SSTOs! Post your pictures here~

[Jouni]

You said SSTO are not challenging... Which they are, They are fun, and challenging.. I have spent MONTHS trying to do what I described in my first response and have yet to accomplish such a thing.

I do not know what RSS is, I do not use any mods.

I said that getting the spaceplane to orbit is way too easy once you learn to do it, and as a result they feel more like scifi toys than spaceplanes. If I tried to build spaceplanes that can achieve even more impressive feats, they would just feel even more silly.

RSS is a mod that changes planets and their distances to a similar scale as in our solar system. The velocity at LKO becomes something like 7.8 km/s, but turbojets don't let you fly any faster than in the stock game, so you'll need a lot of fuel for the rocket engines to reach orbit. More than going to Duna and back in the stock game, in fact.

[Fellow314]

The same could be said of playing with rockets. They're just not big enough to feel realistic.

There are as many right ways to play the game as there are people that play it.

Yours.

Mechjebby, Airhoggy, Partclippy Fellow.

[Topazium]

This is the smallest SSTO, fully reusable craft I've built. It was designed as a cheap space taxi to dock with a space station I never built.

[KerikBalm]

Doing that would only make the problem worse. The issue is with the small scale of KSP that works much worse with spaceplanes than with rockets. While KSP rockets behave roughly in the same way as real rockets, spaceplanes feel more like stuff from not-so-realistic science fiction. There are basically two solutions to the problem: play with RSS (which requires too much mods for my taste) or avoid using high-altitude airbreathing engines.

Indeed, its quite unrealistic. I think all these part clipping/air hogging or mod designs only make the problem worse.

However, there are limitations of KSP that make things harder:

The inability to have two craft flying in the atmosphere farther away than 2.5 km/under some form of control at once.

You simply cannot do an X-15 or Spaceship1 style space plane without the carrier plane "despawning"

Which means if you want to have a 100% recoverable system, you've got to take all your aerodynamic surfaces and airbreathing engines with you into space. I would much rather be able to launch a scramjet powered craft at 25km, and have an autopilot bring the "mothership" or "carrier" back to the spaceport.

Basic jet engines: seem fine, I guess

Turbojet engines: Function more like ramjets or scramjets.... not too unrealistic. consider the SR-71, A combination Turbojet/ramjet, reached speeds of nearly 1,000 m/s, which is the speed at which turbojets thrust starts to decline, but the speeds attainable are more into scramjet territory.

But here we get into the problem of the scale that you mentioned: with such a small planet, orbital speed isn't that high.

http://en.wikipedia.org/wiki/Boeing_X-51A

http://en.wikipedia.org/wiki/Scramjet#Advantages_and_disadvantages_of_scramjets

A scramjet in practice has reached speeds in excess of 3km/sec -> far less than orbital velocity for earth, but far more than orbital velocity for Kerbin. I'm not sure if its "reasonable" to scale that speed down to the roughly 1,500 m/s that is attainable in KSP (without air hogging with many clipped intakes, or cubic struts to put ram air intakes all over the place)

Then we have the ISP issue. The ISP for scramjets (as stated in wikipedia) is between 1,000 to 4,000 seconds. KSP turbojets are operating at about 800 when high in the atmosphere.

The problem (I think) is that they are listing *effective* ISP. If you halve the exhaust velocity, with the same energy, you can accelerate 4x the amount of propellant/reaction mass. IRL jet engines are so much more efficient than rockets for 2 reasons, and neither is a higher real exhaust velocity.

This doubles the change in momentum per unit energy.

#1) They don't carry oxidizer

- No explanation needed, is there?

#2) They don't carry much reaction mass to speak of

-The mass of the fuel compared to the mass of air accelerated, is quite small

Jet fuel is basically an energy source, not reaction mass. Turbofans are more efficient than turbojets because they accelerate more air, at lower speeds. For practical purposes, we can say they have a higher effective ISP "change in momentum per unit of fuel"

The problem is... KSP takes this into account twice.

The ISP value for Jet engines would be realistic as an "effective ISP". The problem is this ISP is then multiplied by ~15 to reach an effective ISP that is 15x higher. Jet engines consume intake air to jet fuel in a 15:1 ratio. If intake air were considered massless like electric charge, this would be fine.... but its not, it has mass, and I'm pretty sure jet engines have effective ISPs that are about 15x too high.

