(Note: this post is a part of a larger guide pertaining on how to build missile using Triton Aerospace's code.)
What you will need:
◆ (1x) Missile Guidance Code [Triton Aerospace] This is the command part with the guidance code inside. Change its part name to either AAM1, AAM2, AAM3, AAM4, or AAM5.
◆ 1 nose cone, on top of the command part. Name it Warhead. Using the green arrow, adjust its length to be 1 meter or less. Then go into tinker panel, edit hidden properties, fuel tank, fuel type, and enter in PETN. Then go to config, and increase explosiveness from 0 to anywhere between 2 and 2.75.
◆ At least one fuel tank with solid fuel. Place this behind your command part. Enable Advanced Properties, then in the tinker panel, increase Stability Modifier from anywhere between 3 and 8.
◆ One solid fueled engine behind the tank. Make it reasonably sized so that it fits in the rear of your fuel tank. Aim for a burn time of anywhere between 4 to 12 seconds.
◆ Attach one set of x4 symmetry wings in the rear or middle of your missile on the fuel tank. Make sure the angle for the four wings are 0 or 360, 90, 180, 270. First, remove the control surface. Set the part scale size in the tinker plane to 40% via the slider. Then, adjust the size of the wings via the blue arrows until it looks reasonably sized. Finally, ensure you are using Symmetric airfoil, not fin airfoil. These are your missile's lifting wings.
◆ While keeping x4 symmetry on, attach 4 Rotators (NOT Hinge Rotators) on either on the front of the fuel tank (if your lifting wings are at the rear), or at the rear of your missile (if your lifting wings are in the middle). Make sure the angle for the rotators are also 0, 90, 180, 270. Set the Size to anywhere between 25% and 50%. Set the Base style to None, then adjust the Range to be either 30 degrees or less, and set the Speed to 100%.
◆ Next, while still keeping symmetry on x4, add 4 more wings on top of (on the shafts of) the rotators. As with the previous wings, make sure to delete the control surface. Set the part scale size in the tinker plane to 40% via the slider. Then, adjust the size of the wings via the blue arrows until they are considerably smaller than your lifting wings. Finally, ensure you are using Symmetric airfoil, not fin airfoil. These are your steering wings. If they are in the front of the missile, they are front steering wings. If they are in the rear, they are rear steering wings.
You want to make sure your missile is 6m or under in length. And less than 0.6m in width and height. If you followed the instructions exactly, your missile should look something like this:
Congratulations, the most basic building step is complete!
However, this missile is rather rudimentary. It features low delta v, it isnt protected against high heat, and the rotators sticking out look ugly.
Tucking in those rotators
Because the rotators look ugly sticking out, we want to move them inward to prevent gaps. First, ensure that 4x symmetry is still enabled for the fins. Then using the offset (RGB arrows) tool, click on the fins, and offset them a small amount away from the center of the fuel tank and rotators. Next click on the rotators and click group parts. Finally, using the offset (RGB arrows), offset the rotators to inside the fuel tank until the wings are flush with the surface of the fuel tank.
Low Delta-V:
There are several ways to increase this. You can get a more efficient engine or more efficient fuel mixture. You can decrease dry mass on your missile. You can add a bigger fuel tank (works up to a point). However, another somewhat obscure technique is to raise the Utilization of your main fuel tank.
Found in hidden properties, Utilization determines how much volume of the fuel tank is allocated for fuel. The default value is -1, which correlates to about 55% of your fuel tanks space being taken up by fuel, which is actually pretty mediocre. To increase it, open Hidden properties, navigate to Fuel Tank, then change utilization to anywhere between 0.7 to 0.9. This correlates to 70% to 90% of the fuel tanks volume being taken up by fuel, respectively. Make sure to press "Apply". Next, go to your Fuel Tank and adjust the fuel in it using the sliders until its zero. Finally, set your fuel to the maximum amount allowed by the sliders. You will notice you have significantly more fuel than you had before. That is the power of Utilization.
High Heat Protection
Juno: New Origins, compared to real life, has a generous default part heat tolerance of 1500 Kelvin (1226°C, or 2240°F) for most parts. Parts that do not exceed this temperature will never take damage. However, when using air to air missiles, especially capable ones that can fly extremely fast, heating quickly becomes an issue that can result in a Rapid Unscheduled Disassembly (RUD). This is due to individual parts exploding and disintegrating from the high heat. To prevent this, you want to open the tinker panel and increase Max Temperature to 3000k (kelvin) FOR EVERY PART ON YOUR MISSILE. This is enough for you to not worry about heat in most situations. If you want to be extra careful, you can increase Max Temperature even more in hidden properties, under the Config tab.
Your missile should now look like this.
Before we advance to the next step, if you would like to add textures or new colors to the part's, you are more than welcome to now.
Rotator Input Setup and Orientation Check
It is now time to add inputs to your missile's rotators that move the steering fins. If you remember or actually read this guide, early on, we made it very clear that both sets of wings and rotators needed to be aligned at 0, 90, 180, and 270 degrees. On both front and rear cross section aspect, there should be 1 lifting wings and 1 steerable wing pointing up, down, left, and right, with 8 fins in total, like this.
Your Command Disk that contains the guidance code should have this orientation: Red arrow facing to the right, green arrow facing forward (towards the white front arrow in the craft designer), and blue arrow facing down.
Now it is time to set up your rotator inputs so that your steerable wings can steer! First, click on any rotator, then go to the symmetry section, and click Break Symmetry, then press Okay. This will remove on the fly updates for all 4 steerable wings and rotators, so that you can add the inputs one at a time (you must do this).
These are the inputs for FRONT STEERING MISSILES (viewed from the rear).
Note that the pitch axis is aligned with the red arrow and the yaw axis is aligned with the blue arrow. The pitch rotators on the right has invert on, while the yaw rotator on the top also has invert on. Both of the pitch and yaw rotators across from the inverted ones has invert OFF.
For REAR STEERING Missiles, the pitch and yaw inputs are in the same locations. HOWEVER, the location of the Invert On and invert OFF inputs are REVERSED.
IMPORTANT: DO NOT USE Invert on mirror for ANY inputs whatsoever. Doing so will cause confusing and increase chances of you messing it up.
At this point, your control inputs are fully set up, so you can actually spawn the missile in mid air and test out the controls. Check out this video where i test the controls of the tutorial missile i made.
HELP! My missile spins out of control or rolls when I use pitch or yaw!
If your missile is spinning out, it is very likely because the missile's center of lift (COL) is in front of the center of mass (COM). For a naturally stable design, the center of mass must always be in front of the center of lift. You can do this by reducing the wing area on the wings on the front or middle of the missile, while making the rear wings larger. Additionally moving the leading edge back will often significantly move the center of lift backwards.
If your missile is rolling when using inputs, it means you setup your inputs wrong. Please refer back to Rotator Input Setup and Orientation Check for details on inputs for front steering and rear steering missiles. Additionally, the fins could be angled improperly, or you did not use Symmetric airfoil.
If your missile controls as expected, you are ready to move on to the final step!
Activation Groups
Dont worry! This section is a breeze, and is very short. When the missile is told to launch, it activates several lines of code and parts within itself. A good portion of those are broadcasts, which are handled automatically. However, you still need to sort 3 Activation groups:
- Detach Missile
- Motor
- Fuse
They are quite self explanatory so go fill them in! Make sure not to leave any default activation groups.
Now, bind the solid motor to Activation Group 2.
Finally, we need to add a side interstage to our missile, so that we can attach it to a hardpoint on a jet. However, we also need to make sure the fins dont clip the jet. To prevent this, click on the command part, and press group parts. This will group the entire missile. Next, while still selecting the command part, use the rotate tool and drag the green circle handle 45 degrees left or right. The direction doesnt matter. Your command part's X angle should be 45 degrees. Then, add a side interstage, reduce its size to 25%. Bind the Side Interstage to Activation Group 1. Finally, click the command part, click to ungroup all the parts, and then click to group all of the parts in the missile again. Then, save your creation.
You are done!
I hope you all found this part of the missile building guide helpful. If it feels like a lot to digest, thats because it is! Feel free to spend as much time as needed soaking in the steps and comprehending them; you are on nobody's time but your own! And If you feel concerned that all missiles are going to look bland or limited by the same construction techniques, dont be! While most missiles built share the same core building principles, they also are very unique in their own ways! Additionally, there are even more advanced missile building techniques that I wont get into for this guide as its meant as a beginners guide to air guided missiles, but know that they exist!😉
For the next part of this guide, we will be taking a look at the various parts of the missile's guidance systems, the different variables that need to be tuned, and even the plane we will be using to test these missiles!
See you there!
@TritonAerospace There is more to come!🔥