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Another snap question... - 8/7/2006 10:14:44 PM   
3D Joy



Posts: 1061
Joined: 12/21/2002
From: , QC, CANADA
Status: offline 		As a contestant, I often end up judging lower classes. Last week I gave some zeroes to an advanced guy that snapped with the rudder in the wrong direction and agreed with the other judge that it was not a snap --> no autorotation... everything else was there but no autorotation. In fact the plane rolled at a slower pace than if no rudder was applied at all.

I was discussing of this with a full scale flyer that used to fly IAC competition and he told me I should not have zeroed those snaps. He said that we should look for some sort of cone shaped movement of the tail and that it should have been the case even if the rudder was not properly used.

Is he right ?
       Post #: 1

RE: Another snap question... - 8/7/2006 10:47:44 PM   
rcblimppro



Posts: 514
Joined: 2/9/2003
From: San Jose, CA, USA
Status: offline 		I am an Advanced class pilot and have attended an IMAC judging school. I am asked to sit in the judges chair at every contest I have attended in the last 5 years including twice at the SW IMAC Championships. Usually I am asked to judge the Unlimited guys but have judged all the classes. That being said, you were 100% correct in giving that pilot a zero. I have given zeros for the same thing on several occasions.



Shawn

(in reply to 3D Joy)
       Post #: 2

RE: Another snap question... - 8/8/2006 1:34:47 AM   
MikeEast



Posts: 3226
Joined: 10/18/2003
From: Nederland, TX, USA
Status: offline 		What is the criteria for discerning autorotation in IMAC? What tells you that there was no autorotation?

The reason I ask is becuase in pattern the "speed" of the rotation is not a judging critera although the AMA calls it "rapid autorotation". I just want to be able to differentiate. The criteria in pattern are a visible pitch break and simultaneous rapid autorotation. This is apparent after the break when you see both the nose and tail coning around the cg. If there is no visible coning, its a zero. If there is no nose break it is a severe downgrade in pattern.

For IMAC, I know there is a rulebook I can read (and have some), I am just curious what you guys out there judging are looking for and basing your scoring decisions on.

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Mike East
AMA793948
RCU Reviews
Moderator: 3D, IMAC and Pattern Forums.

(in reply to rcblimppro)
       Post #: 3

RE: Another snap question... - 8/8/2006 2:34:45 AM   
JB Rekit



Posts: 543
Joined: 3/1/2003
From: Magnolia, TX, USA
Status: offline 		A zero was correct. It would be almost impossible for it to actually break while using the wrong rudder as long as elevator was also applied in the right direction. That is the reason it rotated so much slower. It probably just did a slow corkscrew w/o actually stalling the wing.

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RE: Another snap question... - 8/8/2006 4:50:37 AM   
MikeEast



Posts: 3226
Joined: 10/18/2003
From: Nederland, TX, USA
Status: offline
quote:

ORIGINAL: 3D Joy

As a contestant, I often end up judging lower classes. Last week I gave some zeroes to an advanced guy that snapped with the rudder in the wrong direction and agreed with the other judge that it was not a snap --> no autorotation... everything else was there but no autorotation. In fact the plane rolled at a slower pace than if no rudder was applied at all.

I was discussing of this with a full scale flyer that used to fly IAC competition and he told me I should not have zeroed those snaps. He said that we should look for some sort of cone shaped movement of the tail and that it should have been the case even if the rudder was not properly used.

Is he right ?



What do you mean by "snapped with the rudder in the wrong direction" and how does that relate to whther or not the plane autorotates? Please explain. I am new to IMAC (but not new to sequence flying) and really want to understand what you are talking about so that I can apply it to how I execute a snap. I know that there are positive and negative snaps, and can execute both, but what difference does it make it the plane snaps positive or negative with left rudder or right rudder?

_____________________________

Mike East
AMA793948
RCU Reviews
Moderator: 3D, IMAC and Pattern Forums.

(in reply to 3D Joy)
       Post #: 5

RE: Another snap question... - 8/8/2006 4:59:26 AM   
rcblimppro



Posts: 514
Joined: 2/9/2003
From: San Jose, CA, USA
Status: offline
quote:

ORIGINAL: MikeEast


quote:

ORIGINAL: 3D Joy

As a contestant, I often end up judging lower classes. Last week I gave some zeroes to an advanced guy that snapped with the rudder in the wrong direction and agreed with the other judge that it was not a snap --> no autorotation... everything else was there but no autorotation. In fact the plane rolled at a slower pace than if no rudder was applied at all.

