eviator

I use a mod called PreciseNode that allows you to tweak with very fine detail the different velocity vectors of your maneuver nodes. It also shows the ejection angle of the planned maneuver. Works great with the data from Olex's launch window planner. After executing the maneuver I tend to use Kerbal Alarm clock to set an alarm halfway to the destination for mid-course corrections. In the beta, and I have to assume in 1.0 as well, there were times I would do the burn and get the encounter, but for whatever reason by the time my ship made it out there, I didn't have an encounter anymore.

This is enlightening. Pressure drops below 10% of SLP at around 13km and 1% at around 25km! My ascents are waaaay too steep.

There's no demand because it doesn't exist LOL!

While rocket design is, of course, part of the equation, finding an optimal ascent profile with only one design is a good first step. It removes that as a variable, which is part of the problem with how this thread has progressed so far.

As more of a rocket kind of guy, I like the new aero. I'm playing KSP more than I used to during beta, and I didn't realize it was partly because of the beta's easy aero model. Now it's much more challenging, and that keeps me going.

I wonder if this is the major confusion. Doing the measurements differently offers the possibility that my profile is just fine, and that I'm just not comparing apples to apples. I use the non-atmosphere numbers KER provides in the VAB and the left-over dV in orbit. Unfortunately, this doesn't help me solve my original problem, which is trying to find good general rules for construction and ascent profile.

Yeah, I'm to this point as well. Even 3,300 seems unlikely to me and unfortunately nobody is willing to share their design with detailed profile. My average best is in the 3,500 range with a streamlined rocket and essentially no payload. When trying to get stuff into orbit, I have suboptimal drag and staging, so I'm depending upon 3,800 dV to get to LKO.

That's a good guess. What part of this rocket is creating extra drag?

Well I appreciate the long response, but it's not quite what I'm looking for. I can get into orbit just fine, I'm trying to find some good rules for optimal (minimum dV) ascent profiles, thus why I tried Violent Jeb's suggestion. My average good orbit is about 3550 vacuum dV. I've tweaked my stage TWRs, I've done the SAS on prograde gravity turn, I've done the no SAS gravity turn. I've minimized drag with fairings, I've done shallow ascents (horizontal by 20km), I've done steep ascents (no gravity turn until 7k), and everything in between. Because folks have been able to get orbits with 250-300m/s less than my best, there is some key that I'm missing.

Well I tried Violent Jeb's profile and came across some issues. #1 going from near vertical at 7km to 30 degrees from horizontal at around 20km requires me to burn well off prograde, which increases drag. Should I maintain reduced thrust to maintain this? #2 I cut my engines around 50k as maintaining 1 minute to Ap puts me into the red on the navball. My Ap is still inside the atmosphere. So buring horizontally within 10 seconds to Ap causes me to flatten my trajectory while still inside the atmosphere. Eventually I'm going fast enough to flip my Ap to the other side of the planet. But since I'm still in the atmosphere with a flat trajectory, the small amount of drag is affective for several minutes. My Ap eventually drops back into the atmosphere, and the process continues. So with your suggested profile, I'm spending most of the time trying to maintain orbit inside the atmosphere. To avoid #2, I'd have to make sure my Ap is a margin outside the atmosphere before cutting engines. This means either the time to Ap has to go beyond 1 minute, or I need a more vertical profile. Either way, it does not seem like the profile you described works all that well.

Okay Jeb, I'll give this a shot. If I am correct MechJeb gives you atmpospheric dV, which is difficult to plan for during the building stage, so I've been using the vacuum dV values provided by KER. I've read on these forums that taking vacuum dV and accounting for drag, you get an atmospheric dV 15 to 20% less. Using your 3000 m/s, that would be vacuum dV of around 3.5km/s

After more experimentation, I can definitely see this. I've noticed a significant jump in total vacuum dV needed to orbit if an intermediate stage is too weak. So what atmpospheric TWR should we be shooting for in our stages?

Using all or most of the suggestions to this point my best is down to 3466 dV. That required tinkering with thrust limiter in flight to avoid getting too steep. Has anyone done significantly better than this, and if so can you post how specifically?

With more tweaking I was able to get my best orbit down to 3,550 vacuum delta-V. Staying pointed exactly prograde in the low atmosphere probably made the most difference. Procedural fairings helped a little. Using a single stage didn't help at all. The balancing point between too vertical (fighting gravity longer) and too horizontal (fighting air resistance longer) seems to be the key. I'm hard pressed to see how my best ascent so far is still at least 150 m/s inefficient. I'm still hoping someone will show a specific example of their best ascents, as so far were just giving general tips.

I didn't know they could do that. That's huge!