herbal space program

1. Yes, you are right. I actually meant dry mode when I said "wet mode". 2. Because the weight and drag of all the wings is offset by the extra lift that allows you fly near your prograde vector, especially up high where the air is thin. Having a really high AoA with all your fuselages will just kill you with drag that does not produce any lift. Hence the pitched-up placement of the wings also, to allow them to have a positive AoA while all the fuselages are pointed prograde. I have built planes that way since at least 1.2 or so. Just keep adding wings to your own design and see what happens! 3. A fair point, although Swivels actually have a slightly better vacuum ISP than Reliants (320 v. 310). This small difference may be mostly offset by the added weight, but the gimbals do come in handy so long as you have enough TWR. Could go either way for what I have, but for anything larger, I agree the better TWR of the Reliants will become critical. In fact, I noted tardily that I only had room for 4 passengers when 5-6 were required, so I may try them on a version with an extra crew cabin. 4. Drag is always a key consideration whenever you are trying to fly something into LKO at a low TWR. The fairings only weigh like 0.2 tons and reduce the overall drag of the engines by more than half, so they are often worth it. The Swivels in particular had awful drag, so I covered them first, but then I saw better performance when I covered the Panthers also. As to clipping stuff, I think that will only cheat the drag model if you then put all the clipped-together parts inside a fairing. Not really Cricket in my book, but YMMV. Anyway, I look forward to seeing what you come up with! ...As an update, When I switched to the Reliants I was indeed able to get better overall performance, getting roughly the same dV on orbit as before, despite an added passenger module for a total capacity of 6. The gimbals were definitely missed though!

Here it is in the SPH. Total mass is 56.8t, vacuum dV of the rocket stages is 2879 m/s. It has two MK1 passenger modules, at the front of the stacks left and right of the cockpit, and I'm pretty sure it doesn't have any parts you haven't unlocked yet. It has 3 Panther and 2 Swivel engines, each with a backwards-facing fairing in front of it to reduce otherwise severe back-end drag. The substantial wings are pitched up a couple of degrees relative to the fuselages, to generate lift even when the fuselages have an AoA of zero. I also have 5 intakes for 3 engines, which is a good idea if you're going to go as high as you can on them. Since you presumably don't have the Z-1000 battery yet, I put a couple of draggy z-400 ones in the service bay in the center stack. If I were building this in Sandbox, I'd have definitely used wet wings to lower overall drag even more, but I'm assuming you don't have those yet. In terms of flight profile, I started off at a low rate of climb and built speed low in the atmosphere, in dry mode. With this plane, I was never quite able to break the sound barrier in dry mode, but I could get very close to Mach 1. Turning on the afterburners would then push it across fairly quickly, after which I could then switch back to dry mode and only slowly lose velocity while climbing further at about 10 degrees of pitch. Although I never really got above Mach 2.5, I found that I was able to maintain that speed almost all the way to 20 km on the Panthers alone. I would start to lose speed at around 18.5 km, at which point I would pitch up to 20 degrees and fire up the Swivels. The Panthers would typically flame out at ~23 km, and the rest of the ride to orbit was pretty straightforward: I always ended up with quite a bit of extra LF in the tank as well, so there is plenty left to land under power. Rather too much in fact, which represents a point of potential improvement. And although I think you have plenty of dV to orbit the Mun with this craft, I'm sure it would tolerate a couple more small tanks to add another 100-200 m/s. I'm pretty sure you could land it on Minmus then as well!

So I came up with one this evening that makes LKO with around 1,100 m/s. Do you want to see it?

If nukes are allowed then I'm absolutely sure it's possible. One thing I'm noticing about your design is it has very little wing area for its mass, which makes flying up high much harder due to the drag incurred by the high AoA you need. Also, are your wings tilted slightly up relative to your fuselage? That angle of incidence will help you fly witha lower overall AoA and therefore go faster. Wet wings are also really helpful in increasing efficiency, since you get the fuel they hold for free in terms of drag, but I guess you haven't reached that tech level yet. Also I concur with @Cavscout74 that Mk1 is much more drag-efficient than Mk2, so definitely switch to that. I'm not sure if it's allowed in career mode, but you can use f12 to look at your aero characteristics and also alt-F12 to enable displaying part-specific drag in the PAW, which can really help in rooting out drag issues.

