is this a plane or a rocket?

[lukeoftheaura]

Is this a plane or a rocket?

http://forum.kerbalspaceprogram.com/threads/100489-Scythe-Mk5-Light-SSTO-Dropship

I want to use this in a "best of community crafts" video on Utube, but Is it a rocket, or a plane?

Edited November 22, 2014 by kerbingamer376

[Red Iron Crown]

There's a lot of overlap between "plane" and "rocket". I would consider that particular craft more of a rocket, as it doesn't depend on wings or other aerodynamic devices to stay aloft, it instead relies on thrust. Though even that is a bit of a misnomer as much of its thrust comes from jet engines rather than rocket engines. I like to use the term "hybrid" for craft with mixed propulsion systems like this one's jet/rocket mix, so I'd probably call it a "hybrid VTOL" rather than a plane or rocket.

[lukeoftheaura]

There's a lot of overlap between "plane" and "rocket". I would consider that particular craft more of a rocket --snip-- I'd probably call it a "hybrid VTOL" rather than a plane or rocket.

Oh ok. thanks for that.

[Alshain]

I'd call that a jet assisted rocket. I'm not sure there is a strict definition but in my mind a planes must

1. Have wings.

2. Use those wings as a primary source of lift.

A rocket can have jet engines, and it can have winglets, but the engines do not make a plane and winglets are just used for steering and control, not lift.

[capi3101]

Difficult to say. If it has to be one or the other, I'd go with which launch platform it uses - call it a plane if it takes off from the runway and a rocket if it takes off from the launch pad.

And even then, Red Iron Crown's "hybrid VTOL" suggestion is probably better.

[Alshain]

Difficult to say. If it has to be one or the other, I'd go with which launch platform it uses - call it a plane if it takes off from the runway and a rocket if it takes off from the launch pad.

That doesn't fit well either, as most consider the STS, the Buran, and the Dream Chaser to be Spaceplanes... all rocket launched.

[Pecan]

I'd call that a jet assisted rocket. I'm not sure there is a strict definition but in my mind a planes must

1. Have wings.

2. Use those wings as a primary source of lift.

A rocket can have jet engines, and it can have winglets, but the engines do not make a plane and winglets are just used for steering and control, not lift.

That's pretty definitive, I would think. A plane uses wings for lift whereas a VTVL/JATO rocket may use winglets, but almost purely for guidance.

[The_Rocketeer]

I'm gonna go with... plocket.

More seriously, not all spacecraft in KSP (or real space) are necessarily rockets or planes. A rocket is, definitively, powered by a rocket engine. An aeroplane uses fixed wings for lift and jet (or propeller) engines for thrust. A craft that uses Ion engines, for example, isn't a plane or a rocket.

Turning to National Socialist Germany may provide the precise answer... (NOT the final solution... [sorry]).

There's no wing as such in that design, but since those fuel tanks create lift you could argue that they count as aerodynamic surfaces, making this craft similar to the Horten Ho 299 "flying wing".

In that case what you actually have is a rocket plane. The Nazis again give us a good example - the Messerscmitt Me 163

Edited November 20, 2014 by The_Rocketeer

[Alshain]

There's no wing as such in that design, but since those fuel tanks create lift you could argue that they count as aerodynamic surfaces, making this craft similar to the Horten Ho 299 "flying wing".

I think someone is splitting hairs. The Horten Ho 299 had wings, they were just built in near seamlessly to the body and contained fuel. Not all that much different from the Northrop Grumman B-2 Spirit, which also had wings.

[Vallius]

Maybe this is why someone coined the term Aerospace Engineering--covers all the bases here.

[The_Rocketeer]

I think someone is splitting hairs. The Horten Ho 299 had wings, they were just built in near seamlessly to the body and contained fuel. Not all that much different from the Northrop Grumman B-2 Spirit, which also had wings.

Hardly splitting hairs, just because the tanks don't look like wings it doesn't mean they don't perform like wings as far as the game is concerned. Lift, after all, is lift.

