My thoughts on the New Clover

[Bruce Shipp]

Having not been to a contest since this new rule took effect I am curious, what type of entry are most folks using?

Is it a hard 90, wing over type entry, a quarter loop, or something in between?

Thanks,

Bruce

[Derek Barry]

For the record:  "one busy-body"  =  Keith Trostle

Also for the record:  I do not think that I ever "quibbled" about the "correct altitude for level flight".

Regarding the four leaf clover - let's go back a few years.

In the late 50's, George Aldrich essentially created the pattern that we have since flown.  In that pattern he wrote the rule for the four leaf clover.  As far as we know, he estimated the loops would have a diameter of something smaller that the 45^o loops and elevations defined for the rest of the pattern.    (The FAI adopted our AMA pattern into their rules around 1960.)  I am not sure what diameter George chose for the diameters of the four loops in the clover.  The '72 rule book shows the entry to be at 45^o and the tops of the two top loops were to be at "3-7 feet below the 90^o point over the flyer's head."  The diameter of those loops were not defined at that time.  This description remained in effect until the 78-79 rule book where the entry point was to be at the 38^o elevation and the tops of the two top loops were to be "3.9 feet from the vertical plane through the circle center".  This description was essentially interpreted by pilots to mean the loops were to have a diameter of 38^o.  With 38^o diameter loops, the tops of the two top loops could not possibly get close the that "3.9 feet from the vertical plane through the circle center".  Instead, the four leaf clover was essentially flown in front of the pilots face where the tops of the two top loops did not come close to the "vertical plane through the circle center" as specified at that time.  The Clover essentially appeared as two sets of 38^o loops side-by-side, each with each set having one loop on top of the other.  (In my experience, many pilots, even good experienced pilots, still fly their four leaf clover too small to this day.)

This description of the clover with the 38^o entry point remained in effect until about 2004.  I was not a member of the Contest Board at that time.  However, I knew that the entry and the 38^o diameter for the four loops of the clover could not fill the half hemisphere as described by the rule book where the tops of the two top loops were to be tangent to the "vertical plane through the circle center" (as defined at that time) coupled with the requirement all the loops were to be round and tangent to each other.  I asked Pete Soule to look at the description of the four leaf clover and define what the diameter of those loops should be and what the entry level of the maneuver should be.  Pete Soule is an aerospace engineer in Southern California that I have had the privilege to know and to have met with him regularly at that time.  He prepared a report in July, 2004 that determined the size of the loops if they were to be tangent to each other and tangent to the 4-6 feet normal flight level altitude as well as tangent to the vertical plane through the center of the circle.  Those loops were to be 42^o in diameter and the entry level was to be at the 42^o constant elevation given the manner on how the maneuver was to be initiated at that time.

Based on the Soule calculations, a proposal was initiated at that time and accepted by the Contest Board that defined the clover with 42^o diameter loops, that they were to all be tangent to each other, that the bottoms were to be tangent to the 4-6 foot altitude, that the top two loops were to be tangent to the vertical plane through the center of the circle and that the center of the maneuver was to be a constant 42^o elevation.  The proposal was adopted at that time (around 2005 or 2006) and has remained essentially unchanged until this year.

(A few years later, the FAI changed their rules which essentially adopted our AMA rules change made to our four leaf clover.)

It was after the FAI adopted our change to the clover that Keith Renecle of South Africa generated his 3-dimensional simulations of what the whole pattern looked like on the hemisphere where our pattern is flown.  It quickly became apparent that something was wrong with the description of the clover.  The real problem was the specification that the center of the maneuver was defined by the constant 42^o elevation.  With this constant elevation, either the loops could not be round or they could not all be tangent to each other and still meet the loops' tangency requirements at the top and bottom of the maneuver.  Over the years, there was considerable discussion in Europe on this dichotomy.   Those discussions eventually led the FAI to change their description of the clover several years ago which eliminated the constant 42^o elevation through the center of the circle.

Soule later modified his study to show that the path through the center of the maneuver could not be at a constant 42^o elevation but would be on the great circle path on a plane at 45^o through the center of the circle and that the tangent points between the top and bottom loops would be at the 42^o elevation, just as shown in the Renecle simulation.

