Hi!

[jounce]

Hi!I'm a noob.I have learnt the way to make W-N(whiplash nerva) sstas that can carry payload less than a CRG-100(i can't carry a crg-100 payload and the required fuel tanks and the mining rig and the nervas with nervas that easily!)

How do I do that?

Right now,my spaceplane has a TWR of ~0.4 on both modes.But it cannot go to space because the drag is so heavy that it cannot get pass the sound barrier(at this point its twr is 0.41)The wing inclination is 5 degrees.

[jounce]

(btw nice mods!approved my post instantly )

[jounce]

Oops!Sorry!This post should be in the questions tag instead of the newbie tag?How can I fix it?

[James Kerman]

4 minutes ago, jounce said:

Oops!Sorry!This post should be in the questions tag instead of the newbie tag?How can I fix it?

Welcome to the forum @jounce! Your question has been moved from Welcome Aboard to KSP 1 Gameplay Questions.

[jimmymcgoochie]

SSTOs are hard; SSTOs that go somewhere beyond Kerbin orbit are hard²; SSTOs that carry mining equipment with them to go somewhere after they’ve gone somewhere beyond Kerbin orbit are hard³.

From your description it sounds like you have too much drag and/or not enough thrust. Can you share some images of the vessel in question? Try flying with the aero overlay on (F12) and see if there are any really large red spikes trailing from specific parts which indicate that they’re producing huge amounts of drag, then turn on the drag debug (alt+F12 > aero I think)  to confirm exactly how much drag is being produced and then tweak the affected part(s) to try and reduce it.

[jounce]

6 hours ago, jimmymcgoochie said:

SSTOs are hard; SSTOs that go somewhere beyond Kerbin orbit are hard²; SSTOs that carry mining equipment with them to go somewhere after they’ve gone somewhere beyond Kerbin orbit are hard³.

What?

Me:SSTOs are easy; SSTOs that go somewhere beyond Kerbin orbit are easy; SSTOs that carry mining equipment with them to go somewhere after they’ve gone somewhere beyond Kerbin orbit are easy.SSTOs that do not use closed cycle modes are hard³

 

6 hours ago, jimmymcgoochie said:

Try flying with the aero overlay on (F12)

I did,and the three main fuselages were making huge red spikes.That's how I got the conclusion of

8 hours ago, jounce said:

because the drag is so heavy

otherwise I only have evidence of the twr being too low(but some people have managed to go to orbit at twr 0.006!)

 

[jounce]

13 hours ago, jounce said:

Me:SSTOs are easy; SSTOs that go somewhere beyond Kerbin orbit are easy; SSTOs that carry mining equipment with them to go somewhere after they’ve gone somewhere beyond Kerbin orbit are easy.SSTOs that do not use closed cycle modes are hard³

Edit:

SSTOs are easy; SSTOs that go somewhere beyond Kerbin orbit are easy; SSTOs that carry mining equipment with them to go somewhere after they’ve gone somewhere beyond Kerbin orbit are easy.SSTOs that do not use closed cycle modes are hard;SSTOs that are slim(therefore not much engine attachment space) and use no closed cycle mode are hard³

[jounce]

Quitted not using closed cycle stuff.(used rapiers+nervs)

In orbit 83x84 LF 4809 OX 103(just for rcs,we have nervas to use in space) N(erva)DV 2268(enough for minmus and back,and we could just refuel at minmus)

(ima sleep,don't expect an instant reply)

Is experiencing stability issues(Controllable,but not much.If it is transonic or supersonic and in the atmosphere,then <s>Poland is on the right side</s> a slight wobble(even shift+w) in pitch will make it pitch uncontrollably up or down and disintegrate from aero forces.(has installed rcs build aid,has checked centers)

[king of nowhere]

19 hours ago, jounce said:

What?

