Are there any existing (space)plane landing tutorials?

[Jovus]

So I've done a lot of reading about how to build planes, and I daresay I have a decent, if not absolute grasp on the basics of the subject. I can get my planes to take off. I can trim them and fly straight, or turn about, and with some even do loops - all with or without SAS (though with is usually easier, of course).

What I can't seem to do is land them on the runway. (I can fairly often land somewhat near the runway, on the beach or the grasslands beyond.) I end up either overshooting and having to fly back, or dive-bombing the runway with predictably hilarious results.

To that end, are there any tutorials in existence for how to land your plane? I understand that much of the answer depends on the individual airframe, but are there some broad guidelines on approach profiles I should be looking for? For example, if I'm 1km laterally away from the runway but 5km up and moving at 200m/s, I know I'm definitely flying back for another pass. Are there any tips for how to get those approach profiles?

Thanks in advance!

(FYI, I'm using FAR and DR.)

Edited August 21, 2014 by Jovus

[Warbird]

Generally you want to kill off as much of your speed as you can and still remain in the air and then come in rear wheels first. KSP's aerodynamics are weird as are FAR's in some aspects. The best way to get good at landing is to just practice it, quicksave a klick or so out and try landing until you get to where you can consistently hit your target. You are using your brakes when landing, right?

[Scarecrow88]

I found experience counts for a lot, as you learn to judge when things are lined up nicely and when they are not.

A simple guide to help you get things lined up would be to plant a flag a couple of hundred of metres off each end of the runway. When landing, set the nearest flag as a target, and keep your nose pointed at the pink target marker on your navball. At the same time you should be aiming to keep the two flags lined up vertically. This latter action means you are in line with the runway, whilst the former is designed to have you aiming at the near end of the runway.

[Jovus]

I figure I'm going to have to put in 10-20 hours of solid practice to actually consistently land without exploding or waving off until I get impatient (at which point, see previous). My problem so far hasn't been lining up over the runway - it's been coming down fast enough without doing it too fast once I have.

Thanks for your suggestions, though. The flags will be especially helpful when I'm trying to figure out how to get down after a Mun run (presuming I ever get there).

[G'th]

An easy way to land is to just fly in descending circles around KSC until your speed drops to around 100-150m/s and your altitude is about 1000-3000m. From there, just fly out past the runway towards the ocean or the mountains, turn around, and then glide in for landing. Keep your plane pointed just above the horizon (so that you descend but don't gain speed) and you should be able to make a nice, smooth landing.

[Pecan]

I think there are two different aspects here that can conveniently be tackled separately; landing itself and reentry-to-flight.

With any particular design you'll need, if not want, to test-fly it with circuits and bumps - just seeing how it takes off, handles in the air and will (or won't) land. In general you need to be descending at less than 10m/s and want to be going as slowly as possible horizontally. Ideally you land just above stall-speed so the first thing to find out is how slowly the plane will fly without falling out of the sky! You now have the approach speed... Knowing the approach speed you'll also have found out what the descent rate is at that speed. "Normal" landings call for a 'flare' just before you touch down - pitch-up to reduce descent and stall onto the runway - so the plane stops flying. If you can't flare to a comfortable landing you'll want to come in 'hot' - that is, use a bit more throttle for a shallower approach so you land a bit faster but don't have to pitch-up so much to slow down your descent. (Too hot and pitching-up will just make you climb again). This can all be practiced from takeoff and flying around and around KSC.

Separately you'll have to find out how the plane handles de-orbit and transition to normal flight. The only thing I can suggest there is picking an initial impact point about 10-20km before your target and then pitching-up in flight to avoid the impact and fly to the intended destination. DREC will force a more shallow re-entry trajectory but in any case don't attempt to control the plane in atmosphere but anywhere near orbital speed - the drag will either flip and spin it or destroy it outright. Wait until you're 10km or lower altitude and 200m/s or less velocity.

NavUtils is a HSI/ILS system mod that might make this easier for you. It certainly makes it more interesting (I like instruments, what can I say ^^).

[Guest]

Something to keep in mind is the fact that a plane that carries enough fuel into space in order to reach the Mun will handle a whole lot different with empty tanks on return than it did with full tanks on takeoff. One of the things I have had problems with is actually keeping the nose down when landing because of the heavy engines in the back.

[Wanderfound]

http://forum.kerbalspaceprogram.com/threads/52080-Basic-Aircraft-Design-Explained-Simply-With-Pictures?p=1310540&viewfull=1#post1310540

The one thing I didn't mention there: vertical velocity is much more important than horizontal velocity. Excessive horizontal velocity is only a problem if you run out of landing strip; it's entirely possible to touch down safely at 200m/s (although 100m/s is better). But if your vertical velocity is much over 5m/s or so, you're going to crash rather than land. Come in as shallow as you can.

