By coordinating rudder deflection with the aileron (rudder moving in the same direction), you prevent the nose from skidding to the left. Adverse yaw is thus prevented; banks and corrections, even rolls, will be smooth and axial, and you will feel more connected to the plane.

When a loop-or any maneuver related to one-is performed in a crosswind, the airplane will drift sideways with the wind during the slower portion of the loop. This drift will generally happen as the plane rounds over the top of the loop. Consequently, a loop that was entered on a parallel flight path with the runway will exit downwind-no longer tracking parallel. If you don’t use the rudder, you will have to do a number of corrections afterwards to reestablish the preferred parallel track taken at the start of the loop.

To correct cross-wing drift, apply rudder in the opposite direction the wind is blowing. For example, if the crosswind will blow the plane to the left, a right-rudder wind correction would prevent it. Ailerons are for keeping the wings level before and during a loop. Don’t try to correct wind drift by creating a new [wing] deviation using aileron; sideways wind drift is a function of yaw, not roll.

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FIRST THINGS FIRST
When performing a graceful maneuver like the loop, focus your attention on geometry and smoothness. When executing the “loop” portion of this aerobatic maneuver, you want a low-rate setting that has about 12 degrees of elevator deflection, 30 degrees of rudder deflection, 25 degrees or more of aileron deflection and exponential on all surfaces. As a starting place, I recommend you use about 20% of expo and increase it until you are comfortable with how the airplane responds. Keep in mind that adding expo will soften the feel of how your servo reacts around neutral.

Let’s now discuss the snap roll. The snap roll rotation should happen relatively fast, and if you find that your model “barrel rolls” around in rotation, you do not have enough control surface deflection and may need different rates on your radio. Most models will snap with about 15 degrees of elevator, 35 degrees of rudder and 35 degrees of aileron throw, but again, values differ from model to model. This serves as an overview, and fine-tuning your model will be up to you. As I mentioned earlier, use exponential and start with a value of about 35% on all control surfaces and then make any necessary adjustments.

When I perform a maneuver like the avalanche, I keep my model on my low-rate settings for the “loop” portion of the maneuver. Then, when I want to initiate the snap roll, I switch to my high-rate setting. I perform the snap and flip immediately back to my low-rate setting for the rest of the figure. To simplify matters, I use flight modes, which means that all rates can be found on one switch!

AVALANCHE OVERVIEW

Until you are familiar with this maneuver, I recommend you climb to an altitude of about 150 feet. Keep in mind, though, that this altitude will vary depending on the size of your model; this starting point is great for an electric model with a wingspan of about 50 inches.

Once your altitude is established and your airplane is traveling parallel to the runway, increase the throttle and begin a gradual loop right when the model passes the pilot (for future reference, the pilot’s position is called the “center”). Keeping the same radius, it’s critical to perform a snap roll at the top of the loop. If the loop began immediately after the model passed the pilot, the snap should be performed as the model is inverted over the top of the loop and at center. Once the snap roll is performed, the model continues the second half of the loop and exits at the same altitude at which the maneuver began.

Now, let’s simplify the control inputs needed and divide this maneuver into four steps:

1 Begin by climbing to a safe altitude and orienting your model so it’s traveling parallel to the runway. The throttle will vary depending on your model’s power-to-weight ratio and the size of your loop. If your model has a fairly equal power-to-weight ratio, you’ll need to use maximum power, especially if you want to perform a larger loop. Increase the throttle to about 90% for your first attempt, and wait until the model approaches center.

2 If you’re using dual rates, make sure you’re on your low-rate setting. As the model is at center, gently pull back on the elevator control surface to begin the loop. Geometry is the key, and it’s critical to perform a perfect circle. With that being said, you may need to increase your throttle to keep the speed of the model constant. Also, you may need to make various rudder corrections to keep the model at the same distance from you (nine out of 10 times, you’ll need to apply right rudder due to motor torque). Keep the same radius constant throughout, and when the model is almost halfway through the loop, it should almost be at center, but inverted. This is a key moment to flip to your high-rate settings, or what I call my “snap rate condition.”

