Xeldrak

What did you do in KSP today?

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Posted (edited)
14 minutes ago, Space Nerd said:

with a single standard carnard on it

If that canard (pair?) is situated nearer the nose than the tail, that will likely be your problem...  nothing to go on without a picture/schematic though.

If you want tail fins on your first stage, then you'll need bigger ones on your second...  rough rule.  (or else get tricky with the solution.)

In the case one has a lot of wing area on the first stage (but this is not not your case), it can be necessary to restrict max speed on lift-off until reaching > ~20km and much thinner air, or staying on a vertical heading longer to get there.

A good analogy for a rocket is an arrow: big chunk of heavy metal at the nose and feathers at the tail.

Edited by Hotel26

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I forgot to mention that I started building my first space station! I managed to get the first module in a stable lko, but when I tired to dock the second module, I was off by three kilometers. Not too bad for never watching a tutorial video.

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1 hour ago, Hotel26 said:

If that canard (pair?) is situated nearer the nose than the tail, that will likely be your problem...  nothing to go on without a picture/schematic though.

If you want tail fins on your first stage, then you'll need bigger ones on your second...  rough rule.  (or else get tricky with the solution.)

In the case one has a lot of wing area on the first stage (but this is not not your case), it can be necessary to restrict max speed on lift-off until reaching > ~20km and much thinner air, or staying on a vertical heading longer to get there.

A good analogy for a rocket is an arrow: big chunk of heavy metal at the nose and feathers at the tail.

The fin is pretty much on the tail, but not quite (have to save space for the legs), so should I put bigger wings near the top?

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Just now, Space Nerd said:

so should I put bigger wings near the top?

No.

A picture is worth a thousand words...

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1 hour ago, Hotel26 said:

If you want tail fins on your first stage, then you'll need bigger ones on your second...  rough rule.  (or else get tricky with the solution.)

???

1 minute ago, Hotel26 said:

A picture is worth a thousand words...

As I said, I will try to take a picture tomorrow.

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1 minute ago, Space Nerd said:

???

OK, here's the deal.  fins, wings, canards generate lift but they also generate drag.  the drag is roughly quadratic with speed and quadratic again with angle of attack.

that means that if you put a knife edge on your capsule it may have next to no drag to begin with.  And you can hold SAS vertical starting from a stable position with very good accuracy.

As soon as you attempt the turn, or even just really start to attain rocket-like speed, but especially the turn requires an angle of attack.  Once that gets started, it's likely to oscillate as SAS tries to compensate.

Once your draggy fin at the nose of the ship catches the air, it will drag the nose into the flip.  That's why an arrow has the feathers on the tail.  So if I imaging your canard is near the nose, your arrow is going the wrong way.  If you've got it nearer the tail, it's not your cause.  but if it's at the tail of your first stage, then it's probably still in the top half of your rocket.  You really don't want drag at all but it's the price you are paying to get control surfaces to help you aim.

So the big question here is "what is your objective in placing the canard?".  But let's wait until you get the pictures up and then everyone can discuss this reasonably and offer some better advice than I am doing.

Have a good evening.

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I added the canards because my lander also flips over when it's not pointing straight up without the canards , so I added them to try to fix this, and they're almost at the bottom of the rocket.

7 minutes ago, Hotel26 said:

Have a good evening.

It's midnight here.

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Just now, Space Nerd said:

It's midnight here.

And here.  00:22

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Posted (edited)
17 minutes ago, Space Nerd said:

I added the canards because my lander also flips over when it's not pointing straight up without the canards , so I added them to try to fix this, and they're almost at the bottom of the rocket.

Ah, OK.  Still guessing in the dark but the concentration of weight in your rocket might be at the tail.  If you know what CoM (Center of Mass) and (Center of Lift) are, then you want to have your CoM ahead of your CoLCoL generally refers to wing lift, but there's a center of pressure, I think that covers all kinds.  If you're fuzzy on what they are, read up on them when you can.

14 minutes ago, Space Nerd said:

(I'm in Taiwan)

Perth, Australia

Now my bedtime.  CIao.

 

P.S. you are on the right track with the canards.  You have them in the right place!  They're just not powerful enough to do the job.  Try bigger fins and work your way up through larger ones as you need..  On some craft, I've had to use spaceplane wings as fins!

Just remember bigger fins means more drag, so you want to use the smallest that will reliably do the job.  Good luck!

Edited by Hotel26

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3 hours ago, Space Nerd said:

Built my first Eve lander prototype, flies like a charm when the SAS holding at radial out, but flips over as soon as I started the gravity turn [...]

Just a random thought, sorry if it's a stupid suggestion. :rolleyes: A first guess is that maybe you are turning too much? What would happen if you would keep SAS to "surface prograde" instead (once you get some speed, and after doing a very minimal push to the desired ascent direction), to minimize the aero drag forces?

That's what I'm sometimes doing with very heavy and not particularly aerodynamic rockets. It makes it sligthly difficult to control the heading, though.

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I finished iterating on a SSTO spaceplane that will travel to Laythe :

1t61b7Z.png

This SSTO uses plasma propulsion powered by a nuclear reactor (thanks Nertea for NF !). It has over 3 km/s of delta V from LKO (it uses classic LFO for getting up there), +3 more thanks to the auxiliary lithium tanks visible at the back (launched by a conventionnal rocket). This SSTO is also a VTOL (using some B9 engines, a bit OP I would say) and has 2.5m ISRU stuff. That's my current "ultimate" ship. I use FAR, wich make sea plane design a nighmare, that's the reason why I took the VTOL path (the floaters under the wings are just here to make the plane more controlable on water, but they are below floating line when fuel is full).

