Do Re entry gliders work for places like Duna and Eve?

[Moonfrog]

Or is it better to use parachutes?

Been doing a lot of plane stuff, even managed to build a spaceplane that works, not sure, how but only needed something like 1000 delta V of rocket fuel once it was up there. and 80 units of jet fuel.

Is it feasible to leave duna's or Eve's atmosphere in a smilar plane, origianlyl launched on the end of a rocket, but the return ship would be a plane?

[Wallace]

Flying a plane on Duna is possible, I've just landed two small gliders on Duna. Landing is tricky, as the atmosphere is so thin you need to be going a fair speed to get lift, but then you need to get quite slow to land on a bumpy surface, so it's tricky balance to get right, I had to use parachutes to stop one of the gliders.

Gliders are a great way to explore Duna tho, a quick rocket boost up to the mid atmosphere and they can glide for miles and miles with a great view of the landscape.

Taking off and into orbit is a whole other matter, because you need to use rocket engines, so all that efficiency from using jets is gone. Duna is doable, but Eve it is not possible.

[Master Tao]

Duna's and Eve's atmospheres do not contain any oxygen, so you can't use stock airbreathing engines for the return. Laythe is the only other planetary body with oxygen, so you can fly airbreathers there – you just have to find a place to land. You could try building rocket planes, but they'll probably end up less efficient than normal rockets.

If you use mods, there are a few that let you burn alternative fuel mixtures so you can fly on Duna and Eve more efficiently.

[FonVegen]

This will only work if the plane uses only rocket fuel; there is no oxygen in Duna's and Eve's atmosphere.

Also, Eve is incredibly difficult to return from in general, so you would need lots of fuel. On the other hand, Eve's atmosphere is very dense, so you would not even need large wings to take off with a plane.

Duna on the other hand has got a very thin atmosphere, so make sure you have got a large enough wing surface. The thing that Duna has got going for it is it's rather low gravity, which means that you don't need as much fuel for getting into orbit.

So yes, you can use the atmosphere on Duna and Eve, just no jet engines.

[astropapi1]

As you won't be able to use jets in Duna or Eve, all the efficency of spaceplanes is gone, and you're left with a pair of giant, useless wings.

Planes are really good for exploring these places, but ideally, you should decouple the wings and land/take-off like a normal rocket.

[Laie]

a) do reentry gliders work or ist it better to use parachutes?

Depends on what you want, really. If you want nothing more than a safe touchdown, parachutes will be cheaper and more weight efficient *everywhere*. If you want to land at a particular spot, some wings will allow for a few last-minute adjustments. That works much better on Eve than on Duna -- if you haven't been there yet, Duna's atmosphere is so thin as to be almost nonexistant. If it looks like a sailplane, it will glide like a wrench.

It's definitely possible to build gliders or even flyers that work on Duna. But that's quite some effort -- if you only want to visit Duna, parachutes is the way to go.

spaceplanes on eve & duna

Quite pointless in either case. Converting airspeed to lift through wings is quite lossy; it only works because airspeed from jets is so dead cheap (as you noted, you needed only very little jet fuel). If you have to run on rocket power alone, it's better to go up right away.

[Wanderfound]

Depends on what you mean by "better". Chutes are easier to land safely, wings are easier to land at KSC.

It's KSP; do whatever is most fun for you.

[Tex_NL]

In .23 I build a Kethane powered plane for Eve. It entered the atmosphere just fine and it was able to fly from deposit to deposit with ease.

In earlier versions I've flown an electric plane on Duna. I had to reload the entry a few times as the thin atmosphere did not generate enough lift to slow the descent. But once I did manage to land safely it performed as expected: without any problems.

[Clockwork_werewolf]

Taking off from anywhere but Kerbin, wings are mostly useless without mods but landing is a different subject.

Landing wheels are mass-less so they are "free". One radial parachute is 0.15 in mass, and one delta wing is 0.7 so two wings are just lighter than the parachute. One parachute may get you to low speeds but you probably need landing legs to land and parachute have diminishing returns. One parachute might get you to 30m/s from 100m/s but you may need 4 to get you to 8m/s.

Now that I have learned to land with gear (took costs to make me be bothered to learn) I feel like wings are the better option for landing on flat surfaces. On bumpy surfaces, I'm not sure.

Have a go and see how it turns out

[Master Tao]

Landing wheels are mass-less so they are "free". One radial parachute is 0.15 in mass, and one delta wing is [0.07] so two wings are just lighter than the parachute.

