LS 10 st

LS10-st in Competition Flying
by Jean-Philippe Leduc

First of all I wish to express my grateful thanks to Holger Back for giving me this wonderful opportunity to fly the new LS10-st in the 2008 belgian championships.

Being a LS addict ( I was owner of a LS7WL, then a LS6 and now a LS8-st) I was particularly delighted to fly the last ship of the long LS family.

Glider assembly
Comparing with our LS8 ST the LS10 assembly procedure is similar except the fitting of the 18 meter extensions which has been made easier through the use of the typical DG type locking pin replacing the tedious locking wheel of the LS8. This is a good choice as it makes the wing extensions assembly much faster and easy.

The LS10 cockpit looks very similar to the LS8 one but a careful inspection shows some improvements: The rudder pedal adjustment system much better positioned, the new DG type integrated bug wipers and the completely new water ballast system design.

This last improvement is significative as DG Flugzeugbau in order to raise the MTOW to 600 kg has designed a structural ballasts system with 3 filling/dumping vents per wing.

By the way these 6 dumping valves provide a very spectacular view of the glider when dumping through the finish line at the end of a task !

But the very clever idea with the ballast system is the design of two separate tail tanks. 

The first tail tank compensates the 4 external wing tanks for CG position stability and the second compensates for the 2 internal wing tanks.

This means that I could maintain a good balance of the glider all through my flights whatever water dumping I had to do during the flights. I think this is a key advantage in competition.

The water ballasts filling procedure is easy and straightforward.

The electric bugwipers are integrated inside the fuselage profile when stowed – a system designed originally for the DG808B and C family. This is easy to use and I had no trouble with the system all through the competition.

This particular LS10 was equipped with solar panels which allowed me to fly all the competition without ever having to reload the glider batteries ! All customers should buy this option as it eliminates all risk of power breakdown in flights even the longest ones !

On board
Taking place inside the narrow but comfortable cockpit makes me feel immediately at home as I find again the well known environment of my LS8 and the other LS gliders I owned before.

Although tall (1m90) I have no difficulty finding a good position in the cockpit.

But it is important to carefully adjust the rudders pedals and the backrest to find a good fit In the cockpit.

I flew my first flights with the backrest installed and then I removed the backrest on the next flights and used the separate headrest provided when flying without backrest. I found this way an ideal position in the glider which provided me a very good feeling of the glider without having to adjust the rudder pedals at their longest position.

All controls are well positioned in order to optimize space in this narrow cockpit.

The flaps controls is ideally positioned (please don’t change it) very easy and relaxing to use.

It also allows an easy visualization of the flaps settings.

A very nice improvement compared to the LS8: the wheel brake control is now triggered at the end of the airbrakes control as on the DG glider serie. This is also a safety improvement as on the LS 8 (and other LS ships) one must avoid forget reduce the rudder pedals distance before landing in order to be able to use the brakes efficiently by depressing both rudder pedals.

In flight
The towing hook is placed in the nose (as on the LS8) which makes the handling very easy during air tow.

Takeoff and air tow are uneventful: handling is very easy during this flight phase. The flaperons are very accurate and very efficient right from the start of the takeoff roll.

After release I was delighted again with the LS10 handling really representative again of the famous “LS touch” with a small reservation though related to the ailerons controls still slightly to heavy. But according DG this defect has been corrected on later LS10 gliders.

The harmony of the controls is very good with a good mix of agility and precision without compromise on the stability on all axes.

Congratulation because with this glider with such a pleasant handling I am pretty convinced that the competitor will get an edge against other pilots because he shall be submitted to a lower fatigue state at the end of long difficult flights.

I immediately observe very interesting flying qualities at low speed. Spiralling at 85 km/h is easy and the trim control is convenient.

In transition flight at high speed I observe that the glider remains nicely stable.

Thanks to the relatively stiff wing I can easily feel the turbulences and the behaviour of the air mass. Nevertheless the comfort on board remains always very good.

The utilisation of the Solo engine is particularly simple and straightforward thanks the well known DEI engine management system.

The expertise of DG Flugzeugbau in engine management for gliders is no longer to demonstrate : using the turbo on the LS10-st is simple and very safe.

Approach and landing with the LS10 poses no problem. The combined usage of the flaps and airbrakes allows for a wide manoeuvring margin in final.

It is moreover not necessary to use the landing flaps setting to achieve a short landing run.

Everybody knows that there are always differences between individual gliders from a same serie: surfaces condition, gap sealings, balance differences, different flap settings.

Therefore I think the best method to evaluate a glider model has to take place in a competition.

Of course pilot qualities also can make a difference but if there are a sufficient number of tasks in a given competition it is possible to gather very interesting informations made through very different flight conditions during a competition.

I must say that this Belgian championship 2008 was a new start in competition for me after 2 years interruption due to a back surgery which made it very difficult for me to sit longer than 4 hours in a cockpit.

I entered therefore the competition with a limited training time but I did not feel disadvantaged very much in this competition because I felt immediately at home in the LS10.

Initially we made a team flying with Louis Dresse flying our LS8-st.

Weather conditions were exceptional with very high average speeds and it soon appeared that it was difficult to remain together during the tasks as above 180 km/h it became very difficult for the LS8 to follow the LS10. He had therefore to reduce speed to limit the altitude difference and this broke the team flying by increasing the distance between the 2 gliders.

Comparing the LS10 to the Ventus 2Cx and Lak 17 present at the competition I observed very small differences in weak conditions but on long transitions at high speed (above 150 km/h) the LS10 displayed a small edge to its competitors.

This small advantage becoming more significative above 190 km/h.

These observations were confirmed on the fastest task of the competition that I won with an average speed of 124 km/h on a 496 km distance.

It must be said that for safety reason MTOW were limited at 500 kg in this competition . As a consequence I could not compare the LS10 at its max wing loading against the Ventus 2 cx and LAK17 also at their max wing loading also. But still with this limited wing loading which was in my case lower than the wing loading of the Ventus 2 and Lak 17 I still won this task.

After emptying the water at the end of some tasks I observed that the glider climbs as well in weak thermals than other gliders without engine.

I think that the weight of the turbo does not represent a handicap for the LS10-st.

I finished the competition at the fifth place. This average result is due to a too late start on the first task with a engine outlanding which costed me the podium.

The LS10-st is a well born glider and I am sure a very successful design.

I found again the handling qualities that I am used with all LS gliders.

If the control heaviness is improved on production ships (which is confirmed to be the case by DG) I am convinced that the glider shall be a top winner in next years as I think its performance is slightly better than its other 18 m.

I also appreciated the easiness of operation, quality of fabrication and the very safe and comfortable engine operation.