[SPAM] Re: Displacement during snap rolls (was Why is it so
quiet?)
DaveL322 at comcast.net
DaveL322 at comcast.net
Wed Dec 29 10:23:58 AKST 2004
Errors in track can occur in pitch, roll, and yaw. They are all subject to downgrades on the basis of 1 point per 15 degrees.
Whatever the appropriate downgrade is for "excessive" vertical displacement on a snap should be the same downgrade that is applied for "excessive" lateral displacement. Depending on the position of the snap (viewing angle), the vertical and and/or lateral displacement may be very hard to see.
Snaps occur from a stalled condition - achieved by the "break" which must be visible. No break, score is zero. While there is not a specific downgrade for displacement (vertically or laterally), I believe the 1 point per 15 degree rule can be applied. If the overall geometry of a manuever is adversely effected by the displacement of the snap, the downgrade should be 1 point per 15 degrees of geometric error in the maneuver. For instance -
- 45 downline with 1 positive snap in calm air.
- Assume no other defects excepting displacement in pitch during the break.
- As measured between the finish of the entry radius and the start of the exit radius, the track of the plane is a 30 degree angle.
- The track of the plane is incorrect by 15 degrees. Using 1 point per 15 degrees the manuever would score a 9.
Obviously enough, the amount of displacement would have to be huge to change the overall line by 15 degrees - so in practice, the deduction would be much smaller than one point (if any).
Perhaps some relation to stall turns is possible -
- Stall turns can be downgraded for the upline and downline track not being parallel.
- Stall turns can be additionally downgraded for the pivot radius being too large (even when the upline and downline are parallel, but not superimposed).
Displacement in a snap is kind of like displacement in yaw at the top of a stall turn. Ideally, an airplane yaws about the CG in a stall turn - but this rarely happens in practice - so the rules allow for a nominal pivot radius (displacement) without downgrade. I think this same idea could be applied to displacement (vertical and lateral) of snaps - but it would have to be in the rulebook.
Thoughts? (as if this string won't run on and on for the next few days, <G>).
Regards,
Dave
-------------- Original message --------------
> This is another example of the intent of a thread wandering far afoot....as the
> original questioner, I'd like to refocus my point.
> Simply put - according to our CURRENT rules, there is NOT a downgrade criterion
> for offsetting of the track during a snap maneuver.
> I understand the "more skillful" guy should get a point reward (by not getting
> a downgrade that others may receive), but my point is ----
> What is the rule basis for the downgrade?
> And since I'm specifically talking about LATERAL track offsets, not vertical
> or angular, there aren't "general" guidelines to handle this.
> My point being that there SHOULD NOT be a scored difference between the line
> that shifts and the line that doesn't, all other factors being identical between
> the quality of the two snaps.....simply because we don't have the criteria
> identified.
>
> Or am I just being logical again?
> >
> > From: Bill Glaze
> > Date: 2004/12/29 Wed PM 01:39:00 EST
> > To: discussion at nsrca.org
> > Subject: Re: [SPAM] Re: Displacement during snap rolls (was Why is it so
> quiet?)
> >
> > Ed:
> > If a new track is acceptable, then, that is a de facto downgrading (by
> > not allowing for extra skill) that is being applied to the pilot who
> > can, and does, perform a real snap, as opposed to a "fake" snap, and
> > keep it on the same line. By not downgrading the pilot who shows a
> > different track even though it is parallel, you are not giving a premium
> > to the pilot who can perform the difficult task of keeping the snap on
> > the same line of the maneuver. It can be done; first time I ever saw it
> > was at the TOC on a vertical snap where all the competitors save for one
> > person, were offsetting their vertical snaps 2 wingspans to the right,
> > (double snap rolls, to the right) This individual was able to keep his
> > snap rolls exactly in line. They looked much better. Was he rewarded?
> > In a way, I guess. That year he won the TOC, but not, of course, for
> > snap rolls alone! BTW: I believe you were there that year, Ed.
> > Again: Sorry to be so prolux!
> >
> > Bill Glaze
> >
> > Ed Alt wrote:
> >
> > > Hi Dave:
> > > Track & heading are different things, so I'm referring to a new track,
> > > exactly parallel to the original one, being 100% acceptable. A new
> > > heading however, ought to be subject to the point per 15 degrees criteria.
> > >
> > > Ed
> > >
> > > ----- Original Message -----
> > > From: David Lockhart
> > > To: discussion at nsrca.org
> > > Sent: Tuesday, December 28, 2004 11:40 PM
> > > Subject: Re: Displacement during snap rolls (was Why is it so quiet?)
> > >
> > > More than 1 pilot was awarded 1 or more zeros in the 2004 US NATs
> > > F3A final on snap maneuvers. The "average" snap in subsequent
> > > flights in the finals showed more break / displacement (of course,
> > > any break / displacement is infinitely more compared to none,
> > > ahem.....).
> > >
> > > A stalled entry is a required element of spins - no stalled
> > > entry, score equals zero. No different for snaps. Judges are
> > > required to judge what they actually see (not what they think
> > > may have happened), and pilots are required to show / demonstrate
> > > / complete all required elements to avoid downgrades (which may be
> > > a downgrade to zero).
