Displacement during snap rolls (was Why is it so quiet?)

[Archie Stafford]

Last year at the NATS the biggest thing they were looking for was the break.
You really had to show a VERY clean break.  The rule book doesn't specify
how much break, but it was obvious last year that you really had to show a
VERY clean break, even on the avalanches, which is very tough to do at the
top of a loop and give a good break, or in FAI the snap at the bottom of the
loop.  I talked to Andrew Jesky as well and he said the FAI judges were
being the same way, the you really had to show a very definite break.
 
I think the key to the displacement is how much rudder is in the snap.  From
my experience if you have too much rudder the plane will displace from one
side or the other.  You can take out some of the rudder and still have a
truly stalled maneuver.  You use the elevator to stall the aircraft.
 
I do have a question though.  How can an aircraft be "semi-stalled?"  Either
the aircraft is stalled or it isn't. 
 
  _____  

From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On
Behalf Of Randy
Sent: Wednesday, December 29, 2004 9:32 AM
To: discussion at nsrca.org
Subject: Re: Displacement during snap rolls (was Why is it so quiet?)
 
Man I would love to see a video of different snaps and the judges scores
from last years NATs.
Randy
----- Original Message ----- 
From: John <mailto:johnferrell at earthlink.net>  Ferrell 
To: discussion at nsrca.org 
Sent: Wednesday, December 29, 2004 9:19 AM
Subject: Re: Displacement during snap rolls (was Why is it so quiet?)
 
As near as I can tell Somenzini's secret is in the setup, not the snap
itself. 
The only place I see to downgrade for offset is in presentation.
 
I admit to being one of his fans.
 
I think the question is a very good one!
 
John Ferrell    
http://DixieNC.US
----- Original Message ----- 
From: Bob Pastorello <mailto:rcaerobob at cox.net>  
To: discussion at nsrca.org 
Sent: Wednesday, December 29, 2004 6:47 AM
Subject: Re: Displacement during snap rolls (was Why is it so quiet?)
 
Good points, David, but my question is based on a LATERAL, and "Parallel"
shift in the track.  Assume that I get 'lucky', and nail the line before the
snap, definitively BREAK during the snap, nail the exit on the original
heading/track, but shifted sideward maybe 3 feet.
    My experience is that a properly-executed snap manuever - anyplace -
MUST translate some forward momentum into angular sideward momentum, thus
shifting the track of the manuever.
    If this is a "downgrade", where is the criteria, how much are the
downgrades, and since we're not talking about an "angular" offset, the point
per 10 or 15 degree deviation rule doesn't seem to fit.
    In fact, I would argue (and I'm confident there are aerodynamicists out
here who could calculate and prove it so) that NO appropriately-executed
snap manuever CAN occur without offset of the original track.
 
    If someone does the imitation/fake "snap roll" ( the rapid, low-rudder,
high-aileron, semi-stall ROLL) there ISN'T an offset, usually.  At least in
the fake ones I judged LAST season.

Bob Pastorello
NSRCA 199  AMA 46373
rcaerobob at cox.net
www.rcaerobats.net
 
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