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  1. #1

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    What's the proper method of a barrel roll?

    I'm flying a 4 channel with what I'd describe as an "average" dihedral. Barrel rolls seem hard, when the plane rolls, it drops altitude like crazy. In experimenting, the only way I've found to even get through the roll is to give it some down elevator. A left roll, for example, gets ailerons at 10 o'clock. I still lose considerable altitude by the end of the roll. I've even moved the aileron throw to give me maximum response. Am I doing this right? Is it just the dihedral that's fighting me, or am I missing something?

  2. #2
    Live Wire's Avatar
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    RE: What's the proper method of a barrel roll?

    Your CG will affect your roll, forward faster and rearward slower. Don't make to large of a change till you feel what you are doing. You never get a true roll, you will have some arc in your roll to be scale. you also need control movement to counter act forces on the plane.

    What type plane do you have, that could make a difference
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  3. #3

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    RE: What's the proper method of a barrel roll?

    I'm no expert , but a 1/4 roll would require some top rudder , then when inverted some down elevator , then 3/4 some top rudder again. Now I fly about 12 planes and am not a real great pilot yet , so some of mine roll so fast that I don;t need any other input , and some are slow enough that they require some down elevator. I'm not good enough to work the rudder into a roll yet so my rolls look like "barrel rolls" sometimes. One of my planes can roll slowly perfectly without any other input. A couple of them are so bad like yours that I just don't get them to roll at all (they do have dihedral)

    A couple of things that may help is to move the CG back or possibly practice inverted straight flight and then practice knife edge with rudder. I've been practicing knife edge and I hope it helps me with slow rolls to make them perfect. It takes a lot of practice for me at least.
    and airplanes were in

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    RE: What's the proper method of a barrel roll?

    The title of the thread is about doing a barrel roll, which is different from an axial roll. Maybe the OP really wants to do axial rolls? A barrel roll looks like the plane is rolling as it follows the shape of a long barrel or pipe. Axial rolls look like a plane rolling on a string. Just curious which one the OP is after.
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    RE: What's the proper method of a barrel roll?

    I guess axial rolls are what I'm really trying to do, sorry for the incorrect terminology. Barrel rolls, as you describe, sound even more difficult.

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    RE: What's the proper method of a barrel roll?

    Yea, I thought he really wanted a roll , not a barrel roll.
    and airplanes were in

  7. #7
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    RE: What's the proper method of a barrel roll?

    With my trainer I get better rolls by nosing up before throwing in the aileron. Sometimes I'm coordinated enough to apply down elevator at the right time and sometimes I'm not.
    - Carrell

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    RE: What's the proper method of a barrel roll?

    And the type of plane will still make a difference!
    Larry K
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    RE: What's the proper method of a barrel roll?

    It's a Parkzone T-28 micro

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    RE: What's the proper method of a barrel roll?


    ORIGINAL: carrellh

    With my trainer I get better rolls by nosing up before throwing in the aileron. Sometimes I'm coordinated enough to apply down elevator at the right time and sometimes I'm not.
    That's the way Ilearned them with a trainer. Start slightly nose up and blend in some down elevator once mostly inverted. In a slow roll (a beautiful maneuver) you also have to work in rudder to keep the nose level.

    You can get fancy and limit the amount of down elevator with aileron differential to make a roll more axial.
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    RE: What's the proper method of a barrel roll?

    A T-28 shouldn't have any trouble rolling well. Set your ailerons to give you a full roll in maybe 2 seconds. That's fast enough that even if you totally botch the maneuver you'll still be upright in time to save the plane. Start learning by giving the plane a bump of down elevator while it's inverted. If you can visualize clock number positions give it maybe half down elevator from 8 - 10 o clock. You'll have to play with how much it takes, but you should be able to go all the way around without losing any altitude or changing your heading left or right. Once you can do that, back the aileron throw to give you roughly a 3 second roll, then work on feeding in that down elevator smoothly so that you're at maybe 15% down at 8:00, 40% at 9:00, then 15% again at 10:00. The actual amounts will vary from plane to plane, but hopefully you get the idea. Many planes benefit from feeding in a touch of down elevator early to offset the tendency to pull to the canopy in knife edge so maybe it's 10% at 7:00 or thereabouts for your particular plane. Once you have that figured out, the next step is to do slower rolls and use the rudder at 6:00 and 12:00. When you do that, you'll find that you need a lot less down elevator at 9:00 and everything will be much smoother. At that point, you can fly your rolls as slowly as you want to, even adding in 4 point rolls as you figure out the setup that make them work the best.
    No kid, I said break ground and fly into the wind!

  12. #12
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    RE: What's the proper method of a barrel roll?

    A Parkzone T-28 will never do really good rolls. There is too much dihedral and it has some serious control cross coupling. Running the CG a bit aft and setting up the ailerons with some differential. The aileron moving up should do so about 3/16" more then the aileron moving down. Make sure your ailerons are moving the same from side to side as well. Should be easy to do depending on your TX. To equal the movenments use ATV. Being a Parkzone I am going to assume Spektrum. Go into ATV for Aileron and adjust the right aileron so it travels the same up and down. Next do the same for the left aileron. It will be adjusted with the flap ATV. Now go into the Diff menue and adjust about 12% aileron diff. It will roll better after these adjustments. Moving the CG aft will make the airplane require less correction when inverted and that will smoothen it out some too. Then it's all a matter of practice. If you can get decent rolls out of the T-28 then something like an Extra or Yak will be a peice of cake.

