While my iPhone has always felt relatively fast, now I can say it really flies--and no, that's not due to the 2.1 software update, though that helped. Instead, my iPhone can now literally fly, thanks to Laminar Research's X-Plane for iPhone. This is the first flight simulator for the iPhone, and if nothing else, it's an amazing testament to the power of the iPhone's CPU and graphics capabilities. But I'm getting ahead of myself...
X-Plane for iPhone is based on X-Plane, which is the most advanced flight simulator available for the Mac. (We reviewed version 8.0 back in 2005; version 9 is now current.) It has an advanced flight model, realistic and dynamic weather, the ability to fly hundreds of planes, and a worldwide database of airports and navigation aids (such as VORs and NDBs). Each airplane has a fully functional panel, containing all the key instruments you'd find in the real version, and the mix of airplane types available is huge--everything from gliders up to a 747 jumbo jet. In short, X-Plane is the state of the art in flight simulation on the Mac.
The iPhone version of X-Plane is a slimmed-down version of the desktop product--X-Plane for the Mac requires something like 60GB of disk space for a full install, so that's not going to work well on an 8GB or 16GB iPhone. The iPhone install, on the other hand, weighs in at just 7MB. So what do you give up in the move to the iPhone? First of all, the world is much smaller--the entire planet is a roughly 1,600 square mile area around Innsbruck, Austria. Within the world, there's but one airport, and no cities. There are also fewer aircraft, a reduced-accuracy flight model, and no navigation aids.
While this all sounds quite limiting, it's implemented very well, and the end result is a very usable simulation/game. Flying in X-Plane is very intuitive--there are sliders on each side of the screen to control the throttle and flaps, two buttons in the center for gear and brakes, and a row of buttons across the top to control the view and set up the simulator. All of these interface elements are typically in a near-transparent state; when you touch the screen, though, they turn opaque, making them easy to use without being visually distracting.
So how do you actually fly X-Plane? Using the iPhone's built-in accelerometers, of course. To take off, move the throttle slider to the top of the screen, move the flaps slider down a notch if you wish, and then release the brakes. As the airplane accelerates, tip your iPhone towards you (X-Plane for iPhone runs only in landscape mode), and watch the nose come up. Once the aircraft is off the ground and climbing, raise the gear, zero the flaps, and then tip your iPhone left or right to initiate a turn. It's incredibly intuitive and very easy to master--the sensitivity of the interface is just about perfect. I have noticed that, occasionally, X-Plane seems to lose track of the iPhone's position, requiring me to tip the phone further and further just to keep the same nose angle. I can usually clear this just by turning left or right, then returning to level flight.
You can fly one of four aircraft (a Cessna 172, Columbia (now Cessna) 400, Cirrus Vision jet, and Piaggio Avanti), and all four share the same greatly-simplified instrument panel--it's not really a panel at all, but a heads-up display that's displayed on top of the moving scenery. On the heads-up display, you'll see everything you need to fly--airspeed and altitude indicators, an artificial horizon with flight path indicator, a compass (with a needle that points to the one airport), and throttle and flap position indicators.
X-Plane offers three external views in addition to the cockpit view. My favorite is the "chase" view (the second button from the left at the top of the screen). In this mode, you can move the virtual camera by dragging the screen, or zoom in and out with the pinch gesture. For real fun, choose an external view, set the camera so you can see the underside of the plane, then raise and lower the landing gear--the gear animates up and down in a smooth and realistic manner.
You can also choose between four different times of the day, and customize the winds, the cloud cover and weather, and the airplane's weight and balance. (You can set the base altitude for the clouds, but you can't control how thick the cloud deck is; that seems to vary based on the weather you've chosen.)
Most of the graphical goodness and flight model accuracy from the desktop version has made the move to the iPhone, so when you're flying, the views are pretty amazing, and the plane responds (mostly) realistically.
There are some concessions to lessen the load on the iPhone's CPU--you can, for instance, enter a 90-degree banked turn from a maximum-speed dive without any damage to your aircraft. Try that same trick in X-Plane for the Mac (or in a real plane!), and you'd basically fold your wings in half, ending your flight very quickly and painfully. These concessions pay off in usability, however--the game has a good frame rate, and I was able to play for over an hour straight with only a slight change in the battery indicator when I was done.
Real planes also have limits on the speed at which gear or flaps can be deployed; those limits are missing in X-Plane for the iPhone. But such details in X-Plane for the iPhone would take away from the sheer fun of using the game; the area around Innsbruck is quite mountainous, and it's quite fun to go fly the canyons in the Cirrus jet, for example--something you'd never try in a real aircraft.
Despite being based on version 9 of the desktop product, it's important to note that this is a version 1.0 release. As such, I ran into quite a few things that either didn't work quite right, or could be improved with a software update.
The most annoying bug is that you can't really sleep your iPhone when X-Plane is running--press the Sleep button while in X-Plane and the iPhone's screen goes black, but the game's audio will keep playing (though the game doesn't seem to react to the accelerometers). Left in this mode, the iPhone's battery will drain quite quickly, obviously. When I then "woke" the iPhone, I found the accelerometers in the game were messed up--the only fix for that was to quit and relaunch X-Plane. So if you're playing X-Plane, don't put your iPhone to sleep; quit the program first, then press the Sleep button.
The game also won't remember its state if you get a phone call while playing; when you hang up the phone, X-Plane will start again, but you'll be back on the runway. There's also no way to say "save my current position" if you want to stop using X-Plane for a bit and then resume where you left off. The propellers on the prop planes are animated in external views, but they turn so slowly that they wouldn't cool off my den on a hot day, much less help lift a multi-thousand-pound aircraft into the air.
X-Plane won't remember your settings for preferred aircraft, sky condition, or winds between launches--each time you start the game, these things reset to their default values. Finally, the program crashed a few times during my tests, usually when I moved the camera about in an external view. Given Laminar Research's record of frequent updates to the desktop version of X-Plane, I would expect that we'll see the same with the iPhone version--so these bugs and glitches should hopefully be fixed in a soon-to-be-released update.
Unlike X-Plane for the Mac, X-Plane for the iPhone isn't intended to be a pure flight simulator with incredible realism in all realms; it's main focus is on having fun while providing a somewhat realistic and visually interesting flying experience. By that definition, X-Plane for iPhone is a tremendous success. The 3-D graphics are incredible, flying with the accelerometers is intuitive, the interface doesn't get in the way of the visuals, and the variety of views, weather, and aircraft keeps things interesting and fun. If you have any interest in flying, X-Plane for the iPhone--despite the bugs in version 1.0--is a great way to get your flying fix while out and about.
X-Plane is compatible with any iPhone or iPod touch running the iPhone 2.x software update.]
[Senior editor Rob Griffiths has fooled around with a flight simulator or two during his time as a Mac user.]
This story, "X-Plane 9 for IPhone" was originally published by Macworld.