[Stock 0.16] Rockets, Jets and a Spaceplane

[Tarmenius]

*WARNING: Image-heavy thread*

Greetings ladies and gentlemen. Thank you for stopping by my humble showcase! I have nine designs to share with you today, but don\'t let that number intimidate you. Each one is tailored to a different purpose and style of piloting. Four rockets, four aircraft and one SSTO spaceplane provide a wide array of options to meet almost any mission profile. The rockets have been designed with minimal debris in mind while retaining the capability to reach either of Kerbin\'s moons. Two are single-Kerbal craft and two utilize the new three-Kerbal Command Pod. The four aircraft are very stable in flight, using advanced placement of both lift and control surfaces. Apply a little trim to render the included Avionics Packages unnecessary. They also include a fairly generous fuel supply for extended loitering or medium-range travel. The single SSTO spaceplane is also very stable during atmospheric flight, and surprised even me with its capabilities which I will go into in due time.

And now that the 'fake company' segment is finished, allow me to present to you my various designs:

The Rockets

All but one of the following rockets feature an asparagus-stalk design. This allows a greater potential payload without a terribly massive set of lifting stages. The first on my list will demonstrate how it is used and what you can expect during the ascent.

Demeter Mk16

This single-Kerbal rocket is a re-packaged design from previous versions. It\'s very reliable and is often my go-to rocket for basic Munar or Minmus(ian?) excursions. Here it in in the VAB:

Its simplicity affords it great flexibility, but the lack of RCS may be intimidating to newer pilots.

In this next screenshot taken soon after launch, you can see that all seven LFEs are active. This is what gives the asparagus-stalk design it\'s kick. For this rocket, full throttle is not needed as atmospheric drag would prevent much increase in acceleration.

Note the throttle setting. Even here, I am pushing against the air a little too hard and am wasting some fuel. Fortunately there is plenty to spare.

With the correct fuel line setup, all seven LFEs drain fuel from just two stacks, allowing empty weight to be jettisoned sooner. Here, you may want to increase throttle just a little to make up for the loss of two LFE\'s, but it isn\'t required.

This stage can be tricky as the not-perfectly-symmetrical fuel stacks will give the rocket a tendency to spin when ASAS is off. With a little practice, gravity turns aren\'t difficult as the natural spin isn\'t very strong.

Now that the rocket has jettisoned the two asymmetrical stacks, it no longer wants to spin and focus can now be put fully on achieving proper orbit. Good thing, too because this stage will take you through at least most of your burn to circularize. Just before staging, I tend to set the throttle to 100%.

They don\'t necessarily have to be horizontal, but it feels like the right thing to do.

If you\'ve made an efficient ascent, you may want to jettison these stacks with fuel still in them to avoid space junk. You\'ll want to do this when your Pe is at or below 23,000m as anything in orbit above that will remain when put 'on rails.'

With orbit achieved and nearly all of the central stack\'s fuel yet to be burned, either moon is well within reach.

Please note that the tendency to spin during the 4th Stage is a common trait to all rockets that use the asparagus-stalk setup, as far as my experience has shown. If you know of a way to prevent the need for active spin control in this design (i.e. manually counter-spinning with Q or E), I would be very interested to hear it.

Antares Mk16

This single-Kerbal rocket is also a carryover from previous versions (hence the 'Mk16' on both), however this one predates the Demeter. This was my rocket of choice when I was still new and just learning about efficiency. It has a larger fuel margin and plenty of RCS for orbital maneuvers and steady Mun or Minmus landings, making it a very forgiving craft. Perfect for those who are also still learning or who want to not worry much about their fuel budgets. Ascent to orbit is almost identical to the Demeter, with more throttle being needed here due to the larger overall design.

As you can see from the following image, the Antares Mk16 will also acieve orbit with almost the entire center stack of fuel still to burn.

I was really hoping to get a screenshot of the lander sitting on the Mun, but for some reason the RCS tanks get disconnected anytime I come out of warp (with or without struts). Oh well, I guess you\'ll just have to try it out for yourself [uPDATE] I have made three design changes for those who have the same problem with RCS tanks disconnecting, or for those who want a more powerful Lander engine.

Antares Mk16b

I removed the Removed the four RCS tanks and replaced them with only two directly under the ASAS unit. I swithced the LV-909 for the LV-T45 and replaced the small landing legs with the larger ones to account for the added clearance needed. This has resulted in an even more forgiving Lander that still has a comfortable fuel margin.

Here you can more clearly see the changes made

With orbit achieved, there is plenty of fuel for the TMI burn

And even some left over for the capture burn as well.

On the surface, there is more than enough fuel to get back home; and possibly seeing another nearby landing site before you leave.