Edited August 21, 2014 by Wanderfound

[RexKramer]

When you are approaching the runway, the visuals lead you to believe your approach is shallower than it actually is. If you are overshooting the runway, adjust your path next time to be much shallower.

Providing you still have jet fuel, a low, shallow, stabilized approach is an easy way to get on the runway.

You also shouldn't need much throttle during the approach- just enough to keep a little speed. The right speed will depend on the design, but most planes seem to fly fine at 80-120 m/s when below 2,000 meters.

[Geschosskopf]

What I can't seem to do is land them on the runway. (I can fairly often land somewhat near the runway, on the beach or the grasslands beyond.) I end up either overshooting and having to fly back, or dive-bombing the runway with predictably hilarious results.

I'm assuming you're just interested here in how to use the game interface to make your plane hit the desired point on the ground, rather than the technicalities of how to build the thing. So here's what works for me.

First off, hit V to get the camera into FREE mod. Some folks recommend CHASE instead but FREE works better for me. Then rotate the camera until it's directly behind the plane far enough away that the wingspan is about 1/2 to 2/3 the width of your screen, and slightly above the axis of the fuselage. This is so you'll be able to see your shadow on the ground easily, as that shadow is your main thing for judging your vertical speed and distance from the ground.

Second, turn the lights on. If you're using the normal Small Gear Bay landing gear and have attached them in the default orientation, they'll have landing lights shining down and forward when the gear is down. In addition, I recommend attaching Illuminator Mk 1 floodlights under the wings, facing forward and rotated upwards 3 ticks of the SHF-W key so they're almost, but not quite, pointing straight forward. The lights are very handy even in daylight to tell you when you're getting near the ground, especially if you can't see your shadow yet (as is often the case when landing N-S out in the field or on another planet, or landing E-W when the sun is low in the sky).

Then it's just a matter of spotting and lining up with your landing site (runway or otherwise) from as far away as possible and throttling back, flying the plane to the ground. What you do is once you've spotted your landing site, throttle back as far as you can without stalling so by the time you get to the runway or a bit before, you'll have slowed down as much as possible. Then guesstimate the angle from your plane's altitude down to the landing site and adjust your elevators as needed so your prograde marker is that far below the horizon. This will put your on a glide path that will intersect the ground in the vicinity of the end of the runway (or whatever else you want to land on). Then just sit back and let the plane drift on down, only making occasional adjustments to pitch and throttle as needed to stay on the glide path.

You should now be near the end of the runway just above your minimum flying speed. You should be starting to see your lights shining on the ground ahead and below, and might be able to see your shadow as well. If you haven't already, chop throttle to the absolute minimum to prevent a stall or shut it all the way off. Then make your final adjustments to the controls to make sure you hit the runway where you want to (you should be aiming for some striped bars or the numbers). As you get very close to the ground, you'll definitely see your shadow so can easily tell exactly how high you are and how fast you're descending. Flare just before you wheels meet your shadow, make sure all wheels are on the ground, then hit the brakes (and zero throttle if not already). That's pretty much it.

[EdFred]

I'll take what I teach with my real life students for final approach (no, I don't fly space planes, but I am a flight instructor) and try and modify it a little for KSP:

Set up for a long final approach and you only need to worry about 3 things

#1 Runway alignment

#2 Approach path (glide slope)

#3 Approach speed

Unlike Geschosskopf, in KSP I prefer chase mode, and I set up my camera so I am just above and behind the plane.

With runway alignment, just make sure the runway is a straight line in front of you. It doesn't angle left, it doesn't angle right. The ends of the runway should be vertically aligned in your sight picture. If the far end of the runway is left of the near end, you are left of path, and need to turn right. If the far end is right of the near end you are right of approach and need to turn left.

Once lined up with the runway, the trick with the approach path is to pick out a spot on the runway to use as your aiming point - usually the numbers or the aiming markers (the large white blocks) - and keep it in the same spot on your screen. Maybe an inch (2.5cm) or so above the nose of your plane. If the aiming point starts to rise up in relation to your plane, you are starting to get below your approach path. So you need to climb a little (add a little power when you do). If the aiming point starts to sink in relation to your plane, you need to descend a little (reduce the power a little here). If you keep that point stationary on your screen, you are good to go.

How fast should you be flying your approach? A good rule of thumb would be see what speed you take off at (assuming you've designed your plane to not use the entire runway on takeoff) and add 20% to that.

