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Apr 10, 2005, 10:15 AM
Registered User
matchlessaero's Avatar
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3D Definitions and info for the Beginner

No discussion in this thread please. If you have a definition to add, please do so clearly and to the point(easy to understand) If you have a correction, please PM it to the original author and let them fix it.

Here is a list of 3D Aerobatic definitions. I am hoping we can create this list as a great place for newbies and old guard 3D'rs to go to learn the vocabulary of this aspect of RC Flying. Thanks to TeamSME for suggesting this.

Flight Definitions-
Hover- Flight realm in which the airplane is totally and entirely supported in the air by thrust from the propeller.
Torque Roll- When an airplane spins on its longitudinal axis while hovering. True torque rolls are totally induced and sustained by the torque from the propeller. Aileron is not involved.
Harrier (and inverted Harrier)-Flight realm when the airplane is partially supported with lift from the wings, and partially supported with lift from the propeller. Airplane is generally flying at a high angle of attack with the nose up.
Knife Edge Flight-Flight realm where the airplane flies supported by lift generated by the fuselage and the rudder. Wings are generally in a vertical position.
High Alpha Knife Edge-Flight realm where the airplane flies totally supported by the fuselage/rudder and the propeller. Wings are generally in a vertical position. Airplane generally flies at a high angle of attack with the nose high.
Rolling Harrier-A Rolling maneuver in which the airplane remains at a high angle of attack while performing an aileron roll. It is essentially made up of a sequence of: Upright harrier-High Alpha Knife Edge-Inverted Harrier-High Alpha Knife Edge-Upright Harrier-repeat

Airframe/Powerplant definitions-
Full Fuselage-An airplane which has a 3 dimensional fuselage
Profile- An airplane which has a 2 dimensional fuselage, usually the shape when viewed from the side resembles an aircraft (sometimes something else..)
Shockie- Originally proliferated by the popular ShockFlyer series of aircraft, this type of airplane uses a profile fuselage which is strengthened by another profile of the fuselage when viewed from the vertical. The resulting fuselage looks like a + sign when viewed from the nose or tail.
VPP- Variable Pitch Prop, a propeller which has the ability to convert from positive pitch to negative pitch and back in flight. This allows the airplane to move in reverse.
Wobbly Adapter-A flexible method of mounting the propeller to the propshaft of a motor. Many commercial and homemade versions of this, but they all tend to use rubberbands or O-rings wrapped around the propeller and connected to the propshaft to allow the propeller to flex or 'wobble' on the propshaft in 'unintentional landings'
Thrust to Weight-A ratio reached by dividing the amount of thrust a power system is capable of delivering by the weight of the ready to fly airplane. 3D airplanes require more than 1 to 1, and 2 to 1 is usually the goal.

Building Materials/Construction-
FFF- FanFold Foam, insulating foam found in home improvement and construction stores. Generally available in a thin 1/4 or 3/8" thickness, blue or pink in color (more information in the foamy area of RCGroups)
Depron- Thin foam with a light skin attached. Available in many thicknesses from several vendors. Usually available in Grey or White and varying thicknesses from 2mm up to 6mm.

Ya'll add some more!
Last edited by matchlessaero; Apr 11, 2005 at 08:14 PM.
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Apr 10, 2005, 02:45 PM
Sussex, UK
RobinBennett's Avatar
There will probably be some disagreement over the exact definition of this one, but I had to read the forum for days to work what you lot were talking about:

3D aerobatics or what this forum is all about
Controlled flight where the wing is stalled, or stalled a lot of the time. It doesn't necessarily involve a lot of vertical movement (as the name suggests) or imply that normal aerobatics doesn't involve flying vertically.
Sometimes summarised as 'stuff that ordinary aeroplanes can't do!'
Apr 10, 2005, 03:20 PM
ExtremeFlight - 3DHS - Legacy
blucor basher's Avatar
Coupling - Coupling is a condition where an airplane not only responds to the control input you give (i.e., when you give right rudder it turns right) but does other things as well (i.e. when you give right rudder it turns right, noses down, and rolls left.).

