|Apr 30, 2011, 02:53 AM|
You need to put up with a whole lot of ugly before the goodness starts happening.....
THE KEYS TO 3D
- The lower (lighter) the wing loading the better: lower stall speeds and better knife edge capability. The ability to fly away from a botched maneuver is important.
- The higher the power to weight ratio the better: blast out of trouble or jump out of a hover.
- The more the control surfaces move the better: faster maneuvering.
- The larger the control surfaces the better: more control of the air.
- The more powerful the servos the better: to prevent flutter.
- Digital servos: precise motion throughout the range and tighter centers.
- The faster the servos the better: faster corrections.
- The larger the fuselage side area the better: better yaw control.
- The larger the size the plane the better: less sensitive.
- A computer radio: mix out quirks, switch rates easily using one condition switch.
- The correct amount of right thrust: the plane must go up straight in a hover.
- Lots of money: buy the best, stretch the envelope, have a backup.
- Nerves of steel: the lower the better.
- Bulletproof airframe: don't have a mechanical failure, especially servo linkages.
- Bulletproof engine/motor : hovering on the deck has an unhappy ending if the engine/motor quits.
- Rearward CG: flies inverted virtually hands off for better manoeuvrability.
- Extensive preflight: you can't afford a mechanical failure in the air which should have been caught on the ground.
A 3D Pilot Will:
Fly with awesome precision.
Fly a straight and level line, even in high wind.
Always fly parallel to the runway. Don't drift and don't purposely fly skewed to the runway.
Either fly straight out or straight in or circle out or in.
Always be flying maneuvers, never just flying around aimlessly.
Be acutely aware of the wind direction and speed to compensate with rudder and throttle.
Have a plan on what to fly before taking off.
Always be a better pilot after each flight by paying attention to details and learning something each flight.
Fly maneuvers gracefully and at constant speed with the same quality both upwind and downwind.
Fly all maneuvers under control at all times. While some maneuvers may scare the casual observer, other pilot's familiar with your flying will be amused.
Practice a lot.
Roll and snap to the left as well and as often as to the right.
Present manoeuvres properly by centering loops, rolls, Cuban 8's.
Go home with plane intact.
How about a lesson in 3D ?
Just to get started. It seems that everyone that is on the fence about getting started in this flying style usually wonders about the basic hover, by this I mean to hover an airplane on a vertical axis in a still position (hanging on the prop). In this maneuver I consider to be the basic of basics (although some would disagree and say the basic of the basics is the harrier, but everyone has an opinion and they are entitled to that as a human). Now the assuming that the setup on the airplane is aerodynamicaly neutral (upright and inverted flight flys the same, basically but I will go over that in another post because that is a long discussion) and you have at least a 1 to 1 weight to power ratio (preferably a 2 to 1 ratio because this will save the beginner alot of headache and make this maneuver much more forgiving).
Start out into what is called a wall. This is too easy, it is just a maneuver to get the aicraft into a vertical position. At strait and level flight, at a medium speed (like a landing speed but hot) making sure that your wings are upright and absolutely level pull full up elevator as you reduce throttle to about a quarter of your engine power (I said power not stick position) this will take some getting used to but learn to use that left stick and manage power. When the aircraft gets to that verticle position release the elevator to neutral and begin to increase the power just enough to keep it from falling and not too much to keep it from rising.
Now we are in a hover so heres where it gets a little tricky and is where most hit there mental wall here (so 99% of folks listen up, the other 1% are probally laughing at me right now for talking too much about the wall). All we need to understand are the forces acting on the aircraft and what we have to work with to control these forces.
First of all we need to manage the power. Once we have the correct power level to hover all we need is a click or two on the throttle stick to make corrections. That being said the more throttle we have the more control athourity we have on our control surfaces due to the amount of air moving over the surfaces. As we increase power we have just induced torque in the airfraime causing the plane to roll to the left which brings us to the next step.
Right aileron. We will counteract this left torque by applying right aileron (too easy) but remember what I said about increasing power, if you increase power without applying a little more right aileron you will start to roll left, decreasing throttle without reducing the amount of right aileron you will start to roll right (clear as mud?). When starting out lets keep the aircraft with the top towards us for orientation purposes.
Rudder this is now our vertical axis right and left control(assuming that the canopy is facing us). You will find that if the engine thrust line is basically correct you will still need a little right rudder, again to counteract engine torque. Be careful not to let the aircraft get too out of wack on the yaw or you will be traveling all over the place trying to "catch up with it" (we all do it starting out so dont get discouraged).
Elevator control. This usually stays pretty effective in a hover, so all we are doing here is keeping the towards and away axis in check (again assuming that the canopy is towards us). It is very importand to keep this axis in a vertical position throughout this maneuver because if we dont we will induce what is called wing rock (another disscussion) simply said the wings will rock side to side and you will be fighting your rudder the whole time.
Now we are not only in a hover, but we are controlling it for more than a half a second that most folks do. I will say this, If you are trying this far away "dot range" you will not see the minor corrections needed to keep it controlled. Also if you are too high this has the same effect. Im not saying you should start out head high or lower (although it does save damages to a minumum on a lighter airplane in case of an unfortunate "dumb thumb") but at least so you can see the aircraft good enough so you can see the control surfaces move.
You've seen this “new” 3D flying, maybe even tried some but if you're like most flyers you really don't know exactly how to do it. In this article I’ll let you in on my tips, tricks and secrets that I’ve taught myself over the past few years of flying 3D. 3D is most often defined as ‘purposely flying an airplane in a fully stalled, yet controlled condition where-in the propeller thrust alone is generating the balance of lift keeping the airplane aloft.’ 3D is at the top of the Extended Flight Envelope surpassed only by 4D in which airplanes are out-fitted with a reversing-pitch prop allowing it to fly backwards and even hover nose-down for a short time!
