocket rocket really wanted to go if she was allowed to. I themalled
2010 Xmas Camp at Matamata.
comfortably between 45 knots to 55 knots, able to feel the ther-
ZK GPF has a very petite wingspan of only 12.6 metres, and a
mals as one does in say a KA6. She thermalled beautifully.
high aspect ratio of 20.6 giving an ‘average’ wing loading of 3.4 kg
So now let’s get down to the naughty bits shall we? Basic
per square metre. With her small wing area and relatively high wing
stalling, wing drop stalls, steep turns etc. The flight manual does
loading, I was very interested to see if she would climb and handle
not allow for spinning unfortunately. Basic stalling speed with my
our (at times) challenging Waikato thermals. She was fantastic. My
weight aboard was 39 knots IAS.
affair of the heart with this starlet had begun.
This sailplane is fitted with wing fairings. They obviously work
I decided to have my first flight as an aerotow launch, so as
well, as at the point of stall there is a little warning but no exces-
to get used to the handling before doing a self-launch takeoff.
sive buffeting. However it did want to drop its left-hand wing quite
The cockpit was spacious and should accommodate a variety of
abruptly as well as a noticeably pitch nose down at the point of
pilot shapes and sizes. On aerotow she behaved and handled very
stall. Standard recovery procedure applied, no issues there.
well. The controls were light and harmonious.
After thermalling back up to 3000 ft agl, I did a series of five
Once I released from the tow plane it was time to have a little
stalls with a variety of wing drop scenarios. All good. All predicable
look at the flight envelope and its parameters, whilst attempting to
and easy recoveries. Great stuff. Steep turns were a real delight
remain airborne. Fear not. This lady just excelled with her climb-
as one rolled from one 360˚ to another. A series of figure of eights
ing ability. She turned as if on rails, the controllability of the aircraft
once again reinforced her quick and harmonious handling qualities.
28
April 2010
