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The Martin X-24A

From Astronautix.com

      The X-24A was the Martin Corporation's subsonic test version of the US Air Force's preferred manned lifting body configuration. This was flat-bellied with canted vertical stabilizers at the end of the rounded upper body. It was of the same configuration as the subscale X-23 Prime vehicle tested on suborbital flights in 1966 - 1967. Martin and the USAF hoped it would lead to a larger Titan III-launched manned orbital ferry vehicle (cinematically embodies in the 'XRV' spacecraft in the 1969 film version of Martin Caidin's novel 'Marooned'). The X-24A was air-launched from an NB-52 carrier aircraft and reached a maximum speed of Mach 1.6 and a maximum altitude of 21,800 m during its flight test. The X-24A handled well as a glider, but in powered flight it exhibited a nose-up trim change that prevented it from flying at low angles of attack. Air Force interest then focused on 'high fineness lifting body' configurations and the X-24A airframe was converted to the X-24B configuration.

The Temple Air X-24A

The X-24A in X-Plane takes advantage of the special controls setting for moving the ailerons in conjunction with the elevators. If you watch the aircraft from behind while flying, you can watch the coordination between those controls, the elevators being the upper set of horizontal control surfaces and the ailerons being the lower. The rear end of the X-24A is not modeled exactly like the real plane due to limitations of the X-Plane rudders, the original having two rudders on each fin while the X-Plane version is restricted to one. Also the rudder travel is rather restricted, since providing a larger travel will result in a wildly rolling flight! It also uses artificial stability for roll control. Feel free to change this in Plane-Maker and do some experimentation.

Power for the real X-24A came from an 8,000 pound thrust rocket motor, and this is modeled in the X-Plane version. For landing assistance the original also was equipped with two 500 pound thrust motors. To simulate this you can add throttle while landing up to about a value of "15" on the fuel flow meter. You may find this handy since the X-Plane X-24A tends to drop very fast while unpowered. If you are very, very good you can try a glider landing; just carry lots of speed and flare at the last moment. You can start your X-24A flight from a B-52 drop which is authentic, but it also can take off from a runway. Handling is pretty good but the sink rate builds alarmingly fast if unchecked.

I am making this early version available to the X-Plane community for three reasons. One is that the lifting body design has not been explored very much in X-Plane so I thought is would be a good "trial horse" for people to tinker with and make changes. Second is that I have tried with Paint Shop Pro to make a reasonable looking shiny aluminum finish and failed miserably, but perhaps someone else knows the secret and can do a decent exterior paint job. And finally I have crashed this baby so many times while it was in development that I feel I should share the misery with others!

The Martin X-24A is currently at version 0.8 and is flyable. The glider physics model is complete but the paint job is minimal. I haven't done a lot of testing with the rocket motor from a B-52 drop but it "feels" right.

Download the Martin X-24A version 0.8 (X-Plane version 5.62)

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