So you have a plane that’s over powered and your brave enough to pull it vertically and hang it on the prop for a few seconds before it falls of to the side and plunges earthward and you think that’s something! Well that it how 3D most-likely started, but just because your airplane can prop-hang doesn’t mean it is a “3D plane”. Any aircraft with enough power can prop-hang but prop-hanging isn’t hovering nor is it “3D”. Flying 3D takes more than a 1:1 thrust to weight ratio. It also requires huge control surfaces and throws from those surfaces, the correct wing platform, Center of Gravity and an ability to carry some inertia. Without these an airplane cannot perform 3D maneuvers, at least not well. The wing and horizontal stabilizer need to be very close to in-line with the thrust line. The CG has to be quite aft and very centered laterally as well as vertically on the aircraft to fly 3D well so that the pilot doesn’t have to fight the airplane into and out-of maneuvers or transitions. Setup and balance is the second most important thing for 3D next to a lot of power.
The proper setup can make or literally break a 3D airframe. The difference in performance between a properly setup plane and a poorly setup plane is night and day! We’ll start with the nose and work back. The motor, which you need a lot of, enough to have at least a 2:1 thrust over weight power ratio, needs to have proper down and right thrust. 2* down and 3* right is a good starting point because unlike a regular sport aerobat you are swinging a much larger prop, there for there is more torque and its compounded that much more do you the RPMs the engine can swing the prop, the high Angles Of Attach you’ll put the airplane through and the fact that the airplane is usually flying only on the propeller so the torque effects and P-factor are much more prevalent and apparent. There is no way to eliminate the prop effects, but you can bring them to a minimum with the correct down and right thrust. The prop is another huge performance item. You need a very large and low pitch prop. This will create more thrust over a smaller and higher pitch “bench” prop. If you have too much pitch your prop will “cavitate” while in low-airspeed high throttle flight making you loose lots of thrust and prop wash. As we move back, we come to the wing, which as I said should be in-line with the thrust line (which is also the middle of the prop and drive shaft). If the wing is too high or too low it will not do a lot of maneuvers well, nor will the ailerons receive good, smooth airflow from the prop wash. With the wing too high or low the knife edge coupling will also be very bad, so much so that the pilot would have to concentrate more of flying the KE, rather than doing the maneuver. And not to be forgotten, the airfoil HAS to be symmetrical to fly 3D maneuvers well. Next in line would be the CG. This is more critical than anything else for good 3D abilities next to having enough power to do them. The 3D CG is usually 30-40 percent of the wing chord as measured back from the wings leading edge at the root. The components of the airframe also need to be situated so that the CG is not only balancing the airplane fore/aft, but in the lateral (side to side) and vertical (top to bottom) plains as well. Centered as close to the middle and at the thrust line as possible. It likely cannot be perfect, but it can get very close. Your plane needs to be balanced so that it will fly hands off at half throttle (50% power) upright or inverted (upside down) without the need for elevator trim. It should feel very neutral and somewhat buoyant if the CG is correct. When properly balanced your plane should fly with only VERY minimal, in any trim inputs, strait and level, RSU or inverted at half throttle. Next come the ailerons. They need to be very wide and extend from the root to the tip, if not you will not get good prop wash over them and they will be stalled along with the wing in high alpha attitudes. They need at the very least 45*of throw, but about 60* is the norm for a good 3D plane. The tail moment (length of the tail fro the wing’s trailing edge to the horizontal stabilizer’s leading edge) is next. 3D planes are usually short coupled, meaning the tail moment is short. If the moment is too long it will not flip and pitch fast enough, or at all which will make most all 3D tricks un-doable. But if the moment is too short it will be so sensitive to pitch changes that it will be too hard to manage in most maneuvers even for a competent 3D pilot. A good “rule of thumb” for the shortest tail moment would be about the length from the prop to the CG, any shorter and it may be too short. Next is the fuselage inside the tail moment, which isn’t a big deal, but having a tall back, like a turtle deck, gives the plane more fuselage area to “fly” on during knife edge (KE). Last but not least would be the tail feathers. The stabilizers should be attached very well but not be too large as compared to the size of the control surfaces. If they have too long of a chord they will do more to slow the rotation of the plane rather than aid it. Some 3D airplanes don’t even have any horizontal or vertical stabilizers. The elevator and rudder are “flying” in that they are hinged on a pivot on the fuselage. The whole horizontal or vertical stabilizer will move! This is something really cool, but not required at all. The control surfaces, both rudder and elevator, have to be quite large with at least 45-60 degrees of throw. Anything less and it will be very hard to do most 3D maneuvers. For good KE the horizontal stabe must be very close to in-line with the wing or just below it for low-coupling. The rudder does need to be large, but not too tall. If the rudder is too tall or has too much counterbalance the rudder could roll the airplane as much as make it yaw, which would make KE and lots of rolling maneuvers very hard to do because it would tend to over roll the airplane, but not roll it enough so that the ailerons wouldn’t be needed. You’d be fighting with the ailerons to counter the rudder’s roll effect rather than make the airplane roll axially. Keep all these in mind when searching for your 3D airplane.
