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flying it     part of the aerobatic figure hammerhead
page created 30.06.2002 - 12:06, last modified 27.09.2002 - 12:15 by

   flying the hammerhead

The hammerhead is not a particularly difficult maneuver  to fly. Rather than demanding finesse it only requires the mechanical application of the appropriate control inputs at the appropriate moments to look right. Let's see how it is flown. In our example, the aircraft will pivot to the left at the top of the hammerhead.



The first order of business is to find a straightline ground reference, such as a road or power line. You will fly the hammerhead perpendicular to the road, so that you can look at it for reference on the way up, during the pivot, and the vertical down segment.



Establish hammerhead entry speed as you set up a flight path perpendicular to the road. At the entry speed establish momentary straight and level flight and neutralize the controls (the stick will have to remain forward of neutral because of the greater than trimmed for airspeed). Verify airspeed. Time the straight and level segment to take you directly over the ground reference line at the correct speed.



Aggressively pull up to establish the aircraft on the vertical upline flight path. You have to pull slightly more Gs than when flying a loop to achieve a crisp, solid transition to vertical flight.



As the horizon disappears under the nose, look at the left wingtip to monitor your position in the maneuver. When the wing chord line is perpendicular to the horizon, apply forward stick toward neutral to establish vertical straightline flight.



Your reference is the wingtip's position on the horizon, and your objective is to keep it stationary in its proper position relative to the horizon. Two controls are used to maintain position:


Rudder moves the wingtip up and down relative to the horizon (controlling yaw).


Aileron moves the wingtip backward and forward along the horizon (controlling roll).


As the aircraft slows on the way up and nears the top of the hammerhead, the slipstream tightens around the fuselage and might force the fuselage and tailplane right, requiring slight right rudder pressure to counter it. Your visual clue of this effect is a movement of the left wingtip downward relative to the horizon.



The wings produce less and less lift as the aircraft slows and at some point the torque force might exceed the effect of lift rotating the aircraft to the left along its longitudinal axis. Your visual clue of this effect is a movement of the left wingtip forward relative to its initial position on the horizon. Right aileron counters this effect and maintains the wingtip in its proper position.



Slipstream and torque effects are most noticeable in high-performance aircraft with small wings, such as Pitts. In training aircraft such as a Decathlon, the effect is too small to worry about during the initial stages of learning the maneuver.



The next phase of the hammerhead is the pivot. It requires the systematic sequential application of all three controls. As the aircraft almost comes to a standstill, the tightening slipstream mildly buffets the fuselage. The instant this happens, brisk full rudder must be applied in the desired direction of the pivot. This example pivots left; thus, you apply full left rudder.



As the aircraft pivots, the outside wing (in this example, the right wing) will travel faster than the inside (left) wing, generating more lift and rolling the aircraft left as it pivots. It is countered by full opposite (right) aileron.


In an aircraft with a propeller that rotates to the right, gyroscopic precession forces the nose of the aircraft toward the pilot during the pivot, tending to push the aircraft over on its back. It is countered with slight forward stick.


Thus the pivot requires three distinct sequential control inputs. It is imperative to perform them in sequence rather than simultaneously. You will find the procedure a mechanical exercise, requiring little finesse. To review, for a left pivot:


First, brisk full left rudder


Second, full right aileron


Third, slight foward stick



A note about "brisk rudder". It does not mean kicking the rudder. It is a swift, deliverate, but controlled push, rather than the lightning-flash fury of a kick. Very few things in life need to be kicked and an aircraft rudder is never one of them.



Now you look straight ahead and monitor the progress of the pivot. As the nose passes through the horizon, glance at the ground. The spot at which the wing (now vertical relative to the ground) points is the spot where the nose should point when it reaches the vertical downline.



As the nose reaches the point 45° short of the vertical downline, briskly apply full momentary opposite right rudder and simultaneously, in one continous process, neutralize all controls. When the controls are neutralized, the aircraft sould be on the vertical downline heading straight for the spot you saw along the wing when the nose passed through the horizon during the pivot.


Allow the aircraft to fly along the vertical downline to establish a recognizable straightline flight path along the vertical downline, and then pull out into a straight and level flight as you would from a loop. To achieve a crisp transition, pull about as many Gs as you did going into the hammerhead. When you exit the maneuver, you should be going 180° opposite to your entry heading.

last modified 27.09.2002 - 12:15 by ,
article created 30.06.2002 - 13:01

   hammerhead key list / video

For a short hammerhead key list navigate to the first hammerhead page. To see a hammerhead-movie navigate to the Bücker aerobatics-page.

last modified 27.09.2002 - 12:15 by ,
article created 30.06.2002 - 13:03

   about the hammerhead