Cygnus Recoverable SSTO Rockets (15 to 600 tons)

[Kerbal101]

This SSTO-R has only 1 tonne payload:

Spoiler

 

 

 

[Warzouz]

@Kerbal101, I may try to aim at 30km, but the issue it messes with targeting KSC. I'll try that even though.

As for chute, you use much more than I use. Even the 600 tons stage has only 24 chute. For a 4 ton per chute, I would need nearly 120 chutes. Instead a slight burn will reduce part count.

Drogues may be not necessary for light stages, but much more useful for heavy ones. I like to test with the 300 tons.

[Kerbal101]

8 hours ago, Warzouz said:

@Kerbal101, I may try to aim at 30km, but the issue it messes with targeting KSC. I'll try that even though.

As for chute, you use much more than I use. Even the 600 tons stage has only 24 chute. For a 4 ton per chute, I would need nearly 120 chutes. Instead a slight burn will reduce part count.

Drogues may be not necessary for light stages, but much more useful for heavy ones. I like to test with the 300 tons.

Screw the smaller fuel tanks above. You are right, TWR should be 1.4 when loaded, otherwise one burns the dV by gravity. Thats a brilliant formula!

I just retested the version with less fuel, and it gets into orbit easily and has enough fuel for small orbit transfer. Just like plane.

Its pretty good thing for early carrier science - and it uses swievels and early stock parts.

 

I don't use drogue, because its locked at higher carrier. The chutes - yes, but why not - I don't want any risk should I lack fuel, I am okay to have less payload for this. For that reason I calculate chute amount to almost empty rocket mass, if it has fuel, it can use it for soft landing.

While Swievel/Reliant are extremely pathetic in weight/thrust (compared even to skipper), in carrier one hardly needs to propell more than 15 tons early.

Aspogragus-type sattelite does the job and after first visit to Mun for science - Docking Port can be unlocked, means orbital assembly for interstellar. Then more science flows in and all other rocket engines are unlocked.

 

Also, you want to be so precise to land near KSC - me personally don't care much. My best design regular rocket costed 60k to fly, where with basic SSTO-R - its 15k in worst case. YMMV =)

[GoldForest]

Hey Warzouz, I got a challenge for you, make Thunderbird 3, the SSTOR from the Thunderbirds Movie(2004)

[ibanix]

Brilliant stuff here, thanks. Saving me lots of $$$.

[fourfa]

Any interest in a 1.1 update?  I'm playing with using the giant heatshield at the front of the lifters, and it seems quite easy to re-enter with all that drag.

[Warzouz]

Yes it could work, but the big launchers would have a 3.75*3  = 1.25m width, so they may not be fully covered by the shield.

For now, I'm playing the career, and I just unlock the Mammoth.

Edited May 5, 2016 by Warzouz

[fourfa]

Actually me too, just filled the tech tree in Hard Mode 1.1.  And I'm designing Cygnus style SSTO lifters - wow, it's hard work!

[Warzouz]

9 hours ago, fourfa said:

Actually me too, just filled the tech tree in Hard Mode 1.1.  And I'm designing Cygnus style SSTO lifters - wow, it's hard work!

Well, it's not hard, flying is even easier. And when you lifter has all it's part at the correct place, you can scale the basic lifter to any payload in less than 10 minutes (I really did the 600t from the 300T in 10 minutes and went to space at the first try (in 1.0.4).

Reentry is harder since 1.0.5. I did a LOT of testing to successful land near KSC without blowing everything.

The inflatable heat shield can be a good asset to create easily scalable reusable launchers. .

[TomDRV]

HI, I'm knew to KSP (less than 12hrs gametime). I'm trying these rockets and I run out of fuel everytime having only reached an apoapse of ~25km. I'm assuming it's my flying . . . How do you get into orbit with so little fuel?

[The Optimist]

12 hours ago, TomDRV said:

HI, I'm knew to KSP (less than 12hrs gametime). I'm trying these rockets and I run out of fuel everytime having only reached an apoapse of ~25km. I'm assuming it's my flying . . . How do you get into orbit with so little fuel?

More information please

[Heckspress]

I think he provided enough info, he's asking a question.

Chill out dude, stop jockeying the newbies.

[Basto]

7 hours ago, Heckspress said:

I think he provided enough info, he's asking a question.

Chill out dude, stop jockeying the newbies.

