AVSIM Commercial FSX Aircraft Review

Discus Glider X

Product Information

Publisher: Aerosoft

Description: The first commercial glider add-on for Microsoft Flight Sim X.

Download Size:
115 MB

Download / CD
Simulation Type:
FSX - SP2 or Acceleration
Reviewed by: David Pike AVSIM Staff Reviewer - August 20, 2010


Gliding, sometimes known as soaring, could be described as the purest form of flight.  It certainly is one of the most graceful.  Glider pilots learn to use the currents of the atmosphere, finding areas of rising air to stay aloft.  These include columns of warm air that rise to produce "thermals", or the flow of wind up and over ridges that allow pilots to fly parallel to them, almost like a surfer riding a wave.  Using these forms of lift, modern glider pilots can often attain altitudes and speeds that would make many Cessna pilots green with envy.

Despite this, Microsoft Flight Simulator has not always catered well for the glider pilot.  The latest version of MSFS has at least given us the opportunity to hitch a lift behind a tow-plane, but the selection of aircraft has still been limited.  Until now, that is.

In Discus X, Aerosoft has created the very first commercial glider add-on for Microsoft Flight Simulator.  The Discus is a high performance glider designed by the Schempp-Hirth company in Germany in the 1980s, and was the first sailplane to feature the distinctive swept-back leading edge that reduces drag.  During the late 80s, the Discus was a world beater, winning the World Championships three times.  Although it might have been eclipsed more recently by newer machines, it remains a competitive aircraft and popular with gliding clubs around the world.

Will this package be the answer that glider pilots have waited for?  Could be...

Test System

Computer Specs

AMD Phenom Triple Core 2.10 GHZ Processor operating Vista Home Premium 64 Bit
4.0 GB RAM
NVIDIA Geforce 9500 GS Graphics Card
Saitek X52 Pro Controller with Saitek Pro Flight Rudder Pedals
FSX with Acceleration expansion

Flying Time:
17 hours

Installation and Documentation

Obtaining the Discus X from the Aerosoft website was very simple.  Once ordered, the website provides a link to download the installer, which weighs in at about 115 Mb.  This is then activated using the code emailed after purchase.

The installer is responsible for setting up not only the aircraft itself, but also the WinchX! utility that is packaged with it.  It is important during the installation process that you follow the instructions carefully, otherwise WinchX will not work properly.  Having said that, the process is straightforward and quick, and within 10 minutes of downloading the product I was ready to start FSX.

One more word of caution:  when starting FSX for the first time after installing the Discus, WinchX! will also try to start.  FSX will ask you if you trust this software, to which you must click "yes" to enjoy the functions of this brilliant little tool.

The documentation that is supplied with the software is plentiful and comprehensive.  Firstly, Aerosoft has provided their own manual that includes a history of the aircraft, the recommended FSX settings, and the details of the cockpit instrumentation.  I liked this manual enormously, and found it easy to read and very informative.

In addition, Aerosoft have included the following (in both English and German):

  • The Pilot's Operating Manual for the real-world Discus
  • The manufacturer's guide for the C4 Competition gauge
  • The user guide for the WinchX! utility that is included with the aircraft. 

We’ll cover the features of these last two later in the review, but Aerosoft should be applauded for the quality of the information provided.

External Model

The external model captures the graceful lines of the real aircraft wonderfully.  There are several variations provided, each of which offers a different wing layout - the span varies and some are fitted with drag-reducing winglets. The model is animated, with the undercarriage, control surfaces and spoilers recreated faithfully.  The wings also flex in response to the environment - try watching a hard landing from the spot view and see the wingtips bounce alarmingly!  The pilot is modelled well with very nice animation, looking every inch the aviator in sunglasses and a soft hat.

The Discus B

In addition to the conventional glider, Aerosoft has included two powered options, the Discus BT and BM.  The BT model is fitted with a small engine that will keep you in the air between thermals, but is not powerful enough to take off.  In contrast, the BM version is a true self-launching glider with a motor big enough to take off and climb to altitude.  In both cases, the motor is hidden inside the fuselage behind the pilot and unfolds using controls in the virtual cockpit.  The engine animations are very smooth, and the motors (different for each model) are nicely detailed when extended.

The Discus BM self-launching glider The Discus BT with sustainer engine

Modern gliders are designed to have very smooth surfaces to reduce drag, so do not expect the external textures to be too detailed.  The wings, fuselage and tail are all white, with a few of the models offering a splash of colour at the nose and wingtips.  The textures show the registration of the glider, and the competition number on the tail.  This is used to identify individual gliders from the ground during competitions.

