Ski-jump ramp for runway

[pheeph]

I suggest there be a ski-jump ramp placed somewhere on the runway so it makes things easy for planes to take off. A lot of planes and attempted spaceplanes I design tend to take off once they run off the other end of the runway. Of course, there's the risk the plane may not be straight by the time it reaches the end of the runway and possibly hit one of the lights on that end. A ski-jump ramp in the right place could reduce the chance of the plane veering off.

[DisarmingBaton5]

Landing would be difficult.

[Jordanpumah]

Landing would be difficult.

2 runways then?

[Jijonbreaker]

Considering the ramp would be at the end of the runway, if you haven't slowed down in time to not go off of it, you would never stop anyway. If anything, it's a little extra stopping power instead of going off the end.

[boomerdog2000]

And what about plane designs that work without a ski-jump but will clip it on their way up?

[minerman30]

And what about plane designs that work without a ski-jump but will clip it on their way up?

I think they mean something very shallow, with a rise of maybe 1 meter that's 15 meters long.

[MR4Y]

If none of you noticed, the runway is taller than the other paved roads on the KSC. And it's close to the sea, which makes the terrain after it a slope. The runway is already raised.

[Terran]

If none of you noticed, the runway is taller than the other paved roads on the KSC. And it's close to the sea, which makes the terrain after it a slope. The runway is already raised.

They're talking about a structure that would allow/assist a plane to pull up doing take-off, not about raising the whole runway. Something with a shape kind of like this, probably:

[sgtscuba]

Well have a look at the aircraft carriers, I think most of them have around 12 Degrees on the ramp. However, I see a flaw, does KSP take into account the effects that this has in real life (it increases lift as I recall, that why they used it for the harrier so it could carry more) aerodynamically? (i.e. increasing AOA give bonus lift?)

[vexx32]

Yeah, it does, afaik. Stuff like stalling angles and so forth don't exist in stock KSP, however.

[Kasuha]

I am pretty sure such ramp would make some aircraft designs crash.

The runway is already a ramp as it is, its end is elevated. Even planes with perfectly horizontal wings can take off from it. I think it's okay as it is.

[Roxette]

I think the runway just needs to be longer. The runway at the Kerbal space center is 2.5km long. The primary runway used for the space shuttle at the Kennedy Space Center in Florida is almost twice that length at 4.6km. The runway at White Sands, used for experimental flight, is 11km long. A runway of 2.5km would be considered inadequate for heavy widebody airliner use.

[Panzerbeard]

I think the runway just needs to be longer. The runway at the Kerbal space center is 2.5km long. The primary runway used for the space shuttle at the Kennedy Space Center in Florida is almost twice that length at 4.6km. The runway at White Sands, used for experimental flight, is 11km long. A runway of 2.5km would be considered inadequate for heavy widebody airliner use.

Kerbin is also much smaller than Earth, to the point that any runway of significant length is going to be affected by the curvature of the planet.

[Wahgineer]

Kerbin is also much smaller than Earth, to the point that any runway of significant length is going to be affected by the curvature of the planet.

Then curve the runway ever so slightly.

[LongHairedHuman]

I personally have no problems with the runway as it currently is. I usually tweak my planes until they take of at at least half the runway, or on brakes, if it's a vtol.

What really helps when doing this, is knowing why your plane won't take off, because the chance is quite low that your plane's take-off speed is reached at precisely the end of the runway. What's most likely the case is, is that you have your landing gear placed inefficiently. Try to place your main 2 wheels, so that they are right behind the plane's Centre of Mass. That way, when rotating, the plane has to lift less, as it will pivot around the Centre of Mass, rather than some point far behind it. Keep in mind that correctly placed landing gear will also result in smooth landings, as you won't slam down, but simply lower your nose as you slow down.

Combine this with a slight angle of attack, or trimming your elevators before take-off, and it should take-off like a charm. If, however, you can easily rotate your plane, but it won't fly, you simply don't have enough lift. Which can be resolved by adding more wing parts.

For more stuff on designing a plane, I found this guide:

http://forum.kerbalspaceprogram.com/threads/52080-Basic-Aircraft-Design-Explained-Simply-With-Pictures

[Kasuha]

Kerbin is also much smaller than Earth, to the point that any runway of significant length is going to be affected by the curvature of the planet.

