AMA Class 1 Explained

[ErichF]

I posted this on the RC Helimag forum, and I know some folks here may like this, so here it is:

Well, with the conclusion of the 2007 US Heli Nats, the contest season has pretty much drawn to a close this year. This year was the first for a new set of maneuvers in all three AMA classes of RC heli competition. Having seen, and judged, a number of pilots flying these new schedules this year, I have decided to put together a synopsis of the class 1 maneuvers here.

First, a little homework, students… Go to the AMA site and look up the AMA Competition Regulations. Here is the link directly to the helicopter rules:

http://www.modelaircraft.org/events/...Helicopter.pdf

This is a PDF file, so it can be printed out in a number of formats to suit your needs. In it, you will find all the information you need to know to prepare for a contest. The rules spell out what type of helicopters you can fly, the restrictions they may have, how a contest operated, and how the hovering pad is laid out. The rules also go into how scoring is done. Pay particular attention to paragraph 28, Terms. This paragraph contains a lot of information that I see new pilots missing during their first contests.

The following paragraph, 29, covers the maneuver descriptions. Let’s go through those for Class 1….

The first maneuver is the Tail-In Vertical Rectangle. Here’s the rule:

29.1.1 Tail-in Vertical Rectangle. Model
is positioned tail toward the pilot. Model takes off
from central helipad and rises vertically to eye
level, pauses, maintaining a constant heading,
altitude, and speed, hovers sideways either
direction to the flag, pauses, rises vertically two (2)
meters, pauses, hovers sideways across the central
helipad to the opposite flag, pauses, descends
vertically two (2) meters, pauses, hovers back to the
central helipad, pauses, and descends vertically to
the central helipad.

See the diagrams attached to this Posting for reference. The first part, the take off, needs to be done from the very center of the helipad to avoid a downgrade right away. If the helicopter is off center, have your caller/helper reposition the helicopter prior to spooling up. If you have already spooled up, you are allowed to reposition by hovering it. Just don’t take all day, as the clock is running. Remember, you have 5 minutes to complete your test/trim hovering before the 8 minute round clock starts. The round clock starts when you call the beginning of your first maneuver.

When you are ready to start you first maneuver, your caller will announce the name of the maneuver to the judges, and upon your signal, will announce “Now!” or “Beginning Now!” Have your helicopter spooled up and ready for immediate takeoff just before announcing the beginning of the maneuver. Once announced, lift the helicopter smoothly to skids at eye level hover. It’s OK to go slightly higher, but a severe downgrade is given for low hovering, for safety’s sake. The liftoff for each maneuver needs to be a constant rate, heading, and minimal pitch/roll. Remember, helicopters with a clockwise rotating main rotor will lift off left skid first, due to the side thrust of the tail rotor. If you don’t compensate for this (and any crosswinds) at the beginning of the lift off, the heli will slide over to the left as soon as it comes off the ground. You should make all your lift offs at the same rate and to the same altitude throughout the schedule of hovering maneuvers.

Once at a stable, eye-level hover, count off to yourself, “one thousand one, one thousand two, one thousand three.” Each element of the hovering maneuvers is separated by a minimum two second pause. I use three, as in the heat of the flight, you may count too fast. You get a more severe downgrade for cutting pauses short. After your three count, begin to transition the helicopter sideways in either direction (preferably into the wind) over to the cone or flag on one side. Once settled as best you can over the cone, perform your three count again. As a hint, if you over or under-shoot the cone a small amount, don’t chase it back down. Stop the helicopter and keep it where it’s at for the three count. Then, climb straight up in a hover at least 2 meters above eye level. This is where you can fix your cone position, as you climb. Once you are at the 2m point, stop and three count. Now, start transitioning the heli to the opposite cone or flag. Remember to maintain a constant, tail-in heading perpendicular to the box during all these transitions. Once over the other cone, stop and three count. Descend back down to eye level (remember skids eye level) and again stop for a three count. Then, transition back to the center pad and pause for a three count before descending to the pad.