It would have been nice to see a few more nationalities represented.  The schemes mainly have German registrations with a single British example, but this is a small criticism.  The texturing of the details - the cockpit, pilot and the engines of the powered version - are all very good.

Compared to the frame rate of the MS default glider, I saw no dip in performance in the external views, and the textures load with no delay.  All round, a very solid performance.

The Cockpit

The virtual cockpit

The Discus is not supplied with a 2D panel, so all of your time will be spent in the virtual cockpit.  Aerosoft has done an excellent job with the panel which is well laid out with some surprisingly sophisticated instruments.  Each model is equipped with an airspeed indicator, an altimeter and at least one vario.  A vario (or variometer) is a highly sensitive vertical speed indicator with some special features.

Unpowered gliders are subject to gravity and can only gain altitude when the air around them is rising faster than the glider's rate of descent.  The vario is designed to take the sink rate of the glider into account, and shows when the external air mass is rising or sinking - vital information for the long-distance glider pilot.

Also included is an instrument called the C4 Competition.  This device combines the functions of a vario, flight computer and altimeter, and Aerosoft has worked hard to replicate the exact functions of the real world instrument.  In fact, rather than create a user manual, Aerosoft has simply supplied the real-world documentation from the manufacturer.  A detailed description of all functions of the C4 would take too long, and I heartily recommend that you read the user guide carefully.

Briefly, the C4 is designed to maximise the glider's speed over the ground during a cross country flight.  It takes into account the strength of the thermals that the pilot can use, and recommends the speed that the pilot should fly to reach the next thermal.  If you think gliders are basic, this may change your mind!

A close up of the panel showing the C4 Competition Gauge

The GPS is mounted to the right of the main instruments and is designed to replicate the PDA-type device that is popular with glider pilots.  When in use, it works in a similar way to the default GPS showing course, speed and altitude.  I noticed a slight drop in the frame rate from 35 fps to around 32 fps while the GPS was activated, and the display stutters slightly.

The overall effect of the cockpit is very pleasing.  The textures of the instruments are crisp, even when viewed closely, and the gauges are very smooth.  The body of the pilot is visible when using the virtual cockpit - you can see his feet on the rudder pedals and his hand on the control column.  If this is not to your taste, a simple click of the mouse removes him.  A nice touch.

One final feature deserves comment.  Gliders are not equipped with turn and slip gauges – they use a piece of string!  The yaw string is affixed to the outside of the canopy, directly in the pilot’s line of sight, and shows whether the aircraft is yawing left or right.  To keep the aircraft coordinated, just keep the string horizontal against the canopy.  The Discus is equipped with a yaw string which works exactly as in the real world glider.


Flight without power doesn’t mean flight without sound, and the Discus demonstrates this well.  The package comes with over 100 custom-made sounds, controlled by a special gauge which responds to the FSX environment.   From the whistle of the air flowing around the cockpit to the rumble of the wheel over a rough field, the sounds are handled exceptionally well.  You can even hear the creaking of the wings as you fly through turbulence.

The one exception to the subtlety of the sounds can be experienced when the engines of the BT and BM models are started.   The manual warns that both engines are extremely noisy, and in use they do sound like a buzz-saw just inches behind the pilot’s head.  It definitely makes you appreciate the quiet once they are turned off!

Getting Into The Air

Gliders in MSFS have always struggled with the task of getting off the ground.  As mentioned in the introduction, FSX now provides a tow-plane to solve this problem.  However, Aerosoft has provided an alternative by partnering with Peter Lürkens, a German developer who has created a wonderful little piece of software called WinchX.  This is designed to simulate the standard winch launching of gliders, and allows the user to select the height and speed of the tow.

A winch launch

To use WinchX, create a flight and press Shift-Y when you are sitting at the end of the runway.  The programme will run through a short procedure, all narrated by a virtual pilot with a distinguished German accent.  The tow cable will appear just to the left of your aircraft.  At the command "Take up slack", the cable will be pulled tight, and your glider will move forward a little in response.   The next command will be "All out", and you are off!  At the correct airspeed, pull back on the stick and fly the correct attitude for your climb.  Once you have reached your selected altitude, release the cable.  When the cable is released, you will see a small parachute descend slowly to the ground - that is the end of the tow cable.  It even works with the default DG-808S glider.

I cannot describe how much the addition of WinchX has enhanced this package!  I have found myself flying a whole series of 10-minute flights just to try the launch again.  Aerosoft recommends another piece of software produced by Peter Lürkens called CumulusX which creates thermals randomly, each with its own cumulus cloud.  This add-on is not provided with the Discus, but can be downloaded for free from Peter's website.  Details are in the Discus manual, and for real soaring I thoroughly recommend it.

