Down Memory Lane - From the Log Books #3

[Guest TOSGcentral]

This time we will take a look at the evolution of UK two seat trainers. All of the main types that have descriptions (rather than just a passing reference) are, or were, also present in Australia.

 

 

Some Background.

 

 

Although UK held its head up well enough by world standards, the nation just did not have the flying ‘drive’ of the Germans for average people to get into the air cheaply – with gliding providing a useful channel to do so.

 

 

For flying training in any volume you need manufacturers who will produce, develop and support types. In UK, with a small demand market, there were only two real market contenders – Slingsby Sailplanes and EON. Slingsby supported training and produced a succession of new model two seaters in parallel with continuing single seater development and aircraft specifically aimed at backing up the two seaters in a progressive, experience growing path that gliding clubs could control easily.

 

 

EON confined itself to single seater sporting gliders and did very well in that area. But more on these types in other stories perhaps.

 

 

There are always people who want to cut the mustard so there were other UK two seater designs. The most notable were the Short Nimbus (large gull winged design). The Kestrel (not the Slingsby Kestrel) and the Peak 100. All of these machines had only single examples built and all were high performance two seaters. The Peak 100 was intended to go into series production as a trainer and had the Peak 200 (a single seater) intended as its stable mate but none were ever built.

 

 

So we are basically down to what Slingsby produced. Here, in type order, is what I have had experience on.

 

 

T21.

 

 

This post WW2 two seater was basically a x1.5 scaled up Grunau Baby with side by side open cockpits. It was certainly a big glider with a huge, strutted parasol wing sitting on top of a pylon and sporting a 16.5 metre wing span. A later modification was a fully enclosed cockpit via removable hood side panels and these worked well if you had to work in the things in all weathers. Construction was all wood and fabric.

 

 

It was originally intended for Air Training Corps (ATC) use but proved to be too high a performance (!!??) for the training regime that was in force. This was not because of glide angle or penetration because the machine had little of either – but because of the low sink rate. The glider would float about quite a bit and time equals decisions and the training was orientated to some quite clear cut decisions that could be taught quickly and safely for the task required.

 

 

Although the ATC used quite a few T21s they were mainly relegated to “advanced trainers†and staff flying.

 

 

But the floating about bit appealed greatly to the civilian clubs so a market was also found at club level and the T21 in fact became a mainstay UK trainer and persisted for many years.

 

 

I flew and instructed on quite a few T21s of various forms. They were all pretty much of a muchness – just a docile, low speed old lady. They seemed to do anything with an air of grace. They were light on elevator, very positive on rudder, had a lot of aileron drag and were slow in roll. The small spoilers gave adequate approach control. They would stall and spin (with some decorum) so basically had what you needed as a trainer.

 

 

In the ‘sharper’ areas it could be a bit different. You should not really operate low speed aircraft in conditions where you have to have airspeed to beat wind gradients. I had T21s up to aileron reversal at rough air speed in high turbulence wind gradients and it is not pleasant as you are busy enough without having to mentally work out why things are back to front! The problem with that was full aileron deflection in concert with the huge wing area had the wing chord deflecting and neutralising the aileron.

 

 

Equally I watched a good mate spin Upwards tail first into a thunderstorm. He had got too close could not fly fast enough to beat the updraught so span it and held it in a full spin but it still went up! Took a few beers to calm him down after he got down. Whatever turns you on I guess!

 

 

T31.

 

 

This was contemporary with the T21 and a bit later. Once again it was primarily aimed at the ATC market, or any market where straight forward procedural flying was required with no great amounts of judgement required. But the type was of much lower performance than the T21 and was considerably smaller. It was in fact the aircraft type that I first flew solo in.

 

 

The basic concept was a winch launch to maybe 1000’, fly an oblong circuit, pull the spoilers and land. They got a huge amount of kids as solo pilots! Damn we wore those who wanted to continue later and came up against that magic word ‘judgement’! But the basic concept was OK – churn out ‘solo pilots’ and some would later stick with aviation – meantime that achievement was doing them no harm at all.

 

 

In layout the T31 was all wood and fabric. A 13.2 metre parasol wing on a pylon with double lift struts each side and quite a heap of struts and bracing wires here and there. The cockpits were totally open and rudimentary. The front seat was extra cramped because you had to wedge your butt between the boxes that held the instructors’s rudder pedals (That was OK I was slimmer then!).

 

 

For a simple cockpit design the ergonomics were a disaster. There were two identical shaped and sized knobs (hanging on the end of cables) that dangled from the port side of the instrument panel. One was the cable release and the other was the spoilers!

 

 

So naturally we had people who frantically hauled the spoilers in and out trying to get off tow, and we had an equal number who ‘shot’ past the launch point with full cable release instead of spoilers. They never went all that far but did so in the certain knowledge of the penalty – a full round of drinks in the club bar after flying to pay for pushing the glider back.

 

 

The stall was docile and the machine would spin but reasonably benignly. All of my initial spin training was done below 1000’ agl although I was checked later in a three turn spin in a Ka2 to make sure I could remember which way was up. This would stand me in good stead later when instructing where I had little fear of, and a great deal of motivation to, get solid training applied in low level emergencies that I went on to specialise in.

 

 

For such a simple machine I learnt a great deal despite the very poor level of instruction available at that time and place. I learnt a lot about visual location of controls prior to using them or when checking them. I learnt to operate gliders close to the ground – not for exhibitionist flying but because we had to!

 

 

If I never fly a T31 again it will be too soon but damn that little bastard was a learning ground! I never did much time in them but a lot of flights. At 2 and 3 minute circuits you can learn a lot fast.