[Alshain]

Hardly splitting hairs, just because the tanks don't look like wings it doesn't mean they don't perform like wings as far as the game is concerned. Lift, after all, is lift.

But they don't perform like wings, at least not in the way that craft is built. Anything falling through the air will have some kind of lift (in the real world), but that doesn't make a football a plane.

It's not about how they look, the lift on those adapters is insignificant, it clearly flies on thrust alone and if there was no lifting body effects on it, it probably wouldn't fly much different. That makes it a rocket or maybe a hovercraft, a pretty neat one too, but not a plane.

[Slam_Jones]

I built a "plane" that was actually just an SRB with a external chair and some wings on it. It even made for a pretty d*mn decent glider once the fuel ran out.

[The_Rocketeer]

But they don't perform like wings, at least not in the way that craft is built. Anything falling through the air will have some kind of lift (in the real world), but that doesn't make a football a plane.

No, in RL aerofoils generate lift. Anything else simply generates variations on drag.

A football isn't an aerofoil, so it's not a wing. It also doesn't have an engine, so it's not a plane.

However, we're in KSP, where 'lift rating' = lift. Any part with a lift rating basically counts as a wing as far as the game's calculations are concerned. Move them forwards fast enough and they generate an upward force. That's really all that matters.

[Alshain]

No, in RL aerofoils generate lift. Anything else simply generates variations on drag.

A football isn't an aerofoil, so it's not a wing. It also doesn't have an engine, so it's not a plane.

No, Airfoils are a more efficient way of generating lift. Anything with an angle of attack can generate lift, including the football, but more to the point, a rocket body. So by your definition the Apollo rocket is a plane, it had engines and also had lift. Pretty much anything man has ever put in air the that uses engines is a plane by your definition, a hot air balloon for example. The side of that balloon will create lift as it travels through the air, not much but it's there. (I'm not referring to the rising heat effect here).

Edited November 20, 2014 by Alshain

[The_Rocketeer]

No, Airfoils are a more efficient way of generating lift. Anything with an angle of attack can generate lift, including the football, but more to the point, a rocket body. So by your definition the Apollo rocket is a plane.

Hmm... having updated my definitions, I accept your point about lift and AoA (although since lift is simply a variation on drag anyway I wasn't really 'wrong').

However, in KSP parts with a lift-rating are the only parts that generate this force, regardless of shape or AoA. Any other part will only generate aerodynamic drag. So, if you want to make ANY plane, you'll need to use some of these parts. Given how physics works in KSP, I don't see any reason to differentiate between one lift-generating part that's flat and winglike and another lift-generating part that's lumpy and tank-shaped, except for pure aesthetics (and the fact that some are more efficient than others).

I don't think my definition suggests anything about the Apollo rocket (sometimes called the Saturn V), except that it isn't a wing and therefore not a plane. In KSP, the Saturn V wouldn't generate lift because it (presumably) wouldn't have any parts with a lift-rating.

I don't see any reason to argue further. You're taking a pretty narrow view of what counts as a wing, I guess based on whether it looks like a wing or not, and I'm basing my somewhat-broader view on whether it is capable of generating lift in KSP. Considering the various peculiar contraptions KSP has given rise to, I think that's pretty fair - it's a matter of what can be done.

Edited November 20, 2014 by The_Rocketeer

[TinfoilChef]

I think I'd just split the difference and aim for a bit of funny and call it a "Pocket" (Plane Rocket)

[CavemanNinja]

Personally, I think these fit under a newer category of vehicle, a "hypothetical long-range wingless VTOL", simply because they're propelled by a compound of both plane and rocket propulsion systems. An over-powered hovercraft, if you will. I think you're all thinking in the wrong way here, applying it to RL, because this would be extremely awkward to do in real life, because of planet difference sizes and the weight of rocket fuel, ergo jet engines never even coming close to pulling along rocket engines and fuel capable of making orbit, dropped jets or not.

Of course, this is just my humble opinion and nothing should be taken personally

Edited November 23, 2014 by CavemanNinja