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Iota and back again with the mighty Mousebat.

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It's going to take the nerds scientists a while to figure out all the data returned from this flyby, so in the meantime, the geeks engineers put together something that would keep the jocks pilots happy for a while. Nothing makes for a quiet life like getting people out of yours.

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2 hours ago, XB-70A said:

[...] Mortimer Kerman, who added that the cost of TWO Landing Struts is UNACCEPTABLE. We can not consider this flight as a success when our company has just lost 880 FUNDS on this mission that I would even define as USELESS.

[...]

Mission Successful, yes definitely! The Orbital Emergency Capsule I received its license of validity in the seconds that followed, this craft had demonstrated, once again, how wonderfully the unlimited capacities of the KSC engineers were, as well as their talent to spoil the time and the funds!

 

Yeah!  So shut up, Mortimer!  Or we'll send you on the next test flight!!!  =)

(I have also run out of likes for the day...)

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I've gotten a couple things done. A new, much more sophisticated GEO network is in place with synodic periods measured in millenia. These all used the Titan-Centaur booster: the satellite itself is almost absurdly small on top of the Centaur upper stage used for GTO insertion.

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The Bet 4 booster was tested, and found lacking. The primary issue is simply that the upper Centaur stage and core RD-108 stage are underpowered, resulting in excessively high pitch to maintain altitude. With a higher-thrust core, perhaps a 3-engine Centaur would have been enough; with a higher-thrust Centaur stage, perhaps the RD-108 core stage would have been enough, but both combined simply took too long to burn through their fuel.

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A competitor design has been proposed for the very important Voyager probes: the Gimel-2/4/6 series (yes, I'm now blatantly using the Hebrew alphabet in series). Each uses a quad-engine Centaur upper with a 6'30" burntime (as opposed to the 7'50" triple-engine Centaur of the Bet series), and 2-6 E-1 kerolox boosters. The primary difference is in the core stage, which replaces a single RD-108 kerolox engine with a pair of LR87 hydrolox engines, producing more thrust at a higher specific impulse than the old RD-108... unfortunately also at a much higher cost.

To be absolutely confident in the critical Voyager missions, coming up in five years, the first Gimel-4 mass demonstrator will use a 2.6-ton mass simulator, similar to the Voyager probes. If it cannot provide a 6.5 km/sec ejection burn after half an orbit, the Gimel-6, despite its 33,000-funds cost, will be used.

If I had a level 3 launchpad at KSC, I might try instead for just an even bigger mostly-kerolox booster to save on costs, but right now, I'm limited to 800 tons, which is just enough for either the Bet-6 or Gimel-6 boosters.

 

Past that, Mariner VI was sent on a mission to orbit Venus. While once again the S1.5400 second stage failed, there was enough margin in the Agena stage to not only finish the injection burn, but also have some left over for maneuvers all the way to Venus.

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I wish I had more screenshots.  I guess I didn't take nearly as many as I'd thought.

After delivering another science module to the station, the Reliant came down in what was thought to be a routine descent.  Nothing really went wrong, except they came up a bit short.  You'd think that by his 4th mission, Ferbert would know what he was doing.

Anyway, knowing there wasn't enough fuel to fly over the mountains west of the KSC, he put down in the very nicely flat plains near the base of the mountains.  The engineers scrambled at the KSC to devise the best rescue mission, which was to send a drone plane with a refueling cart.

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Paus got out to weld a refueling port to the tail of ship and hook up the cart.  (Tail refueling port is being attached to the entire fleet now.)

Luckily these shuttles were designed to be able to take off all by themselves.

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Typical landing at the KSC, despite Paus forgetting to repack the chutes while she was refueling.

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The tug went out and pulled it back off the runway to get parked behind the SPH.

A ship and her crew:

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Now I gotta see if that drone plane can come back.  No effort was put forth to design it that way... but it wasn't meant to land, either.  It was meant to pop the fairing and have the cart parachute down, but the first run resulted in the fairing deployment disintegrating the cart...

Hopefully in a couple missions I'll have a photo op of all 4 shuttles together.  Starting to wish I'd kept better records and attached an actual story to this...

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So, I said that if Gimel-4 reached 45 minutes in LEO with at least 6.5 km/sec left in the tanks, I'd use it, instead of the Gimel-6, to launch the Voyager probes.