Throughout the entire maneuver, you need to keep your heading constant (much easier these days with Heading Hold Gyros), and your transit speeds all at the same, constant rate. If you over or under-shoot a flag, just stop and do your count. Chasing flags usually ends up costing you more points for horizontal movement. When you land, make it smooth, with no bounce or tail twitch. Focus on getting the skids inside the 1 meter circle, but a perfect score means the mainshaft is right over the center point. Once on the ground, your caller should announce “complete!” and announce the next maneuver to the judges. Do not spool down the helicopter between maneuvers unless you suspect a problem. Remember, once the round clock starts, you can’t physically touch your helicopter until the round is over. If you need to reposition for the next takeoff, do so BEFORE your caller announces the beginning of the next maneuver.

The second hovering maneuver in Class 1 is the Tail-In Inverted Vertical Triangle. This name is confusing to a lot of people, especially if they have never seen the maneuver before. First of all, it’s not entirely tail in. There are 90° pirouettes over the flags on each side. The term “inverted” in the name refers to the figure of the triangle, NOT the attitude of the helicopter. Here’s what the rule says:

29.1.2 Tail-in Inverted Triangle. Model
takes off from the central helipad and rises
vertically to eye level, pauses, climbs sideways two
(2) meters to the either flag, pauses, turns 90
degrees nose toward the central helipad, pauses,
flies over the central helipad to the opposite flag,
pauses, turns 90 degrees nose out, pauses, descends
two (2) meters sideways back to the central helipad,
pauses, descends vertically to land on central
helipad.

Again, refer to the diagrams below for visualizing the maneuver. As with the first maneuver, signal your caller to announce the beginning of the maneuver. Takeoffs into a stable eye-level hover and do your three count. Next, transition the helicopter sideways and upwards to either end flag and 2 meters above eye level. This angle is close to 30° so start with that. If you make the angle too steep, you end up at a much higher altitude than required, and you may have difficulties controlling the helicopter from such a high perspective. In my experience judging class 1, most pilots actually make the angle too shallow, and often stop over the flag too low. So, visualize the sideways path to a point over the cone and follow that path with the helicopter. A trick I use next works well to keep you over the flag during the 90° pirouette. I “lock” the helicopter onto a distant cloud in the background sky and refer to the cloud for positioning, as opposed to the flag now 4 meters below the helicopter. If you look down at the flag, you’re toast. It should only be in your peripheral vision at best. This also applies to the previous maneuver, the vertical rectangle, as well.

Once you have your helicopter stabilized over the flag for a three count, complete a 90° pirouette towards the opposite flag and do another three count. Then transition the helicopter forward to a point above the opposite flag and pause. Perform another 90° piro in the opposite direction (back to tail in) and pause. Lastly, transition sideways and downwards back over the center pad and pause. Complete your landing and make sure your caller announces “complete!”

The last hovering maneuver in Class 1 is the Spike with 90° and 180° pirouettes, and can be quite intimidating for new helicopter pilots. While simple in form, the top 180° piro has caused many new pilots to lose focus. Here’s the rule:

29.1.3 Spike with 90 and 180 Degree
Pirouettes. Model Takes off from central helipad
and rises vertically to eye level, pauses, turns 90
degrees either direction, pauses, climbs two (2)
meters, pauses, turns 180 degrees tail in, pauses,
descends two (2) meters, pauses, turns 90 degree
nose out, pauses, and descends vertically to the
central helipad.

Prepare for the maneuver as before – centered and on heading. Announce beginning and lift off to eye level. After your pause, piro the helicopter 90° in either direction towards one of the flags. Another tip here is to piro the nose downwind, with the tail into the wind. The reason for this is that helicopters would rather climb with a tailwind than to descend with one. Turning the tail into the wind here places the nose into the wind for the descending portion of the maneuver. Now, after your three count, raise the helicopter 2 meters vertically and pause. Then, perform a 180° pirouette, nose-out, so that the heli is pointed at the other flag and pause. Then, descend vertically 2 meters and pause. Pirouette back to tail in and pause. Lastly, descend to and land on the center pad. Remember to signal your caller to announce complete, if he doesn’t already.

That’s it for the hovering portion of Class 1. I’m going to take a break and discuss the forward flight, or “upstairs” maneuvers in a later post. I have, however, created and posted diagrams of all eight maneuvers of Class 1 in this post. Go ahead, print them out, and attach them to your copy of the AMA rules PDF. Feel free to pass them around to your flying buds and see who can manage their helicopter the best. It could turn into a fun exercise for everyone at your next gathering. Until next time, practice often, and HAVE FUN!