Good point. I wonder where the cutoff is between ships that can land on two delta wings, but can't land with a single Mk 16 parachute, which only masses 0.1 tons and costs 1/3 as much. The gliding ability may be worth it.

[WWEdeadman]

You can certainly glide anything with wings to a landing on Eve. Getting back out, probably not, since there is no Oxygen for efficient jet engines. SSTO planes from Eve seem quite impossible. At least I haven't seen any working ones yet. Generaly Eve is a very challanging place to get off of.

As for Duna: The athmosphere is so thin (and, again without oxygen) that you need really big wings and a quite light craft to actually have any effect. But a spaceplane SSTO for Duna would be absolutely no problem. I actually still plan on doing a manned landing with a plane on Duna in my let's play series (the first try at that failed, cause it crashed on Dunas surface. Not ernough wings for the mass)

The real advantage of a spaceplane type lander only really comes out on Laythe. Laythe has oxygen, and a thinner athmosphere and less gravity. Any SSTO plane that can get to Kerbin orbit can land on Laythe and go back to orbit without a problem.

Edited August 9, 2014 by WWEdeadman

[LaytheAerospace]

I've actually made a couple of fairly interesting gliding rovers. The idea was to make a traditional looking rover that could return from the Mun under its own power and land on Kerbin without any parachutes to slow itself down, only the atmosphere (FAR, not stock). Moderate success, but was really surprised when the wings I'd used as structural elements actually gave significant lift and some control of trajectory via the reaction wheels.

Two wings on a 15t rover let me touch down nose-first (believe it or not, this was ideal) at a 'graceful' 90-130 m/s depending on my descent and final altitude. More wings or a drogue chute and it probably could have touched down wheels first at a consistent <100 m/s, but that wasn't my goal so I never pursued it.

Wings can definitely be used to bleed off speed, but parachutes just work way better. I encourage you to experiment anyway. My goofiest creations are consistently the most fun.

[Laie]

Landing wheels are mass-less so they are "free". One radial parachute is 0.15 in mass

You're aware that you don't have to do a rolling landing, do you? The small gears are just as resilient when you plunge down on them.

(that said... whatever returns from orbit probably has an engine and a few drops of fuel left. A single parachute goes a long way, it doesn't take much of an engine nor much fuel to kill the remaining speed with thrust.)

I encourage you to experiment anyway. My goofiest creations are consistently the most fun.

So true.

[Empiro]

Has anyone actually experimented with spaceplanes on Eve? Even if you can't use jet engines, it seems like a space plane could still help in the following ways:

You can have have a lower TWR in your lower stage and save weight on engines.

You can ascend more slowly, and not lose as much due to drag / gravity losses.

[Laie]

Has anyone actually experimented with spaceplanes on Eve? Even if you can't use jet engines, it seems like a space plane could still help in the following ways:

It doesn't work that way. Using wings means that you are converting drag into lift. Like any such conversion, it's not without losses. Jet engines are so incredibly fuel-efficient that you can lose much, even most of your energy to drag and still come out with a net gain, because thrust from jets is so cheap to begin with. The very same fuel will provide more than three times as much thrust if you burn it in a jet rather than a rocket. Plus, a jet needs no oxidizer, so the real gain is more like tenfold (1).

If you have to run on rocket power (as on Eve), skip the shenanigans and go up as directly and quickly as possible.

(1) it should be noted that this is due to Kerbal Special Physics, or a programming error (depending on whom you ask). Either way, real-life jets aren't as efficient.

[Clockwork_werewolf]

You're aware that you don't have to do a rolling landing, do you? The small gears are just as resilient when you plunge down on them.

The beauty of wings is that you can still be going 80 m/s and yet only hit the ground at 20m/s. The vertical velocity is turned into horizontal velocity and that can be slowly dissipated after landing unlike vertical velocity. I also realise you might just be talking about using the wheels to land on like landing legs but they look weird like that, the role playing side of me feels a bit weird and they don't have half as much distance to compress.

[Laie]

I also realise you might just be talking about using the wheels to land on like landing legs but they look weird like that, the role playing side of me feels a bit weird and they don't have half as much distance to compress.

In terms of utility, the small gears are without equal. They have better suspension than any lander leg (never mind the short travel) and survive much harder impacts without any damage. All that at zero weight.

Usually, I don't abuse them either (it just looks silly, and lander legs aren't all that heavy and good enough for most purposes). One important exception is my heavy rover: no matter how many wheels I use and regardless of configuration, going over a bump at high speeds causes flat tires, which in turn causes lack of control. Small gears as the first axle absorb absolutely everything, keeping the actual wheels out of harm's way.