How to land giant planes?

[Spacetraindriver]

I like big things. So I make big planes. The problem is that they blow up upon landing. I'm planning to build an An 225 but if I can't land a 747 then these crafts are just flying eye candy. Just tips. I am not cutting throttle because I know that would slow the monsters too much and land with a devastating thump followed by a bunch of explosions. It's not just MK3 planes (though the majority) but just any plane that is of size.

[MaverickSawyer]

What explodes first?

Do you have any screencaps of these monsters?

[Coga19000]

Depending in the wing area of your planes, cutting throttle should not slow your craft to the point of stalling, at least not immediately. And it may also be the size of your landing legs that's causing the problem ; try some larger sizes.

[Spacetraindriver]

Yup

WARNING LOTS OF BIG PICTURES:

f3 says that there is a structural linkage failure on everything.

[FlipNascar]

Edit: Probably because you're smacking the runway too hard. What's the mass of the craft and have you tried having the landing gear attached to the fuselage rather than the wings, and maybe consider adding more landing gear if needed.

TLDR: Reduce vertical speed. Most likely culprit.

It's difficult to know from your text if it's design or pilot error... However, practice, practice and practice. Ubung macht dem meister! And, you'll need to maybe make some design changes to allow for the behemoths to come back down again. Pitch control will be you friend. Double up control surfaces if you have to. If it's only cheating if you're a pedant that likes explosions.

In principle landing a plane is relatively simple and ignores the size. Of course KSP, size matters. The bigger it is, probably the floppier it is... Fly it to the start of the runway as slowly as you can. Make sure you still have pitch authority. As you approach the ground, bring the nose level. If you were to see this from a real cockpit this is where you'd look at the end of the runway and try to keep the aircraft up in the air as long as possible. Wait for the ground to meet you. An exercise that will help you with this is to start with a smaller aircraft and just try to fly it as slowly as possible just above the ground. Sadly I don't think KSP models ground effect. But you'll be surprised at just how slow you can go.

And don't forget, the bigger it is, the gentler you must be with it. If you can reduce the vertical speed, chances are you'll survive touchdown.

Edited September 6, 2015 by FlipNascar
Ninja'd

[Spacetraindriver]

All craft use two largest gear sizes.

- - - Updated - - -

Sometimes I go slow, don't stall, and still! Kaboom!

[RocketPilot573]

Try attaching the gears directly to the fuselage, you may be surprised how much that can help, and/or just add "moar wheels!" like I did:

Also, you should not be landing at more than 80 m/s speed, if the plane falls too fast going any slower then add more lift, either in the form of larger wings or flaps.

[Spacetraindriver]

Most craft of my craft have MANY landing wheels on fusalage, But thanks for landing Adivice!

[JTpopcorn]

The joint reinforcement mod might help. Also set up control surfaces as flaps to reduce speed. Most likely smashing the front.

[Chaos_Klaus]

If you need more lift, you can angle the main wing upwards a little. You should toggle the flaps for landing to get even more lift.

You should *definately* cut thrust for landing. How do you expect to stay on the ground with the same thrust that makes you lift off? Remember: Landing is just controlled crashing.

[peachoftree]

The joint reinforcement mod might help. Also set up control surfaces as flaps to reduce speed. Most likely smashing the front.

^this. MK3 joints are disproportionately weak for their size, leading to them being prone to structural failure. IMHO, KJR is essential for any MK3 plane

-edit-

500 posts!

Edited September 6, 2015 by peachoftree

[ForScience6686]

I can't tell by the pictures but you should have a lot of flaps on those. I would guess if the plane can make it down the runway, then you should be able to safely put it on the ground. Take the time to find the low speed flight characteristics of each plane.

[Spacetraindriver]

Oh forgot her.

[Captain H@dock]

I don't think you can land that last one... From the screenshot, it seems you barely made it off the ground at 180 m/s (and used the slope at the end of the runway to rotate a bit).

Looking at your Angle of Attack at 200 m/s (it seems to be something like 4 or 5 degrees), you won't be able to flare at anything under 100 m/s... Also you are applying full elevator and don't seem to pitch much... If you have so little pitch authority at 200 m/s, you are going to have a bad time at approach speeds....

I can land mk3 planes with a single set of airliner wing in the 50-70 tons range with no flaps, and occasionally 100 tons ones, but this is REALLY tricky. You have to touch down with almost zero vertical speed. When in IVA, look at the VSI indicator, the needle needs to barely be under the 0 line. Anything higher than 2 m/s vertical speed and the mk3 joins will break (exact value depends on the number of joints and on the total weight of the plane). Mk3 contraption are just really weak. But even in the real word, landing maximum weights are lower than take-off maximum weight.