3 Initiate the positive snap roll by applying full left rudder, left aileron and up-elevator (if performing the snap to the left; otherwise, right rudder and right aileron with up-elevator). After one complete rotation is performed, neutralize inputs and immediately flip back to your low-rate setting and decrease the throttle to about 10% power.

4 Complete the second half of the loop. When the model is 75% done with the loop, it may be necessary to lower the throttle to idle. However, keep in mind that you may need to increase the power again as you are approaching center (the same point at which the maneuver began).

Now that you have learned how to properly execute the avalanche, let’s discuss a few key tips. If you are flying in an extreme headwind, you may need to gradually pull the model up to initiate the loop and then pull back harder once it has completed the first quadrant, as the wind may push you toward center faster than anticipated. After the snap is performed, you’ll need to pull a little harder on the elevator until you are about 80% done with the loop. You then ease off elevator to complete the maneuver as the model is directly in front of you. Whether you are flying in a head-wind, which we just described, tailwind, or crosswind, it is critical for this maneuver to be centered and performed directly in front of you. Make all necessary adjustments so the model always remains at the same depth from you and that it reaches the cardinal points.

Illustration by FX Models

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If you want to achieve a good snap roll, practice is mandatory. The snap roll is an auto-rotation maneuver in a stalled condition. During a snap, one wing is stalled while the other is accelerated about the roll axis. This creates a sudden roll-rate acceleration that you can’t obtain by simply inputting aileron. To achieve this condition in a model, several inputs must be given, including elevator, rudder and aileron. Pilots of full-scale planes will scoff at the idea of adding aileron because it is not required when they deal with wing loading figures in the range of 35 pounds per square foot. Our models, however, typically carry a wing loading of from 20 to 40 ounces per square foot, so their flight dynamics are different from those of full-scale planes.

FLYING THE MANEUVER
The simplest snap is known as the “inside snap.” This maneuver is performed from the upright position and is induced by adding elevator, rudder and aileron. Before you try this maneuver, be prepared for your plane to rotate at least twice as fast as it does during a typical aileron roll. You probably won’t even see your plane perform the maneuver because it happens so quickly. Instead, you will barely have started your control inputs when you’ll immediately have to think about recovery.

Make sure that you have enough altitude to allow mistakes! Now take the airplane to a comfortable altitude at least 100 yards in front of you, parallel to the runway. Enter the aerobatic zone and fly to the center of the box at mid throttle (not full throttle). From level flight, perform an inside left snap by simultaneously applying up-elevator, left rudder and left aileron for 1 to 2 seconds.

Recover from the maneuver by neutralizing the sticks and immediately adding right rudder to correct your loss of heading. Maintain the mid-throttle setting throughout the maneuver.

FINESSING THE MANEUVER
There are several places where a little finesse will go a long way. Most pilots bury their sticks in the corners of their transmitters to snap their planes. This typically creates a stall in which too much energy is depleted, and recovery is very difficult. This condition is known as “snapping too deep.” Your goal is to fly through the maneuver with enough inertia to allow the airflow to re-attach to the stalled wing on demand. To accomplish this, you will need to decrease the elevator and/or rudder input until your plane just barely snaps. The only way to find this point is to practice it. When you find the perfect combination of elevator, rudder and aileron, practice it over and over until you can easily duplicate it.

The post Nailing the Snap Roll appeared first on Model Airplane News.

To properly execute this maneuver, you need to apply proper control inputs at precisely the correct time. To consistently execute the maneuver, your aircraft will need to be properly tuned and set up. It must have the proper center of ...

The post The Lomcevak: The Classic RC Manuver appeared first on Model Airplane News.

STEPS TO SUCCESS
Step 1. Start the maneuver by flying at full power, straight and level, with the wind or downwind. Apply up-elevator as if you’re going to do a loop.

