Flying Machines 2. Two Seat Gliders

In 1969 I joined the Airways Gliding Club, later the British Airways Flying Club, Gliding Section. This introduced me to the idea of aerotowing gliders to launch them which in turn introduced me to tug aircraft. I will deal with the gliders first and the tugs in the next section.

Schliecher ASKa7 (Ka7)

Schliecher ASKa7 (Ka7)

At first I was trained on aerotow in the Schliecher ASKa7. A fine training glider with a major problem in that the instructor sat with his head between the leading edges of the wing roots which of course did nothing for his view of the World! However, I only had to fly from the front and after a couple of aerotows with the CFI, Norman Smith I was sent solo. The Ka7 was a much better sailplane than the Sedbergh.

I later did a small amount of passenger carrying in the Ka7, but never got really used to the view from the rear cockpit.

By the time I went work full time at Booker the training fleet had been upgraded to a pair of Ka13s.

The Ka13 is very similar to the Ka7 in terms of size, construction and performance, in fact from the front cockpit there is very little difference. However, the huge improvement was in the positioning of the wing to a mid position and giving an even greater forward sweep which enabled the makers to put the wing root further aft. The view from the rear cockpit improved enormously. I spent many hours flying the Ka13 and it is one of the few aircraft that, even after many years flying other aircraft, you can return to and it feels right straight away. The performance is good for a wooden winged two-seater, particularly at higher speeds which is possibly helped by the control arrangement which slightly alters the neutral aileron position by forward and aft movement of the stick.

Ka13 "201" at Booker

Ka13 “201” at Booker

The stall characteristics are by far the best of any comparable two-seater. It will stall, if you ignore all the signs, but there is a very gentle nose drop with no tendency to drop a wing. It requires a dedicated and competent instructor to demonstrate a spin and the aircraft recovers by itself after less than half a turn. I have twice witnessed a Ka13 stall close to the ground; in the first case there was no damage and in the second (caused by the aircraft being flown with the C of G way aft of the aft limit) there was no injury.

The aircraft in the picture, originally carrying the competition number 201, has been at Booker since the very early 1970’s and at the time of writing (2013) is still doing its job. I flew this aircraft in the Booker regional competition in 1978 and although I landed out a lot that week (twice on one day), I did manage to win a 1000 point day and a 150km out and return.

The Ka13 is by far the best two-seater training aircraft I have ever had the pleasure of instructing in or flying. They are still the mainstay of many training fleets over 30 years after production ceased.

The Slingsby T53, Later the YS53

The Slingsby T53, Later the YS53

The Slingsby T53 (it never got as far as a name), later regurgitated as the Yorkshire Sailplanes YS53 is at the other end of the scale. It was very much a result of the sort of aircraft design by government/RAF/Airlines that happened in the late 1960s. Since it had to be built by a British factory (Slingsby’s) they were given a design brief and probably a budget. The RAF wanted it built out of metal, a material of which Slingsby’s had almost no experience. To keep the cost down the wing was of constant chord, another “cut off by the yard” design. The result was appalling stalling characteristics; the spin had to be experienced to be believed. It certainly was not an aircraft to send 16 year old cadets off on their first solo and fortunately wise heads rejected it.

Its inclusion in this section is because it was at Booker that I had most experience in it although I had flown in the prototype when it turned up at Halton.

Apart from the stall, its other memorable trait was musical. It had a spring elevator trimmer which made a “Wing-Wang-Wong” noise whenever the stick was moved.

Booker did not keep their’s any longer than it took to sell it.

The Bocian

The Bocian

The Bocian was a typical Polish built glider of the mid 1970s. Mass produced and of wooden construction it was a serviceable enough glider, but it shouted cheapness at you.

They had clearly been produced many years before and stored until needed with the result that the wooden framed plywood covered fuselages were almost always looking “starved horse” with the ribs showing even when the glider was supplied “new”.

It had no particularly good, nor bad characteristics and I can remember little about it although I flew it quite a lot. I do remember that I avoided it whenever possible and was always glad to get back into a Ka13.

The Blanic

The Blanic

I only flew the Blanic a few times. It was made of metal, but built by the Czechs, so it was well designed and built. The main problem was the poor view from the rear cockpit.

It was really a 1950s design (well ahead of its time) and had very large landing flaps which also had some performance change. As with a number of “Iron Curtain” aircraft, its exact design purpose was not clear.

It was used by the RAF Gliding and Soaring Association at their main base at Bicester. It was, unusually, fully aerobatic and the RAF GSA Chief Instructor Andy Gough regularly did a display routine involving inverted low passes of the airfield, it went wrong one day and he was killed.

The Sheibe SF34 arrived at Booker paid for by the BBC for the BBC gliding club (those were the days!). It was the first one in the country and as such had to go through certification flying. Being of generous proportions, I was chosen to carry out the forward C of G spinning trials. With me in the front seat it would still spin, but recovery was normal and there was no shortage of up elevator in the flare for landing.

Sheibe SF34

Sheibe SF34

At the time I was a member of the BBC gliding club (my wife worked for the BBC) and flew it on several occasions and took it to Aboyne for wave flying on one occasion. The Booker club used to borrow it for spin training as it would enter a full spin, although it was not nasty. It had a slightly unusual trait in that as you opened the air brakes it would pitch up slightly as the air brake caps left the wing surface.

On one occasion Chris Rollings asked me to fly with one of the young ladies he always seemed to have near him and teach her spin recovery. On the recovery from the first spin the nose was slightly lower than was ideal and the speed was increasing quite fast At my prompting the pupil pulled a little harder and then at about 80 knots pulling about 2 g the air brakes unlocked and fully deployed by themselves. In any other glider this would not be a problem, but with the pitch up as they opened, the glider pulled a lot more g momentarily (I had a distinct vision out of the corner of my eyes of both wingtips flexing up alarmingly). The really worrying thing was the load crack that came from under my seat. We flew very gently back to the airfield and landed. With the glider derigged we could see some very obvious cracks around the pins that attached the fuselage to the wing.

It was Sheibe’s last chance in the glider market and they didn’t want to hear of problems. The obvious trigger event was the air brakes unlocking (which was easily fixed by adjusting the over centre lock), but this did not explain why the airframe had suffered some fairly major damage whilst flying below its manoeuvre speed. It never was explained. The damage was repaired and the aircraft put back into service. Since that date I have declined to fly Sheibe aircraft.