Kerbal Transportation System, MkV. The most accurate STS replica I've done!

[Rune]

Yeah, I promised you Christmas presents. Why not a Shuttle replica? Mind you, this is either a craft for seasoned kerbals... or for kerbals that want to learn their stuff the hard way. I salute those who try! Just like the real thing, this is a very demanding ship with little room for error.

Even among the throng of STS replicas out there, I'm still quite pleased with how this turned out. It is moderately useful, and it looks totally like the real thing. And it works like a charm, too! I might write up a couple of flight indications, but really, if you have gotten any other shuttle to orbit, you should manage this one without issues just by remembering to toggle the RCS on on launch. Oh, and it is my usual ridiculously low number of pars, 155 on the pad with the reference 11 part payload, plus it brings half the orbiter's weight up, 20mT (not down, though, it has severe mass limitations for a safe landing).

So, the little details that make it an extremely accurate replica:

-Obviously, it has the same stack as the real thing: an engine-less Extrenal Tank, surrounded by two SRBs (no liquid boosters!) and the Orbiter with the three main engines feeding off the ET.

-A thrust profile for the SRBs. You can tweak it further if you vary the payload, but right now the SRBs vary the thrust during flight, halving it once before the final cutoff. It works just enough to keep the torque in check, forcing the gravity turn actually. Just try to keep it upright facing the right way, and if you panic in the end when you start tilting anyway, just let the SRBs go, you have the margin and it's safe, besides looking pretty. You can ride them until they run out, though.

-Payload is a low-density twenty tons, in this case that half-full orange tank. This is not only accurate to the original, it means this is my first useful shuttle replica. Well that was unexpected.

-A OMS system that runs on different fuel mixture (monopropellant in this case). I know it doesn't look like it, but those Mk55's are there for looks only, they hide the true monoprop engines and simulate their mass. Remember to un-forbid the rear monoprop tank when you turn them on, it's cut off initially so the RCS subsystem doesn't use it during ascent.

-No power generation on the orbiter other than the SSME's alternators (useless in space), so the mission time is constrained by that unless you dock to a station. That is an intentional feature, yes.

-It glides just like the real thing: not very well. Though you have adequate crossrange to line up the runway, you'd better come out of reentry with KSC in sight, and the stable gliding speed is just not survivable on touchdown: you have to save some energy and flare up at the last second to bring the descent speed under a safe 5m/s for the touchdown. And careful with high angles of attack, you can perfectly fine stall it to death on the final approach (ok, I know it's not a true stall because KSP aerodynamics, but it looks like one). Have fun trying, and don't forget to quicksave on final approach!

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Rune. Covering "the basics".

[FishInferno]

Bravo, good sir, bravo!

[pTrevTrevs]

Finally! I have been looking for a good shuttle replica to use. I wonder though, would it be possible to convert this into a Buran type ship?

[Tangle]

Finally! I have been looking for a good shuttle replica to use. I wonder though, would it be possible to convert this into a Buran type ship?

It already looks pretty much like it on the SRB front, so...

[AppleDavidJeans]

...

You just made me make a mess in the seat of my pants.

[Rune]

Bravo, good sir, bravo!

Thanks!

Finally! I have been looking for a good shuttle replica to use. I wonder though, would it be possible to convert this into a Buran type ship?

Not the way it's built! I would have to completely change the boattail to put LFO inside, CoM would change since the orbiter would have much less empty weight on account of lighter engines, and of course the boosters would have to be redone entirely and the stack rebalanced. And I'm pretty happy with how the SRB auto-throttle turned out. Anyhow, the main thing is it would be almost as difficult as a from-scratch build. Might do that anyhow.

It already looks pretty much like it on the SRB front, so...

¿Wait, what? Having SRBs is pretty much not a Buran thing... Incidentally, did any of you guys actually tried the thing? If so, what did you guys think about the last seconds before SRB burnout? I'0m rather curious to see what people think of the handling

...

You just made me make a mess in the seat of my pants.

Oh dear, I hope that was in a good way!

Rune. I know I can fly it. But can you?

[pTrevTrevs]

Incidentally, did any of you guys actually tried the thing? If so, what did you guys think about the last seconds before SRB burnout? I'0m rather curious to see what people think of the handling

I was able to launch it easily enough, but flying down to a landing was horrible! The first time I tried it, I overshot KSC and crashed in the ocean out beyond the island airbase. The second time, I barely made it over the mountains and crashed in the plains between KSC and the mountains. You weren't kidding when you said it didn't glide very well! It quickly lost most of its lateral velocity and just fell straight down. Any attempts I made to pull out of the dive resulted in an unrecoverable flat spin.