[GM1]

Erich,
You're hired. Nice diagrams.
Gordie

[ErichF]

Thanks, the hard one was the procedure turn.

Hope they prove useful. I will work on Class 2 and 3 eventually.

[Kinger]

Very nice job Erich. Certainly helps things when you understand what you are supposed to be doing.

[Georg Matthews]

Very nice Erich, this kind of help and attention to details is exactly what is needed.
Thanks
George

[ErichF]

I forgot to mention the Class 1 videos I took while at the Nats. Baron Johnson with his dad Fred calling:

Hovering:

AMA Class I Hovering Manuevers (4 min 37 sec)

Upstairs:

AMA Class I High Manuevers (2 min 49 sec)

These should help clarifying anything else.

[Rocket Man]

Erich,

You mentioned in the first maneuver that "Remember, once the round clock starts, you can’t physically touch your helicopter until the round is over." IIRC, you are allowed to change batteries in an electric powered heli between the hovering maneuvers and the flight maneuvers. I think the rule gives you two minutes to do this, if I understand everything correctly. Do you know if this is correct?

The rules give you eight minutes to do the full Class 1 schedule, but how much time do people usually take in reality?

2007 was a difficult year for family travel. I am already planning for Tampa next year.

Take care,

Ron

[Torq]

Are there supposed to be diagrams in the post itself?
If so, they may have been lost in the Forum upgrade.

Would love to see them though!

[ErichF]

Hey guys,

Sorry I didn't respond sooner, apparently my subscription to the thread got dumped in the change over, and so did the diagrams. I have uploaded them to the thread again. There is now a 5 pic limit to each post, so they are spread across the original post and this one.

Ron,

You are correct. In the event you are flying electric, you are allowed to change your pack before you go upstairs. I think for FAI they are eliminating that, however. I need to ask Gordie or Cliff if the same will apply for the AMA classes.

The 8 minutes is easy to pull off in Class 1 and 2. Class 3, at the Nats, was running about 7:30ish. I did class 2 in 7 minutes on average, and that's with 3 second pauses. Class 2 flows a lot better than Class 1, though. Class 1 has a couple downwind manuevers back to back requiring at least one free pass.

This reminds me, I need to finish the schedule!

More to come,

[ErichF]

The AMA Class 1 flying maneuvers (or, "upstairs" maneuvers) are simple, forward flight items that require minimal effort to accomplish, but we aren't just out to get through them. We want to perfect them.

The first maneuver is the Procedure Turn, here's the rulebook version. Refer to the diagrams posted earlier:

29.1.4 Straight Flight Out, Procedure
Turn, Straight Flight Back. Maintaining constant
altitude, the model flies straight and level past the
midline, executes a 90 degree turn away from the
judges and then an immediate 270 degree turn in
the opposite direction, and flies straight in the
opposite direction down the original line of flight.

This first maneuver can be a little confusing to new pilots, as the visualization is difficult. Essentially, the maneuver is just a turn around with the helicopter flying just past center, executing a 90 degree turn away from the line, followed by an immediate 270 degree turn back towards and parallel to the line and past center again. You should enter the maneuver going downwind. The execution of the maneuver should be done so that the model is rolled into the turns, and rudder is coordinated with aileron throughout the turns. The model should not be kept flat and simply ruddered around the turns. A good presentation of the maneuver should consist of turns using at least 45 degrees of bank angle. Remember, you have to fly at least 10 meters past center before you execute the first turn, and your caller or you announce complete as you pass center, but not before. You can announce the beginning of the maneuver as you pass center, but want to avoid calling it after center. The shape of the procedure turn should be symmetrical, forming a perfect teardrop.

The next maneuver is the Stall Turn. Every pilot breaking into forward flight has played with this one at some point. It’s a classic, elegant way to reverse direction. The rule says:

29.1.5 Stall Turn. Model flies straight
and level past the centerline for ten (10) meters
minimum, then climbs vertically with a smoothly
rounded curve of 90 degrees. When the vertical
climb stops, the model rotates 180 degrees in yaw
so that the nose points straight downward. While
diving, the model follows the same path as the
beginning of the maneuver. The start and finish of
the pull up should be on the midline and the vertical
line is offset in the direction of flight.

