serious orbit trouble

[mpace1217]

allright i know this is asked a million times, and i've read all the answers. i get it start with 1.5 TWR on the pad, go till 50 m/s and make 5 degree turn then follow the prograde till orbit. I follow that and still i can't get into orbit. ive got one flt-400 with a terrier as my 3rd stage, three f-400 with a swivel, and two Hammers, around 4000 delta v so its gotta be me. I've been playing for 78 hours on this game and i only get into orbit 1/45 trys. I havent even made it to the moon yet lol, wth do i need to do? 

[bewing]

Two hammers? Are you sure you don't mean three? Since you say you have three stages, I assume the hammers are the first stage. But two is a very unusual number for a stage.

In any case, the "gravity turn" maneuver you describe is an advanced player technique to squeeze out a tiny bit of extra fuel in orbit, over launching the easy way. Forget that until you've had some practice.

The easy way to launch (especially for beginners) is straight up. A level 1 pilot or OKTO can handle it on SAS and you don't have to touch anything until you are above the atmosphere. When the ship is on the pad, turn on SAS. This locks your rocket into staying vertical. Launch at full power. Watch your Ap marker go up and up until it's about 130 km or so (you will still be in the atmosphere at this point). Turn off your engine. Wait until your altimiter reads 60km. Turn off SAS, and hit D to rotate your ship. When your ship is pointing at the horizon, stop the rotation and lock it in with SAS again. Go to full thrust. Keep on thrusting until you are in orbit. (Your SAS will gradually climb above the horizon, and for extra points you can tap it back down occasionally to be on the horizon again.)  You will need a velocity of just under 2300 m/s to be in orbit. You'll make it every single time.

 

Edited May 8, 2016 by bewing

[Harry Rhodan]

3 hours ago, mpace1217 said:

then follow the prograde till orbit.

That's probably the problem. In most cases you will have to do it manually. Keep turning carefully while you ascend. Aim for 45° at 10-15km altitude and for 90° between 30-40km. Keep your time to apoapsis between 30 and 60 seconds.

 

If that's not working you should give us a better description of your problem.

[Nich]

I think I made it to orbit with 3600 dv in this video.  It is what I would call a lazy gravity turn.

 

[LameLefty]

5 hours ago, Harry Rhodan said:

That's probably the problem. In most cases you will have to do it manually. Keep turning carefully while you ascend. Aim for 45° at 10-15km altitude and for 90° between 30-40km. 

This. 

To add a bit, give yourself a 5º AOA due east as soon as you clear the launch pad. Hold that until you're about 5,000 m, just to get out of the thickest air. Turn gradually as you ascend all the rest of the way. As @Harry Rhodan indicates, aim for 45º somewhere between 10-15km (I usually aim for 15km myself but it's a matter of taste and comfort level, as well as what your design looks like and can handle). Keep turning gently until you've turned 80º - 90º by 35km and hold that until you hit your desired apoapsis. If you hit your target Ap before you complete your turn, just cut your thrust. Set a maneuver node at your Ap to circularize. Profit.

Alternately, if you hit your Ap early, you can practice fiddling your trajectory (aiming above and below the horizon marker on the navball) to try for a direct insertion to your target orbit with little or no circularization maneuver required. It can be done - or close to it - but it's not easy and rarely worth the trouble unless you're just having fun practicing.

[Wemb]

The straight up and turn left approach isn't a  good idea, hardly ever - and while trying to do a perfect gravity turn is an 'advanced' technique, you should be able to manage a fair approximation.  Instead of sticking to the prograde dead one when you get to ~45 deg at ~15km, I'd hold at a bit above your prograde on the rest of the journey. Keep an eye on the map view and cut your engines when your Ap gets out of the atmosphere (70km) and then coast with the engines off till you get to the Ap before lighting them up again to circularise. Hopefully this way you'll come up with a good compromise between a very flat trajectory at the apex of your flight, and a straight-up trajectory. 

You might find it helpful to put on KER or MJ so you can see your Ap and time to Ap during the flight.  If you do this, after you get to ~45 deg at ~15km, try and aim to keep your ToA at about 45-sec to 1min, too much higher than that you may reach the Ap before your leave the atmosphere, too low and too low and you'll reach your Ap before you get a change to gain enough horizontal velocity.

That should get you into orbit fairly smoothly.

Wemb

[radonek]

On 8. 5. 2016 at 8:16 AM, mpace1217 said:

ive got one flt-400 with a terrier as my 3rd stage, three f-400 with a swivel, and two Hammers

Thats a bit tricky combination. fl-t400 + terrier is efficient but low-TWR combination. Your circularization burn will be long, but should not start too low because of terriers abysmal atmospheric performance. When your booster stage burn of, you should be on very flat trajectory, wait until about 50s from apoapsis with circularization burn. Your prograde marker should be almost at horizon at that point. If not, you are going up too steep. You can try to cut off booster stage as soon as your AP hits outer space  (70km) and reignite it higher up to flatten your trajectory to give terrier more working time. Almost-empty booster stages with powerful engines have quite a kick and can help you out of some less-then-optimal trajectories.

Or, shorten that orbital stage to fl-t200 and add fuel to booster stage (probably with moar boosters to offset lowering initial TWR). While less efficient, this should give you more oomph for circularization burn, making it more forgiving trajectory-wise.

On 8. 5. 2016 at 8:16 AM, mpace1217 said:

I havent even made it to the moon yet…

Well, thing with your first Munar expedition is that its going from hard to easy. Atmosphere complicates getting to orbit and helps with landing. So, leaving Kerbins air, and landing on airless Mun is the hard part. Getting up from small airless body is simple, and landing on Kerbin is just matter of having heatshield and enough chutes.