As a competent pilot you have to be able to control your aircraft at all speeds and attitudes with all four controls, The aileron, elevator, rudder and throttle. Without than ability, learning 3D will never happen for you. You have to be a “two stick” pilot in that you HAVE to know how to fly an airplane with all four controls, where as most sport/Sunday fliers rarely use the rudder or manage the throttle. They just nail the throttle on takeoff, hoping it the takeoff is quick so it doesn’t get “squirrelly” then they bank and yank until they are out of fuel or get board, then chop the throttle and head for what they hope is the middle of the runway and fly the airplane to the ground, hopefully onto its wheels during all three or four bounces/skips before it rolls to a stop either at the end of the runway or off the side. Sound like you? Well, try flying around using your left thumb before you try some 3D. Even the most basic 3D maneuvers and tricks take good rudder coordination. To gain a quick sense of using the rudder, fly your trainer or most basic sport model making good use taxing the model, making long takeoff roll outs before lift off keeping the model down the center of the runway using your rudder. Make coordinated turns and circles. Try some flat turns, where-in you fly in a circle while keeping the wings level the whole time with your ailerons but using your rudder to make the turn. Try some forward slips and maybe some knife edge. After you’ve got confidence in flying those maneuvers concentrate of cross-wind landings, forward slips to landing, and then graduate yourself to rolling circles. Practicing rolling circles will really aid you in learning to coordinate all three controls and will progress you easily into rolling harriers and rolling loops!
After getting friendly with your left stick and rudder anyone can now teach themselves to fly 3D! But first you need a good model. Not just a good 3D capable plane, but one that is cheap and durable. The best way to go is either with a FFF or EPP foam airframe, like Twisted Hobbys Crack Yak or Crack Pitts or hobby king’s EPP Yak 54 profile, All are very good 3D trainers and super cheap and can be flown with very in-expensive gear. Just like learning to fly, you WILL crash! Just stay at a comfortable altitude and done be afraid to bail out of a maneuver early or just “pan-cake” on the ground. Keep some hot glue or CA around! ; )
Most 3D maneuvers are not specifically derived from standard aerobatic/IMAC maneuvers. They are a breed of their own but a good knowledge and ability to execute standard maneuvers will help to say the least. I’ll list the known 3D/Freestyle maneuvers starting with the easiest to the hardest to perform.
Harrier - A very slow forward flight motion with a high Angle Of Attack. One can fly strait or circle using the rudder to turn the desired direction and opposite aileron to rudder to keep the wings level, using throttle to maintain the desired altitude. Find the AOA your plane likes best, which is where you still have aileron control without the wings rocking back and forth.
Inverted Harrier - The same as the above, just inverted. Most capable pilots find this easier than a standard harrier due to the wing being above the CG. It tends to have less wing rock, but your rudder and aileron inputs are reversed, and there is a fair amount of “pucker factor” seeing your plane’s tail so close to the ground and the landing gear above it.
Elevator - This is just a descending harrier. You can make it as steep or gradual as you are comfortable with by using your throttle, again find a good AOA where the wing doesn’t rock. This can also be done in Knife Edge or as a rolling harrier!
Flat Spin - A spin induced with full elevator, full rudder, and aileron. Once the spin is initiated you will level the wings with the ailerons and increase engine speed a bit to pull the aircraft around. This will in turn flatten the spin. The wings HAVE to be FULLY stalled to get a good and level axial rotation. Not necessarily a 3D maneuver by most 3D pilot‘s definitions, but you have to know how to do one properly to do some 3D maneuvers.
Knife Edge Spin - Its easiest entered from a vertical climb. Add full LEFT rudder at the top just before the stall and let the plane rotate 270* then apply throttle and full down elevator, your plane might require aileron input as well to keep the wings perpendicular to the ground. This will throw you into a type of falling lomcevoc where in your plane is tumbling over its pitch axes. Its just a flat spin turned on its side. Manage your power to make the spin as slow or as fast and violent as you want.
Hover/Torque Roll - A hover is a controlled prop-hang in that you are holding your airplane vertically without any apparent movement or motion, forward, backward, sideways or up/down. You pull the aircraft into a completely vertical attitude and allow the propeller to hold the airplane in the air like a helicopter. One can keeping the wings from spinning by adding right aileron or just let the plane spin on its own because of the torque from the prop, which is a torque roll. When first learning most pilots find it easier to induce a slightly faster spin/roll. This will minimize the time the belly is towards you, which is that hardest part of hovering/torque rolling.
Wall and Alien Wall - The Wall maneuver is where your plane starts from a horizontal flight path and immediately transitions 90* into a vertical climb, as if it were rolling along the ground and hit a wall and started to climb the wall. An Alien Wall is the same only much more violent (like a “UFO” sometimes seems to do) in that it is entered with much more airspeed and G. This maneuver is usually immediately ended in a hover or a waterfall.
Pin Wheel - This is a simple maneuver but it requires a lot of power and very rearward CG and a ton of rudder to complete properly. Start from a hover, yaw to the right a few degrees then simultaneously add full right rudder and full power to complete at least one full axial rotation around its CG as if the plane were stuck onto a pinwheel and spun. Some aileron input might be needed to keep the plane from falling out into a flat spin and a touch of down elevator can make it rotate a little faster.
Snap/Pop up ! - The Snap-Up is when the airplane comes to a hover from a horizontal flight path with a snap-roll in the middle. Basically a wall with a snap in the transition and ending immediately in a hover. Try not to over rotate the snap roll, just initiate the snap with the usual full elevator, rudder and aileron but half way thru the snap neutralize the elevator then stop the rotation by neutralizing aileron and rudder, then pull full up with a burst of power to finish the vertical transition. It reads harder than it actually is. A Pop-Up is the same maneuver only without the snap.
Waterfall - The waterfall is a maneuver where the plane pivots 360 degrees over it’s pitch axes with very little forward motion and altitude change. This maneuver takes either a lot of power or inertia to complete. It can be finished with just one flip/rotation or multiple rotations. It is usually done “on the outside” with down elevator which is easier because its not fighting prop torque.
