Expert: Jeff Davis - 10/30/2005

Question
I was wondering if a maneuver I do with a F-18 computer simulator is an actual real fighter pilot technique. Normally when you turn a a plane you bank and make the turn with the ailerons.  With a simulated F-18 I find I have the power to put the fighter in a severe almost 90 degree bank and then make the turn with the plane's elevator, sort of like making a climb while the plane is flying sideways. Is this a real fighter technique? A real plane looses too much altitude in a high bank but a fighter has the power to not lose too much altitude, plus this seems to be a good way to turn quickly. The g forces are horrendous.

Answer
Thanks for the question, Paul.  I suspect that you don't have flight training but your observations from the simulator are very astute.  The short answer is yes, turning with the elevator is a real fighter technique.  The solution involves understanding what makes an airplane turn in a normal turn.  When the airplane is in level flight, all of the wings' lift is vertical, that is, the direction of lift is perpendicular to the ground, or straight up.  When you bank the plane, the direction of lift is no longer straight up; you can think of it as having both a vertical component and a horizontal component.  As you increase the bank, the horizontal component increases while the vertical component decreases.  If you don't compensate for the decrease in vertical lift, the airplane will lose altitude, therefore you apply some back pressure on the stick ("up" elevator) to create the additional lift needed to maintain altitude.  The greater the bank, the more up elevator you need; with steeper banks you will also need to add power (remember, when you're pulling on the stick to increase lift, you're also increasing drag).  Now let's crank our plane all the way over to a 90 degree bank.  At this point there's zero vertical lift; all of the lift produced by the wings is horizontal.  You increase lift by applying up elevator, and since ALL of the lift is horizontal, the airplane turns very quickly.  Theoretically you have no vertical lift, but in reality you get a small amount of lift generated by the side of the fuselage.  It's not nearly as efficient at producing lift as a wing is, but, depending on the shape of the fuselage, it provides some help in enabling the airplane to maintain altitude.  With the lift created by the fuselage combined with the airplane's momentum and available power, you can maintain a 90 degree bank for a certain amount of time.  Your observation is correct about the g-forces.  In level flight, of course, you're subjected to one positive g.  In coordinated flight, as the bank increases, the g-forces increase, to two g's at a 60 degree bank.  Theoritically, at 90 degrees, it takes an infinite amount of horizontal lift to overcome gravity and keep the airplane at altitude, therefore the g-forces are also infinite.  The real world g's are moderated somewhat by the factors mentioned above.  Rather than try to build enough momentum to ride out a 90 degree banked turn, real pilots stop short of 90 degrees, as you also observed, and we also raise the nose a little bit before entering the turn.  Next time your dogfighting opponent is on your tail, bank left 90 degrees, then push the stick hard for a sharp, negative g turn to the right.  Talk about horrendous!  Let me know if you have other questions, I enjoyed answering this one.  When flying outside the parameters that we think of as "normal," sometimes you have to think unconventionally to make the controls produce the movement you want, but it's all perfectly logical when you think it through.