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    RE: What's the proper method of a barrel roll?

    Thanks for the advice, jester and speedracer. I am a beginner, so I do not yet have a TX that allows me to make the adjustments you recommend, speedracer. Hopefully one day. Without measuring, though, I can visually see that the ailerons are not moving identical to one another, they're quite off. I imagine that, plus the dihedral, are working against me.

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    RE: What's the proper method of a barrel roll?

    If you have more up than down aileron movement, that's actually helpful. You can get differential with your mechanical setup also if your radio doesn't have that feature. The differential keeps the plane from doing an uncommanded yaw when you apply ailerons, and it's part of every trim process for every plane. To get differential without using your radio, set the servo arms to point toward the front by one or two teeth then lengthen the push rod to get the aileron back to neutral. Because of the geometry change, you'll now have more up travel than down travel, even though your radio is commanding equal travel to the servo. It takes some experimenting to get it right, but the test is to fly the plane away from yourself and roll left and right quickly maybe 15 degrees each way. If the tail wags while you're doing it, you have the wrong amount of differential set up. If it holds steady, you have it right. If the tail moves the opposite direction of the roll, you need more differential. If it moves the same direction, you have too much. Once you get it right, you'll find that rolls get smoother as do you standard turns.
    No kid, I said break ground and fly into the wind!

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    RE: What's the proper method of a barrel roll?

    Actually, I have more down aileron than up.

    I understand what you're saying, but my ailerons are controlled by one "short throw" servo that is simply a small motor that turns a gear. That gear moves an arm that swings a plastic piece left or right, thereby moving ailerons. I've thought long and hard about how one might adjust such an aileron servo as that, and cannot figure it out. I don't have an "arm" that can be adjusted.

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    RE: What's the proper method of a barrel roll?

    He has the UM T-28. Its not very receptive to modifications or adjustments. It is basically a little fun flyer and not meant to be an aerobat. I have one and its a blast to fly, but very limited in its performance.  It will do a basic barrel roll, but not an axial roll, its too light, has belly weight from the battery, and the thin wings have a good dihedral on them.   The tiny electric motor doesn't torque the fuse either, so no assistance from that.    There is not a lot of throw on the ailerons either, and they are rather slow.
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    RE: What's the proper method of a barrel roll?

    One shouldn't have to introduce rudder or elevator to perform a conventional axial roll. The roll rate would be fast enough where you couldn't provide rudder or elevator inputs fast enough. On a point roll (four point or six point) or a slow roll, to keep the appearance axial, you would have to apply small amounts of elevator or rudder with each orientation change to keep the aircraft tracking properly.

    Generally speaking, any type of model that is not designed for aerobatics will require control inputs to compensate for aircraft elements that are ill-suited. A trainer for example, generally flies too slow, has a non-symmetrical wing (lift properties differ right-side-up versus inverted) and has significant dihedral for stability and self leveling characteristics. All of these factors work against performing an axial roll. Similarly, many WWII warbirds also have undesirable characteristics for precise aerobatic maneuvers. So, as a previous poster pointed out, the airplane and how it's set-up has a great deal to do with it.

    In fact, a barrel roll is a hallmark characteristic of a warbird. They typically will dramatically change pitch when entering a roll, thus creating the barreling or spiraling effect. When you give the nose a pitch up before entering the roll (to counteract altitude loss during the roll), nothing looks cooler to me than a nice, long, slow barrel roll.

    My point of view is, don't try to force an airplane to fly in a way that it wasn't designed for. It just makes things look awkward. If you want to do precise aerobatic maneuvers, buy an airplane designed for it. It still takes a good set of thumbs to execute the maneuvers clean and precise. Go to a pattern contest and you'll see guys who spend hundreds of hours a year trying to prefect loops, rolls and spins. Heck, they spend just as many hours working on flying straight and level as the origin of any good aerobatic maneuver is starting from a proper position and attitude in the air.
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    RE: What's the proper method of a barrel roll?

    More down than up is definitely a problem.  That means you will have drag in the direction opposite to your roll direction.  Correct differential was the most important thing to get when I was learning rolls.

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    RE: What's the proper method of a barrel roll?

    You've all inspired and convinced me to put some aileron diff into my SkyFly Max by reading this thread. It yaws terrible even when I make a turn. Makes me remember to use the rudder.
    and airplanes were in

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    RE: What's the proper method of a barrel roll?


    ORIGINAL: 70x7

    I guess axial rolls are what I'm really trying to do, sorry for the incorrect terminology. Barrel rolls, as you describe, sound even more difficult.
    Barrel rolls are quite easy with a trainer. Dive for speed and then start a straight climb of 45 degrees. Before the airplane slows down, feed in aileron and rudder and keep them there until the airplane rolls around back to upright.