Coupling is common in 3D aircraft, and is often a fact of life, although designers try to minimize it. Coupling can make certain 3D aircraft difficult to fly precisely or to learn 3D on.

To control coupling, one solution is to use a "computer radio", that is, a transmitter which allows you to mix controls together. If you have an airplane which has pitch coupling on the rudder (i.e., it pitches up or down when you apply rudder to turn) many computer radios allow you to mix in some elevator control with your rudder to counteract the coupling.

Also, on many designs, coupling can be minimized by using a different Center of Gravity location, either forward or back, or up or down. This is usually accomplished by moving the mounting location for the battery pack.
Apr 10, 2005, 03:30 PM
ExtremeFlight - 3DHS - Legacy
blucor basher's Avatar
Brushless - A type of electric motor with very few moving parts and usually high performace. Most 3D aircraft use brushless motors, although some beginner's type 3D planes come with standard "brushed" motors which have less power and durability.

Brushless motors require specific brushless electronic speed controllers to operate them. Brushless speed controllers are marked as brushless on their packages and can also be identified by Three (3) wires to connect them to the motor. Brushed-type speed controllers typically are connected to their motors by Two (2) wires.

Brushless motors typically can spin in either direction, and so if you hook one up and determine that your propellor is spinning backwards, you may correct this by switching any two of the three wires connecting the motor to the controller.

Outrunner - An outrunner is a specific kind of brushless motor with the magnets arranged at the outer rim of the motor (the magets run outside the wire coils, hence the name). This type of design typically gives high torque, and so many outrunners can swing large propellors (often used in 3D flying) without gear reduction boxes. This gives a very simple and durable setup.
Apr 10, 2005, 03:40 PM
ExtremeFlight - 3DHS - Legacy
blucor basher's Avatar
Hovering, How To - One of the most impressive 3D tricks is the hover, where the airplane remains motionless, hovering like a helicopter.

In order to hover, an airplane must have at least a 1:1 thrust to weight ratio. However, practically, you need some excess thrust in order to properly control your hover.

Hovering requires control over all three axes of movement. That means ailerons for roll, Elevator for pitch, and rudder for yaw. If your airplane lacks either ailerons or rudder, it will be impossible or nearly impossible to hover. In addition, all of your controls need to be very effective, with large surfaces and large control throws.

Prop selection can be important in hovering. Typically, airplanes use large diameter props with low pitch to hover well. Props are labeled according to their diameter and pitch on the proplr itself and on the packaging. A typical prop may be labeled "1080". This is a 10" diameter prop with 8 inches of pitch. Another could be "1047", this is 10" diameter with 4.7 inches of pitch.
Hovering props typically have low pitch numbers between 3 and 7.

To try hovering, fly your airplane high enough to allow room to correct for mistakes, and pull up into a vertical climb. Reduce throttle until the plane is no longer climbing. At this point, you will have to keep the airplane straight using your controls. It is not easy. Experiment with Exponential if your transmitter has this feature, this may help you to hover easier.
Apr 10, 2005, 03:50 PM
ExtremeFlight - 3DHS - Legacy
blucor basher's Avatar
Exponential or Expo - Exponential control is a feature found on many tramsmitters today. It is very helpful for flying 3D. 3D planes typically have large control surfaces and lots of control surface throw to give them the ability to maneuver well at low speeds and do extreme aerobatics.
However, these large throws and surfaces make these planes difficult to control precisely at high speeds. Often, a pilot has "too much control" when flying faster. This can make your flight "jerky", lacking smoothness.

Exponential control can help this. It is a parameter on many transmitters which causes a given control surface to move very little as the control stick moves in the area around "neutral" or "center" and then as the pilot pushes the stick farther to maximum, the control surface "catches up" so that at maximum stick movement, the control surface has maximum throw.