Once you are over the end of the runway, reduce throttle to zero, and slowly start to raise the nose of the aircraft. If done correctly, you will still descend, your speed will reduce, and you will touchdown just like you are supposed to.

This is (roughly) what I teach in real life in real planes. Funny thing is, it's actually easier in real life.

Edited August 21, 2014 by EdFred

[Kerolyov]

Even though I've had KSP for 18 months must admit I've not done much with planes and always when I did I had the same problem of landing them as they handle so differently to a flight simulator. So really pleased to see this thread, maybe now I'll get into spaceplanes!

[Wanderfound]

Something worth keeping in mind for career mode, BTW: if you do end up missing the runway, you can taxi back onto it before recovery for 100% funds.

[Jovus]

EdFred, thank you, that was extremely helpful.

By the way, in case you all are curious, have a picture:

I've found that, very roughly, a good rule of thumb is: if you're below 1000m, your velocity needs to be below 200m/s (preferably below 175m/s) - if not, wave off, you're doing it wrong. Complementarily, if you're above 3000m, your velocity needs to be above 250m/s.

Of course this all varies with airframe. Oh, and fine controls are necessary unless you want to just return the cockpit.

ETA: I forgot to add, because I just figured this out: the position of your velocity vector below the horizon is important. When you're making final approach for landing, it should be ~2-4 degrees below - not more, not much less (again depending on approach path - if you're going to the middle or end of the runway, a velocity vector pointing too shallow will cause you to miss, but one pointing too steep will always cause you to crash.

That's velocity vector, not nose indicator. The latter's also obviously important, but the velocity vector is what determines whether you're going to belly-flop or miss or actually make a sensible landing. (This is the bit I think I was missing most - it should be obvious, and it is in retrospect.)

Edited August 21, 2014 by Jovus

[Wanderfound]

EdFred, thank you, that was extremely helpful.

By the way, in case you all are curious, have a picture:

http://i.imgur.com/20Xoyny.png

I've found that, very roughly, a good rule of thumb is: if you're below 1000m, your velocity needs to be below 200m/s (preferably below 175m/s) - if not, wave off, you're doing it wrong. Complementarily, if you're above 3000m, your velocity needs to be above 250m/s.

Of course this all varies with airframe. Oh, and fine controls are necessary unless you want to just return the cockpit.

I usually try to get down to ~100m and ~150m/s while I'm still a couple of kilometres short of the strip. Can't stand the fine controls, either; with normal controls, a tap is a tap is a tap, but with the fine controls you have to hold the buttons down and it goes "nothing, nothing, tiny bit, lots!".

Each to their own, though; there is no one true way.

--

Edited to add: hey, I recognise that plane...

Tried having a go at the speed challenge yet?

Edited August 21, 2014 by Wanderfound

[Jovus]

Interesting. Without fine controls on descent I pretty reliably rip the wings off due to trying to make tiny adjustments (while going, say, Mach 0.98 @ 1100 meters) and way overdoing it.

My 'advice' above (which was really just reporting) wasn't to do with distance from the strip, but distance on the altimeter, though they are loosely related.

[EdFred]

Not necessarily; I usually try to get down to ~100m and ~150m/s while I'm still a couple of kilometres short of the strip. Can't stand the fine controls, either; with normal controls, a tap is a tap is a tap, but with the fine controls you have to hold the buttons down and it goes "nothing, nothing, tiny bit, lots!".

Each to their own, though; there is no one true way.

--

Edited to add: hey, I recognise that plane...

Tried having a go at the speed challenge yet?

Completely depends on design though. You don't land a 747 at the same speed as a Cessna 172. Same with KSP. I've designed planes that fly as slow as 20m/s, and others that won't fly unless they are over 100m/s.

[Alshain]

Jovus, I can't help but notice you said your using FAR, but nobody here has mentioned spoilers and flaps so I'm going to.

Spoilers can be set on control surfaces in the SPH using tweakable menus and then triggered by action groups. Their primary purpose is reducing speed. When triggered the control surface will raise severely and *I think* their ability to control rotation and pitch is reduced. When deactivated they still act as normal control surfaces that can control roll and pitch (and technically yaw but they shouldn't).

Flaps are used to add stability when the plane is at low speeds. When configured for flaps, control surfaces will not control pitch, rotation, or yaw, even if they are set to true. Flaps are controlled by two action groups, one to deflect more (at lower speeds), and one to deflect less (higher speeds). There are 4 positions for the flaps in total from fully deployed to fully retracted.