I generated a proposal to the Contest Board about 3 years ago to initiate the change so that the maneuver could be flown as described.  That initial basic proposal was withdrawn because it had errors.  A revised proposal was submitted more than a year ago and was posted on the AMA web site for most of last year.  This proposal was the subject of many comments on this Stunt Hangar forum for several years.  This change eliminates the constant 42^o elevation through the center of the circle which made it impossible to fly the maneuver as it was then described.  With the "upright" and "inverted" flight paths through the center of the maneuver, all of the tangency and round loop requirements can be met.  The upright and inverted flight paths through the center of the maneuver are no longer required to be at a constant elevation but rather they are actually on a great circle path on a plane that is at 45^o from the center of the circle.  These are great circle paths, just as are the vertical paths through the center of the circle.  Rather than writing that 45^o elevated plane into the rule book, the wording explains that the paths be upright and inverted through the center of the circle and does not even suggest that those paths are to be at a constant elevation.  This proposal was approved last Winter at the close of the last rule change cycle and is now in the 2022-2023 rule book.

The new FAI rule allows the entry to be either from normal level flight or at the "center" of the maneuver.  We did not allow for this option because to properly maintain the tangency requirement, the model cannot be in level flight at the initiation of the maneuver for the option to start the maneuver at the "center" of the maneuver.  Instead, it would need to be on a path on that 45^o plane through the center of the circle.  There was also some discussion by a few board members on how the entry should be defined.  One option was to have the start from the normal flight level with a sharp turn (as if putting a stem on the maneuver).  Instead, it was decided to put the judging start and stop points to be at the 45^o elevation which also happens to be crossover point for the vertical and inverted flight paths through the center of the circle which is also the very center of the clover.  The initial turn to a vertical flight path is not defined by the new rule book.  The way the rule is written, the pilot has a choice as to how to establish the vertical path at the start of the maneuver.  In addition, the new rule also allows the pilot to recover from the maneuver before flying through the top of the circle directly into the wind when there is a severe wind. 

Another way to explain the need to change the rule is that until this change, the prior rule that required all loops to be round, that they all be tangent to each other, that the bottom two loops be tangent to the normal level flight path, that the top two loops be tangent to the vertical plane through the center of the circle, AND that the horizontal flight path through the center of the circle was to be a constant altitude (albeit the earlier 45^o, then the 38^o or the more recent 42^o), the maneuver could not be flown.  In other words, it was impossible to fly a perfect maneuver because it was impossible to do as the description was flawed.  I do not think a maneuver description should be so faulty that it would be impossible to perform.  The real problem with any of the previous attempts to define the four leaf clover was the requirement for a constant elevation flight path through the middle of the maneuver.  Or, it would be possible to leave the constant elevation requirement in, but then eliminate the requirements that the loops be round and the same size.  If that choice were to have been made, the maneuver would no longer be symmetrical.

One more thing.  The previous description for the clover required one 360^o loop and three 270^o loops.  Now, the clover appears as four 270^o loops which, in my conservative unbiased opinion, gives a more symmetrical appearance.

Note to Derek:  This proposal was on the AMA website for over two years.  There has been discussion on this matter on this Stunt Hangar for longer than that.  Also, for the record, the final vote on this proposal was completed in September of last year, before you became a member of the Contest Board.  The vote among the 11 Board members was 10 for, 1 against the proposal.

(One note about Pete Soule.  He is/was well known in the Team Race community and was on the US F2C team several times.  He wrote the "Round and Round" control line column for Model Airplane News for several years.  He has written or co-authored several technical papers regarding control line airplanes.  He is a genuine rocket scientist.)

Keith Trostle
Chairman
AMA Control Line Aerobatics Contest Board

Thank you for providing everyone the full history of the Clover. I would like to note, that I didn't like the change from 38° to 42° either. I still prefer the original, tight clover.


 I admitted that I hadn't actively monitored the rules forum in the past few years. I also said that my predecessor told me when he asked me to take his position that he had voted in favor of the new rule, and I had no issue with the procedure, or the way he voted. My only complaint was that I wasn't contacted about the rule change. In my capacity as a Rep for the Contest Board,  I will make certain to contact all the competitors in my district to get their input on rule proposals. I don't think people should have to actively search for rule changes on the AMA site or this forum. Their representative should contact them about all serious changes,  especially when the pattern we all fly is concerned.

