by: Miles Simmons

Split S Model performs one-half (1/2) roll in level flight then immediately executes one-half inside loop to level flight in opposite direction as entry. Downgrades:
  1. Half roll not 180 degrees.
  2. Half loop not started immediately after half roll.
  3. Half loop not constant radius.
  4. Changes in heading.
  5. One-half (1/2) roll not in level flight.
  6. Model heading does not finish exactly opposite the direction of entry.
Now for the Split S. This is basically an Immelmann Turn done backwards. Read the description above. Here's how you should perform this maneuver:
  1.  
  2. Enter from straight and level flight.
  3. Reduce the throttle to idle.
  4. Roll 180 degrees to level inverted flight.
  5. Allow the reduced throttle setting and gravity to start the loop for you. Resist the temptation to add elevator yet.
  6. Gently add up elevator during the first quarter loop. Maximum elevator deflection will be needed when the aircraft is pointing straight down.
  7. Gently reduce up elevator during the last quarter of the loop. If you maintain the elevator used on the first quarter loop, the loop will tighten (decrease in radius) on you and won't be round.
  8. Recover to straight and level flight and increase throttle.
Now let's check out the pitfalls.
  1.  
  2. Half roll not 180 degrees. Should be self-explanatory. Roll exactly 180 degrees to inverted flight!
  3. Half loop not started immediately after half roll. No straight flight is allowed before beginning the loop -- the loop must start immediately after the completion of the roll.
  4. Half loop not constant radius. Means just what is says -- make it round!
  5. Changes in heading. This can occur during the roll or during the loop. Use rudder as required to maintain heading.
  6. One-half (1/2) roll not in level flight. Roll must start exactly at the completion of the half loop -- not while climbing (over looping) or diving (under looping).
  7. Model does not finish in level flight. Straight and level flight one more time -- same song, 54th verse!
  8. Model heading does not finish exactly opposite the direction of entry. Heading on exit must be 180 degrees from heading on entry.
  9. Half loop not round. See #3 above.