How to land a plane?

[Pawelk198604]

When i play KSP i mostly do rockets, i for long time not design airplanes, but i decided to create one, Jeb died several times, but back to life thanks autosave and revering (like in Groundhog Day )

But finally i made working plane i watched some Tutorials online and i made it:D but have problem with landing when i tried to land speed is always 80-110, so i ejected capsule.

How to make landing smoothly?

http://1drv.ms/1w8HyFL

[Alshain]

80-110 m/s is a fine landing speed. You just have to keep your nose up so you don't bounce or worse. It really just takes practice, there is no other trick to it.

For your craft design, the wider the rear wheels are, the easier it will be. You can land on a bicycle but it's going to be harder. The problem I see here is the nose is very heavy and you don't have a lot of lift. Remove the forward fuel tanks on the outside. Get your center of mass somewhat to the rear of the plane to help you pitch up for landing.

Edited October 15, 2014 by Alshain

[Pawelk198604]

80-100 m/s is a fine landing speed. You just have to keep your nose up so you don't bounce or worse. It really just takes practice, there is no other trick to it.

I tried to land on water and grass, maybe this was problem?

I think i should invest in MJ2 :-)

Can you try my design?

PS does is possible to launch plane from opposite side of runway?

Edited October 15, 2014 by Pawelk198604

[Alshain]

I tried to land on water and grass, maybe this was problem?

I think i should invest in MJ2 :-)

Can you try my design?

I'm not at a playable computer right now, but after enough building, just looking at a plane tells me a lot and this one says heavy front end. You really don't need that much fuel or engine for a plane that size unless your plan is to circumnavigate the entire planet.

Edited October 15, 2014 by Alshain

[Wanderfound]

1) Listen to Alshain.

2) Wanderfound's reentry/landing guide:

* Send a Kerbal to the beach at the east end of the runway. Plant a flag. You now have a landing beacon. Set this flag as a target.

* Burn retrograde until your trajectory intersects the ground on the west side of the KSC home continent.

* As you descend, keep your nose within 10° of prograde and immediately correct any stall. You can afford a much larger AoA at higher altitudes, but you should still avoid stalls and close to prograde as soon as you start to feel the atmosphere through your controls.

* Pull up as sharply as you dare. Aim to level out at ~25,000m.

* Check your distance to KSC. If it's over 200km, slowly descend in order to hit 6,000m at the mountains west of KSC (which are about 5,000m tall). If it's within 200km, begin S-turns to wash off speed and altitude.

* S-turns. First, decide how urgent the turn is and whether you also want to drop altitude. If the turn is urgent or you want to drop, stand the plane on its wingtip, keep the nose on the horizon and pitch up (carefully). If less urgent or you want to maintain altitude, roll to ~45° and pitch/yaw the nose around, monitoring climb rate and controlling it with pitch as you go.

* Make sure the flag is still set as target. If your prograde and target markers coincide, you're heading for the end of the runway. If they aren't on a bearing of 90° while you're doing this, you're coming in at an angle. Fly to the side until the target indicator is at 90°. Then fly towards it.

* Get lined up, low and slow as soon as possible. As soon as you're over the mountains, start doing S-turns and drop to the deck. Pull it down to <150m/s and <500m altitude, then point at the runway and level your wings. The shallower the approach the better. Keep engines on minimal throttle to hold speed constant.

* Avoid any drastic manoeuvres over the runway. You'll probably overdo it and make things worse.

* Watch your VSI (vertical speed, to the right of the altitude meter) and keep it to 5m/s or so. Triggering spoilers will increase it; balance the spoilers will gentle pitch-up.

* Don't be afraid to wave off and go around again if it gets messy. Also remember that the paddock beside the runway is an easier landing strip than the runway itself.

* Be ready to hit the brakes and do some delicate steering as soon as you land. Stick to the middle of the runway if you're using it. Trigger RCS and Vernors and use the "N" key for retro thrust.

[Tw1]

I tried to land on water and grass, maybe this was problem?

I think i should invest in MJ2 :-)

Can you try my design?

PS does is possible to launch plane from opposite side of runway?

No, but this sounds like a great idea to add with the Kerbal constructs mod.

[Oafman]

Landing on water is extremely difficult, but grass is possible.

Try to unsure your vertical speed is low (ie you're not dropping too fast) as you get close to the ground. Then 'flare' the plane, by pulling up the nose; this will slow you down, and allow your rear landing gear to touch the ground first.

When this happens you'll slow down quickly, and your nose will drop forward so your forward landing gear also touches the ground. Then you can tap the brake key to bring yourself to a halt.

100m/s is fine for airspeed just before you land. Your flare maneuver will reduce that a little, then the friction between your wheels and the ground will quickly slow you down. Just practice this a few times, and it will become second nature.

