In a recent post I discussed my first cross-country glider adventure using the Schleicher ASK 21 glider model in X-Plane 11. That flight, which was published on my YouTube channel, was principally a ridge soaring task set at Zell am See in the Austrian Alps. This post details and links to another YouTube flight, which is a repeat of that task, but in the FSX Steam Edition simulator.
The YouTube video of this flight is best viewed in HD full screen mode if your Internet service supports it.
My intention in repeating the same task in these two flight simulators was to compare the virtual ridge soaring experiences that could be delivered by both products. To give some validity to this comparison between X-Plane 11 and FSX, I used: the same cross-country task course, the same time and date, near identical weather conditions, and identical glider model types, although the glider models were made by different developers. The only common glider model type available in both of my sims at the time of these comparison flights was the ASK 21 2-seater training glider. This meant using an add-on glider model in FSX. Leaving aside the motorized (self launching) versions, there were two add-on glider models of the ASK 21 available to me in FSX. For this flight I chose to use the Aerosoft ASK 21 rather than the ASK 21 available from Wolfgang Piper’s collection of freeware glider models because I am most familiar with that model from Aerosoft.
To be fair to X-Plane, I have no doubt that if I had compared both sims without any add-ons or plugins, then X-Plane would be streets ahead of FSX in any virtual gliding comparison. However, I am mostly interested in comparing the best possible virtual gliding experiences that these two flight simulators can provide me, including any available add-ons or plugins that I currently use to improve the overall experience.
Bear in mind also that I intend this to be a two part comparison. These first two flights provide a comparison based on a cross-country task in an alpine location where ridge or slope lift is the predominant energy source for the glider. In the second part of this comparison between X-Plane 11 and FSX, I intend to create a cross-country task in a flatland location where only thermal lift is available.
There is a discussion of the flight plan for this task in the YouTube video linked above.
Configuring the Soaring Environment in FSX
Obviously, time and date are the easiest components of the soaring environment to match up in the two simulators. Thus, in FSX, I set these to: 14 July 2016 at 14:00.
Matching FSX weather settings with those used in X-Plane turned out to be more problematic. Initially, I intended to use default FSX manual weather settings in conjunction with the CumulusX! add-on to re-create the soaring environment as near to that used in my X-Plane 11 flight as I could manage. However, I ran into a commonly occurring bug in FSX whereby multiple wind layer settings can be corrupted by the addition of turbulence and/or wind gusts in some layers. This led to failure of wind generation in FSX and thus no ridge lift in my first failed attempt. Moreover, turbulence and wind gusts in default FSX weather seem to be unrealistically abrupt and make the variometer very difficult to read because it does not have a gust filter. To work around these issues, I opted to use the Active Sky 2016 add-on in custom manual weather mode to re-create the weather conditions. Even with the less abrupt wind variation generated by AS2016, the wild excursions of the Total Energy variometer needle on the ASK 21 proved to be difficult to read at times. I seem to recall that the X-Plane ASK 21 had a similar issue with its variometer.
Following are some screenshots of my Active Sky 2016 weather settings.
NOTE: I started by selecting the default Realism Mode in AS2016. I then disabled any AS2016 wind updrafts or downdrafts so that CumulusX! could do its thing without unnecessary interference or augmentation to lift production. I also set wake turbulence to zero because that effect seems too violent and the motion unrealistic for a glider following a tow plane.
This was principally a ridge soaring task, however, I felt that it was both reasonable and realistic to provide some thermal lift, which I hoped might assist with ridge transitions.
It is difficult match thermal conditions between X-Plane and FSX because FSX has the benefit of the CumulusX! add-on with comprehensive user control and documentation, whereas X-Plane provides minimal support for random thermal generation with only a percentage coverage slider and a thermal height slider for user control. I chose to use the default settings for CumulusX!. The default settings in CumulusX! provided a smaller thermal coverage than my chosen setting in X-Plane, but I wanted to provide similar overall thermalling advantage to the task bearing in mind that CumulusX! provides cloud based thermals, which are easier to intercept, whereas X-Plane thermals are invisible “blue” thermals.
Following is a screenshot of my CumulusX! soaring environment settings.
NOTE: The Min and Max Lift Ceiling settings in CumulusX! do not apply for this task because CumulusX! gives preference to any cumulus cloud base setting in FSX. This was set by AS2016 to 10,153 feet.
Results and Conclusions
Ridge lift conditions were remarkably similar between these two flight simulators for this task. This was a surprise to me. I was expecting FSX with the CumulusX! add-on to provide a better ridge soaring experience.
The level of difficulty in completing the task was also much the same in both sims, although I achieved a better average task time in X-Plane. I believe that the faster task time in X-Plane was probably more the result of my mistakes and tactical choices than to any differences in the way these simulators render the task. Also, due to my inexperience with X-Plane, I may have set the thermal conditions in X-Plane a little more advantageous than was needed in my effort to offset any anticipated disadvantage due it being limited to blue thermals only.
Both simulators had convincing flight models for me, although fluidity and dynamic movements seemed noticeably better in X-Plane using X-Camera and HeadShake plugins. I was using Chaseplane and A2A Accufeel add-ons with FSX, but I could not achieve the same level of immersion using the settings that tried for this task.
Sound effects seemed slightly better to me in FSX. X-Plane lacked any sound effects for the spoiler operation. The spoilers should make noticeable clunks when opening and closing and they should create extra drag and rumble noise effects. Modelling of aircraft vibration with the spoilers deployed was absent from both sims. The tyre squeal on a grass landing in X-Plane was awful and unrealistic.
The aerotow launch was definitely more realistic in FSX compared to X-Plane. In X-Plane the tow plane veered off the runway centreline as soon as the ground roll commenced, which I assume was a lack of control over the wind vane effect on the tug aircraft due to the cross-wind component in this task. Also the X-Plane ground roll seemed far too short. Moreover, by default, X-Plane commences the launch automatically as soon as any glider flight loads. It would be much better if there was an option to have the launch manually started after instrument and control checks.
In regards to the alpine scenery around Zell am See, I believe that the X-Plane default scenery and mesh had the edge over FSX with Orbx global textures and Pilot’s Ultimate Mesh. This was mainly due to the apparent stretching of textures in FSX on steep mountain slopes. Also the scenery coloration in X-Plane seemed more convincing to me. River boundaries looked slightly less artificial in X-Plane, but roads seemed to be more unrealistically placed over the terrain mesh than in FSX, although both had problems. Each of the sims had a scenery anomaly. In X-Plane it appeared on the second leg of the task and it looked like a tile seam mismatch. In FSX it appeared on the last leg of the task and it looked like a data issue in the terrain mesh.
The lighting and shadows are noticeably better in X-Plane. There was, however, some annoying flutter in cloud shadows evident in X-Plane. On the other hand, FSX does not even have cloud shadows. CumulusX! has an option for cloud shadows for CumulusX! generated clouds but this option has issues, particularly in alpine areas, and I rarely, if ever, use it.
It would be unfair to compare airport scenery between the sims for this task because X-Plane was using default, but I inadvertently chose a location for this task that included an add-on airport scenery from the Orbx European freeware airport packs.
In my opinion the issues mentioned and any that I may have overlooked are not major. Overall, I am mightily impressed with both simulators and their ability to provide a convincing and entertaining virtual ridge soaring task with the Schleicher ASK 21 model glider. In the case of X-Plane, this is quite surprising to me given that X-Plane does not have a sophisticated soaring environment compared to FSX with the CumulusX! add-on. It will be interesting to see whether both simulators will compare as equally when tested with a flatlands thermalling task. So that is my next intended YouTube project.