How To Fly The X-31
By Erick Cantu
Introduction
The Rockwell International X-31 is, in my opinion, an easy and fun
plane to fly. But it has some erratic handling characteristics. In
this how to, we'll use Captain Slug's
X-31.
There are two versions of this aircraft, one for FS5 and one for FS98.
Since my flightsim is FSFW95, I use the FS5 aircraft. Use whichever you
like depending on your sim.The X-31 is an advanced technology demonstrator flown at NASA's Dryden Flight Research center at Edwards AFB in California. It incorporates a novel (though somewhat inferior to Lyulka's) TVC (thrust vector control) system employing 3 paddles (the Lyulka AL-37FU uses moving afterburner nozzles) mounted aft of the GE F404 Turbofan. The TVC system allows the plane to perform many maneuvers that most (and I said "most"...Flanker fans will agree) aircraft cannot, including the "mongoose" (which until now was known as the "cobra". (If you want to know what a cobra is, follow the URL: http://aeroweb.lucia.it/~agretch/RAFAQ/cobra.html). It has shown that it can fly at speeds lower than 50 kts (so can the Su-37MR). However, though the maneuvers are all old and were performed by non-TVC Flankers in the '80's, the X-31 is a nice plane and flies great.
X-31 (NASA)
X-31 Specifications
Length--43.33 feet
Span--28.83 feet
Max speed--Mach 1.28 @ 35000 feet
Power plant--1 GE F404-GE-400 Turbofan @ 16000 lbst
Max TO weight--16100 lbs
Service ceiling--40000 feet
Notes: served 524 flights in 52 months with a variety of operators. Pitted against current fighters in mock dogfights.
Flying The X-31
The X-31 only weighs about 16000 lbs and so has a thrust to weight ratio in the area of 1:1. It accelerates fast, takes off from Meigs with space to spare for a landing, and can turn on a dime. I flew it through downtown Chicago on dense scenery with dense air traffic, then landed at O'Hare. Of course, if this weren't a flightsim, I'd be in prison for a long time, with a heavy fine.
But the topic of this how to is flying the X-31 (and generally how to
perform special maneuvers), so I'll give a few pointers.
Never fly high Mach at low altitudes. This is true of most planes. Try it and you'll lose longitudinal stability. Perform a few kulbits (What's a "kulbit"? Follow URL: http://aeroweb.lucia.it/~agretch/Movies/su37.12.13.14.MPG) and crash. If you're starting to oscillate in pitch, deploy the airbrakes, press F1, and lower the gear.
If you stall, it doesn't mean that you're necessarily going to crash. Even if you lose control, recovery is easy within a few thousand feet. First hit F4, then F8, Then "G". Why do I say this? Well, when you have a departure in the -31, it's probably because you stalled the plane and kept the alpha at extremes for long periods of time. And now you're doing kulbits all over the place. Thrust recovers all that speed you lost. Flaps increase lift to help you recover faster. And gear down stabilizes the plane (ever see "Firefox"? I recommend you rent it if you've never seen it. Some of Clint Eastwood's best work.).
Takeoffs are very short, so if you want to fly under 200 kts, reduce throttle to 30% or you will find yourself accelerating way faster than you thought you were. Remember, this is not the 737-200A you usually fly (or at least the one I usually fly). That is partially why it's so fun to fly the X-31.
Auto Coordination Off! If auto coordination is on, you will stall and crash the second you start a high rate roll (true of all the planes). Why? I don't know (I am researching it, though).
Don't be afraid to go vertical after takeoff! The plane will stall, but usually recovers, and you will not lose control (usually). It has a great rate of climb.
Try the Bell (tailslide)! It's actually easy. I did it in the Learjet a long time ago. How do you do it? I'll tell you. First (smoke ON), at full throttle, go vertical, and hold 90 degrees, straight up. Then press F1, throttles to idle. Hold vertical, and you should stop and eventually start falling, still straight up. No stall. Drop the nose, throttle up, and press F6 once. Accelerate, then level off. This is possible in other planes too, such as the Learjet and Concorde. I recommend that beginners do this at around FL100 (Concorde even higher). Very similar to the hammerhead stalls performed in the Extra, but in a high performance fighter jet (hammerhead stalls are fun too)!
The "cobra" (dynamic deceleration) is one of the more challenging maneuvers. It requires practice. It also usually requires a Flanker, but is possible in the X-31. The first step is to decrease speed to around 280 kts, which is around the speed you would be traveling in a good dogfight. Next pull up sharply with flaps around 8 deg, until you are vertical (maybe beyond!). Speed will drop to maybe 120-130 kts almost instantly. When this happens, advance the throttle and drop the nose. Accelerate. The reason why I talk about being in a dogfight is that this maneuver is useful in those situations. Let's say you're in an Su-27 and your opponent is in an F-16C. You're both trading turns around 250 kts and he's behind you. Then you nail a cobra. Now you're traveling around 130 kts behind him. This gives you a chance to (depending on the situation) shoot a missile up his jetpipe or fire your cannon into his fuel tank. Don't expect to get it the first time. It takes practice.
Old maneuvers are suddenly different. Try the immelman, but pull up rapidly. You'll slide and find yourself flying in the opposite direction, but you didn't gain as much altitude. The split S is pretty much the same.
