Help? I can't land my plane :(

[DracoSilverpath]

Hey! So I made this little plane thingy for starting off in my career mode playthrough, and it takes off well! Only problem now is...I can't seem to land it! I've tried must be 2 dozen times, and I always end up in a fireball on the ground and dead Kerbals everywhere...

Anyone mind taking a look at it and telling me if its my design, or am I just incompetent when it cums to flying?  Any tips would be appreciated!

https://kerbalx.com/DracoSilverpath/ASC-Oppurtunity-Ascension

Mods used: B9 Procedural Wings, FAR, Taerobee, Tweakscale

[James Kerman]

There are some problems with landing gear, wheels and landing legs at the moment.  Are you having problems on touchdown?

[TheWanderer05]

Maybe try landing without the airbrakes, use the thrust reversers on the the engines. Airbrakes seem to cause some forced pointing-in-undesired-direction, so I hope this helps.

[DracoSilverpath]

4 minutes ago, James Kerman said:

There are some problems with landing gear, wheels and landing legs at the moment.  Are you having problems on touchdown?

See, I'm not sure! It takes off perfectly fine, no issues, flies fine, rolls around on the ground fine, etc. Problem I found is that I end up bouncing like a trampoline when I go to touchdown, and it doens't help that this thing stalls out at around 100ms, so getting slow enough to land I've found really difficult, and is the sort of thing I could use advice on.

6 minutes ago, TheWanderer05 said:

Maybe try landing without the airbrakes, use the thrust reversers on the the engines. Airbrakes seem to cause some forced pointing-in-undesired-direction, so I hope this helps.

I've tried that, I stuck em on in a desperate attempt at even getting close to landing speed, and still not really being able to do so.

[James Kerman]

The bouncing around sounds like the wheel bug to me - particularly if you are flaring hard before landing.  As a test you could enlarge the main wings (increasing lift and drag) and see if that helps you land.  Be sure to check your center of mass and center of lift in the VAB first.

[DracoSilverpath]

16 minutes ago, James Kerman said:

The bouncing around sounds like the wheel bug to me - particularly if you are flaring hard before landing.  As a test you could enlarge the main wings (increasing lift and drag) and see if that helps you land.  Be sure to check your center of mass and center of lift in the VAB first.

Okay, I went and enlarged the wings by another 50%, made it extremely easy to takeoff and control altitude! Landing though....nope. I touched down at roughly 100ms or so, with very little vertical speed, and boing! bouncing like a po-go stick the second the wheels touch the ground.

I had previously stiffened the springs in them to keep the craft from wobbling on thw runway when physics kicked in, which helped with that, but would it perhaps interfere with landing? I wouldn't think so...

[James Kerman]

Stiffening the springs may be the culprit.  Another simple test would be to revert them to default and place the landing gear on your engine nacelles - a wider wheelbase may mitigate the take-off instability.

[DracoSilverpath]

14 minutes ago, James Kerman said:

Stiffening the springs may be the culprit.  Another simple test would be to revert them to default and place the landing gear on your engine nacelles - a wider wheelbase may mitigate the take-off instability.

Tried your idea, sadly no luck. Loosening the prings and moving the wheels helped a little with landing as the tail didn't immediately smack the ground and explode, but in the end, it still bounced and went kaboom.

[James Kerman]

ok so with some research I found this thread:

Is your landing gear clipped in any way?

[DracoSilverpath]

Nope, no clipping or fancy moving around done

[James Kerman]

Looking at your design more closely I see the landing gear is attached to the wings.  This may be causing the wings to flex on landing creating the bounce.  Try attaching the landing gear to the fuselage and see how that goes, mate.

[DracoSilverpath]

27 minutes ago, James Kerman said:

ok so with some research I found this thread:

Is your landing gear clipped in any way?

Nope, no clipping/blocking problems

2 minutes ago, James Kerman said:

Looking at your design more closely I see the landing gear is attached to the wings.  This may be causing the wings to flex on landing creating the bounce.  Try attaching the landing gear to the fuselage and see how that goes, mate.

If I was to do that, the wheelbase would be extremely narrow...how would you get around that? 

Edited August 26, 2016 by DracoSilverpath

[James Kerman]

Use a Cubic Octagonal Strut  to space them out but attach the strut to the fuselage - it will look ugly and cause more drag but this is just a test.

[DracoSilverpath]

9 minutes ago, James Kerman said:

Use a Cubic Octagonal Strut  to space them out but attach the strut to the fuselage - it will look ugly and cause more drag but this is just a test.

Alright, tried your suggestion, and no go sadly.

I attached the beam to the fuselage, and then the gear to it. I touched down at about 90ms with less than 1ms vertical speed, and landed on all 3 wheels at the same time incase that was the problem, nope, it looked like it was going to work for a split second as it touched down, and then, boing! the nose catapulted up into the air and did the usual crash and burn routine....

[James Kerman]

So I'm out of ideas, mate.  Maybe one of the space plane masters can help?

