Biplane Spaceplanes?

[Lego_Prodigy]

So I was researching in my aviation books for design ideas from real aircraft/spacecraft, and I suddenly realized that none of the spaceplanes that Ive ever seen from real life were biplanes. Is there a reason behind this? I know that the first biplanes were extremely draggy from almost everything, but Im referring to a sort of more modern material biplane. Would that work at all in things like reentry?

[Vanamonde]

Lift is relatively unimportant for an SSTO, as wings only lift significant weight at lower altitudes where the air is thicker. At higher altitudes, they create drag and add weight while contributing little to getting the craft up there. Concentrate on getting up to speed and only utilize enough lift to get off the ground. 

[Gargamel]

2 hours ago, Lego_Prodigy said:

I suddenly realized that none of the spaceplanes that Ive ever seen from real life were biplanes.

I'm actually drawing a blank on real life spaceplanes, I'd like to see some.  And by space plane I mean a plane, not a vertically launched glider (ie shuttle). 

2 hours ago, Lego_Prodigy said:

I know that the first biplanes were extremely draggy from almost everything, but Im referring to a sort of more modern material biplane.

The materials really don't matter, as the wings themselves are the cause of the drag.    Biplanes were required because of the weaker engines, hence slower air speed, which required more lifting area. 

 

[bewing]

Some people build spaceplanes with more wing area, some people with less. It's a matter of taste and flight profile.

For those spaceplanes with larger wing areas, there tends to be a limited amount of space to hook the wings to, on the side of the fuselage. So those kinds of spaceplanes often have multiple wings. But since the game does not care about wing clipping, most builders clip all the wings together so that it looks like one wing. It's still technically a biplane, or triplane, or whatever.

[Xd the great]

The short answer is because spaceplanes handle high heat/pressure during reentry, so they use strong materials. The advantage of biplane is to reduce wing length of each plane, so that isnt a  concern on spaceplanes. However, having two wings means that you have more drag and are generally less stable at higher speeds, so spaceplanes are never biplanes.

The long answer is because it does not look cool and modern enough for spaceplanes to have 4 wings.

[Gargamel]

3 hours ago, Xd the great said:

The long answer is because it does not look cool and modern enough for spaceplanes to have 4 wings.

Doesn't get much cooler than this. 

[Xd the great]

Well, the x wing is theorectically unflyable in atmosphere, because of the wings in the back.

Assuming that the plane is uniform.

Plus i am talking about real life stuff lol

[Klapaucius]

2 hours ago, Xd the great said:

Well, the x wing is theorectically unflyable in atmosphere, because of the wings in the back.

Assuming that the plane is uniform.

Plus i am talking about real life stuff lol

I always figured the wings were just extensions for the guns anyway. Everything in Star Wars has anti-gravity, so I don't think of them as lifting surfaces. They are not exactly airfoil shaped either. 

[Lisias]

3 hours ago, Xd the great said:

Well, the x wing is theorectically unflyable in atmosphere, because of the wings in the back.

Assuming that the plane is uniform.

Plus i am talking about real life stuff lol

I beg to differ. :-)

 

[steve_v]

On 6/3/2018 at 11:42 AM, Lego_Prodigy said:

Is there a reason behind this?

Because IRL biplanes are too draggy, and the interaction between the two sets of wings at supersonic speeds vastly complicates the design process.
It's not impossible to build a supersonic biplane, it's just extremely difficult to design one that is efficient and stable at a range of supersonic / hypersonic speeds. Monoplanes are simpler, stronger, easier to design, (usually) less draggy, and don't require the finicky wing-interaction tuning.

In KSP this is all irrelevant, because the aerodynamic model sucks. It's a bit more realistic if you run FAR, as some of these effects are simulated and the shape of the craft (and wing) actually matters for drag...

[Scarecrow]

My bi-plane spaceplane manages to get to orbit quite happily, though it doesn't glide too well and landing can be a bit dodgy.

[Lego_Prodigy]

Stop posting X-Wing pictures, I have seen all the movies and have a star wars side too, but I DID NOT ask for lots of X-Wing pictures. X-Wing's S-Foils are NOT for any lift, as seen in some of the above images.

 

[Lisias]

4 hours ago, Lego_Prodigy said:

X-Wing's S-Foils are NOT for any lift, as seen in some of the above images.

But it works nevertheless. Once you get the ideal angle between the Wings, the thing became very stable and maneuverable.

The thing is.. It works! Even on "real-life", there're some guys making flying models on it. Every single one of them had to reach some compromise in order to make the thing stable. Mine was to use sweep wings: the CoM is exactly between the two ailerons.

And it make turns like a charm. :-)

[Gargamel]

18 hours ago, Scarecrow said:

My bi-plane spaceplane manages to get to orbit quite happily, though it doesn't glide too well and landing can be a bit dodgy.

Especially in swamps.   

