Wednesday, October 31, 2012

Review of Flightgear

A free flight simulator, being developed by volunteers on the Internet.


How I stumbled upon this system

My friend tried Microsoft Flight from Steam, it looked cool and got our interest ignited about flying planes. It seemed pretty cool at first, being a successor to MS Flight Sim X. It soon became clear though that it had been remade to cater to more casual gamers, not the hardcore flight simmers. Furthermore we found out that Microsoft had cancelled the game, and same with FSX.

I looked around for other sims, and found X-Plane, which was even cooler in many respects than FSX, it was way to costly though, and the addon community, was not as big as it had been for FSX. Next I found Flight Pro Sim, and checking out info on it, I discovered that it was a rebranding of something called Flightgear, which is an open-source free flightsim for Unix, Linux, Mac and Windows. And after having spent some time in the software development business, I am a fan of open-source. That I had to try.

Oh btw, my Flight sim experience is limited. I did Fighting Falcon on Commodore 64, and a couple more on that computer I cannot remember. I have played WWII Online for some years, which FDM is kinda similar to YASim, not a great pilot though and winning in dogfight or even hitting my ground targets was far between, spent most time shooting down planes with AAA.

My setup

OS: Windows 7
Graphics card: Geforce 550 GTX Ti
CPU: 2.2 GHz AMD Phenom 9500 Quad Core
RAM: 8 GB, 800Hz
Sound-card: Creative Gamer Xtreme
Joystick: Logitech Freedom 2.4


The installer was 650MB. It supports 64 bit, and that is the version I will be reviewing.
I also installed an additional aircrafts package (415 planes), and a scenery and airports (20,000!) package for the whole world. Yeah, pretty cool eh? X-Plane do not support the whole world btw., it does not have the upper and lower extremes of the globe.

Instead of downloading the scenery and airports for the whole world, Flightgear has support for downloading it while you fly, which is a nice feature if your download speed is limited and you don't want to spend a week downloading the full package.

The terrain and airports is not overly detailed, I suspect on purpose for ordinary computers to be able to get a decent frame-rate. More detailed versions of various airports and surroundings is available for download though. I have not tested any of those yet, as my setup probably would not be able to run it anyway.

The launcher

Starting up the sim, I get get a rather ugly window, which I would have expected to see in some sort of advanced settings page. That got me a little worried that this was a sim made by programmers for programmers, which was not what I was hoping for. Anyway I had spent some time downloading this stuff, so I pushed myself to continue. This first page had some folder settings, to which I had to add the 2 packages I had downloaded.

Selecting aircrafts

Next page was a list of aircrafts, there was military, airliners, small planes, zeppelins, space-crafts, helicopters and hot air balloons. Even the Wright Brothers first plane was there. I got impressed by that list, still is, very impressed.

Now its a big list, and it could using some sorting options, there is none, and to make things worse, some aircraft is listed by its name and some by manufacturer. This still annoys me after 3 days of using it. In a window next to the list it shows the selected aircraft in 3D, when looking down the list for interesting stuff to fly, each 3D preview takes way too long to load though, and it took less than a minute for me to turn that off. When the preview option is switched off, it does not show a 2D image of the plane, which would have been nice though.

It also shows a rating, for flight model, systems, cockpit and visual model. Still no idea how that works though, is the rating for completeness or correctness? Some aircrafts have a cockpit and system rating of 4/5 stars, but only half the buttons and switches in the cockpit are interactive, so I am guessing its correctness. Most aircrafts are not rated though, as a newcomer to this sim I got to admit, I kinda ignore the planes that does not have a rating, unless I know of the plane in real life and it has a big coolness factor.

The aircrafts also have a status for how far in the development process it is. I have seen unknown, experimental, alpha, beta, development, early production, advanced production, release candidate, front page release. Again, a sorting option would have been nice here. Although the list is impressively large and diverse, most of the aircrafts seem to be unknown, alpha or beta.

I would rather have it as it is though, than the developer team, requiring a certain status or rating for a craft to be included in the list.

I like having lots of buttons and handles to push, so looking at the list for big airliners I found two types with a high rating, Airbus 380 and Boeing 777, that is what I am going to fly I thought, but hold on, I then found out that there are even more community made crafts available on various websites, called hangars. I found one unrated among those that I will be using for this review, the Boeing 787-8, I have spent more time in 777-200ER these last 3 days, but the 787 seems much more complete and I am sure it would get a higher rating had the makers decided to give it one. I downloaded the very latest version of it.