Me:SSTOs are easy; SSTOs that go somewhere beyond Kerbin orbit are easy; SSTOs that carry mining equipment with them to go somewhere after they’ve gone somewhere beyond Kerbin orbit are easy.SSTOs that do not use closed cycle modes are hard³

 

I did,and the three main fuselages were making huge red spikes.That's how I got the conclusion of

otherwise I only have evidence of the twr being too low(but some people have managed to go to orbit at twr 0.006!)

 

as a rule of thumb, when you ask for advice you should post pictures. else people will have a much harder time troubleshooting.

especially in a case like this. sure, people could share with you projects of ssto that work. but to see the problem with your specific ssto and give advice for it, we need pictures.

[jounce]

https://kerbalx.com/jounce/ssta-special-cargo-load the new ssta im working on

https://kerbalx.com/jounce/sstaa-0 the old one that doesnt work(takeoff:yes,flying:yes,acceleration:yes,going supersonic:no)

 

Flight profile for both:Level flight(you will get a negative aoa due to wing inclination untill 500m/s(somehow manage to do so)then climb at 10 degrees untill IA gets used up,then climb as aggressive as you can,but not as aggressive that drag would rip the plane or slow it down, untill apoapsis going to space

Edited April 20, 2023 by jounce

[Vanamonde]

Might I suggest that pictures of the craft crashing is not putting your best food forward when attempting to attract customers?

[jounce]

 

2 hours ago, Vanamonde said:

Might I suggest that pictures of the craft crashing is not putting your best food forward when attempting to attract customers?

Woops!That was the default icon.Not my plane.Idk how to make photos of my plane.

[Vanamonde]

The screenshot is F1. Then you could upload your pics. 

[jounce]

Okay(how can i reduce fuselage drag from the non-working plane?)

[s_gamer101]

14 hours ago, jounce said:

how can i reduce fuselage drag from the non-working plane?

Well, you can't just magically reduce the drag of the fuselage (without cheating). You'd have to remove parts from it to reduce it's drag. But I need screenshots, otherwise I can't help you. (you can upload screenshots to imgur.com and then add them to your forum post)

[jounce]

i have uploaded the craft,just see it for yourself

[fulgur]

Here are some screenshots of Jounce's craft which I downloaded from KerbalX.

Jounce's first craft, which he says does not fly.

Jounce's second craft.

Your CoM and CoL are very close together. This makes your craft very manoeuvrable BUT it also makes it likely to flip over. If you put some more "Big-S Elevons" at the back of your wings it would make it a slightly more stable craft, or you could remove the canards or add more mass to the front.

You have a very large amount of wing area there. You do not need all those wings.

Even with autostrut, having a long series of radially attached fuel tanks is probably going to be unstable.

Notice the big drag vectors from all your surface mounted stuff. Put it in a service bay or three.

[s_gamer101]

Here are some things I notice on the screenshot of the second craft:

• Why is your fairing so long and yet so little inside of it? Is this supposed to be space for payload?
• If you have a fairing anyways and you want to reduce drag, why not put some batteries inside into the fairing instead of using those big batteries?
• And the excessive number of wings - why? Wings have a lot of drag. You should have just enough wings to have sufficient lift and not much more.
• Maybe just put all the mining stuff in a Mk 3 cargo bay
• What are those parachutes for? It's a plane after all...
• Is that a tricoupler with 3 engines at the back? There's absolutely no reason to not use a quadcoupler with 4 engines and have less radial engines instead
• If you're already using a command seat to save weight, it seems contradictory that you added a big, heavy, unmanned control unit when you could have just as well attached a lighter one.
• The same applies for the ore tank: The purpose of this plane isn't to carry large amounts of ore around. You do require an ore tank for the mining stuff, but the smallest variant of it will do the job
• Are you sure you need this many RCS trusters?

Also some advice for designing spaceplanes:

Don't put all the fuel and engines at the back. Because when you burn all the fuel, the center of mass moves very far with such designs, which also makes the behaviour of the plane change a lot during the mission and generally makes the desinging harder.

