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F3C for Dummies

This article was originally published in RC Heli Pilot February/March 2016 issue.
Words and Photos Mike Unger032-2

About 30+ years ago I taught myself how to fly a Carl Goldberg Gentle Lady glider. I would hand launch it, fly it, do it again and again and again. Eventually I moved on, joined a club called the FORKS and got into powered airplanes. A couple “old guys” (I was 14) helped me out and after a few lessons and a few crashes, I was comfortably flying powered models. Now it turned out that our club did pylon racing and after watching it for a season, I tried my hand. I was decent, but more than anything I was hooked on the competition aspect of it. You fly the best you can and at the end of the day there is a winner and a loser. Whoever worked the hardest to perfect his or her craft, won. That life lesson took me into motorcycle racing, kart racing, engineering and two years ago I got back into RC; only this time with helicopters.032-1
This past July, another “old guy”, who I met flying helicopters, noticed the way I fly and suggested I enter the AMA National Aeromodeling Championships (or Nats for short). He said I would learn a lot and might even like it. At the time, work was getting me down, I needed a mini vacation anyway so I said, why not!032-3

The first thing you should understand is what Precision Helicopter Competition is all about. Each competitor is required to do a set “pattern” of flight maneuvers a very specific way. The pilot is scored by a panel of judges on how he or she does the maneuvers. There are multiple classes: Class I or Sportsman, Class II Advanced, Class III Expert and the FAI class F3C. As you move up in class the maneuvers get more and more difficult. Descriptions and diagrams of all maneuvers are available on the AMA website.

All the maneuvers are done on the contest layout which consists of a helipad with a one and three meter diameter target and two flags spaced five meters apart from the center of the pad. All the classes have hover maneuvers and all the hover maneuvers start in the central helipad. The flags mark the end points of the hovering maneuvers. See AMA Figure 5.4.A 033-2

The flight maneuvers are all done with the central helipad being the centerline. That basically means that all of your maneuvers should be centered on the center of the helipad. For example, if you are doing a loop, the center of the loop should be even with the center of the helipad. You can do the flight maneuvers forward of the flight line as deep as you like, just keep in mind that in order for you to be judged, the judges have to be able to see your machine.

After all the competitors in your class complete their turn in front of the judges, the scores are totaled up and ranked. The top score in each class is normalized and given 1,000 pts. After that, each score is ranked accordingly and you get your scores. This gives you a ranking of how you did relative to how everyone else did. You can request your raw scores for each maneuver so you can understand your strong and weak points.

Beginners like me start in Class I or the “Sportsman” class. Looking at the list of maneuvers, you will notice they are pretty simple, consisting of three hover maneuvers, a figure M, an ellipse and an inverted triangle. All of the maneuvers are described in the AMA rules (see 29.1.1 for the Figure M). The ellipse and inverted triangle are very similar and straightforward. Again check AMA rules for details.

The Class I forward flight maneuvers are equally straightforward. Straight flight out followed by a procedure turn with straight flight back. Then a stall turn, a loop, an axial roll and a 45 degree landing approach to a hover and 90 degree turn.

The other forward flight maneuvers are the procedure turn, loop, roll and landing approach, all explained in detail in the AMA rules. (See Loop, Roll, Procedure and Landing Pics next page.)

All of that seems pretty simple right? Honestly, looking at the maneuvers you probably reacted like I did at first and said, “That is too simple for me. I can do so much more”! Well, trust me when I tell you it’s one thing to look at these maneuvers and it’s quite another to do them exactly as described in the rules.

Some things you should keep in mind regarding these maneuvers.

1. The judges judge each maneuver as if there is zero wind. That means if you are dealing with a 15 mph cross wind and the tail rotates out of position by 10 degrees on take off, points are taken off.
2. The judges expect each step of the maneuvers to be exactly as described. If the description says take off and go straight up to 2m and pause, but you take off and hover at 1.5m and don’t actually pause for the full 2 seconds, points are taken off.
3. If you hover three inches to the left of the flags, points are taken off.
4. If you land on the edge of the helipad, points are taken off.
5. If you do the maneuver and you don’t center it with the centerline of the contest layout, points are taken off.
6. If your helicopter gets blasted by a gust of wind and jumps up 1m in altitude and you react as quickly as humanly possible and bring it back into position, points are still taken off.

Get the idea? From the time you take-off to the time you land, everything you do is an opportunity to lose points. Oh, and one more thing, all of your competitors, all of the spectators and everyone else in the pits is watching your mistakes … no pressure there! Keep in mind that nobody gets a perfect 10 and as I mentioned earlier, at the end of the round all of the scores are normalized with the top scoring person getting 1,000 points while second place and so on are scored relative to that score. So when you get your score, you are being judged relative to the best person in your class.

So now you know the very basics about the maneuvers and what is expected. Now you should understand what kind of machine you need to have to be competitive. When I attended this past year’s Nats, I was most interested in understanding what kind of helicopter and what type of equipment was necessary to compete. I arrived on the scene with my Mostro 700 which is a 3D machine, so I instantly assumed I was behind the eight ball in terms of equipment. However, I was so wrong.

