New player; How to get to orbit with the Dv suggested in the Dv Maps?

[MoridinUK]

Ok so the latest delta v maps for 1.04 and thus 1.05, suggest an efficent lift to 80km LKO is 3400dv.

SO the problem is my flying.  At the moment I can build a rocket with enough dv to get to orbit, but I can't get it anyway where near!  I'm not pushing past at-mos efficiency but i'm not close to it either.  I'm in my early career and this is my first time back since 0.9 so the atmosphere is er fun.  I can't make good gravity turns, the rockets fly out of control and even Jeb can barely hold em.

Does anyone know really good vid of a 3400 dv lift to orbit, using only the basic rocketry parts? (Actually I think I have it unlocked to the fl-200 tank and the lt-45 engine.  I don't have the inline stabiliser unlocked yet.

I know this is an easy question, but I've tried searching youtube and can only find vids of people doing it in more advanced rockets or in much earlier versions of ksp!

help!

Edited December 11, 2015 by MoridinUK

[Rocket In My Pocket]

Your rocket is flipping during gravity turn? Have you placed any fins on it as stabilzers? (They should be at the bottom of the rocket ideally)

Can I ask at what height you're beginning your turn? Do you have SAS enabled?

Also, do you use the "soft control" mode? (You press Ctrl to engage it, it makes the controls less twithcy)

Edited December 9, 2015 by Rocket In My Pocket

[rocketbuilder]

Firstly fins are needed. Your center of lift needs to be below you center of mass.

Secondly you can't do go up and turn right at 10 km. As the atmosphere has changed, your gravity turn needs to start immediatly, be at 45 degrees at 10 km, 25 at 20 10 at 30 and have MECO at about 50. Turn over gradualy and your rocket NEEDS TO BE AERODYNAMIC!

[MoridinUK]

SAS is enabled.  I have some of the first fins they give you, near the bottom.  I have tried starting very low, and at the usual 7500m, it still either flips out, or fails to get to orbit.  Hence why i'm looking for a guide or vid that will tell me what I should be doing when.  it's a basic rocket, one big booster, then a lt=30 wit 3x 200 tanks and then an lt-45 with 2 tanks.  DV is about 3600 I know that doesn't leave a lot for error, but I can't get close to orbit. AP 90k PE, -470k is the best so far.

[Rocket In My Pocket]

if your AP is 90, that's a touch more than you need, you can flatten out your trajectory at between 75 and 80 and start burning horizontally for orbit.

A picture of your rocket wouldn't hurt, it could be very draggy for example?

My only other suggestion is to execute the turn VERY slowly, like just tapping the key once every few seconds, I've had a few unstable rockets that just needed a really careful turn to not flip.

Edited December 9, 2015 by Rocket In My Pocket

[rocketbuilder]

De-remember every 0.90 thing about gravity turns!

[Rocket In My Pocket]

As far as a current video from 1.5.0 covering making orbit with very early parts, considering it's so new I don't think your gonna have much luck finding one atm...

Have you considered exploring more of the biomes on Kerbin to gather more science so you can get an actual control surface? That would really help you keep control of your rocket during ascent.

Your main problem atm imo is that you have no way to control the rocket except the very minimal reaction torque the command pod has.

[MoridinUK]

I try to do it slowly, but it needs a lot more than a tap every few seconds.. 

MECO is?

Thanks for the advice, I think the thing is just too tall huh?

Edited December 9, 2015 by MoridinUK

[rocketbuilder]

Ok, you probably need to research the better fins first and put them right at the bottem.

I'll try and make good vessel for your tech.

MECO is Main Engine Cut Off - so when you shut down your enginel 

 

So you want orbit just?

Edited December 9, 2015 by rocketbuilder

[Randazzo]

Most importantly, don't do your gravity turn like 0.90. It's no longer "Hit X altitude and turn 45 degrees", if you do that it will flip you out. Start very gradually @ ~100m/s or 1000 meters altitude and keep it within a few degrees of prograde.