Either they need to reduce jet engine ISP, and then play with the intake air:jet fuel burning ratios, or keep their high ISP, and treat intake air as massless.

Of course, I think in this case, we'd also need jet fuel containers that contain more jet fuel (In KSP, rocket fuel tanks hold much more weight in fuel + oxidizer than the weight of liquid fuel that a jet fuel container holds. Rocket fuel containers are also much "denser")

So the issues are:15x too high effective jet ISP, and kerbin is too small. (and the aerodynamic model is still pretty bad, I hear FAR can fix that though)

As a first fix, I'd change intake air to be massless - that is the simplest fix, rather than tweaking the engine ISPs.

Go into your file, set intake air to have no mass, then try to make SSTOs... its going to be a lot harder.

[Jouni]

The same could be said of playing with rockets. They're just not big enough to feel realistic.

Real rockets aren't actually that big.

For example, consider the Delta IV Heavy, which is among the biggest rockets anybody uses at the moment. The Common Booster Core is about 40 m long and 5 m wide. Because kerbals are half the size of a human, everything in the game feels twice as big as it is. As a result, we can pretty much simulate the CBC by a stack of two jumbo fuel tanks and a Mainsail. The Delta IV Heavy has one CBC as the first stage and two as boosters. The second stage is quite tiny: 13.7 m long and 5 m wide. In KSP, I would probably simulate it with an LV-T909 engine and an X200-32 fuel tank. Overall, we have 6.5 orange tanks worth of fuel, so most people would not consider it a heavy lifter in KSP.

[Rune]

I said that getting the spaceplane to orbit is way too easy once you learn to do it, and as a result they feel more like scifi toys than spaceplanes. If I tried to build spaceplanes that can achieve even more impressive feats, they would just feel even more silly.

RSS is a mod that changes planets and their distances to a similar scale as in our solar system. The velocity at LKO becomes something like 7.8 km/s, but turbojets don't let you fly any faster than in the stock game, so you'll need a lot of fuel for the rocket engines to reach orbit. More than going to Duna and back in the stock game, in fact.

You could always forget turbojets and go with plain jets, and then you would lose atmospheric thrust much earlier (10,000-15,000m), so if you scale things, you would get closer to "realistic" mass fractions. But mind you, it'll never be really realistic, since mass ratios and T/W in the stock game are unrealistic themselves. But if you accept everything is more or less scaled, yeah, plain jets would get you a better scaled response, where the airbreathers give a tiny fraction of the orbital velocity, and you need to pack about as much delta-v as in the upper stage of a two-stage rocket.

Rune. The resulting designs also have awesome range if refuelled at LKO.

[TeeGee]

The hardest part about SSTO's is learning how to fly them, not in how to construct one.

I've built 4 part SSTO's the get to and from orbit because I know how to fly them

Here is the trick:

1) Get out of the thick atmosphere ASAP. Climb as fast as you can until you reach 10km. Now you can start accelerating horizontally.

2) After you've left the thick atmo, look at your vertical speed indicator and keep the needle next to 100m/s. DO NOT GO OVER THIS VERTICAL SPEED! Vertical speed = rate of climb. Too fast = bad because too high = less air to breathe for you engines = burnout = no thrust = no orbit.

3) Keep the vertical speed over 0m/s (obviously). If you go under that value, it means you've reached your apoapsis and are on your way back DOWN... that's bad. I NEVER go under 30ish m/s vertical speed.

4) 4 Ramjet intakes/1 turbofan engine.

5) Keep your planes weight DOWN. If you are ONLY going into orbit, don't take 10,000 units of fuel on you.

6) Oxidizer weighs a TON. Keep this number as low as possible.

7) Spaceplanes look cool but are not efficient, weight wise. Wings add unnecessary weight because once you get into space, they are USELESS. Same goes with turbofan engines. But hey, if you guys want to build spaceplanes, go right ahead. I've been building SSTO planes since I got into this game, mastered it, then started using KSP air breathing engines differently.

8) Keep you air breathers ON as long as possible. So as you reach 32 km, that is the ONLY time you can reach orbital velocity cuz the air is thin enough up there. To keep your engines on, throttle DOWN as you get higher and higher.

Remember RULE #1: GET OUT OF THE THICK ATMOSPHERE SOON and KEEP YOUR VERTICAL SPEED AROUND 100m/s.

Do that an you'll make orbit every time.