Yo-Yo - Entered from a hover or wall, power out vertically to gain some altitude (not too much) then enter a ½ waterfall. The plane will flip around into an inverted elevator, let the plane fall back to the ground and power up and do it again. This maneuver looks best doing it two to three times making the loop smaller and lower each time, ahh…like a Yo-yo!
Falling Leaf/Tic-Toc - From altitude enter this maneuver from a roller coaster, harrier, hover, or just slow the plane to a forward and level stall. Push the plane over onto its back with a burst of power, then immediately onto its belly with another quick and hard burst of power. Do this several times in a row, like a leaf flopping slowly to earth from a tall branch. Try to keep the plane parallel to the ground so you don’t over rotate into a waterfall. You may need to use right rudder with the throttle bursts to keep the plane strait.
Pogo - This is another hovering maneuver. Rapidly climb and then descend (tail slide) in a hover as if the plane were riding a pogo stick! Its most often done in a hover, but some better than I can do a torque rolling pogo too!
Snap Rolls -The snap roll is commonly used when flying 3D so I will add it to the list. The Snap Roll by AMA aerobatics code definition is "a simultaneous, rapid autorotation in the pitch, yaw and roll axes in a stalled wing attitude." Now, to do a snap roll there are some things the plane must do.
1. You first need to sharply increase the angle of attack to put the plane into a position where it will stall without changing the track (much) This is easier said than done but a little nose break is really necesary to get a good snap and hold your line. This is done with a quick pulse of up elevator to "break" the nose and put the wing in a position to stall.
2. Within a split second of that pulse of elevator input you push the rudder full over (to start learning to snap) and at the same time input full aileron deflection in the same direction as the rudder.
**What you should see then is called "rapid autorotation". When you input the rudder you get "YAW" which means one wing speeds up, and the other slow rapidly and stalls. This initiates a sharp roll in the direction of the rudder input becuase one wing stops flying. Technically you should not "Need" to use ailerons, but with RC models the ailerons help to get the process started. You should not be depending on the ailerons for the rotation, if you are its not snapping they are just there to clean it up a little.
3. To keep the plane on heading as stated about you neutralize the elevator 1st and then the ailerons and rudder. All of this happens in less than 1 second.
Initiate stall in the wing by sharply pitching.
Stall the wing by inputting the rudder
Ailerons to clean up the rotation.
Neutralize at just the right moment to stop roll.
It is sortof a J pattern laid on its side.
Tail Slide - Bring the plane into a vertical climb/hover then reduce the throttle to below that at which the plane hovers and by controlling the slide backwards strait down with backward control inputs bring it back down to its starting altitude or below that even. It is very hard to do and nearly impossible to complete if you chop the throttle completely because there will be no prop wash over the surfaces to keep the plane from toppling over nose first.
Harrier Roll - Like the Harrier maneuver only roll combined and performed simultaneously in flight. Its not so hard, it just takes a little practice to get the pattern down. If rolling to the left use LEFT aileron and begin the pattern of RIGHT rudder, DOWN elevator, LEFT rudder, UP elevator and repeat. After you get the pattern down you can “come in” a little early on the pattern to get the plane to harrier roll in a right hand circle or one can come in late to make a left-hand circle. Most pilots find it easiest to continuously bump the throttle during the maneuver to keep the roll rate and altitude under control.
Rolling Loop - Using the same technique as the rolling harrier add full power to make your up-line and pull the power back as needed to make the top of the loop round, on the down side you’ll have to get over the pucker factor and really work your thumbs because you’ll have to apply near full power again on the last quarter of the loop to get it to come out and not smash into the ground, but too much and it will come out of the loop too quickly and the loop will not be round.
Parachute - This maneuver is a vertical diving roll that virtually stops its descent as it instantaneously enters into flat upright position. The transition has to be very quick so that the inertia continues to push the plane strait down (as if it deployed a parachute and it floating down) instead of flying out of the maneuver in an elevator.
Panic - The Panic is simply the parachute maneuver only ending with the plane inverted and much closer to the ground.
Blender - This maneuver is like the previous only ending in a flat spin. I’ve also seen it done ending in a KE spin instead of a flat spin.
Blaino Draino - Start from straight and level, pull vertical to a fair altitude and chop throttle, pull full elevator to flip back over for a vertical plunge. Roll the plane until your close to the ground then quickly stop the roll about 1 mistake high and pull full up elevator with full power all at the same time making the plane instantly transition into a harrier with rudder getting very close to the ground. It can be exited immediately into a hover or waterfall, or any maneuvers that start with a nose-high attitude.
Roller Coaster - This is basically a horizontal falling leaf, starting from slow level flight pitching the airplane strait down then strait back up then strait back down again. If you enter it with too much forward speed you will over rotate and into a waterfall, not enough speed and you’ll not have enough forward inertia to make at least one down, one up and one down pitching sequence before your plane is no linger moving forward.
Terminator - Its when the plane is flying straight and level and then makes a sudden 90* dive straight down. When the plane gets close to the ground pull out suddenly and fly out of it with full power, think of the exit as a wall on its side, the ground being parallel and only a couple feet below the imaginary wall your driving you plane on.
