With two pilots on staff, iLounge is probably as receptive to the idea of an iPhone flight simulator as anyone: unlike “flying games,” which offer shooting and high-speed excitement, proper flight simulators actually fit into a separate category of application, presenting intellectually challenging computer-generated versions of real-world flying scenarios. To game players, such simulations may seem relatively simple — or even boring — but creating a realistic flight model with believable instrumentation and environments requires significant computational power. As the first flight sim for the iPhone and iPod touch, Laminar Research’s X-Plane 9 ($10) is an outstanding demonstration of the power that the iPhone platform offers, bringing a computer-like flying experience to pocket devices. It is also setting new standards for the quality of post-release updates; though the company created the first iPhone version of the application in only two weeks, we opted to wait until the latest version, 9.03, was released in order to bring you a picture of what Laminar could accomplish with a more reasonable development window.
At a basic level, X-Plane functions by using your device’s accelerometer to simulate aircraft control movements; tilt the iPhone back to pull the stick back, tilt forward to push the stick forward, and tilt left and right to move the control stick in that direction. On the ground, left and right movements simulate nosewheel steering, while in the air they move the ailerons to roll the aircraft. Rudder controls are not presently available in the iPhone application.
An on-screen heads-up display is shown to provide instrument readouts for airspeed, altitude, heading and horizontal situation. Two buttons are provided at the bottom for wheel brakes and landing gear, if you’re flying an aircraft with retractable gear. Throttle and flaps are adjusted by sliders at the left and right sides of the screen that only appear when you’re touching or adjusting them.
Taking off is as simple as tapping to release the brakes, sliding the throttle up, and then tilting back your device once you reach rotation speed.
Once airborne, the iPhone accelerometer is used to maneuver the aircraft, with very realistic control sensitivity appropriate to the aircraft that you are piloting. You can select from four different aircraft: a Cessna 172, Cirrus Vision, Columbia 400 and Piaggio Avanti, with specific flight dynamics and features unique to each aircraft.
In addition to the standard first-person in-cockpit view, a number of external views can be accessed by tapping on the center of the screen to display menu buttons, and then selecting between the first four buttons. The first button is the standard cockpit view, and the second switches to an external view that you can pan and zoom using standard multi-touch controls. X-Plane’s remaining two views represent a stationary ground-based spot view and a linear-spot view that matches your speed and flight path. Zooming is also available in the spot and linear-spot views.
The button on the far-right of the menu bar will enable a graphic display of the actual forces acting on the aircraft for any of the external views, presenting a visual display of the flight model.
External views provide realistic representations of the selected aircraft, and even include displays of appropriate control surface movements: lower the flaps and you can see them lowering on the aircraft; tilt the iPhone from side-to-side and you can observe the aileron movements.
The application also includes stunning scenery, with mountains and lakes present, and although you are limited to a relatively small geographic location as compared to the desktop version, the area does include a reasonable variety of natural scenery, three airports that you can fly between and a single VOR navigation aid. A map view can be found in the app settings which shows you the general topography, airfields, navigation aids, and your current position. You can zoom and pan around the map view with normal multi-touch gestures, and even rotate the map with two fingers. Buttons at the left-side of the map view allow you to set your plane to different starting points, if you want to practice approaches, for example.
On the subject of navigation aids, the most recent version of X-Plane also includes an instrument panel view with a full set of standard instruments including airspeed, HSI, altimeter, turn and bank indicator, VOR and heading indicator, and VSI.
Scrolling down on the instrument view displays two navigation radios that can be used to set the VOR or ILS frequencies and switch between them. Tapping to the left or right of the instrument control knobs for the radios or VOR will adjust the instruments appropriately.
In instrument view, you can actually conduct full IFR (instrument) flights, and even shoot ILS approaches to two of the three airfields with full track and glideslope support. ILS outer/inner markers and ILS back course approaches are not present for the included airfields, but this is not unrealistic.
In addition to the map view, the settings screen allows for complete configuration of your flight experience, including time of day and sky conditions—including ceiling and visibility—wind speed, turbulence and direction, and even your aircraft’s weight and center of gravity, which will be reflected in the flight dynamics and performance of your aircraft.
The iPhone or iPod touch accelerometer can also be calibrated for both pitch and roll from within the settings, allowing for fine manual adjustments or a simple center-point calibration.
One important point about X-Plane is that many users, ourselves included, have had problems with the application not starting. However, this appears to be more an iPhone OS issue than a problem with the X-Plane application itself, particularly since we’ve seen the same behavior in even some moderately-demanding iPhone applications. A reset of the iPhone consistently solves this problem.
When you consider the sheer quantity of math and physics that go into a proper flight simulator, X-Plane 9 is quite possibly the most sophisticated iPhone application we’ve seen. The flight model it presents is extremely realistic, right down to the inclusion of details like real-world turning errors on the HUD’s magnetic compass and gyroscopic drift on the heading indicator, with enough realism for this to actually serve as a flight training aid, particularly for instrument training. In fact, the only real limitation on the flight model presently is the lack of direct rudder control, however, this really only affects the ability to perform more complicated aerobatic maneuvers; it is not a serious limitation for a normal flight experience, since turns are automatically co-ordinated when rolling.
It is also worth noting that the developer has thus far been very aggressive in the addition of new features to X-Plane with each 0.01 version actually being a much more major upgrade than you would expect—again, the instrument panel and ILS support were only added in 9.03.