It did.

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You may ask, "why is this so exciting that he would begin writing this post about a simple mass demonstrator mission a mere hour after his previous post?"

 

To understand this, we must first look to the performance of the first stage boosters.

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Just to the right of the delta-V panel, the panel with the red "E-1"? That means one of the four E-1 booster engines completely failed, with a substantial amount of propellant still left in that tank. Soyuz-Agena launches cannot survive such an event: the RD-107 boosters they use simply cannot gimbal enough to compensate for complete loss of thrust on one engine. This meant very difficult flying, as well as the depressing realization that I'd need to run another test just to be absolutely sure, and the time to the Grand Tour window is getting gobbled up.

Nevertheless, I perservered, jettisoning the now-deadweight booster.

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It was at about this point, igniting the Centaur final stage, that I realized it might just make it to orbit with enough delta-V to spare, despite losing a booster.

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Needless to say, the Gimel-4 booster has been authorized to carry the Voyager probes.

Though... let me double-check the NASA's Eyes program to double-check at what velocity the Voyager probes left Earth. Looks like 43 km/sec Sun-relative at Aug. 20, 1977, 10:33:42 AM, vs. 29.8 km/sec of Earth's relative velocity, so about 13 km/sec, which is pretty reasonable for a direct Earth-Jupiter injection. I think, then, the Voyager window doesn't require any weird higher-than-normal-energy Jupiter transfer.

Edited by Starman4308
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My space program is not in a good position right now and I'm salty about it.

I decided to double check something and I'm pretty sure now that being slightly in front of Duna means waiting a year before it's in good position to launch toward. So that's obnoxious. My only options at this point are to either fast forward (basically putting the entire space program on hold for a year, which the roleplayer in me loathes to do), try to do the mission now anyway and put Jeb in space for Kraken knows how many years (roleplayer in me hates this too), try to go to Eve instead, or attempt to keep myself busy for an in-game year (which is really not an option at this point). So I'm not happy about that.

In other news, I obtained the RAPIER engines and have concluded that they are the engine equivalent of a spork - it tries to be two things and is terrible at both. I made several attempts at building an SSTO with what I consider to be bare minimum parts for a worthwhile craft: cockpit, cargo bay full of science equipment (because what's the point if you can't do science?), a couple batteries and extendable solar panels I jammed into the remaining available cargo bay space (because I've learned my lesson about electricity from the last incident), small wings, tail and ailerons for atmospheric control, lightweight landing wheels, docking port (because I knew I'd need to be able to refuel in orbit), and some RCS valves so I could use said docking port. The only superfluous parts were the AIRBRAKES, which I was reluctant to lose because of the speed of this thing and I didn't fancy trying to land it without being able to slow down. Everything else was the RAPIER engines and fuel for them.

This plane was able to make it to 70km, and then promptly ran out of fuel before being able to circularize. Every time. I went through at least six iterations of the thing, and no matter what I did, I always ran out of fuel at 70km. Attempts to add more fuel defeated themselves by consuming more fuel due to the extra weight of the fuel.

Frustrated, I gave up on SSTO and tried launched the plane upright like a rocket using solid boosters in hopes of not having to waste precious fuel fighting the atmosphere.

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It still ran out of fuel before being able to circularize, because the RAPIERs are the most inefficient things imaginable. They're inefficient and heavy as jets, and they're inefficient and heavy as rockets, and I hate them with a blazing passion that is starting to leak over into my opinion of spaceplanes in general.

 

Me, bitter? Naw. Yes.

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So it turns out that if I drained my mini-station's on-board tank (which is mostly only used for running fuel cells, which are themselves only needed to run non-essential functions like the science lab and ISRU) I did have enough fuel to top up my Tylo landing craft. So without any further need for delay, I launched the landing attempt.

First, the craft was slowed to a sub-orbital arc by a tug.

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The tug then disconnected and burned prograde to put itself into a stable orbit so that it could be recovered later.

I then switched back to the lander, jettisoned its docking port and ignited its engines.

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After draining the side-tanks, they were discarded.

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Finally, the large lower fuel tank (and attached Poodle engine) was emptied and discarded, and the landing completed using the twin swivels on the main lifter unit.

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Touchdown!

