I thought I would get the varied opinions from folks on this board regarding this seemingly simple maneuver. Since people from all over the FAI universe read this discussion board, we should get a fair sampling of the global interpretation of this maneuver.

I have heard two interpretations of this maneuver: 1) the half outside loop portion of the Reverse Split S begins at the instant the wings have reached the level attitude during the 2/4 point. That is, there is no visible pause after completion of the second 1/4 roll.
2) the 2/4 point roll is not complete until the wings have been level for a duration which would be equal to the first point of the 2/4 point roll.

Which is correct and why? I ask because the rules seem somewhat fuzzy. They state : "From upright, perform 2 points of a 4-pt roll, and push immediately to a half outside loop" and also "In the Immelmann turn and split S manoeuvres and variations, the half roll, snap-roll, point-roll, or full roll should be performed immediately after or before the half loop as required by the particular manoeuvre. A visible line in between the two components must downgrade the manoeuvre by 2 points. Similarly, if the half roll, snap-roll, point-roll, or full roll is performed too early, the manoeuvre should be downgraded, using the 1 point/15 degree rule".

Well, what is the completion of the 2/4 point maneuver? Wings level, or after segment length equal to first point? If interpretation 1) is correct then it seems the maneuver should be described as two 1/4 rolls, not a 2/4 point roll. If 2) is correct then it seems the rules should clarify that.

Now I will sit back and read the ensuing thread. By the way, I see merits in both interpretations but don't really care which way is correct as long as we are consistent.

Shannah,

The FAI 2008 Sporting Code is very clear as to when the loop segment begins relative to the 2/4 roll and roll for Manuver P-09.01...

The following was copied from the 2008 Sporting Code.

P-09.01 Reverse Split S and Split S Combo, 2/4-pt roll first, full roll second, inverted exit: From
upright, perform 2 points of a 4-pt roll, and push immediately to a half outside loop. Perform a full
roll, followed immediately by a half outside loop, to exit inverted.
Judging notes:


The outside half loops must follow immediately after the 2/4-pt roll and roll.


The length of the upper horizontal line (including roll) is equal to the diameter of the half loops.
The geometric shape is that of a Double Immelmann.

Thanks,

I included that rule statement in my post as an example of the lack of clarity. Specifically, when is the 2/4 point roll complete? Is it when the wings are level, or is it after the wings have been level for the same amount of time that they were in knife edge?

Seeing as they reference the Double Immelmann in the description, I would say it is flown like the Double Immelmann. Right as wings are level the loops are started.

In the Sporting Code section 5B.7.7 further explains the general judging criteria for Loops/Roll Combinations.

Here's the criteria for Immelmann and Split S type maneuvers: (copied from the 2008 sporting code)

"There are, however, some judging criteria which should be explained further. In the Immelmann
turn and split S manoeuvres and variations, the half roll, snap-roll, point-roll, or full roll should be
performed immediately after or before the half loop as required by the particular manoeuvre. A
visible line in between the two components must downgrade the manoeuvre by 2 points. Similarly,
if the half roll, snap-roll, point-roll, or full roll is performed too early, the manoeuvre should be
downgraded, using the 1 point/15 degree rule."

Immediately after implies at completion of the rolling element. Therefore there is no line drawn after wings level.

Thanks.

That's how I've been doing it, but I see the validity of the other viewpoint. I just want to be certain that we are interpreting this like the rest of the world.

*Note to self: Fly perfect in front of Glen*

Now you know how I feel when I see you in the judges chair...[:@]

Kinda funny Steve.
I brought that Q back here to the guys up north after the contest down south this weekend.. In the Fai rules it states Point-rolls within a manoeuvre must have the same roll rate, and the points must be of equal duration on each point.
So this is where it's confusing. Where is the second point on a 2 of 4, and how does it apply to a immelman. The ama rules are pretty clear about it saying that the Immelmann - Split S rules overrule the roll rule..
Maybe it should be called a 1 of 4 rolling to inverted.. lol.. Maybe they should just make it a half roll..

