arq

Airhogging is not necessary. I've done it with a intake/turbojet ratio of around 2.5. IIRC, my plane had 4 turbojets, 9 or 11 intakes, 2 aerospikes (though LV30's would have been better) and 1 LVN. It gets up to around 25km/1500m/s on jets, then kicks on all the rockets to get up a bit, uses the LVN to finish getting to orbit and circularizing, and really only uses the LVN from there (more than enough power to land on Minmus). Fuel goes further than you'd think with a LVN. Over half the rocket fuel gets burned getting into LKO, and the rest is plenty for a Minmus landing and return (getting back from Minmus is only maybe 300dV).

Because of the Oberth effect, it is likely that there is some regime where multiple LVNs are actually more efficient since a shorter burn spends more time at lower altitudes (you can perikick to get around some of this, but for further planets you spend half the burn on an escape trajectory, and you can't perikick once you hit an escape traj). That said, it's a whole lot of math (numeric simulations are probably easier) to discover that regime precisely. Mostly for the sake of my finite patience, I try to have roughly 1 LVN per 50t of vessel.

I spent awhile learning to put up heavy tankers. A good place to start is putting about 320kL (10 x32 tanks) into LKO. IIRC, this payload is roughly 200t. The biggest one I ever managed to put up in a single launch was 409t, but the strategy is essentially the same. I use onion staging under the payload with stacks of 2-3 x32 tanks over mainsails (fewer in the middle, more on the outside, to maintain TWR as you lose stages). Just put those outward in rings and you can get most anything into orbit. I recommend using Kerbal Engineer Redux or any other ship calculator to work out the TWR/dV stats. Generally you want TWR in the 1.7-2.5 range and a dV of roughly 4600m/s for putting big stuff up. The real challenge is the sparing use of struts to keep a good framerate while still holding together.

Yes, ISP never goes below the atmo rating. On Eve, it will have 220 until it thins below 1 (kerban) atmo.

Also, I find adjusting the pitch of individual lifting surfaces to be risky. Because of all the drag experienced on re-entry (especially from Minmus or other planets), it is very easy to flip or spin the aircraft (though maybe it isn't as bad with FAR, I've only played with it a little). The issue with angled wings is that it may control your CoL when upright, but if you end up upside-down the angling will have the opposite effect, sometimes greatly complicating recovery. Just think carefully about it, and if you have recovery issues then remember that this may be why.

Another thing that can cause spin is not enough struts on outer stages. The thrust of the engines can cause them to twist slightly and cause unstoppable spin. However, if you have cross-strutted as much as you say, that is probably not the issue. Usually if I put one strut at the top of 3 x32 tanks and one at the bottom, going inward and with a mainsail at the bottom that is usually plenty to keep stuff stable, if I add a cross-strut every other ring.

After awhile of messing with SSTO's, I finally made one that could get to Minmus and back. Unfortunately, my aerodynamics were not great on re-entry, so it insisted on flying backwards. After wrestling with it for awhile and giving up the runway, I decided my only option for a landing was to put it down on the tail vertically. But most of my fuel was gone from repeated efforts to land forward. I ran out of fuel 30m up and dropped from there, came down hard on the tail and wrecked half the craft, but the pilot survived. I called it a win and have since gotten much better with designing planes to behave on re-entry.

Bahaha I like it.

Based on the Oberth effect, I would suspect that the most efficient way would be to do a normal ascent profile and just keep burning prograde horizontal near the fringe of the atmo until you reach the desired apo, then raise the peri to match. So, 'no, don't circularize' (though at some point in the transfer it will become roughly circular). Though it is possible that a bi-eliptic transfer *could* be more efficient than the standard Hohmann, depending on the final altitude. If I recall correctly, that is useful if you're changing your orbital radius by more than a factor of ~13, but you'd need to read up on that more thoroughly (though the savings are small at best and prob not worth the extra effort).