[DracoSilverpath]

Just now, James Kerman said:

So I'm out of ideas, mate.  Maybe one of the space plane masters can help?

I hope so! Now I just hope wanders by~

[Columbia]

Try placing your landing gears farther out. What speed are you landing at?

[DracoSilverpath]

3 minutes ago, Columbia said:

Try placing your landing gears farther out. What speed are you landing at?

I've tried placing the gear both inline on the fuselage, and far outwards onto the wings, and variations inbetween, no seeming difference in landing problem.

I'm barely tapping the ground at about 100ms or so. Vertical speed has been anywhere from 5ms down to less than 1ms, and still pounces up like something posessed  

I've tried both flaring up at last moment, to gliding in on all 3, same effect.

As a note, I even built another craft with same design, but 2 center hulls for the sheels side by side with engines on the back instead of wings, and sadly it has the same issues as this. So I think its reasonably safe to say gear placement position isn't the problem.

[TheDestroyer111]

Did you try attaching the wheels to the fuselage itself and using the offset gizmo to push them to the sides so that the wheelbase is not too narrow?

[DracoSilverpath]

Just now, TheDestroyer111 said:

Did you try attaching the wheels to the fuselage itself and using the offset gizmo to push them to the sides so that the wheelbase is not too narrow?

Yes, was one of the first things I tried.

[TheDestroyer111]

11 minutes ago, DracoSilverpath said:

Yes, was one of the first things I tried.

If nothing helps you, you still have the last-ditch landing techniques which are either using parachutes (back in KSP 0.25 most peoples planes landed on parachutes ), or the probably more effective one which is using structural parts like girders, I-beams or structural panels. Although you have to land slower than 80 m/s to not explode, structural parts are definitely not as bounce-friendly as wheels. For takeoff you can either use wheels which you later retract to land on structural parts, or, if you have enough TWR or if you can attach rockets to the plane, you can takeoff vertically.

And another very effective landing technique is just landing on water. My current career mode workhorse spaceplane does exactly this  As long as your vertical speed on landing isn't too high, you won't destroy yourself like back in 0.25 (in these old times, water landing was dangerous, but you are playing on a newer version so it's rather safe)

Example plane landing on skids/structural parts: 

Edited August 26, 2016 by TheDestroyer111

[DracoSilverpath]

5 minutes ago, TheDestroyer111 said:

If nothing helps you, you still have the last-ditch landing techniques which are either using parachutes (back in KSP 0.25 most peoples planes landed on parachutes ), or the probably more effective one which is using structural parts like girders, I-beams or structural panels. Although you have to land slower than 80 m/s to not explode, structural parts are definitely not as bounce-friendly as wheels. For takeoff you can either use wheels which you later retract to land on structural parts, or, if you have enough TWR or if you can attach rockets to the plane, you can takeoff vertically.

And another very effective landing technique is just landing on water. My current career mode workhorse spaceplane does exactly this  As long as your vertical speed on landing isn't too high, you won't destroy yourself like back in 0.25 (in these old times, water landing was dangerous, but you are playing on a newer version so it's rather safe)

Good points, thanks for the info  the girders, while feasible, I don't think will work for me, due to the craft simply stalling out at around 100ms, and I'd need to be going much slower for it to work.

Water is a definite idea, though to be honest, I have yet to ever make anything that floats properly that isn't a straight up boat  do you have any smaller/intermediate craft you could show me for this idea?

[TheDestroyer111]

8 minutes ago, DracoSilverpath said:

Good points, thanks for the info  the girders, while feasible, I don't think will work for me, due to the craft simply stalling out at around 100ms, and I'd need to be going much slower for it to work.

Water is a definite idea, though to be honest, I have yet to ever make anything that floats properly that isn't a straight up boat  do you have any smaller/intermediate craft you could show me for this idea?

Add bigger wings to make it stall at slower speeds. BTW how much does this thing weight? It's a little impossible for it to stall at 100m/s, it should stall much slower...

For things that float, almost anything floats in KSP. One guy said that today, every spaceplane in KSP is also a very very fast boat.

Edited August 26, 2016 by TheDestroyer111

[DracoSilverpath]

6 minutes ago, TheDestroyer111 said:

Add bigger wings to make it stall at slower speeds. BTW how much does this thing weight? It's a little impossible for it to stall at 100m/s, it should stall much slower...

For things that float, almost anything floats in KSP. One guy said that today, every spaceplane in KSP is also a very very fast boat.

It weighs I think around...8-10 tons, alot of the weight is coming from the larger wings already, so making them even bigger and heavier I think would be counter-productive in this case?

And yes, that's true about the boat thing, but what about engines? Can't run a jet engine underwater for example  and every time I've tried to make  one, even if the engine was above, ti just -refused- to even move an inch in the water

[Fellow314]

Landing has become very tricky lately.

 

I have discovered that you need to land at just, and I mean only just, over stall speed, this will allow you to pull up madly when the wheels hit the ground and prevent (to a certain degree) the epic bouncing that seems to happen.  (If you try this while going too fast, you'll jsut take off again, of course.)