Step 2. Continue the loop until the plane is inverted and heading downward at a 45·degree angle. As the plane goes over the top of the loop, release elevator and reduce power; if you don’t, it will pull the plane off to one side during the roll. Be sure to keep the wings level during the loop.

Step 3. Apply aileron and roll upright. After doing the roll, let the plane continue downward until it is at the same altitude as when you started the maneuver.

Step 4. Add throttle and up-elevator to start the second half of the maneuver and perform another loop and 1/2, roll and finish the maneuver in the same way as you did the first half.

Step 5. When you exit, you should be flying in the same direction and at the same altitude as when you started.

PRO TIPS
• As you become more proficient, make the loops larger and pause for a second before the roll. Try to place each roll at the same altitude so the maneuver looks symmetrical .

• Try a reverse Cuban-S and do the roll first. Start at a safe altitude, and apply up-elevator to make the plane climb at a 45-degree angle. Roll to inverted, decrease throttle to idle and pull up-elevator until the plane completes the first part of the loop. Recover, then increase power and do the other half of the maneuver in the same way you did the first.

The post Mastering the Cuban-8 appeared first on Model Airplane News.

Here’s how I did it with my Zenoah G-20 powered 1/4-scale J-3 Piper Cub from Hangar 9.

 

 

 

 

 

   

Step 9: The area at the end of the brass tube will be the baffle section and will need to have several holes drilled into it! Drill several holes in the end and then sand smooth. Slip the baffle tube into the muffler until it bottoms out and is flush with the exhaust pipe.

The post Home-Made Smoke Muffler appeared first on Model Airplane News.

The reason I am explaining this is simple. Too many times, I see pilots trying different and extreme maneuvers and oftentimes the airplane is in control, but not the pilot. To become really successful we must stay in control and this requires lots of practice.

Maneuver breakdown

For this maneuver, the pilot enters from inverted flight and pushes to establish a 45-degree climb then he performs 1½ negative snaps. After the snap, another line segment (equal to the first line) is then executed. Once the maneuver is complete, the pilot must pull 135-degrees to exit in inverted straight and level flight.

This is a good maneuver to help teach you how to perform cleanly while being aware of any corrections being needed for maximum points. As with most maneuvers, with lots of practice, you learn to correct subconsciously which is the goal for anyone wanting to be a serious aerobatic and or 3D pilot.

Enter Inverted straight and level

1 Apply about 80% power and push to an inverted 45-degree upline.

2 After a straight line segment of about 75 feet, switch rates and perform 1 1/2 negative snap roll.

3 After the snap, switch rates to low, reduce throttle and maintain straight, upright line segment (75 feet).

4Pull up-elevator to perform 135 degree radius and establish inverted flight.

Exit Inverted straight and level

Maneuver overview
Climb to a safe altitude, roll to inverted, line up for the maneuver flying parallel to the runway and apply about 80% throttle. Push gently and establish a 45-degree inverted climb. After the radius and the climb is established, note the flight distance before the 1½ negative snap is started. You will have to fly a similarly long inverted flight segment after the snap roll. I usually count to myself and for this maneuver, a two-second segment seems about right. Flip to your Snap Mode and, all at the same time, apply down-elevator and opposite rudder and aileron. After the snap segment is complete, neutralize your inputs to establish a 45-degree upright climb. If you fly at a constant speed, then count to yourself again for two seconds. Now, pull 135 degrees to exit the top of the maneuver straight, level and inverted.

By the numbers

STEP 1: Enter the maneuver inverted and parallel to the runway. When ready, make sure that you apply at least 80% throttle and push down-elevator, ever so slightly, to perform a smooth radius and establish the 45-degree inverted climb.