It will be my first go in the outer Kerbol system, despite having played for quite a long time. I usually don't warp time for more than a few weeks at a time, and I launch many missions in parallel (thanks KAC !). It results in a slow progression, and a vast majority of Mun/Minmus missions. I decided it was time to go further, so I lately launched quite a few interplanetary missions (Duna, Eve, Jool). I will time warp more from now on, to discover those other worlds. That save is on 1.7.3, and I want to move on (I got breaking ground a while ago but I'm still playing without it, and JNSQ is quite attractive :wink:).

 

And one more picture, not from today, but I wanted to share it : an illustration of the fun & pleasure of fast-roving on the Mun (prograde SAS & RCS are your friends to stay alive after a rover jump :sticktongue:):

8g0FMzK.png

 

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Posted (edited)

A trip to Minmus for a contract to plant a flag on it. Did a bit of science as well and got Shannon Kerman here for her science tasks too for another contract. Been here dozens of times in the past few months and I just love this little satellite. Did some improvements on my Basilia starship as well.

triptoBasilia.jpg

Also over 6 months now since last October for playing KSP with well over 1000 hours... woot!  :0.0: 

Edited by Retro Starship

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Posted (edited)

I lost my Minmus ore transport. Apparently, MJ Landing Autopilot didn't start its final burn soon enough - resulting in the craft crashing down on the surface hard. Here is a picture of the ore transport spinning around half a minute after impact.

 

e3C1efu.png

 

I have a "light" ore transport ready in the VAB, but I'm in no hurry to send one up to Minmus. Besides that, I have a few other things in my career save to deal with such as:

  • Semi-annual budget check
    • I really need to catch up on the spreadsheet
  • Getting the Neptune VII to:
    • Refuel on Bop
    • Doing crew reports over Jool
    • Landing on Laythe
  • Planning my next extra-long tourist run.
    • So far, it's going to be in a Poseidon SSTO called Rerun.
    • Hopefully it doesn't go as long (or turn out as agonizing) as the Raven-Remembrance saga
  • Testing the T-6 Cannonball SSTO on Duna
  • Tourist run to Ike in a private spaceplane.
  • Planting a base on Eeloo
Edited by Mars-Bound Hokie
Added more items on my to-do list

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8 hours ago, Lewie said:

but when I tired to dock the second module, I was off by three kilometers.

All you need is some RCS to get close.

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Posted (edited)

I finally got into LEO from 1.9 km ASL (took  around  3 tries) with my newest Eve lander prototype!

t3T4ihs.png

In VAB:

KCABCQk.png

The core stage wobbles really badly (not as bad with boosters attached), which might cause a lot of dv loss, can anyone help?

2Q5lS30.png

craft file:https://www.dropbox.com/s/42qmgo2ancoroc2/EVE!!!!.craft?dl=0

Edited by Space Nerd

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2 hours ago, Space Nerd said:

[...]

The core stage wobbles really badly (not as bad with boosters attached), which might cause a lot of dv loss, can anyone help?

[...]

craft file:https://www.dropbox.com/s/42qmgo2ancoroc2/EVE!!!!.craft?dl=0

Short version: MOAR STRUTS !!! :cool:

Long version:

You have high towers made of small fuel tanks. They tend to be very wobbly indeed. You might try swapping some of the small FL-T200 tanks to some large FL-T800.

You may add some struts. For example lead them from the tops of the side boosters to the main booster column.

This might help.

I also suspect that with these struts you may no longer need so many reaction wheels.

 

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Posted (edited)

I should say it more clearly, the problem with my craft is it really wants to flip over.

Edited by Space Nerd

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Career Mode (First time player too)

Finally landed and returned Valentina from Minmus. (about a week to 10 days, on and off of efforts)

 

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58 minutes ago, Space Nerd said:

I should say it more clearly, the problem with my craft is it really wants to flip over.

Just as an experiment, put 4x spaceplane wings on it, mounted as low down as possible.  See if it still flips (it won't). That will be overkill, so then scale back.  Try delta wings, for example.

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1 hour ago, Space Nerd said:

I should say it more clearly, the problem with my craft is it really wants to flip over.

Oops... :D Then my struts won't help much. But I see the centre of mass being quite low. Maybe if something heavy would go higher, then it would help? Sorry for the noise. :sealed:

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My first prototype does wobble by a lot, but that one has a lot of autostruts.

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42 minutes ago, Stosh said:

Career Mode (First time player too)

Finally landed and returned Valentina from Minmus. (about a week to 10 days, on and off of efforts)

 

Woho! That's something!

I'm designing a Minmus lander right now. None of my Kerbals have been there yet.

And welcome here, Stosh! :)

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6 hours ago, Space Nerd said:

I should say it more clearly, the problem with my craft is it really wants to flip over.

Two comments: if you want help with designing your ship, then why don't you start a thread in the Gameplay Questions and Tutorials subforum? That's what it is for. The other is that I guess your vector engine is oversteering which makes it hard to hold a direction. I suggest that you try limiting the gimbal range on the vector.

6 hours ago, Stosh said:

Finally landed and returned Valentina from Minmus. (about a week to 10 days, on and off of efforts)

Congrats! And you sound like you didn't forget to bring parachutes. (Which puts you one ahead of me. ;))

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Today, I've landed on Proxim:

C3O2riy.png

CWslTZd.png

lNZYTWX.png

Now, it's one last moon to visit - Kohm - and this mission can finally head back home.

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