And here are some pro tips about the aerodynamic model of KSP:

• Construction nodes that aren't in a cargobay or fairing and don't have anything attached to them cause drag
  • When they are facing forward into the flight direction, they cause the most drag
  • When they are facing backwards, they cause the least drag
• Therefore the drag of a RAPIER-engine can be reduced by attaching a small 0.5-Meter-nosecone on the construction node at the back of the engine (and it also looks cool). It makes only a small difference, but it is a difference

[jounce]

2 hours ago, fulgur said:

Your CoM and CoL are very close together. This makes your craft very manoeuvrable BUT it also makes it likely to flip over. If you put some more "Big-S Elevons" at the back of your wings it would make it a slightly more stable craft, or you could remove the canards or add more mass to the front.

You have a very large amount of wing area there. You do not need all those wings.

Even with autostrut, having a long series of radially attached fuel tanks is probably going to be unstable.

Notice the big drag vectors from all your surface mounted stuff. Put it in a service bay or three.

1.Oh.Okay,But that doesn't fix Poland getting to the left side!(i.e vicious cycles)

2.Yeah.Agree.But they didn't produce THAT much drag,right?

3.They didn't get floppy on my test

4.Oops!Probably forgot that.

 

1 hour ago, s_gamer101 said:

Here are some things I notice on the screenshot of the second craft:

• Why is your fairing so long and yet so little inside of it? Is this supposed to be space for payload?
• If you have a fairing anyways and you want to reduce drag, why not put some batteries inside into the fairing instead of using those big batteries?
• And the excessive number of wings - why? Wings have a lot of drag. You should have just enough wings to have sufficient lift and not much more.
• Maybe just put all the mining stuff in a Mk 3 cargo bay
• What are those parachutes for? It's a plane after all...
• Is that a tricoupler with 3 engines at the back? There's absolutely no reason to not use a quadcoupler with 4 engines and have less radial engines instead
• If you're already using a command seat to save weight, it seems contradictory that you added a big, heavy, unmanned control unit when you could have just as well attached a lighter one.
• The same applies for the ore tank: The purpose of this plane isn't to carry large amounts of ore around. You do require an ore tank for the mining stuff, but the smallest variant of it will do the job
• Are you sure you need this many RCS trusters?

Also some advice for designing spaceplanes:

Don't put all the fuel and engines at the back. Because when you burn all the fuel, the center of mass moves very far with such designs, which also makes the behaviour of the plane change a lot during the mission and generally makes the desinging harder.

And here are some pro tips about the aerodynamic model of KSP:

• Construction nodes that aren't in a cargobay or fairing and don't have anything attached to them cause drag
  • When they are facing forward into the flight direction, they cause the most drag
  • When they are facing backwards, they cause the least drag
• Therefore the drag of a RAPIER-engine can be reduced by attaching a small 0.5-Meter-nosecone on the construction node at the back of the engine (and it also looks cool). It makes only a small difference, but it is a difference

1.Yes.

2.Maximize cargo space+batteries don't produce THAT much drag

3.On my test,this is just enough to liftoff.A little less and it will not takeoff on the runway.

4.Yeah I should have done that but forgot

5.forgive my bad plane landing skills(after all there will be an engineer to restore the parachutes)

6.I think that someone (@AeroGav?)said that quadcouplers produce 275% more drag but only 33% more engines

7.Nope!It wasn't for weight.It was just my habit(idk why either,but doing so seems right)

8.Yes it is!Some contracts want a lot of ore...(i have thinked about using only a 75 ore tank,not an 1500 one,but decided to make the contracts more diverse)

9.I dunno...I haven't used them much,so I think that we need a lot,enough to cover a delta wing.

10.Yeah.I think that thats one of the reasons that the parachutes exist.

11.Yeah.I would want to minimize the amount of them.