Hermod

The first three-Kerbal rocket I want to share is a cross between the old and the new. It features an asparagus-stalk setup similar to that of the Antares Mk16, using the old fuel tanks and LFEs but with the new SRBs to help with the initial liftoff. The lander stage is built with the new parts and designed with the simplicity of the Demeter Mk16.

While it will get into orbit with fuel remaining in the central stack, it is not enough to complete a Trans-Munar Injection. Even so, the lander itself can make up the difference. The following photo was taken using a prior design version whose only difference is the large stack decoupler. I had since learned that it was not needed and updated the craft.

During testing of the decoupler-less design, I was able to show that not only

would the parachute be sufficient to support the whole lander, but it was also capable of a fullt powered landing. Observe:

Note the descent rate of 15.4 m/s. Well within tolerances for those landing legs.

Taking back off shows that there is plenty of thrust to perform a fully-powered landing on Kerbin.

Indomitable

This was my first successful rocket design of 0.16 with the goal of reaching the Mun. It\'s got a very comfortable fuel margin and plenty of RCS. It shares the same design philosophy with the Antares Mk16, in that the craft is very forgiving and will get anywhere around Kerbin one may wish to go.

You\'ll probably notice the abundance of SAS and parachutes. Well for one, I think the unnecessary parachutes look cool Of course, I didn\'t know they were unnecessary at the time. I have since learned better. The SAS, however, may or may not be needed. For me, any ship using the large fuel tanks will rotate end-over-end uncontrollably once in orbit. And now you know the real reason why the Hermod uses the old tanks Fortunately, the uncontrollable rotation didn\'t kick in on the Indomitable until after the TMI burn, allowing this:

My first Munar EVA

If you don\'t have that problem with large tanks and want something sturdy, forgiving and capable, you may want to consider this one.

The Spaceplane

Bridging the gap between aircraft and rocket, the spaceplane can be an illusive prize. I have only had one other successful design, but it did not survive the balance changes of 0.16 and so could not be carried over. While unfortunate, it provided me with the challenge of coming up with a new design. A few of the aircraft in the next section were products of that challenge, so I\'d say it worked out well enough.

Gannet

While it may not be the prettiest plane in the hangar, this little jewel is able to get a three-Kerbal crew into space on a single stage. And she\'s incredibly stable during atmospheric flight, not really needing any ASAS at all if a little trim is applied.

It\'s dual-aerospike rocket engines provide more than enough thrust for the craft, so even during the ascent phase I keep the throttle around 60%. Standard spaceplane ascent for me is to hold a pitch-up of 60^o until around 40,000m where I begin to slowly pitch toward the horizon. When I meet with the prograde marker, I follow it until my AP is where I want it. Out of the atmosphere, the engines tend to give the craft a nose-down attitude so be sure to keep the Avionics Package active and pitch up a little while performing any burns.

You may be wondering how much fuel is left after establishing orbit. Well, there is plenty. Enough even for this:

Passing the Mun on a free-return trajectory, you can see there is quite a bit of fuel left. Perhaps even enough to land on the Mun? I haven\'t tried. Yet.

Returning to Kerbin,

I altered my free-return into an orbit so that I could land back at KSC. I even overshot a bit and the craft\'s stability in the atmosphere made turning around very easy.

This post is looking to be rather larger than I thought. I will place the aircraft in another one.

[Tarmenius]

The Aircraft

The first three aircraft in this showcase came about as a result of my search for a reliable SSTO spaceplane. The fourth was a dedicated aircraft from the start. Each one is very stable in flight, and while not quite as nimble as smaller designs, they are still able to be maneuvered with ease.

Merlin

This aircraft was the starting point for my development of the Gannet SSTO, and you can probably see the resemblance in fuselage and wing shape. I use this craft to test out new crew members\' bravery in high-altitude dives, spins and climbs. Only once did I lose control of the craft while putting the crew to the test. It came pretty close to a textbook 'flat spin,' but with the craft\'s stability and well-timed activation of the Avionics Package, it recovered smoothly. As with real aircraft, care must be taken during takeoff and landing to ensure the engine does not collide with the runway. Fortunately, there is plenty of lift to make this a simple matter.

Condor

Primarily an attempt to carryover a previous design, I was also aiming to make it into an SSTO spaceplane. Unfortunately, it was terribly unbalanced in space, resulting in end-over-end flips under thrust. After several failed design adaptations, I decided to scrub the SSTO project and focus on atmospheric flight. What I ended up with is a very stable long-range 'transport.' As you\'d expect, the turn rate is low but still reasonable. It performs very much as you\'d imagine a craft of this type would. Takeoff should be handled with some care to avoid scraping the rear fuselage on the runway, but the craft is responsive, so you shouldn\'t have any issues. Landing is equally easy, even under a full fuel load.