I also believe that all of your justifications for proposing this change are strictly academic arguments.  Never in the history of stunt has any pilot had a problem flying or judge judging any of the 3 versions of the clover. Sure, there has been much debate online about it, but in practice it is simply not a real issue. The judging of our event is entirely subjective,  so all your calculations and determinations, mean nothing in the real world. They are simply guidelines.  This is the basis for my feelings about the rule change. I am never a fan of change, just for the sake of change, especially when it reduces the skill level required to compete in this event.

Sure, it's a trivial change, and will certainly boost my score, but it was absolutely unnecessary.

Again, these are my opinions,  and you are free to disagree with me.

Kindest regards,

Derek

[Dan McEntee]

Having not been to a contest since this new rule took effect I am curious, what type of entry are most folks using?

Is it a hard 90, wing over type entry, a quarter loop, or something in between?

Thanks,

Bruce

   The entry is from level flight, and then a turn up as if doing a wing over, and then into the first loop. Judging is supposed to start at the would be intersection of the four loops, and stops after passing through the intersection for t5he last time. Go to the rules section on the AMA website for the complete description. I myself like the new entry. The clover was the one maneuver that I couldn't "see" when I went into it as I described in the "Where Do You Look" thread. Looking up at the model at the old entry point just didn't give me any perception of where I was until I got past the intersection and did the first outside loop. Now, when I pull up to enter, I have something in my mind to go by, and I would think so will a lot of others. Having everything relate t level flight, 45 degrees or directly overhead makes more sense to me also, even though I have to bend my old back some more!!
  Type at you later,
    Dan McEntee

[Trostle]

Thank you for providing everyone the full history of the Clover. I would like to note, that I didn't like the change from 38° to 42° either. I still prefer the original, tight clover.

(Clip)
 
 I am never a fan of change, just for the sake of change, especially when it reduces the skill level required to compete in this event.

Kindest regards,

Derek

Hi Derek,

Your comment that you prefer the 38^o loops of the four leaf to the 42^oloops is interesting.  Yes, "in the day", pilots would start the four leaf at an elevation at something like 38^o, at least something noticeably less than 45^o.  That meant the top of the maneuver would be somewhere in the vicinity of 76^o which is a long way from the top of the circle.  Yet the rule from that period stated that "the top shall be tangent to the vertical plane through the circle center."  The rule was flawed for many years.

Some pilots disregarded the rule about getting the tops of the loops even near that "vertical plane through the circle center" and planted the four leaf in front of their faces.  I have watched you fly over the years, even as a Junior, and do not recall that you flew the four leaf with the constrained 38^o diameter loops. I think you had (have) a very good coach.

As I mentioned in my first post above, many pilots still put the maneuver in front of them and do not get close to have the top two loops tangent to the vertical plane through the center of the circle.

What is interesting to me in my observations and the times that I have judged.  I am convinced that certain world class pilots actually did not fly a constant elevation through the middle of the four leaf.  Rather, they would fly a path closer to a great circle path rather than a constant elevation.  They do this with the tops of the square maneuvers as well.  It looks better to the judges.

You suggest that this change to the four leaf clover description "reduces the skill level required to compete in this event".  Could you please explain why you made that statement.

One thing I like about the vertical entry for the maneuver, it makes it easier for the judges to establish what the pilot has flown to be the vertical path through the center of the maneuver.  I do not see how that reduces the skill level for the pilot "to compete in this event".  The pilot still has to follow that vertical path two more times before completing the maneuver.

Keith

[john e. holliday]

Are the judges really worried about the degrees that the maneuver is supposed to do or are they looking at what looks like a four leaf clover with all the different line lengths and size airplanes used?

[Trostle]

Are the judges really worried about the degrees that the maneuver is supposed to do or are they looking at what looks like a four leaf clover with all the different line lengths and size airplanes used?

Hi Doc,

No, the judges are not concerned about degrees that define the size of the loops.  Regarding the Clover:  What they should be looking for are roundness of each of the the loops, the bottoms of the bottom two loops being tangent at the normal flight altitude, that the loops do not overlap each other, that the tops of the two top loops are tangent to that vertical plane through the center of the circle (above the pilot's shoulders, not in front of his face), that the vertical paths though the center of the maneuver are vertical, straight and are on the same path, and that the inverted and upright paths through the center of the maneuver are on the same path.  The loops should not overlap the great circle paths of the three vertical climbs and the upright and inverted paths in the middle of the maneuver.  The judges guide explains this more clearly and in more detail.  If the maneuver meets these criteria, it makes no difference of the size of the airplane or the length of the lines.

