KerbalX

Details

• Type: SPH
• Class: spaceplane
• Part Count: 371
• Pure Stock

Hearts Chevron 96 Cargo Lifter 25MCP

Hearts Chevron 96 Cargo Lifter. Hearts Chevron is named by the shape of the engine blocks that form a heart or chevron pattern. In flight it forms this unique contrail pattern. The 25MCP version standing for 2x5,2meter central parallel referring to the pair 5,2m fairings cargo hold.
It has 96 rapier engines hence the number 96. It can lift up and carry 1400Ton+ to orbit with a payload fraction of 50-51%
One rapier will carry 28.5Ton of weight.
I made this space plane so I can use a single version to haul almost any volume or weight to LKO for superb fuel economy. It is only meant to be used as such, namely a cargo SSTO to and from LKO. Only intend to haul cargo to 71-75/71-75km orbits unless you can’t resist.
Make sure the cargo is distributed evenly and that it is moved so that the center of mass is below the center of lift (directly).

IMPORTANT

Securing vessel rigidity becomes riskful when using fast and immediate turns or control input at high speeds especially when payloads
past 1100Ton are used. While it is safe to use the max payload it requires you to pitch gently through the course of the flight especially around and above 400m/s.
For that reason it is best to use Mechjeb Smart A.S.S. Surface mode to navigate the spaceplane to orbit. The instructions below are written for stock.

INSTRUCTIONS

1. Full throttle and accelerate past the last 2 blocks at the end of the runway and hold S to takeoff. Get the nose to 5° and stay near sea level to accelerate.
2. Activate 2x timewarp and use W,A,S,D,Q,E, to stay near sea level to accelerate.
3. Activate SAS stability assist when past 400m/s and push the nose a little below the horizon as it will rise when trying to stabalize. Keep accelerating but don’t touch any controls except roll until you reach 9km altitude, the nose may naturally rise as you climb.
4. At 9km the nose would have naturally risen up to about 8-10°. Pitch the nose down to 5° by holding W. Keep tapping and holding W but don’t hold longer then 2 seconds not to cause sudden pitch.
5. Keep accelerating to 20-23km altitude with the intention to achieve ~1600m/s+
6. Activate RCS and Action group 1 to toggle all rapiers to closed cycle mode and rise nose to 10°
7. Keep at 10° until vertical climb is at 300m/s+ and hold prograde (hold S and/or W to lead to prograde as SAS is stubborn.
8. Activate RCS action group to toggle Fuel cells for EC generation.
9.Use action group 3 and/or 6 to toggle engines for Center of thrust if Space plane tends to pitch up or down (depending on payload) This usually happens when nearing orbital velocity or above 31km altitude.

Tip: Spaceplane has very little cross section with a lot of weight and doesn’t slow down easily. You can get MECO at a Apoapsis of 70+ Km as low as 34Km altitude and then drift to Apoapsis without losing to much velocity.

10. Use Action group 2 through 6 i[/i] while throttling at Apoapsis to circularize. i[/i]

Tip: Keep toggling any of the engines modes on/off to keep the nose at prograde when payload requires it as there is no other means to stay oriented in the upper atmosphere/space.

Explanation

The reason I chose this method of controlling pitch on the space plane is because for large cargo, excellent performance and balanced stability throughout flight while including universal cargo types insisted to use a engine placement that was mid center.
The unfortunate side effect is that you will have to do a little bit of practice to do it right. It is very easy and straightforward when getting the hang of it. Just F5 and reload if you mess up.

11. Activate stage to deploy fairing, use the last stage to decouple cargo i[/i]
12. Rotate retrograde. Toggle off action group 3, 5 and 6 and toggle between 2 and 4 while throttling to stay balanced.
13. Dive your Periapsis as low as you want (can)
There are 2 ways to do a re-entry.
a. You can dive to your Pe while holding prograde. Wing incidence makes the space plane skip the atmosphere. If you want to reverse that effect you can roll the spaceplace on the side or back and vice versa. The spaceplane can get below 25km altitude due to heat resistance.
This way you can aim your way over the KSC and then use the brake action group to activate spoilers on all control surfaces u[/u] Alternatively you can do a Flat body aerobrake also.
b. Use 90° through 50° degree AoA depending on atmospheric height using SAS stability assist.

IMPORTANT

You will not be able to push the nose down after a flat body aerobraking unless you do the following.
Push W to lower the nose then pull up using S all the way to 90° if possible and then hold W until the nose dips down to prograde.
If you don’t do this you will be in a irrecoverable flat body stall until below 200m/s. Best is to get to prograde when at or below 1100m/s. Below that speed you may need to repeat the pushing and pulling sequence a 2nd time. Think about a swing that needs to wind a 2nd time.
Activate Brake action group to deploy spoilers on all elevons before landing to lose the last 100 m/s or more.

Tip: You should be able to navigate to KSC using the methods easily, in a emergency the space plane can land on water when empty.