[SkyRender]

Landing is, as mentioned, not that difficult as long as you keep your plane's nose up during the landing sequence. This can be tricky in stock at times, especially if your vehicle has too many lift surfaces, as there's a bug in stock KSP aerodynamics that causes lift to constantly generate force on a craft while in-atmosphere (usually referred to as the "infiniglide" bug since you can exploit it with enough control surfaces and fly with no engines at all by flapping them). It does help to land somewhere flat. Also, during the final sequence, don't just hold down the brakes; pulse them and stop if your craft starts to tilt. If your craft seems very prone to tilting, your landing gear probably needs a re-balance. The gear should be at least 50% of your total wingspan away from the center of your craft for any paired landing gear.

Also, there's a few tricks to designing a plane that aren't readily apparent from your typical tutorial, but that will affect your landings more than your take-offs. One of them is controlling your fuel flow so that the craft's center of balance remains the same throughout. If you just build your typical cockpit-fuel-engine model of plane, it will have a center of mass pushed either far forward or far back by the end of your flight depending on which end is heavier, causing your plane to naturally want to tilt up or down (which depends on the way it's been pushed). This makes landing difficult, to say the least. You probably won't run into it with a test flight, but you definitely will on a full-scale one that ends with your fuel levels meaningfully drained.

[soulsource]

I figured, that with stock KSP the biggest issue (for me) is vertical speed. So, what I usually do is to give some thrust while landing, what increases horizontal velocity, and with it lift, in order to keep the vertical velocity below 5 m/s. If that doesn't help, the only thing I could think of is to increase lift to mass ratio (in other words: bigger wings).

In the case you are using FAR, you can designate control surfaces to act as flaps in the SPH using the right click menu. Then you can increase flap inclination during flight using action groups (which of course have to be defined in SPH first) or the right click menu, giving a huge boost in lift. (Also, remember to set flap inclination to zero after takeoff.)

I don't know if that's of any help for you, but keptin wrote an excellent guide on airplane design.

[Pawelk198604]

I'm not at a playable computer right now, but after enough building, just looking at a plane tells me a lot and this one says heavy front end. You really don't need that much fuel or engine for a plane that size unless your plan is to circumnavigate the entire planet.

Truth be told, I decided to build this plane because I did not want to pay liquidated damages for not fulfilling the contract, accepted a contract to test the "basic jet engine," I had it activated at engine speed of 120-220, at a height of 10100 to 12000. I just not read conditions of contact

[Alshain]

No, but this sounds like a great idea to add with the Kerbal constructs mod.

Well, depends on what you call "launch". You can always taxi your plane to the other side of the runway.

Truth be told, I decided to build this plane because I did not want to pay liquidated damages for not fulfilling the contract, accepted a contract to test the "basic jet engine," I had it activated at engine speed of 120-220, at a height of 10100 to 12000. I just not read conditions of contact

Well that explains the engines, but another option would be to use the thin LFO tanks to mount the outer engines and drain the Oxidizer using tweakables. It may not be as pretty but it keeps the weight at the back and has more than enough fuel for jet engines. You can even action group the outer engines and only turn them on when your ready for speed as one jet engine is going to be more than enough to take off and land. Though really I would have thought one basic jet would get to 120m/s in stock.

Edited October 15, 2014 by Alshain

[Pawelk198604]

Well, depends on what you call "launch". You can always taxi your plane to the other side of the runway.

Yes i know that, but why i cannot chose from where i can take off. But i fulfilled my contractual obligations, i lost plane, but Jeb survived so i can consider this a success

[Pawelk198604]

Well, depends on what you call "launch". You can always taxi your plane to the other side of the runway.

Well that explains the engines, but another option would be to use the thin LFO tanks to mount the outer engines and drain the Oxidizer using tweakables. It may not be as pretty but it keeps the weight at the back and has more than enough fuel for jet engines. You can even action group the outer engines and only turn them on when your ready for speed.

I was need activate it trough staging sequence

[Alshain]

Yes i know that, but why i cannot chose from where i can take off. But i fulfilled my contractual obligations, i lost plane, but Jeb survived so i can consider this a success

I with you there. I'd love to be able to choose a launch position. For that matter I'd love a KSC with a North/South runway.

I was need activate it trough staging sequence

That would let you turn them on, Action Groups lets you turn them back off. A technique needed if you want to send anything other than rapiers to space. But even in this case, 3 engines would make it hard to slow down, even with throttle.

[Oafman]

I with you there. I'd love to be able to choose a launch position. For that matter I'd love a KSC with a North/South runway.

Just use the field. You also get a free bit of acceleration from the slope off the runway

[qromodynmc]

Landing is easy but,your plane lacks of control surfaces,so it may be bit harder. Anyway keep your attack of angle high,try to glide,and make sure you are losing altitude at minimum speed.

[SkyHook]

Increasing your wing surface will help you a lot. That small of a wing means very high landing speeds and more stress on the airframe upon landing. Also, keep your vertical speed to under 5 m/s upon landing if you like Jeb

[michaelhester07]

You can practice landing in a flight simulator. KSP's aerodynamics seem to be similar enough.