This is just a selection of 3D manoeuvres there are many more out there that are signature moves of professional RC pilots or combinations of these. Like everything in life and especially in this hobby it all just takes practice. Set a goal for each ~10 minute flight to learn ONE maneuver and become confidant with it before moving onto another. Once you feel comfortable flying all these moves try stringing a few together in one short sequence of 3 or 4 tricks. After you can do all 3 or 4 in a row consistently try adding a couple more at a time until you have a 4 or 5 minute routine put together! This is very fun and as challenging to do as it is to learn the moves themselves. Note that no plane can just jump from any one move to another! A 3D pilot has to manage his airspeed and airspace so that too many G’s aren’t pulled or so you don’t drive right into the dirt! For example you can’t go from a panic strait into a falling leaf or you’ll fly right into our archenemies, the earth! Try doing a rolling loop into a wall, then into a tail slide. Or try a wall into a waterfall, then into an inverted harrier. Do not enter a violent maneuver with too much forward speed, for example a panic with too much throttle on the down-line. When the plane reaches the point of the transition it will either over rotate or you could just blow the wings right off. One can’t enter a quick maneuver without enough speed/inertia, which will likely only have the consequence of not being able to complete the maneuver and making you look bad. Unless you are too close to the ground, for example; you do not have enough airspeed to finish the bottom of a rolling loop, try splicing maneuvers together as well, sometimes called 3F, or Flip Flop Flying. Cut maneuvers short or in half and immediately transition into another, for example: A half rolling loop into a Terminator at the top, then throw in a falling leaf or harrier roll at the bottom of the Terminator. Keep the “down time” or “setup time” between maneuvers minimal. This will keep your adrenaline, heart and your thumbs pumping and the peanut gallery on their toes!
3D Video Tutorial Compilation.
3D CLINIC VIDEO #2b: Flat Spins and Blenders (5 min 4 sec)
BoneDoc's 3D Clinic #2b: Flat Spins and Blenders (5 min 4 sec)
3D CLINIC VIDEO #10a: Walls, Tumbles, & Waterfals(TX Overlay) (7 min 56 sec)
HobbyKing 3D - HOW TO FLY 3D w/ Michael Wargo Part 3 - Waterfalls & Flat Spins (7 min 36 sec)
BoneDoc's 3D Clinic #1: Harriers, Upright and Inverted (8 min 42 sec)
3D CLINIC VIDEO #1c: INVERTED HARRIER #1 (7 min 0 sec)
3D CLINIC VIDEO #1b: UPRIGHT HARRIER #2 (10 min 19 sec)
HobbyKing 3D - HOW TO FLY 3D w/ Michael Wargo Part 2 - The Harrier (7 min 51 sec)
BoneDoc's 3D Clinic #1d: Harrier Tips from Ben Fisher of 3D Hobby Shop (9 min 1 sec)
BoneDoc's 3DCLINIC #14a Harrier Landings (5 min 45 sec)
Wamsy's 3D Tutorials: Basic Turnarounds (3 min 3 sec)
HobbyKing 3D - HOW TO FLY 3D with Michael Wargo - Part 1 -The Knife Edge w (6 min 46 sec)
3D CLINIC VIDEO #3a: Knife Edge Flight - The Basics (TX Over (4 min 54 sec)
3D CLINIC VIDEO #3b: Knife Edge Flight - Advanced (6 min 28 sec)
BoneDoc's 3D Clinic #2c: Knife Edge Spins - Revisited (5 min 6 sec)
RC Lesson - Knife Edge Slide (1 min 12 sec)
RC Lesson Tic Toc Loop (0 min 46 sec)
3D CLINIC VIDEO #4a: Hovering ... DOD (7 min 45 sec)
Michael Wargo - HOW TO DO 3D Series Part 4 -Hovering and Torque Rolls (14 min 5 sec)
3D CLINIC VIDEO #11a: Torque Rolling(TX Overlay) (6 min 35 sec)
3D CLINIC VIDEO #11c: Torque Rolling(TX Overlay) (4 min 28 sec)
BoneDoc's 3D Clinic #13a Precision Rolls (5 min 19 sec)
Bonedoc's 3D Clinic Video #9a: 4 Point Roll (5 min 4 sec)
Bonedoc's 3D Clinic Video #9b: 8 Point Roll (3 min 25 sec)
BoneDoc's 3D Clinic #22: The Pop Top (5 min 54 sec)
Pop-Tops with Slow-Motion (2 min 22 sec)
Rc Lesson - Pop Up (0 min 53 sec)
How to Lomcevak (4 min 8 sec)
BoneDoc's 3D Clinic #12: Power Consumption Through Different Maneuvers (3 min 43 sec)
RC Lesson - The Snake (0 min 51 sec)
Wamsy's 3D Tutorials: The Snake (2 min 41 sec)
Mark Leisberg Harrier Rollin (4 min 40 sec)
3D CLINIC #21 - Rolling Harrier (preview) (0 min 26 sec)
BoneDoc's 3D Clinic #5: Rolling Harrier (9 min 43 sec)
Rolling Harrier Tutorial (8 min 40 sec)
BoneDoc's 3D Clinic: Rolling Harrier 101 (7 min 17 sec)
Bonedoc's 3D clinic Advanced Rolling harrier (Latvian and Russian subtitles) (6 min 7 sec)
BoneDoc's 3D Clinic 23: Rolling Harrier 102 - Directional Control (5 min 29 sec)
Rolling Harriers with Stick Movements (1 min 10 sec)
Rifle Rolling Harriers with Slow Mo (1 min 47 sec)
Voro's 3d School: Rolling Harrier Tutorial (7 min 31 sec)
FLYINGGIANTS.com - BoneDoc's 3D Clinic - Rolling Harrier Spin / Weeble Wobble (Standard Def) (5 min 41 sec)
3D Tutorial: Weeble Wobble (3 min 5 sec)
Wamsy's 3D Tutorials: Rollings Loops (9 min 53 sec)
How To Do 3D - Knife Edge Coupling Issues - Programming Radio (21 min 9 sec)
Bonedoc's 3D Clinic Knife edge mixing (Latvian and Russian subtitles) (9 min 51 sec)
Rollers by theKM (Arron Bates)
Rollers... both straight and turning... thought I'd make a diagram of what the goal is. There are ways of cheating, like, generally maintaining height and then bumping elevator to get into the direction you want to go... but, if you get the rhythm of a good well separated stir, with enough practice this is what you will end up with...