[Hodo]

Doing that would only make the problem worse. The issue is with the small scale of KSP that works much worse with spaceplanes than with rockets. While KSP rockets behave roughly in the same way as real rockets, spaceplanes feel more like stuff from not-so-realistic science fiction. There are basically two solutions to the problem: play with RSS (which requires too much <[Incorrect "to many" is what you are looking for.] mods for my taste) or avoid using high-altitude airbreathing engines.

First I would kill your argument with this statement here, it is a game. Next mods are what make KSP fun, the stock base, KSP is pretty bland and incomplete currently. It can be fun for a a few hours but once you have a basic understanding on how the game works you can do anything. The first time I played KSP my first rocket I launched made it to a 250km x 250km orbit. All I did to learn how to do that, was watch a single Scott Manley video.

The thing is in real life there are some jet engines that can operate at super high altitudes, look at the U-2 and the SR-71, both were capable of operating well above 20km altitude. The SR-71 set the absolute altitude record of 25,929m! Which oddly enough is about where most of my jet engine SSTOs cut out in FAR+KSP using a single intake per engine. The U-2 operated around 21km altitude again in stock KSP that is REAL high, but in the Real Scale System mod, that is about 80km short of space.

Making a SSTO with the RSS mods and the required mods to make it realistic, KSP becomes a much different game. Even launching a successful rocket in career mode becomes a challenge. So don't bash SSTOs, saying they are sci-fi or easy, when you haven't fully explored the options with mods that make the game harder. I don't even bash the people who make stock monstrosities, or only use mechjeb to do things, I often am interested to see what they come up with, what bits of amazing imagination that they use to create these craft. Sure they most likely will not work in a realistic environment but that is KSP.

You said SSTO are not challenging... Which they are, They are fun, and challenging.. I have spent MONTHS trying to do what I described in my first response and have yet to accomplish such a thing.

I do not know what RSS is, I do not use any mods.

This is a video game, it is not realistic, play it how you want to play it, and have fun doing so.

on a side note, an SSTO does not need to be an aircraft, it can be a rocket, as long as it stays in one piece, drops no parts, and gets to orbit as a single stage.... that is SSTO.

Single Stage To Orbit ~ ~

I really suggest you try a few plugins FAR and DRE are great ones that actually make KSP respond like a realistic atmosphere, which is nice.

Real rockets aren't actually that big.

For example, consider the Delta IV Heavy, which is among the biggest rockets anybody uses at the moment. The Common Booster Core is about 40 m long and 5 m wide. Because kerbals are half the size of a human, everything in the game feels twice as big as it is. As a result, we can pretty much simulate the CBC by a stack of two jumbo fuel tanks and a Mainsail. The Delta IV Heavy has one CBC as the first stage and two as boosters. The second stage is quite tiny: 13.7 m long and 5 m wide. In KSP, I would probably simulate it with an LV-T909 engine and an X200-32 fuel tank. Overall, we have 6.5 orange tanks worth of fuel, so most people would not consider it a heavy lifter in KSP.

Do you realize that the Delta IV Heavy is 12 stories tall! 40m is nothing to scoff at, that is almost 20 men standing on each others head. And the amount of power the DIVH has in its main boosters is considerably more than what we have in the stock KSP boosters. Because they are scaled for Kerbin.

[9t3ndo]

Main Engine Test SSTO

Testing my new main engines for my next SSTO.

Lateral mountable, equiped with 1 Nuke and 2 Turbo Jet's

Doing in first test flight an easy 500k orbit.

[Fellow314]

Real rockets aren't actually that big.

For example, consider the Delta IV Heavy, which is among the biggest rockets anybody uses at the moment. The Common Booster Core is about 40 m long and 5 m wide. Because kerbals are half the size of a human, everything in the game feels twice as big as it is. As a result, we can pretty much simulate the CBC by a stack of two jumbo fuel tanks and a Mainsail. The Delta IV Heavy has one CBC as the first stage and two as boosters. The second stage is quite tiny: 13.7 m long and 5 m wide. In KSP, I would probably simulate it with an LV-T909 engine and an X200-32 fuel tank. Overall, we have 6.5 orange tanks worth of fuel, so most people would not consider it a heavy lifter in KSP.

In KSP 'heavy lifters' lift a craft capable of sending Kerbals to the surface of all five planets of Jool and back again.

