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Old 11-18-2008, 10:15 AM
sukhoi26mx is offline
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Scott Stoops
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Re: The perfect Snap, El Snap perfecto??

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Originally Posted by JLeyland View Post
Precision full scale snaps require aileron.
Agreed. Although in a perfect world a snap roll would be a rudder/elevator maneuver, most competition airplanes require aileron to be predictable and precise. In my Sukhoi, I use full aileron in the direction of the snap and a lot of other tricks to make the snap appear deeper than it is (the stalled nature of the snap and observable stall is a huge player in scores in the full scale world.) I also unload the snap almost immediately after it releases with a dramatic down elevator input (for a positive snap) to accelerate the rotation and minimize energy loss. Is there a "right way"? I think there is a right way for each particular airplane. It's just a matter of finding the technique that consistently scores the best for your model.

Scott
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Old 11-18-2008, 11:34 AM
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Re: The perfect Snap, El Snap perfecto??

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........ I also unload the snap almost immediately after it releases with a dramatic down elevator input (for a positive snap) to accelerate the rotation and minimize energy loss. ...............
I used to try and tell people I did this to speed up a POSITIVE snap and they didn't believe me....

Often this can be observed in a spin... get a spin started, upright/positive and slowly transition to neutral and then to down elevator... the spin rate will increase... and yes it stays positive... (Unless you have 3D elevator deflections... then it may finally push over)
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Old 11-18-2008, 09:04 PM
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Re: The perfect Snap, El Snap perfecto??

Scott, Mith, John, Bruno and everyone else who is partaking in this thread.

I suppose my point is while full scales use aileron in a snap a technically perfect snap would be an elevator - rudder manoeuvre with aileron to slow or stop the rotation and obtain your exit to the position required by the end position of the move.

If you watch some of the Patty Wagstaff videos you see she slams the stick into the corner depending on the type and direction she wants. Its very hard to see is she breaks before inducing the roll.

However I find it darned hard to define some snaps in some IMAC events because they are blisteringly fast and if you blink you wont see the departure, plus the line often is not broken. By broken I mean the departure from normal flight to the exit all appear to be on the exact same line and for that to occur it is a wobbly roll to me and not a true snap. With a model I find it hard to actually do a decent sort of snap and retain the exact line you had on entry. Plus I beleive an offset from the entry line is not deductable if the line is maintained at say 45 degrees. So long as the 45 is maintained the offset does not impinge on the score. (Theoretically speaking anyway)

Then to make it even harder take some of the biplanes flying these days. Its almost impossible to get the tail to break no matter how hard you jump on it and they roll on a string line.

So if your judging a snap manouvre does the tail have to break first or can the departure from the line and the roll start simulteaneously.

TAS was adamant the longitudinal line must be broken before the roll commenced.

Is that the way it must be or is there another interpretation.
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Old 11-18-2008, 11:18 PM
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Re: The perfect Snap, El Snap perfecto??

I really had no idea snaps were so complicated. If I competed I suppose I would. I'm interested because my Yak goes so deep it IS a barrel roll. Trying to find out how to make it snap. Every other plane I've had snaps quick and it is all about exit back to the original flight path.

I'm still trying to learn though. Going to the Sim for a while.
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Old 11-19-2008, 12:45 AM
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Re: The perfect Snap, El Snap perfecto??

I think the "rule" that a pitch departure must be presented prior to rotation is a crutch for judges that can't see th plane very well or can't otherwise determine if the snap was positive, negative, or even a snap at all.
It seems simple to me - in a positive snap, the tail makes a circle where the rudder is on the inside of the circle and on a negative the rudder is on the outside of the circle. Then, to determine if it is even any kind of snap look at the axis of rotation - if it rotates about any point other than the aircraft's center of gravity then it is not a snap. It is either a barrel roll or the result of the wrong rudder input.
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Old 11-19-2008, 01:46 AM
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Re: The perfect Snap, El Snap perfecto??

To me it is a relatively easy task to judge a snap. It is the pilots job to show the two elements as per the rules for the snap to be scored ie. Pitch departure in the correct direction and auto rotation. When I am judging if the very first thought in my mind is "that didnt break" or "that didnt autorotate" then it gets a zero. I find some judges overcomplicate it and start second guessing themselves. I have judged some pretty good pilots (Frazer Briggs, Chris Brislin Jason Shulman and others) and seen all types of snaps, even handed out zero's to them for the ones that just wernt there.
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Old 11-19-2008, 07:08 PM
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Re: The perfect Snap, El Snap perfecto??

