[NSRCA-discussion] BS about snaps!

Fri Oct 16 09:09:23 AKDT 2009

One aileron would be the spoiler and one would be the flap--one decreases lift(instant 'stall') and the other would increase it on that panel.  SOMETHING has to affect the airplane to effect the "autoratation"; an imbalance of some kind--we just push it along with rudder, elevator and aileron--depending which way we want it to "auto-rotate"--and the entire sequence can and does happen in a blink depending on your style.

RS

> Date: Fri, 16 Oct 2009 09:52:01 -0700
> From: seefo at san.rr.com
> To: nsrca-discussion at lists.nsrca.org
> Subject: Re: [NSRCA-discussion] BS about snaps!
> 
> 
> There is a BIG difference between a basic stall (such as on landing) and 
> an accelerated stall (snap roll). I agree that people are getting too 
> wrapped up in the wording though.
> 
> One thing I disagree with is your assertion that the ailerons are only 
> functioning as spoilers once the stall happens. In full-scale aerobatics 
> that's true, but with F3A airplane wing loadings being what they are, 
> I'm betting that most simply can't 'snap' without ailerons. If that's 
> true, then the snap SHOULD be possible with elevator and rudder only. 
> 
> -Doug
> 
> 
> 
> 
> shinden1 at cox.net wrote:
> > Matt 
> > perfect explanation. common Sense prevails! 
> > its SET UP SET UP SET UP!!
> > We have tried to over complicate fundamentals of Model snaps for years
> > I know every one has stalled an airplane on landing before ..did you see a pitch break? No, the first thing you "saw" was one wing drop and the rest occurred immediately after. If you have the room, flying speed is the only thing that helps recover it.
> > Anything else you add speeds it up and worsens it.,,,,,Oh!!! 
> > I have just described a perfect spin entry too!
> > A snap is no different from a spin it`s a stalled "condition" the speed and inputs are the only difference in mantaining or stopping both maneuvers. it`s why you cant do a pos spin with a neg spin input.
> > Im Sorry Guys, but trying to legislate the perfect wording to judge poor snaps only worsens the problem, the description in place is all we need. 
> > the more we try to describe it ,the higher the scores will be for the guys performing it already. 
> > a perfectly performed FAI snap looks like A perfectly performed AMA snap.
> >
> > The bottom line is, it initially only takes one wing halve to stall before the chain reaction of events occur. the ailerons act as Spoilers after each wing half looses lift as it rotates pos and neg. the rest is predicated on CG position, the actual amount of throw in the remainder { including throttle ,,or Speed} of the surfaces that will mantain , over do, or perfect the rotational yaw,pitch , entry, and fuse angle at exit of the maneuver. 
> > Now,figuring out what causes each effect and how to adjust it is the teachable moment.
> > I submit the Guys who can Snap consistatly have the best trimmed airplane.
> >
> > The reason it`s the highest k-factor is, it`s the hardest to learn do correctly
> > the reason it`s not in the lower classes is because each class should teach the pilot how to advance in his airplane set up and trimming skills 
> > You just can`t pic up a airplane giver it the control inputs and expect good results If you put effort in the perfecting of all Snaps ,it can teach you more about set up and trimming of your model than any other thing we do with our airplanes. The Snaps Define wether your model is set up correctly Period.
> >
> > The good designers hang their collective hats on this maneuver when finalizing a design ,,Because this maneuvers will perfect the design or break it. When you get the snaps Perfect Every thing else in the flight demands improve ,when its not perfect you will have a few Maneuvers that suffer from the incompletion of the setup.
> > The demands of each class schedual should teach whats required ,,,if you are willing to take the time to experiment and learn.
> > There have been non engineers performing this maneuver correctly for decades 
> > Although the Explanation of the terms is help full ,,the proper execution of the snap is a better school master.
> > I submit the guys having to do the most selling on their snaps .( leading with up ,down,Elevator) are the ones trying to continually redefine it.
> > They just dont think it`s possible to perform the maneuver with no displacement ,,Hog Wash 
> >
> > Next year in the F11 pattern we have 2 versions of a 1.5 snap one from inverted and one from up rite . I promise you if we perform this maneuver to show a pitch leading break like some of what I saw judging the Nats this year the airplane will rise 2-5 meters before the rotation happens ,,, 
> > this is not a snap it`s a sell job. and the same guys doing that version on a 45 down line will severly downgrade ours.
> > there is no supper raidio super human input trickery to do a proper snap ,just a perfect setup.
> > FAI has to perform up line, downline and level snaps the same set up rules apply to all these if the airplane is set up right ! there will be the same input to do them all save if you have brakes on for the Elec guys LOL.
> >
> > So the guys that figure out how to do it with no departure will earn the Best scores Why ,because it`s precision in the setup delivers the best and the most consistent execution.
> > Fake stalls in the spins(switching from High to low rate trick) always produce a poor non predictable spin as well because you cant tell the "airplane" that it`s not stalled .sure you can get By ,But 
> > there will always be the Guy who can do it better with a better set up.
> > Try two spins in opposite directions with a fake entry Or for that Matter ,,two snaps opposite with a poorly set up airplane ,,,( Ask Beniot or Seba about this)Very poor results. when the airplane is completely set up it will have NO weak Maneuvers. You cant tell me Seba don`t know how to throw two stick in the corner for an inverted Snap LOL,,, no ,,,,He just cant Lead the Fake as well inverted. A Keen observer picked two snaps reversed from inverted at the Worlds because he could see the Forgery in the pos snap previos ,Seba fooled the Judges But not the Pilots .
> > The Judges applied the Rules ,,,the Pilots applied knowledge and common sense. saw the weakness in his set up and called him on it
> > I must tell you it made me happy to see it.
> >
> > So ,if you have consistent problems keeping a snap on line during the execution But see someone who can ,ask them about their setup.
> > but be prepared to change your "Whole" set up because like I said before 
> > Trim your airplane to fly all snaps and it will perfect the total setup demand and reduce the needs for rates, condition switches and the Like of the airplane ,Then force you to change your bad Habits in "every" Maneuver.
> > do you have the courage?
> >
> > Bryan
> >
> >
> > ---- rcmaster199 at aol.com wrote: 
> > 
> >> 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?
> >>
> >> _______________________________________________?
> >>
> >> NSRCA-discussion mailing list?
> >>
> >> NSRCA-discussion at lists.nsrca.org?
> >>
> >> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion?
> >>
> >> 
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