Make sure your plane is properly configured. On the plane you have above, the front canards should have yaw and rotation turned off. The rear control surfaces should have yaw turned off, and tail fin should be yaw only (though my personal preference is to have no yaw control at all on my planes, I use non-moving tail fins).

On your design above I don't recommend flaps because you only have 2 groups of control surfaces that I can see. You can use the rear control surfaces as spoilers though.

Other speed control options:

Air breaks: the B9 pack has theses, they are good for beginners but almost feels like cheating to me now.

Drag Chutes: For bigger planes landing on small runways (like the island) drag chutes are essential. For beginners they can help as a last minute speed drop for smaller planes. Get familiar with the RealChutes addon, which is configured from the Action Groups tab by clicking a parachute. Make sure you set it to be a drag cute and not a main chute, which is default. Then arm it with an action group after you take off.

Below is a very simple plane I built for practicing landings. It has a very stable high dihedral wing with 3 control surface groups. (If you like I can give you the craft file later, this screenshot is an older version where the tail fin and pitch surfaces are backward). On this plane, the rear surfaces are pitch only, the inner wing are flaps, and the outer small surfaces are rotation/spoilers.

[Wanderfound]

Interesting. Without fine controls on descent I pretty reliably rip the wings off due to trying to make tiny adjustments (while going, say, Mach 0.98 @ 1100 meters) and way overdoing it.

My 'advice' above (which was really just reporting) wasn't to do with distance from the strip, but distance on the altimeter, though they are loosely related.

Yah; sorry. I edited my post when I realised that we weren't actually disagreeing.

The reason you're snapping the wings is the speed; Mach 0.98 is faster than any plane could manage until Chuck Yeager did his thing. It might feel slow, but it isn't.

I normally come in from orbit with engines off at ~Mach 7, keep it at 20,000m until I've slowed below Mach 2, then gradually drop down to about 2,000m to wash off the rest of the speed. I don't try any sort of manoeuvring until I'm thoroughly subsonic. And I never hold down the keys; it's always tap tap tap.

Then it's back up a bit to get over the mountains west of KSC, maybe turning the engines back on for a few seconds if I've left it too late and need to climb steeply, then drop down to below 1,000m (engines off again) as soon as I can. Once the speed is down to 150m/s I'll turn them back on with just enough throttle to maintain that speed until the runway is in sight, then it's throttle off again all the way to landing. I like to glide...

Edited August 21, 2014 by Wanderfound

[Wanderfound]

Spoilers are also activated by the B key, by the way. I use them mostly for downforce and braking after I've touched down.

[Hodo]

Simple answer is this.

Your landing speed is to high. 200m/s is still well over 400mph! I like to land around 70-120m/s depending on the craft. I try to keep my rate of decent around 5m/s to no more than 10m/s. If you are coming down faster than that you are going to slow or have to steep of a rate of decent. If you are coming in at a higher rate of speed then you need to burn some speed off either with airbrakes or spoilers.

I generally line up 10km out and begin a gentle glide slope from there.

[Alshain]

Spoilers are also activated by the B key, by the way. I use them mostly for downforce and braking after I've touched down.

Yes, that is true by default they are. I take them off that though and use my own action group because I use them to slow down on approach and I don't want the wheel brakes on when I touch down.

[Geschosskopf]

Spoilers can be set on control surfaces in the SPH using tweakable menus and then triggered by action groups. Their primary purpose is reducing speed. When triggered the control surface will raise severely and *I think* their ability to control rotation and pitch is reduced. When deactivated they still act as normal control surfaces that can control roll and pitch (and technically yaw but they shouldn't).

Actually, the spoilers just reduce lift. If they have any effect on speed, it's minimal (I've never noticed anyway). Their purpose is to make you lose altitude quickly without you gaining speed by having to dive. IOW, they steeping your glide path. This is useful if you're trying to land in a small field with tall hills nearby on the approach side, of if you've got a STOL plane that just doesn't want to quit flying and you want to land NOW instead of circling around for the next 10 minutes.

Think of spoilers as a staircase. You're in your normal relatively flat glide regime and see you're too high. So you pop the spoilers and you basically go straight down while the plane remains essentially in the same attitude it was before, without increasing speed. When you get low enough, you retract the spoilers and resume your normal, relatively flat glide slope which you had before. So it's like you took a step down.

Spoilers will also help spaceplanes come down for good during reentry, instead of skipping and gliding 1/2way around the planet before you can land them. However, because they steepen your descent, they increase reentry temperatures if you're using DRE so be careful.

In general, spoilers are of limited use, mostly at an early stage of the approach. Do NOT leave them on during final approach because they increase your vertical speed, making it more likely you'll crash.

