[NSRCA-discussion] How I became an expert Snap Judge (TIC)
Vicente "Vince" Bortone
vicenterc at comcast.net
Thu Oct 15 11:34:45 AKDT 2009
Jason,
Probably you need this one from Chris Moon. I need to follow his instructions and read it many times. I think there was another one but I can not find it:
> Ahhh .
> angle of attack is not the same as the aircraft
> attitude.Websters defines angle
> of attack as "the acute angle between the chord of an
> airfoil and the line
> of relative air flow". The relative wind flows
> parallel and opposite
> the direction of the wing's movement through the
> air.The wing's attitude as we
> see it from the ground is NOT the same as angle of attack.
> If you are in a
> vertical climb is the wing stalled? After all it is
> 90 degrees ATTUIUDE
> from your perspective on the ground, right? But the wing is
> not stalled because
> the relative wind is coming parallel and opposite the
> direction of flight. You
> can be in a nose low descent and stall a wing. Now
> take a straight and
> level pass and give it an instantaneous large amount of up
> elevator. What
> happens? First, the plane continues in the direction it was
> going (straight
> ahead) for a short time, but what is important is that the
> angle between the
> relative wind (straight ahead) and the wing which is now
> pivoting up increases
> until it reaches the critical angle of attack and it
> stalls. Without
> knowing the specifics of that wing design, we can't
> know when exactly this will
> occur, but it can be extremely fast and at a relatively low
> ATTITUDE in
> relation to the ground. Hence, you do not need a high
> nose ATTITUDE in
> order to have a high angle of attack. There are too many
> variables for one to
say that they need to see a nose high attitude in order to
> define a high angle
> of attack and thus a stall. Remember also, that
> different wings have a
> different critical angle of attack where a wing will
> stall. How does
> anyone know where that angle is without a wind tunnel and
> testing? and who am I
> to say it did not pitch up enough to stall therefore I
> giveth the pilot a 5 or
> zero even though I cannot possibly know the particulars of
> the wing that I am
> watching.
>
> My comment of the 1-2 degrees was to say that we do not
> know how closely any
> particular wing is flying from it's critical angle of
> attack. If it is in
> fact close, a change of only 1-2 degrees can cause a
> stall. We are trying
> to be aerodynamic engineers from the ground and deciding
> for ourselves what the
> angle "should" look like and downgrading
> accordingly. Now throw
> in the conceptual difference between angle of attack and
> aircraft attitude, and
> it is easy to come to the wrong conclusion about stall or
> no stall. Are we
> fling only 1-2 degrees from the critical angle most of the
> time, no but the
> point it that there is absolutely no aerodynamic
> requirement for a very nose
> high ATTITUDE to be a requirement in order to get a high
angle of attack on the
> wing.
>
>
>
> Chris
Vicente "Vince" Bortone
----- Original Message -----
From: "J Shu " < jshulman @ cfl . rr .com>
To: "General pattern discussion" < nsrca -discussion at lists. nsrca .org>
Sent: Thursday, October 15, 2009 1:46:52 PM GMT -06:00 US/Canada Central
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)
But they left NO doubt about pitch break... isn't that what everyone needs to see, or did I delete too many posts without reading them?
Regards,
Jason
www.shulmanaviation.com
www.composite-arf.com
----- Original Message -----
From: Vicente "Vince" Bortone
To: General pattern discussion
Sent: Thursday, October 15, 2009 2:42 PM
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)
and SEBANDREW SNAP for the not normal one.
Vicente "Vince" Bortone
----- Original Message -----
From: "Vicente \"Vince\" Bortone " < vicenterc at comcast.net >
To: "General pattern discussion" < nsrca -discussion at lists. nsrca .org >
Sent: Thursday, October 15, 2009 1:40:03 PM GMT -06:00 US/Canada Central
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)
Let's called NORMAL SNAP.
Vicente "Vince" Bortone
----- Original Message -----
From: "J Shu " < jshulman @ cfl . rr .com>
To: "General pattern discussion" < nsrca -discussion at lists. nsrca .org>
Sent: Thursday, October 15, 2009 11:45:13 AM GMT -06:00 US/Canada Central
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)
I don't remember anyone saying they received a 0 at the Worlds. Andrew and Seba had the 'IMAC' pitch break, most of the the rest of us had the 'normal' snap.
One thing I found funny was some of the other pilots that would 'show pitch break' would actually do mostly a roll afterwards. I guess if you 'show pitch break' the plane 'must be stalled' right...lol.
Regards,
Jason
www.shulmanaviation.com
www.composite-arf.com
----- Original Message -----
From: Vicente "Vince" Bortone
To: General pattern discussion
Sent: Thursday, October 15, 2009 12:35 PM
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)
Jason,
It will be interesting to know at the WC in Portugal. I never got one in local contests this year. I don't think at local contest we are zeroing even when there is not a clear snap. At the Nats I zeroed some years ago. I never got a complain. I have been downgrading 3 points for not presenting the break in pitch trying to use the current snap description.
Vicente "Vince" Bortone
----- Original Message -----
From: "J Shu " < jshulman @ cfl . rr .com>
To: "General pattern discussion" < nsrca -discussion at lists. nsrca .org>
Sent: Thursday, October 15, 2009 11:17:46 AM GMT -06:00 US/Canada Central
Subject: Re: [NSRCA-discussion] How I became an expert Snap Judge (TIC)
Just curious... how many are getting zero'd for doing snaps?
Regards,
Jason
www.shulmanaviation.com
www.composite-arf.com
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