[NSRCA-discussion] basic judging question

[Woodward, Jim (US SSA)]

Hi Bob,

It is long taught in precision aerobatics that the stall turns are supposed to be wind corrected, and this may result in a pivot of less than 180 degrees, and this is OK.  Vertical lines should be wind corrected (imagine flying a stall turn in the cross wind, or a head wind - all lines should be wind corrected best you can).

However, this dovetails into the recent IMAC & Pattern comparison threads.  In IMAC, the plane is supposed to be brought into the "vertical plane" prior to the stall-turn(pivot) taking place.  This is mostly evident if you are flying in a strong headwind where you are wind correcting the vertical line.  Just prior to the stall turn, the pilot hast to pitch the plane into the vertical plane, then yaw around the pivot, then return to the wind corrected down line.

Thanks,
Jim



From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Bob Richards
Sent: Tuesday, October 06, 2009 6:49 PM
To: NSRCA Mailing List
Subject: [NSRCA-discussion] basic judging question


Stall turns. I know the rules talk about the "track" of the model vs the heading (wind corrections). However, for stall turns, is the model supposed to be perfectly vertical at the moment the stall turn begins? Under the general stall turn description in the rules (page RCA-20), nothing is mentioned about heading, only "paths", so I would assume wind correction carries through the stall turn, such that if the plane is correcting for wind blowing from the left side of the plane, and the stall turn is performed to the left, then the heading change will be something less than 180 degrees.

However, trying to look in other places for more specifics, I find the Double Stall Turn w/ 3/4 rolls, and the Figure M (RCA-22).  In both, the downgrades list "Model not vertical at start and finish of rolls and stall turns". Hmmmm, "model" instead of  "path". Also, "stall Turns not exactly 180 degrees". Confusing, at least to me.

However, looking a little further at the "Stall Turn with/without rolls" description (RCA-29), it is specifically mentioned that downgrades include "Model track not vertical at start and finish of rolls and stall turn". I think the descriptions for these maneuvers need to be consistent. Which is correct? (I think the latter is the correct one). What is the consensus? Is it too late to enter a rules change proposal?

Bob R.



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