Wobbly Av8r

In the Debug Menu (where you accessed the physics values) under Physics>Aero is an option similar to Display Aero Data in Action Menus - then when you select the part with Right-Click (PAW) it will be under the Debug text at the bottom. Glad you found out what it was - more than happy to help flatten the KSP curve when I can...

Don't know if it helps, but the pastebin file was a .txt file that I simply saved as a .craft file to use; it did so with the following two errors - I wonder if either one might weigh in on the issue: Vessel X-AC-6 is missing part module ModuleB9PropagateCopyEvents Vessel X-AC-6 is missing part module ModuleDockingNodeNamed Neither error seemed to have any negative effect on the trial runs.

Yeah, I get the high drag on the Covert-O-Tron as well, but it doesn't seem to hinder the general performance... things that make you go "Huh?" Well, there's always the ol' verify the integrity of the files (Steam has a convenient way to do that, not sure what to do with other platforms) but nothing else seems out of place. Wish I could be more help, but I'll just have to keep poking around...

Again, FWIW, your physics settings match my settings (aka Default) perfectly.

Re: Pasting image... use the BBC Code, but remove the "img" "/img" coding (including brackets] is what I've found works. Should be a .jpg file, not a link to address at imgur. I can only offer a couple of comments: First, what are the two mods I see above KER on the right? If one of them is FAR, that could be part of the issue. Second, you're at 1000 m even though you don't have a lot of pitch, it really, really makes a difference to keep it low (you see 300 m in my image), the lower the better until you get up around 700+ m/s. Also note that I am at 300 m at 1:08 Mission Elapsed Time, i.e. keep low, low, low until you get that speed - and therefore thrust - higher.

Here's your SSTO at 800 m/s and numbers (intake, RAPIER)

Yeah - you've got something restricting your thrust output - I'll post "nominal values" for the PAW menu here in a few minutes... I got 210 kN right at Mach 1. Something, either a mod or your settings is preventing you from exceeding Mach 1. If you stay level, you should have no problem continuing to accelerate right past 330 m/s. Stay as low as possible - you did retract your landing gear, right? [I was still able to exceed Mach 1 with the gear down, so scratch that... The flow should get up to over 2.4 or so if I recall correctly ]

Right-click on one of the RAPIERs and watch the thrust in kN, about 4 or 5 lines down from the top of the Parts Action Window. When you takeoff, you press Z for full thrust and then the space bar (activating the stage). You should see the thrust continually increase to ~400 kN before pulling it up to 15-20 deg to get out of Kerbin's atmosphere. When the PAW indicates a gradual decrease to 180 kN, switch modes (the 180 kN is what you get from closed cycle mode, otherwise it will continue to decrease below 180) Yes - the X-AC-6, correct? Look around the PAW to see what is limiting your thrust, because the intakes and design in general did not have enough drag to slow it down. I did NOT light the LV-N engine at all. The "limit Q" is one of the settings of MechJeb autopilot and automatically throttles down engines to prevent high dynamic pressure (whatever you've chosen, but defaults to just below Mach 1), but don't worry if you don't have it installed...)

Not sure what to tell you, @chris-kerbal. I just literally took off, stayed about 200-300m above the water at full thrust, accelerated straight-away to over 700 m/s and climbed until about 16,000 m, used your "0" Action group to switch to Closed Cycle, but ran out of fuel before being able to achieve LKO, FWIW. The .craft I flew had an error but what loaded flew the low profile no problem... Do you have like a MechJeb set to "limit Q" to some lower value? Even when the autopilot is not engaged, it can mess with your throttle setting... Are you familiar with monitoring the performance of the RAPIERs using the PAW menu?

With R.A.P.I.E.R.s accelerating in the low, thick atmosphere is key - once you get up to speed, they produce a great deal more thrust. Immediately after takeoff, stay very low and level (any climb will reduce your ability to get fast enough) while accelerating - once you get past Mach 1 (~330 m/s down low) you will start generating more thrust - they put out the max output between Mach 3-4 (3.75?) Somewhere around 19,000 m you'll want to switch them over to Closed Cycle and complete the climb into LKO. YMMV, good luck! [ I downloaded and flew your SSTO - had no problem accelerating to 700+ m/s before pitching up to ~15 deg and continuing to accelerate. If you activate one of the RAPIERs PAW, switch over to Closed Cyble when you thrust = 179.5 kN... ]

Yes, @chd, I've mounted Terrier engines to swivels at the end of telescoping poles, connected to alligator hinges (not on a dare, but so that the package was streamlined for launch through the atmosphere and then telescoped to maximize their torque for the exact same application - steering an asteroid!) Recommendations: Don't use Autostrut on ANY robotic part - or Rigid - they fail sporadically and unpredictably. For this installation the 60 kN per engine does not seem to tax the components at all. I had no problems with either the Lf/Ox engine or the RCS system fuel feed.

FWIW, I think the video that you've linked to/refer to is more about the strategy/sequence of getting the science as well as which tech tree branch to unlock first to get the greatest amount of science in the shortest amount of time, but not how to build or fly the rockets that actually accomplish the task (which is why it is so sped up and lacks details of the rockets or the technique used to get to the various destinations). TL;DR: Use the video as an example of "How to Get Science Very Efficiently By Using These Experiments at These Locations", not as a "These Rockets Will Get You Science Quickly".