That rocket there also appears to be a touch overpowered, probably resulting in going too fast. You could drop that SRB altogether by adding a bit more fuel and still have quite a sufficient TWR, or you might be able to keep the SRB and eliminate the LVT 30 stage entirely with more fuel for the 45, which gimbals, helping quite a bit with control.

[Hannu2]

Your first stage should have about 2000 m/s dv. Then you can make staging at about 30 km where aerodynamic forces are quite negligible. Solid boosters are not very cheap anymore and their thrust profile is typically not suitable for only engine (at least it is difficult for beginners). Use Swivel and two smaller SRBs if needed. Put fins only at bottom of the rocket. Small fins you have used are good. Second stage does not need fins if you stage at 30 km. It can use Terrier as an engine if you have it. It saves mass and cost.

[MoridinUK]

Ok so things to learn, going too fast doesn't just mean exceeding atmo effic?  Cos this thing never gets close to atmos effc! 

Yeah I am trying to just get to orbit and probably back, but I want to learn to do it efficently.  When I start hauling sats and trying for mun I need to not be wasting stuff on the lift to LKO.

I'm not trying to turn to 45 at 10km, I'm trying to turn a little at the time, but this rocket, if left alone with sas on pointing straight up, eventually starts to flip out.  The only non symmetrical part is the comms at the back on top (and a Kerbal Engine computer).  It kinda needs more attitude control... (and I need more flight practice!) 

 

40 minutes ago, Randazzo said:

That rocket there also appears to be a touch overpowered, probably resulting in going too fast. You could drop that SRB altogether by adding a bit more fuel and still have quite a sufficient TWR, or you might be able to keep the SRB and eliminate the LVT 30 stage entirely with more fuel for the 45, which gimbals, helping quite a bit with control.

I'll certainly be giving these ideas a try!  and well all of the advice really!

[rocketbuilder]

Yeah, what tech do you have?

Edited December 9, 2015 by rocketbuilder

[Rocket In My Pocket]

I may be crazy but the 2 Goo Canisters you have mirrored on top may be counter-productive to the triple fin setup you have, they may also be causing extra drag, I've had some weird problems in the early game using a similar setup. You could either try a 4 way fin setup (On the same axis as the 2 canisters) or perhaps go to 3 canisters in the same pattern as the fins.

I may be way off base, but it could be an issue of asymmetrical drag? Some thing about it flipping over on it's own makes me think somethings off in some way.

Best of luck! Keep us informed, I'm sure we're all rooting for you.

[MoridinUK]

Tech: Start, Basic Rocket, General Rocket, Eng 101, Survivability and basic science.

Not sure about the goo canisters and the fins, it could be worth trying out, though I'd have to move my comms, and the engineer.  Actually I could drop the comms anyway, originally it did have a service bay with some batteries in it, to make comms worthwhile.  But I ditched that for move dv... 

[Rocket In My Pocket]

Just made orbit in 1.0.5 (Barely, didn't have enough fuel to get back lol) in this:

I definitely had to take my gravity turn really easy, I also didn't bring along any Science stuff, I'm going to try adding goo canisters and see what happens.

Ok so yeah, the addition of 2 canisters to the command module made it quite tippier than before. I would definitely add a service bay and place the 2 canisters inside.

Edited December 9, 2015 by Rocket In My Pocket

[MoridinUK]

Oh I shall play around some more... I just got a 83k PE, -160k Ap with my rocket as posted, but with 3 goo canisters.. Service bay here I come..  LT-45?

It took holding the eastward key to keep the rocket straight during the bacc's burn. if I did nothing Jeb still couldn't stop it verring westward somehow.. 

[Rocket In My Pocket]

You want to head out over the ocean, to make this easier pick the whole rocket up in the VAB via clicking the command module and rotate it so that window is facing opposite to the open doors of the VAB. (the way it looks in my picture) so you're headed the right way from the get go.

