Model aircraft aerobatics. Loops, Cuban Eights, Bunts etc

There's a myriad of aerobatic gyrations that a model aircraft can perform, this section introduces some of the basic aerobatic manouvers.

The Spin I will start with this one as it must be amongst the easiest manouvers to perform (most of us model aircraft pilots have done one of these without even wanting to!) It's important to be comfortable with the spin or else it can spoil your whole day.
When a model aircraft is in a fully developed spin the wing is stalled and no longer flying. This causes a lack of response to the controls. To enter the manouver the model is slowed to stalling point, full rudder then being applied while the elevator control is held back. The aircraft should then be yawing fast in the direction of rudder deflection while slipping vertically downwards at quite a pace. Some model aircraft especially good trainers will recover simply by releasing the controls to neutral, most aircraft need coaxing out of the spin however. This is done by pushing down on the elevator thereby turning some of that vertical slip into forward motion. Next rudder is applied in the opposite direction of spin and recoverer should result within three gyrations with most models. The rudder is returned to neutral when the yawing stops to prevent spinning the other way and the elevator is gently pulled back for full recovery to level flight. In common with some fullsize aircraft a few models will actually begin to spin faster momentarily when recovery is started. This can be disconserting as it appears you are doing the wrong thing with the controls.

TIP Beware the spiral dive. This is what some model aircraft do when asked to spin, and it can pull the wings of some models. When in a spiral dive the aircaft's nose is pointed lower than in a spin and the flight path is that of a corkscrew downwards.

The inside Loop This is the most straightforward manouver to put an aircraft through. Done right it consists purely of pitching. A perfectly round loop however is not quite so easy, the reason being gravity trying to slow the model up in the first half of the loop, and speed it up on the 'downhill' bit. With a powered model aircraft extra power is applied to compensate in the first half while the throttle is closed as necessary as the model moves over the top. The propellor if quite large can actually act as an airbrake like this. The other complication is the wind. This of course effects everything an aircraft ever does. In the case of a loop the effects of wind vary depending on the heading of the aircraft with relation to wind direction. Loops are generally performed directly inline with wind direction. If entering the manouver into wind then the model will be pushed back from where it came from as it performs the loop. This will give a kind of oval shape to the manouver unless you fly it around the loop altering pitch and throttle as necessary to bring the exit point at the same position as the entry point. In the case of a downwind loop you will get the opposite effect.
When looping across the wind, matters are a lot more difficult if you want a smart manouver. The aircraft will be moving sideways downwind in relation to you and the ground, to stop this you have to point the nose of the model into wind throughout the manouver which is more difficult than it sounds. Just pulling up on the elevator will cause what appears from the ground to be a corksrewing loop with the model aircraft moving downwind.

TIP Think of the model as flying in a box of air, this box moving in the direction of the wind.

The outside Loop or 'bunt' This is a negative G manouver. Some models will bunt just as well as they do inside loops, while other model aircraft such as the Junior 60 cannot be made to outside loop at all but will do inside loops with ease. Most of the above info about inside loops is equally relevent to outside loops. Your average trainer if reasonably well powered will outside loop, but make sure you start high up. Alternatively you can roll the model inverted then do your outside loop (be prepared to get called a chicken by fellow modellers if you do this!).