SABR3 Sterling v0.4.0 Pre-release [KSP 1.7.x] [Apr 24, 2019]

[Redacted]

I'll try doing the next flight without tanks that jettison. Will keep the Tanks attached but inside the intercoolers. (lol, my spell check keeps trying to correct intercooler to intercourse)

Edited April 4, 2019 by Redacted

[Redacted]

Here is a link to the MK3  SSTO without the jettisonable tanks.

https://steamcommunity.com/sharedfiles/filedetails/?id=1702794482

 

Two small things I've noticed...

-The Saber intercoolers are gray while the in development craft they’re flat black. Would it be possible to offer flat black as an in game option?

-The thrust effects between the Advent and President turno-jets each have their own colors. This looks strange especially when both are using the same kerosene RP-1 “liquid” fuel. Far as i know of, RP-1 should burn yellow / orange, depending on how rich / lean the fuels are mixed.

Edited April 4, 2019 by Redacted

[JadeOfMaar]

@Redacted It looks alright without the drop tanks. Of course, it can't be called SSTO if it decouples anything at all from itself like the wheels too. A black variant is actually a great idea, especially since Restock happened.

[Redacted]

The real life Saber passed its bench test for the precooler today!

https://edition.cnn.com/travel/article/air-breathing-rocket-scli-intl-gbr-scn/index.html

[Redacted]

Justa  heads up...

The Engines appear to be separating from the intercoolers, causing a chain reaction that can destroy the craft.

Here is a pic of the chain of destruction as per KSP. IF it doesnt show here, then just open via another tab.

Video of the flight: 

 

Edited April 12, 2019 by Redacted

[Redacted]

From what i can tell, this problem is only with the curved intercooler not the straight.

 

Edit: Does the "curved" intercoolers facing (direction of the curve) make a difference in the way force is applied to it?

 

Edited April 12, 2019 by Redacted

[JadeOfMaar]

@Redacted Lol. If it means anything, you should be showing KER's VESSEL panel. Your data is missing the acceleration and max gee values. What I can safely assume is that your aerodynamic load was unreal and you hit a critical point between that, engine gimbal, and the shock cones producing angled lift or drag due to being attached on the curved intercooler... But why the engines are the first to break off is beyond my reasoning. Perhaps they needed to autostrut too, if you didn't already, and depending on your craft, they likely need to autostrut.

[Redacted]

A few things i forgot to mention.

- Auto struts were enabled.

-Motor gimblas for the exterior motors were locked.

-Straight intercoolers dont have this issue. Same craft, swapping the intercoolers solved the problem. after swapping back problem returned.

Edit: Only thing I have not tried was to limit the motor thrust for the side mounts. Then again, to do so would negate the whole point of having them. Still I’m thinking that the curved mounts are deflecting the airflow in a direction thats placing a huge amount of aerodynamic stress directly on the motor. Which is why i asked if they were intended to be used in a specific facing, thus controlling the aerodynamic stresses in a predictable way.

Edited April 13, 2019 by Redacted

[Redacted]

Question: What factors determine the rate at which O2 is generated? Far as i can tell, once the craft is at the prerequisite speed (> 800 ms) the O2 rate is fixed. Seems like the only way to improve it would be to add more intercoolers.

Edited April 14, 2019 by Redacted

[JadeOfMaar]

@Redacted Oxidizer production rate varies with these things:

1. Mill Power. The intake rate for this (in the intercooler) changes between Mach 2 and Mach 5. Its availability at a given time varies with demand by the intercooler until the supply exceeds demand.
2. IntakeAir availability. By design, the generator hoards IntakeAir and can threaten to starve jet engines. The reason the intercoolers hold so much air is: To buffer the air supply waiting to be cooled/converted. Skylon is supposed to need only carry a small fraction of its total needed Oxidizer. This buffer attempts to simulate that.
3. All intake rates scale with atmosphere pressure so as you approach vacuum, the intakes of Mill Power and IntakeAir will dwindle, causing demand by the engines to eventually exceed the supply.

 

On 4/12/2019 at 5:01 PM, Redacted said:

A few things i forgot to mention.

- Auto struts were enabled.

-Motor gimblas for the exterior motors were locked.

-Straight intercoolers dont have this issue. Same craft, swapping the intercoolers solved the problem. after swapping back problem returned.

