The Clover

Articles from time to time in SN tells us the common mistakes in flying the pattern. This latest deals with the clover. It seems to me that an alternate way of doing the clover would result in a smoother maneuver and easier for pilot and judges to evaluate the intersection. Perhaps this has been suggested and rejected already. I’m certain it has.

The “leafs” of the clover are numbered; 1=NE corner, 2= SW, 3=NW and 4=SE, in that order. If the clover is instead flown in the sequence 2,3,4,1 here is what I think will improve:

1. The intersection is established immediately after the SW “leaf”. Horizontal and vertical parts of the cross are done in rapid succession, thus decreasing the time for a “memory” fix on the intersection.

2. Entry and exit are both at 45 deg, and in the same circle quadrant (no more diving at the poor judges).

3. It is easier to “squash” the insides of each “leaf” to give a better-defined cross at the intersection.

Disadvantage: You start with an outside down to 5’. But I guess this is no worse than outside round loops.

You are probably right.

However, I'm of the opinion that the pattern wasn't created with ease of flying in mind. In fact, in a conversation with George Aldrich, I asked him why they had the reverse wingover at the beginning of the pattern, when the ship was heavier with fuel and might be tending to run a little richer. Surely it would be easier to fly toward the end of the pattern.

George smiled and said that's why it was where it was.

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"Matter will be damaged in direct proportion to its value." (Murphy's Constant)

Oh no! Not easy. Then everybody could do it. LOL:o

I think Keith Renecle has much better suggestion for this. He reccomend to start from level flight instead of 42 (or 38) to vertical and then follow usual order of loops.

BTW on http://www.rcmodely.sk/Controlline/diskusia.php are some thoughts about clover and there are also dowloadable files including Keith's simulator showing 42 versus 38 problem and also rest of the pattern.

Maybe my old tired eyes are not sufficiently calibrated, but I have a real problem entering at either 38, 42, or 45. I go for "just about right" and I really doubt that judges can tell the difference.

Keith's simulator also shows an even better 4 leaf clover. Start it with a 5 ft corner to vertical flight. Then do four 3/4 loops in the current order, and exit out over the top. The vertical entry establishes a nice centerline to the maneuver for the judges to work from, making it easier to judge. No impossible fussing around with 32 38 45 deg. The only other change needed would be to require the path between the loops to be straight, not "level flight".

Hi All,
Floyd is right about not being able to see the 38, 41.88 or 42 degree in-point from level flight. Keith Trostle's article in Stunt News a while ago, showed that it was calculated by Pete Soule that to have 4 equal-sized loops fitting into the sphere as required by the rules, they have to be approximately 42 degrees in arc. It is close to impossible to see this difference, but I agree totally with Keith in that the rules must be at the very least, technically correct. The problem that I have now, is that we have stopped there and not fixed the problem of flying the horizontal joining lines, and they are dead easy to see from outside the circle. Flying parallel to the ground (straight and level) shows a climbing, or upward curve. The critical points in the rules tell the judges to look for the error of climbing or diving. It also prevents the rule of tangency that require the upper loops to be tangent to the lower loops. The loops cannot be the same size either, if this line is flown through at 42 degrees. Fly this as a straight line (great circle path on a sphere), shows a downward curve from an outside view, but then all the loops can be the same size, and everything fits perfectly. It just looks "different" but is technically correct. Now my question is that if it was deemed necessary to change the AMA and FAI rules to 42 dgrees from 38, so that the rules would be more correct, then why are we not changing the other stuff that is further from being correct, and is also dead easy to see???

Just for fun, try flying the clover with a vertical pull-up directly downwind, and start at the "9-O'clock" point at loop 1. This is so much easier in the wind, and gives an absolute reference to the judges. It also saves airplanes from flying away in strong wind on that first turn. I have seen some of the top fliers in the world crash out in this turn. I know it is a radical change from the "accepted" way, but if the rules are wrong anyway, why can't we do something radical to fix them?

Funnily enough, Charles Mackey showed this problem of tangency in his article on a stunt judging machine, in Model Airplane News in 1963. He also tried to fix the problem via the AMA. It seems like we have not learned much in 40 years! My simulation for the pattern up to the clover, and also the seperate clover sim, are both on Igor's site. They are pretty rough and unfinished, but they illustrate the point clearly. Please read the article entitled "4-Leaf Clover - The Full Monty" as well. There I have stepped through the clover problems in very basic steps. Enjoy!

The published diagrams for the CLOVER show the first "leaf" not intersecting the cross, which all other leaves (leafs?) must intersect. After all, we know that a zero radius corner is impossible; and this would be required if all four elements of the clover should meet at the "imagined" cross point, and tracking a short straght segment- horizontal or vertical.

My suggestion to fly the leaves at 4,2,1,3 would make it easier for flyers and judges to "nail" the cross-point.

It's not a matter or "easier or "harder", it is a matter of being able for judges and pilot to establish a point of reference.

Floyd,

If you will reread Keith's "vertical" entry and if you try it yourself, you will see that his entry to clower DOES intersect the cross at first, and more - also all 4 leafs are identical in shape.

And yes, it gives judges chance to find the proper cross at wanted altitude 45 degrees (not 38, not 42 ... but 45!!!!) - that is what trained judge must be able to do also sleeping at midnight ...

I think this definition is much simpler to judge and define then messing with 42 or 38 degrees or entry by main circle path (down the wind and down the judge eye)

... and my favorable argument - I can repeat such clover several times ... till first lean sound from engine

Mr. Igor. I fly the CLOVER exactly as shown in the AMA and PAMPA diagrams. This entry, not "vertical' but starting at a horizontal 45.

The problem I have is that the first pull-up cannot possibly track the vertical "cross", which should be the intersections of all four of the "leafs" of the clover. Therefore, according to the rule book pattern, the first "leaf" corner does not and cannot track the resulting intersections.

My suggestion would make all "leafs" hit the intersection point.

So, why isn't that a valid change in the pattern?

I do not say that somethingis invalid or bad or what. I just say that Keth's way is cleaner. The reason is, that if you come at 45 deg elevation to the cross point, you WILL cut the upper right leaf. It s because its lowest point is at 38 degrees. His definition also speaks abot foru equivalent leafs with intersection in the middle at 45 degrees.

FWIW, George Aldrich told me in an email that somebody else inserted the exit over the top, not him. He said it took too much power to do this on a windy day. What he did not say, was how he had intended to exit the clover, or if he had intended another entrance point. I can't envision another exit that would be anything other than ugly, but would be willing to enter at the bottom, as into a wingover, do the loops in current order, and exit straight over the top. Maybe I'll try that in a "Judge Warmup" flight, and see what they think. Steve

Try it, it is not bad. In reality I do it very often, but from opposite side when I repeat clover several times.

But Keith got another idea - entry to the first loop by main circle path. It means in level flight, 90 degrees before clover, model enters main circle path at 45 deg - that is line which will end front of pilot at 45 deg elevation - that is actually center of clover and that is also line of horizontal symmetry of upper leafs to lower leafs. That is "doable" in calm, but I had real prolems to get proper pitch angle in wind. So if someone call for difficult figure, this is my favorite #1