I agree though, should be when wings are established as a defined level in a Split S or Imm..

In Masters ( I know this is ama) but look at the 2 of 4 split s.. We pull as soon as wings are level after establishing wings inverted level..

Chris

If, as suggested, the first outside loop should be commenced immediately after the wings are level, then the descrition of the manoeuvre is extremely misleading.

A much less confusing description would be, Knife Edge first, Full Roll second. [No reason why the duration of the Knife Edge and the Full Roll should not be stated as being equal].

In the minds of many pilots, a 2/4 roll is not complete until the inverted section of the roll (Point 2), is flown for a duration equalling the duration of the Knife Edge Section (Point 1). For example, if a manoeuvre was described as "2/4 Roll with 1/2 Roll Opposite" , would any pilot dream of starting the 1/2 Roll opposite just as soon as the model became inverted? I think not.

I respect the opinions of experienced Judges, but I also understand why so much confusion has been caused!

Bob

Lot's of interpretations. It get's confusing.

I think this would only apply when you are continuing to the reverse 2/4 point i.e. all 4 points should be of equal duration, centered, and (preferably ) with equal lines flown before and after.

Even with the 2/4 in the stall turn it doesn't apply as the 2/4 should be centered in the up-line between the base line and the stall point. It doesn't say anything about the line between the 2nd point and the stall turn being the same duration as the line between the 1st and 2nd point roll (is this correct?? . . or am I confused tooooo [sm=confused_smile.gif]).

It appears that myself and everyone I have seen, is flying it as Glen described . . pushing immediately to the half loop as the wings draw level.

JB

Jeff,

I have added to my Post #10, by referring to the example of a "2/4 Roll first, followed by a 1/2 Roll opposite".

Hopefully this will provide a clearer explanation of the cause for the confusion.

Bob

I can see . . but maybe if it said "2/4 roll first, IMMEDIATELY followed by a 1/2 roll opposite" ??? Then I would stop at the 2/4 point then immediatey do a 1/2 roll . . like it says (right or wrong?)

I am sure judges at local comps interperate differently as well . . . might explain one of the reasons we can get a 7 from one judge and a 4 from another ? (you can tell I'm a VERY average pilot )

Cheers, JB

Different interpretations of the elements of point rolls have been around for a long time. They stem from poor word smithing of the descriptions over time that has provided focus on the "point". Most will agree that, actually, all point rolls are about some number of equal roll rotations with equal pause between rolling elements, and this is generally how point rolls are flown and judged. Using that wording in the description of a point roll would minimize confusion.

Another consideration is that rolls begin when the wings leave the entry plane of flight and end when the prescribed number of degrees of rotation is complete. Pretty simple to grasp for one roll - put a straight line entry and exit of the minimuim distance (no need to be equal) and you have it. Similar logic applies to point rolls - roll X total degrees in some number of increments, with equal pause between increments and it's over at the completion of the total number of degrees.

For example - a 4pt. Roll is about four 90 degree rolling elements with an equal pause between rolls. The key word is pause "between" elements - usually defined as a "point" - there's no between after the last roll element - the thing's over when 360 degrees of rotation are complete.

So- apply this to a 2 of 4 Reverse Split S and you have two 90 degree roll elements of a 4pt Roll with the pause between roll elements - the roll portion is over after a total of 180 degrees rotation (no point after) and time for the loop element.

Earl,
Where is the center of that 4 PT roll.

Bill

I see merit in all of the views expressed above, and therein lies the problem. I am not at all surprised that Shannah felt compelled to ask the question.