Well he didn't actually. At what altitude did he start his gravity turn? Which launcher did he use? What was the weight of his payload?

[Warzouz]

On 12/7/2016 at 2:56 PM, TomDRV said:

HI, I'm knew to KSP (less than 12hrs gametime). I'm trying these rockets and I run out of fuel everytime having only reached an apoapse of ~25km. I'm assuming it's my flying . . . How do you get into orbit with so little fuel?

Sorry I didn't see you post.

Beware that this designed was mostly done for 1.0.4. Reentry heat was increase in 1.0.5 and 1.1 so this design may noe be as easy as before.

But your question is about ascent and there shouldn't be any difference with 1.0.4 on that part. You've used all your fuel around 25km ? wow, that's strange...

- Maybe you set a too heavy payload ona given launcher

- Maybe you didn't do you gravity turn correctly (notch at 50m/s)

- Maybe you payload is too bulky or not streamlined

- You are trying to reach a too high orbit. Thoses rockets are designed to go to LKO (75/80 km)

A 25km you should already be at 10 to 30° to the horizon and your engines should still be burning fuel. I don't remember at which altitude I stop burning because I'm usually focused on apoapsis to reach 75km.

In any case, if you have too little fuel, use the next rocket design. But beware that you TWR may be too high so you'll got upward too straight and will do an inefficient orbital insertion. So don't hesitate to lower the thrust on engines before take-off.

[Sharpy]

@Warzouz

Do you plan to release updated version?

I just experienced the updated reentry heat...

 

 

[Warzouz]

I'm not playing much nowadays. Further more, my 1.1 campaign didn't used SSTO rockets. I wanted to do something else.

As for reentry, I noticed the most efficient way it to go into a fast spin. But the drawback is targeting a landing spot is much harder.

[Zamolxes77]

6 hours ago, Sharpy said:

@Warzouz

Do you plan to release updated version?

I just experienced the updated reentry heat...

Most of his rockets can survive the 1.1.3 reentry heat, all except the ones that use the Mammooth? engines. Those have always been very sensitive to overheating, like the Vector.

Technically I manage to bring them back too, but the craft was a chemical SSTO with wings - it would take off as a rocket, then land as a spaceplane on the runway. The large wing surfaces were responsible for a quick aerobreak, keeping the heat within the tolerances for those fragile engines. They turned out to be more of a problem, but I seen several youtube videos with people landing similar crafts - sadly they might not have been 1.1.3

For all other ones, mainsails, skippers, reliants, aerospikes, as long as you enter around 2200 m/s and do several "flips" you should be ok. I haven't tried his exact designs, I always built my own, since career mode was introduced: 100% recoverable craft, you only spend money on fuel. They look eerily similar lol.

[Sharpy]

2 hours ago, Zamolxes77 said:

For all other ones, mainsails, skippers, reliants, aerospikes, as long as you enter around 2200 m/s and do several "flips" you should be ok. I haven't tried his exact designs, I always built my own, since career mode was introduced: 100% recoverable craft, you only spend money on fuel. They look eerily similar lol.

"flips"?

uh, I tried the 15ton version, my payload was below 10 ton, so I was left with plenty of delta-v. I performed the prescribed 70m/s burn, deployed airbrakes, and promptly got them blown off.

Then I managed to save the craft by burning almost all of the remaining delta-v, splashed down in the ocean between deserts and kerbafrica instead at KSC, missed the opportunity to recover when vertical, the top tank splashed down hard, then I spent a good couple minutes at tracking station recovering all the parachutes that survived when the tank they were attached to didn't.

Well, a typical SSTNFO* experience. Maybe just the manual needs updating, I don't know...

 

* Single stage to, not from orbit.

[Zamolxes77]

3 hours ago, Sharpy said:

"flips"?

uh, I tried the 15ton version, my payload was below 10 ton, so I was left with plenty of delta-v. I performed the prescribed 70m/s burn, deployed airbrakes, and promptly got them blown off.

Well, a typical SSTNFO* experience. Maybe just the manual needs updating, I don't know...

Well every time a new patch gets released, "the manual" with flight instructions for previous designs gets tossed out the window. The design is sound, but I was expecting one would know how to fly it, from experience. My mistake, made an assumption. 

