KerbalX

Details

• Type: SPH
• Class: aircraft
• Part Count: 43
• Mods: 2

Mods

• Airplane Plus
• Squad (stock)

Description

A mod aircraft called Hawkmoth VTOL (Fairing Edition). Built with 43 of the finest parts, its root part is Mark2Cockpit.

Built in the SPH in KSP version 1.3.0.

This is a VTOL modification of my Hawkmoth jet.

I focused on adding VTOL capabilities without losing much of the speed the original had.

The challenge here was to somehow mount the vertical engine in a way that does not introduce a lot of drag.

As this is a Mk1-based jet, the Mk2 cargo bay was out of the question, and there is no (stock) Mk1 cargo bay. (See also the Service Bay Edition of this craft for a version that uses these).
There are mods that come with Mk1 cargo bays (Airplane Plus and Modular Rocket Systems), but the problem with them is that they don’t shield their cargo from drag at all - not even completely contained parts that don’t clip to the outside and that are properly attached to the inside nodes and not the inside surface. This is a bug in my opinion.

I also tried the Interstage Fairing Adapter from the Procedural Fairings mod. This one had the problem that, while it shielded its cargo fine, the part that comes after it (e.g. fuel fuselage) still received a lot of drag.

Then I discovered that the stock fairings also support interstage mode. I tried that, and it works. It’s a bit tricky if you want parts to clip to the outside (add them after you draw the fairing shape), but it’s possible, and the parts are still shielded from drag.

This version uses one mod, and that is Airplane Plus. It uses the half-length Mk1 fuselage to put the vertical engine between two of these to be able to align the vertical thrust vector with the center of mass.

Talking about mods - I found RCS build aid very helpful for building VTOLs, as it can show the dry center of mass together with the fully fueled center of mass, without the need to remove the fuel from all fuselages all the time. This mod is not yet officially released for KSP 1.3, but linuxgurugamer did a great job making a beta version of it that works with 1.3. You can find it here: https://github.com/linuxgurugamer/RCSBuildAid/releases/tag/0.9.1.1
With the help of this mod, I was able to perfectly align the two centers of mass, so the CoM does not move at all (horizontally) with fuel consumption.

This VTOL version lost some small amount of top speed compared to the original, but it’s still fast. The range is also decreased.

The engine overheats at full throttle. The sustainable cruise speed lies somewhere between 800-900m/s depending on the altitude. I tried using radiators, but while they help reducing the heat, they cause a LOT of drag.