This is easier to demonstrate then explain. On Futaba or Hitec transmitters, set your controls to "negative exponent" (- exp) to try this effect for yourself. On JR transmitters, set your controls to "positive exponent" (+ exp) to try this effect. These companies simply chose to use the + and - signs opposite from each other.

The amount of expo can be selected, from 0 to 100%, on these transmitters.
Typically, 3D planes can benefit from 40-70% expo on all surfaces, but you must experiment to see what feels best to you.
Apr 10, 2005, 04:01 PM
40%, 5% whats the diff?
TeamSME's Avatar
Prop Braking- A force that slows the plane down on downlines, very helpful when doing parachutes or other downline aerobatics

Downline - When you are flying directly vertical to the ground, usually for a parachute or spin.

3D Propeller A prop that usually has a large diameter and a small pitch. Pitch is the measurement of how far the plane moves per revolution of the prop. It the pitch is 5 it pulls the plane 5 inches. Lower pitch numbers usually put out more thrust and less horizontal speed, vice versa for high pitch
Apr 10, 2005, 08:47 PM
Tee Sqaured
Thomas Manson's Avatar
Flapperon Mixing : A special mix in which, when you pull back on the elevator stick, both ailerons droop down, therefore enhancing pitch control.

CF : a shorter term for Carbon fiber, which is very popular when building small lightweight 3D models.

Freestyle rotines : 3D aerobatics flown in sync with Music.
Apr 11, 2005, 08:52 PM
Texas Ranger
Neil Walker's Avatar
"Cross" or Opposite Aileron: A term describing an aileron input which is opposite to that of the rudder. Used in descriptions of where to move the sticks for maneuvers which can be done in either direction (left or right). For example, instead of saying "full left rudder and a little right aileron", one would say "full rudder and a little cross aileron". This allows maneuvers to be described in a more generic way.
Apr 12, 2005, 11:08 AM
Fixed Wing Fanatic
Jim Walker's Avatar

Flying an axial rolling downline and then applying full rudder, then full down elevator, and finally adjusting aileron and throttle to achieve an inverted flat spin. The inputs are done in that order and in rapid succession.
Sep 20, 2005, 03:01 AM
osmium_192's Avatar
the "cross aileron" is known as the slideslip in full size aircraft which is used to reduce the effective lift of the wings and to increase drag by increasing the frontal area of the fuselage to descend and to bleed off speed usually on mid to late finals approach before landing. In 3D applications when flown at about 40* to horizontal creates an interesting visual appearance and is used more as a way of setting up for a reverse roll turn where in a right turn the aircraft rolls left and right rudder and down elevator is used.
Sep 20, 2005, 04:13 AM
Registered User
Skunkerama's Avatar
Binned it, Re-Kitted it, Pulped it, Splatted.

Terms that can be used when 3D suddenly goes 1D, don't lose hope you'll manage it one day.


Abbreviation of Simulation. Radio Control Model Flight Simulators are widely available now. They are an excellent aid to learning how to get the basics of a maneuver working. They will not teach you how to fly perfectly but they will help. Look at the Simulator forum for advice.

Cyanoacrylate = Superglue. An essential part of any 3D pilots toolbox, some need more than others.
Sep 25, 2005, 04:30 PM
Admin Deluxe
Jim T. Graham's Avatar
"Field Grass Inspector"
This term is derived from the motorcycle term "ashphault inspector". If your plane becomes a "Field Grass Inspector" you will have "heal" it and hope Bro Paul Swany is somewhere in the state.
Mar 12, 2007, 10:44 AM
Choppa Nutta's Avatar
Excessive verbiage.

Erm Was hoping to find a definitive list on moves and stunts that are already established, and theres lots, and the right technique to do them properly.
nice as all this definition is, flying technique is what we want to really master

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