At any rate, you better practice on the grass near the runway first. Chances are you will spend a lot of time in the flare, so you are better off with a 20 km runway (or whatever is the length of th KSC grass area).

I can post a "training" 50ish tons mk3 plane later today if you want to practice with something doable, because some of your crafts seem like they won't ever land safely... (if takeoff is tricky, don't even think about landing before emptying the tanks)

[Spacetraindriver]

I don't think you can land that last one... From the screenshot, it seems you barely made it off the ground at 180 m/s (and used the slope at the end of the runway to rotate a bit).

Looking at your Angle of Attack at 200 m/s (it seems to be something like 4 or 5 degrees), you won't be able to flare at anything under 100 m/s... Also you are applying full elevator and don't seem to pitch much... If you have so little pitch authority at 200 m/s, you are going to have a bad time at approach speeds....

I can land mk3 planes with a single set of airliner wing in the 50-70 tons range with no flaps, and occasionally 100 tons ones, but this is REALLY tricky. You have to touch down with almost zero vertical speed. When in IVA, look at the VSI indicator, the needle needs to barely be under the 0 line. Anything higher than 2 m/s vertical speed and the mk3 joins will break (exact value depends on the number of joints and on the total weight of the plane). Mk3 contraption are just really weak. But even in the real word, landing maximum weights are lower than take-off maximum weight.

At any rate, you better practice on the grass near the runway first. Chances are you will spend a lot of time in the flare, so you are better off with a 20 km runway (or whatever is the length of th KSC grass area).

I can post a "training" 50ish tons mk3 plane later today if you want to practice with something doable, because some of your crafts seem like they won't ever land safely... (if takeoff is tricky, don't even think about landing before emptying the tanks)

Oh that's a screenshot of the test version, though I think you are right...

[Merandix]

Take your time! I use runway markers (flags or a small rover). I generally want to be lined up with the runway at ten kilometres out. It takes practice, but you basically approach low and slow.Land with very low vertical speed. You achieve this by taking the time to land, and not dropping in like a brick from 10 km in altitude.

Edited September 9, 2015 by Merandix

[Dobelong]

Recipe for disaster Big planes that land:

 

20 cups of struts

40 teaspoons of LY-99 landing gear

1 plane

for a little extra zest, fit on a few parachutes and airbrakes.

[Wanderfound]

On 8 September 2015 at 10:26 AM, Merandix said:

Take your time! I use runway markers (flags or a small rover). I generally want to be lined up with the runway at ten kilometres out. It takes practice, but you basically approach low and slow.Land with very low vertical speed. You achieve this by taking the time to land, and not dropping in like a brick from 10 km in altitude.

Seconded.

The key to tricky landings is to set up your approach as low, slow and shallow as possible. Get down to a few hundred metres of altitude while you're still several km out, slow down to the minimum possible speed at which you can maintain level flight, and gradually ease it down so that you're at most twenty metres off the deck as you cross the end of the runway. Don't be afraid to wave off and go around again if the approach doesn't feel right.

Practice with smaller ships first; see if you can get it so that the lip of the runway just grazes your wheels while you're flying level at extreme low altitude. Repeated touch-and-go landings (i.e. throttle up and take off again as soon as your wheels contact the ground) are good practice as well.

[Stoney3K]

I can see a few problems with your craft: Too little lift, badly placed landing gear and too high a V/S on landing.

If you need >100 m/s for your craft to take off, then your craft does not have enough lift for the attitude it is flying at. Try cambering the wing slightly using the Rotate tool in the SPH, that will give the wing more lift even if you are flying straight and level. By default, straight and level flight means no lift if the wing is completely horizontal.

Adding more lift for maneuvering like takeoff and landing means adding flaps. Basically you add control surfaces to your wing which will give your wing some additional curve when you need it. To do this, add control surfaces (like the Big-S Elevons or the FAT control surfaces) and set them to deploy via an action group.

Gear placement is also important. You want the gear to be slightly behind the CoM of your plane, on both takeoff and landing. If the gear is in front of the CoM, your plane will see-saw when you hit the ground and destroy the tail. If the gear is too far away from the CoM, it becomes difficult to take off and when landing, you will slam into the ground with no way of controlling your stop.

If you land properly, you should be able to keep the nose gear *slightly* above the runway when the main wheels touch down, and ease the nose wheel down by tapping the brakes. For aicraft that come in fast, use the airbrakes on the runway to slow them down.

One golden rule in flying aircraft is also important: PITCH controls SPEED, while THROTTLE controls DESCENT. If you're too high, throttle back. If you're too fast, pitch up.

Edited December 27, 2015 by Stoney3K

[mattssheep4]

SmartS answer: carefully. Else: everyone else who commented has been far more helpful than I'll ever be