Again, you fly the model past center 10 meters before starting the maneuver. This maneuver is started downwind, so can be done after the Procedure Turn without a free pass, since you finished that maneuver into the wind. Perform a turn-around of your choice and establish the model on a downwind, level line parallel to the flightline. Call the start of the maneuver as the model passes center, and continue at least 10 meters. At this point, begin a SMOOTH ¼ loop to a vertical line. As the helicopter transitions to a vertical attitude, reduce collective to zero pitch, such that the helicopter coasts up an imaginary vertical path. You may have to adjust collective pitch slightly to compensate for winds. The idea is to draw a perfect, vertical line with the helicopter. Also, enter the maneuver at full speed, so that you have enough momentum to present a nice, long vertical line. This means you may have to take the helicopter out farther after the first maneuver to give you room to accelerate into the stall turn.

Now, don’t fall asleep as the model ascends this long, beautiful path into the sky. Just at the point the helicopter looses momentum and stops, briskly, but smoothly, pirouette the helicopter with rudder around to a nose down attitude. Be careful not to over or under rotate the nose. You lose a point for each 10 degrees off heading. Once pointed downward, maintain collective and cyclic to neutral, +/- wind corrections until the model has descended at least one airframe length. Ideally, the perfect stall turn means you pull out at the same altitude you pulled into the maneuver. Keep that in mind when you setup to enter the maneuver to begin with, knowing that you have to wait until you get to that altitude before pulling level. A low entry means a low pull-out…maybe something you aren’t comfortable with. Once back to straight and level flight, continue past center, flying upwind, and call complete. Fly well out to the upwind side of the field and perform a turn around of your choice (typically an un-judged stall turn).

The following maneuver is simple and elegant in appearance, as much as it is surprisingly difficult to perform well. This is the Cobra Vee. Rulebook says:

29.1.6 Cobra Vee. Model flies straight
and level for ten (10) meters and climbs at a
smoothly rounded curve for 45 degrees, flies
straight for ten (10) meters minimum, executes a
sharp 90 degree pushover to descend at 45 degrees,
descends in a straight line for ten (10) meters
minimum, recovers to level flight in a smoothly
rounded curve that matches the initial pull, flies
straight and level for ten (10) meters at the original
altitude. Maneuver should be centered on the
midline.

Again, this maneuver needs lots of speed to pull off a nice presentation of the shape. Basically, it’s just a 45 degree upline followed by a moderate pushover into a 45 degree downline. Get as much forward speed as you can get after your turn-around, and stabilize the model for the maneuver. You should be flying this one downwind, as well. Here, judgment of the model’s speed and trajectory begins to become important. You have to judge when to pull up into the 45 degree line, so that the model looses most of its forward speed right at center. The trick is to reduce collective enough so that the model coasts up this 45 degree line like a roller coaster. If you reduce too much, the model just noses up and stops. Not enough, and the model zooms up into a steep climb and stops well away from center. Make sure to call the beginning at least 10m before you reach your pull up point.

Now, as the model approaches the top of the maneuver, make sure your rotor disk is level and prepare for the ¼ push over. As the model passes center, smoothly rotate the model forward to a 45 degree downline, keeping heading and disk level. Apply a bit of collective to allow the model to accelerate and “slide” down the back side of the maneuver. Don’t force it down, let it naturally accelerate. Since the maneuver is to be flown symmetrically, you have to judge the pull-up point to be the same distance from center as you pulled up at the beginning. Also, the altitude needs to be the same. Keeping this in mind, when you reach this point, smoothly pull the nose up to level and fly straight out. Continue level for at least 10m then call complete. Again, fly out and perform a turnaround.

The next maneuver is equally under estimated, the Axial Roll:

29.1.7 1 Axial Roll. Model flies straight
and level for ten (10) meters, executes one axial roll
and flies straight and level for ten (10) meters