This seems doable to me, but unfortunately your image link appears to be broken. What rocket engines besides the Reliant do you currently have available? Do you have everything up through the 160 science tier? Since the Panther should easily be able to get you above 20km, I would think the Terrier or Poodle engine would actually be your best bet for the rocket part since they have much better vacuum ISP than the Reliant. I may give this a try later myself...

Your problem is that you did such a good job on this challenge yourself that nobody else wants to try to beat you!

I took a look at your SSTO, and while it incorporates a number of really good ideas like mounting your props in service bays and putting a bunch of stuff behind fairings, to me the degree of part clipping involved is disqualifying , because you're basically just cheating the drag model. For the most part, challenge issuers for this sort of thing (including me) allow part clipping only if it does not put solid, massive parts substantially inside each other. So for example if you want to mount multiple engines with large bells into less space than they really fit, moderately clipping just the bells into each other might be considered OK, but not mashing all the engine bodies together, as you surely must have done with all those Nervs. When I went to the SPH to try to imitate what you had,I found that while you apparently used 2.5m fairings to house your tanks, etc., not even 5m fairings of that shape would actually fit all that stuff inside without a lot of clipping. To me that's pretty egregious, especially if we're talking about Mk1 LF fuselages, which already have quite a high mass/drag ratio. So although I'm definitely impressed, I would not consider that craft as really demonstrating that a Jool SSTO is possible without doing something that's generally considered cheating.

The Wolfhound from MH has an ISP of 380, so that would technically be high enough, although its TWR is nothing to write home about. My prior statement about Nervs however was based on an inaccurate idea of how strong Jool's gravity field is. They would definitely have enough TWR to be useful at only 7.85 m/s2 of downward acceleration. And as I just went there with my plane using HyperEdit and saw that a 200 km circular orbit is like 5.6 km/s, I don't doubt that it actually takes close to 8 km/s of dV to make orbit. Those props are great for lifting you out of the worst of the soup, but they don't get you going very fast.

I was going to protest that must be impossible, but then I looked at the Wiki for Jool and saw that its "surface" gravity is only 7.85 m/s2, like Laythe's, in spite of having an orbital velocity of >3 km/s. I'll have to give it a try with my current plane, as I think it'll probably be about the same as Kerbin to get off of between the higher OV and the lower gravity. Eve is a different movie though. It has more than twice that surface gravity at 16.7 m/s2, which means you need a whole lot of TWR to avoid plunging back into the soup. In that gravity, the Nerv engines alone only have a TWR of 1.2, so I never found them so helpful in making orbit. I still think it's totally doable though!

The nukes are great on Kerbin or Duna, but I've found that in Eve's high gravity TWR is so critical they're generally not that helpful in making orbit. Since this ship makes Kerbin orbit with >2km/sec, I'll still have >1km/sec left if I swap them for aerospikes and replace the extra weight with fuel. Bare Wolfhounds might represent a good compromise in that regard as well, which I have not yet investigated. Also, out of curiosity, how do you define SSTO-ing on Jool?

It certainly looks like it was slapped together by my drunken chimpanzee avatar if that's what you mean! I actually started over completely 5 times in this process. Each time I told myself I'll make it look good this time, but then each time, after like 30 test flights and trips back to the SPH, I ended up in about the same dorky place appearance-wise. Once I really get it flying the way I want it to, I'll probably set about remedying the fact that it looks like a flying exploded diagram. There's just a lot to consider, and having all the engines assymetrical makes moving some things around a real pain in the end that should not point towards space.

