problem with spaceplane urgent

[imcute]

my spaceplane is constantly going retrograde if it is above 60m/s

making it impossible to take off

the mass center is in front of the lift center

solved

the mass center should be behind the lift center

[imcute]

so my spaceplane stopped retrograding but it started ripping off its wings on liftoff instead

autostrut on all parts already

it says node break

Edited June 27, 2022 by imcute
this thread is very noisy and chaotic due to vanamonde merges

[imcute]

so im wanting to make a non KAL spaceplane

but that means that i should not use fuel consuming "S3 Vector" engines.

and that makes the speed of the plane not enough to achieve aerodynamic stability(the combination of forces that make missiles turn prograde and reentry pods retrograde)

how can i fly without aerodynamic stability?

[imcute]

@Vanamonde

@Vanamonde

im not calling a busy admin normally but im very desperate now

[king of nowhere]

this is the wrong subsection of the forum. this is the "tutorial" subsection, where people post tutorials. you're more likely to get help if you post in questions, as this is indeed a question.

also, you have 91 posts active, by now you should be experienced enough to know that you must give more information if you want people to be able to help you. all I get is that you are trying some kind of spaceplane with vector engines and that it is somehow aerodinamically unstable. and instead of trying to make your plane stable, you are trying to fly it while unstable.

All I can tell you is that if you want to fly an unstable vehicle, you can add lots of reaction wheels to compensate for aerodinamic forces. or, you could reshape it to make it stable.

[Vanamonde]

What's the trouble the plane is having? Stability or speed or both? Pictures might help diagnose the problem. 

Also, thread moved to Gameplay Questions. 

[AeroGav]

Give us some clues please...

Does your craft blast off vertically from the pad,  or takeoff horizontally from the runway ?  Is it rocket only or jet ?

What is KAL ?  A mod ?  The S3 Vector engine is part of the base game.

If you are not allowed to use it for whatever reason,  Vernor thrusters are much more powerful than normal RCS , and can work at Sea level unlike normal RCS systems that are designed for space.

My best guess is that you're trying to build a vertical launch space shuttle type thing.   You've probably got non-symmetrical engine placement, which is causing the thing to flip,  before it gets going fast enough for aerodynamic forces to keep it straight.

Space shuttle replicas are the hardest type of launch vehicle to make.  

[Vanamonde]

Overlapping threads have been merged. 

[imcute]

9 hours ago, AeroGav said:

What is KAL ?  A mod ? 

kay ayy ell overclocking

9 hours ago, AeroGav said:

whatever reason

too much fuel consumption(s3 vector)

exploits(kal1000controller)

9 hours ago, AeroGav said:

You've probably got non-symmetrical engine placement, which is causing the thing to flip

nope

9 hours ago, AeroGav said:

takeoff horizontally from the runway

spaceplane

 

better question:how do i fly without making the air pushing it on its place

the air gives a lot of effects:one creates instability which is proportional to wing size and another creates stability,which is proportional to speed.

i cannot use the latter one due to not being able to acheive that much speed without fuel exploits that i do not want to use

so i need to minimize the former effect by(im asking for this)

10 hours ago, Vanamonde said:

Stability or speed or both

both,but not enough speed is also okay

10 hours ago, Vanamonde said:

Pictures might help diagnose the problem. 

all i can supply is some pics of planes crashing

[imcute]

okay i found out that the centers should be near and the col should be slightly behind the com by looking at tut

wee!it works!

next step is to fly it to orbit and make it able to go to nearest planet in case of fuel low

it says 7829 dv but thats the sum of a nerv and two rapiers in average

lemme try mechjeb autopilot

aww man mech jeb does not know how to drive my plane and steers it into the ocean

[imcute]

this dumb guy even tilts the wings 90 degrees

[James Kerman]

5 minutes ago, imcute said:

this dumb guy even tilts the wings 90 degrees

Great news on the stability issues! I'm not the best designer or pilot of spaceplanes but I have managed to get a few to orbit by holding 5 to 15 degrees above the horizon on the navball (depending on TWR), you should have plenty of propellant.

Edited June 26, 2022 by James Kerman
More info

[imcute]

okay changed rapier to jet engine(i have a nerv so omit oxidizer) and added an isru set,see if it can work

29 minutes ago, James Kerman said:

5 to 15 degrees

okay ill try it

i thought that we should do 45 degrees!me still learning

whoops

jet engine is not working due to lack of intake(why didnt the rapiers not work?idk)

Edited June 26, 2022 by imcute
im not dumb :)

[imcute]

okay i have a spaceplane

i have a isru set

i dont have a space plane with an isru set that launches(work in progress)

[imcute]

okay more intake,but (my centers are still in the right place) it resumes tumbling after takeoff

[James Kerman]

3 minutes ago, imcute said:

i thought that we should do 45 degrees!me dumb

Please don't say that, you are just learning and spaceplanes in KSP are something of a black art.

