KerbalX

Details

• Type: SPH
• Class: aircraft
• Part Count: 24
• Mods: 2
• KSP: 1.6.1

Mods

• Squad (stock)
• TweakableEverything

Aircraft Characteristics

Crew: 1

Dry Mass: 2,745 kg

Wet Mass: 5,290 kg

The KT-11A Finch is one in a series of trainer aircraft I’ve built with different series’ representing different categories such as the 10 Series representing small aircraft meant for subsonic operations. They are entirely stock-built although some addons such as TweakableEverything and TweakScale may be necessary.

The Finch is a small rear-mounted single jet meant to operate at subsonic speeds (below 384 m/s ASL) at short ranges of approximately 300 km although I recommend missions that don’t exceed 270 km to provide you with a considerable fuel reserve. It’s designed for fairly easy operations and will take off on its own either with no or (inner) flaps actively deployed.

In theory it can reach a maximum ceiling of 8,639 m with increasingly smaller and smaller climbs with its engine still able to operate in the thinner atmosphere – however you may easily exceed the service range by trying to attempt it. The service ceiling of 6,785 m allows for a higher altitude flight that can be reasonably accomplished within the window of the service range although it may be excessive for the needs of most missions. I have defined a cruising altitude of about 4,211 meters which should serve the purposes of missions, is pretty fuel efficient, and doesn’t require an exceedingly careful climb rate.

You should keep in mind that the Finch has some difficulty in quickly recovering from a steep climb or uncontrolled descent so always give yourself a wide margin and handle climbs with a considerable amount of speed and sharp descents with a considerable amount of altitude.

The max speed at seal level (ASL) sits around 184 m/s but the flight envelope allows for even greater speeds in reaching 190 m/s at cruising altitudes and even exceeding that at altitudes closer to the service ceiling. The Finch is entirely a subsonic aircraft that won’t even get anywhere near terminal velocity except under the conditions of a steep descent.

The deployment of flaps, specifically the inner control surfaces on the wing, greatly reduces your max speed to around 70 - 80 m/s in exchange for some additional lift and a slightly reduced stall speed. This allows you to quickly slow down the aircraft considerably without having to adjust the throttle or significantly changing your AoA (Angle-of-Attack).

The deployment of the flap brakes, specifically the outer control surfaces on the wing, in combination with the flaps allows you to rapidly reduce your airspeed. It will brings down your max speed to around 51 m/s and puts it in line with your final threshold speed for touching down. It also has the effect of providing even more lift and reduces your stall speed even further.

Takeoff Procedure

The normal takeoff procedure is handled with flaps being deployed, SAS activated, and throttled immediately deployed to full. This approach should lead to a gentle roll down the runway with lift occurring without pilot input at about 63 m/s and if flaps haven’t been deployed then it will still occur but at 73 m/s.

Do not apply the outer flaps or flap brakes at any point during takeoff.

You should continue as an ascent for at least 50 to 100 meters before raising your flaps and landing gear in case of a sudden loss of lift upon takeoff. After that point you can adjust your speed and rate of climb through pilot input.

Approach and Landing Procedure

There are many different approach and landing procedures depending on your choice of field and runway so I’m going to cover the approaching and landing on KSC Runway 027 which if you take off from KSC Runway 090 it’s simply turning around and going for a (mostly) straight-in approach.

Your KSC Runway 027 approach should begin at an altitude of approximately 1,222 km (1,151 km AGL) and about 22 to 30 km from the KSC at a speed of about 75 m/s with flaps deployed. You should begin a 3 degree descent along with the goal of reaching 176 m (105 m AGL) about 2 km from the runway and gradually reducing speed to about 50 m/s with minor adjustments to your throttle and heading to stay on the glide slope.

The final approach begins t about 2 km from the end of the runway at which point you should be at an altitude of 176 m (105 m AGL) and at a speed of approximately 50 m/s with both flaps and landing gear deployed. You should avoid completely killing the throttle since you are already very close to stall speed which could cause you have an accelerated plummet into the runway.

When you are within about 10 meters above the runway you should flare up by slightly raising your nose so that the rear wheels hit the ground first to avoid a violent wheelbarrow impact with the ground. Once all your landing gear wheels have touched the runway you should immediately kill the throttle and start applying the brakes. If you have done everything correctly you should be sitting in the middle of runway in one piece.

Built in the SPH in KSP version 1.6.1.