This maneuver is best performed downwind, also. So, following the Cobra Vee, you need to take a free pass upwind and turn around for a down wind pass. Again, judgment is key to centering the maneuver correctly. You have to call the start of the maneuver at least 10m before you execute, and the model should be inverted as it passes center. So, enter the maneuver with moderate speed. Don’t rush this one, as rolls can be really screwed up if you bury the collective trying to get lots of speed. As you enter the maneuver, make sure your tail is straight behind the model. Use the smoke trail as a guide to align the tail. When ready, begin the roll with moderate left or right cyclic, and phase the collective to match the roll position of the model. You should have nearly zero pitch on knife-edge, and slightly negative pitch inverted. A common mistake is to bury the negative pitch while inverted in an attempt to keep up speed. In actuality, the result is usually a reduction in forward speed as the added drag of so much negative pitch + cyclic slows the model down. Time the roll so that you pass center inverted and come to upright the same distance from center that you started. Obviously, you should also be at the same altitude throughout the maneuver. Some pilots chose to roll quickly, so as to avoid needing corrections, while others (myself included) prefer to roll slower so that corrections can be made. Whatever the case, just be sure the maneuver is symmetrical. Fly 10m after rolling upright and call complete. Continue downwind of the field and turn around.

The final maneuver is relatively simple, but can be easily fowled up if you don’t use good speed judgment. This is the Landing Approach to Eye Level Hover:

29.8.1 Landing Approach to Eye
Level Hover. Beginning at a minimum altitude of
ten (10) meters, the model will descend in a straight
line parallel to the flight line, maintaining a
constant rate of descent to an eye level hover over
the three (3) meter central helipad, turns 90 degrees
to tail in, and hovers for two (2) seconds.

After performing the turn around following the roll, you should be headed into the wind. Before you come too close to the pad, begin slowing the helicopter down to a fast walking pace. At a point 10m out and 10m up, call the beginning of the maneuver. Keeping your speed constant (about walking speed), descend at a constant angle that ends at an eye level hover position over the pad. It does not necessarily have to be 45 degrees, just as long as the angle is constant and flown at a constant speed. Once over the central pad, pause for a three count, and pirouette the model 90 degrees to nose-out. After a three count, call the maneuver complete, and the flight complete. Then, land at your discretion.

See you on the line,

Erich

[Niko]

Outstanding job Erich.

Thanks for putting all this together. Its just the information I was looking for.

[ErichF]

Thanks! Glad you could use the info.

[DeadTom]

I have been flying fixed wing RC for many years and only 2 1/2 years with helicopters. I am self taught and I have 6 micro/mini heli at this point. I have been interested in trying this style of flying to improve my skills. Is there a heli size that is required to compete at the AMA class 1 competitions? And where do these competitions take place along the west coast? I am in the north western part of Nevada, Sacramento it the largest California city to me.
Also, thanks for your time.

Tom

[ErichF]

Hey Tom,

Glad to see your interest! The bad news is that there currently are no contests west of the Mississippi. So, the best bet is to get some local flyers together that share your interest and hold some casual gatherings. You could also get a CD to do the paperwork and hold an official AMA/FAI contest like here in the East.

You can fly any current design helicopter in competition, to include electrics under 42V. Obviously, some will be better than others, but for class I, you can get away with flying just about anything. Larger nitro powered models do present better, and generally have better adjustability to suit your flying needs.

Good luck with your practice,

[DeadTom]

Thanks for the quick reply Erich, I really don't have anyone around here that flys helicopters. Trying to get to my older brother interested in flying with me.
I will try to practice with my Dragonus 450 sized heli, I have been looking at a 30 or 50 sized ship next. Gotta sell some of the micros first.
I ws thinking of becoming a CD and trying a small indoor electric fun fly and see what transpires. Wish me luck.

Tom

[rsalazar]

Erich, thank very much for these information. It is great

[DeadTom]

Well to become a CD for the AMA you 3 years "continuous" membership, my membership has been on and off over the years. I guess mostly off until about 8 months ago when I decided I would like to fly at the local fields. The fields are AMA sanctioned but most people are flying airplanes. So maybe in a couple of years I will be ready to try a AMA class 1 competition west of the Mississippi.

[jaallen]

Thank you so very much Erich. Your hard work and the videos posted will help me alot.

I look forward to your work on Class 2 and 3.

Thank You brother, see ya out there too,

J.A

[tz250w]

I just wanted to add my thanks too. Even though I'm living outside the US, having something to study (in English) about comp flying is great.

Japanese are big on F3C, more so than the 3D stuff so I'm judged every time I hover...

I'm not planning on entering competition anytime soon, if ever but I am interested in improving my flying and "honing" my skills. This looks like the way to do it!

[Forced_Induction]

Thats interesting. its the same routine flown in fixed wing pattern contests. except for the hovering maneuvers.