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The mining/ISRU portion of the landing craft was the same design as my Eeloo outpost, and deploys its rover in the same way.

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With the rover deployed (and re-attached via docking port) pilot Tister Kerman and engineer Ronfurt Kerman left the lander to become the first Kerbals to walk on Tylo's surface.

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Here we have Tister taking the rover for a spin. It's a very different experience driving a rover on Tylo compared to the other airless bodies in KSP, as Tylo's high gravity means that the wheels rarely leave the ground.

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After using the mining and ISRU equipment to manufacture enough fuel to fill its tanks, the ascent module blasted off into orbit, which it was able to reach fairly easily.

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The unusual structure of the ascent module is because every component is meant to be re-usable. The small tank on the top is going to be returned to Kerbin for recovery; the module below it is a science module containing every scientific instrument available in the stock game and was already used to gather data from Pol; the main lifter is new for this mission but will also be used for Vall landings now that the Tylo landing is done; the two-person passenger module was also used for a Pol landing and will be used again on Vall and Bop, and the secondary tank on the bottom of the craft is the fuel transport tank used to ferry fuel from Foothold Base on Pol to Foothold Station in orbit.

The craft arrived safely at the mini-station in Tylo orbit, with enough fuel left over that I was able to re-activate the station's fuel cells and science lab.

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So that's one more landing completed, and the last landing in my career save that required some special engineering. The only bodies left to go are Bop, Vall and Eeloo, which should be much more routine.

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1 hour ago, Ace in Space said:

It still ran out of fuel before being able to circularize, because the RAPIERs are the most inefficient things imaginable. They're inefficient and heavy as jets, and they're inefficient and heavy as rockets, and I hate them with a blazing passion that is starting to leak over into my opinion of spaceplanes in general.

Any spaceplane needs proper engines configuration for better performancy, and elaborated flight profile. Rapiers is a good choice for lightweight spaceplanes (less than 20t wet mass, or something), for good drag-optimized spaceplanes, and good for combination with another engines.

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2 hours ago, Ace in Space said:

decided to double check something and I'm pretty sure now that being slightly in front of Duna means waiting a year before it's in good position to launch toward. So that's obnoxious. My only options at this point are to either fast forward (basically putting the entire space program on hold for a year, which the roleplayer in me loathes to do), try to do the mission now anyway and put Jeb in space for Kraken knows how many years (roleplayer in me hates this too), try to go to Eve instead, or attempt to keep myself busy for an in-game year (which is really not an option at this point). So I'm not happy about that.

Eyeballing interplanetary transfer windows is... not easy. If on top of that you're adding roleplaying (i.e., no fast-forwarding another few years), that makes it even more difficult.

I would suggest you check out alexmoon's transfer window planner, and lay out your mission schedule in advance with that. (I just fast-forward when necessary, I only roleplay when I feel like doing something else in the interim.)

https://alexmoon.github.io/ksp/

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2 hours ago, Ace in Space said:

<Cut for length>

SSTOs are the most difficult type of craft that you can make in KSP. It personally took me many attempts before I made one that could even get into orbit. However when done correctly they are FAR more efficient than traditional rockets. There are two very important details about SSTOs that you really need to know. One is that the balance between liquid fuel and rocket fuel tanks needs to be precise, this may seem obvious but it's importance cannot be underestimated, too much of either one can leave you with a lot of excess liquid fuel or oxidizer which will greatly decrease the delta-V of your craft, you should have more rocket fuel tanks than liquid fuel and the exact proportion can really only be determined using experimentation. Secondly is the flight profile, a good flight profile can make or break an SSTO. A good rule of thumb is that a good flight profile should require minimal user input to minimize speed loss to maneuvering, most of the acceleration should be done outside of the lower atmosphere (above 7 kilometers), and in general the SSTO should reach atleast 1500 m/s while the R.A.P.I.E.R.s are still in jet mode. These speeds are simply not possible using any other type of jet engine, hence why very few SSTOs incorporate a significant amount of any other type of jet engine. An SSTO of that size should be able to deliver a payload around a fifth it's own mass, however the exact proportion will vary. Experimentation is key, the only way you can fix an SSTO is by flying it over and over again until you work out the kinks, I have NEVER built an SSTO to this day that worked on the first try. Hope this was helpful!

