KerbalX

Details

• Type: SPH
• Class: ship
• Part Count: 48
• Pure Stock
• KSP: 1.11.0

Mods

• Squad (stock)

The KT-200A Skyrider is the first in a series of medium-sized space planes (the 200 series) meant for training purposes. It is entirely stock-built although some addons such as TweakableEverything and TweakScale may be necessary. I also highly recommend the use of Atmospheric Autopilot which will make aircraft operation much easier although flying with just stock SAS is certainly possible.

The Skyrider uses two sets of engines which allows it to be operated both as a conventional aircraft with both high speed and high altitude potential and as a horizontally launched space plane capable of orbital flight.

The single Panther afterburner turbofan allows for atmospheric speeds in excess of Mach 4.5 at higher altitudes in wet mode and can carry you up to an altitude of 17k to 20k. It can also operate at lower attitudes in dry mode where it has a maximum altitude of about 7k to8k and operates comfortably at both subsonic and supersonic speeds.

The pair of NERVA (Nuclear Engine for Rocket Vehicle Application) engines are highly efficient engines for use in space however they have acceptable performance in the upper atmosphere but should only be used for planned suborbital and orbital missions.

Atmospheric Operation

The dry mode of the Skyrider’s Panther engine allows it to operate comfortable at subsonic speeds giving it considerable range with a service ceiling between 7k and 8k. It should provide about 85 kN of thrust while stationary with upwards of 100 kN at higher subsonic speeds, it tops out at 107 kN around Mach 1.8 even is probably only achievable with afterburner boosts.

While the focus of the Skyrider isn’t subsonic travel it still has considerable lift capabilities allowing it to operate even at fairly slow speeds with landings successfully performed below 40 m/s. It can also execute emergency water landings even very minimal damage, usually the loss of the Panther engine but otherwise intact.

The wet mode of the Panther engine can push the Skyrider up into hypersonic speeds in excess of Mach 4 at higher altitudes, usually as a step towards space flight. It provides twice the thrust of dry mode but at double the fuel cost and half of the specific impulse. It can be used for sustained flight – usually for space missions – or just as a brief boost for takeoffs or when otherwise necessary.

Suborbital Operation

A takeoff for a suborbital mission should always be done in wet mode so that you gain speed more rapidly with your initial climb. It is possible to make the initial climb up to about 7 km to 8 km in dry mode at the expense of time that might save you a bit of fuel but my experience didn’t save any significant amount of fuel.

Since this is a sub-orbital operation you can maintain any climb rate that doesn’t cause a significant drop in speed or vertical speed. You should aim for reaching at least 750 m/s by the time you reach 10 km to 14 km and not allowing it to drop as you make your engine transition. You can potentially wait on your engine switch up as high as an altitude of 22 km and might want to experiment to determine the best moment.

The switch to the NERVA engines will result in a considerable drop in thrust to about 104 kN at 14 km up to 110 kN at 22 km. This means you already need considerable surface speed, about 750 m/s, before you make your switch. You’ll definitely encounter an immediate drop in vertical speed and Time to Apoapsis but simply maintain a positive angle-of-attack.

You should be initially conservative with your angle-of-attack and I recommend your pitch rate between 5 and 10 degrees until your vertical speed and Time to Apoapsis stop dropping. Once they stabilize feel free to increase your pitch rate for a more vertical flight. You should keep an eye out as your TWR (thrust-to-weight ratio) increases until it hits 1.0 and at that point you shouldn’t have any trouble reaching space.

You should keep in mind that a flatter trajectory will afford you more re-entry time and a shallower re-entry while a more ballistic trajectory will result in a higher altitude but a much steeper re-entry and possibly making your landing more difficult.

Orbital Operation

Your takeoff and initial ascent with the Panther engine will be about the same as a suborbital flight although you should always keep your pitch rate around 5 degrees to help with the gravity turn since in this case you want an orbital trajectory. You’ll want to wait as long as possible before the engine switch which is possible with the recommended pitch rate – my orbital flights usually switched around 20 km.

Your ascent with the NERVA engines will start similar to suborbital flights but you’ll always want to keep to a pitch rate between 5 and 10 degrees until you have passed a TWR of 1.0 after which you can simply point to prograde until your estimated apoapsis sits around 80 to 100 km. Since you spend much more time in the atmosphere as opposed to a high TWR rocket you’ll want to give yourself a wide margin for estimate losses due to atmospheric drag as you coast towards space.

If you’ve followed my recommendations you should still have 300 to 400 dV left upon reaching space and should only need 60 to 80 dV to stabilize your orbit. I recommend reaching a stable orbit first before making any orbital adjustments and you should have 200 to 300 dV for adjustments, other operations, and your re-entry burn.

Since this is a trainer space plane I haven’t included RCS thrusters but have included capable electric capacity along with some small solar panels so you shouldn’t get skip in orbit due to a lack of electricity. You should keep enough fuel for your re-entry burn and additional fuel reserves will allow you to operate the Panther during your approach – although this isn’t strictly necessary.

Re-entry, approach and landing

Your re-entry burn should be as precise as possible if you want to approach and land on one of the runways – certain addons may aid with that although space plane landings can be difficult for many players. How you handle your re-entry and approach will also have a considerable effect on where you can touch down – saving fuel to operate the Panther will help somewhat.

You should attempt to keep an AoA of between 30 and 60 degrees in the upper atmosphere so you can bleed off speed although the Skyrider is fairly stable during re-entry so you can attempt to make some wide s-turns to help with that. You want to still have at least a surface speed between 100 and 200 m/s as you begin your approach so you can make corrective turns and small climbs as necessary.

If you are making an entirely unpowered glide during your re-entry and approach then keep in mind you want to get down to 800 m/s by the time you hit 20 km and sit around 200 m/s once you hit 10 km and about 40 km from your intended landing location. If you are more than 40 km from intended location you probably won’t be able to reach it unpowered.

If you reserve some fuel for powered flight this gives you some leeway and can effectively double or even triple the range of your landing depending on how much fuel and how conserve you are with the throttle.

The considerable lift of the Skyrider’s wings should let you float down pretty smoothly and want to be slower than 60 m/s as you make your touchdown, if it’ll be a rough landing you improve your chances of survival with an even lower touchdown speed. If you have managed to make it to a runway then remember to slightly flare up so your back wheels touch the ground first to avoid a violent wheel barrowing.

Built in the SPH in KSP version 1.11.0.