Hearts Chevron 96 [EHEV] Extra Heavy Cargo Lifter.

[Aeroboi]

 

Hearts Chevron 96 [EHEV] *STOCK*

Extra Heavy Extra Volumetric Cargo Lifter.

[Carries ~12.5m wide and 60meter length cargo. Can lift ~1495 Ton into LKO/~1.5Kiloton @ 28.5Ton per rapier.]
For only 368 Parts which includes stock cargo!
Includes flight instructions below and on KerbalX

https://kerbalx.com/Aeroboi/Hearts-Chevron-96-Cargo-Lifter-25MCP
https://kerbalx.com/Aeroboi/Hearts-Chevron-96-Cargo-Lifter-2375MC
https://kerbalx.com/Aeroboi/Hearts-Chevron-96-Cargo-Lifter-75MC

1. Front side.

2. Belly with 2x3.75m fuel tank cargo setup.

3. From above.

4. Using the 2x5m wide fairing setup.

5. Takeoff.

6. On it's way to orbit.

7. From below

8. Nearing Orbit

Introduction
The name "Hearts Chevron" relates to the exotic rapier engine blocks. "The" Engine block on one of either sides is a 3x5meter engine mount each holding 16 rapier engines (48 total) on either side (makes 96)
In view of them they look either like a "heart" or a "chevron" (depending on ones viewpoint)
In flight they distribute that unique engine exhaust effect in it's contrails.
The 2375MC version for reference comes with only 368 parts, but mind you, that includes the 1450 Ton payload itself.

Explanation

I have been trying to build the largest, most part and aerodynamic efficient Rapier based cargo SSTO that can haul very heavy and very large payloads into LKO.
Most SSTO's are limited to cargo size either due to the space planes setup or being limited by cargo bays due to CoM, CoT and cargo width/length limits.

Usually people like myself build specific space planes for different cargo types for destined destinations. Typically a space plane can never carry more then a specific type of cargo weight or by volume based on the layout of the space plane or the cargo hold parts available in the game. While this space plane can have unique restrictions it should be able to haul anything into orbit that you could desire. Even if the payload should consisted of drag inducing outer parts that couldn't be faired the native engine thrust should be able to accelerate past 400m/s.
I require 96 Rapier engines to accelerate to Takeoff speed using the length of the level 3 runway at MTOW. But that amount of Rapiers is more then the required thrust required to break past 400m/s.
In theory/practice the space plane can always achieve past 400m/s even if it were to climb at 10° at MTOW so some minor drag shouldn't be an issue.

To meet it's specifications I tried to make a layout that can carry universal payloads both in weight and volume/dimension. I reiterated this design many times. Each wing segment is placed locally so it can absorb the greatest aerodynamic stress. All elements of flight on all 3 versions are tested and the space plane can perform all the requested takeoff and landing procedures you'd expect from a decent SSTO.

Directly under it's belly it can fit a 12.5m width rocket or space plane, even wider if it can stick out down below the outer mk3 fuel tanks until as wide as the closest engine block while being 60m long.

This space plane can be used with reasonable frame rates depending on amount of parts added as cargo assuming you use a modern computer. Parts in fairings will not be succumb to drag and will ignore many aerodynamic physics calculations.
You should be able to carry a several hundred part payload along with it on most modern computers when it's shielded inside a fairing.

I made this space plane so I can effectively haul very massive and heavy cargo for a very high fuel and cost efficiency to haul mother ship parts or fuel depot parts into orbit.When payload is properly faired it can carry 1495 Ton into orbit. For reference, in total it can carry 17 x Kerbodyne S3-14400 fuel tanks on the 2375MC version.

I have already created this space plane some time ago and have further optimized it's design characteristics and made 3 versions with several cargo attachment points. I consider these cargo attachment setups reasonable for most cargo weights and sizes.Tell me if you got any cargo you are unable to haul and I'll see if I can optimize the space plane further.

Why would I need such a space plane you'd ask? You'd say lesser efficient or less heavier space planes can haul the required cargo to orbit also!
However, if you want to build fuel stations, send space stations into orbit or haul ssto's into orbit using another ssto then this vessel should be able to do that.

Physical Time Warp

You cannot only use but are advised to use Physical timewarp.
I'd suggest to use 3x physical timewarp during takeoff roll (change back to 1x during takeoff itself)
Use 2 to 3x physical timewarp until reaching orbit (depending on computer hardware) If your computer is faster 3x should be the choice.