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2 minutes ago, Brikoleur said:

Eyeballing interplanetary transfer windows is... not easy. If on top of that you're adding roleplaying (i.e., no fast-forwarding another few years), that makes it even more difficult.

I'm not hardcore roleplaying this, so I'm a bit reluctant, but in the end, I'll probably end up begrudgingly using time warp. I'll just be a little bit grouchy about it. :P But thanks for the link.

Truth be told it's just that I'm still new and clueless. Also in a bit of shock because I thought I'd gotten over the steep part of the KSP learning curve - turns out it's multi-tiered.

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1 minute ago, Kronus_Aerospace said:

One is that the balance between liquid fuel and rocket fuel tanks needs to be precise

I actually got them pretty well balanced - I just ended up running out of both when I hit 70km. The rest of your information was helpful, though. I think the main problem is just that, as stated above, I have no idea what I'm doing. I probably just need to do some research. That's typically how my KSP experience has gone so far: try to learn by trial and error experimentation, fail, give up and go on a youtube binge until I have some fraction of an idea what I'm doing.

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1 hour ago, Kronus_Aerospace said:

and in general the SSTO should reach atleast 1500 m/s while the R.A.P.I.E.R.s are still in jet mode

Otherwise excellent explanation, but I'll quibble with this one. I think it's true for some designs -- specifically, extremely aerodynamically efficient ones -- but I think "at least 1500" is too ambitious a target for most planes where you might have to make aerodynamic compromises in order to get the plane to perform its mission, e.g. hauling up cargo.

Accelerating to 1500 with RAPIERs means that either you're packing a ton of them, or that you're on a very flat trajectory. The latter is not good because you'll be spending much longer than you'd need in the upper atmosphere, and drag at 20-45k is still very much a factor.  So when my jets flame out I'd rather be going 1300 in a healthy climb than 1500 straight and level, whereas 1500 and climbing means I've overbuilt my plane.

So I would say, "in general the SSTO should reach 1200-1400 while the RAPIERs are still in jet mode."

In a bit more detail, here's the ascent profile I generally target -- individual planes may vary, especially in the first phase where I might need to build up some speed/TWR to get into a healthy climb/acceleration:

  1. After take-off, build up enough speed in a shallow climb that TWR starts going up and is high enough to keep you accelerating in a steep climb. Then climb at 30-45 degrees. Target is 360-400 m/s at 5k.
  2. At 5k, nose down to 17-20 degrees. Minimal control input should be needed from here on out.
  3. At 10k, I should be going about 700 to 1000 m/s, still at 17-20 degrees pitch, with the attitude and vector perfectly aligned, or as close as, and should be accelerating rapidly. The nose will very gradually come down as I climb.
  4. At 25k or so, jets flame out. I should be going at 1200-1400 m/s, with Ap around 33-38k 1 minute or more ahead, vector maybe 5 degrees over the horizon.  
  5. Go surface prograde, switch to rockets on full power and burn until Ap hits my target (usually 75-80k).
  6. Follow surface prograde and coast to Ap, then circularise.

It's probably not perfect but I have experimented with shallower/faster profiles, and I do find this to be more efficient than they are. Targeting speeds over 1400 probably means I've overbuilt the plane (i.e., am burning fuel hauling up mass I don't need) or am going on too flat a trajectory (i.e., am burning fuel fighting atmospheric drag).

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4 hours ago, Ace in Space said:

This plane was able to make it to 70km, and then promptly ran out of fuel before being able to circularize. Every time. I went through at least six iterations of the thing, and no matter what I did, I always ran out of fuel at 70km. Attempts to add more fuel defeated themselves by consuming more fuel due to the extra weight of the fuel.

I think others have given you some good feedback above, but I'll add that to my eyes, this SSTO has very little wing, and very little fuel. While this can be made to work, it must be flown perfectly, and you don't sound like you have any experience with spaceplanes. Here's a bird of similar size I made a while back for comparison. I'm pretty sure it has more fuel, more lifting surface, and half the TWR - but it flies to orbit. Making rapiers work is very much about the flight profile; if you're having to maintain a high angle of attack (pointing the nose more than ~8 degrees from prograde) in the low atmosphere, you're going to have a problem later.

