This simulator really captures the feeling of RC gliding in a mountain updraft.

There is a small amount of setup to get the most out of it, here is a Rough Guide.

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Rough setup guide.

Download the game
Download a mountain from the Sceneries section on the left of the webpage ( this is a good start : Col des Faïsses-F3F -- http://joel.lienard.free.fr/crrcsim/faisses2.zip )
Unzip that scenery data in to the scenery directory of the game
Start the game

Press Esc , choose Options then Location and select the mountain

Launch a glider and float in the updraft and thermals.

Middle mouse restarts the simulation, left and right mouse unpauses and pauses . Scroll wheel controls the throttle on powered aircraft . Esc -> Help -> Keys has more .

There are many other gliders , powered aircraft and 2 helicopters . ( The Crossfire or Supra is a decent starting glider )

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The new website for ccrcsim is : https://sourceforge.net/apps/mediawiki/crrcsim

Ok, an alien slaughter is always funny. But found it worse than the original game, and the sound still crashes with every berserk shooting.

Twitch-based, focused on combat, realistic physics within boundaries, with many layers. You can do anything, or play a role as soldier, nationalist, privateer, pirate, trader, hauler, miner... or capship builder for marathon runners...

Fast gameplay, cheap subs, small but active community. If you like space sims, this is a good choice.

Vendetta compares to EVE as solitaire compares to a screensaver...

Wow! As a declared FAN of reimagined Battlestar Gallactica, I downloaded the fresh release of Diaspora and am amazed! Perfect Visuals, good gameplay.

Basically, it is Freespace2 SCP in BSG universe. Early release, few content and lots of promisses.
FRED can be used, so any FS2/Babylon5 coder will feel at home.

Running on Linux, boring to compile, but works fine after required -dev libs are installed.

Worth try!