[NSRCA-discussion] BS about snaps!

Fri Oct 16 10:03:46 AKDT 2009

Doug:
It IS possible--that's all we used to have, even with multi-channel reeds. 
Input full elevator, and rudder simultaneously.  Snaps looked just fine, as 
well as spins, with no aileron input; (You couldn't get but 2 channels at 
the same time).  It was, however, more difficult to control the exit point.
Bill Glaze
----- Original Message ----- 
From: "Doug Cronkhite" <seefo at san.rr.com>
To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>
Sent: Friday, October 16, 2009 12:52 PM
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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