...rolling manoeuvres are all about controlling your tail input into a direction relative to the roll. The diagram shows rolling left and right, and also shows what we mean by "earlier" timing, and "later" timing. To fly a straight roller the control target is straight up only because we're fighting gravity. To turn, we're fighting gravity as well as adding a direction to the control target. If you can nail a control target to wherever you want on the orientation of the roll, you can fly any rolling manoeuvre there is. Figure 8 change overs for example "simply" put the control target on the other side of the roll...
for the control target, if you can bring the control surface to point in the direction of the red bar when it starts, and let off when it ends, this will result in a really smooth roller. Even if you can't nail the exact start and end, if the average of your input is centered on the center of these red control target bars, then you'll still end up with a nice roller.
the "turning turning the same direction as you're rolling" is typically harder because you need to change your timing to be very "late"... and when you learn it's tough because you can come on too late, hold it too long, and the plane ends up diving. because you're not giving enough attention to also fighting gravity. Turning the other way is typically easier as we're fighting gravity as usual, and the turn happens simply by coming on earlier... if we don't get there quick enough the plane simply climbs, which is nice.
...this is all easier said than done, takes a year or two to get comfy with it. There are plenty of ways to make yourself happy along the way (only flying elevator, only turning with rudder, etc), but this is the goal to smooth rollers in any direction... and pretty much regardless of how you start practising, if you keep practising relentlessly, this is where you'll end up.
Also note that this is for flying flat circles... if the plane changes orientation to vertical (like vertical loops and 8's), the control targets remove the "fight gravity" angle to be literally centered in the direction you want to go... but the idea remains the same: if you can change the control target to wherever you want relative to the roll, you can fly a roller in any direction.
>>>Click for the Rolling Harrier Input Tutor<<<
With the Rolling Harrier Input Tutor you'll see that they slow down as you approach the max deflection, and speed up through the center... yes... this is actually how it's meant to be done, it's the *perfect* rolling harrier input motion. Mode One dudes get to simply rotate the right hand stick, this web app separates the two inputs from that circle... which is a sine curve, and then that sets the motion. Most of us flying rollers clunk the sticks over in roughly the right pattern, but if you can get this motion down exactly, then you'll be certainly flying rollers, this shows the proper separation and direction of input for a rolling harrier for Mode Two guys.
SBACH 342 ROLLING HARRIER SLOW MOTION (1 min 13 sec)
TRANSMITTER PROGRAMMING SET-UP AND MIXING TIPS
Michael Wargo kindly sent me these PDF's on the subject enjoy !
Programming and setup
BoneDoc Talks Expo
Ultimately expo is all about preferences. Having said that though, a mid rate would be useful for something like a roller. The slower the roll, the better your chance of timing your input correctly. This is especially more important as you're learning it, or as you're learning new stuff. Essentially, just take it down to get the roll rate you'd want.
For me personally, I usually leave rudder and aileron in high, and flip back and forth between the high/low elevator, depending on whether I'm flying pattern, or 3D. Rudders are generally given a high (70-85%) expo, so you can easily get away with using high rudder all the time. I tend to want my elevators more responsive, so my expo is around 60% or so, which means it's too sensitive for flying pattern / precision. So I set that rate around 35%, with an expo around 30% or so.
General rule for expo: If you're all over the place, then your expo is too low / rate is too high. If you find yourself being "behind the curve", and not correcting enough, then your expo is too low.
FLYING CIRKUS 3D UNIVERSITY SERIES.
3DU Setup & Trim (7 min 51 sec)
3DU KE Spins (3 min 55 sec)
3DU Hovering (3 min 12 sec)
3DU Flat Spins (4 min 26 sec)
3DU Torque Roll (6 min 5 sec)
3DU Snaps (3 min 12 sec)
3DU Rolling Harriers (3 min 31 sec)
-switch rolling harriers
-inverted flat spin
-knife edge spin
-Aussie Toilet Bowl
-Enema, aka Pop Top or Zwimbleturm
-Inverted Pop Top, zwimbleturm, enema
-positive Knife edge spin (with up elevator)
-weeble wobble (Also called a falling leaf)
-Lomcevak (sometimes called a crank shaft)
-rolling figure eight
-rolling vertical figure eight
-knife edge wall
-the other kind of knife edge wall (they're two completely different maneuvers, but I've heard them both called a knife edge wall)
-rolling cuban eight
-knife edge cuban eight
-rolling half and reverse half cuban eight
-knife edge half and reverse half cuban eight
-knife edge loop
-A WT.F !
-Dirty Torque Roll
FLIGHT TRIMMING AEROBATIC PLANE'S Written by Joel AKA TurboParker.
For those who are new to the world of purpose-built aerobatic planes, I decided to post the following information on flight-trimming:
Aside from creating an unflyable condition, CG settings are largely a matter of preference. However, many pilots find that with purpose-built aerobatic ships, adjusting the CG for neutral or near-neutral handling usually works best for all-around aerobatics & precision flight, while a slightly aft CG usually works better for 3D, and a slightly forward CG typically improves stability & tracking - which may be desirable when flying in turbulent air. Understanding the effects of flight-trimming & CG placement, plus experimenting to find the settings that work best for a given airframe and flight condition, will allow the pilot to optimize most any airframe to suit one's purpose and flying style.
The neutral handling point, or CG 'sweet spot' as it is called by some, is the balance point which provides neutral pitch stability. No pitch-change with changes in throttle or airspeed. No pitch change when rolled to knife-edge or when rolled inverted. When balanced at this point, an aerobatic plane simply goes where it's pointed until commanded to do something else. Pattern planes are usually balanced at or slightly forward of the sweet spot. 3D planes are usually balanced at or slightly aft of the sweet spot. The manufacturer's recommended CG range for most trainers & sport planes is typically well-forward of the sweet spot. Assuming that the airframe is straight & true, adjusting the CG in small increments will allow one to tune the plane's behavior.
