Space planes suck, specifically the MK3 parts?

[LogicEngine]

TLDR; runway-launched spaceplane engineering is, and has always been, garbage in KSP.

I've got lots of time in kerbal. Making rockets is a piece of cake. Docking is a piece of cake. Making airplanes that fly on Kerbin is a piece of cake (just keep center of mass in front of center of lift). Making SPACEPLANES is NOT possible with vanilla parts.

The concept is simple - have some supersonic atmospheric engine(s) to get up to ~20km altitude at high horizontal speed, then switch to vacuum engine(s) for the rest of the orbital burn. However, the logistics of this process are broken.

If you go small (MK1 body with 2 or 3 engines), they can leave the planet, but require refueling in orbit before traveling to another planet, and can't bring cargo/equipment/ore mining because lightweight build. R.A.P.I.E.R. engine is NOT viable - too inefficient in space and insufficient thrust in atmo. Best option I've found is 1 ramjet and 2 NERVs - no oxidizer mass. Only practical use for this design is a pick-up mission, where you launch a plane, ALSO launch a fuel rocket, meet them in orbit, have the fuel rocket CARRY the plane as far as you can engineer it to, then feel good about saving $30k when you land the plane on the runway, after throwing away your $300k (including launch) fuel tugboat. Why not just do a rocket in the first place?

**If you build big (MK3 parts with that sweet space shuttle 4-person cockpit), you will never leave Kerbin without mods/cheating. The mass of the parts gets out of control - add more fuel, and your engines can't power the ship. Add more engines, need more fuel. It's a runaway loop. Just getting into orbit, using MK3 body, launched from runway, is almost impossible, let alone going to another planet without a fuel tugboat. I've tried with all the various supersonic atmo engines and all the rocket engines. NERV nuclear engine is super efficient and uses no oxidizer but it's SO heavy and weak that adding enough of them to get enough thrust to orbit a MK3 body means you need a huge pile of atmospheric engines to get going, and now you have 30tons of engine and 300tons of fuel and your plane costs $500k and don't get any farther than you did with 1/10th as much power and fuel.**

In my mind, the single most significant purpose for a spaceplane is to go to Eve, where the gravity and atmospheric pressure makes rocket launches brutally challenging, but planes fly with ease in the think atmosphere. In this vein, the notion of making a plane that can fly to Eve and come back (once all parts are unlocked via science tree) should be sanctioned by the game design. I'm not here to build airplanes for fun; I'm here to engineer spacecraft. Why is the planet designed like that if not to encourage the use of wings and atmospheric engines? THERE ARE ONLY 3 BODIES WITH ATMOSPHERE IN THE GAME OTHER THAN KERBIN. TOP TIER PLANES SHOULD BE ABLE TO GO TO THOSE PLACES AS EASILY AS ROCKETS DO.

Unless I am missing something major, I believe that spaceplanes are uselsss and the parts for them are an offensive waste of resources.

[GunnyErmy]

You hit some points and miss some others. So, yes and no. I love spaceplanes, but they have their place. After much practice with them, I feel confident in saying that with the exception of Laythe, they are really only better than a rocket in LKO. I have a spaceplane in my workshop, called the Explorer 2, Mk3 with the sweet 4 person cockpit, that makes LKO quite easily, lands on Minmus, refuels with the ISRU, and then can go anywhere in Kerbol system you want; without mods, without cheating. It's certainly not the first. Feel free to try it if you like. It's something like 240 tons if I remember right. Is it more efficient than a rocket? I haven't done the math, but I severely doubt it. The amount of fuel required to haul an aerodynamic shape around the Kerbol system is probably not worth it. On top of that, it's way too heavy to land on Laythe; I've tried, multiple times. It's fun to SSTO, that's it.

SSTO's shine in LKO, however. Supporting orbital stations, even out to Minmus, LKO rescues, tourism hops, delivering relay satellites - all for the cost of fuel. A dedicated Laythe SSTO, operating from a Jool or Laythe station is also pretty handy.

[Azunai]

people have been building successful spaceplanes in KSP for years. both for simple LKO transports and for interplanetary travel.

obviously the main use of spaceplanes is to get stuff to kerbin orbit cheap. there really is little point going any further with a plane since the wings and jet engines and spent fuel tanks are just dead weight after you reached orbit, but it's entirely possible to build an SSTO that can (for example) reach duna and return without refuelling.

or you add an ISRU converter and drills and just refuel in site, which increases your range to essentially almost anywhere if you just have enough deltaV left to get to minmus and land for your first refuelling stop.


building an SSTO with MK3 parts is kinda tough if all you have is the crappy panther engine. once you have ramjets or rapiers it's a cakewalk, really. with a little experience in designing SSTOs it's really not a big deal to build an MK3 plane that can deliver for example one of those big orange jumbo fuel tanks to orbit. with a bit of creativity you can also use planes with cargo fairings to deliver more or less arbitrary sizes and masses of payload to oribit


EDIT: also, eve doesn't have oxygen. jet engines don't work there. people wouldn't consider eve the hardest planet if you could just use OP rapiers to get to orbit for free lol

[Chibbity]

Space planes/SSTO's are all about reusability and the place that benefits you the most is for short repeated trips to and from LKO.