Usually to do spot landings I get a low orbit at a high enough inclination to pass over the spot I want, wait for my orbit to be over the target, and then deorbit with a burn that goes slightly past the target (so that the entry burns will put me very close). Of course, a marker could make the process of getting very precise landings more accurate. Also, this works poorly with a thick atmo (ie Kerbin or Eve) because it is difficult to predict the exact drag losses. A marker could be helpful.

I really dislike the current 1,5,10,50,100... timewarps. I would much prefer to set them to 1,3,10,30,100,300,1000... to keep the relative rates between warps more even. I don't know if that's easy to change in some .cfg somewhere or what, but I would love to change this either through a single file or a mod.

To adjust the East/West longitude of polar orbits, simply wait to launch until you are where you want to be. After launch, your ship will stay at that longitude, so if it happens that another one is 45deg behind it at launch, that polar orbit will be 45deg away in orbit too. To change the longitude after launch, make burns in the desired direction (and perpendicular to pro/retrograde) at the north/south pole. However, changing is very expensive so it's easier to get it right the first time.

The 'drag factor' (which is the same for both, yes), gets scaled by the weight of the object. So the large chute, weighing X (3?) times as much, has X times the drag.

I've gotten pretty good at landing SSTOs on a landing gear in a vacuum, because I never remember to put legs on the back.

A Jool window was about to open, so I sent a rocket packed with probes and a small fuel tanker off for there. Though after I got the 2nd ship set up on a transfer orbit (took like 6 periaps kicks to get the dv with the low TWR) I set it to time-accelerate out of Kerbin's SOI only to watch it crater Mun at 3500m/s. Oops. I had to spend an extra 150m/s to add evasive maneuvers to my Jool transfer...

One thing to look out for is that with the SAS changes, it is possible that rotpower will be reduced/removed from capsules/probes, so you may find your old craft very slow or even impossible to maneuver (I, for one, haven't used SAS in ages because it's just a bit useless atm). Even then, I'm thrilled about the new changes. I don't have many major orbital constructions, just lots of individual craft. And I get to keep what I learned in the process of making all of them.

I use onion staging as a simpler alternative to asparagus with only slightly less efficiency. As far as how to keep a high TWR in the later stages? One trick here is to make your outer stages carry more fuel. For example, for a 400t payload I put up I use 2 x32 tanks above my center stack and first ring (of 6). I then use 3 x32 tanks above the other rings. This gives you a lower TWR (I design for roughly 1.7 at the launchpad) earlier but can keep it from falling off as badly as you lose engines. If you were really trying to maximize TWR, you could use even fewer tanks on the inner stages. Also, I sometimes design my innermost ring (around the core) to *not* feed into the center, so that I get to keep all 7 engines for their full burntime, but this means you need to feed the center stack from the 2nd ring. The key to asparagus (or onion) staging is managing TWR. If all your stages start with at least 1.7 TWR and you can get ~4700 delta-v on there, it'll take you to orbit. Well, assuming it holds together...

Any more than 4 intakes *per turbojet* is overkill. Honestly, that is still a lot. I have an SSTO that is capable of Minmus landings and returns and it runs a 9:4 intakes-to-jets ratio. It can easily get to 23km/1500m/s on the jets (and a little more if I were patient enough to slowly back off the throttle). So a ratio anywhere from 2-4 intakes per engine is reasonable for SSTOs. I opt for the lower end for aesthetics. If I were running 15 intakes, it might get up to 27km/1700m/s (now I'm making stuff up, I'd need to do this experimentally), but placing all those intakes ('air hogging') can be a pain and it doesn't massively reduce the delta-v to get to orbit. EDIT: After some more reading, I need to correct my above statement. With airhogging, it is possible to achieve orbital speeds, where you just need a small amount of delta-v to circularize at apoapsis. If you do not intend to airhog (some people consider it exploitative) then 2-4 intakes is fine.

