How to land airplane? Keep landing on water

[Reusables]

Hello, I'm new to the KSP, tried to land my first airplane on the runway. But I keep failing on deacceleration before landing, thus landing on the water.

Though I could land on water without any loss, I want my plane to land on the runway, since I've heard that it gives more money back on the recovery.

How should I deaccelerate my plane? Thanks!

[Empress Neptune]

The biggest factor in landing difficulty is probably how slowly your plane can safely fly. What is your speed just as you cross over the runway? Adding more lifting surfaces will help you fly more slowly.

Once you're on the ground, you want to make sure that your landing gear has proper traction settings. I turn off the automatic traction control and set the sliders to about 1 or 2. The rear wheels should have a  higher setting than the front. Increasing the traction setting will allow the brakes to work better. You can then improve the braking even more by having your control surfaces produce downforce instead of lift. Not only does this increase brake effectiveness, but it creates drag to help slow you down. I tend to use deployed control surfaces instead of dedicated airbrakes when I can to save some weight. Just make sure that your plane doesn't flip over when doing this. Flipping can be a problem for very light aircraft with large control surfaces.

[LN400]

Adding to the post above by Empress Neptune.

For each design, just like in real life, learn how the plane behaves at different speeds. Find the lowest speed where you can maintain control and not lose altitude. Remember that speed. Typically that will be near your minimum take off speed so remember which speed you took off at.

Before take off, memorize the pitch angle of the nose (look at the nav ball). That is the angle where you will land on all wheels. A couple of degrees up from that is where the drag helps you slow down while letting you land on the main wheels.

In flight, play with speed, controllability and descent. Find the speed where you can control the airplane while slowly losing altitude. That will be (near) your landing speed during finals.

A plane needs time to adjust so plan well ahead.

Like in real life, make a plan for the phases before touchdown, especially the finals which is the stretch you START losing altitude for landing. This needs to be started straight out from the runway, Don't do sharp turns during finals. It also needs a considerable distance. 5km out is not unheard of. Might very well be more.

Standardise your initial altitude and speed for finals. Start the finals at the same altitude each time, at the same speed. This makes it easier to find what needs to be corrected in future flights.

Allow a shallow descent. A straight sloped line is perfect at an angle of only a few degrees. You might have to wing it but if you pay attention to your speed and your descent rate then it can give you the ballpark figure you need.

Just above the treshold, just a few meters off the ground, cut the throttle and let the plane settle down (unless you are flying a grand piano tied to an anvil in which case you might need the throttle).

Keep practicing all the above and in particular the finals. Keep it standard.

Edited August 22, 2016 by LN400

[GraviTykillz]

Love to build SSTO in KSP and Have done lots of speed Flying..along with the good advice from those above me. you can also throw  a parachute on the back and use it on runway to slow down

Edited August 22, 2016 by GraviTykillz

[luizopiloto]

You basically reduce throttle so the craft speed remains between 80~120m/s, depends of size and lift capabilities.
Glide slope (trajectory angle relative to ground) indicated by the velocity vector, or the yellow prograde mark on the navball, if gliding down, must not exeed 30° when you align with the runway to land or the craft will not get slow enought... once you get above runway, pitch up until the Vertical Speed indicator gets to -5 to -3 m/s, and once the wheels get to like 1m to touchdown, pitch up a little more to land as smooth as possible...
then you click on the brakes icon to lock the brakes...

this video can help:
https://youtu.be/G7UcV0RUtqw?t=1011

 

[Talos]

Make sure the plane you've designed has good control surfaces, your wheels are properly configured and you have the ability to slow down quickly (if your craft is supersonic).

As for landing, you want to cut engines as you approach the runway and deploy flaps/airbrakes to slow yourself down to around 120 m/s. Lower yourself and continue to slow yourself down until you're over the runway, at which you then want to level out and allow your plane to lower itself down as it drops air speed. You should be at 75 to 60 m/s shortly before your wheels touch the ground. Now just allow your brakes to do the rest. If your plane is heavier and takes longer to slow down while going down the runway, you can use parachutes as soon as you touchdown to provide an additional source of drag to bring your plane to a halt.

[ForScience6686]

27 minutes ago, GraviTykillz said:

Love to build SSTO in KSP and Have done lots of speed Flying..along with the good advice from those above me. you can also throw  a parachute on the back and use it on runway to slow down

Another benefit of the rear mounted chutes is they help keep you pointed the right.  But use the drogue chute as it will stay with you until you stop fully.

 

Beyond that, real planes don't just dive down to the runway.  Generally they have a positive aoa on the descent.  Which will usually mean a powered landing to keep your speed above the stall limit until you reach the runway.  Another critical item is flaps.  These induce drag while providing more lift for better low speed flight.  I love them plus they look cool.  On my most recent space plane, I used what I'm guessing would be considered a spoiler.  This design has the wings at rear, the outer control surface is for elevator and roll, but is deployed in reentry causing the nose to pitch up.  The result causes the remaining elevators to try and push the nose back down increasing drag without any added parts, and it helps keep a positive aoa on descent.  

 

Beyond that you have air brakes, or reverse thrust options.

[Reusables]

Thanks for all the helpful tips!

EDIT: One more question, why is my plane getting its head up while the aerodynamic center is behind the gravitational center?

Edited August 23, 2016 by Reusables

[ForScience6686]

Your center of lift changes based on control surfaces and aoa.  So the tools you see in the sph only apply to horizontal level flight.  If you tilt control surfaces or the entire craft you will see how that affects col.   

[foamyesque]

18 hours ago, Abastro said:

Thanks for all the helpful tips!

EDIT: One more question, why is my plane getting its head up while the aerodynamic center is behind the gravitational center?

Possible explanations:

 

1. You're telling it to do so with a pitch-up command;

2. You have angled control surfaces that inherently cause a pitch up moment;

3. Your thrust axis is not aligned with your center of mass;

4. You've burned fuel, moving your center of mass behind your aerodynamic center;

5. Flap deployment giving you a pitch-up.

[Reusables]

7 hours ago, foamyesque said:

Possible explanations:

 

1. You're telling it to do so with a pitch-up command;

2. You have angled control surfaces that inherently cause a pitch up moment;

3. Your thrust axis is not aligned with your center of mass;

4. You've burned fuel, moving your center of mass behind your aerodynamic center;

5. Flap deployment giving you a pitch-up.

Thanks! I should check them.