[Naito]

I like how you did your engines. Gonna borrow that for my shuttle =)

Mine glides well in both FAR and stock though(almost too well, if it flew more like a brick I'd be happier with the accuracy lol), how's your CG look like?

[Rune]

I was able to launch it easily enough, but flying down to a landing was horrible! The first time I tried it, I overshot KSC and crashed in the ocean out beyond the island airbase. The second time, I barely made it over the mountains and crashed in the plains between KSC and the mountains. You weren't kidding when you said it didn't glide very well! It quickly lost most of its lateral velocity and just fell straight down. Any attempts I made to pull out of the dive resulted in an unrecoverable flat spin.

Just like the real thing! Yeah, I also did a flat spin on the test flight, but if you know why and how it's happening, have a lot of practise flying simulators, or have a lot of luck, you can pull it out of it and still level before you hit the ground. It's very difficult to explain because I mostly do it by gut feeling and practice, but it involves a lot of roll control while bringing the nose close to prograde. You can maintain about 20-30º degrees of angle of attack over your velocity vector before you loose it completely (emptying all fuel tanks except the one on the cockpit helps). That behaviour, BTW, is inherent from the configuration of the shuttle, that low wing with no dihedral is just unstable by nature, and the big stabilizer can only help so much without creating its own issues, being so far back.

The really interesting thing comes after you are on a steep and stable glide slope: there's not really enough wing to glide, so at most you fall with style (the prograde vector will be in the brown the whole way down). And if you arrest your vertical speed to under 10m/s, something only possible at about sea level BTW, the horizontal speed drops and you start falling again. So the flare the real shuttle has to do to touch down at a safe vertical speed after saving some kinetic energy to pull that off? That is required, besides a sea level landing to get the highest atmospheric density possible. Basically, keep her falling at about 70m/s, and pull up at the last second to turn some of that energy into vertical deceleration and bring vertical speed to just below 5m/s just before landing. Takes a bit of practice, but it's totally doable, and a good learning experience. Quicksave on final approach!

I like how you did your engines. Gonna borrow that for my shuttle =)

Mine glides well in both FAR and stock though(almost too well, if it flew more like a brick I'd be happier with the accuracy lol), how's your CG look like?

I'm glad you do! It's a lot of dead weight, but it is very light on parts, and looks good on small MkIII orbiters. I don't think I have a pic handy showing CoM/CoL, but I remember it being a fair way forwards of CoM and slightly under it (that last part is not good, but it's a shuttle thing). That is, if the rear mono tank is empty and the bay too. If not, you are not going to be able to stop in time to meet the ground without a bang anyway, so...

Rune. If there are a few petitions, I might do an easy unrealistic version with more wing and bigger margins and stuff like that.

Edited January 2, 2015 by Rune

[pTrevTrevs]

Hmm, maybe I'll try and put the orbiter on top of a plane and practice landing like NASA did with the Approach and Landing Tests.

[longbyte1]

No back parachutes?

[Rune]

Hmm, maybe I'll try and put the orbiter on top of a plane and practice landing like NASA did with the Approach and Landing Tests.

That would be very cool to see! Post pics if you attempt it!

No back parachutes?

Well, that was only added after Challenger, and my ET is white, so... I am just going to say that this is a replica of STS-1, and walk away from a fumble like nothing happened.

Rune. Geekiness to the rescue!

[pTrevTrevs]

I was considering using RealChute to fit a drag parachute on the back, but I haven't had a chance to try it yet.

[Mesklin]

It is really great work, tricky ascent, tricky landing, as in real life. And, if you slightly move wing to the forward, it is greatly increased flight possibilities of your shuttle. Like on pictures:

[Naito]

Hmm, maybe I'll try and put the orbiter on top of a plane and practice landing like NASA did with the Approach and Landing Tests.

That's kinda what I did when I was designing my orbiter =p

FYI it flew, but not very well. I ended up designing a much smaller boost plane that was easier to control to get it up to altitude.

Well, that was only added after Challenger, and my ET is white, so... I am just going to say that this is a replica of STS-1, and walk away from a fumble like nothing happened.

Rune. Geekiness to the rescue!