> > >
> > > To specifically answer Bob's question - my opinion - if the
> > > geometry of the manuever is not compromised, then no downgrade.
> > >
> > > Another question(s) - In a given maneuver involving a snap, the
> > > exit track of the plane is 15 degrees different than the track
> > > prior to the snap. What is the downgrade if the change in track
> > > is abrupt? What is the downgrade if the change in track is smooth?
> > >
> > > Regards and Happy Holidays,
> > >
> > > Dave Lockhart
> > > DaveL322 at comcast.net
> > >
> > >
> > >
> > > ----- Original Message -----
> > >
> > > From: Ed Alt
> > > To: discussion at nsrca.org
> > > Sent: Tuesday, December 28, 2004 11:04 PM
> > > Subject: Re: Displacement during snap rolls (was Why is it so
> > > quiet?)
> > >
> > > Good topic Bob. If the model really did a snap roll, it had
> > > to displace somewhat. If not, and if you could actually tell
> > > that it did not, that could be an indicator that a snap roll
> > > did not actually happen. Generally, the model has to displace
> > > to a new track, however slight, from the yawing and pitching
> > > moments introduced. The criteria should perhaps be that you
> > > are able to able to maintain the new track exactly in parallel
> > > to the pre-snap track. How much offset is OK is hard to say,
> > > but things generally start looking suspicious whan it's much
> > > more than a couple of wingspans. You would generally start to
> > > see other obvious problems, such as barrel rolling, if the
> > > displacement were really large. For another perspective, I
> > > think the Scale Aerobatics Flying and Judging Guide does
> > > a decent job of describing how to grade a snap.
> > >
> > > Ed
> > >
> > > ----- Original Message -----
> > > From: Bob Pastorello
> > > To: discussion at nsrca.org
> > > Sent: Tuesday, December 28, 2004 10:31 PM
> > > Subject: Re: Why is it so quiet?
> > >
> > > It can be very, very bad.
> > > Or not.
> > >
> > > Let's talk about displacement of the flight track during
> > > snap rolls. Whatcha y'all think? Is it downgradeable,
> > > and if so how much, and what is the criteria?
> > >
> > > Bob Pastorello
> > > NSRCA 199 AMA 46373
> > > rcaerobob at cox.net
> > > www.rcaerobats.net
> > >
> > >
> > >
> > > ----- Original Message -----
> > > From: Mike Hester
> > > To: discussion at nsrca.org
> > > Sent: Tuesday, December 28, 2004 9:21 PM
> > > Subject: Re: Why is it so quiet?
> > >
> > > Ya well, it's definitely not going on the primary
> > > bird. For that I have a trusty OS 160FX with vp30
> > > pump. I know it will run when I want it to run.
> > >
> > > Just like me "testing" a new design, testing my
> > > feather cut, testing my composite skillz (or lack of),
> > > so far so good. Of course I didn't make the YS, so
> > > that one is more of a massochistic tendancy methinks.
> > > I'm not skeert to spend a buck. Plus it wouldn't take
> > > too much to drop in an OS if it comes to it. I've
> > > gotta see for myself if the fire is as hot as it
> > > looks. I usually suffer 3rd degree burns right after
> > > one of these moments.
> > >
> > > Classic last words: "How bad could it be?" =)
> > >
> > > -Mike
> > >
> > > PS Ok ok NEXT year.
> > >
> > > ----- Original Message -----
> > > From: Bob Pastorello
> > > To: discussion at nsrca.org
> > >
> > > Sent: Tuesday, December 28, 2004 9:47 PM
> > > Subject: Re: Why is it so quiet?
> > >
> > > You have less than 3 days, then. Could be tricky
> > > for you.
> > > Besides, how does one "try" something that costs
> > > $700+ ? Sounds a bit like "testing" the $3500
> > > plasma tv.....
> > >
> > > Bob Pastorello
> > > NSRCA 199 AMA 46373
> > > rcaerobob at cox.net
> > > www.rcaerobats.net
> > >
> > >
> > >
> > > ----- Original Message -----
> > > From: Mike Hester
> > > To: discussion at nsrca.org
> > >
> > > Sent: Tuesday, December 28, 2004 8:38 PM
> > > Subject: Re: Why is it so quiet?
> > >
> > > YS SUCKS!!!!!!!!!!
> > >
> > > Better?
> > >
> > > =)
> > >
> > > -Mike
> > >
> > > P.S. I am actually going to try a DZ 160 some
> > > time this year. This could mean the apocalypse
> > > is near.
> > >
> > > ----- Original Message -----
> > > From: William C. Harden
> > >
> > > To: discussion at nsrca.org
> > >
> > > Sent: Tuesday, December 28, 2004 9:33 PM
> > > Subject: Why is it so quiet?
> > >
> > > I know someone out there has something
> > > interesting to say. So stir something up!
> > >
> > >
> > >
> > > Bill
> > >
> >
> >
>
> Bob Pastorello, El Reno, OK, USA
> rcaerobob at cox.net
> www.rcaerobats.net
>
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