It's best to have dedicated control surfaces as spoilers. Attach them so they lie flat on the upper wing surface and use them via an action group only as needed. When you trigger the action group, they'll pop up at whatever angle you've set for them. I recommend at least 25^, usually more like 40^. Be sure the action group is to toggle so you can open and close them with 1 key.

Flaps are used to add stability when the plane is at low speeds.

Flaps are the opposite of spoilers. They increase lift, so make the glide path flatter, and allow planes to remain flying at lower speeds, than their wings alone would allow. High speed planes typically don't have much wing because lift is a function of speed so they get all they need by going fast, and having more wing would created drag and not let them go as fast. But they still have to fly slow at takeoff and landing, so they use flaps to fool the air into thinking they have big wings when flying slow.

Air breaks: the B9 pack has theses, they are good for beginners but almost feels like cheating to me now.

Firespitter has them also.

Airbrakes ain't cheating, no more than flaps and spoilers. They're just another control surface. Airbrakes increase drag so decrease forward speed. This is good for killing off high speed in a hurry to drop into your normal glide path speed. Once you're down to the desired speed, be sure to close them again. And be careful using them because if you're not paying attention and leave them on too long, they will of course stall you. Also, airbrakes are another good way to keep reentering spaceplanes from hopping all the way around a planet, and are better at this than spoilers because they don't steepen the reentry trajectory as much.

Drag Chutes: For bigger planes landing on small runways (like the island) drag chutes are essential. For beginners they can help as a last minute speed drop for smaller planes. Get familiar with the RealChutes addon, which is configured from the Action Groups tab by clicking a parachute. Make sure you set it to be a drag cute and not a main chute, which is default. Then arm it with an action group after you take off.

Drag chutes ain't for beginners as they're highest and best use IMHO is for planes intended to land on other planets where there ain't runways. Nothing sucks more than getting a plane all the way to Laythe, make a perfect reentry and landing approach, set down for a nice, smooth landing, and then crash due to bouncing on uneven ground, when the plane's bouncing too much to use the brakes because not all wheels are on the ground at once. Drag chutes solve that problem admirably.

With drag chutes, you can set them trigger on ground contact but I agree with Alshain that action groups are better. This is because when not flying from a runway, you'll usually bounce a few times during your takeoff run and if the chute is set for auto ground contact deployment, it will fire during your takeoff and kill you. And also be sure that you provide a way for a Kerbal to get close enough to repack the chute if you plan on using it more than once.

Edited August 21, 2014 by Geschosskopf

[Jovus]

One other thing I've noticed is that while spoilers are supposed to decrease lift, depending on your speed and their strength (i.e. their size and deflection angle) they can incidentally increase your angle of attack, which increases your lift...

[Alshain]

Actually, the spoilers just reduce lift. If they have any effect on speed, it's minimal (I've never noticed anyway). Their purpose is to make you lose altitude quickly without you gaining speed by having to dive. IOW, they steeping your glide path. This is useful if you're trying to land in a small field with tall hills nearby on the approach side, of if you've got a STOL plane that just doesn't want to quit flying and you want to land NOW instead of circling around for the next 10 minutes.

Well that's kinda what I said, but I may not have explained it clearly. They reduce your speed as you descend, where as normally descending would increase your speed.

Airbrakes ain't cheating, no more than flaps and spoilers. They're just another control surface. Airbrakes increase drag so decrease forward speed. This is good for killing off high speed in a hurry to drop into your normal glide path speed. Once you're down to the desired speed, be sure to close them again. And be careful using them because if you're not paying attention and leave them on too long, they will of course stall you. Also, airbrakes are another good way to keep reentering spaceplanes from hopping all the way around a planet, and are better at this than spoilers because they don't steepen the reentry trajectory as much.

Again, lack of explanation on my part. Airbrakes themselves aren't cheating, the B9 ones feel like it because for their size they are massively overpowered.

Drag chutes ain't for beginners as they're highest and best use IMHO is for planes intended to land on other planets where there ain't runways. Nothing sucks more than getting a plane all the way to Laythe, make a perfect reentry and landing approach, set down for a nice, smooth landing, and then crash due to bouncing on uneven ground, when the plane's bouncing too much to use the brakes because not all wheels are on the ground at once. Drag chutes solve that problem admirably.

And again, specifically for beginners with small planes. The plane I posted above shouldn't need drag chutes, but for a beginner learning to land I found them useful and later removed them as I became more practiced at controlling by speed through throttle, spoilers, and S curves. Absolutely useful for large heavy planes that would otherwise have trouble slowing down on their own, especially coming in from orbit.

Edited August 21, 2014 by Alshain