I was discussing of this with a full scale flyer that used to fly IAC competition and he told me I should not have zeroed those snaps. He said that we should look for some sort of cone shaped movement of the tail and that it should have been the case even if the rudder was not properly used.

Is he right ?



What do you mean by "snapped with the rudder in the wrong direction" and how does that relate to whther or not the plane autorotates? Please explain. I am new to IMAC (but not new to sequence flying) and really want to understand what you are talking about so that I can apply it to how I execute a snap. I know that there are positive and negative snaps, and can execute both, but what difference does it make it the plane snaps positive or negative with left rudder or right rudder?




Mike, when opposite rudder is applied the manuver is no longer a snap roll. The criteria for a snap is that the wing has to stall or in the case of our models must "appear" to stall (but that is another whole topic there). When opposite rudder is used the airplane flys through the roll and thus cannot be called a snap roll. The wrong manuver was flown so the figure gets a zero.


Shawn

(in reply to MikeEast)
       Post #: 6

RE: Another snap question... - 8/8/2006 5:25:30 AM   
wgeffon



Posts: 6376
Joined: 12/2/2001
From: Bloomington, IL, USA
Status: offline 		If it was a positive snap (Pull) what he did was a Shoulder Snap. Pull, left aileron and right rudder. Or, Pull, Right aileron and left rudder.
A zero in any case.
It will still Auto Rotate that way though.

If he was doing a negative snap opposite rudder from aileron is correct. No zero.

< Message edited by wgeffon -- 8/8/2006 5:26:27 AM >


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Wayne

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RE: Another snap question... - 8/8/2006 5:27:38 AM   
MikeEast



Posts: 3226
Joined: 10/18/2003
From: Nederland, TX, USA
Status: offline
quote:

ORIGINAL: wgeffon

If it was a positive snap (Pull) what he did was a Shoulder Snap. Pull, left aileron and right rudder. Or, Pull, Right aileron and left rudder.
A zero in any case.
It will still Auto Rotate that way though.

If he was doing a negative snap opposite rudder from aileron is correct. No zero.


Ok, that answers my question

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Mike East
AMA793948
RCU Reviews
Moderator: 3D, IMAC and Pattern Forums.

(in reply to wgeffon)
       Post #: 8

RE: Another snap question... - 8/8/2006 5:29:12 AM   
sknx



Posts: 162
Joined: 7/2/2004
From: Evanston, IL, USA
Status: offline 		I'm new to IMAC and I might get it wrong but I do not understand what means rudder in wrong direction and where you zero a flick. The regular snap roll is just elevator and rudder, no matter which direction. For a CW spinning prop and positive maneuver left rudder wil make the cone wider and faster, right rudder will tighten the cone but the autorotation it's slower. No matter the side, both are autorotational maneuvers. If ailerons are applayed with rudder, as far as I know, it's called accelerated snap roll.
Going back to judging, are you zero a snap if no ailerons are applyed or ailerons are reversed to rudder ?

10X

(in reply to 3D Joy)
       Post #: 9

RE: Another snap question... - 8/8/2006 12:03:09 PM   
3D Joy



Posts: 1061
Joined: 12/21/2002
From: , QC, CANADA
Status: offline 		Ok just to clarify my first statement.

It was a negative snap and the elevator was down and the rudder was applied at the same direction as the ailerons --> hence wrong direction. I do fly unlimited and had attended judging seminars in the past so I was pretty confident my zeroing of this snap was a good thing to do but being a guy that always listens to others that have more experience than me, especially this guy that used fly full scale competition which we are supposed to try to duplicate, I had to ask here... In fact we don't really try to duplicate full scale as we make snaps that don't look like snaps, but that's another story...

I was feeling bad as I zeroed this guy the Humpty bump in advanced for all sequences I judged and this happens to be the critical maneuver with the biggest K factor. That put him back by at least 3 positions in the rankings of that competition.

BTW, last weekend I tried to snap without ailerons at all. Looked much more like a full scale snap and while I was thinking it made a much too deep snap that almost stopped the plane, my friend told me it was almost deep enough for a full scale snap... That rendred my plane useless for the hammer head in unlimited where I have to make 1 1/2 neg snap on the upline; not enough power.