Good post! It's great to see people investigating the awesome potential of the BG rotor parts to make getting off Eve something other than a booster-spamming contest. For my part, I'm working on a prop-powered Eve sea-level SSTO: It makes Kerbin orbit with >2km/s using nukes: And flies pretty well on Duna too: I'll need to create a non-nuke version for Eve, but with that much dV on Kerbin orbit, I'm pretty optimistic it will work!

I expect at some point the physics engine will break down and crash the program, but other than that I doubt anything particularly interesting will happen.

Besides, even if it's metastable enough to be containable with something lighter than Jool, how are you going to get to it? I think Helium-3 fits the bill a lot better as a difficult-to-get resource that enables a super-efficient propulsion system. The Kerbals actually have fingers! Also, I thought it was said there'd be no BG parts, but those stations had rotating segments.

I can't believe I'm the first person who voted for the generic game pad controller. I can joystick so much more accurately with my thumb than I can with my wrist, and the available axes, buttons, and HAT switch fit all the things I need to do continually while flying so well. I use the keyboard for everything that won't fit on the controller and the mouse to select in all the map modes. I'm left-handed, so for me the left joystick is yaw/pitch, and the the right is roll/translate U/d. Translate F/B, L/R is the HAT switch. Throttle up/down is the left trigger buttons, and toggle SAS/RCS is the right ones. I use the top buttons for staging, cut throttle, full throttle, brakes, and toggle gear. I find I can fly planes that way with only a handful of keystrokes to invoke action groups. I can hardly imagine playing any other way, TBH.

Yes indeed I meant that, thanks for digging it up! As to the drag factor, I think I can say from experience that whatever drag you might incur by tiling your craft with OX-stat solar panels, it will be far outweighed by the drag from the propellers themselves. On the plus side, something not so far away from my current design was able to reach 23 km on Eve pretty easily. Not sure what the exact pressure is at that altitude, but it's definitely a whole lot less than it is at 7km. And there's not only the drag to contend with. There's the awful engine ISP you get at >ASL pressures. It makes getting off the surface such a maddening problem. Anyway, I'm not sure if a plane is really the way to go. I have a feeling that just helicoptering a regular rocket to 20+ km will end up working the best, but it would be so cool if it could be done as a plane, so I'm trying that first...

It has been done only once in pure Stock AFAIK, with a gigantic, crazy ship that took off from the highest point, like 7km. What I'm hoping to do is use the propellers from the Breaking Ground expansion to get my plane to ~25 km without using any fuel, which might just make it possible from ASL with a more normal-looking plane. But it's going to be tough, as those propellers are both really heavy and really draggy and hard to manage once you enter the rocket phase of the ascent. It took me three solid days to produce a Kerbin SSTO with electric propellers and no air-breathing engines, and an Eve one will be quite a bit harder.

After a a ridiculous amount of difficulty, I made my first solar prop-powered, non air-breathing SSTO space plane last night. Using 6 8-blade ducted fan props, 2 aerospikes and a Nerv, it made orbit with a whopping 295 m/s dV left in the tank, enough to go...nowhere. That's a far cry from the ~5km/s I was typically getting with Rapiers and Nervs, but it's a start! The idea of course was to make an Eve SSTO, so I've got a long way to go....

No, that part was just a matter of personal preference for me, but it was part of my procedure so I included it. I'm using the torque limiter as my main throttle axis and have the blade pitch mapped to translate up/down, both with incremental rather than live axis control (I'm using a Nintendo-style game controller). I set it that way so I'd have some forward thrust to start with and also so that I'd have enough control authority to get my blades nearly edge-on to the airflow to reduce drag while boosting out of the atmosphere. I found that when flying as fast and high as possible, you have to keep that pitch angle on just the right value or you suddenly aren't flying anymore. The only way I was able to get the best performance was to have the Alt-f12 aero markers on and use those to guide me. Also, as you get higher up you sometimes need to reduce blade pitch (i.e. lower "throttle") to go faster, because there's a complex interaction of the motor RPM, air density, and airspeed. It feels more like a trim adjustment than a throttle axis to me, that gets more and more critical the closer to the edge of the envelope you get. Since what I'm ultimately trying to do is make an Eve SSTO with a prop-driven initial ascent stage, I need to figure out how to get every last bit of height and speed out of those props while hauling a heavy load, so that trumps all other considerations. For that reason, I have props that only go like 120 RPM at max throttle on the ground, and only reach their 460 limit at ~13 km. I think that makes stuff more complicated for me.

