Down Memory Lane - From the Log Books #22

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COMPETITION CLASSES.

 

 

The classes that have steadily evolved to control competition flying have had considerable benefit in steering technical development but equally ensured (or tried to ensure) that a broader slice of the gliding community could compete effectively and so have the stimulus to become more proficient pilots. Much the same principles applied to National and World records.

 

 

That was the theory at least but human beings are strange cattle and especially so when it comes to “Winning”. Some people just have to win no matter the cost and have the money to indulge themselves.

 

 

The effects of this may be seen in many sports that have genuinely tried controls to keep valid competition affordable. In motor sport Formula Ford gave affordable open wheel racing for people who could never get into Forumla 1. Go Karts made motor racing accessible to just about anybody. But there are always plenty of ways that things can be improved if you have the money to do so. This may not be simply money itself but access to skilled engineering and workshops that produce something that will give the extra 5% edge that enables you to win.

 

 

Common sense prevailed in some areas. A good example was the abolition of the World Endurance record when it became very obvious that it was proving nothing about gliding but simply how long a pilot could stay awake and after a couple of days or so aloft pilots were killing themselves by falling asleep.

 

 

But in those heady pre-war days of rapid and massive development, the situation became equally obvious who was going to win a competition providing the pilot did not break something! Putting the latest 25 or 30 metre span monster on the line with 15 and 18 metre competition was the equivalent of putting an eagle against a flock of domestic chooks for a flying competition amongst the birds!

 

 

Nobody wanted to put the brakes on the super ships because too much about new methods of soaring was being learnt from them. At the same time, while it was appreciated that the wealthy were going to inherit the sky, there had to be something else for the ‘masses’

 

 

The first attempt was a ‘single design’ competition with the intent of pitting pilot skill against pilot skill and everyone using the same glider type. The glider type was defined as not exceeding 15 metre wing span and a few other constraints that would make it broadly affordable. That was OK but itself would inhibit development of that class into better performing aircraft.

 

 

So out of all this emerged two distinct classes for competition:

 

 

Open (or Unlimited) Class. This would leave development open ended and enable the trailblazing super ship to continue pushing the envelope. You could have what you wanted short of an engine!

 

 

Standard Class. This was no longer restricted to a single type but rather a single ‘template’ of constraints the glider type had to meet in order to keep it affordable. At the same time this was pushing the design envelope in a different way by wringing more performance out of those constraints. In simple terms the Standard Class glider had to be no more than 15 metres, plain wing (no flaps) and fixed undercarriage. There was an additional constraint that the glider had to have terminal velocity speed limiting airbrakes that would keep it within it’s design Vne in a vertical dive. This would allow the glider to cloud fly safely.

 

 

Advent of Glass.

 

 

The Open/Standard Classes worked well enough for a long time and were immediately extended to encompass record flying that also began being ruled by glider classes. But the introduction of the glass glider upset the apple cart something terrible.

 

 

Steadily the accent on gliding had evolved into high speed, longer and longer distance, closed circuits. The days of the ‘downwind dash’ for ultimate distance while not yet over were being controlled by how far gliders could now go. You needed a short holiday to get them back by trailer. This hits the giddy limit when you have gliders crossing the Mediterranean from Europe to North Africa!

 

 

Development in wing section design saw the glass machines with very shallow sections that enabled them to return high glide angles at high speed but still be efficient for low speed soaring. The depth of the wing section did not leave enough room for terminal velocity airbrakes.

 

 

So the Standard Class rules were changed to airbrakes constraining the glider to Vne in a 45 degree dive. In the broad scene this was not of much moment as increasingly countries were prohibiting cloud flying anyway. What the gliding world did see was the immediate introduction of top paddle only airbrakes – that also gave a more efficiently sealed wing.

 

 

Along with this was pressure from users who may only fly in a handful of competitions per year but wanted the best out of the new technology for their personal flying all year around. The fixed undercarriage had now become (proportionately) a very high drag item and people wanted retracting undercarriages as standard. So the Standard Class rules were also changed to accommodate retracting gear.

 

 

The Eternal Gliding Paradox.

 

 

For soaring machines to work really well they have to have two totally opposing attributes. They must be capable of slow speed circling flight virtually at the stall yet be fully controllable. At the same time they have to be able to fly slowly even at high wing loading to be able to land them in confined areas plus have adequate approach aids to tame high glide angles.

 

 

The other factor is the need to be able to get the maximum glide angle at the highest possible speed and a high flying weight which will give penetration.