Spoiler

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But this was quite hard to build, even after months years of spaceplaning. A standard starting point would be 2x rapier, 1x LV-N, which gives you both atmospheric efficiency, high on-air top speed, an LF+O kick to get to apoapsis, then a high efficiency engine for orbital insertion. The rapier rocket mode is best used to get out of the atmosphere, and then disabled, because indeed it is an inefficient rocket engine. I'd recommend a browse around this thread to see how other people build spaceplanes, because it's definitely a learning curve, but very satisfying once you crack it :)

 

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4 hours ago, Ace in Space said:

In other news, I obtained the RAPIER engines and have concluded that they are the engine equivalent of a spork - it tries to be two things and is terrible at both. I made several attempts at building an SSTO with what I consider to be bare minimum parts for a worthwhile craft: cockpit, cargo bay full of science equipment (because what's the point if you can't do science?), a couple batteries and extendable solar panels I jammed into the remaining available cargo bay space (because I've learned my lesson about electricity from the last incident), small wings, tail and ailerons for atmospheric control, lightweight landing wheels, docking port (because I knew I'd need to be able to refuel in orbit), and some RCS valves so I could use said docking port. The only superfluous parts were the AIRBRAKES, which I was reluctant to lose because of the speed of this thing and I didn't fancy trying to land it without being able to slow down. Everything else was the RAPIER engines and fuel for them.

RAPIERs are brilliant. They're the best high-altitude/high-velocity jets in the game (Whiplashes are better at slightly lower speeds, but RAPIERs keep pushing past their ceiling), and while they're somewhat inefficient rockets, they're still far more efficient than having to haul up dedicated rocket engines for the job. I just tried making an "export version" of the Pelican 2 yesterday, and with six Whiplashes and 2 Reliants it does squeak into orbit, but it doesn't cruise there like on eight RAPIERs.

I.e. your problem isn't with the propulsion: it's with the general design of the thing. Spaceplanes are hard because aerodynamics are hard. If you're only just getting into them, I'd suggest dropping all those sciencey and electric and docking and RCS bits and just focusing on something that gets to orbit no problem, then start adding stuff. 

Tip: when under development, use extra fuel tanks as payload. They'll provide what you need to get to orbit, you can use their contents as ballast to control attitude on re-entry tests, and you'll be easily able to see what your Lf/Ox balance is once in orbit. They're also really useful to gauge your lifting capacity: just read how much Lf/Ox you have when you reach orbit, convert to kilograms, and presto, that's your maximum payload mass.

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5 hours ago, Ace in Space said:

In other news, I obtained the RAPIER engines and have concluded that they are the engine equivalent of a spork - it tries to be two things and is terrible at both. I made several attempts at building an SSTO with what I consider to be bare minimum parts for a worthwhile craft: cockpit, cargo bay full of science equipment (because what's the point if you can't do science?), a couple batteries and extendable solar panels I jammed into the remaining available cargo bay space (because I've learned my lesson about electricity from the last incident), small wings, tail and ailerons for atmospheric control, lightweight landing wheels, docking port (because I knew I'd need to be able to refuel in orbit), and some RCS valves so I could use said docking port. The only superfluous parts were the AIRBRAKES, which I was reluctant to lose because of the speed of this thing and I didn't fancy trying to land it without being able to slow down. Everything else was the RAPIER engines and fuel for them.

This plane was able to make it to 70km, and then promptly ran out of fuel before being able to circularize. Every time. I went through at least six iterations of the thing, and no matter what I did, I always ran out of fuel at 70km. Attempts to add more fuel defeated themselves by consuming more fuel due to the extra weight of the fuel.

Frustrated, I gave up on SSTO and tried launched the plane upright like a rocket using solid boosters in hopes of not having to waste precious fuel fighting the atmosphere.

It still ran out of fuel before being able to circularize, because the RAPIERs are the most inefficient things imaginable. They're inefficient and heavy as jets, and they're inefficient and heavy as rockets, and I hate them with a blazing passion that is starting to leak over into my opinion of spaceplanes in general.

Me, bitter? Naw. Yes.

Oh boy do you need to rethink your views on Rapiers. Rapiers are not "terrible at both".

