Weekly Challenge #53: Build a Seaplane!

[Dakota]

Build a plane that's also a boat! It must be able to take off from and land safely on water.

Primary: Launch an aircraft from the water and land it on the water.
Secondary: Build an amphibious seaplane that can also land on a runway.
Jeb: Land a seaplane on Laythe's ocean that is able to take off again to explore the planet.
Val: Build a seaplane that is also an SSTO vehicle.

[Goddchen]

Here is my take on it. I really struggled to build something that actually floats. How do you normally do that? Does the physics engine event allow/support this?

 

[Flush Foot]

33 minutes ago, Goddchen said:

I really struggled to build something that actually floats. How do you normally do that? Does the physics engine event allow/support this?

That's what I was wondering last night too...

I occasionally managed to get (and stay) airborne from a water-launch but had (slightly) more success lifting off from the runway and then gliding down to the water just beyond the runway to see if I could survive a water landing.

/summon BuoyancyMasters

[Meecrob]

1 hour ago, Goddchen said:

Here is my take on it. I really struggled to build something that actually floats. How do you normally do that? Does the physics engine event allow/support this?

IIRC use empty fuel tanks.

[Goddchen]

3 minutes ago, Meecrob said:

IIRC use empty fuel tanks.

That totally did not work for me at all

[Flush Foot]

1 minute ago, Goddchen said:

That totally did not work for me at all

Likewise... I went from 1.25m empties up to even 2.5m empties as 'pontoons' and it barely had my cockpit out of the water. :-\

[Goddchen]

I came up with a cool technique that I named "dippedidip launch", check out the video

[Meecrob]

Lol, ok now I'm gonna have to try it myself. Sorry, I didn't mean to mislead, I was just remembering how it was done in KSP1

 

Ok, so it sorta works, but I keep running into the bug in the VAB when you revert, it puts half your stuff that is in symmetry in the floor, so I give up. I'm still working on last weeks challenge anyways. Good luck!
 

Edited April 23 by Meecrob

[mattihase]

Funnily enough I was working on something like this over the weekend. Only really hits the first objective and it's not very practical but I had a lot of fun working on it so I may come up with something specific for the challenge later this week.

 

Aside from the tanks/tank intake on the engine block, most of that is empty tank. So... yeah, if you want bouyancy you really do need a hell of a lot of empty tanks.

[mattihase]

I wouldn't be surprised if Goddchen's dippedidip launch methods ends up being the most practical way to get anything with the right shape and fuel distro to cut it as an SSTO out of the water.

[astrobond]

11 hours ago, mattihase said:

Funnily enough I was working on something like this over the weekend. Only really hits the first objective and it's not very practical but I had a lot of fun working on it so I may come up with something specific for the challenge later this week.

 

Aside from the tanks/tank intake on the engine block, most of that is empty tank. So... yeah, if you want bouyancy you really do need a hell of a lot of empty tanks.

OMG Porco Rosso Plane ? Excellent xD

[ralanboyle]

Alrighty, after fighting several glitches I got my Float SSTO working. Now that Val is out of the way I'll try something a little more traditional. 

 

Edited April 25 by ralanboyle
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[Goddchen]

5 hours ago, ralanboyle said:

Alrighty, after fighting several glitches I got my Float SSTO working. Now that Val is out of the way I'll try something a little more traditional. 

 

Wow! Dippedidip launch it is  And very impressive how it can generate that much lift with less than 40 m/s! Is it because of the 4 wings?

[mattihase]

6 hours ago, ralanboyle said:

my Float SSTO 

Kinda reminds me of a hypothetical midpoint of sea dragon and the space shuttle. Very cool idea.

[ralanboyle]

4 hours ago, Goddchen said:

Wow! Dippedidip launch it is  And very impressive how it can generate that much lift with less than 40 m/s! Is it because of the 4 wings?

Yep, stall speed is directly connected to wing loading. So if you want to be able to fly slower, increase your wing area relative to total weight. 

[ralanboyle]

Here is my more conventional Sea Plane, I imagine it being what Icon Aircraft would make if they made a twin jet. It is not useful but its fun and easy to fly. 

@Goddchen A note on what you are calling Dippedidip. This move you are doing is giving your wing a positive angle of attack. When you take off from a runway, your elevator causes the tail to go down, which creates a positive angle of attack on your main wing. Since these planes are in the water, the tail cannot go down so you have to go underwater and then pitch up in order to get the tail down. In real life, sea planes use flaps to overcome this, but since flaps aren't available in KSP, you can just angle the whole wing up a little bit. I could nerd out for awhile talking about how various shapes create lift but I'll leave it at this for now. 

 

 

[Goddchen]

1 hour ago, ralanboyle said:

Here is my more conventional Sea Plane, I imagine it being what Icon Aircraft would make if they made a twin jet. It is not useful but its fun and easy to fly. 

@Goddchen A note on what you are calling Dippedidip. This move you are doing is giving your wing a positive angle of attack. When you take off from a runway, your elevator causes the tail to go down, which creates a positive angle of attack on your main wing. Since these planes are in the water, the tail cannot go down so you have to go underwater and then pitch up in order to get the tail down. In real life, sea planes use flaps to overcome this, but since flaps aren't available in KSP, you can just angle the whole wing up a little bit. I could nerd out for awhile talking about how various shapes create lift but I'll leave it at this for now. 

 

 

@ralanboyle Wow, congratulations. I have to say, I am really impressed and this gives me a lot of ideas that I have to try out this evening, thanks!

Edited April 25 by Goddchen

[mattihase]

Ah. You can also change your angle of attack by angling the wings during building, so that might be a good workaround.

[ralanboyle]

3 hours ago, mattihase said:

Ah. You can also change your angle of attack by angling the wings during building, so that might be a good workaround.

Yeah, that's what I was trying to say. You worded better...

[Meecrob]

4 hours ago, mattihase said:

Ah. You can also change your angle of attack by angling the wings during building, so that might be a good workaround.

*Cough cough* angle of incidence. As in the angle the fuselage meets the wing, vs angle of attack which is the angle the relative wind meets the wing. I know you meant the correct thing

[ralanboyle]

I decided I needed to go big, I ended up with something that I imagine as a military cargo float plane... It is fairly hard to fly due to adverse pitch while commanding roll, but she stalls super slow so spot landings are fun! 

 

[Goddchen]

Thanks again @ralanboyle and everyone else for the tips. I came up with an improved version of my sea plane:

 

[ralanboyle]

@Goddchen, looks good. Thanks for the shout out. 

[Urus28]

I explored Laythe with a seaplane

[Goddchen]

9 minutes ago, Urus28 said:

I explored Laythe with a seaplane

looks quite windy