Aerobatics

What Is Aerobatics?

Aerobatics is a judged sport before it is a flight sim. Five figures run in order: a loop, a roll, an immelmann, a stall turn and a split-S. Each names a stick direction, an airspeed and a length of hold, and the judge pays from a maximum of 220 for the roll to 340 for the immelmann.

The aeroplane opens at 5,500 feet and 190 knots, and it loses 170 feet a second from that moment on. No stick position changes that. The stick decides where the energy sits: pulled back, it climbs while the airspeed falls away; pushed forward, it dives to buy airspeed back. The exchange runs at 22.2 feet of height per knot.

The display ends when the fifth figure is judged, or when the altimeter reaches zero. The first is what you are flying for.

Reading the Brief

What each line of the brief tells you, and the one rule that never changes.

The figure

A name and a stick direction. Three of the five want the stick back, two want it forward, and the wrong one scores nothing.

The entry speed

The airspeed the judge wants when the stick goes back. Ten knots either side is forgiven outright; past that the award falls away in a straight line to a zero at 45 knots.

The hold

How long the stick stays over. Three tenths of a second either way is free, and a second and a half out stops the figure and scores it nothing.

The base award

What the figure pays flown perfectly, from 220 for the roll to 340 for the immelmann. Entry and hold multiply it, so half right pays about half.

The roof

The box stops at 8,000 feet. A figure still being flown when the aeroplane crosses that line scores nothing, however good the entry was.

How to Play

1. Press the button and the aeroplane is at 5,500 feet doing 190 knots, loop armed.
2. Read the brief before you touch the stick: the figure, the stick it wants, the entry speed and the hold.
3. Check the speed tape along the bottom. The band marks the entry speed, green within ten knots of it and red at forty-five.
4. Push the stick forward to dive. Two seconds of that buys 27 knots and costs 953 feet, which is a real trade against a clock.
5. Pull back to climb and slow down. A two-second pull is worth 240 feet and 26 knots.
6. Hold the stick for the length on the brief, then let go. The judge reads the airspeed at the stick, the hold, and whether the aeroplane left the box.
7. Fly all five. The display ends when the last one is judged.

Why the Stick Is the Whole Game

Every figure is an energy problem wearing a name. The loop wants 195 knots and the aeroplane starts at 190, which is five knots, or 111 feet of height at 22.2 feet a knot. The immelmann wants 230, forty knots and 888 feet. The stall turn wants 135, so 55 knots have to go, which is 1,221 feet of climbing to get rid of them.

The stick moves energy between two tanks that lose 170 feet a second whatever you do, so the display is one budget of 5,500 feet.

A back stick only climbs while the aeroplane is above its 55-knot stall, and the climb it buys falls away with the airspeed. At 195 knots a full pull is worth 166 feet a second. At 120 knots the same pull is worth minus 14. By the stall it is worth nothing, and you sink at the usual 170 with the stick doing nothing.

Ending on the ground is no surprise that crept up on anybody. It is 5,500 feet at 170 feet a second, which is 32.4 seconds.

What the Judge Is Looking For

Three things, measured separately. The entry comes first: the airspeed when the stick goes back, against the number on the brief. Ten knots out pays in full. Twenty out pays 214 of the loop’s 300, thirty out pays 129, and forty-five out pays nothing.

The second is the hold, clocked from the stick going back to the stick coming off. Three tenths either way is free. Eight tenths long is about half the figure, so a loop held for 3.9 seconds instead of 3.0 pays 153.

The third is the box. The roof sits at 8,000 feet, 2,500 above where the display opens, so a fast pull finds it quickly. Start the loop at 7,900 feet and the roof arrives 0.66 seconds later and the figure pays nothing.

Underneath all three runs a clock: two points a second for every second inside the box, paid whether or not a figure is in progress and stopped above the roof. A clean sequence comes to 1,420 in awards and about 30 of box time.

The Sequence, Figure by Figure

The order is where the difficulty lives. The loop opens at 195 knots with the aeroplane already doing 190, and it carries the longest hold: three seconds of back stick finishes 38.9 knots slower.

The roll is the shortest figure at 1.4 seconds and wants 170 knots, so it needs speed shed rather than found. Two of the five want the stick forward, and both are dives, which is where the height the loop spent comes back.

The immelmann carries the biggest award at 340 and the least room for error. It wants 230 knots, the fastest entry on the brief, and holds the stick back for 2.6 seconds. A fast aeroplane and a long pull is the shortest route to the roof.

The stall turn wants 135 knots, 55 below where the display started, so the height has to be found before the figure can be attempted. Five seconds of back stick takes 190 knots down to 135 and leaves the aeroplane 396 feet higher.

The split-S closes from 115 knots and dives away what the stall turn climbed for, and the display ends wherever the aeroplane happens to be.

Aerobatics on a Phone

Two hold buttons at the bottom of the screen, where a thumb already is.

Hold a button down for as long as you want the stick held, and let go when the hold is finished. The judge measures that hold to a tenth of a second, so a latched button would turn every figure into a guess.

The stage is laid out to be read at arm’s length. The brief runs down the left with the live figure lit, the banner names its three numbers, and the speed tape along the bottom shows the airspeed against the band the judge wants.

A phone display is the same display, and not by approximation. The model does not scale with screen size, so 5,500 feet, 170 feet a second and a 195-knot loop mean the same thing on a phone as on a desktop.