This is a question that has been asked a lot. By which I mean
a lot.
It is a complicated question. It all depends on how much money you have, which is the main thing. There's also a choice between different setups. Unfortunately, the joystick market is not exactly oversaturated, so sticks and such are going to be a little more expensive then you may expect.
Since this guide assumes that you want to play FS2_Open, which currently only supports one (1) Directinput controller at the same time, setups which don't allow for this (Such as the Warthog) will not be listed.
Keyboard and Mouse:Obviously the cheapest way, as you most likely already have both. There's quite some people around here that use the Keyboard for rough manouvres and the mouse for precision aiming. Some prefer it over joysticks.
Alternatively, you can use a script like this, which changes the mouse controls to a more freelancer style of doing things rather then the default "FPS style" of doing things.
Keyboard and Joystick:For a long time, this was my option. I often used cheap, second hand gameport joysticks in one hand and had my hand flying over various keyboard controls with the other. Luckily, you don't have to use cheap second hand gameport joysticks. There's quite a few options on the market, but there's only a few ones I can recommend.
Thrustmaster T. Flightstick X Joystick (30 dollars):
This is a beauty for the price. Although it has
potentiometers ("pots"), which are not as reliable as the magnetic sensors all the other joysticks on this list use, it has all the functions you ever need for any flightsim game. Rudder, Throttle, POV hat, and even adjustable friction . If you never used a joystick before and are hesitant to spend money, I highly recommend you get this one. Unless you are left handed.
EDIT: It has been reported this joystick has some deadzone issues. I personally think they are quite alright, but there you go. If you are worried about this being an issue, just look below.
Thrustmaster T-16000M Flight Stick (50 dollars):
In case you are left handed, or want to spend a little bit of extra money, this is a highly recommended stick. The first and most important bonus is that it can be disasambled and re assambled to fit the left handed. This alone makes it worthy of recommendation: No new other stick of this quality (or beyond this quality) can do that.
Another bonus is that it uses "Hall Effect" sensors for it's X and Y technology. In short, it uses magnets for it's stick movements, which is the same technology the ultra high-end thrustmaster Warthog uses. As a result, the stick itself is a lot more reliable, although the throttle and rudder twist still use pots.
It can also be programmed with Thrustmaster's high quality programming software, and can be used alongside their more high end products just fine.
Microsoft's Sidewinder Joystick (Second hand):
The time that Microsoft made PC gaming peripherals is long gone, and the Sidewinder has since been retired. However, if you can snuggle this legend up a flea market or whatever, you do get the best Force Feedback joystick ever made (According to various flight sim enthusiasts). A pity it has been cancelled. It originally sold for 100 dollars - now the prices on it are much higher.
CH Products Fighterstick (100 dollars):
In case you don't have a lot of money now but will have later on, just buying this part of the legendary CH products HOTAS system (further explained below) can be a smart choice. Read on below on why this is.
HOTAS systems:
Hot ass? No, these systems don't have that (Although they will attr... nvm). HOTAS stands for "Hands-on-Throttle-and-Stick", which means that, just like in modern fighter aircraft, you don't have to remove your hands from the throttle and the stick to acces all of the sticks functions. As a result, these sticks are highly programmable. The Saitek X52, for example, has 30 buttons and several POV hats. It also has a "pinkie switch", which functions similar to a shift or ctrl button. It also has three different modes. As a result, you'll never want for buttons for any of these sticks. You can setup different modes for different uses: Dogfighting, subsystem bombing, all that stuff. Don't worry: You won't have to. But once you get used to it, you can't live without it.
These systems do take a lot of time to setup though. To get full functionality, you have to "program" them. It's not as hard as it sounds, but it does take a while.
These joysticks are rather expensive, but do use full magnetic sensors for all their control axes, making them more reliable.
Saitek X-52 (110 dollars):
If you want to try an HOTAS, try this one. It's the cheapest HOTAS system available, it has a ton of programmable buttons and it looks cool. I have one. I love it. It also has a nice HUD which tells you the name of the function you assigned to a button (if you used the profiler that is). I had some problems with the drivers, but support has been nice and the issues have now been resolved trough updates. Which is very neat.
Although I neglected to mention this: The two parts of the joystick (throttle and joystick) are connected using a PS/2 cable. This cable can ocasionally knock loose for a split second, which throws the calibration off. This happens to me that I don't care much for it, but the fix is simple: Pause the game, pull out the cable entirely and pull it back in again, nad you have got yourself a fully calibrated joystick again.
Saitek X-52 Pro (140 dollars):
If you have a little bit of extra money, try this one instead. The X-52 pro has a few extra features, which you don't need. It does, however, have a significantly higher build quality.
CH Products Fighterstick - CH products Throttle - CH products Rudder (over 300 dollars):
When you hear about "CH products", two things come to mind, depending on your line of work. It's either "Who are they?" or "They make entertainment products?". That is because CH products is not a gaming company. It is a company which produces controllers for industrial applications, who happen to have a side hobby which is producing flight sim gear. As a result, their sticks are EXTREMELY reliable (after all, unreliability can be lethal in their line of work, or unfathomably expensive at best). And - CH even sells replacement parts! Their sticks don't look as flashy as other products (the only change to their line up in the last decades has been switching from gameports to USB), but they don't lack in functionality, nor do they lack in build quality (you will find the same plastic you find in Boeings). If you have the money, this is the "Buy this and you will never buy anything else ever again" option.
Their programming software is also of a very high standard (although I did not find the X52 software lacking in any way, apperently the CH products one has even more functions). Also, if you are daunted by the price, you can buy the components seperately.
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This guide is a bit of an WIP - suggestions and testimonials are highly welcome. I intend this to become a sticky.