Ah a shuttle geek like me

Edited January 3, 2015 by Naito

[Rune]

It is really great work, tricky ascent, tricky landing, as in real life. And, if you slightly move wing to the forward, it is greatly increased flight possibilities of your shuttle. Like on pictures:

http://i.imgur.com/vizWAsn.jpg

http://i.imgur.com/UlmgGEs.jpg

Thanks man! And yeah, CoL is not on top of the CoM... but seriously, you don't want it there. It sits far too low from CoL! It would make quite the unstable craft even unstable-er, and make it go upside down at the slightest AoA. Besides, I'm not finding any issues with lack of control, as other posters say, you can flip her out really easy already.

That's kinda what I did when I was designing my orbiter =p

http://i.imgur.com/866N6BTl.png

FYI it flew, but not very well. I ended up designing a much smaller boost plane that was easier to control to get it up to altitude.

Ah a shuttle geek like me

I think it's geek in general

Rune. And proud of it!

[inigma]

Well I succeeded in transporting and drop testing your shuttle for glide tests:

Your shuttle has a horrible glide slope. I was unable to land it at KSC, but again I was only dropping from 1200m. Maybe I should drop higher? Also you have to pretty much cut the engines on the I-80 to successfully peel away from the shuttle's falling style lest you crash the tail. If you could post a video of how to land this things, let me know.

I was able to land the I-80 with your Shuttle on top without any issues.

[Mesklin]

Thanks man! And yeah, CoL is not on top of the CoM... but seriously, you don't want it there. It sits far too low from CoL! It would make quite the unstable craft even unstable-er, and make it go upside down at the slightest AoA. Besides, I'm not finding any issues with lack of control, as other posters say, you can flip her out really easy already.

Reason for placing CoL exactly under CoM is increasing lift of wings, not stability. Best stability as now with so low placement of wing are impossibly, you are right. But, with this position of CoL your elevons are almost in zero position in all gliding time (except maneuvers, of course), that decrease vertical speed by 2-3 m/s and greatly increase your chance for normal landing

P.S. Sorry for my English, it is not my native language

[inigma]

Rune, looking at Westi29's shuttle which is a very stable glider, I recommend you double the wings, and use offset to sandwich them on top of each other.

[Majorjim!]

Rune, looking at Westi29's shuttle which is a very stable glider, I recommend you double the wings, and use offset to sandwich them on top of each other.

This. It will give the wings a more realistic depth too.

[Rune]

Reason for placing CoL exactly under CoM is increasing lift of wings, not stability. Best stability as now with so low placement of wing are impossibly, you are right. But, with this position of CoL your elevons are almost in zero position in all gliding time (except maneuvers, of course), that decrease vertical speed by 2-3 m/s and greatly increase your chance for normal landing

P.S. Sorry for my English, it is not my native language

You know what? I should have know you knew more than I was gleaning from your post. Thanks! I will totally keep that in mind, because I hadn't thought about that... the canards are lifting up, yeah, but all the elevons lift down. Obvious now that you have pointed it out!

Rune, looking at Westi29's shuttle which is a very stable glider, I recommend you double the wings, and use offset to sandwich them on top of each other.

I know, I'm working on a "fat wing" SSTO right now. That one will do the same thing, with only 30 more parts (lots of intakes!), a third of GLOW, and 100% recovery and much less hassle the whole way. This is not meant to be practical. It took a lot of trial and error to get a glider that could be landed, but only just. In case you want to try things again, initial height shouldn't have much to do with it: with empty tanks and no payload, let her fall with the nose 5º below the horizon. The slope will progressively become less steep as the wings bite into denser air, and you will end up at about 70-80m/s (surface) with a vertical speed of about 20-30m/s by the time you reach sea level. As I said, totally not survivable. But during the last tens of meters (the window to do that is about a couple seconds long), you can pull up like there is no tomorrow (ok, if you go much over 30º you will lose control, but as much as you dare), and you will exchange about 10m/s in forwards velocity for the energy required to get vertical speed under 10m/s. Note that if you do that 5 seconds or more before you hit the ground, your speed will fall too much, and you will again increase your vertical speed and pancake on the runway. But thanks for the suggestions anyway! It seems I will have to do that "easy mode version" after all.

Rune. Being honest with myself, I might have overestimated the difficulty in landing the RL shuttle. But all those "flying brick" comments! The chase F-5s have to force the descent with the engines pushing just to keep up!