 

 

T42 Eagle.

 

 

At 18 metres and up to a 30:1 glide angle this plywood monument to UK gliding progress sort of missed the market target of a potential advanced trainer for the ATC. So only few of them were built and those that were filtered into clubs or private hands.

 

 

The Eagle was up to Kranich size but considerably less elegant in appearance. A big three piece wing that you definitely did not want to take apart too often, requiring a trailer that you could sleep a small herd of cattle in, and something very formidable to tow the thing - all of this added up to not a very practical machine. But I had to fly one!

 

 

It was actually not much of a flight – a hurried 800’ auto tow at Lasham when the ASK13s were going to 1200’ easily. Anne Welch was in the back and did not say much so I suppose it was OK. The front seat was spacious to say the least yet everything came easily to hand.

 

 

With that brief exposure to the Eagle I came away thinking that it would be superb off aerotow on a good day and would really go places – but how many good days did we have in UK? They should all have gone to Spain, South Africa or Australia where they could be used!

 

 

In keeping with Slingsby’s later production aircraft the Eagle was solid and stable in the air, trimmed beautifully, the massive airbrakes gave precise approach control and it landed easily. Slow on roll but otherwise with well balanced controls for a glider.

 

 

I would have like to have done more in her, and on a good day, but it was never to be.

 

 

T49 Capstan.

 

 

Capstan is an odd name for a glider and came about in tribute to the Player’s cigarette company who put financial aid into the project and produced a cigarette brand named the Capstan.

 

 

The T49 was intended as a new generation trainer to supplant the T21 and T31 era. First flight was 1961. It worked well in that scene and a lot were sold to clubs who put them to use. The RAF did not buy them however so I was quite keen on making their acquaintance when I re-entered civilian life.

 

 

In typical Slingsby fashion for two seaters (other than the T31) the T49 was very large and heavy although the wing span was slightly less than 17 metres it gave an aura of being bigger.

 

 

A side by side two seater with a single main wheel and a front skid, the aircraft sat nose down with low cockpit sides therefore getting into it was easy – you just sort of stepped in rather than climbed in.

 

 

The cockpit was roomy and the seating slightly reclined so it was comfortable. The large single piece canopy, hinged from the back and gave a panoramic view almost to knee level – bit like sitting at the cinema.

 

 

The controls came to hand easily enough the dominant feature being the centrally mounted airbrake lever that was connected to devastatingly effective air brakes.

 

 

Launching the T49 was always a problem. It took a poor wire launch and required a very healthy tug for aerotow. The machine worked well enough at ridge sites when the wind was blowing but otherwise it was a pain in the neck (and back) as a fast turn around trainer.

 

 

Flying the thing was easy enough but it was heavy and slow in roll and overall gave the impression of being ponderous. Probably ideal in Aussie conditions but not for weak UK conditions where you really have to work for lift most times.

 

 

One had to be careful of teaching aerotow in it as it was quite large enough to totally dominate the tug and a few tug pilots had exciting moments when students were allowed to go too far by the instructor. Approach and landing were fine and no problem.

 

 

The stall was benign and the aircraft would not spin at normal loading. It was therefore not a good basic trainer. In a working environment most of us avoided the thing unless we were detailed to fly it. This was not because there was anything particularly wrong with it as glider per se – but you could not get the work done with it that we had to do.

 

 

T53.

 

 

This two seater saw the A version first fly in 1967 and the B (which became the main production type) in 1968. A C was introduced a little later to give the glider more rudder authority but not many of these were made.

 

 

The type was something of a departure for Slingsby who evidently wanted to progress and ‘modernise’. They did this by coming out with a tandem all-metal monocoque aircraft of mid wing layout and with nose and mainwheels. The wing span was virtually 17 metres and the C had a MTOW of 567 kg (the B was a bit lighter) so it was a fair lump of glider.

 

 

On the other hand, for its size, it was easy enough to move around on the ground and working with one for a full day in a wire launch environment was quite reasonable.

 

 

The aircraft took a very good wire launch indeed and could match the ASK13 in that department but there were some definite shortcomings with the design as a trainer.

 

 

Although the glider flew well and had a nice stable feel it also had a broad chord parallel wing which is most unusual for a sailplane. In turn this generated massive aileron drag and you were constantly working the rudder against the slightest aileron movement.

 

 

I felt the view was too good in terms of the very low cockpit sides giving too much feeling of exposure for a broad range of students in a commercial environment.

 

 

My general summing up was that the machine did not offer much that was new and was no real competition either in working ability or price, to the German production trainers that were now becoming quite refined and were having increasing club impact on UK gliding.

 

 

[Guest pelorus32]

G'day Tony,

 

that post brings back some memories. When the Blanik was not available we would sometimes get the T49 Capstan - colloquially known as The Duck.

 

I couldn't see the point of spending my hard earned pennies on it rather than the Blanik so I developed a method of suddenly vanishing if my turn arrived at the same time as The Duck came to the front of the line - call of nature or some such excuse.

 

It really did have fabulous visibility but that was about all it had going for it - just like sitting in the movies and you could also see the devious b%$$&^ who was usually hidden behind you!!

 

Thanks

 

Mike

 

 

[Guest coaltrain]

Tony,

 

A good, enjoyable read, Keep the posts coming!

 

I always remember the T53 being a very different kettle of fish to fly compared to the K7 and K13 I was flying at the time.

 

 

[nathan_c]

Looking forward to the next one! Keep them coming