I will attempt to explain what's going on in non-technical terms.
First off - my comparisons below assume we are talking about a purpose-built aerobatic plane or aerobatic sport-plane with a symmetrical or semi-symmetrical airfoil (not a Cub). One that is properly built - correct thrust-line, wing incidence, tail alignment, etc.
All else being equal, the slightly nose-heavy plane will be less sensitive in pitch & yaw than a neutrally-balanced or slightly tail-heavy plane. The nose-heavy plane will also have to fly faster & land faster to prevent stalling. These two factors are largely responsible for the improved wind penetration vs. the neutrally-balanced or slightly tail-heavy plane. Unfortunately, they are also detrimental to slow-speed flight. The nose-heavy plane will have more drag in level flight at a given airspeed, and will therefore require more power to maintain cruise speed. Additionally, the nose-heavy plane will usually have a lot more throttle/pitch coupling. If it's extremely nose-heavy, the nose will drop dramatically during turns, or when power is reduced. There may not be enough elevator authority to establish a power-off glide. It may also be impossible to flare during a power-off landing. Conversely - when power is applied, the nose-heavy plane will tend to pitch up. During knife-edge, the nose-heavy plane will tend to pull to the canopy, unless down-elevator is used. These things happen because the nose-heavy plane requires a certain amount of up-elevator trim for level flight at a given airspeed.
Compensating for a forward CG with elevator trim causes the plane's behavior to change as the power setting or flight angle changes, because the trim required is dependent on speed and flight angle. For instance, if up-trim is required for level flight, when rolled inverted, the up-trim becomes down-trim, which is the opposite of what is needed, so the plane dives. In KE flight, that up-trim turns into "side-trim" which makes the plane pull towards the canopy. The extra nose-weight is now acting on the yaw axis, and is being compensated with 'top rudder', so the up-elevator trim now pulls the plane toward the canopy. A change in speed will change the effectiveness of the up-trim, which will make the plane pitch up as power is added, and pitch down as power is cut. (Note: most trainers and many sport & scale general aviation planes will also tend to climb/dive when power is added/cut, but in these cases, the behavior is to be expected.)
Most full-scale general aviation planes are balanced somewhat forward of the neutral point for safety/stability. RC trainers & sport-planes are also designed to be very stable, and usually specify a forward CG.
The neutrally-balanced plane will usually have very little (if any) throttle/pitch coupling. The nose will stay put when power is increased/decreased. The nose will not drop much (if at all) during turns. The plane will also stay level in knife-edge - even without rudder (of course, top-rudder will still be required to maintain altitude). Also - there will be little, if any rudder/pitch coupling during knife-edge. Slow-flight will be much improved, and establishing a shallow power-off glide will be much easier - as compared to the same plane in nose-heavy trim. Very short landings are also easier, as there will be plenty of elevator authority to come in a bit nose-high, and then flare at touchdown. Aerobatic maneuvers become much easier, as the neutrally-balanced plane has no tendency to self-recover. Put it into a climb or dive, and it will stay on track until commanded to do something else. The nose will stay put regardless of power setting. When trimmed for level flight, the neutrally-balanced aerobatic plane will fly level inverted with little, if any elevator input, and should fly a knife-edge pass with no tendency to pitch toward the canopy or tuck to the belly.
A plane that is balanced at or very slightly forward of the neutral point will typically be well-suited for precision aerobatics. This is where pattern planes are usually balanced. Purpose-built full-scale aerobatic planes may also be balanced close to the neutral point. For less-experienced RC pilots, the neutrally-balanced plane can be challenging to fly. For instance, the nose doesn't drop as the plane slows down; the plane usually descends in a level attitude, and may stay level after it stalls - or iit may suddenly drop a wing if aileron input is given. Hence, there are typically no visual clues of an impending stall. When put into a dive, the neutrally-balanced plane will not self-recover; it will continue on the path until the pilot gives some stick input. Same is true for climbs.
Note: With flat-plate and symmetrical airfoils, a certain amount of trim is required for level flight because they must fly at a positive angle of attack to generate lift (unlike semi-symmetrical, flat-bottom, or under-cambered airfoils). Therefore, when trimmed for level flight & rolled inverted, they will require a hint of down-elevator for level inverted flight - even though the CG is set at the sweet spot.
The slightly tail-heavy plane will excel in 3D maneuvers - especially harriers, elevators, flat-spins, hovering, tail-slides, and tumbling maneuvers. Precision flying usually suffers due to the effects of negative pitch stability. Pitch-instability will cause the tail-heavy plane to become extremely sensitive to elevator input. Throttle/pitch coupling will also return, but the effects will be reversed as compared to the nose-heavy scenario: When trimmed for level flight, the slightly tail-heavy plane may have a tendency to tuck its nose when power is applied, and will tend to balloon when power is cut. It will also have a tendency to pull to the belly during knife-edge. When trimmed for level flight and then rolled inverted, the tail-heavy plane will usually climb. These things happen because the tail-heavy plane requires a certain amount of down-elevator trim for level flight at a given airspeed.
Compensating for an aft CG with elevator trim causes the plane's behavior to change as the power setting or flight angle changes, because the trim required is dependent on speed and flight angle. For instance, if down-trim is required for level flight, when rolled inverted, the down-trim becomes up-trim, which is the opposite of what is needed, so the plane climbs. In KE flight, that down-trim turns into "side-trim" which makes the plane tuck towards the belly. The extra tail-weight is now acting on the yaw axis, so the down-elevator trim now pulls the plane toward the belly. A change in speed will change the effectiveness of the down-trim, which will make the plane drop the nose when power is added, and pitch up when power is cut.