That is the point of spaceplanes/SSTO's, rockets are better at everything except reusability.

If reusability doesn't benefit the mission you are trying to accomplish, use a standard rocket.

Basically, space planes/SSTO's don't suck; they just fill a very niche role.

[F.C.]

Mk2 and/or Mk3 version of the rapier, panther, whiplash & nerv would be great though.. Main thing stopping me from building bigger spaceplanes is having to double or even quadruple the amount of engines..

[MechBFP]

Eve has an atmosphere, but it doesn’t contain oxygen. So jet engines don’t work there.
Also SSTO spaceplanes are garbage in real life too.

[Goofball]

>the inpossible technology isnt possible in the realistic game


NOOO WAYYYY YOU ♥♥♥♥♥♥♥ SPACE TARD

[כְּפִיר]

I love the idea of a SSTO plane, but....

Even the space shuttle needed a rocket to haul it into space. There have only been engine tests of other possible SSTO designs afaik, but there has not been any feasible real world tests of any SSTO plane that can carry an acceptable payload. I wish a feasible SSTO plane was possible, but its simply not with our current technology. The current designs havent seen real world tests because the engineers realize its just not feasible imo.

So, if a SSTO plane isnt feasible in real life, it shouldnt be in KSP either, unless the player has no concern about any realism.

[GunnyErmy]

引用自 MechBFP：

Also SSTO spaceplanes are garbage in real life too.

Most likely true, especially with Elon nailing reusable rocketry now (the main selling point to the spaceplane) but, to be fair, there hasn't really been a successful one yet - which highlights the difficulty more than the usefulness.

[MechBFP]

引用自 GunnyErmy：

引用自 MechBFP：

Also SSTO spaceplanes are garbage in real life too.

Most likely true, but, to be fair, there hasn't really been a successful one yet.

And there won’t be until they invent an engine with a very high ISP and good TWR that can be used in the atmosphere as well as vacuum.

[GunnyErmy]

Bah you're quicker than my edit lol. But, yes, it remains whether the SABRE engine concept will work.

[Washell]

引用自 LogicEngine：

Unless I am missing something major, I believe that spaceplanes are uselsss and the parts for them are an offensive waste of resources.

Something major: https://www.youtube.com/playlist?list=PLKoQn-aggf8-reU1GL0dTUKKdEfct43dq
Something really major: https://www.youtube.com/watch?v=yPSk4aaTY7k&list=PLKoQn-aggf8_L5ST0GHFJ3mIQsLLgSme4&index=6&t=0s
https://www.youtube.com/watch?v=DYekesK3yTs&list=PLKoQn-aggf8_Zk7gBUlB1VW12M3tEEe50

[XLjedi]

I don't use rockets... and have built several Mk3 Space planes. I only use stock parts and never cheat my way into orbit.

I keep them here:
https://kerbalx.com/XLjedi/craft

This one landed on Duna, refueled and made the return trip home with no support other than the ISRU rover I loaded for the trip (as seen in the associated video):
https://kerbalx.com/XLjedi/SC-20-Monarch

It can be done, but my current preference for Mk3 space planes is to ferry fuel (45-60t at a time) to an LKO station (faster and cheaper than a rocket) and let my nuclear light carriers move between orbital stations.

As for Mk2 space planes... those are fairly simple. I have some scout-class Rangers that I planet hop with that can refuel themselves on site.

I will not deny however, the game could use some additional stock space plane parts, and I could name several off the top of my head that I think are needed.

[XLjedi]

引用自 F.Ch86：

Mk2 and/or Mk3 version of the rapier, panther, whiplash & nerv would be great though.. Main thing stopping me from building bigger spaceplanes is having to double or even quadruple the amount of engines..

So build your own RAPIER-array engines. Most of the big sci-fi ship engines are clusters of smaller engines anyway. We are somewhat limited on shrouding them in a more fashionable way.

[Wobbly Av8r]

Wow!

XLjedi - Nice work! You're an inspiration. If seeing your craft do their thing doesn't convince someone it can be done, nothing would!

[XLjedi]

引用自 Wobbly Av8r：

Wow!

XLjedi - Nice work! You're an inspiration. If seeing your craft do their thing doesn't convince someone it can be done, nothing would!

Thanks, I appreciate the comment.

They don't have to see em... They can download and fly em!

If you can't point this one at 20° and fly it straight to orbit no one can help you.
https://kerbalx.com/XLjedi/SC-33-Crescent-Eagle

...the thing is faster than a rocket to orbit. Fuel spent is typically under 9k per trip to put 10,000 units (or 50t) of liquid fuel in orbit. Conservatively, that's like 180 credits per ton of fuel. I've heard people get under 100 per ton, but I'm impatient and tend to trade efficiency for speed. I also like the flexibility of the design and how it flies in various configurations.