Aircraft construction is one of the more difficult achievements in Besiege. It is, however, a mostly solved problem by now, and this guide will walk you through the important points.
General Aerodynamics[]
Propulsion[]
Frankly, one of the most important things in the plane. In Besiege planes are usually powered by propeller engines, Flying Blocks, Steam Cannons, or Nives. Unlike propellers and flying blocks, water cannons are not flammable. Nives, flying blocks and steam cannons with the NoBounds mod active can provide any amount of thrust.
Variable throttle can be imitated with a set of propulsion blocks on steering hinges which rotation changes the resultant thrust vector.
Propeller Engines[]
Single engine airplanes (or with uneven amounts of engines) require a way to balance out the counter rotation of the main powered block. Any powered rotating block rotating in one direction will turn the rest of the airplane. To counter this effect real planes use trimming. Fortunately, in Besiege we can do this in a simpler manner. One of the ways is to place the engine on a freely rotating block (e.g. unpowered wheel or swivel joint) and attach a mass to it, ideally braces as they have a notably high angular drag, meaning braces will resist rotational movement more than compared to other blocks with the same mass.
The number of aerodynamic blocks connected to the engine will mainly affect torque, but also the overall agility of the airplane. More propeller blocks will increase torque at a slight expense of speed due to the added drag.
The angle at which the aerodynamic blocks are connected orthogonally to the direction of the flight influences the proportion of resulting speed over torque of the engine. Smaller angles (parallel to the flight direction) allow to achieve higher top speeds but have less torque. Higher angles (perpendicular to the direction of flight) reach higher torque but cause more drag and for this reason they have a lower top speed. The amount of torque will mainly affect acceleration and rate of climb of the airplane. Suggested in most cases are angled at around 30° - 45° (where 0° is parallel to the flight direction) as the resulting maximum speed far outweighs the small loss of torque.
Thrust Vectoring[]
Thrust vectoring is changing the angle of the thrust, which allows better control over the aircraft; and unlike control surfaces, it works even at lower speeds. Also might be used to gain STOL (Short takeoff and landing) and VTOL (Vertical takeoff and landing) abilities. Performed by controlling the angle of the jet’s nozzles, or in Besiege, plane’s propulsion blocks with any RTC mechanism.
Building with CoL[]
When adding the first propellers to the plane and its control surfaces, make sure the CoL is around CoM and keep adding them until enough lift is generated. Keep checking that:
- The plane is properly trimmed and there is no spontaneous yawning caused by intersections or roll caused by the engines.
- The plane is sufficiently unstable.
- There is no “loose movement”; i.e. if the plane rolls, it does not keep rolling after the pilot let off the stick.
- Roll and Yaw are symmetrical.
- The wings do not bend too much (or brake) at high Gs.
Control Surfaces[]
Elevators[]
A “must have” on every plane. Control pitch. Generate more or less lift causing the plane to pitch up or down. On real planes they are usually located at the back of the plane, sometimes being a part of a horizontal stabilizer
Ailerons[]
A “must have” on every plane. Control roll. Generate more lift on one side of the plane, causing it to roll. On real planes they are usually located at the sides of the wings as far from center as possible.
Rudder[]
Controls yaw. On real planes it is usually located at the back of the plane, being a part of a vertical stabilizer. Some planes have two, mirrored vertical stabilizers with two rudders.
Canards[]
Canards are small wings in front of the main wing. Canards as well as extended leading edge (front part of the wing) increase maneuverability, also at high AOA. In Besiege they allow to have a control surface ahead of CoM to significantly increase movability. Also might be hidden inside the fuselage (make sure that they angle in the proper direction while pitching).
Leading Edge Slat[]
Does not work in Besiege as aerodynamics are not properly simulated. Might be a cosmetic feature.
Flaps[]
In Besiege, they are just additional Elevators. They create more lift and when the plane flies at lower speeds they allow it to maintain stable flight or slower descend, for a price of increased drag.
Air Brakes[]
A surface that controls speed by significantly increasing plane’s drag. At high speeds most RTCs might not have enough power to fully extend the air brake with actual propellers or wing panels so other methods are used to imitate it; e.g. reversing the engine, or using Nives or Overflow.
Passive Air Brakes[]
Always active air brakes are used to increase the planes drag. They must be aligned with CoM, or they will cause pitching up or down. Because the planes in Besiege can have very minimal drag in relation to their engine’s thrust, passive air brakes are added to make planes feel more natural and realistic, and allow them to bleed the energy during turns. The drag might be reduced by changing brake’s angle.
Weapons[]
Guns[]
In Besiege, Cannons are usually the most important and versatile weapon on the plane. High power cannons allow to deal more damage and have higher muzzle velocity, making it easier to hit moving targets. High rate of fire (RoF) makes the recoil more consistent and easier to counter, usually done with nives.
Cannons in besiege have a random delay before shots. Because of that it is impossible to use two cannons to cancel yawing caused by recoil after shot; therefore, cannons should be as close to CoM as possible.
HUD or any other aiming device should be aligned with cannons. It might be tested in 0 Gs. Crossbows only damage wooden parts. Unless the target is entirely wooden or the arrows hit a critical wooden part, crossbows are pretty much useless.
Other Weapons[]
In Besiege there is a variety of easy to build A/G and A/A weapons.
Rules for building planes also apply for rockets and bombs. Heavy payload changes CoM (and also CoL if propellers are involved), as well as dropping it. Heavy bombs, etc. should be attached as close to CoM as possible. Make sure that the plane’s landing gear is able to support the plane with the payload and land with it. Check if the plane is able to takeoff and land in a reasonable space.