12.Nope!You need to use an 1.25m one.(i was too lazy to install any of them because the bulk of the drag was on the three fuselages)

[s_gamer101]

1 hour ago, jounce said:

You need to use an 1.25m one

I doubt that.

2 hours ago, jounce said:

Yes.

But once you deployed the fairing, your drag problem will be even worse. That's another reason tu use a cargobay instead.

2 hours ago, jounce said:

I dunno...I haven't used them much,so I think that we need a lot,enough to cover a delta wing.

I also noticed now that you placed them in a weird way: For pitch and yaw movements, you only need RCS trusters facing in 4 directions: Up, down, left and right
(Roll movements aren't possible with your current RCS trusters configuration from what I can tell from the screenshots)
Also, they become more efficient the further away from the CoM or rotation axis they are because they can apply more torque. With your current design, you could place some at the wingtips and some at the front of the plane.

2 hours ago, jounce said:

But that doesn't fix Poland getting to the left side!(i.e vicious cycles)

Poland getting to the left side? What do you mean?

2 hours ago, jounce said:

forgive my bad plane landing skills(after all there will be an engineer to restore the parachutes)

You could practice with a small airplane on Kerbin, it's not that difficult to learn.

Are your parachutes even sufficient for Duna landing?

2 hours ago, jounce said:

On my test,this is just enough to liftoff.A little less and it will not takeoff on the runway.

Planes not taking off can have other reasons than not enough lifting surfaces

[jounce]

7 hours ago, s_gamer101 said:

I doubt that.

But once you deployed the fairing, your drag problem will be even worse. That's another reason tu use a cargobay instead.

I also noticed now that you placed them in a weird way: For pitch and yaw movements, you only need RCS trusters facing in 4 directions: Up, down, left and right
(Roll movements aren't possible with your current RCS trusters configuration from what I can tell from the screenshots)
Also, they become more efficient the further away from the CoM or rotation axis they are because they can apply more torque. With your current design, you could place some at the wingtips and some at the front of the plane.

Poland getting to the left side? What do you mean?

You could practice with a small airplane on Kerbin, it's not that difficult to learn.

Are your parachutes even sufficient for Duna landing?

Planes not taking off can have other reasons than not enough lifting surfaces

2.I don't.Thats what that pistons for.

3.Ok I'lll try adding roll thrusters

4.ok.

5.Oops!I meant that it went to the right.

6.Yes,I could land THESE,but not something that has 64 wings and 80000 tons of fuel

7.Nope.These are kerbin only.Just use retrothrusters in anywhere else.(maybe exempt laythe)

8.I don't mean that its not taking off.I mean that it would stall.

[s_gamer101]

7 hours ago, jounce said:

6.Yes,I could land THESE,but not something that has 64 wings and 80000 tons of fuel

That slounds like a design problem

7 hours ago, jounce said:

7.Nope.These are kerbin only.Just use retrothrusters in anywhere else.(maybe exempt laythe)

And expect Eve and probably Tylo

[Lt_Duckweed]

22 hours ago, s_gamer101 said:

I doubt that.

Using a 0.625m nose cone on the back face of a rapier will only partially remove the back face drag, since it only occludes 1/4 of the back face area.  To fully remove it you have to use at least a 1.25m nose cone.

[jounce]

8 hours ago, Lt_Duckweed said:

Using a 0.625m nose cone on the back face of a rapier will only partially remove the back face drag, since it only occludes 1/4 of the back face area.  To fully remove it you have to use at least a 1.25m nose cone.

wait youre the one who made the jool ssto minus magic wings?

[s_gamer101]

9 hours ago, Lt_Duckweed said:

Using a 0.625m nose cone on the back face of a rapier will only partially remove the back face drag, since it only occludes 1/4 of the back face area.  To fully remove it you have to use at least a 1.25m nose cone.

This makes sense, but doesn't that overheat in closed-cycle mode?