The 42^o loops of the clover are mentioned primarily to indicate that the clover loops are smaller than the 45^o round loops required in all of the other round maneuvers.

Now we know why judges get paid so much for what they do.

Keith

[MikeyPratt]

Keith & All,
To my way of thinking changing the four-leaf clover is not so bad, after three flights I could do a reasonable looking fore leaf.  However, I don’t really think it needed to be changed in the first place, I did take awhile to get used to doing it that way.  I still have the urge to climb to 42 degrees to start the maneuver, but it’s getting better after a three dozen flights or so.  I understand the reason for changing it to better describe the maneuver, but we have been doing this way for so long now.

What this reminds me of is Al’s argument of when does the engine quit at the 79 Nat’s (because he had a dykes ring that would windmill longer than other engines).  It was at that point Ted Fancher & Les McDonald told me to just land like normal and don’t worry about.

Mikey

[Brett Buck]

What this reminds me of is Al’s argument of when does the engine quit at the 79 Nat’s (because he had a dykes ring that would windmill longer than other engines).  It was at that point Ted Fancher & Les McDonald told me to just land like normal and don’t worry about.

   It's very important to listen to the right people - and people don't get any righter than those two! 

   My advice to people is always about trying to separate out common sense from pedantry. There are many stunt people who will happily argue over the stunt equivalent of how many angels can dance on the head of a pin, endlessly, because the event filters for perfectionists - myself very much included, and it is very easy to lose your perspective.  Far be it for me to tell people how to enjoy the hobby, but you have to avoid falling in the trap of questions like "what does 'square' mean?" unless it actually matters.

     Brett

[Steve Helmick]

I was expecting to read Brett say "The French changed the F2B rule first". It does make sense that we should change the Clover entry to be the same as FAI, so our future team members won't have to change just for a WC and potentially make a mistake that costs them a WC.   

As for myself, I've yet to either see or do a Clover with the new entry, but don't see how it could make the maneuver ugly...probably would make it prettier, I think. Easier to judge, probably easier to fly also. Like the entry to the OH8 (or OH9), there is no need to hammer the entry corner, so don't do that!  Steve

[John Lindberg]

When does this new rule take effect, if at all? Thank you, John Lindberg.

[Trostle]

When does this new rule take effect, if at all? Thank you, John Lindberg.

As explained several times on this forum, the "new rule" became effective on January 1, 2022.

Keith

[Brett Buck]

I was expecting to read Brett say "The French changed the F2B rule first".

      If that was the sole reason, it would be a very bad one. However, with respect to Derek's opinion, I don't see it as much of a change or particularly important to do it either way. After trying it a few times last year, I kind of like it. But I also wouldn't care very much if it got put back, either, which I expect to be proposed very soon, if it hasn't already. Again, to me, for my own money, it's not enough to get worked up about either way.

    I am again amazed at the fact that many people were unaware of the change at all, but it happens every cycle.

     Brett

[John Lindberg]

As explained several times on this forum, the "new rule" became effective on January 1, 2022.

Keith

Ok, thanks.

[Trostle]

Ok, thanks.

You are welcome.

The proposed change was made to the AMA more than 1 1/2 years ago and has been the subject on this forum since before that time.

Keith

[Doug Moon]

You are welcome.

The proposed change was made to the AMA more than 1 1/2 years ago and has been the subject on this forum since before that time.

Keith

Hello Keith,

I sent you a PM asking a question. It wasn't about this topic.

Thank you
Doug

[Curt D Contrata]

I have been on the sidelines for a while, but this reminds me of a conversation I had with Gene Martine at the end of top 20 day in maybe 1999 or 2000. My thoughts back then were that the clover was being flown wrong.

I have agreed with many points made here, and while I like the idea of changing the entry point, I see Derek’s point of this change making it easier to fly. My thought back years ago was to make the entry point diving down from the top by pulling up in front of the judges and making the bottom right, outside loop first.

Bottom right 3/4 outside loop from a dive through the center, then a 3/4 outside loop bottom left, then a 3/4 inside loop top right, then a 3/4 inside loop top left, with a 90 degree pull out from vertical to level flight.