At 10km start your gravity turn very slowly and carefully, if you spin out or flip try dropping the throttle to 0 and re-orienting before engaging again. Once you're AP is 80km you can cut throttle and level out your ship horizontally so your running parallel to the planet, then once you reach around 75k go full burn until the orbit circularizes and the PE is 80km. (It may appear to suddenly swap places with the AP, that's ok)

The important thing is to be behind your AP as if your pushing it along with your nose, keep an eye on the time till AP, and try to keep it between 5-15 seconds if it gets to high, nose down, if it gets too low; nose up.

Hope that helps!

Edited December 9, 2015 by Rocket In My Pocket

[Rocket In My Pocket]

8 minutes ago, MoridinUK said:

Oh I shall play around some more... I just got a 83k PE, -160k Ap with my rocket as posted, but with 3 goo canisters.. Service bay here I come..  LT-45?

It took holding the eastward key to keep the rocket straight during the bacc's burn. if I did nothing Jeb still couldn't stop it verring westward somehow.. 

Can I ask if your using mouse/keyboard or a game controller? I can't imagine why the rocket would veer so sharply one way for no reason.

When the craft is flying and you aren't pressing anything at all what does the area circled in red look like?

Are any of those arrows off center? That means the SAS is trying to adjust for some imbalance, could explain the veering?

[justidutch]

No no no - don't start your turn at 10km!  I Start mine very gradually when my speed reaches ~70 m/s, which usually translates to about 800-1000m.  And don't go too fast either.  Do some testing (in sandbox) to determine how fast you should go at which altitudes to maintain a decent amount of control and stability during the gravity turn, then tweak the thrust on your SRBs accordingly.  On well designed rockets they will almost do the turn themselves with very little 'steering' needed.  If my rocket has reached about 20km, is pointing about 45 degrees over, and is going > 400m/s, it will most likely turn out to be a very good flight path.

Edited December 9, 2015 by justidutch

[Rocket In My Pocket]

13 minutes ago, justidutch said:

No no no - don't start your turn at 10km!  I Start mine very gradually when my speed reaches ~70 m/s, which usually translates to about 800-1000m.  And don't go too fast either.  Do some testing (in sandbox) to determine how fast you should go at which altitudes to maintain a decent amount of control and stability during the gravity turn, then tweak the thrust on your SRBs accordingly.  On well designed rockets they will almost do the turn themselves with very little 'steering' needed.  If my rocket has reached about 20km, is pointing about 45 degrees over, and is going > 400m/s, it will most likely turn out to be a very good flight path.

Not to disagree but I just tested it on the very simple rocket pictured above, and it didn't even make it to 80k, let alone a stable orbit?

At 1000m you're spending way to much time in the thickest part of Kerbin's atmo wasting valuable thrust on horizontal movement you don't need yet.

Can you prove your theory somehow? I mean the exact same rocket makes orbit when beginning the turn at 10km but not even close when starting at 1k...I even cheated and added actual control surfaces!

[Sanic]

Gimballing helps.

[justidutch]

I have not tested on the rockets pictured here, the guidelines I mentioned are what my normal targets are for my ships.  Yes, they will vary on a case-by-case basis, but I have personally found the numbers I listed to be the most efficient way to get to a stable 75km orbit.

[HvP]

Judging by your thrust and ISP data in that KER screenshot I'm guessing you have the "Reliant" LV-T30 installed in your second stage instead of the "Swivel" LV-T45 in your second stage. The "Reliant" has no gimbal control and at those speeds in atmosphere your command pod torque will not be able to compete against the aero forces. So, if you haven't nailed your gravity turn perfectly - perfectly - you will have no margin to compensate.

I'd suggest making sure that you are using the LV-T45 "Swivel" in your second stage for maximum control.

[WuphonsReach]

I can get a reliable 3500 dV to 85km orbit out of MJ with the turn starting at 3500m, by around 30,000m it's at least 45-60 degrees and from 45km upwards you're pointed almost horizontally.  Starting TWR is usually around 1.3-1.6, second stage has a TWR of 1.0.

(MJ setting of 3.5km or 100 m/s to start the turn, final flight path angle of 1 degree and turn shape of 60% with a target altitude of 85km.  I've done enough by-hand launches, I just let MJ do it now.)