KerbalX

Details

• Type: SPH
• Class: aircraft
• Part Count: 131
• Pure Stock
• KSP: 1.12.3

Harpy VTOL

A stock aircraft called built with 131 of the finest parts; its root part is ServiceBay.250.v2.

Built in the SPH in KSP version 1.12.3.

I saw Sandubba’s beautiful Stratz VTOL on YouTube and was inspired to build something similar: a jet transport with VTOL capability. My design doesn’t have the same visual elegance, but I did eventually achieve my goal while sticking to my preferences of minimal clipping and visual mods only.

Manual

Harpy uses landing struts so it can only take off and land vertically. Stage, activate RCS and SAS, then increase the thrust on the vertical jets using the RCS up/down controls (K).

For very short hops you can stay in VTOL mode but Harpy is designed for sustained flight. Its range is about 1300km, which is enough to go a third of the way round Kerbin.

To transition to forward flight, whack the main throttle up to maximum and deploy flaps (9). Once your altitude and speed are over about 200m and 50m/s respectively, retract the flaps (0) and reduce the thrust a bit on the VTOL jets (I). Then deactivate the VTOL jets (1) and RCS, retract the landing gear, and close the bays (2). It flies like a conventional aeroplane.

To land, reduce the main throttle to about two-thirds, reverse thrust (6), and deploy flaps (9). Open the bay doors (2) and fire up the RCS and VTOL jets (1). When your speed drops to about 40m/s, cut the main throttle to zero, normal thrust (6), retract flaps (0), and increase thrust on the VTOL jets (K/I). Pitch up and adjust VTOL thrust until you’re hovering. Deploy landing gear. And come in very gently! Turning on lights will help as the landing light beams intersect directly below the forward engine.

Design notes

The VTOL engines - three Panthers with afterburner permanently on - are in three service bays spaced along the main fuselage. These bays also hold the main landing gear and lights. Taking off requires an awful lot of static suction, hence the many intakes.

Fuel is carried in 36 Mk0 fuel tanks which are stacked inside 2.5m engine plates. Interestingly, the service bays can’t be opened or closed in flight if they’re adjacent to the engine plate.

The C7 adapter carries mostly oxidiser for the vernier engines. Feel free to adjust the quantity depending on how much hovering you plan to do - just be careful not to throw off the balance!