[NSRCA-discussion] Suggested New Snap Roll (Brake Roll)Description

[John Pavlick]

Frank,
 In the Advanced Avalanche you don't have to push (negative snap) - you can pull if you prefer. 
 
John Pavlick

--- On Fri, 10/16/09, frank <frankjuliei at comcast.net> wrote:


From: frank <frankjuliei at comcast.net>
Subject: Re: [NSRCA-discussion] Suggested New Snap Roll (Brake Roll)Description
To: "'General pattern discussion'" <nsrca-discussion at lists.nsrca.org>
Date: Friday, October 16, 2009, 10:45 AM








 In the current Master’s sequence, the Avalanche with 1 ½  snap (from the bottom)-  The model is inverted and flies the first half of the outside loop.  The aircraft is  supposed to pitch up (pull) for the break, then perform the 1 ½  snap roll.  In the Advanced Sequence  Avalanche with a single  snap , the aircraft is  inverted at the top, but the pilot has to pitch (push)  before  the roll. In both situations, it seems likely  that  judges will have to look hard to see the break because of the altitude/location/climb of the model, no?.
 
 
 
Frank
 




From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of rcmaster199 at aol.com
Sent: Friday, October 16, 2009 9:43 AM
To: nsrca-discussion at lists.nsrca.org
Subject: Re: [NSRCA-discussion] Suggested New Snap Roll (Brake Roll)Description
 

Jerry Budd explained pretty well the fact that pattern planes are so lightly loaded that a large amount of force in pitch must exist to cause a stall. Stalls, accelerated and/or assymetric, I don't think are what happens in a pattern snap.

 

I believe an assymetry in lift does however. Think of the the wing as two halves (fancy that) where one sides lifts the equivalent of its whole area and the other side only a small percentage. Neither panel is stalled per se....one simply lifts less than the other. Yaw will induce the differential lift once the wing has been loaded in pitch. Assymetric lift will cause the wing to autorotate in roll axis.....we accelerate that autorotation with ailerons (duh!!). Some planes will snap with yaw command alone once pitch loading has happened. Most pattern planes will not because, as Jerry pointed out, it doesn't take a whole lot of lift to keep a pattern plane flying

 

My 2c

 

MattK

 

 

 

 
-----Original Message-----
From: Martin X. Moleski, SJ <moleski at canisius.edu>
To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
Sent: Fri, Oct 16, 2009 6:43 am
Subject: Re: [NSRCA-discussion] Suggested New Snap Roll (Brake Roll) Description

Keith Black wrote: 
> How about this definition: 
 
> At the start of a snap-roll, the fuselage attitude must show a 
> definite break and separation from the 
> flight path, before the rotation is started, since the model aircraft 
> is supposed to be in a stalled 
> condition throughout the maneuver ... 
 
That what Vicente (and others) are arguing is a bad 
definition for our purposes. 
 
I agree with those who want to remove all references to 
stalling from the definition of the maneuver. 
 
The model must depart (break away) from all three 
axes. Saying that the first departure must be separated 
from the other two does not make good sense to me. 
 
Demonstrating the kind of "stall" that leads to a 
spin entry is very different from the assymetric stall 
required for autorotation--at least in my own understanding 
of what accelerated stalls are like. 
 
  Marty 
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