I've had the same problem on a less stressful level - a rover with a claw. I got the type of feedback loop that @OHara describes and couldn't figure out why my rover went nuts after attaching the claw to pod... the pod with its own reaction wheels and orientation, but no electricity until I attached to it... Once I disabled the reaction wheels of the scrap pod, all was well. Something in your 500+ part vessel is creating a ressonance... and your problem - maybe something that wasn't powered before.

Not sure of the size/power demands of your helicopter, but my experience is that the turbine motor is a real pig when it comes to fuel - you may be better off going electric and placing a fuel cell or two to supply the energy - in a recent thread, I discovered that using the smaller -16 sized electric motor, I was able to raise a simplified co-axial machine from the surface of Eve to 25,000m on 11 kg of fuel. While your requirement may be for the more powerful motors, I would think that electric + fuel cells will at least resolve your fuel consumption issue.

So, build your rocket and include a KAL-1000 controller, go into the Actions window. In the Action Groups column, select KAL-1000 controller, which places that heading in the Group Actions column. Now select the engine (highlights in blue), this will add options to the Selection column, and you will select <Thrust Limiter, which will place that option in the Group Actions column. You can leave the Actions window and go back to construction, open the PAW for the KAL-1000 and click "Open Editor", which opens the editor window. First click on the name of your engine so that that part's window is active, place cursor over the far right dot, click and drag it to the top. There is an empty circle next to it after you do this. Now click in that open circle and drag up and outside the entire editor window - the transition to that point is now well above the normal limit and the left dot should show the line connecting the two points that was previously horizontal into a steeply climbing or vertical line. Close the editor. Make sure you activate cheats infinite propellant and indestructible (heat, joints, etc.). Open KAL-1000 PAW and hit play so that it plays a few seconds, then hit pause. It's primed for thrust limit to be something above the norm... hit Z, [space bar] and enjoy. Note: the video claims it is unlimited upwards (maybe) but if your values are too high, my experience was that the vessel will NOT stay intact... so you may want to find some happy medium. Good luck!

Well, on a head-to-head comparison [ Okto2 probe + battery in 2.5m identical streamlined fairing, Large Advanced Reaction Wheel and an inert Jumbo-64 tank payload, the Twin-Boar vs. Mainsail+Jumbo-64 launched with Radial Out SAS ] The cost for the Mainsail is ~10% more expensive out of the gate; While the Mainsail wins the Isp comparison (285s - 310s) to Twin-Boar's (280s - 300s)... ...the Mainsail produces less thrust (1,379 kN - 1,500 kN) than the 'Boar (1,867 kN - 2,000 kN), which results in... ...(when launched from KSC with identical payloads) the Mainsail lifts its payload to 73,000m while the 'Boar achieves 79,500m. (~9% higher) The weight distribution/aerodynamics of the 'Boar allow reentry with natural stability, i.e. no airbrakes or such necessary for engine-first descent profile. The entire tank/engine combo of the 'Boar has 20 m/s impact tolerance, the Mainsail combo 7 m/s on either; 2 parachutes (weight & cost) are all that's needed to recover even on land. On a cost per kg basis, I think the 'Boar wins and the "easier" recovery (required equipment, impact tolerance) seal the deal for my space program which reuses the boosters I use to put my payloads in LKO. I've explored the drag profile of the 'Boar extensively, but not the Mainsail - the 'Boar is interesting in that it has high drag until Mach 1 and then reduces quickly - not sure how that plays into the comparison, but the head-to-head comparison still validates the overall performance of the 'Boar. Let me know what you think...

No disagreement that there are a LOT of different ways to get things done and I will look into what you described - I'm sure it will help my designs down the, uh, 'road'. But all said and done, your quote about TWR is essentially what I was trying to convey to @chd and anyone else following these types of debates - the TWR is more of an indirect result than a primal factor. In this case the TWR was preempted by considerations of efficiency, allowing optimal recovery, ultimately making the cost of lifting 43+ tons into LKO cost a meager ~23,000 due to the "recovery friendly" properties of the Twin-Boar booster! All said and done, I appreciate your feedback and the conversation. [Edit: OH! And I HIGHLY recommend the DLC Breaking Ground - the whole franchise has been worth every penny!]

If you go into the Tracking Station, all you need to do is zoom out until you see more than just Kerbin, double-click on the celestial body in question (you can zoom into it now and take a long look) and then on the bottom right click one of the information tabs - either Resources, Information and one other - just the essential information here. There are little blurbs in the KSPedia (the book icon) that gives humurous, rather than really informational, data on each celestial body.