In Flight

Circling in a thermal

Once aloft, the controls are very responsive and will reward a delicate touch.  It is important to coordinate aileron and rudder inputs - possibly more than in a powered aircraft - but once you get the hang of it, flying the Discus is easy.  Circling within a thermal requires quite a steep bank angle to remain within the rising air, and attention must be paid to the airspeed.  The stall speed of a fully laden Discus B is 37 knots, but this increases remarkably at high bank angles.  Stalling can lead to a noticeable drop of the wing, but recovery is quite straightforward, and the real-world manual gives clear instructions on the best procedure to use.

At the other end of the flight envelope, high speed flight is very stable.  I found that when flying in good ridge lift, it is actually easy to over-speed the aircraft while still climbing, so care is needed.  With the addition of the CumulusX software it is possible to conduct long cross-country flights, and this is where the C4 Competition gauge comes into play as it gives clear guidance on the speed to fly between thermals.  Several times I found my heart start to beat a little quicker as I struggled to find the next thermal before reaching the ground.  This is a very addictive experience!

Turning finals with spoilers deployed

Using the payload system, it is possible to add ballast to the Discus to optimise performance for the weather.  A heavier glider will fly faster over the ground, but will require stronger thermals to gain altitude.  In contrast, a lighter glider can take advantage of weaker thermals but will fly more slowly between them.  Therefore, competition glider pilots add water ballast to suit the conditions of the day.  The Aerosoft Discus is no exception and the ballast has a real effect on performance.

Landing will require you to get to grips with the spoilers.  These are very powerful airbrakes that extend from the upper surface of the wing which both slow the aircraft and reduce the amount of lift that the wing generates.   In contrast with some other aircraft, the spoilers on the Discus are variable.  If you have one, it is recommended that you assign control of the spoilers to a throttle quadrant.  This will allow very fine control of the airspeed on the approach and with practice you will find that you can place the Discus very precisely on the runway.

Landing is easier than it looks

The engines of the BT and BM models take a little more getting used to.  To extend the engine and get it running is quite simple, and the manual includes checklists for you to use.  All of the controls and instruments are found in the virtual cockpit, making the panel a little bit more complex.  The key point to remember is that the engine sits high above the fuselage, and it has a marked effect on the aircraft.  This is especially true of the BM model when you are trying to take off.  Add power too quickly and the nose will pitch down.  Delicate use of the throttle is the order of the day, and don't expect a short take off.   Getting it right is very satisfying, and once aloft with the engine stowed away, the BM becomes a glider once again.


The Discus is the first commercial glider add-on ever produced in the history of Microsoft Flight Simulator, and I believe that it has set a very high standard for those that hopefully will follow.  A superbly created aircraft, the addition of the WinchX and CumulusX add-ons make this a complete package that will transform the way FSX handles gliding.

The accuracy of the flight model combined with the vast amount of documentation provided means that soaring enthusiasts can finally use FSX as a serious gliding simulator, and maybe even as a trainer.  The Discus is certainly good enough to teach pilots competition tactics and how to make speed-to-fly calculations.  Pilots who enjoy high-tech systems will find the C4 Competition gauge is complex enough to keep them entertained for hours.  At the same time, the more casual simmer should not be scared of the complexity of the systems or information provided with the Discus.  The aircraft itself is wonderfully rewarding to fly, whether using the winch, tow-plane or getting to grips with the self launching BM model.

I find it hard to say anything negative about the Discus.  It would have been nice to see more variation in the nationalities represented by the textures, and the stuttering of the display when using the GPS can be distracting.  However, all other aspects of the aircraft are so good that these minor complaints are quickly put into perspective.

I have been thoroughly impressed with the Discus.  With the different models, extensive documentation and the WinchX utility, this package represents superb value for money.  I will be sending my wish list to Aerosoft in the hope that they will be making more gliders...


What I Like About Discus X

  • Very impressive flight model
  • Great virtual cockpit
  • Complete set of documentation covering the aircraft, avionics and controls
  • Winch launching with the Winch X utility – enormous fun
  • The subtle sounds


What I Don't Like About Discus X

  • I can’t find anything to dislike in this great package!



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The review above is a subjective assessment of the product by the author. There is no connection between the producer and the reviewer, and we feel this review is unbiased and truly reflects the performance of the product in the simming environment. This disclaimer is posted here in order to provide you with background information on the reviewer and any connections that may exist between him/her and the contributing party.

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