STEP 2: After a line segment of about two seconds (about 75 feet in length,) flip to “mid-rate” and perform a 1½ negative snap roll. The key to performing the snap roll properly is timing and setup. If your airplane becomes too “deep” in pitch and is difficult to stop constantly on a 45-degree climb, you may need to dial the elevator rates down a touch. Also, for this segment of the maneuver, you may need to either increase or decrease the throttle to maintain constant flight speed.

STEP 3: After the snap roll, flip back to the “low-rate” setting, and perform a line segment that is equal in length to the first. Balance the throttle, as needed, so that the airplane maintains a constant flight speed and apply rudder input, if needed, to keep a constant heading. In a crosswind, you may notice the nose of the aircraft drifting into the wind. You will have to use just enough rudder to correct.

STEP 4: Exit at the top by pulling 135 degrees to establish inverted level flight. It will be necessary to hold a touch of down elevator to keep the altitude constant. You model’s CG location with affect how much down elevator is needed. Nose-heavy airplanes require more elevator input.

Like I mentioned earlier, it is important to take small steps to accomplish your goals and perfect a new maneuver.

BY JOHN GLEZELLIS; ILLUSTRATION BY FX MODELS

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Let’s begin by noting that using rudder in a rolling circle is a high-end refinement used mostly to keep the turn radius perfectly round and perfectly level. But because you need to be able to fly a rolling turn before you can refine it, we’ll initially leave rudder out so you can concentrate on the primary controls of aileron and elevator, and thus more quickly achieve some success to build upon.

The best way to learn a rolling circle is to first learn one 90-degree segment with the airplane rolling to the outside of the turn (e.g., rolling right while turning left). Most people find that rolling to the outside of the turn is easier because, as I’ll explain, each rolling turn ends with you comfortably pulling elevator instead of pushing elevator. You’ll initially want to perform this maneuver so that the airplane will be turning away from you. For example, when you enter the rolling turn from left to right and initiate a slow right roll, your first elevator input pushes the nose of the airplane into a left turn and away from you. It is also wise to enter your first attempts from a slight climb, so that you can concentrate on using the elevator to effect the rolling turn without worrying about controlling altitude.

LET’S GET STARTED

ROLLING CIRCLE
Begin by maintaining a small (right) aileron input to achieve a slow roll rate and give you time to react. As the wing approaches knife-edge-with the bottom of the plane facing the inside of the turn-smoothly push enough forward elevator to induce a turn, and then smoothly take out the push. As the wing approaches knife-edge-with the top of the plane facing the inside of the turn-pull enough elevator to continue the turn. Neutralize the controls when the wings return to level. Don’t be too concerned initially with turning exactly 90 degrees. The early goals are to be able to maintain a small aileron input and to push and pull at the correct times.

It’s best to pace your push and pull with the time it normally takes to say or think “push” and “pull.” By smoothly inputting the elevator at this pace and starting as the wing approaches knife-edge, the elevator will peak at knife-edge, where it is most effective at causing the turn, and be returned to neutral well before the wing approaches level. Note that almost all errors at this point are the result of increasing the aileron and changing the roll rate, leading to an inability to manage the elevator properly. In this event, you’ll need to pay more attention to your input and maintain less aileron while pushing and pulling. Keep in mind that the pushes and pulls are typically much larger control inputs than the aileron input.

REFINING THE ROLLING 90

“OUTSIDE” ROLLING 90^o LEFT TURN

Flying left to right, climb slightly before initiating a slow right roll, then push the airplane into a left turn away from you as the wings approach knife-edge.

The periods when the wings are banked 45 degrees and steeper is when the elevator is most effective at turning the airplane. Therefore, those are the keys times to smoothly push and pull during the roll.

AS YOUR ABILITIES INCREASE, YOU SHOULD AIM TO COMPLETE ONE ROLL IN A 90-DEGREE TURN

The eventual objective is to complete the roll at the 90-degree point of the turn. If the roll is projected to finish before reaching 90 degrees of turn, slow everything down. If the roll is projected to finish past (over-shoot) the 90-degree point, speed everything up. Rolling too fast will result in completing the roll before achieving 90 degrees of turn.