Just now, imcute said:

okay more intake,but (my centers are still in the right place) it resumes tumbling after takeoff

A picture says a thousand words in KSP and I'm sure our spaceplane loving members can assist in design if you have further issues. The forum itself cannot host images so we take a screenshot and upload it to imgur or google drive and then link to the image here.

[imcute]

5 minutes ago, James Kerman said:

A picture says a thousand words in KSP

yes ik

 

5 minutes ago, James Kerman said:

google drive

no

5 minutes ago, James Kerman said:

imgur

ok

maybe this would work?

https://img.kaiheila.cn/assets/2022-06/OrQ8O1LNwO19g0lf.png

problem=plane okay if it could launch,but it could not and it gains wobbling energy from zero point energy evern when autostrut on

fixed,putting landing gear on fragile wings is not a good idea

[James Kerman]

4 minutes ago, imcute said:

maybe this would work?

403 Forbidden. It may be set to private.

[imcute]

aww man

have to try replit

https://image-gallery.imcute-aaaa.repl.co

omg why is that img so big!!!

have to check how to fix img width and height

fixedhttps://image-gallery.imcute-aaaa.repl.co

@James Kerman

[James Kerman]

Okay, I see now. Adding the ISRU stuff to the front of the plane has added a lot of drag in front of the wing. You really want to keep weight and drag as low as possible for spaceplanes as you are already carrying parts for atmospheric flight that become deadweight at altitude. If you are intent on carrying the ISRU gear I'd suggest adding it into a cargo bay to minimise drag however it might be best to remove it from the design until you can get to orbit.

Another issue I see is that the NERVA is a very heavy engine for a Mark 1 type spaceplane.

17 minutes ago, imcute said:

https://image-gallery.imcute-aaaa.repl.co

While I am not very good @AeroGav is a great designer and pilot of spaceplanes and wrote this helpful guide for Mark 2 types:

 

[imcute]

okay ill make a mk3 one with a cargo bay for isru

the drills are an issue

ps:the eye on the mech jeb pod looks like a fixed space core(the guy that shouts space in portal2)

Edited June 26, 2022 by imcute

[imcute]

oh well its very big

https://image-gallery.imcute-aaaa.repl.co

@James Kerman

@AeroGav

[AeroGav]

34 minutes ago, James Kerman said:

Okay, I see now. Adding the ISRU stuff to the front of the plane has added a lot of drag in front of the wing. You really want to keep weight and drag as low as possible for spaceplanes as you are already carrying parts for atmospheric flight that become deadweight at altitude. If you are intent on carrying the ISRU gear I'd suggest adding it into a cargo bay to minimise drag however it might be best to remove it from the design until you can get to orbit.

 

The blue arrow in the  Spaceplane Hangar only takes into account aerodynamic forces from wing parts...  so putting very draggy non-wing parts at the front can mean your Centre of Lift is further forward than indicated, leading to aerodynamic instability.

From my testing ,  the resource converter (both the small one and the big one) are surprisingly low drag,  as are the ore tanks.   But the drill,solar panels, and radiators make a lot of drag, even when folded away.    Put them inside a 1.25m service bay.         The drill might be too big for a 1.25m bay.  The 2.5m bay is quite draggy. Procedural fairings are very low drag.   Maybe use a fairing as the nose cone and hide your drill inside it ?

Quote

Another issue I see is that the NERVA is a very heavy engine for a Mark 1 type spaceplane.

I disagree !  Mk1 are probably the easiest to make.   They have such little drag,  the NERVA can push it to orbit by itself very easily.   I made two extreme mk1 planes as an experiment, one with virtually no wing,  one with loads of wing.   They both went to orbit very easily.    But fitting a drill in one is hard.  Fairing maybe ?

 

[imcute]

1 minute ago, AeroGav said:

Fairing maybe

aww man fairing keep decoupled by mech jeb

https://image-gallery.imcute-aaaa.repl.co

@James Kerman

@AeroGav

Edited June 26, 2022 by imcute
speelling errors

[AeroGav]

31 minutes ago, imcute said:

oh well its very big

https://image-gallery.imcute-aaaa.repl.co

@James Kerman

@AeroGav

Two things worry me :

1.  Those engine pods at the top seem to have 1.25m engines attaching to 2.5m parts then a 1.25m  part at the back.    All axial attach nodes should have something on them - if only a nose cone - and both attach faces that meet should be the same size.   If you are joining a 1.25m to a 2.5m you should use adapter or get big drag. But ideally try to minimise size tranistions

2.  Heavy nervas right at the  back.  Nothing to balance the weight up front.  Just some fuel tanks,  which will empty out and leave your plane tail heavy.  Get RCS build Aid mod, it makes this stuff clearer.

3. That shuttle type adapter at the back can be draggy if you don't put  a 2.5m nose cone on its central 2.5m engine attach node.   FRom what i can see, you are only using the three 1.25m