    Barrel rolls are a positive G maneuver so you are not feeding in elevator. Just leave it alone as you do a barrel roll.
    For learning axial and barrel rolls, make sure you start on a good "up line". You will get there by just practicing more.
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    RE: What's the proper method of a barrel roll?


    ORIGINAL: speedracerntrixie
    A Parkzone T-28 will never do really good rolls.
    This hits the nail right on the head, plus a "scale" plane like this performing an axial roll just looks wrong. A well performed barrel roll will present much better in the air.

    A large contributer of making scale planes look good in the air is finding out what they do well, and practicing that. From my perspective there's nothing uglier than a scale plane being forced to do something it doesn't want to do and a T-28 doing an axial roll is one of them.

    However if you absolutely must practice axial rolls with it, then the correct technique has been outlined in previous posts, where you need to co-ordinate the rudder and elevator to keep the flightpath straight. I'm a pattern flier who strives for geometric perfection and that constant speed look, but who also appreciates the beauty of a scale plane being flown true to scale which itself is no easy feat.

    Good luck with the practice.

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    RE: What's the proper method of a barrel roll?

    The Barrel Roll
    The barrel roll is often used in aerobatic demonstrations as well as in air combat. It's halfway between a roll and a loop.

    β€’Fly straight and level at 300 ,knots or more. (1)
    Or aprox. 3/4 throttle on your model
    β€’Pull back on the stick to get the aircraft into a 30-degree climb. (2)
    β€’Apply full right or left stick. (3)
    β€’The aircraft should climb during the first half of the roll and descend during the second, or inverted portion of the roll.
    β€’As your wings approach a level position, ease up on the stick and apply a little forward stick to end the maneuver in level flight. Your goal should be to exit at the same altitude you entered. (4)

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    RE: What's the proper method of a barrel roll?

    Arm chair fly the plane or get a stick model, Picture the wooden shape barrel fat in the center trim on the ends, start flying the plane as explained at high altitude let the aircraft do the work, lead it around the shape of the barrel, start with a little roll rate increase it toward the middle of the roll and less toward the other end of the roll or the barrel.

    Then PRACTICE PRACTICE PRACTICE and MORE PRACTICE. It's fun flying scale !!!!

  24. #24
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    RE: What's the proper method of a barrel roll?




    ORIGINAL: 70x7

    I'm flying a 4 channel with what I'd describe as an ''average'' dihedral. Barrel rolls seem hard, when the plane rolls, it drops altitude like crazy. In experimenting, the only way I've found to even get through the roll is to give it some down elevator. A left roll, for example, gets ailerons at 10 o'clock. I still lose considerable altitude by the end of the roll. I've even moved the aileron throw to give me maximum response. Am I doing this right? Is it just the dihedral that's fighting me, or am I missing something?
    Welcome to aviation: To assist you with your rolls, etc. I will explain a couple points that have been hit on above but think of this. The airplane has a wing providing lift. Wing angle of attack, (AOA) (not incidence) is one of the main items in the Lift Equation. Airspeed is the major factor in that equation, and both items are controlled by the pilot. Gravity is trying to change your desired position.

    The pilot, flying the airplane in straight and level flight has set the factors for that task. The elevator is holding the wing in the proper AOA to establish level flight. Any change of the throttle or the elevator changes the established level flight. Now what happens when you roll is that the previously established upright flight inputs are moving the aircraft to a direction as pulled by those inputs. YOU as the Pilot-in-Command then change those previously established inputs to change the new established situation. Basically, any airplane trimmed for normal upright "war against gravity" will need some elevator inputs during the roll or Gravity wins.

    A Barrel Roll is a whole 'nother ball game. It is a roll about some point away in the distance. In USAF's training (many years ago) it was accomplished by establishing a point way in front, at about 20* nose down. Then roll to 90* bank (IIRC) to start a turn then a rolling turn around the point. At upright level flight you would be to the side the same distance as you started below the point, then continue to a 90* bank the same distance ABOVE the point then to a same distance away when passing the inverted level flight then rolling and pulling down to the original point. Recover to level flight. There is a continuous change in pitch and roll throughout the maneuver.
    So you can't be lazy! HA!

    Now who will be the first to visualize those 4 points and tell me which point is where the airplane is at its highest ALTITUDE? Of course you know that it is at the Inverted Level Flight. Drawing the 4 points on paper can fool you. As a flight instructor for 3 years in the USAF T-33 and then 2 years in the T-38,, again many years ago I "been there done that".[8D]

    So 70X 7, I hope now you are thinking, "I MAKE this flying machine do WHAT I WANT it to do!" Best of luck to you.
    Horrace Cain AMA L-93

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  25. #25
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    RE: What's the proper method of a barrel roll?

    Horace, glad to see someone else who really knows how to do a barrel roll. Naturally, you were an Air Force IP. I was a Tweet IP for 4 years back in the 1960s. No one even knows what a section line is any more. Man, that was a lifetime ago.
    Ed Moorman, AMA 553, Former R/C Report Fun Aerobatics Columnist. 76 and up to my old tricks!


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