Instructions

Spoiler

 

• Always drag cargo so the CoM is placed directly under the CoL.
• Always strut each segment of the payload, preferably using autostruts (enable advanced tweakables in main menu general settings)
• Always drag spaceplane to the back of the SPH so it has the longest takeoff roll after attaching custom cargo.
• Push the throttle all the way forward and stage activate the rapiers.
• Start pitching up to 5° (use mechjeb) when you rolled passed (not passing) the 4 white stripe markers at the end of the runway. You can also raise nose lower then that but watch out you don't sink into the terrain after exiting the runway as the space plane tends to sink to fast below 5° at MTOW. At higher payloads you should achieve 120-130 m/s at the end of the runway.
• Keep at 5° all the way until 20-23km altitude at max throttle. In most cases (depending on cargo drag) you should reach ~1600m/s. Sometimes a draggier payload may require you to lower down to 3° nearing that altitude to reach 1600m/s which is advised when carrying max cargo. Using no autopilot mod you should use (ALT + W,S) to trim the nose so it flies level after takeoff and use action group 7 to activate front spoilers when above 400m/s to rebalance Center of lift.
• At 20-23Km don't wait until flame out but use action group 1 to activate the closed cycle mode when near or at (past) 1600m/s and keep at 5° until vertical climb rate is at 150m/s or thereabout and then hold prograde.
• Wait until Apo rises above 70km at least and then drift to Apoapsis while holding prograde. Depending on cargo the spaceplane can lose pitching control at or around 30km. If this happens toggle one of the engine toggling action groups (2 through 6) to re-align center of thrust.
• Timewarp to Apoapsis and do the circularisation burn. You are bound to use action groups to re-align thrust. Use quicksave first and test which combination of several dozen combinations forms the best thrust alignment. This depends per cargo weight and setup of course. If there is no mode that re-balances CoT properly keep toggling one of the action groups on/off to maintain attitude.
• Jettison cargo and then do pitch, yaw and roll retrograde and do the retro burn.
• The space plane can skip the atmosphere and can tolerate heat brilliantly. You can aim your Pe at the KSC as low as 30km and sink all the way to the other side of the planet while holding prograde while maintaining ~orbital velocities. If the space plane tends to skip above 30km nearing the ksc you can roll her sideways or upside down to reverse this effect. Use the brake action groups to activate all spoilers nearing the ksc to do minor controlled aerobraking.
  Alternatively *meaning* as usual you can do a flat body aerobrake up to 50° pitch in the lower atmosphere and 90° in the upper atmosphere. The space planes CoL is somewhat above the CoM creating a towing effect. Control surfaces may not overcome this effect in the normal way. Either use top engine thrust by disabling the lower ones to thrust the nose down (if fuel is still available)
  Or you pitch down first as much as you can then pitch up all the way to 90° and then push forward again to get to prograde. If you don't do this the nose will stay up and you will be stuck in the flat body stall until below 300m/s

 

 

Important

*If you use no mechjeb or any other autopilot you want to use pitch trim so the space plane wants to stay level. As speed increases the nose wants to pitch up in the thicker parts of the atmosphere so you want to adjust trim for this.
*In the upper atmosphere the CoT can be unbalanced with payloads that shift the CoM down. You can toggle on/off engines on the engine blocks with the action groups 2 through 6. This can be necessary if the weight of the cargo is further down when using a lower attached and/or wider shaped cargo. The combinations of action group 2 through 6 offers several dozen variations of engine setups. It's at your own leisure to find out the variety of engine combinations using a combination of action group 2 through 6 to be able to find the right balance. For most payloads the natural setup of all 96 engines should be centered so that you can maintain orientation up until the upper atmosphere in most cases. If your cargo's mass is hanging low though it is often better to find a better engine setup by toggling one, two or more sections on/off using the action group keys.
*Use mechjeb
*Stock SAS can be a bit wonky in the lower atmosphere due to natural pitching moment at higher speeds, the pitching moment can be to great under SAS input or very draggy cargo may succumb the pitching moment. If this happens there are 2 options. Firstly try to figure out which engine group to shut down using the action groups to re-balance the center of thrust at higher speeds to negate this effect in the upper atmosphere. If this happens in the lower atmosphere use action group 7 to toggle front spoilers for aerodynamic re-balance. If you do not remedy this when this occurrence occurs it can cause a RUD when pitching to great at higher speeds while carrying the heavier payloads at speeds above 500m/s. This shouldn't be troublesome as above 500m/s the rapiers have gained enough speed so that you do not need to have them running all at once. Above 10km you can turn all engines back on as the atmospheric stress is much less at this altitude and this problem shouldn't appear mostly.
*Know that it is important that you know how to attach your cargo properly.

Action groups.

1. Switches modes on all engines.
2 through 6. toggles different engines on either side for CoT rebalance.
RCS toggles the fuel cells to generate electric charge (if you need it)
7 Toggles front spoilers for aerodynamic rebalance past 400m/s (isn't necessarily required but depend on cargo drag and weight)

Facts:

Spoiler

 