Selecting take-off location

Next page was a list of airports along with their ICAO codes. This page was much better than the aircraft select page. It had sorting option, and search. The search has a big problem though, if I search for London Gatwick it wont show up, seems to be because the search engine differs between capital and non-capital letters. For this review I will be using that EGKK London Gatwick though, it look decent, but is not overly hard on my frame-rate. On the website and forums there are suggestions to various airports and areas that is nicely made. Since the whole earth is supported most of it is auto-generated terrain, some places is more nice to the eyes than others.

After selecting the airport, you can select which runway or parking position you want to start at. You can even select to start on an aircraft carrier, have not tried that though. This page is not fancy looking like a commercial product, but its by far the best page of the launcher.

Final launcher page

Again a unpolished page with too many options, that in my opinion should have been put in a settings dialog. At the top some display options. I want to fly in 4:3 full-screen 1280x960, that option wasn't even on the list. I managed to find some properties file in the installation, where I could enter it though, and that works fine, but issues like this is surely going to scare many people away from trying this sim. I think most want a complex sim flying, not editing xml files, which you can just as well get used to btw., since you probably want to map functions to your input gear, like joystick, and that's not even possible in the user-interface, with luck it will auto-detect your input device(s) and assign some sensible functions to the buttons, if not, go look for that xml file. Luckily my joystick was detected, but I still got no idea what the buttons are assigned to, so I don't touch them. I should mention though that a user-interface for assigning input functions are in development, better late than never I guess, but it makes me worry about the priorities of the project, since it has taken 15 years to decide to make such a thing.

There are many more options on the page, one even require inside knowledge of 3D programming to know what means, specular highlight, I was lucky I have spent some years doing just that and quickly turned it on. Some informative mouse-over tooltips would go a long way, to not scare people away from un-installing this sim. Skilled or not, the developers of this sim sure could use some tips on user friendlyness. After having used this sim for some days now, I have gotten used to it though, but the average person, would probably be looking at coughing up with the money to get X-Plane at this point. Is also the impression I got from various comparative reviews of the two sims. But then again, people that like to fly probably also like to read manuals, and what the UI lacks in information, the manual is packed with, and rather well written. If by this point you have the impression that this sim is kinda amateurish, you will get some respect for its features, if you decide to glean the manual, trust me on this.

Anyway this page also has a advanced settings and I have found some nice stuff in there, like ability to change properties like enabling anti-aliasing and disabling mouse controlled flying. Had to look on the forums to get an idea how to set those though. Very cool stuff like getting realtime weather information, so that wherever you fly in the world, the weather with mimic how it really is there right now. Awesome feature.

Just to mention some other features, multi screen support, multi-player support, multi-player co-pilot (on handful of planes), sophisticated flight-models (yes plural intended, the makers of an aircraft can choose which to use), interactive cockpit (using mouse to click on a button instead of remembering a keyboard binding, the degree to how much this is implemented is varies among the aircrafts though).

Okay, enough talk about the launcher, lets start it up.


I actually had some trouble starting up the 787 Dreamliner, but that's a good thing, being a sim I would have been disappointed if I only had to throttle up and pull the joystick back to get airborne. I had managed to start the 777, and after a while I also got this baby into the air. Some planes have an auto-start feature, but its not so much fun. Exploring the cockpit I found some check-lists in one of the panels, this was awesome, and I could now start the plane the proper way. Some planes have check-list in the menu, and a dialog will pop up, but this was much cooler. Some planes, like the Cessna even has a tutorial, with an add-on its even possible to get it to speak, on windows it requires installation of Cygwin though, and I spent too many years using that, would rather not install it.

Apropos speaking, one of the first things you will notice is the voices on the radio, I guess its control-tower and aircraft communications. It sound really really cool, and after using this sim for some days, it still does not get repetitive. You can also send some messages to the tower,  haven't gotten any response yet though, maybe I need to tune the radios or something or its not implemented.

You can also get AI traffic, it works pretty cool around airports, planes taxiing etc. I switched it off though, it made too big a drop in my frame-rate.

Since it mainly a civilian sim, you have to install add-ons, if you want to be able to shoot, or drop bombs etc. You are also able to 'cheat' and change the view to outside the plane, which enables you to enjoy the view or take some great screen-shots. You can also enable a head-up-display, which shows when looking from outside, and also when not looking forward in the cockpit. The 787 has a build in HUD though that can be activated by clicking on it, and is more to my taste.

About options, the menu when in the plane has also a lot of options, some specific to the plane. Which is cool, I like options. Most of them are saved so that next time you fly, they will still be in effect. Example of a cool option is ability to select Livery, its the painting of the plane, most planes come with a handful, and more can be downloaded from the website, or from a community hangar website. For some planes like the F-16 its more than just paint though, the livery determines the type of F-16 and the load-out. Very cool, but I would have wished an option to select the livery in the launcher.