#1,) They are not great as rockets, but they are hands down the best jet engine for high altitude and high speed flight. They have a higher maximum speed than Whiplashes, they have a higher maximum airbreathing altitude than whiplashes. Sure they consume 25% more liquid fuel for the same amount of thrust, but the fuel consumed in airbreathing mode is a small fraction of total fuel consumption (this becomes even more true if you play with a scaled up Kerbin). If you get to 30km at 1550 m/s vs 1350 at 27 km, you're going to use less fuel overall when you switch to rockets. Rapiers use 1/10th the fuel per unit thrust compared to a Swivel or Skipper. That extra 200 m/s of airbreathing speed is essentially "free" (or at least comes at a 90% discount).

#2) They aren't terrible as rockets, they aren't great, but they beat any radially mounted rocket engine. Lets go back to comparing "max" airbreathing speeds of whiplashes and rapiers, 1350 and 1550 roughly. After this, you need to supply roughly 800 m/s with rapiers, or 1000 m/s if you used whiplashes. Consider the Rapier vs an aerospike+whiplash combo. As for rocket performance, we're comparing 305 Isp to generate 800 m/s vs 340 Isp to generate 1000 m/s. With the fuel it takes to generate 1,000 m/s at 340 Isp, you could generate 100*305/340 = 897 m/s at 305 Isp... but... 1x Whiplash + 1x aerospike masses 2.8 tons, the rapier only masses 2 tons. Even at a 2:1 whiplash to aerospike ratio, the "mass per jet engine" is then 2.3 tons, and you have half the rocket TWR... 

Is it still looking so terrible? but wait, there's more:

Adding inline rocket engines (assuming a 1:1 ratio) basically doubles your frontal area (assuming no part clipping exploits here), increasing drag and complicating designs. Your craft will be more massive with more drag, just to save on airbreathing fuel consumption, which is a minor portion of your fuel consumption anyway.

IIRC, the spaceplanes that achieved 50% payload fraction in payload fraction challenges were rapier only.

This thing will deliver payloads to Mun orbit:

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This thing will deliver massive payloads to LKO:

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Spoiler

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^That things payload docked with this things payload, they are both outdates designs, but this next one is moreso because one of the versions changed the heating enough that those big wings won't survive reentry.

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3 hours ago, Ajiko said:

Any spaceplane needs proper engines configuration for better performancy, and elaborated flight profile. Rapiers is a good choice for lightweight spaceplanes (less than 20t wet mass, or something), for good drag-optimized spaceplanes, and good for combination with another engines.

In the end, for stock KSP, and just getting to orbit, I found all rapier designs to be what I want. Trying to get better performance out of a mixture of engines wasn't worth the effort.

Playing a 3x rescale (1.25x atmo rescale, because the stock atmo is already pretty thick), I find that a combination with nukes is good. I managed to get a rapier + LV-N design up to a 17% payload fraction (not including fairing mass), and a rapier only design (with a mk3 cargobay) to a 7% payload fraction (not including the mk3 bay mass, which actually is significant)

Spoiler

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^ That got a 7% payload fraction

This got a 17%

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An earlier design for 3x got ~10-13%, I forget exactly

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This thing, if it was in stock KSP, would easily be delivering 100 ton payloads to Minmus orbit.

btw those last two, there is a rear-section which redocks, in 3x its really important to minmize frontal area, because drag losses are enourmous when trying to accelerate to orbit lower in the atmosphere, from 1550 surface to ~4100 m/s orbital velocity (IIRc its about 3,600 m/s surface)

Here's a test of an "empty" config with just a tiny amount of LF in the tanks at the empty CoM for test flying it:

pwGZcTU.png

 

 

 

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Damn.... No screenshots. I guess I pressed Shift-F1 slightly wrong (damn Windows hotkeys, whenever I press F1 it googles 'how to get help in windows 10.)

Well, whatever, I'm sure I can describe it just about good enough for you to see it in your head. Today (actually yesterday) I launched STS-1, the first shuttle to carry crew. We managed to get to orbit just fine,  and warped round into daylight to deploy the KerboSat 1 payload. Here's when I noticed something weird. On UTP-2, we carried a 19-ton payload into orbit and still had about 350m/s of delta-V remaining, probably enough to perform a rendezvous. But on STS-1, we carried a three and a half ton payload into orbit and only had about 50 m/s remaining. Might be a glitch with Kerbal Engineer.