Thanks for your help guys!

(in reply to sknx)
       Post #: 10

RE: Another snap question... - 8/8/2006 2:56:27 PM   
v-snap



Posts: 949
Joined: 10/29/2002
From: brownsburg, IN, USA
Status: offline 		I love these conversations...I think I understand the initial question. The poor guy did an outside snap inplace of an inside snap..
Wayne never heard the term shoulder snap before. I know some full scale pilots would kick the opposite rudder to enter the lamchavak (easier said then spelled).
Now the response of "too deep of a snap with rudder only" lost me...If infact you stalled the wing it wouldn't be any deeper, one from the other. Now it may have slowed the rotation due to lack of aileron use at the onset and caused a slower airspeed at the recovery stage but I can't picture a deeper snap. Or maybe we are just now questioning what the high roll rate monoplanes introduced to the IAC world in the 90's "was it a snap or a roll????".
These discussions are much easier to picture at the flying field with a plane handy...

< Message edited by v-snap -- 8/8/2006 2:57:29 PM >

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RE: Another snap question... - 8/8/2006 4:36:22 PM   
3D Joy



Posts: 1061
Joined: 12/21/2002
From: , QC, CANADA
Status: offline
quote:

ORIGINAL: v-snap

Now the response of "too deep of a snap with rudder only" lost me...If infact you stalled the wing it wouldn't be any deeper, one from the other. Now it may have slowed the rotation due to lack of aileron use at the onset and caused a slower airspeed at the recovery stage but I can't picture a deeper snap. Or maybe we are just now questioning what the high roll rate monoplanes introduced to the IAC world in the 90's "was it a snap or a roll????".
These discussions are much easier to picture at the flying field with a plane handy...


OK to explain a little more. Maybe I use too much elevator for my snaps (I could improve that) but I also use ailerons in competition so the snap is fast enough and the plane does not have time to pitch up very much and I can manage to have speed left for the straight line that has to follow the snap. Now if I do exactly the same without ailerons, the plane has much more time to "pitch up" hence the fact that the snap looks deeper and as you mentioned, the snap takes more time to execute so the exit speed is much lower.

At a field with a plane handy as you said... Much simpler then!

(in reply to v-snap)
       Post #: 12

RE: Another snap question... - 8/8/2006 9:37:30 PM   
Silent-AV8R



Posts: 1824
Joined: 3/16/2004
From: SOCAL, CA, USA
Status: online 		In IMAC there are two things absolutely required for a snap roll:

1) the nose MUST depart the line of flight in the proper direction (towards the canopy in a positive snap, towards the wheels in a negative snap).

2) the plane MUST autorotate.

If EITHER one is absent, the maneuver gets a zero.

Autorotation is a result of the wing being partially stalled (usually one wing) and it causes a rotation that is generally faster than could be accomplished by the use of the controls alone. Be watchful for the crafty pilot that will try to fool you with a little flick of the nose and then a REALLY fast axial roll instead of autorotation. Autorotation is very hard to define, but once you have seen it there is no mistaking it for a fast axial roll.

As a judge it matters not one little bit what controls are used, how much or in what direction. ALL you are doing is judging what the plane does. The figure in the original post would have been zeroed by me as well. It did not autorotate. I don't care if it was "wrong" rudder or whatever. The pilot failed to present the required components for a snap to get scored. Period.

There is a very nice section of a thing I call "The Rulebook" that covers this. It is worth a look!!.

Bill Malvey
Chairman IMAC Rules and Standards Committee

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RE: Another snap question... - 8/9/2006 5:37:27 AM   
highK


 

Posts: 43
Joined: 7/30/2006
From: perris, CA, USA
Status: offline 		bill, why do you complicate things with references to the rules? all that does is add to the confusion. it makes more sense to solicity input from the iac and pattern guys and anyone on RCU with an opinion.

guys...the rules are clear, published, and easily accessed. What pattern or IAC has to say on the matter is meaningless, although that is easier said than accepted. A judge owes it to the competitors to be well versed on the rules, and so far, bill is the only one to cite the rules to support his answer.


a former chairman of the imac seq committee

(in reply to Silent-AV8R)
       Post #: 14

RE: Another snap question... - 8/11/2006 10:05:34 PM   
amjflyer