That's one orbital capable vehicle lifting five other orbital capable vehicles into low orbit with enough delta V for the Kerbals to travel there and back.

I wonder how heavy a lifter would be to manage that in real life for Jupiter?

Wikipedia tells me the Delta IV Heavy can lift 9,306 kg to escape velocity, but it's not verified.

[Yakuzi]

(which requires too much <[incorrect "to many" is what you are looking for.] mods for my taste)

Incorrect "too many" is what you are looking for, if we're gonna be grammar ****'s

But yeah, vanilla KSP is awesome but not complete, so be happy/grateful there are so many mods that allow you to create the experience you're looking for.

[Hodo]

Incorrect "too many" is what you are looking for, if we're gonna be grammar ****'s

But yeah, vanilla KSP is awesome but not complete, so be happy/grateful there are so many mods that allow you to create the experience you're looking for.

Yes thank you, sometimes when I type in a hurry I forget to check my spelling.

[Jouni]

Next mods are what make KSP fun, the stock base, KSP is pretty bland and incomplete currently. It can be fun for a a few hours but once you have a basic understanding on how the game works you can do anything.

I have played KSP for a few hundred hours, mostly stock, and I still have a lot to do in the game. The only gameplay-changing mod I use is the Kethane Pack, mostly to save time spent in refueling operations.

The first time I played KSP my first rocket I launched made it to a 250km x 250km orbit. All I did to learn how to do that, was watch a single Scott Manley video.

The first time I played KSP, my rocket first deployed parachutes, and then fired upper-stage engines. I had assumed that stage numbering went in the same way as in the real world.

The thing is in real life there are some jet engines that can operate at super high altitudes, look at the U-2 and the SR-71, both were capable of operating well above 20km altitude. The SR-71 set the absolute altitude record of 25,929m! Which oddly enough is about where most of my jet engine SSTOs cut out in FAR+KSP using a single intake per engine.

That 26 km altitude record corresponds to something like 15-17 km at Kerbin, because of different scale heights. A Mig-25 once went over 37.5 km, but not in level flight, and even that is less than 25 km at Kerbin.

So don't bash SSTOs, saying they are sci-fi or easy, when you haven't fully explored the options with mods that make the game harder.

I'm not bashing anything, I'm just saying that I feel that stock spaceplanes are boring, because they work in a completely different way than real spaceplanes would.

Do you realize that the Delta IV Heavy is 12 stories tall! 40m is nothing to scoff at, that is almost 20 men standing on each others head. And the amount of power the DIVH has in its main boosters is considerably more than what we have in the stock KSP boosters. Because they are scaled for Kerbin.

More like over 60 m with the second stage and payload. Without boosters, it would be smaller than an wide-body airliner.

The engines aren't actually that powerful, just something like two Mainsails each. Even I have rockets with more thrust than the Delta IV Heavy in KSP, and I don't like building big rockets.

[ayana]

after months of attemtps, I finally make a FAR SSTO that doesn't commit suicide on reentry

[KissSh0t]

I'm not bashing anything, I'm just saying that I feel that stock spaceplanes are boring, because they work in a completely different way than real spaceplanes would.

You really don't need to come onto a thread devoted to SSTO and start sharing you're opinion of how SSTO are boring, unrealistic and not challenging... there are many other threads that I'm sure you will find very interesting.

Please do not argue for the sake of arguing, this thread is for people to share their craft, not to debate their personal opinions of how the game should be played.

The most fun part about this game is that you can play it how you want to play it.

Edited March 12, 2014 by KissSh0t

[Commander Jebidiah]

http://i.imgur.com/Cfc400G.png

after months of attemtps, I finally make a FAR SSTO that doesn't commit suicide on reentry

Well done I can't even get an ssto to orbit let alone re-entry and landing I've only made a functioning one once

[ayana]

Well done I can't even get an ssto to orbit let alone re-entry and landing I've only made a functioning one once

it's all thanks to Procedural Wings and the tiny stockalike parts. the standard parts just made the rocket section too heavy and oversized.

[Jouni]

You really don't need to come onto a thread devoted to SSTO and start sharing you're opinion of how SSTO are boring, unrealistic and not challenging... there are many other threads that I'm sure you will find very interesting.

I posted a spaceplane that used basic jets instead of turbojets, and then you started arguing. Eventually other people joined in.