Snaps have always been a great discussion. I've heard that the late great Leo Loudenslager once said, 'A perfect snap roll is either a 10 or a zero'. Pretty interesting statement and it applies to models too.
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Old 11-19-2008, 07:34 PM
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Re: The perfect Snap, El Snap perfecto??

Quote:
Originally Posted by Kiwi View Post
Scott, Mith, John, Bruno and everyone else who is partaking in this thread.

I suppose my point is while full scales use aileron in a snap a technically perfect snap would be an elevator - rudder manoeuvre with aileron to slow or stop the rotation and obtain your exit to the position required by the end position of the move.

If you watch some of the Patty Wagstaff videos you see she slams the stick into the corner depending on the type and direction she wants. Its very hard to see is she breaks before inducing the roll.

However I find it darned hard to define some snaps in some IMAC events because they are blisteringly fast and if you blink you wont see the departure, plus the line often is not broken. By broken I mean the departure from normal flight to the exit all appear to be on the exact same line and for that to occur it is a wobbly roll to me and not a true snap. With a model I find it hard to actually do a decent sort of snap and retain the exact line you had on entry. Plus I beleive an offset from the entry line is not deductable if the line is maintained at say 45 degrees. So long as the 45 is maintained the offset does not impinge on the score. (Theoretically speaking anyway)

Then to make it even harder take some of the biplanes flying these days. Its almost impossible to get the tail to break no matter how hard you jump on it and they roll on a string line.

So if your judging a snap manouvre does the tail have to break first or can the departure from the line and the roll start simulteaneously.

TAS was adamant the longitudinal line must be broken before the roll commenced.

Is that the way it must be or is there another interpretation.

I have seen Pattern Planes do snaps that looked like wobbly rolls to me... but I think (but I ain't positive) that in F3A... departures from the initial path are downscored....

I know what "Looks Good To Me" in a snap... a big Pitch with a roll starting after the pitch but not necessarily before the full departure... and the roll axis looks like a line between the CG and the top of the rudder (positive).
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Old 11-19-2008, 09:02 PM
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Re: The perfect Snap, El Snap perfecto??

All of you guys are talking balony! I swear take advantage of SNAP A SAURUS' advice. ITs real good. Thats why he is SNAP A SAURUS!
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Old 11-20-2009, 07:03 PM
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Re: The perfect Snap, El Snap perfecto??

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I'm here, obviously the subject is THE PERFECT SNAP.
Here is my perfect snap definition, apply full power with a little up elevator, once the plane breaks ground few inches apply full up, full rudder and full aileron and yell SNAP A SAURUS BADASS, now that's a perfect snap, kids don't try this at an IMAC competition because it will get you a Zero.
BINGO......WINNER!!
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Old 11-20-2009, 07:04 PM
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Re: The perfect Snap, El Snap perfecto??

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BINGO......WINNER!!
Craven, how do you Know??
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Old 11-20-2009, 07:10 PM
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Re: The perfect Snap, El Snap perfecto??

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Craven, how do you Know??
Cuz I did your perfect snap and got a big ZERO in an IMAC contest.

The snap as you describe was definitely a "10".
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Old 11-20-2009, 07:35 PM
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Re: The perfect Snap, El Snap perfecto??

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Cuz I did your perfect snap and got a big ZERO in an IMAC contest.

The snap as you describe was definitely a "10".
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Old 11-20-2009, 08:03 PM
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Re: The perfect Snap, El Snap perfecto??

Far too many flyers get hung up with full scale comparisons .
All requirements are laid out in the IMAC rules guide , and that also
includes giving zeros for the prescribed manoeuvres .

As said 1 Pitch departure and 2 autotation rotation are the basic
requirements needed , after that its just how well it is done , i.e.
start and stop position .

Thats all IMAC but the perfect snap has to be a
1 1/2 negative from inverted to upright . It should be how you signal
to the judges that you have finished your sequence , Better still it should
also be how you signal the start as well .

1 1/2 pos snap is ok but its just not as cool .


P.S. I am the state CD in my local area and dont try this at my comps .


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