There's one based on google earth for free: Google Earth Flight Simulator.

To keep this about KSP though here's a basic landing sequence for a plane (not space plane just airplane) that I followed to land.

First: remember your takeoff speed. This will be where you need to be when you land. My plane's speed was 50m/s

Reduce your throttle and keep your nose level. You'll maintain airspeed by reducing altitude. Start descent about 20km out from the space center. About 3 Km out from the runway drop to 500 meters altitude. When you're over the shore or the grass (depends on landing direction) kill your engines and pitch up to reduce vertical speed. You'll lose horizontal speed. This is ok. At 80 meters altitude pitch up hard enough to reduce your speed to the takeoff speed and to reduce your vertical speed. Let your plane drift down till wheel contact. Once you're down tap the brakes to slow down. Don't slam on the brakes as you could flip your plane.

Edited October 15, 2014 by michaelhester07

[Scarecrow88]

I downloaded your craft and have the following observations after trying to fly it:

You have used a really small pair of wings. With all the fuel and engines you have, it's not the lightest of craft, and the small wings means the craft has a very high wing loading. What this means in simple terms is that to generate enough lift to stay airbourne, it has to be moving quite fast, which makes it tricky to land.

Another problem is that the control surfaces don't provide much authority, especially in pitch. This makes it difficult to keep the nose up when flaring for a landing.

I tried a quick redesign, by removing the two outer engines and associated fuel tanks. Like this, it flew a bit better, but still suffered from a lack of lift and poor control authority, which still made it tricky to land. I think you would have more success if you used a slightly bigger pair of delta wings, as this should give more lift at slower speeds. Currently it doesn't fly very well at low thrust settings, as it is very difficult to stop it losing height really quickly.

[luizopiloto]

60~70m/s is the speed for landing... pitch up to flare close to touchdown to reduce vertical speed... and land...

[Alshain]

60~70m/s is the speed for landing... pitch up to flare close to touchdown to reduce vertical speed... and land...

I've gotta ask why? Why 60-70m/s?

Did you know the NASA Space Shuttle landed at 214 to 226 MPH or 95 to 101 m/s?

I'm seriously asking why. I see that recommendation a lot and I don't understand it because I can land 150 m/s just fine. Any idea where that range comes from?

[problemecium]

Like this:

[Progressm]

I suggest downloading an easy beginner plane design by someone else first, there are plenty around.

Rather than practicing all the way to orbit, just take off, go around, line up, land. Repeat. As to landing speed... It's easier if you are going slow while remaining above stall speed, as you have more time to adjust, flare etc. Less energy involved as well. In stock KSP a simple plane has enough lift to behave well at 50m/s so that's the speed it is easiest to land.

The space shuttle had the gliding ratio of a pig with wings, hence it had to land at high speed to retain enough lift for a flare.

Sure you can land things at 300m/s in KSP if you like (and walk away intact) but that's not ideal or realistic, or the safest beginner method to learn on either.

[capi3101]

I'd suggest setting up a rudimentary ILS for the runway before you fly anything. Take a Kerbal, stick him in a rover and drive him to the ocean end of the runway. Get just off the raised bit (the ramp up to the runway itself) and plant a flag. Go to the other end of the runway; repeat. Go west one kilometer; repeat. If you've done it right you now have three markers in a relatively straight line right along the axis of the runway. If the flags don't work out for you, try a rover with drop probes, and reclass the probes as Bases when you release them; I've done that before and you can see them when you're flying over KSC in orbit. If you want to, you can add additional markers at five kilometer intervals further inland. Like this:

The markers do two things for you. First, they help you get lined up over the runway. Second, if you set your markers to tell you how far out they are from the runway, you can use them to help determine your glide slope. The altimeter reading you want is the distance to the marker plus the distance indicated by the marker times 100. For example -

In this image I'm 8.6 kilometers away from the five kilometer marker. Using the formula above, my altimeter reading should be (8.6 + 5.0)*100=1,360 meters. I'm at 1,460 in that screenie, so I'm about a hundred meters too high. (Actually, you don't want your altimeter to get all the way to zero - the elevation of the runway is around 70 meters above sea level - so in truth I'm close to being right along the correct glide slope in this picture).

In any case, you want your vertical speed to be low when you finally make contact with the ground - I'd say no faster than 5 m/s downward or so. Kill your engines just above the ground and flare your nose up to no more than about 5 degrees above the horizon. Hit the brakes as soon as you make contact with the ground.

Curiously enough, I was travelling about 70 m/s when I landed this thing...just the way it worked out that time.

Edited October 15, 2014 by capi3101

[Scarecrow88]

60~70m/s is the speed for landing... pitch up to flare close to touchdown to reduce vertical speed... and land...

Did you download that craft and try flying it? At 60 - 70 m/s it has all the flying qualities of a brick, with a flight path that is heading towards the ground as much as it is going forward, which doesn't make for the gentlest of touchdowns.