[KissSh0t]

I posted a spaceplane that used basic jets instead of turbojets, and then you started arguing. Eventually other people joined in.

Stop now.

Please.

[Hodo]

I posted a spaceplane that used basic jets instead of turbojets, and then you started arguing. Eventually other people joined in.

Step down off that cross because you ain't Jesus.

[KissSh0t]

Another failed design for Big Red Heavy Lifter... I made this one a while ago but I don't think I showed it... Perhaps showing it will give someone an idea for their own craft.

Considering rebuilding this to have a tail.

[KerikBalm]

Update on this stock non-clipping monstrosity:

Not wanting to use finesse, or multiple quick saves, I delivered a small (<60 ton) payload to obit, and then burned up my excess rocket fuel to come in steep and light just west of KSC. I went a bit farther west than intended, not much of a problem though...

I had checked its CG with tanks neary empty, carrying only 500 units of jet fuel, with payload, etc... everything should have been fine... but around 30-40 km on on reentry... I lost control, it started to yaw uncontrollably, and spun a bit... and then... stabilized... flying backwards - I've had that happen with other designs with a bunch of rearmounted engines and nearly empty tanks - ones that had survivable impacts by firing up the engines and doing a powered descent/vertical crash landing.

This one, I wasn't going to be content to just have it splash into the water at low velocity travelling backwards.... there was no reason for it to be unstable, and I had tested it with more or less the same fuel situation I now had (a take off, 180, return and land), so I fired up the jets, came to a stop, and accelerated forward, and as it should have, it flew forward stably, and flew back and landed at the KSC just fine.

Any ideas on what may have caused the spin on re-entry? or why it would stabilize flying tail first, but be stable when travelling forward?

[KissSh0t]

Empty it's tanks on the build screen and have a look at the center of mass.

*edit*

Ahh.. you already did that xD

Just a hunch.. you have a lot of air intakes in front of the center of mass, I'm just guessing the center of mass so I can't be sure. on re-entry, I wonder if the drag from the air intakes is making it unstable?

Quite the monstrosity indeed.

Edited March 12, 2014 by KissSh0t

[O-Doc]

Update on this stock non-clipping monstrosity:

https://scontent-b-vie.xx.fbcdn.net/hphotos-frc3/t31/q74/s720x720/1781709_10102522555220943_38363739_o.jpg

Not wanting to use finesse, or multiple quick saves, I delivered a small (<60 ton) payload to obit, and then burned up my excess rocket fuel to come in steep and light just west of KSC. I went a bit farther west than intended, not much of a problem though...

I had checked its CG with tanks neary empty, carrying only 500 units of jet fuel, with payload, etc... everything should have been fine... but around 30-40 km on on reentry... I lost control, it started to yaw uncontrollably, and spun a bit... and then... stabilized... flying backwards - I've had that happen with other designs with a bunch of rearmounted engines and nearly empty tanks - ones that had survivable impacts by firing up the engines and doing a powered descent/vertical crash landing.

This one, I wasn't going to be content to just have it splash into the water at low velocity travelling backwards.... there was no reason for it to be unstable, and I had tested it with more or less the same fuel situation I now had (a take off, 180, return and land), so I fired up the jets, came to a stop, and accelerated forward, and as it should have, it flew forward stably, and flew back and landed at the KSC just fine.

Any ideas on what may have caused the spin on re-entry? or why it would stabilize flying tail first, but be stable when travelling forward?

That's a cool design. I'd love to know more about your ascent profile like, what height and speed you get on turbos andhow much percentage weight of rocket fuel you need to get into orbit. I'm guessing you're lighting your rockets at about 20km(14000m/s) for a long burn to orbit with 50% craft weight in fuel. Is that accurate?

As for your tail first issue. Your mass is too far back and the drag is too far forward. Think of an arrow or dart. The heavy end falls first with the light end following. The fix, without re-organising the whole plane, could lie in putting a long tail out the back with some stabilising wings to prevent it from swapping ends during unpowered flight. Also, transferring fuel to forward tanks prior to re-entry is one strategy but, I like to design planes to avoid this as it has the potential to mess up your landing.

[NKL]

Like O-DOC said, drag at front is bad. I use to make small plane when I was rookie in KSP (and I still am ofc !) and put lot of radial intake. or radial intake put a lot of drag. ASYMETRICAL drag in my case... which weaken my pitch autority.......which lead to funky backflips in high altitude