As your abilities increase, you should aim to complete one roll in a 90-degree turn. For example, if you start the maneuver parallel to the runway, aim to complete the roll perpendicular to the runway. If, for example, you find that you’re completing the roll before reaching 90 degrees of turn, slow down the roll rate to lengthen the time that the plane is on its side. In doing so, you will also lengthen the duration of the push and pull and effect more turn. In other words, when you slow the roll rate, the pace of the elevator inputs also has to be slowed down to correspond to the longer periods when the plane is on its side.

ROLLING 180-DEGREE TURN

“OUTSIDE” TWO-ROLL ROLLING 180^o TURN

If a climb is observed, decrease the size and pace of all the inputs. If a descent is observed, increase the size of the elevator pushes and pulls.

The next phase is to perform a two-roll, rolling 180-degree turn. A rolling 180 is flown as one rolling 90 to the cardinal point perpendicular to the runway and, without hesitation, continuing into another rolling 90 to the next cardinal point parallel to the runway. There is little additional challenge to performing a rolling 180 compared to the 90, although altitude changes become more apparent during multiple-roll rolling turns.

As a rule, when the airplane loses altitude during a rolling turn, the pushes and pulls are too small and/or too brief. Thus, if the plane starts losing altitude, increase the size of your pushes and pulls, which naturally extends the length of time that they are held in and helps to keep the rolling turn level. If your plane starts to climb, lay off a bit on the size of the pushes and pulls. But remember, if you reduce the size of your elevator inputs, the turn will also widen, so you will likely have to reduce the roll rate to buy more time to reach the cardinal points.

OUTSIDE ROLLING 360 CIRCLE

“OUTSIDE” FOUR-ROLL ROLLING 180^o TURN

Simplify the process of performing a four-roll rolling circle by thinking of it as a rolling 90, which is then repeated again, and again, and again. I.e., rather than thinking about t he entire maneuver, confine your thoughts to thinking about rolling to the next 90 degree cardinal point.

A full rolling circle is comprised of four consecutive, rolling, 90-degree turns. The most common mistake at this point is getting caught up in a rhythm of pushing and pulling that results in inputting elevator before you need to, which would force the airplane into a descent. Remember that any change in the roll rate will change the elevator timing, so always watch the wing to trigger your elevator inputs and avoid falling into a rhythm of blindly inputting the elevator back and forth.

PERFECTING WITH RUDDER

LEFT TO RIGHT ENTRY

Initiate a right roll and smoothly apply left rudder into the turn. Introducing rudder into your rolling turn will help to keep the turn radius constant when the wings are level and ensure that the nose does not drop during knife-edge. The rudder is not nearly as influential as the elevator, so you don’t need to be too concerned with how much rudder you apply and can instead concentrate on getting the timing of the rudder inputs correct.

When you can perform a reasonably good “outside” rolling turn, you can use rudder to perfect the maneuver. Start by simultaneously initiating a gentle right roll and smoothly applying left rudder into the turn. As the wing passes through knife-edge, start smoothly switching to right rudder. And when the wings reach knife-edge again, start smoothly switching back to left rudder. Altogether, the input sequence upon initiating right aileron is, “Left rudder, push elevator, right rudder, pull elevator.” Repeat this sequence three more times, and you will have performed a precision rolling circle. Congratulations!

•  Stiffer control stick tension.
•  A good grip on the transmitter.
•  Supporting your thumb with your index finger.
  

TEXT & ILLUSTRATIONS BY DAVID SCOTT, 1st US RC FLIGHT SCHOOL 

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Brief Bumps are Key!
Your rudder and aileron corrections must be brief. If you’ve watched car racing on TV, you may have noticed the in-car camera shots of a driver bumping or nudging the steering wheel. That’s because race cars are typically driven on the edge of control, and if the driver over-controls just once, he can send the car spinning out of control. To avoid spinning out, race car drivers make several smaller (bump) corrections rather than one larger correction. Similarly, an airplane teeters on the edge of control during most 3D maneuvers, and thus your rudder and aileron corrections must be kept brief to avoid aggravating the wing-rocking phenomena.