If not a fan of outside bottom right followed by outside bottom left, it could be flown as bottom right, top left, bottom left, top right, dive to exit at level flight.

This is a moot point now especially since FAI adopted a change, but in my opinion this would likely be more difficult than what it is currently written and could look a bit better.

No dog in this fight, I am just an outsider at this point. I never liked how the traditional clover had a round loop at the top right but totally respected tradition.

Hope all of you are well,


Curt

[Trostle]

Hello Keith,

I sent you a PM asking a question. It wasn't about this topic.

Thank you
Doug

Doug,

Message sent two days ago.

Keith

[Doug Moon]

Doug,

Message sent two days ago.

Keith

I resent it yesterday.

Doug

[Steve Fitton]

Where is the thread on how to actually fly the new clover? I have flown dozens and dozens of flights the last few weeks, and the new clover is still killing me....

[Motorman]

You just do a down wind wing over and when you get a little past 45 degrees you do your first loop then the rest is the same as before. What part are you having trouble with?


Motorman

[Dan McEntee]

Where is the thread on how to actually fly the new clover? I have flown dozens and dozens of flights the last few weeks, and the new clover is still killing me....

  And accurate description will be in the new rules book posted at the AMA web site. It's best to get it right from the horses mouth.

     https://www.modelaircraft.org/sites/default/files/CL%20Precision%20Aerobatics%202022-2023.pdf


 Type at you later,
  Dan McEntee

[Ken Culbertson]

A video would be nice.  I have several but my systems are down while I move my office.  For me the hardest part of the transition was remembering to not climb to 42 on the entry lap.

Ken

[fred cesquim]

My thoughts on the New Clover: ok, changed, let´s try. Done.

i had spend 3 decades flying c/l and took it seriously on last 2 years so it takes me about 30 years to learnt the clover, as soon as i did it, rules changed LOL
that´s life. I like the new one

[Steve Fitton]

You just do a down wind wing over and when you get a little past 45 degrees you do your first loop then the rest is the same as before. What part are you having trouble with?


Motorman

I think I am coming out of the vertical pitch into the maneuver either too high or too low *every single time* which results in either goofy shapes or a terrifyingly low pullout every time.

[Motorman]

You could go into that first loop a little high, won't hurt nothing, then when you come around, make sure to level out at a good height and that will set up the rest of the loops real nice. If you level out too low, just go around.

Motorman

[Jim Svitko]

I see no problem with the new clover.  I like it, from a maneuver entry point, and from a symmetry perspective.  Four 270 degree loops, and you enter from level flight.  All I need is much more practice.

For me, the old clover was rather tough.  Entering at the proper height (38 degrees? 42degrees?) was impossible for me.  I never got the first loop right.

I prefer to leave it alone now.  Everything seems to flow better with the new one, so why go back to the old one?  I know, not everyone will agree.

[john e. holliday]

I got to watch a few flights at Brodaks and it looked to me like the people were making it look easier than the old way.  The thought of climbing into the wind still terrifies me but I haven't flown a pattern in almost two years.

[Doug Moon]

I think I am coming out of the vertical pitch into the maneuver either too high or too low *every single time* which results in either goofy shapes or a terrifyingly low pullout every time.

I have now flown it many times. While at first glance it makes it easier to perform the maneuver as a whole. It also makes it easier to miss the first horizontal 45 degree pass high. And it will be GLARING!  It also makes it VERY easy for judges to see the intersections.  At the upper levels where scores get very close and flying gets very technical I think this could be harder in the end. That's just me thinking out loud....

[Ken Culbertson]

I got to watch a few flights at Brodaks and it looked to me like the people were making it look easier than the old way.  The thought of climbing into the wind still terrifies me but I haven't flown a pattern in almost two years.

A lot of very good fliers, maybe even most would hold that exit past direct overhead because the wingover exit was more "professional".  It was also not judged (unfortunately).  I used to subscribe to that but since coming back I have gone to the over the shoulder exit as soon as I know I am past the end point.  I am still doing it that way with the new clover but I think I am going to start exiting the same way you do the H8.  I empathize with Doug.  I just looked at a video of my first new clover since it became official.  Cute little thing.  Maybe we should consider putting the horizontal at 30 degrees.

Ken