I still take the view that the original description could easily have been improved. The fact that the manoeuvre is still the subject of discussion, 6 months into the new season, is testament to that. If the following 5 words in bold had been added to the original description, all of the confusion would have been removed. “… Perform 2 points of a 4 Point Roll and, after the wings become horizontal, push immediately to a half outside loop………”

The address at the end of this post links into the Web Page of Derk van der Vecht of Holland, one of Europe’s top F3A pilots. Half way down the left hand side of the page, you will see a link to a superb video of Derk flying an excellent demonstration of PO9. In Manoeuvre No 1, you will note that after Derk completes the 2nd point of his roll to become inverted, he pauses for a time equal to the duration of his knife edge flight before pushing upwards into his ½ Outside Loop.

If the description of the manoeuvre causes someone of Derk’s experience to misinterpret it, then the description needs to be improved!

Bob

http://translate.google.co.uk/transl...echt%26hl%3Den

Video in question is “Video F3a PO9 (info + K Factor)

Bill

Exactly half way between the beginning and the end.

Bill,

If I may, page 16 of the P09 PowerPoint presentation located on the NSRCA site ([link=http://nsrca.us/documents/judging/currentfaischedules/PPT_P09.pdf]P09 PowerPoint[/link]) does a nice job of showing center for the reverse 4-pt. Center is portrayed as the up-right flight path or 2nd point hesitation centered over the pole.

There is one thing the FAI rules say and it is very clear, when they say inmediatly they mean it, when there is a pause, they also call for it, like on the three consecutive rolls, they say, the pause between rolls are very brief and this means there is a pause there, on the opposite rolls they say the pause in between the rolls are the same duration of the rolls, again the same applies.

So knowing this, also judging notes are given, all the information is there, is you want to make a pause then do it, if they downgrade the manouver or not is a gamble, if you do it inmediatly, for sure they will not downgrade the manouver, and if a judge(guy that talks to other judges ) tells you to do it inmediatly, I suggest you do it, I haven't seen a pilot that can win an argument with a judge yet.

Just the way I interpret the rules.

Regards

That is interesting that you use this example. I started flying this maneuver with equal pause because I watched this video. This is my first year back flying FAI after quite a long layoff and I used this as a reference. Then, at my second local contest we had a discussion prior to the start of the contest where the clarification was made to judges that there should be no pause after wings have rolled level. It was a simple adjustment to make when flying, and it was nice to know the criteria that were being used for scoring. Hopefully, it will always be interpreted in a consistent fashion.

I agree, Chris, that AMA has always been interpreted as no delay after the roll. Even IMAC uses that criteria. However, since I dredged up this matter I went back to the AMA rulebook and looked and it isn't as explicit as I had thought.

I asked this exact question to an experienced judge here in the UK at one of our comps on Sunday, the reply was that after the wings become horizontal, push immediately to a half outside loop………” I was told by the experienced judge that this is the interpretation by the chief judge here in the UK.

Regards,

Matt

I have not read all the posts on this but I am of the view that you push as soon as the wings are level.

I asked a similar question regarding the outside loop with the 4 point roll in the bottom 180*. JAS confirmed that you start rolling at the 1/4 loop and finish rolling at the 3/4 loop i.e. you do not have the pause ending at the 3/4 loop.

On this basis a 4 point roll is really 4 quarter rolls with 3 pauses (I guess like a 4 post fence with 3 gaps); and so 2 of a 4 point roll is 2 quarter rolls with one pause.

You will now get into arguments as to where the centre of a 4 point roll is - surely the middle of the inverted.

B

We've had that argument Brandon.. lol..

Now where is the center of a 2 of 4 though? The middle of the knife? We should all know that for upline and downline 2 of 4's centering..

Chris

OK, how about the 3 rolls in opposite directions. The FAI rulebook says:

"The roll must have a crisp and well-defined start and stop. If a start or stop is badly defined, 1 point is subtracted for each."

What if there is no defined stop after each roll element, ie. immediately reverse direction at wings level almost like a bounce?

The PPT for P09.03 says "Pause between rolls is very brief."

I am asking as I have seen it flown both ways, a brief hesitation at wings level and a bounce at wings level (no pause).

Ray