The sounds are great for most planes I tried, but some like the DR 400, is simply stunning in that regard. Since the sim take a lot of CPU power with nice setting enabled, I would like to use hardware accelerated sounds. Luckily this is supported in two ways when running on Windows 7. The first is DirectSound, which by itself cannot do accelerated in windows 7 or Vista though, but by using Creatives ALchemy it can be HW enabled in these windows versions, on Win XP it works out of the box, as long as you have a sound-card that supports it. The second option is OpenAL, which bypasses windows sound system, and is HW accelerated even in win 7 and vista.

When looking out the window the view is quite pleasing, not on par with X-Plane though, but pretty nice, especially after tweaking the options. The cockpits of most planes I tried also looks real good. The cockpit in the 787 has about 80% of the controls interactive, by using the mouse. Many planes also has a 2D cockpit, but I feel its major flawed, considering it only shows up, when you are in the pilot view and reset your view to forward, if you move the view by a single degree, the 2D cockpit vanishes until you reset the view again, would also be nice to be able to have the 2D cockpit when you look at the plane from outside. When looking around in the cockpit, and other views, with the mouse you and zoom in and out, and use left button, middle button and mouse wheel to interact with controls. The only essential control in the 787 I could not find was the parking brake, but that's probably cause I do not know where it is, so I have to use keyboard to use it.

The 787 has an autopilot, as do most airliners I tried, it works rather well, you can pre-plan a route into the planes system and it will fly the plane for you, some planes will even land also. Hasn't gotten that to work yet, but that more a problem with me than the planes I suspect. The 787 has some videos on Youtube, made by the makers of the plane, detailing different aspects and features of it. I.e. the fly-by-wire system. As far as I understand though, its the only plane in Flightgear that has fly-by-wire.

The menu also offers a map, if you programmed the route into the plane, it will show that also. It does not show any terrain though. But there is a little program called Atlas that can be run alongside the sim, on same computer or on another computer. It will show your plane and the path you have flown, on top of a satellite picture of the terrain. It will also show airports and information about them. Very cool.

I really like to fly in this sim, the sims I tried previously was all military, but this sim just gets me to enjoy just flying. I have a feeling I am going to spend a lot of time in this sim, and are surely going to recommend it. I hope it does not get cancelled, which leads me to the last section.

The open-source project


Great support, I have posted some questions, remarks on the forums, and gotten good response. And if you have an issue and your a programmer or 3D artist, well try fixing it yourself.

Number of users

No way to tell really, but the forums does not have a lot of activity recently, lot of time I am the only person logged in, that could be a bad sign (update: I just found out that the forum shows who is online in a specific subforum, not all online in all subforums, lots more people is online, sorry about that). You can say if the developers enjoy making the sim and do not make money depending on the number of users, why should it matter? Well, the more users, the more programmers and plane makers will stumble upon this great sim and help make it, add-ons and aircrafts. So it does matter.

Reporting bugs

Not only does Flightgear has a system to report bugs, it has a public bug-tracker. This sounds like a tedious thing to mention, but this is an incredible powerful feature. Firstly it enable the users direct contact to the developers, in a structured way. You log in using your Goggle credentials, use some minutes to report a bug or feature, and then you can track the bug, see the comments and status changes the developers make to it, and make further comments if you like. You can also view all other feature requests and bug reports by the rest of the community.

Under the hood

As I understood it the sim is programmed in C++. The graphics engine is done in OpenSceneGraph, which is a pretty good graphics system, similar to a system I have used myself, that one was not in C++ though. Some functions are made in Nasal, it sounds good on paper, but its web-page seems to not have been updated for many years, and made by a single person. Seems a bit risky, but I might be wrong. Aircraft makers can also tap into Nasal to make functions in the aircraft. It seems to be limited multi-threaded, but slowly moving towards being more. They consider using HLA, which is a military protocol, made for simulators to work together. I have programmed in that, and am not a fan, well at least not of the RTIs I have used. Flightgear supports Windows, Mac OS X, Linux, Unix.

How active is the development

The core sim seems to be developed by 18 people. That sounds like alot, but remember that this is all volunteers, and probably do not do this full-time. In fact, maybe I should give them a hand, I do have sim programming experience. But first, I am going to learn to fly, so maybe in some months I will consider doing that.

Sorry for the lack of screen-shots and videos, if you need them I suggest you try out Flightgear yourself and make some. This was my first review of anything ever, hope you enjoyed it, if not, feel free to flame me in the comments. I am off to fly F-16 in the Himalayas, bye. :)