Elevator-Flap Mix An effective technique used to reduce wing rock is to activate the elevator/flap mix so both ailerons raise up approximately 20-30% when you hold in full up-elevator .While you’re at it, you might as well program both ailerons to lower 20-30% with down-elevator to complement future inverted 3D maneuvers.

Elevator Summary
Point the airplane into the wind, cut the power, and smoothly pull full up-elevator. When the plane stalls, add a few clicks of throttle to keep the fuselage level and hold in some right rudder to correct for propwash and P-factor. Correct deviations with brief bumps of rudder and use coordinated aileron and rudder inputs to correct larger wing deviations. Keep your fingers moving, and if the wings start to rock uncontrollably, exit the maneuver by relaxing the elevator and adding power.

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The classic Lomcevak is a tumbling maneuver where the aircraft’s tail rotates in front of the engine throughout the maneuver. The maneuver has Eastern European roots and the word “lomcevak” translates to headache.

To properly execute this maneuver, you need to apply proper control inputs at precisely the correct time. To consistently execute the maneuver, your aircraft will need to be properly tuned and set up.  It must have the proper center of gravity, adequate control surface deflections, and enough power to tumble end over end.

To perform the Lomcevak properly, you’ll need a minimum of 30 degrees of control surface deflection for all control surfaces and an exponential setting of about 50%. I would also recommend the use of dual and/or triple control rates. If you’re having difficulty performing the Lomcevak (only entering a tumble), try increasing elevator input and move the center of gravity back a little more.

Overview

In its most basic form begin the maneuver from upright level flight going into the wind. As the aircraft approaches the midpoint, establish a 45-degree up-line with about 80% power. The throttle setting will differ depending on the model’s weight and power. Adjust your throttle setting accordingly to suit your aircraft.

Next roll the model 90 degrees into knife-edge and then apply full down-elevator combined with aileron and rudder inputs in the same direction. With proper throttle management, the airplane will tumble end over end. After the tail rotates forward, the model will lose most, if not all, of its momentum. Maintain a moderately high throttle setting and time your control inputs so the airplane once again establishes upright level flight on the original heading. The Lomcevak is performed traveling over an arced path and exits in upright level flight.

As with all new maneuvers, practice at a fairly high altitude. If the aircraft is too close to you, it may become difficult to apply certain corrective inputs as the model nears end of the tumble. If during the maneuver you become disoriented, abort the attempt and pull into upright level flight.

Illustration by FX Models

By the Numbers

Step 1. At a fairly high altitude flying into the wind, align the aircraft with the runway and enter the maneuver in upright level flight. Switch to high rates, then as the model is about to pass directly in front of you, increase throttle to 80% and gradually pull into a 45-degree up-line. Once the line is established, roll 90 degrees to the right into knife-edge flight. Hold left (top) rudder to maintain the 45-degree climb.

Step 2. To make the model tumble, apply full left rudder, full left aileron, and full down elevator. As airspeed drops, increase the throttle amount.

Step 3: The goal is to get the model to tumble end over end. The throttle and control surface deflection amounts are critical, as is having the proper center of gravity.

Step 4: After the aircraft performs the Lomcevak, neutralize all the control inputs, establish a 45-degree down-line, and the pull to upright level flight. Return your control rates back to neutral and give the maneuver another try!

It should be mentioned that with the momentum of a heavier aircraft will help to carry it through the figure. If it is difficult to get the tail to swing underneath the model throughout the maneuver, try moving the center of gravity aft a small amount. If this still does not work, increase the control deflections and try different throttle settings. Finding the perfect combinations of all the variables is what the Lomcevak is all about!

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