School EN-A glider usability for cross country

Every year I read discussions of impotent EN-A school gliders, especially in flats. As a curious mammal I needed to validate it. Fortunately I know well some school owners and agreed to borrow an EN-A certified – UP Ascent 4 (next “School glider”) for some test flights. Not sure how different are other brands.

The weather was generally bad. Few soaring days in strong 8 ms wind. After almost two weeks one average day was forecasted, so with bunch of friends we departed to our popular hill “Ranรก”.

Flying conditions were far from optimal

There was swift SE wind, for this hill a parallel direction. Fortunately the thermic was strong so wind direction near ground was mostly E. The sky was cloudless, with inversion layer in 1300 m. If we somehow manage to get up, the biggest issue is TMA around Karlovy Vary airport, where we will be blown and it is almost unusable 1030 m AMSL on edges, 0 in the center. My friends jumped into a weak thermal and drifted when I had a lunch, as I landed twice before. So in the air I was alone.

The trip was amazing experience, and we managed to travel back from Pilsen (yes, the best beer is brewed in this city) together with all my friends. However this article is meant as comparison.

Last season I flew on EN-C UP Trango X-Race, this year on EN-D UP Meru. All flights in my Advance Lightness 2 harness at around 90 kg total flight weight. I can tell you there are differences ๐Ÿ™‚

Glider parameters

Model Ascent 4 Trango X-Race Meru
Size SM SM SM
For
Student Cross country Competition
Surface area flat (m2) 25,5 23,1 23,4
Surface area projected (m2) 22,2 19,7 20
Flat span (m) 11,1 12,7 12,7
Projected span (m) 8,68 10,2 10,4
Flat aspect ratio 4,8 6,9 6,9
Projected aspect ratio 3,39 5,3 5,3
Chambers/cells 34 68 84
Total line length incl. Brake (m) 312 239 212
Glider weight (kg) 4,4 4,25 5,2
Category LTF/EN A C D
Takeoff weight (kg) 70-95 78-100 90-105
Visual comparison Trango (left) vs. Ascent (right)

Now some description to those numbers:

School glider is comfortable in wild thermals and passive piloting is acceptable. Despite strong conditions I was able to have a snack any time. I did only two small corrections, old habits. While flying Meru few days later in similar conditions I notice my nervous looks to dancing glider, prepared to cut the loose fast.

As a small disadvantage I feel there is no push for active flying. The good is I can focus on strategy, the bad is I do not develop control skills. However at my beginnings, I would choose the first option. 

School glider is slow. On trim speed it is around 4 km/h slower to Trango. During strong wind soaring it was visible. Despite I would not go to such wind after the course, I feel more secure on Trango/Meru as their trim speed is around 4 km/h faster. The speed system on School glider is felt secure and stable. As result I really did not fly behind the ridge, as should be after the course. On the other hand, it increase the speed just around 6 km/h. In strong wind I feel more secure on my Meru where increase is more than 15 km/h. Take numbers as approximate, just from gps without any normalization.

School glider is agile. It can turn on the ear, it can do even a flat turn. It has long brakes so it is required to lean as much as possible and add a long hand on brake. Because reactions are slow, the timing needs to be little in advance. In tight turns the glider loose significantly more height. In comparison to Trango/Meru reacts much faster and tight turns do not loose so much altitude. Also they transform small bubbles to height much more effective. However in small bubbles it is difficult to get up for me even with my experience.

School glider can climb faster. I have no direct comparison but I am noticed this also few years back when moved to higher categories. In strong and narrow thermals I braked quite much both sides and slow speed meant more time in thermal. When dropped out just release outer brake and School glider swiftly turn inside the thermal again. On Trango/Meru this technique is quite difficult and risk of negative spin is high, so I prefer turning on speed but in ultra sharp turns.

The School glider is worse in difficult conditions where thermals are broken and bubbles plentiful but weak. Honestly, it usually means not a good day anyway and it is a fight even with Trango/Meru. A hidden benefit of school glider is that long flight is also a small workout for arms.

School glider is much easier to land. Lower speed and high sink rate near minimal speed meant really precise landings. On Trango it was so so. On Meru I need to be focused at maximal level. And landing with nil wind after a long flight for us older means neccesity of a good legs warm up in the air.

School glider is worse to packing. I used concertina. It has less cells so leading edge is fast, but so many lines means more tangles and more branches in them.

School glider starts easier in strong wind. At beginning I made too little inputs and had some issues but with small practice it was super easy. The cravat is almost impossible to create. On Trango you fight with ears trying to cravat. With Meru you fight with rods in trailing edge which rises easyli themselves and pushing them back is quite a challenge.

School glider’s performance is worse, especially in situations where is beneficial to go on high speed. Low trim and maximal speed limits flying against the wind. For open tracks with wind there is easy to get 100 km in flats I am sure. But bigger triangles are difficult because of limited time/slow speed and once hit a small headwind (>2 ms) in any direction, it would be very very difficult to finish. The often discussed poor glide I did not notice.

The result of my flight was 56 km. A decent flight but in difficult conditions and single day opportunity used. The tracklog is here: https://www.xcontest.org/cesko/prelety/detail:petr.kozisek/15.04.2019/11:19
For comparison, the same day/terrain there were bunch of pilots on high EN-B gliders and they cooperated. I rarely land from 1700 m to ground without hitting any thermal but this day was one of these rare ones. Still, difference was not extreme and all pilots flying alone too landed before me. It would be interesting if we flew together but unfair to make any assumptions.

In summary, the all time question to choose EN-A or EN-B glider after basic course depends on skills and ambitions of pilot. It is sure that at beginning of pg career the limits lies within pilot skills. The high performance gliders are much better in difficult conditions where newbies are not recommended to fly anyway.

Daily score from the same terrain, no better flights in my country that day.

A visual of TMA airspaces. The TMA Prague above take off is FL65 (1980 AMSL). This one is no issue for XC

Thanks to www.pg-shop.cz for lending me the glider.
PS: I am not paid by anyone, nor will compare EN-A gliders in future ๐Ÿ™‚

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