 

 

One way of doing this is water ballast that allows you to fly heavy and moves your glide angle up the speed range to go places, or fly light for slow speed soaring. The downside is that it is a switch. Once you have dumped the ballast in order to stay up then you cannot get it back so you will lose straight line gliding performance and speed.

 

 

The other alternative is to change the shape of your wing so that it can do the high and low speed tasks. Flaps do this so you need camber changing flaps – but there are two aspects to these as well.

 

 

Drooping the flaps increases the camber, lowers the stall speed and enables slower thermalling airspeeds. Once the flaps are back to neutral you then run into the brick wall of your wing angle of incidence – which is fixed – or is it?

 

 

The main function of the wing A of I is to ensure that the aircraft can alight in the desired manner with the wheels making ground contact a fraction above the stall. This provides the shortest landing run possible.

 

 

The downside is that in flying as you increase airspeed you reduce angle of attack and the nose is steadily lowering. The nose-down fuselage therefore creates a lot of drag – you need to keep it aligned with the airflow to get best high speed glide angles.

 

 

Having flaps that can be placed at negative (or reflex) settings enables you to change your effective wing incidence, keep the fuselage aligned with the airflow, and thus achieve much better high speed glide angles. A multi purpose flap system is therefore highly desirable.

 

 

The Racing Class. The Open Class could have flap systems as a matter of course plus variable geometry on wing area and/or wing span if it could contrive the systems and afford them. The Standard Class was fixed by what it could have. But at the same time Standard Class gliders, via design technology advances, were already matching the performance of the super ships of only a few years previously but could not compete in Open Class with the latest super ships.

 

 

The result was obvious – there was no reason to inhibit the shorter span aircraft just by a competition class but a new competition class was needed to fill demand, create a broad enough market and stimulate even more development.

 

 

So the 15 metre racing class was introduced and we saw types such as the ASW20, Discus and Mini-Nimbus appear. In my view the appearance of this class consolidated all that was best in decades of development. These machines have massive performance, are small enough to be practical to hangar and handle and, as they steadily devalue on the second hand market, will become the future backbone of club and low level private ownership years into the future.

 

 

They also bring with them problems that are more psychological in nature due to changing times and expectations. I will have more to say about that in a later part to this series – and it will be as harsh as it is practical because the performance that has been striven for, achieved and should have fully consolidated gliding – has in my view contributed to the enroaching demise of the gliding movement.

 

 

Consequences of the ‘Glass Explosion’.

 

 

The consequences, across the 1970s and 1980s, of the instant scrabble by existing and new manufacturers to gain a foothold in the new market saw a huge variety of types emerge and be steadily refined.

 

 

At the same time this was happening a great many earlier gliders, if not actually made redundant which they were in competition terms, did make them more accessible to private owners and clubs. There were a lot of gliders about and the gliding world was blossoming. So what to do about that?

 

 

This challenge was met by inventing a new competition class that would put competition flying within reach of just about anybody and they could have fun by participating.

 

 

The Sports Class. This was designed to round up just about anything – you could fly what you wanted. The control was a handicap system which (from memory) used the Ka6 as the datum glider. The class was aimed at inter-club, regional and national competition.

 

 

If you had a lesser performance machine then your handicap put you positive. If you had a higher performance machine then your handicap was penalised. The noble objective was to make everyone equal. Handicap lists were published so that you could work out where you stood.

 

 

It is difficult making everybody equal! Handicapping works evenly if everyone finishes a task or nobody finishes a task. In the middle it may be a different matter. If you and your three mates flying 35-38:1 glide angle machines get home against the rest of the pack flying 24:1 gliders then it becomes a speed race. But the glide angle of you and your mates enabled you to reach that last thermal to get you in. The rest of the pack are all sitting in paddocks because they could not reach it!

 

 

No matter. The Sports Class did a great deal of good and in addition prompted manufacturers to produce Sports Class machines. These in turn became very affordable middle of the fleet gliders for large clubs and top of the fleet for small clubs.

 

 

Round Up.

 

 

The steady evolution of competition classes in my opinion was both a stabilising influence on gliding whilst also being a focussed incentive for development in different areas. I am no competition pilot and have never pretended to be. I have flown in a few but that was mainly to get out the two seaters.

 

 

I guess that I simply lack the ‘killer instinct’ to prove myself better than somebody else. As always in flying my satisfaction has ever been taking a student into a competent pilot, then turning my back on them knowing that they would be safe. I have never needed more.

 

 

Next Time.

 

 

I suppose that I had better get on with production glass single seaters but that will be a bit messy because it was not just glass there were a number of contenders and ideas floating around as well. I will ponder on it.