KSP runway is perfectly straight - which makes it U shaped relative to the surface. That's why planes get moving towards the center of runway if deployed/standing at either end.

Making it curved would cause problems on edges between polygons approximating the curvature. Straight runway is so much better for smooth liftoff.

It's true that taken proportionally, KSP runway would be 25 km long on Earth.

[sgtscuba]

SNIP

So what your saying is we need something that displays thrust to weight and lift data?

[LongHairedHuman]

So what your saying is we need something that displays thrust to weight and lift data?

That would be handy, but I'm saying, if your plane has trouble taking-off, you might want to check if it's designed properly before requesting a ramp on the runway.

[Sauron]

KSP runway is perfectly straight - which makes it U shaped relative to the surface. That's why planes get moving towards the center of runway if deployed/standing at either end.

Making it curved would cause problems on edges between polygons approximating the curvature. Straight runway is so much better for smooth liftoff.

It's true that taken proportionally, KSP runway would be 25 km long on Earth.

Not quite true. While Kerbin is 1/10th scale, Kerbals and their spacecraft aren't. The Mercury capsule was about 1.8m in diameter compared to the 1-man pod's 1.25m. (Am I a bit sore that there still isn't a stock 1.25m 2-man pod? Yes. Yes, I am. )

[NWM]

Hey! This 2,5km long runway is more then adequate for my 400+tons refueling SSTO! If something cannot take of from this, then even the ski jump ramp won't help! It will only endanger the landing gears!

[Kasuha]

Not quite true. While Kerbin is 1/10th scale, Kerbals and their spacecraft aren't. The Mercury capsule was about 1.8m in diameter compared to the 1-man pod's 1.25m. (Am I a bit sore that there still isn't a stock 1.25m 2-man pod? Yes. Yes, I am. )

Relative size is not as important as other physical characteristics. Particularly takeoff distance. Not many real-world planes can take off on 100 meters, unlike many KSP planes.

[Sauron]

True, but that's in large part due to excessively powerful jet engines (and the associated ungodly TWRs), and a very unrealistic aerodynamic system that lets you make a flyable brick of wings.

In any event, the point was that the runway should be larger than 1/10th because parts (and gravity, thrust, etc.) are not also at 1/10th. We're actually on the same page.

[Deta]

the design is also used on aircraft carriers to help with shorter runway space, this is a good idea as more mass longer runway, look at recent news with airliners landing at places with short runways, they have to lighten the plane before it can take off again.

maybe at the end where we are dropped could have blast plates that come up behind plane to increase thrust.

[iamaphazael]

If the problem is that OP's planes don't lift off until they drive off the edge of the runway, why would putting a ramp at the end of the runway make any difference? You'd still have to taxi all the way to the end of the runway before getting airborne. Making the runway longer also isn't the solution (the scaling question being entirely irrelevant). Most craft I've seen get up to their max speed after about 1/4 the length of the current runway. Making it longer won't make it easier to take off, it'll just increase the distance you need to roll before you get to the edge of it and end up in the air.

If the OP wants to be able to take off from the middle of the runway instead of the end, all they need to do is move their aft landing gear forward so they're closer to the center of mass of the craft

[Kasuha]

I find this request particularly funny because not so long ago there was a flamy discussion where OP required the runway lights to be removed because his planes were hitting them every so often.

Now imagine what would happen if such a ramp was really at the end of runway and one such large and heavy plane got near it.

First of all, the plane would already be in horizontal motion and its mass momentum would try to keep it in straight movement. The undercarriage, on the other hand, would try to follow the shape of the ramp, ramming hard into the body of the plane. The situation would not be significantly different from a heavy landing.

Next, assuming the plane would not snap under such load, it would inevitably slow down somewhat as its horizontal speed is partially transferred to vertical with gravity going against that.

After that, the plane's front wheels would pass the edge of the ramp. Assuming the plane does not yet have sufficient lift (because if it has, it doesn't need the ramp anyway) its front would start to fall towards the surface, while its rear wheels are still lifted up by the ramp.

When the plane's rear wheels pass the ramp edge, the plane already has certain angular momentum turning it against the ground.

All in all I think it is easier and safer to lift off without any ramp because there's less strange effects that await you when you exceed the end of the runway as it is.