What throttle do you launch on?!

[FirstSecondThird]

This is a small forum thread about what throttle you use for your Vertical ascent/Gravity Turn.

For me I start on 72% during vertical ascent to avoid overheating and possible rapid unplanned engine disassembly. Then I go full throttle to counteract Kerbin's gravity. It's completely foolproof for me, and my dorm mates in college right now because I decided to get another degree in Astrophysics. BTW please reply containing info like the kind above.

[Pecan]

100% until limited by terminal velocity, if ever.

What info?

[Frozen_Heart]

I use tweakables to set the TWR to 2 and then launch on full throttle.

[moogoob]

100%. To quote youtuber Jacksepticeye, "SPEEED IS KEEY!"

Partially joking though - I try to tweak any engines/boosters so that my wet TWR is somewhere around 1.3/1.4 so that ascent isn't too dramatic.

[Red Iron Crown]

100% almost always. I try not to over-engine my rockets.

[RSwordsman]

100% almost always. I try not to over-engine my rockets.

I end up doing the opposite-- making sure I have enough muscle to overcome air resistance met during my crappy gravity turn, then running on very low throttle for most of the launch. It's a lot easier with FAR though, so I'm getting better about not needing 5 Mainsails to get a piddly Karbonite scanner into orbit

[Randox]

I start at 100% and then start dialing it back between 100-200m, and I keep adjusting to keep myself on track with the terminal velocity. After I think about 25000m the terminal velocity becomes virtually unreachable and put the hammer down for the rest of the trip. A pretty typical launch will see throttle dip as low as 70% prior to 20,000m.

[numerobis]

100%.

If that gets me going too fast, I revert and take off an engine or tweak an SRB.

[Concentric]

With spaceplane launches, 100% until coasting to apoapse, because speedbuilding is important. With rockets, 100% until 150m/s, then decreasing throttle to bring the TWR to a little over 1, cutting it when that is no longer possible (i.e. solid boosters). I put the throttle back up when staging off engines of any kind so I don't decelerate, and also at about 30-35km I go back to 100% pointing between prograde and the horizon.

[Jouni]

At 100%. If a rocket needs to be throttled down during the ascent, I consider it a design failure.

[problemecium]

^ Same here. If the engines are too powerful at launch, then it means I can carry more fuel on that stage (or cut out some of the engines). So I floor it at launch and don't start dialing back till around 40km when I start to experience high G-forces.

[Wanderfound]

In line with others: if you're launching with partial throttle you have more engine than you need. Not that there's anything wrong with that...

[InterCity]

Always full throttle, for two reasons: If it's a rocket, its booster stage has a TWR of about 1,01. If it is a plane, then the reason is: YOLO: you only launch once

[tg626]

I use MechJeb, and it starts a 100% - my designs usually go 100% up to a few KM then throttle back to around 75% until the gravity turn where it goes back to 100% again. Rarely, it will start pulling the throttle back as I near MECO to limit acceleration to 40m/s.

[The Destroyer]

100%. I use FAR, and rarely slow down on aerodynamic rockets... I should, because they turn horribly

[lincourtl]

100%. I play with FAR and try to design my rockets so that they never need throttling.

[Torquemadus]

I set my SRBs to 70% thrust to delay their burnout until after I've cleared the dense portion of the atmosphere. This means that they give their best TWR at a point where they aren't fighting against terminal velocity. This allows my SRBs to provide a larger share of the work needed to lift my vehicle into orbit.

[Brethern]

Bare minimum required to leave the pad, I like simulating the slow movement of the saturn V on lift off.

[Immashift]

Generally I start at 0, and then work up very quickly towards 100% and stop maybe 5% above what's required to lift off. Otherwise it can be inefficient, that and things can explode.

[Aragosnat]

Depends on what I use. SRBs are always 100% throttle. But, can be set to produce lower thrust as needed. Rest of the engines are always set at 100% as I try and make sure that the engines are spaced far enough apart not to over heat and go boom.

[Cirocco]

100% all day every day.

occasionally I might put thrust limiter on my SRB's, but when launching, you floor the throttle.

These ARE kerbals after all.

[LethalDose]

For an LFO only rocket, I start at 100% off the pad, then throttle back as needed to maintain an approrpiate TWR/velocity.

For an LFO with strap-on SRBs, I thrust limit just the SRBs to provide TWR of just below 1 (usually ~ 0.6-0.9) when the main engine is shut off, so I can control my ascent with the LFO throttle. Throttle % off the pad varies with rocket and payload.

With both set-ups, I start the gravity turn just off the pad (but only ~ 5 degrees; I fly with FAR), then push over more and more as speed increases.

[[email protected]]

I build all my rockets to have a 1.2 TWR and launch at 100%. It would seem that your throttle and TWR would both be important to know. Knowing just the throttle used doesn't tell you very much. Someone who launches a rocket with a 3 TWR at 70% is still taking off faster then someone who launches at 1.2 to 1.3 TWR but at 95% to 100% of throttle.

[Pixel of Life]

Launch at 100%, throttle down immediately after liftoff to limit acceleration to 2-3 g and keep reducing power to compensate for the increasing TWR. Then push it back to 100% once I'm out of the dense air and have pitched over to 20-30 degrees.

[djnattyd]

Wait, there's other throttle settings?

I thought 100% FTW was the only one