Spinning Part 3, The Competition Spin

Adrian Willis
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In part 1 I introduced spins and explained the importance of learning to spin. In part 2 I explained the aerodynamics of the spin and the effects of various control inputs. In this blog I will describe the difference between a normal spin and the competition spin and then list the judging criteria. In my next blog (spinning part 4)  I will explain how to fly the competition spin and highlight some common mistakes.

A competition spin is a spin flown according to the judging criteria used in competitions. We will call everything else a normal spin.

If you make an error and end up inadvertently spinning, top of your priorities will be to recover and to do so without losing excessive height. Your immediate action should be to close the throttle and apply opposite rudder and relax back pressure followed by a little forward stick. In the “old days” we recommended that you should let go of the stick completely but some aircraft exhibit “Sticktion”, meaning the stick is sucked to out spin aileron and in these aircraft it is necessary to physically move the stick to the neutral position. The spin will stop almost immediately and as it stops you should neutralise rudder, apply power and ease out of the dive. Thats it, nothing more.  Every aerobatic aircraft must be capable of recovering from a spin provided the C of G is within limits. Rule number 1 is to not fly aerobatics without confirming the weight and balance is within limits. If recovery does not happen you have done something wrong. Check that the ailerons are neutral  and that you really have got full opposite rudder applied and the throttle really is closed.  If that is the case and there is no indication the spin is going to stop, you must have the wrong rudder applied, so change feet, then of course the aircraft must recover.

It is important to understand that you should train with a good instructor before attempting solo spinning, or getting into a situation that could lead to solo spinning.  I have seen many students in the heat of the moment make really basic errors that would have caused them embarrassment solo.  The old adage, “aerobatics has never killed anyone, but hitting the ground often does” is true. Always practice with enough height for things to go wrong and have sufficient height to recover before reaching your minimum height which in the early days should be at least 1,000 feet agl.

In aerobatic competitions we fly in front of a team of “expert” judges. Each judge marks each figure out of 10, deducting one point per 5 degrees of error, and then each score for each figure is multiplied by a k factor representing the difficulty of the figure. A one turn spin has a k factor of 15, so the maximum points that you can score is 150.

Judging rules have evolved to ensure the pilots performance is rated. Wind correction is therefore not required in figures where it would be impossible. So for example, the vertical down line in a competition spin is not wind compensated and therefore the judges are simply looking for the aircraft to be vertical, not its track. We use the Zero Lift Axis (ZLA)of the aircraft to establish this.

Competition Spin judging criteria:

  1. Approach on heading in level flight, no roll or yaw height gain or loss is wrong, lose 1 point per 5 degrees off heading
  2. A clearly visible stall, the nose should drop without the aircraft climbing.
  3. Roll and yaw should begin concurrently and lead immediately to the spin. If it flicks or is forced then a PZ (perception zero) is awarded.
  4. The rotation should stop and the nose should drop to vertical ZLA (Zero Lift Axis) with aircraft on correct heading. Any aileron assistance will cause loss of points 1 point per 5 degrees off heading or off vertical. There must be no perceptible aileron roll to establish the correct final down-line axis.
  5. Rolls on the downline must follow the spin after a short pause they are not centred
  6. Execute a constant radius pull or push to horizontal flight on the correct heading

 

If you want to learn how to spin properly and safely why not book an aerobatic lesson or a spinning and upset recovery course? For more details, email Adrian.Willis@BritishAerobaticAcademy.com or sms/telephone 07712864413.

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