13 hours ago, Lego_Prodigy said:

Stop posting X-Wing pictures, I have seen all the movies and have a star wars side too, but I DID NOT ask for lots of X-Wing pictures. X-Wing's S-Foils are NOT for any lift, as seen in some of the above images.

You asked about bi plane space planes (in particular mentioning IRL, which I'm still waiting for some examples, I'd love to see some! (not being 'mean' here, I'm genuinely curious)), the conversation was assumed to pertain to KSP bi plane space planes, and the argument was mentioned they don't look cool.  Which was countered by multiple examples of cool looking biplane space planes.   What the OP asks for, and where the thread goes, don't often have the same path. 

Edited June 5, 2018 by Gargamel

[Daniel Prates]

On 6/5/2018 at 12:33 AM, Lisias said:

The thing is.. It works! Even on "real-life", there're some guys making flying models on it. Every single one of them had to reach some compromise in order to make the thing stable. Mine was to use sweep wings: the CoM is exactly between the two ailerons.

And it make turns like a charm. :-)

Could you post a picture of this thing, from the SPH,  showing the CoL and CoM? I am curious as how you managed to place the CoM behind the CoL.

[Lisias]

6 hours ago, Daniel Prates said:

Could you post a picture of this thing, from the SPH,  showing the CoL and CoM? I am curious as how you managed to place the CoM behind the CoL.

By carefully (and not so honestly) trimming the fuel tanks and use fuel-less fuselages .. :) The Droid is a fuel tank!

On the "cheat" version, I shamelessly edit the fuel tanks capacity directly on the CFG file (it crashes Kerbal-X due this).

Below, two versions from the same craft.

And another screenshot from another angle. You can see that my CoL is slightly below the CoM (not really a problem, so I didn't fix this), but the CoT is aligned to the CoM - so the thing is maneuverable on space:

I used Vernour RCS, so I could save the Monopropellant space. And since the thing is a fighter, she could use the extra punch.

Edited June 6, 2018 by Lisias
added a screenshot

[Daniel Prates]

Damn!  It works!

[Lego_Prodigy]

Sigh, Its not helpful when I can barely land something you guys post, and even worse when you admit to that.

[Lisias]

The OP was talking about flying, not landing!

Of course, I have some other designs for X-Wing. One for hypercruise, other for take-off/landing, another for dogfight. I'm still figuring out a good one for reentry. 

Once I manage to stabilize all the possible configuration, it's time to try Inferno Robotics to built the final version. With more 'sensible' engines from some AddOn with good SyFy parts (assuming I don't make my own).

This is what KSP is about.

[mikegarrison]

The real purpose of biplanes is/was twofold.

1) Structural strength. Back in the day, airfoils were very, very thin. So the structure to carry the wing loads couldn't always fit inside. And with fabric skins, the skins couldn't carry the loads either. So truss-type structures were used, and that worked well with biplanes.

2) (related to 1) Wing loading. A biplane has twice as much wing area for the same planform, so it has half the wing loading (lift/wing area). This eased the structural requirements. Also,planes with low wing loading tend to be slow but maneuverable, which was handy for the early WW1 fighters.

The combination of structural strength and lower wing loading is also why many modern acrobatic airplanes are biplanes.

However, for high speeds you tend to want very small wing areas and very high wing loading, leading to airplanes like the https://en.wikipedia.org/wiki/Century_Series A spaceplane obviously has to be designed for very high speeds.

[Scarecrow]

I've tweaked my X-Wing since posting, so it's not as difficult to land now.

[Lisias]

3 hours ago, Scarecrow said:

I've tweaked my X-Wing since posting, so it's not as difficult to land now.

You can save the airbrakes by using the ailerons as breaks. On my design, the inner ailerons are deployed when you hit break - the lower ones inverted from the upper ones. Looking carefully, you will find 3 sets of ailerons per wing (one is under the engines). 

[Scarecrow]

Reducing speed wasn’t the problem. Ever since whichever patch it was where they messed with the landing gear I’ve consistently struggled to assign settings to the gear that allows craft to track straight when taking off and avoid excessive bouncing when landing. 

[Lisias]

Bouncing is good. It means you didn't explode yet!

Edited June 10, 2018 by Lisias
Typo

[Andetch]

So to try out @Lego_Prodigy's question I just did a 5min build of an SSTO spaceplane (bi-plane). It worked, I even "landed" back at ksc. (I put landed in quotes because on hitting the runway the craft slewed across then flipped onto it's back).

Had a few issues with stability, but I think they were mainly due to the poor build quality as I rushed it (things like not enough air intakes so some of the engines flamed out, and as I was using rapiers I forgot to turn some off auto switching etc, but I recovered). So in answer to the OP, yes it is possible in KSP.

To the best of my knowledge, in reality there are no SSTO spaceplanes. Only things close are the Shuttle/Buran, the X35 thing the US military uses (all launch vertical and glide) and Virgin's Spaceship Two (launched from a carrier plane) and none are SSTO.

https://imgur.com/a/V12TbY5

 

 

 

Edited June 25, 2018 by Andetch
Images