The expert pilots that were in attendance explained that it is so much easier today to assemble a good helicopter for precision flying than it was in the past. Most of today’s helicopters are good quality, precisely manufactured and quite powerful. Also, with the improvements in battery technology, the job of finding the right needle setting, the right fuel, the right pipe and so forth are gone as everyone is using electric powered machines. Sorry nitro guys, it’s not that we don’t like nitro, but with everything else that is necessary to tune the machine to do the right thing, eliminating the engine tuning leaves more time to focus on flying. The four Team USA members that were flying at the Nats all had different machines, SAB, Align, Minicopter and Qwest.

Even though these machines were all different, the one thing they had in common was that they were specifically tuned in a way that allows the maneuvers to be done very smoothly and precisely. The scope of the maneuvers is pretty wide when you think about it. Very up close and precise hover maneuvers and some high speed forward flight maneuvers require two different setups. This is made somewhat simple with the help of modern day programmable transmitters and flight controllers.

The hovering setup requires low headspeeds, flat pitch curves, small throws and (depending on your taste) quite a large amount of expo. Low headspeeds help you in two major regards. First, by extending the flight time of your battery which is key to getting all the maneuvers in on one battery. Second, low head speeds make the whole helicopter more docile.

Head speeds in the 1,500 – 1,200 rpm range are typical for your hovering setup. When you are in a hover you need precise control of the pitch curve, but have no need for minus 12 degrees of pitch. So you typically use pitch curves that are very shallow and linear. This is a typical curve (left) for hover maneuvers and is the one I use on the Mostro. Notice that with the reduced head speed (I am using 1,500 rpm), quite a bit of pitch is required for mid stick hover. Also notice that I am still using a bit of negative pitch on the low side to avoid tip-overs when landing in windy conditions.

Dual rates and expo are largely a matter of taste and flying style, but for hovering maneuvers 40 – 50% less than forward flight settings is typical. Exponential control is largely a matter of taste. I prefer about 20-30% expo, but you will need to determine what works best for you. The screen grab on the opposite page details the rates I have arrived at after learning at the Nats.

Forward flight setups are not much different than 3D setups. For a 700 sized machine, head speeds of around 1,900 – 2,000 rpm are typical. Rates and expo are still a matter of taste, but with the large range of maneuvers, you will need to use a large portion of the helicopters capability so full rates are expected.

What about FBL units are best you ask? Well in talking to everyone, the jury is still out on that. I am running a BeastX as are several of the other sportsman guys. The Team USA guys are all running Futaba, but what else would you expect them to run, being sponsored as such? I use the typical 3D kind of setup with one exception. I dial the cyclic gain down a bit.

GROWING THE LOCAL SCENE

• In an effort to have more local contests around the country and to grow the level of participation in the NATS, IRCHA is committing approximately $1,000 toward added incentives toward not only participating in the Nats, but also putting local events on.

• Those contests directors that choose to put on a local event will have their names put into a drawing and prior to the Nats, one will be selected. The winner will have all of their NATS entry fees paid for by IRCHA

• Winners in each class at local events will also have their name put into a drawing. Winner of this drawing will have four days and three nights lodging expenses paid for the duration of the NATS contest.

• If a selected winner is not going to participate in the NATS, the prize will pass to the next winner in that class. Host/ CD must submit AMA form 10 to IRCHA and AMA.

• IRCHA will create a page on ircha.org with winner’s names and results from each contest for all to follow points scoring.

There are already a number of local events listed for the upcoming 2016 season, but be sure to check IRCHA.org for new contests as more become available and listed.

Moral to the story is, to each his or her own when it comes to a controller.

So how did I do at my first Nats? Well to completely honest, I got my butt kicked. My hovering skills were terrible, but I think I learned more in the three days of getting my butt kicked than I learned in the previous year of flying helicopters. The Team USA guys that were there were very helpful. They were willing to not only help me with all my questions, but gave me suggestions on setup and so forth. This is not the type of sport you can just go watch and learn a bunch. Just watching it looks pretty easy, but by doing it and being surrounded by experts that wanted to help, I learned a ton. Now that I have dialed the head speed down, adjusted the rates and expo and adjusted the FBL setting, my hovers are much better. I am working to dial in not only my machine, but also my thumbs and consequently, I have become a much better pilot. Not only have I become better pilot, but I am also learning to deal with wind. This means that when all the guys in the club stay home because there is a 13 mph cross wind, I have the field to myself. Basically, competition or not, when it comes right down to it, practice is what it really takes and lots of it.

So would I say I am hooked? Yep, I met some new friends, learned a ton and I hope by reading this you get interested as well. If you just do the things in this article, you will already be ahead of where I was for my first competition. Doing your first competition at a local event might be a better option than what I did. Check the links below for info on local contests as well. I hope you to see you at the 2016 Nats Aug 1st – 4th.

*** Note all AMA rulebook info and diagrams used with permission from the AMA*** =

CONTACTS

AMA modelaircraft.org
IRCHA ircha.org

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