Flight school is back with another advanced topic today, designed to help Scramble pilots master their skills and excel in dogfighting. Watch the video and read Jon’s notes below to prepare for your next match.
Dogfighting with Energy Management
Hi pilots, I have another heavy physics lesson for you today; our topic is Energy Management. There are whole schools devoted to the study and development of dogfighting tactics, and the learned among you will surely have forgotten more about aerial combat maneuvering (ACM) and basic fighter maneuvers (BFM) than I will ever know, but since all these theories rest on the principles of energy management, I hope that a thorough investigation of its physics foundation will be of benefit to a wide audience of Scramble players.
Godspeed,
Jon
Airspeed and Aerodynamic Control
Since the middle of the First World War, fighter aircraft have employed guns fixed to their airframes, and a pilot must orient their entire aircraft to bring these guns to bear on a target. Aircraft generally orient themselves through aerodynamic control – the manipulation of the surfaces or shape of a body as air moves around it to inspire forces and moments to act on that body. We define the rate and quality of this air moving around a body as “airspeed” and, regardless of the aerodynamic design of an aircraft or the qualities of the air moving around it, the laws of physics demand that some energy be transferred between aircraft and air, that the energy differential between them be lessened, and thus that every instance of aerodynamic control and every resulting maneuver incur a cost in energy that is mostly paid through airspeed.
Fighter Energy Stores
The energy of movement for fighter aircraft is concentrated into three major stores:
- Kinetic energy is the energy of a mass moving through space – it is the energy of speed – and it is proportional to the square of the velocity of this mass. Airplanes can exchange kinetic energy with the air through which they move to adjust their orientation, as mentioned above, and they can also convert kinetic energy into potential energy by increasing their altitude (climbing).
- Gravitational potential energy is the energy stored by a mass at some height above the surface of the earth – it is the energy of altitude. An aircraft that climbs through the sky can be thought of as banking some energy as altitude, and this energy will eventually be converted to kinetic energy as airspeed when gravity accelerates the aircraft back toward the surface of the earth.
- Chemical potential energy is stored in fuel, and it may be converted to kinetic energy by an engine through combustion and the driving of a propeller through air to create a thrust force.
In general terms, the conversion of fuel into airspeed is a slow process, while the conversion of altitude into airspeed is a fast process; an aircraft accelerated by its engine and propeller may take over a minute to achieve a speed of three hundred miles per hour, while an aircraft diving from high altitude can achieve the same change in airspeed in as little as ten seconds.
Scramble dogfights happen two and a half seconds at a time, and even the longest Scramble matches (the record at the time of publishing sits at 140 turns) start and finish on a time scale that is fairly trivial for the conversion of fuel (chemical potential energy) into altitude (gravitational potential energy). Scramble players will find it difficult throughout the course of a match to regain airspeed purely through level flight and full throttle; there just isn’t enough time to meaningfully climb.
Spending Energy
Dogfights in Scramble, as in real life, may wind and loop, but they will eventually descend from their starting altitude to one nearer the sea, and this descent is emblematic of the spending of airspeed energy on aerodynamic control and the transfer of banked altitude energy to restore airspeed.
Since altitude banked at the beginning of a dogfight is functionally a finite resource, pilots should be careful to spend energy on offensive or defensive maneuvers that shift the dogfighting advantage in their favor. Most offensive and defensive maneuvering falls into the categories of either pointing your nose at a target, or preventing your target from pointing their nose at you. And most costly maneuvering involves either pulling hard on the control axes (spending airspeed) or cutting throttle (reducing energy added via fuel burn).
Some common examples of costly maneuvers are:
- Pulling hard to line up a shot on an enemy
- Aggressively maintaining position on the tail of an enemy
- Pulling hard to spoil a enemy’s shot on your aircraft
- Aggressive maneuvering to slow down and cause an enemy to overshoot
- Cutting throttle to slow down and case an enemy to overshoot
- Cutting throttle to avoid overshooting an enemy
Drag and Efficiency
Every aerodynamic maneuver has an airspeed cost, but some maneuvers are more efficient than others. Drag, the aerodynamic force opposing an aircraft as it travels through the air, is the force that determines this cost in airspeed. Drag generally increases as pilots command harder pitch, yaw, and roll control inputs, but drag is proportional to the square of velocity and thus it increases dramatically for aircraft maneuvering at high airspeeds.
Every aircraft type in Scramble has a unique aerodynamics definition and thus every aircraft has a unique performance envelope that varies according to airspeed, control inputs, throttle, damage, and more parameters. Some aircraft will perform high-G turns more efficiently than others at a particular airspeed, and some aircraft will be able to pull a higher pitch angle before incurring massive drag penalty than others, but players will generally notice drag increasing substantially, for all aircraft, at pitch inputs beyond eighty five percent. Players hoping to fight efficiently should be careful to keep from sustaining aggressive pitch or yaw maneuvers for multiple turns in a row.
Analyzing Energy and Tactics
Scramble is a dogfighting game, but it is also an analysis tool. This makes Scramble distinct among dogfighting games, where the state-of-the-art is to analyze your performance after the match, and often outside of the game engine itself by importing flight tracks into standalone analysis software.
Scramble draws 3D ribbons in world-space to represent both the predicted flight paths of airplanes and the historical paths aircraft flew during previous turns. The flight ribbons of Scramble are the game’s most iconic imagery, and they are also the first read of flight dynamics and gameplay mechanics for most players; it is natural to expect control inputs to resolve themselves in the sky, so we attempt to render major warnings and aircraft states alongside the flight ribbons:
- Aircraft in a low speed state will render a ribbon with inverted white chevrons.
- Aircraft projected to stall will render a ribbon with connected red warning chevrons
- High-G maneuvers render ribbons with dashed black lines to indicate airframe and pilot stress
- Predicted firing solutions render ribbons with orange markers resembling the firing aid reticles
- Unconscious pilots render ribbons with solid black lines
- Damage, failure, and debris events all render as positional markers in 3D space
We have spent a lot of resources designing the HUD UI of Scramble to make players aware of the energy states of their airplanes. The Scramble HUD is inspired by dial gauges typical of aircraft instrumentation, but rather than rendering linear airspeed and altitude the Scramble HUD renders airspeed energy and altitude energy on symmetrical scales, so players can watch energy trade between airspeed and altitude live as airplanes climb or dive. These energy dials are scaled so that one full dial of altitude energy corresponds to roughly 350 mph of speed energy - quite fast for an airplane. Every fill of the altitude gauge is banked as a discrete dot while the fill itself resets, so each dot also corresponds to roughly one fully exhausted airspeed gauge of maneuvering. Scramble displays energy gauges on the HUD for both selected friendly aircraft and targeted enemy aircraft, so players can quickly distinguish the total energy states of friends and foes.
In addition to art and iconography for analysis, Scramble invites players to review the action of previous turns, or of the whole match, at any point during play. Players can scrub unbroken or frame-by-frame through the maneuvers of every aircraft, and all 2D and 3D UI will dynamically update to reflect the currently rendered simulation frame. The turn-based nature of Scramble allows players to pause and reflect on the tactics being employed against them, and the review phase paired with free camera or the tactical view should help players discern details and vulnerabilities that only the most thoroughly trained pilots can interpret in a real-time dogfight.
https://store.steampowered.com/app/1530450/Scramble_Battle_of_Britain/