There was some analysis a long while back where it was decided that, based on KSP's drag model, the most efficient (delta-v) ascents are ones that follow terminal velocity all the way to orbit (or as far up as possible, because above 30km terminal velocity starts getting very high very fast), especially for the vertical ascent part before a gravity turn. Terminal velocity means <drag> == <weight>, so in a uniform atmosphere you need TWR == 2. The atmosphere is not uniform (it decays exponentially), so actually you need to accelerate to keep terminal velocity. This means your TWR should be in the low 2's to get up in the smallest delta-v, and should increase to the mid 2's as you get around 15km. Lower TWRs will still get you to orbit, but nominally require slightly more delta-v. I try to keep my TWR at least 1.6 for every stage, except for circularization where 0.7 or sometimes lower can work. Asparagus staging is not a cheap trick. It was not invented in KSP but existed long before (though rarely in practice because of issues with cross-feed). It is also very difficult to avoid with very heavy payloads (in my above example with a 400t payload, you need over 30 mainsails on the *first* stage just to get off the pad at an acceptable TWR - how many stages are you planning on stacking with conventional staging? the VAB is only so tall). Clustering as a cheap trick? Ever looked at the back of the space shuttle? I count 5 engines. In KSP it's just a matter of wanting to get different mixes of thrust and ISP when we only have 10ish engines to choose from and can't custom-design each one. I don't do it because of part count issues and simplicity, but precisely nothing wrong with it.

Yup, you have accurately addressed the advantages of smaller engines. Every tool has its place. As for outboard engines decreasing range - I usually find that this is a result of adding sections with low TWR, as that can make your launch less efficient meaning you burn a lot of extra dV getting to orbit (sometimes more than you added with the extra tanks). Though there are other ways this can happen, too.

Just play around with the cursor and putting it in different spots. It can be tricky to find where they will attach to the tanks below, but there is a place. I just find it on habit now, but IIRC if you place your cursor a bit above one of the lower tanks you'll get the option to stack. Remember struts! The decouplers alone are not enough to hold it together, but you'll figure that out pretty quick either way.

I like mainsails for large vessels because they have over 2x the power of skippers. If you're TWR is ever far below 2 during launch (except for the final bit of circularizing orbit), you're prob better off with more engines, even if they're less efficient. Really, you want your TWR to be in the 2-3 range (higher later in the ascent). For putting up large payloads, mainsails are a must. To put up a 400t payload the whole vessel is roughly 3000t at launch. That is 20 mainsails *just for a TWR of 1*. To get that thrust from skippers would require 45 of them (and the engines would weigh 50% more) . Now since you want a TWR around 1.7 on your first stage, you're looking at more like 34 mainsails. Doing that with skippers (or god forbid anything smaller) would be a partcount nightmare (over double the number of engines, plus the extra stuff to mount them). Both engines have their place. Mainsails have lower ISP, but also higher TWR. So they keep partcount down, especially on your first stage (which is typically half the parts of my full vessel), and have similar efficiency to skippers given the lower weight. My general rule is that if I can get a high enough TWR with just a skipper then use it. If it isn't as high as I want, replace them with mainsails. When it comes to asparagus (actually I use onion) staging with large payloads, mainsails really are the answer. At the end of the day, I use mainsails much more than I use skippers. As you said though, the smaller engines have higher yet ISPs, if you really want to get off on the cheap, you just need to cluster a gazillion aerospikes. Though this only works for small and medium sized vessels because of just how many it requires.

I highly recommend this mod too. I never build something without it any more. I like that it is *just* info (not quite ready to give the game up to autopilots quite yet).

People swear that intakes can kill a launch, but running Kerbal Engineer Redux I check my drag forces with them open and closed. The difference is usually 2-4% of the total drag force, so it's not that significant (especially because drag force starts dropping waaaaaay off around 20km). That step really isn't as important as most people claim, but every little bit helps. Also, you start getting dramatically diminishing returns above 4 intakes/engine, as the air starts becoming exceedingly thin above 25km.

I still believe that this is a CoL/CoM issue. I frequently experience the same thing. You can't use the flip direction as an indicator. It will flip any direction (usually the nearest) to get the CoL behind the CoM. My solution is thus the standard one: your shifting fuel load moves the CoM behind the CoL, you need to move your CoL further back.