Pardon for brushing aside the tumbleweeds of this thread, but wanted to share what I found out about the Get Me To LKO vessel profile. To minimize deviations, I performed the profiles using MechJeb to compare one profile to another) At the most optimal angle for this specific design (~25% profile shape) and starting the turn at 30.5m altitude, the closest I could come to establishing an orbit at full thrust (max TWR) was short by ~64 m/s dV and as a result the booster never raised the Pe above the atmosphere initiating a premature re-entry. By limiting the throttle to 65% all the way up, I was able to get the booster into LKO with ~5 m/s dV left, which when the payload is staged becomes about 40 m/s dV for de-orbiting the booster, which works well because that will occur 10-20 minutes (or another orbit or two) later. As to the TWR question of the OP, while the amount of dV here is actually not so significant, it definitely shows that Kerbin's atmosphere has an influence on efficiency - a relatively simple change of profile in this case decreases the overall cost of the mission at least 10%, in practice even more.

First, the obvious - have you tried to set the "Parking Brake" (the icon near the altimeter, a triangle with an exclamation point) ? Gonna go out on a limb here and guess that you have a lot of reaction wheels on your vessel and you're seeing the result of all of them 'reacting' to the movement of Kerbin (it seems to be a PhysX thing). Among things to try might be turning off the torque of each component that has a reaction wheel. Hope one of those suggestions helps... Good luck!

Thanks for the info link, CBase; hope this link works... https://kerbalx.com/Wobbly_Av8r/Get-Me-To-LKO Give her a rip at max TWR and see if you can find a profile that will achieve LKO. If you can, let me know what profile you used, and if you are unable to, I'll let you know what I found to work. The intent of the design is to enable the booster to achieve LKO so that I can deorbit at the time of my choosing that enables me to get close to KSC for max credit for recovery.

Yes - not sure what the preferred method of making a craft file available here would be, but here is an image - the boosters are intended to lift a 43.789t payload into LKO. I have, indeed, found a narrow set of solutions solely based on launch profile, none of which occur at max possible TWR from liftoff. While there are virtually infinite ways to go about accomplishing a task in KSP, my intent of using this booster set was due to the fact that the Twin-Boar and attached Jumbo 64 tank can be recovered near KSC for > 20,000 kerbucks, which reduces my overall cost. And as it applies to our conversation, it is just fortunate happenstance that the only way I could get this vessel into LKO was a very narrow window of profiles (with 3 m/s dV left in the booster...) [ Edit: I was actually able to eke the left-over fuel to 5 m/s of dV ! ]

While I can appreciate your point, the challenge addressed the same aerodynamic shape on different profiles (as far as I can tell). What I think your challenge would confirm is that certain designs are best blasted into the heavens at the speed of heat, but I've got designs that definitely are more efficient with a 'slower' profile, whether that comes from launching more vertically or throttling down in the lower atmosphere and using the increasing Isp to get a few extra miles per gallon - in fact I discovered that by running out of fuel before establishing orbit and then changing to the slower profile and getting into orbit with fuel to spare!

Well, I did an extended test of a coaxial rotor vessel from the surface of the Explodium Sea up to 25,000 m and after taking pains to make sure both rotors were contributing the same amount of Deploy Angle (and almost an hour and a half of mission time without warp!) had no issues from an aerodynamic point of view. And all this on less than 11 kg of fuel (and using less than 27% torque on each motor), but of course I didn't start by having to fly to Eve or descend to its surface, but it was interesting to - given what I observed - validate the idea that if one were able to get things adequately slowed after achieving an orbit around Eve, the helicopter assisted descent / ascent could hold a lot of promise... I'm going to repeat the experiment with counter-rotating tandem rotors to see if that configuration can replicate a level of success that is similar, but as I said, it takes time because physics warp makes the whole rig unstable so I've had to do it in real time. Not sure what effect is causing your issue, but overall, given all that has been revealed so far, the only additional tips I can offer are to take it slow and easy, placing more emphasis on keeping all rotors producing positive lift more or less equivalently and keep the vertical speed less than 10 m/s?? Maybe it's the vertical speed and its affect on the angle of attack that is creating your issue? My experimental trip began at 5.5 m/s and slowly reduced to 4 m/s at 25,000 m but numbers remained very stable and only changed slowly... Again, Good Luck!

I've never really looked at TWR being "the" factor in deciding to use all engines or just the SRB's to get going off of Kerbin - if you're talking about efficiency, i.e. least amount of fuel used to establish LKO, the decision is influenced by how efficient your LFO engine(s) are vs. the increased amount of drag you will have to overcome by accelerating too quickly in the lower, denser atmosphere. A different way to think about it would be that, say, if there were no atmosphere on Kerbin, it would probably take ~2400 dV (wild stab to illustrate the principle) to establish a 70-75 km orbit, so the atmospheric drag is what causes you to require more dV (on average 3100 - 3400 dV). That atmospheric drag requirement increases if you accelerate too quickly in the denser, lower atmosphere, and most (if not all) LFO engines burn their fuel less efficiently down low as well. Beyond these quantities are some interesting aerodynamics, like the Twin-Boar, whose drag rises quickly up to Mach 1... and then quickly drops (the drag being produced not from 'headwinds' but from the 'suction' of the base of the booster...). Again, the joy of KSP is discovering the strengths and weaknesses of any number of parts and strategies, each somewhat unique in their application, which in turn perform better at various TWR's, not just one ideal value.