Balloon

Balloon
Block Type	407 Flight
Mass	0.22
Friction	0.6
Drag	1
Dimensions	1.9 x 1.9 x 1.9
Weaknesses
Breaks	1 hit
Freezes	Yes
Burns	Yes
Break Forces
Bottom	45000
Top	-
ID	43
Version Introduced	v0.04

The Balloon is a machine block which pulls things into the air.

Settings

Parameter	Default Value	Range
String Length	x2.00	x0.00 - x6.00
Buoyancy	x1.00	x0.20 - x1.50

x1 Buoyancy translates to approximately 0.845 units of mass. Remember to account for the balloon's mass as well.

Usage

The obvious usage of balloons is to lift things. In this role, they are simple and effective, and the block of choice for many when starting on their first aerial vehicle.

You can greatly alter the length of the rope holding the balloon - make it long to get it out of the way, or make it short to reduce flop and instability.

The downsides are that they are

• fragile - arrows, melee, sharp weapons, and slight collisions can all prove fatal
• weak and bulky - many are required to lift even a moderately-large machine.
  

How much?
Given a certain mass, you need total buoyancy of approximately $1.183 \times mass$ to remain in the air. You may be spending one balloon for every two or three blocks.
(see the Trivia section for details)

With Scaling and NoBounds, at least, this second point is eliminated - they can be scaled small and cranked up to extreme values.

Force Formula

From the balloon's code, we can observe that the upward thrust delivered by a balloon is equal to $F = lerpedPower \times Buoyancy$.
$lerpedPower$ starts at 0 and ramps up to $liftStrength$.

Given that (as verified with Object Explorer):

• $liftStrength$ is set to 28
• Acceleration due to gravity is 32.81 m/s²
• $F = mass \times acceleration$

the precise formula can be derived as $buoyancy \approx 1.171786 \times mass$.

However.

The determination of when to stop ramping is not when $lerpedPower$ hits $liftStrength$; instead, it stops when the time counter is above a certain value. The time counter is incremented on each frame - and the time between each frame is not constant. There is always a random margin of error.

In practice, the formula is closer to $buoyancy = (1.18 + random(0, 0.03)) \times mass$ and the error depends on your frame rate.

Technology

As a component, balloons are an integral component in the aptly-named Balloon Stabilisation method. The fact they always pull upwards can be exploited to great effect.

They are also used to counteract the weight of bombs and other detachable components on aircraft where precision tuning is necessary.

See Also

• Basic Flight