Yes, "flips". When you hit atmo, treat the craft like you would a winged SSTO, except backwards, engines go in 1st. They have a decent heat resistance so they make good makeshift heat shields. As you descend, push your craft towards the horizon, up - down, or lateral left - right. You create basically this pendulum movement: you push up, increase AoA, expose more surface to rushing air, you slow down. Pressure pushes your craft back to neutral, so take advantage of that and push with it, creating a wide movement in the opposite direction, hold there a moment, then push again with pressure in opposite direction.

With a craft that is fairly engine heavy, this pendulum motion is enough to slow it down, but generally not enough to avoid losing engines. Some crafts are a bit more unstable, CoM and CoL are far closer, so at some point, craft can tumble end over end, through atmosphere, executing "flips". From one point of view this is highly unrealistic and undesirable, from other point of view, this is extremely useful because it leads to massive drag resulting in a sharp deceleration, while allowing the engines to get out of the way of danger to cool down a bit.

But anything that it has a heat tolerance of less than 2,000 K will be incinerated. By hiding or streamlining every inch of the craft, losing bits can be avoided.

Also one trick to make this process easier, is to add the giant S-wings to your craft. They massively increase the drag, so you can break "harder" into upper atmosphere, avoiding overheating completely. But it will make your craft look funny and they're not really needed with a bit of gymnastics

I should probably post a video on this lol, I kinda want to get into making some.

[Sharpy]

oh, this.

2 hours ago, Zamolxes77 said:

Yes, "flips". When you hit atmo, treat the craft like you would a winged SSTO, except backwards, engines go in 1st.

I got allergic to this early on in 1.1.3, after returning to KSP after a long break...

Made a spaceplane. Not really SSTO 'cause I was still miles from any decent jet engines, so disposable SRB had to do for that segment of flight. Anyway, nose first, the MK1 cockpit would overheat. Tail first, moving off-center, I'd flip and cockpit would overheat. Airbrakes had to be flapped continuously, because without them I'd never slow down enough for drogue to be deployable (or overheat the cockpit, trying). And if even one exploded due to overheating, the torque from the one opposite would turn the plane and the cockpit would overheat.

I got it eventually through flapping them A LOT, I mean deploy, immediately un-deploy (overheat already in the red), wait some 3 seconds, repeat.

...once I got below 800m/s, I just flipped cockpit-forward, and kept gliding... as I saw KSC in the distance, I flew literally meters above the astronaut complex, and landed between VAB and the launchpad.

Regardless... since then I avoid exposing vulnerable parts to heat, even momentarily.

 

Edited September 5, 2016 by Sharpy

[Zamolxes77]

Yeap, heat got a bit more dangerous and I'm fine with that, it should be dangerous ! Is not like dusting crops or peeling potatoes, we're going to space for crying outloud !

[Sharpy]

6 hours ago, Zamolxes77 said:

Yeap, heat got a bit more dangerous and I'm fine with that, it should be dangerous ! Is not like dusting crops or peeling potatoes, we're going to space for crying outloud !

I still need a good plan for deorbiting big things safely. The only one I have that works for sure 100% of the time is "have at least 1500m/s of delta-V and a decent thrust." Yeah, I landed my Claymore, the craft with five long MK3 tanks connected length-wise. I began the deorbit burn with 3000m/s of delta-V and was ending nearly empty though.

[valens]

One possibility to alleviate the heat issue on the AIRBRAKES would be to continuously roll the craft during reentry. One trick, though: since you're entering bottom first, your reaction wheel (should you have any) will conflict with the control surfaces and both will cancel out at one point. I suggest extending flaps at reentry so that they will always point the same direction.

[EDIT:] Fool of me, I did not see @Warzouz suggesting exactly the same a bit higher.

Edited September 6, 2016 by valens
consistency

[Zamolxes77]

4 minutes ago, valens said:

One possibility to alleviate the heat issue on the AIRBRAKES would be to continuously roll the craft during reentry. One trick, though: since you're entering bottom first, your reaction wheel (should you have any) will conflict with the control surfaces and both will cancel out at one point. I suggest extending flaps at reentry so that they will always point the same direction.

Extending flaps ? What are you talking about ?

[valens]

2 minutes ago, Zamolxes77 said:

Extending flaps ? What are you talking about ?

If you put control surfaces (elevons, etc.), you often have the possibility to extend them (with right-click or action groups), which locks them in one position.