Here's what I did: I started by placing two pairs of mounting points on the wings using mirror symmetry, then adjusted their heights/angles using the rotate/displace tools in absolute mode with angle snap. I then placed one engine, not using symmetry, on one of the left-side mounting points, set it to "octo" for blade placement nodes, then put the blades on the hub using 8-fold radial symmetry and angle snap. I set the rotor and blades both to "clockwise" and set the Deploy settings to "normal" and "extended", finally setting the Deploy Angle to 0 rather than 60. I then used the rotate tool, in Local mode with angle snap, to set the blade pitch to one click clockwise of flat. After doing that, I pulled that motor off, set it aside, and hit the undo key. I then put the removed motor on the opposite node, set it and the blade variant to "counterclockwise", and changed the Deploy setting to "inverted". With a regular propeller, that would be all you'd need to do, but somehow with the turbofan blades they snap to the wrong pitch when you select the CCW variant. So I used my rotate tool again on those blades, using local mode with angle snap, to rotate them to the mirror-image starting pitch of the ones on the other side. Once I had actually done that correctly for both of my CCW engines, everything worked right. Make sense? And yes, it was a royal pain in the exhaust nozzle figuring all that out!

I don't have a link to the craft file, but here's a pic from the SPH where you can see them all facing the same way: BTW, I'll add here that I tried this with and without those ridiculously heavy shrouds and I noted no obvious difference in performance or how all the aero indicators looked.

What I'm saying is you have to do do that manually for the ducted blades, using the rotation tool, but not for the other ones, so there is something wrong about how the two variants are configured for that series of parts. You can actually get thrust from a ducted blade even if it's mounted backwards, but that's another matter. Anyway, here's a pic of my ducted fan plane with two pairs of counter-rotating propellers. As you can see the thrust vectors look more or less the same for all 4 of them.

What I noticed is that for regular propellers, if you set the first one up clockwise and then clone it and just toggle everything to be backwards, it works fine, but it doesn't for the turbofan propellers. IOW, when you set the blade variant to CCW for a regular propeller blade, it will snap to a mirror image of the pitch of the CW version, but when you do that to a turbofan blade, it ends up at the wrong pitch. I had to adjust them all manually to get it right, but then they worked fine.

After burning the better part of my weekend, I'm getting the hang of it so to speak. Flying propeller aircraft is tricky! When I went to bed last night, I had a plane that fell just shy of making LKO in a single stage using only electric props and aerospikes. The rocket stage had a vacuum dV of ~2.5km/sec with all the propellers attached, which is less than I would need to get so close to making orbit from the ground, but without the props I think I would have had enough dV to do it. The best I've been able to do so far hauling that rocket stage with the ducted fan blades is around 180 m/s at 13km with the prograde marker like 20 degrees above the horizon. I can get higher than that, but only at the cost of a lot of speed, and from that altitude the drag of the propellers during the rocket burn is pretty cumbersome, even if I do my best to manage it with the blade pitch control. So I feel like unlike jet engines, propeller stages really don't help you making orbit on Kerbin, but what is cool about them is that after re-entry, you can fly essentially forever if you've got enough batteries and panels. Of course Eve is another matter, since there are so many bad effects from the thick atmo, but from what I've already done I can see it will be challenging!

My $0.02 is that orbital rendezvous seems like a great tool to teach some counter-intuitive features of Newtonian mechanics/basic calculus. You have to go lower to go faster, higher to go slower, and figure out how to work in 4 dimensions. Depends on the level of the class of course.