Edit: Only thing I have not tried was to limit the motor thrust for the side mounts. Then again, to do so would negate the whole point of having them. Still I’m thinking that the curved mounts are deflecting the airflow in a direction thats placing a huge amount of aerodynamic stress directly on the motor. Which is why i asked if they were intended to be used in a specific facing, thus controlling the aerodynamic stresses in a predictable way.

I don't know what to tell you about that. I assumed the same, that is, angular aero force from the shock cones on the curved intercoolers threaten your craft. Concerning orientation, you had them placed wrongly if you're paying any attention to realism and practicality. The idea of the curved nacelle is that the shock cone hangs down so that when the craft is nosed up, the shock cone is directly aligned to the air stream meanwhile the engine fires downward to provide up-force and aid in the ascend. Beyond that, I'll repeat that you possibly had too much TWR and too much blunt surface area due to having a very wide and thick plane.

[Redacted]

Today i did a basic test as on the DS Curved Intercooler. What I did was mount a Curved unit on one side vs a Straight on the other. (Advents) Beyond that the aircraft was very basic, using only was was needed to achieve stable flight. The differences in drag were later noted between each side. Overall the drag figures for the engines and intercoolers were comparable. Yet the drag from shock-cone of the Curved unit was three times that of the Strait unit in level flight. Obviously this is due to the cone coming in at an oblique angle, while the rest of the craft is facing prograde. It's this difference that thats over-stressing the entire assembly in flight.

Note: Curved side was with shock one facing downwards.

While i understand the basic idea behind the curved mount is to have the cone facing prograde while the craft is flown at a fixed angle. However this is not how SSTO's are flown in KSP or at least not what I've seen from numerous video's. Ideally players ride up on a long shallow assent path to minimize the drag / heating of the crafts body. Yet this comes into conflict with curved mount, creating excessive drag and the destruction of the entire motor assembly.

Question: Have you flown the curved mounts recently?

 

[JadeOfMaar]

@Redacted Yeah I expected drag to be deadly in your setup. I don't think anyone who uses the curved intercooler would have your problem. It's been quite some time since I used any curved ones myself, rightly because that's just not a thing with SSTOs in KSP (and related, I believe the engine itself is or should be angled down IRL, not the intake, or both are angled down). But when I did I had no worries about drag because I don't build my SSTOs to have self-destroying TWR. SABR3 really shines in that kind of ascent profile in opposition to my normal steep climb then level flight at high altitude for other air-breathing engines. 10 or 20 deg are really nice for it.

[JadeOfMaar]

Pre-release 0.4

• Finished existing heat emissive textures.
• Added heat emissive to all engines.
• Enabled cryoengine patch.
• Upgrades now available to air-breathing and closed-cycle in all engines except SCIMITAR Advent.
• Adjusted drag cubes in cowls.
• Changed plumes again.
• Added spec map to main textures for engines.

Full release should come in mid-May? The install path for this will change then. Engine behavior might change a bit too.

[Redacted]

Downloaded and will report back.

[Redacted]

Ok gave it a run.... Rather like the switch to H2 as this makes it much easier to pair up the Saber with small nukes for orbital maneuvers. Haven't tried the curved yet as I'm still tinkering with an Mk3 design.

[Redacted]

The the redesigned MK3 is great!

 

[Redacted]

Just a little something i have been using. If done right I can boost a rather large payload beyond 11,000 km and still make it back for the boosters splashdown.

 

[Redacted]

Here is a crazy SSTO using the Shock-Cone and Aero-RCS thrusters. This little thing can reach 1800 ms in an atmosphere before kicking on the NERV for the final boost!

 

[JadeOfMaar]

Dark Mode is finally done. Except for a few obvious glaring faults.

[MaeharaProjekt]

Wow. I love how these are coming along. 

[Redacted]

Any chance of both the engines getting a performance boost ?

Side Note: Been messing around allot with ASC (atmospheric control system) RCS thrusters. I've an MK3 SSTO that can make it past 70km before needing nukes for circulation. 

[JadeOfMaar]

@Redacted Define "both" engines. At the very basic there are three: the two sizes of SABRE and the SCIMITAR airliner engine. But I bet you mean the two SABREs. And no, I have no plans for a perf boost.

[Redacted]

I've been using the Broadsword engines recently. Part of why is not just performance but it's use of liquid fuel. Makes it much easier to design an SSTO that uses nukes in orbit.