• 78 Big-S Delta Wings
• 27 Big-S Spaceplane Tailfin.
• 2x Big-S Elevon 2
• Piloting using SAS is possible but not recommended. I insist you use Mechjeb Smart A.S.S. and use surface mode to hold 90° heading and at least 5° up to 8° pitch up at the end of the runway.
• Stay near sea level up to 450 m/s and then hold 4° or 5° pitch up but rise the nose degree per degree when using the heaviest payloads to avoid RUD. Stay on 5° all the way to closed cycle mode (with heaviest payload)
• Activate closed cycle at 20-23km (not higher) when going ~1600m/s depending on ascent profile with intention to climb or hold to at least ~150m/s climb rate and then hold prograde until apoapsis is at or above 70km altitude.
• 343 Parts without cargo.
• 96 rapier engines.
• ~120m/s takeoff speed using the heaviest cargo.
• MTOW: 2.750 Ton (2.75Kiloton)
• Can haul a max of 1450 Tons (1.45Kiloton) of cargo to orbit with spare fuel for landing. Most of the heavier spaceplanes do 500 to 1000ton
• At MTOW a rapier will carry 28.5 Ton each which is top record for engine efficiency.
• It has a very large payload fraction of up to 52.5% if piloted efficiently.
• Can carry a width of 12.5meters of cargo and up to a length of 65meters.
• It requires 1 pilot in the Mk1 cockpit.
• Can steer on the ground.
• Space plane can do water landing on empty weight when approach is slow enough ~55m/s.
• Empty weight landing speed is as low as 45 m/s
• Using the heaviest cargo the space plane can land on ksc terrain or the poles.
• Can land almost anywhere when empty.
• Due to the high mass and low drag co-efficient it can get up to ~1600m/s carrying the heaviest payload with a slight remainder of liquid fuel to spare for landing.
• It can aerobrake 90° through 45° pitch angle.
• If payload is heat protected and faired properly it can hold prograde while sinking to the Pe and sink down to 30km altitude without burning up.
• Can skip the atmosphere while holding prograde when going fast enough from a de-orbit burn due to wing incidence.
• Has good roll and yaw control during all phases of flight.
• Is evenly balanced in CoL, CoM in both wet/dry mass setup with or without payload attached. If the payload isn't super draggy it has a even natural pitch in all modes from liftoff until landing with a slight tendency to rise the nose.
• activating the brakes extends spoilers on all control surfaces to create drag at any layer in the atmosphere and is best used close to landing to fine tune landing speed without requiring you to turn. 
• The engine blocks are in the center for balance and have little to no gimbal effect. During the jet phase the control surfaces form the pitching moment. In the upper atmosphere or in space this effect is gone and depending on the height of the payload the space plane would want to go straight, pitch up, or pitch down. To combat that effect their are several action group modes 2 through 6 to toggle several engines on the 3 by 3 engine blocks to re-align the Center of Thrust up or down.
  This has very little impact on the performance as the required shutdown of the engines carrying any size of the heaviest payload has a sufficient tested engine mode. In all if not most cases the TWR is more then sufficient.
• Has enough Electric charge and reaction wheels to steer cargo into position in vacuum, do a retro maneuver after cargo jettison for de-orbit burn and then re-orientate to a proper aerobrake position with some leftover EC.
• Has fuel cells for electricity generation (RCS action group) Why on RCS: You do not use rcs on this spaceplane and if cargo used rcs it should be inside a fairing anyway.....
  If you don't like this function to be on the RCS action group you can change it to somewhere else. I chose RCS to free up the other numerical key action groups as people tend to like free room here on use with their cargo.
• Cargo has to be faired in most cases. This is more so for stability opposed to drag because this space plane easily break 400m/s at MTOW)
• Can carry 2 x 5 meter tanks next together or faired components in such form factor with room for wider attachments such as engines or asparagus tanks. Imagine a 2x5m rocket with 1.25m engine mounts sticking out.
• Cargo weight and cargo drag needs to be evenly distributed along the y, axis of the plane. That means the wider payload stacks needs to be evenly distributed in weight and drag as to not cause a unbalance. If you do not do this properly drag or weight unbalance can cause roll or yaw instability and consequential body and control surface drag in which case the performance may fall short or wont reach orbit or reach supersonic stage.
• Can survive 3 x physical timewarp almost always (4x in the upper atmosphere)
• Can carry another ssto or carry multiple ssto's. Additionally it could carry entire spacestation(s) or very large or heavy segments like interplanetary motherships or refueling stations.

 

Make sure payload is centered so that the Com is centered at the CoL.

Version 1 carrying a 7.5m wide center fairing.

Version 2 carrying 16 x S3-14400 3.75m tanks in parallel formation with a 50.5% payload fraction.

Version 3 carrying 2 x 5.5m(11m total) fairings next to one another. Make sure the payload across both sides is evenly matched. If your payload can't be distributed such way you should add dummy weight on one of either sides.

NOTE: I would be happy if people could point out complaints or ways to improve the vessel.

Happy flying

Edited April 2, 2019 by Aeroboi

[SG Aero]

Jesus! And I thought my several hundred ton lifter spaceplane was impressive!

[Aeroboi]

8 hours ago, ShadowGoat said:

Jesus! And I thought my several hundred ton lifter spaceplane was impressive!

Took me a while to get it done. It is a neat balancing act having tested various combinations for optimal efficiency. It's not something out of the sleeve

[Aeroboi]

Opening Thread updated!