Acro Image

Aerobatics Server

ACRO E-mail Archive Thread: [IAC] Snap question

[International Aerobatic Club] [Communications] [Aerobatics Images]

Disclaimer: These aerobatics pages are developed by individual IAC members and do not represent official IAC policy or opinion.

[Usage Statistics]

ACRO E-mail Archive Thread: [IAC] Snap question


Thread: [IAC] Snap question

Message: [IAC] Snap question

Follow-Up To: ACRO Email list (for List Members only)

From: allan franko <allan.franko at>

Date: Thu, 15 Jul 1999 23:10:15 UTC


  There's an aspect of snapping my S-1S that has puzzled me 
for a many years.  Perhaps someone who understands the 
aerodynamics of snaps can take the time to explain it.

Crossover snaps (where the loading of the wings changes as 
the snap starts, such as an inside snap from inverted or 
and outside snap just after a pull to vertical) work only 
when I do everything wrong.  To end on heading I have to 
snap against the engine, creating an unnecessarily large 
displacement of the nose, and I have to keep the elevator 
at the stop throughout.  These snaps look buried because 
they really are buried, and they consume a lot of energy.  
Either unloading after the break or snapping with the 
engine causes me to end off axis in pitch and yaw, 
regardless of what I do to the other variables I can think 


Allan Franko
allan franko
allan.franko at


© Dr. Günther Eichhorn
Email Guenther Eichhorn