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Talk to me about space planes...


Kromey

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Space planes look cool. Really cool. Really really cool. On that point alone I will eventually build and fly them myself. :cool:

What I'm more interested in here is the practical benefits of space planes over rockets. I know that real-life space programs are moving more toward them, and it seems that KSP players have a similar inclination towards them; the latter could just be because they're cool, but I'm pretty sure the former wouldn't be moving that way if there weren't something there. Surely there's more to space planes than just looking cool, right?

Also, in a similar vein, any tips for how to fly them in KSP? So far my only flight ended in the tragic death of that unforgettable, brave Kerbal, ...uh... What's-His-Face. ;.; (Ironically, despite my ignorance of jet engines cutting out at very high altitudes due to no air and that resulting in an asymmetric flame out and flat spin, I managed to regain control only to crash horrifically when attempting my landing.) I'm sure there's some practice to be done, but are there tips or tricks in the controls or basic flight practices that a newb Kerbal pilot such as myself should know?

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The main purpose of course is reduced cost. It's a re-usable craft so all that is lost each launch is the fuel itself. This also justifies spending more on the craft itself to make it more efficient. And typically they ARE more efficient on fuel.

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I know that real-life space programs are moving more toward them

That's far from true. In hindsight the shuttle program didn't turn out to be such a good idea. Whatever it's achievement are it didn't achieve it's primary goal of cheap access to LEO. Instead it turned out to be one of the most expensive launchers on a kg to orbit basis. NASA is giving up spaceplanes to go back to Apollo style capsules with Orion. In the mean time Russia gave up on the Kliper (and Buran), ESA gave up on Hermes and China long ago gave up on their Tianjiao 1. The only serious work going on in space planes these days are USAF's X-37, Dream Chaser and Skylon. Compared to the three capsules in development ( CST-100, Rus and Orion) and three in active use (Soyuz, Shenzhou, Dragon).

Basically both in KSP and in real life spaceplane have very narrow use. For lifting big payload to orbit expandable rockets are the way to go. If you want to lift people up or bring them down capsules on top of expandable rockets are quite adequate. The only really useful thing is if you want to bring people down AND G load must be small (say it's an orbital medical emergency), then you may consider a spaceplane.

Otherwise, you basically only build spaceplanes to show off.

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I assume your talking about SSTO Spaceplanes

Benefits

* Completely re-usable. This will make them cheap when costs is added.

* Can easily land at a specific location where there is an atmosphere and a runway or just a flat area.

Drawbacks

* Modest payload capacity.

So basically they make great bus for Kerbals. More than anything though they are just damn fun.

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Also, in a similar vein, any tips for how to fly them in KSP?

I learned to fly (and land in one piece, which took a bit longer) using the stock albatross. I'd suggest getting the hang of it using planes with a decent bit of lift before you move on to spaceplanes.

Once you're trying to fly spaceplanes, use turbojets and plenty of intakes for high speed/high altitude flight. You want to get most of your speed from the jets somewhere above 13km (throttle down jets when you start running out of air, they're more efficient that way), then use a rocket to circularize your orbit.

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So, bottom line is that they're cool, fun, and challenging (which is more than enough to guarantee I will play with them), but until Career Mode and/or costs are implemented nothing tangible/concrete.

Would be fun to play with them and see if I could build a heavy lifter space plane though... :D I'm sure it's been done, but I like seeing what I can design myself, y'know?

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Spaceplanes are HARD. It could be just my n00bness, but I simply couldn't get one into orbit until recently. Now I've learned of the advantages of multiple air intakes and a single engine to prevent fatal spins when I run out of oxygen. I still cannot manage to make a SSTO spaceplane with the Mark 3 cockpit and fuselage. I personally enjoy capsules much more, with their Rube Goldburgian decouplers and staging.

But yeah, in theory a spaceplane would be perfect for servicing Earth/Kerbin orbit, as it could launch with cargo, drop it off, then return, preserving the launch vehicle itself. However, the shuttle required a complex booster system (and extremely dangerous in hindsight, as I've found from modelling it in KSP), so it was pretty much half-rocket itself. Spaceplanes do provide great cross-range capabilities, which comes in handy if your landing site becomes suddenly unavailable due to weather. The Skylon spaceplane looks quite promising, with its dual-purpose engines. We'll have to see if it becomes a success or not.

And all I have to say for a heavy lifter spaceplane: Good luck! You'll need it... :)

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but until Career Mode and/or costs are implemented nothing tangible/concrete.

No, there are some tangible advantages; they're just extremely specialized. For instance, landing on a planet with an atmosphere is MUCH easier with wings than using a brick, even with parachutes. Not only is it just easier to land in general on these planets/moons, it's much easier if you're trying to land at a specific spot (an anomaly, a base location), especially on bodies that aren't tidally locked.

But in general, right now spaceplanes are basically a proof of concept. We're trying to do things in ways that aren't incredibly wasteful, even though they're quite a bit harder to use.

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There's a massive advantage to using spaceplanes on Kerbin vs Earth, in that you can get most of your orbital speed just with jet engines. If you can get your plane over the hump of around 40km altitude and still be going up then you're probably laughing all the way to orbit. Spaceplanes can have a larger proportion of their weight as cargo because they're getting lift from wings for a lot of the way up rather than the engines overcoming drag *and* providing lift - I have a 74t plane ( fully fuelled & otherwise empty ) which has so far lifted 25t to 100km orbit, I've not got anywhere near that efficiency out of a rocket yet.

I tend to mostly use mine for shuttling Kerbals around - having a couple of designs for anything up to 18 saves me messing around - and launch hardware on rockets still as my cargo spaceplane is rather limited physically. I'm trying to design a piggyback cargo plane for taking bulky but relatively light things like large rovers to orbit, but there are some really horrible issues to overcome there; quite apart from simple matters like loading it, there's nasty thrust asymmetry once you're not bearing weight on the wings.

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If space travel ever became an everyday thing, at least going to and from orbit from multiple locations on Earth, I'd imagine spaceplanes would be quite useful in that they can be landed much more easily, safely and in more locations than rockets. Spaceplanes could regularly come down at standard airports, and take off from them too.

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Well that might depend on the fuel - as far as I remember jet fuel is pretty easy to handle, oxidizers ( Skylon uses what presumably would be a considerable quantity of liquid oxygen ) on the other hand are a whole new thing and I'm not sure I'd want them around somewhere busy like Heathrow :o. However yes, they can make some good use of existing infrastructure, there's airfields all over the place. Just in the UK we're still closing military airbases, and some of those have gigantic runways.

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  • 1 year later...

This thread is pretty old, and spaceplanes in the game have changed quite bit since then. Feel free to start a new thread on the subject, but the info in this one may be out of date.

So please check the last post dates on threads before bringing up one that might be outdated.

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