A bit more tail-heavy, and the plane may become so unstable in pitch that it is impossible to fly. Some airframes are more forgiving than others in this respect. For instance, the UM Sukhoi has a very wide flyable CG range. It will fly with the CG anywhere from 25mm (extremely nose-heavy - very poor flight performance), to 42mm (definitely tail-heavy - wild 3D, but a real handful to fly). Some airframes are not at all forgiving with CG placement. Some may immediately crash after take-off when they're even moderately tail-heavy. Others may remain flyable until they're put into certain situations, such as a spin - and then become completely unrecoverable.
Although full-scale planes are usually designed to be balanced for positive pitch-stability - or in the case of purpose-built aerobatic planes, near-neutral pitch-stability, there are exceptions. Many fly-by-wire fighters and most, if not all of the thrust-vectoring fighters are purposely designed to be aerodynamically unstable so they can do wild, uncoupled flight maneuvers. The flight-control computer(s) sort it all out for the pilot.
Trimming aerobatic RC planes:
It has been said that a nose-heavy model may fly poorly; however a tail-heavy model may fly only once. For the most part, it's true. It's best to start out toward the nose-heavy side of the manufacturer's recommended CG range, and then sneak up on the neutral point.
The main problem with tuning RC airframes for one's desired flight characteristics is that many of the adjustments are interactive, and some parameters have similar symptoms when they're out of adjustment. Things must be checked/adjusted in the proper order - otherwise the process can become quite frustrating. The guide below will allow the pilot to sort out various handling issues in a scientific manner. Courtesy of the NSRCA (National Society of Radio Controlled Aerobatics):
See the attachment for a printable version.
Remember - the guide above is intended to be used for flight-trimming purpose-built aerobatic planes, or at least aerobatic sport-planes. It is not intended to be used for trimming scale general-aviation planes like Piper Cubs & such, warbirds, RC trainers. These aircraft are usually designed to have at least some positive pitch-stability. For instance, one would not expect neutral behavior from a J-3 Cub. The experience of flying a tail-heavy warbird is not something you really want to have. That said, the general flight-trimming rules still apply. For instance, a nose-heavy GA plane or warbird will drop the nose excessively in turns or when power is cut, and it may lack the elevator authority to execute a power-off flare.
Good luck, be safe, and happy flying!
CG A QUICK SET-UP GUIDE
To some extent it is true that each pilot will prefer the CG slightly different but in reality the "right" CG range for 99% of people with be within a very small range. From just aft of neutral to just ahead of neutral.
Here an older post about how to balance a plane in the air.
1. First thing you need to do is take the elevator trim steps down to about 25% of their original value in your radio. In JR/Spektrum that means moving your trim steps on from 4 to 1. That makes each click of trim a smaller movement and makes exact trimming easier. Also, check the centering of each servo and each linkage for slop.
2. You need to balance it in the position indicated in the manual using a CG machine or finely calibrated finger tips. In the middle of the CG range.
3. Trim it in flight to fly straight and level upright at half throttle. Or at a pace similar to what you will be flying most of the time.
4. At the exact same speed/power setting as in step 3. Roll it inverted and see what it does. If it climbs then it is tail heavy. If it dives to ground then it is nose heavy.
5. Adjust the battery as necessary so that at half throttle (or your desired flying pace) it is trimmed and flies straight and level upright AND inverted. NOW, even if you have an incidence and thrust line issue, as long as you use the same throttle setting/ airspeed you will be able to get this far with no problem.
6. Climb as high as you can see the plane. Kill the throttle, level off and let the plane slow down to near stall speed. Point the nose straight down (perfectly perpendicular to the ground) and let the plane accelerate with the power off and your hands completely off the sticks.
If it goes straight as an arrow all the way until you have to bail out, then your CG and incidence are fine.
If it does one thing, then straight, then another thing, you have an incidence issue. (i.e. pull,straight,dive - pull,straight,pull - dive,pull,straight, dive,straight,dive or even pull,straight,pull - you get the idea.. things change with airspeed etc...)
If it pulls or pushes the same way and amount the whole time you might still have a CG issue but you also probably have a thrust line issue.
7. If it pulls or pushes the same way and amount the whole time go back to testing the upright and inverted flight trim. At half throttle does it still fly the same upright and inverted? At 1/4 throttle does it dive, climb or stay the same? At 3/4 throttle does it dive, climb or stay the same? If it does different things at different throttle settings and has a symmetrical airfoil you either have a CG issue or thrust line issue but if you do the above test both upright and inverted and the plane either moves to the ground or to the sky in both conditions then it is likely still a CG issue. Conversely, if the plane does different tendencies upright than it does inverted at different throttle settings then it is likely a thrust issue.
For example: If the plane is good upright and inverted at 50% throttle but I then try both again at 25% throttle and it dives to ground on both sides it is likely CG. But if a different plane is good upright and inverted at 50% throttle and then I try both at 25% and it dives on one side and climbs on the other then it is thrust line.
Click for Initial Safe Center of Gravity (ISCG) Fore and Aft Balance
Click CG Calculator
Click for How to Become an Awesome Pilot
Click for 3D with Blaine
|Dec 12, 2012, 05:42 AM|
|Jan 12, 2014, 02:53 PM|
Joined Dec 2013
Great stuff Kris, i have a wish to know exactly what a funnel hover is? I think in your list it is an Aussie toilet bowl. I am not sure what it is, i mean, does the plane lean with the engine into the centre of the bowl, or lean out to wards the outer rim of the bowl?
Can anybody point me to any videos showing this maneuver?
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