Luckily, once we released the satellite, our delta-V grew to 506m/s. The satellite's booster stage, supposed to get it into a higher orbit, had 4 kilometres per second of delta-V. I could probably send it to Duna or something. Once the satellite had got to its 700km orbit, I positioned it towards the planet to start its 'scanning'. Rather than release the booster stage, I elected to leave it attached, as it could be used for orbital manoevring. Wouldn't want to waste that sweet, sweet delta-V, would we?

After that, I switched back to the shuttle to see how they were doing. They seemed happy, and Kelzor even went out on EVA. Then I checked up on the external tank. It re-entered the atmosphere after only one pass, and the re-entry heat was so intense that it blew up the forward tank. Eventually the tank splashed into the ocean and was completely destroyed.

Leaving our brave kerbonauts in orbit, I went back to KSC to have a bit of fun flying one of my planes around. Behold... the Planey Plane Mk3!

PDN7bw5.pngThis pic isn't from today, but I just wanted to show you this thing. It's incredibly stable, does all the stunts you want, and can break the sound barrier easily. But I have found a way to trip it up!

Simply pull up into a steep climb, then press Q or E to roll. It starts to tumble and spin! If you're high enough, you can pull up and start flying normally again.

8DGn9W7.pngHave a pic of my Concorde replica as well, because why not.

Bye for now!

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17 hours ago, LordFerret said:

move this save (v1.2.2) over to v1.3.1 ??

It worked for me anyway.  The major trick is to upgrade all your mods first to 1.3.1-compatible versions or do without them.  Frankly, I waited until my puny number of mods were all available before I bothered to try the upgrade.

Edited by Hotel26
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I'll start by saying that I took, not one, but two joyrides in @Brikoleur's Pelican 2 last night.  On the second ride, I just had to do a barrel roll during the circularization burn.  Great stuff, that Pelican.

Afterward, a few drinks in a bar a few blocks from KSC and I overheard a conversation in the next booth intimating that, as of 2019, Kerbal Space Command will be tightening the eligibility rules for promotion to Star Fleet Kommander: only pilots who have checked out in the new Gossamer Albatross will be considered.  Well, what do you know??!

But the main project of this current 24-hour cycle has been a top-secret mission.  I can maybe divulge a single screenshot discreetly and let you figure out what you need to know is coming REAL SOON...

uLamiDM.png

"Jumping The Moon"

 

Edited by Hotel26
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3 hours ago, Brikoleur said:

Otherwise excellent explanation, but I'll quibble with this one. I think it's true for some designs -- specifically, extremely aerodynamically efficient ones -- 

Well in general I try to make all of my SSTO'S as aerodynamically efficient as possible, and they never require particularly flat trajectories to reach such velocities, My SSTO'S usually have a thrust to weight of around .6, and are more likely to dip below that number than above it, although it is true that this does not apply to all SSTO'S, especially SSTO'S with drag issues as it is more efficient in that case to take slower but more steep flight Profile. I think 1200 m/s is rather low considering that is well below the maximum operating potential if the R.A.P.I.E.R.s, a fairer estimate in my opinion would be 1400-1500 m/s, having built innumerous interplanetary capable SSTOs I have done much experimentation with flight profiles and I find that those numbers work the best.

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2 hours ago, KerikBalm said:

If you get to 30km at 1550 m/s vs 1350 at 27 km

You are mistaken, 1450-1470 can be reached with Whiplashes easily, it depends from aerodinamics and flight profile.

I think it needed to reconsider some common beliefs about spaceplanes effectiveness.

Payload mass - means nothing (I think, you understand why). Payload fraction - means nothing (deliver 30% payload fraction to orbit with start wet mass of 30t much more heavy, than even task on 300t-wet-mass-monster, at first because for 300t monster you can did proper engines configuration). Next thing a bit heretical - "LKO dV" means nothing (at this point some peoples pull out their rotten eggs for me, I know).

I think its better to use for spaceplanes more universal efficiency marker - ratio between LKO dV and craft fuel mass fraction ((LKO dV) / (craft fuel mass fraction)). It removes the difference in the graduation between cargo-sstos and passenger-sstos for example, for heavy-sstos and lightweight "birds".

Try to graduate your crafts by this indicator. Maybe you find something interesting?

Edited by Ajiko
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