I hear the term "Pattern" mentions quite often in RC flying (there is a forum for it isn't there?). What is it? Is it like aerobatic flying or something?

"Pattern flying" is pretty much what the name says. It is precision flying of a preset sequence of aerobatic maneuvers with a prescribed area (the box). Usually the scoring starts out assuming a PERFECT score and you are charged for each deviation from "perfect".
The system is described fairly well here:
http://www.geistware.com/rcmodeling/...ics/aresti.htm

Pattern flying is a competitive sport in the RC hobby.

There are 5 levels. Sportsman, Intermediate, Advanced, Masters and FAI. Each is progressively more difficult and requires more skill.

The pattern for each level is a defined sequence of maneuvers. There are several maneuvers that are performed on "center" directly in front of you and there is a turnaround maneuver at each end of "the box".

In Pattern the box looks like this.
Wherever you are standing there will be painted or chalked lines extending out in a V from your feet at 60 degree angles to your left and right. These lines are usually visible for about 150' but they extend infinitely so the farther out you fly, the larger the box gets. But you are limited to how far away you can fly, most people fly about 150-150 meters out in front of them. This provides a long enough box to give you time to setup to perform each maneuver. As with a V the further away from the apex you get the wider the space gets.

Judging is based on several things, I will tell you the basics. Theres more to it but this will get you started.


Radius- All of them must be the same within a maneuver, so if you are doing a square loop,, all 4 corner radii must be the same.
Center- The center of the maneuver must be at the center of the box. (Standing facing directly forward, Hold your antenna up in front of you, thats pretty much a refernce point for the center of the box.
Lines- All lines within a maneuver must be of equal length as appropriate for the geometry of the maneuver. So a square will have all lines the same length, but a diamond 8 wont. Draw two diamonds on top of one another and you will see what I mean.
Roll Rate- All roll rates must me equal rate within a manuever ( and if you are REAL good they will be the same throughout the pattern)
They must also be centered on the line you are rolling on.
Takeoff and landing must be on the runway and you should touchdown within 50 meters of the center.. Or you get scored a zero.

Heres the sportsman pattern. You can find out all you want ot know at www.nsrca.org


Sportsman 4011

1. Takeoff (U)
K=1


ENTER THE BOX(must call out audibly to enter)


2 Straight Flight Out (U)
K=1

3 Half Reverse Cuban Eight (Turnaround)
K=1

4 Straight Flight Back (D)
K=1

5 Half Cuban Eight (turnaround)
K=1

6
Two (2) Inside Loops (U)
K=2


EXIT THE BOX(must call out audibly to exit)

(free turnaround to get setup)

ENTER THE BOX(must call out audibly to enter)


7 Two Point Roll (D)
K=2

8 Stall Turn (turnaround)
K=2

9 Cobra without Rolls (U)
K=1

10 Immelmann Turn (Turnaround)
K=2

11
One Horizontal Roll (D)
K=1

12 Split "S" (Turnaround)
K=1

13 Double Immelmann without Rolls (U)
K=2


EXIT THE BOX (must call out audibly to exit)


14
Landing
K=1


TOTAL
K=19




Note: (U) means upwind; (D) means downwind.

Description of new maneuvers

Two Point Roll Model performs one-half (½) roll to level, inverted flight, pauses, then performs another one-half (½) roll in the same direction to level, upright flight. Center of maneuver is middle of inverted hesitation. Length of inverted hesitation is not a reason for downgrade as long as it exists. Downgrades:

1. Model does not hesitate at inverted.
2. Roll rate not constant.
3. Over or under rotation of rolls, One Point per 15 Degree Rule.
4. Changes in altitude.
5. Changes in heading
6. Roll rates not constant.

Cobra Without Rolls Model pulls to a 45°climb, pauses, pushes to a 45° dive, pauses, then pulls to recover in level flight at the same altitude as entry. Center of maneuver is middle of 90° push. Downgrades:

1. Climb and dive not 45°
2. Loop segments not round with same size and radius
3. Changes in heading
4. Exit not same altitude and heading as entry

Double Immelmann without Rolls Model pulls through one-half loop to level, inverted flight, hesitates, then pulls through a second one-half loop to level, upright flight at the same altitude as entry. The horizontal leg should be equal to the diameter of the half loops. Downgrades:

1. Half loops not round with same size and radius
2. Changes in heading
3. Exit not same altitude and heading as entry

What Bruce and Mike have said is dead on the money.

Ken

And then there is the other "pattern": a race track pattern that everybody is supposed to be flying at the field when there are lots of planes in the air and you want to minimize the possibility of midairs... pretty boring but I guess there are reasons.

This is usually called "flying the (landing) pattern" as opposed to "(competition) pattern flying". In either case you are flying a manuever sequence in a predetermined manner/order.