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problem with spaceplane urgent


imcute
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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

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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:

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

 

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Posted (edited)

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 by imcute
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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 ?

 

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31 minutes ago, imcute said:

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

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2 minutes ago, AeroGav said:

Two things worry me :

okay thank u but i decided to continue working on my mk1 thing

problem now is,with already wings 4 times more than needed,it does not take off

4 minutes ago, AeroGav said:

2.5m nose cone

seems like old pic.

the new version has a fuel tank adapter and a nose cone

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Posted (edited)
1 hour ago, AeroGav said:

just mount a Whiplash for SSTO

 

1 hour ago, imcute said:

2 nerv and 1 whiplash

yes i used this advice

and the nervs'tail nodes are sealed by nose cones

it loses controll at 10000m and 300m/s

1 hour ago, AeroGav said:

mk1 strakes

wing strakes?or big s ones?

Edited by imcute
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17 minutes ago, AeroGav said:

Is it anything to do with fuel burning off

my jet engines are effecient

17 minutes ago, AeroGav said:

only the drill.

whoops  i would fix that tommorow(its nine thirty for me!!!)

17 minutes ago, AeroGav said:

more wing.

i mean,not "too much and it cant take off"

i mean that we only need a quarter of this wing set

18 minutes ago, AeroGav said:

Big S wing strakes

okay

18 minutes ago, AeroGav said:

Angle of Attack

no its always 10 to 20 degrees

19 minutes ago, AeroGav said:

angled up

 

19 minutes ago, AeroGav said:

bending

no

autostrut on and no wacky wing placement

i think that the problem appeared on liftoff but it was stable enough to not need adjustments.An adjustment by sas instantly makes it tumble on yaw axis causing it to tumble on other directions too

elevons are bad for yawing :/

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3 hours ago, AeroGav said:

not the same thing

whoops i gave u what the navbol sez

thats pitch

1 hour ago, Vanamonde said:

merged. 

whoops i will try not to create

1 hour ago, Vanamonde said:

Overlapping threads

 

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Posted (edited)

should i put a KAL ferry to every planet that has atmosphere to compensate the bad isp of atmos nervas?

On 6/25/2022 at 9:45 PM, king of nowhere said:

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.

ur saying the opposite

Edited by imcute
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6 hours ago, AeroGav said:

no oxygen

makes me think of eve

can nervs work on eve(expecting a no)

if not how can i compensate(helicopter?)

6 hours ago, AeroGav said:

Where are your vertical stabilizers

whoops omitted that tail fin due to driving away my col

ill add them back

bc now i know that i do not need my nose cone col com all at one line,i only need to make my col slightly behind com and it does not matter if its up or down

6 hours ago, AeroGav said:

twice as many nervs as jet engines.

okay then i would triple the nervs too due to finding out that one wiplash can't get me anywhere

6 hours ago, AeroGav said:

only pitch control surface

no but i should remove them or take them far away from com

6 hours ago, AeroGav said:

The solar panels are still not in service bay

okay ill fix it

6 hours ago, AeroGav said:

old pic

yes the latest pic has a big s wing strake for roll controll and pitch controll which you mentioned:

6 hours ago, AeroGav said:

In the last pic you added a pair of shuttle vertical stabilizers

 

6 hours ago, AeroGav said:

Using KAL intake exploit on NERVs  so they work better in atmosphere

that is confusing me

nervs do not need intakes

you are either wanting to overclock the nervs(bad idea,bad isp)

or wanting to use underclocked intakes so jet engines work in space(unfortually does not work,the jet engines work just like in eve and does not get oxygen)

6 hours ago, AeroGav said:

I don't put them on until i am at 17km

yes i have 2 motion groups for them one is for closing the jets and opening the nervas and another is for opening the jets and closing the nervas

6 hours ago, AeroGav said:

On Duna,  the atmosphere is so thin, the NERVAs work great even at surface

okay but this advice does not work before i take my plane to orbit

6 hours ago, AeroGav said:

 I don't think you need such a big solar panel

i need to open my 30watt isru converter(lf only)

the other things would be powered by 8 plutonium orbs like the ones on new horizon

7 hours ago, AeroGav said:

This is difficult because i think it is night time where i live when it is daytime where you live.

unfortually yes :/

we have to bear the time zone problem

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8 minutes ago, Zacspace said:

Is this your first SSTO?

no but it is my first ssto that has to run on planes instead of kal powered vector engines

8 minutes ago, Zacspace said:

can fly to orbit and back with 1 or 2 rapiers and no other engines.

aww ok

 

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aww man my plane runs out of oxidizer rilly fast

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

a plane did not have any nervae,this is what happened to its orbit

so i launched the plane and keeped it at <5 degrees pitch

but then the wings went on fire and i had to get 20 degrees of pitch to lift higher to avoid the same thing thats causing fire cause drag

and then when the wings are no longer on fire,<5 degrees of aoa

and it worked fine

at 20000m,i had to switch to rocket mode and it worked even better

then oxidizer ran out and i get a suborbital trajectory with apoasis 248km(due to not looking at the map frequently enough)

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8 minutes ago, imcute said:

aww man my plane runs out of oxidizer rilly fast

It looks like you still have half the tanks filled with liquid fuel, if you remove some of that it will make the vessel lighter and easier to get to orbit. It looks like you are getting to orbital speed so I think you're nearly there. By the way, that's a great looking design! :happy:

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Just now, James Kerman said:

orbital speed

NO!

orbital speed is three times this speed(1000m/s)

1 minute ago, James Kerman said:

, if you remove some of that

okay

1/3 fuel removed(most from fat wings)

lemme test it out

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