- Updated some descriptions
- Added propeller roll correction
- Added thrusters & relation to center of gravity
- New example craft, Black Heart
- Added more image examples
- Added video

Balloons in From the Depths can be catastrophic to your airship if one is taken out. Here, using propellers will prevent this problem, and I will also explain how to make it self-righting. No longer will your ship awkwardly lean forward or to the side, you can even make a lop-sided craft and it will fly relatively straight. On top of this, when a propeller is damaged, your ship will NOT fall out of the sky, it will actually adjust for this change in lift and keep level flight.

In order for this to work, your airship must have at least one set of propellers situated to the right and left of the craft, and a set in the front and back. This will keep your ship from tipping forwards and backwards, and side to side. This means you need a minimum of 4 propellers to keep yourself from tipping over. You could get away with three propellers, situating one centrally, but that makes it way more likely for you to tip over (Not to mention more clumsy)

How self-righting works:

Make sure you set all propellers you want to keep your craft aloft with as "Always Up Fraction: 1.0"

You are going to need to make gratuitous use of automated control blocks. How the control blocks work, is that they trigger when the set parameter is applicable to the block, and not your ship. That means if you have a minimum/maximum altitude trigger, it will only trigger when the block reaches that height, not your ship. This is what we utilize to keep the ship upright. For every propeller, give it a set of automated control blocks, as close to the propeller as physically possible. Make sure you set their minimum effect range to only effect the nearest propeller. IMPORTANT: Make sure all of your automated control blocks are mounted at the same height on the vessel. If this can't be achieved, keep in mind: one meter in the game is = to one block, so if you were forced to set your control block 10 spaces higher than the others, it's altitude triggers would be ten more than the rest. Now, since you should have two control blocks by every propeller, and hopefully all level with each other, you can set your desired altitude. Set this by putting minimum and maximum altitude triggers, and make both values your desired altitude. It can range from... literally anything, as long as your propellers are strong enough to support your craft. To make it so that your vehicle will adjust itself, try to find the very limit to the propeller spin speed to where it starts to gain altitude. IE: If it doesn't gain altitude at spin speed 18, but does at spin speed 19, use 19 as a point of reference. (You may want to play around with motor drive beforehand to give yourself a lot of lift, I usually try to get my vehicle as balanced out as physically possible without using self-righting). With your bare-minimum of required power found out, set your minimum altitude trigger a good amount higher than your number (In this case 19). Do the opposite for your maximum altitude. I like to go by 3s or 4s, so my minimum altitude trigger would be assigned to 22, and my maximum would be assigned to 16. Note, you can use any number you want, as a higher minimum number will allow your craft to take even more of a beating, but may lead to a wobbly flight pattern. 3 and 4 are just my personal preference.

One of the propellers on Black Heart, and the control blocks inside:


Black Heart's rear propellers, with exposed control blocks:

In effect, you just created the parameters to keep your ship from tipping over. When a propeller falls below your desired altitude, it will boost it's propulsion to try to get back to your set altitude. On the opposite end, when it overshoots that altitude, it adjusts the propeller to let it fall, and when flying, is virtually unnoticable. It will stay locked at your set altitude, and it will take a severe beating to get it down. When parts of a propeller are knocked out, that particular propeller will just be trying to boost upwards more often, keeping your ship level. It is still recommended that you armor your propellers anyway. A shot hitting the base of the propeller will knock the whole thing out. I've had ships missing more than half of their propellers and they flew off on their happy way. What this creates is opportunity for fun. I love to add long barrel turrets to my airships, and this system allows you to turn them fully to the side without your airship capsizing. If you have a cannon with a particularly long barrel, it will have a tiny lean to it, such that it causes your airship to start circling a target in a circle of death.

Airship Skyfish shooting to the right, circling a target:


Airship Black Heart shooting to the right, not circling:

[Update]

Sometimes you can't mount your propellers ideally, so sometimes your ship may lean forwards and backwards, or roll side to side. The easiest way to remedy the pitch problem is to put tiny propellers mounted internally inside the front and back of your airship, hooked up to automated control blocks. You will need the parameter "If pitch > X" and "If pitch < X" triggers, with "Insta-spin the spin blocks" effect. The triggers or spin are swapped for the opposite propeller. (If you got it to work one way on the back propeller, the front propeller will be the opposite). This should keep your ship from tipping forwards and backwards, and keep it as level as the horizon.

For rear mounted propellers, you want to use:
Activate if Pitch Angle > X - Insta Spin the Spin Blocks
Activate if Pitch Angle < -X - Insta Spin Reverse the Spin Blocks
Front mounted propellers have opposite trigger or rotation

To help keep your airship from rolling, you do much the same as pitch correction, but instead you mount your correction propellers on either side of the craft, rather than the front and back. Instead of using pitch triggers, you utilize roll triggers.

For roll correction mounted on the right hand side of your craft, you want to use:
Activate if Roll Angle > X - Insta Spin Reverse the Spin Blocks
Active if Roll Angle < -X - Insta Spin the Spin Blocks
Left mounted propellers have opposite trigger or rotation

Airship Twinhook with very poor pitch correction:


One of the small pitch correction propellers within Black Heart

It is simple, add two thrusters facing outwards on either side of your airship. If they are mounted in the back, make sure they are set to reverse. To get your airship to utilize the jets, set it's aerial AI values to 0 - 180 - 0 from top to bottom. Your thrusters should now work assuming it has sufficient engine power.

[Update]

Your airship will experience wobble if you mount your thrusters higher or lower than the center of mass, or if you place only one pair on the front or back. Your center of mass is shown by a small weight symbol found somewhere within your craft. When placing your thrusters, make sure your thrusters are on the same height as your center of mass, or else it will start to tip it over when it turns. In a perfect world, you can place your thrusters an even distance away frontwards and backwards from the center of mass, but this isn't always possible.

Airship Skyfish with misaligned thrusters, leaning in a turn:


Center of Mass symbol within Black Heart:


Thruster alignment in reference to the Center of Mass on Black Heart: (Window on left side of turret)

Because you have set the self-righting mechanisms, you can mount weapons where ever the bloody hell you want, because your ship will automatically adjust for the added weight. Full metal turrets are no problem.

Scrapped airship design Hailstorm Prototype:


Full metal turrets on Black Heart:

These ships are NOT in the workshop.

References of Neptune Kai (Scrapped):


References of Black Heart: