How to balance a VTOL

[Fireheart318]

Step 1: Get a plane. Many VTOLs are purpose-built and you've probably already gotten everything else laid out

Step 2: Check the fuel drainage. This probably won't be as big a problem if you build planes the "traditional" way with most of the fuel in the back. When it drains, the center of mass moves forward. You'll probably want an RCS unit or reaction wheel just in case but often the cockpit wheels do the trick.

Step 3: Activate the center of mass and thrust icons. As I said before, weight distribution will be more or less the same as it was before as you're only adding mass to the center of mass, however if you use jet engines (which you probably are), they have a weird CoM (due to realistic jets having a bunch of heavy moving parts inside the main body of the craft), so it may be moved upward slightly. If this happens, just move the wings up or lifting engines down a bit. If you still can't solve this problem, assuming you're using Wheesleys, turn the assembly upside down and turn on reverse thrust. This will make your craft even more stable in the air, making it hang like parachute due to the upward center of lift/drag

Step 4: Deactivate the other engines. Assuming this uses lifting engines and standard engines, you'll want to set the standard engine thrust limiter to 0 (limiting 100% thrust). This way, the only factors affecting the center of thrust will be the lifting engines.

Step 5: Select a lifting engine and mounting surface. I like to use either Junos or Wheesleys depending on the function (I'll elaborate on that later). As for the mounting base, you'll probably want to use an octagonal or cubic octagonal strut - they're light weight, small, and have two attachment nodes when mounted on a surface - allowing you to add more intakes which VTOLs often need.

Step 6: Assemble the lifting assembly. Start by attaching the mounting base to where you want your engines to be (I'd recommend the wings as they are often  convenient and there's two (or more) of them) and then rotating it so the nodes are vertical. Next, add the engines to the bottom of the assembly and make sure they clear the ground and put the intakes (if you're using extras) on the top. You may want to clip the engine or intake into the mounting base and the surface into the wing for a much cleaner look

Step 7: Fine tuning. You'll probably want to get rid of the center of lift icon for this. Start by offsetting the mounting base so that it aligns with the center of mass and then you may want to move it inward a little to decrease it's moment of inertia (the more weight on the outside, the longer roll will take, same with pitch and yaw) so it's faster to respond to roll commands.

Step 8: Re-enable thrust on the standard engines and set action groups. I like to use 1 for lifting engines and 3 for standard engines

 

There, you should now have a well functioning VTOL or STOL. There are many uses for these craft and the engines don't have to be strictly for takeoff and landing - some of my favorite fighters like the DOVE 1.1 (upgraded DOVE) use Juno engines for linear maneuvering based on roll and also aid greatly in pitch-based maneuverers. These abilities are great for dogfights and attack runs because you can move in ways your opponents (probably) won't expect or be programmed to expect and can also get you out of a pinch easily. I've pretty much gone through everything I know here so Fireheart318 out!

Edited May 7, 2016 by Fireheart318

[msasterisk]

Great tutorial, but you should probably make them in the Tutorials section.