Viper X2

I badly wanted to make this an SSTO spaceplane. I still hold hope that I\'ll find a way to do it (thus retaining the experimental designator 'X2'), but for now the Viper is Kerbin-bound. And while it cannot reach space, it performs well as a high-altitude, supersonic 'interceptor'. It is my first successful design of a non-conventional aircraft and it holds a special place in my mind for its asthetics and potential. I hope you will like it almost as much as I do.

As with all my other aircraft, the Viper is very stable during flight. I prefer to fly it without the Avionics Package active except during landing when I use it to help keep the wings level while I line up with the runway. Again, care during takeoff must be observed to avoid losing the engine, but once in the air the Viper loves to climb.

This next screenshot I\'ve titled 'Aspiration' as a tribute to the lofty dreams this craft inspires:

Kestrel

As stated before, this last aircraft was designed from the ground up for atmospheric flight. The unique shape of its wings inspired the name and I\'m sure you\'ll agree that it fits.

The Kestrel is just as stable as the other aircraft, and while it can\'t roll as fast as the Merlin, it has a smaller turn radius. It\'s very responsive and quite comfortable at low altitudes. Landing provides the only area requiring extra attention. With no thrust and a full fuel load, the glide path can be a little steeper than you might expect and there can be some difficulty in keeping the nose above the horizon. Just use minimal thrust and you should be fine. Once you\'ve touched down, apply brakes gradually as you may lose the nosecone otherwise.

Don\'t let the prograde indicator fool you, I had just started pulling up when I took this shot

The Kestrel flies almost exactly where you point it when at full throttle.

And that\'s my showcase. Hopefully you\'ll enjoy flying these craft as much as I\'ve enjoyed making them. If you have suggestions for improvement, I\'ll gladly hear them. I\'ll also answer any questions you may have about the designs or how to incorporate them into your own aircraft, rocket or spaceplane. General praise is also welcome. But not criticism! Just kidding, criticism is welcome too, as long as it\'s constructive. And if you\'ve read all this, you have my humble thanks.

Happy Launching, Flying and Crashing!

-Tarmenius

[Tim_Barrett]

I think the Gannet would fly better with some vertical stabilization, but other than that everything else seems pretty good! Nice work.

[Tarmenius]

Thank you for saying so. Originally, the Gannet had a V-tail like the Merlin, but its current configuration was made when I replaced it with the large delta wings. I found they looked too large when placed at a higher angle, so I put them closer to horizontal. It doesn\'t have an issue with roll stability, and can even hold a 45^o bank without the Avionics, though the natural nose-up tendency from the engines can cause issues during barrel-rolls. Plus, they kinda look like the tail section of the YF-23. 8)

[Guard13007]

I like the Viper X2, and I really love the Kestrel, especially with its name.

I am gonna try making something similar to the Viper that can get into orbit, but we shall see how far I get...

[Dizzle]

I seem to be using the Hermod incorrectly. I\'m using the lander to complete the orbit, and it\'s all gone before I even get my apoapsis near the Mun.

[Tim_Barrett]

Thank you for saying so. Originally, the Gannet had a V-tail like the Merlin, but its current configuration was made when I replaced it with the large delta wings. I found they looked too large when placed at a higher angle, so I put them closer to horizontal. It doesn\'t have an issue with roll stability, and can even hold a 45^o bank without the Avionics, though the natural nose-up tendency from the engines can cause issues during barrel-rolls. Plus, they kinda look like the tail section of the YF-23. 8)

Well yeah if you are going fast the entire time (mainly because it\'s a spaceplane) then it wont be an issue. But don\'t think gliding will work at a slower speed, otherwise you will just start 'sliding' to one side and end in disaster.

But it makes sense now. Looks good without it anyway.

[Tarmenius]

...it\'s all gone before I even get my apoapsis near the Mun.

How much fuel do you have in the central stack before beginning the TMI? I\'ll do some trials with it to see how much the Lander can handle by itself from Kerbin orbit. Perhaps the fuel margin isn\'t as large as I would have hoped. If that\'s the case, then getting to the Mun successfully will depend on how efficiently you break through Kerbin\'s atmosphere and I\'ll want to design a more accessible version.

But don\'t think gliding will work at a slower speed

According to the test flights, it holds steady even when completely empty, although I will admit it does yaw a little during low-speed turns. Fortunately, it tends to yaw in the direction of the turn, so it\'s a good thing. I don\'t want to sound like I\'m dismissing your input though and if others do find issues controlling it, I will be more than happy to update the craft

[Dizzle]

I\'ve seen people use much smaller craft than the ones I usually build, so the error might be in my procedure rather than your design. Specifically, I\'m burning straight up until my apoapsis is around 150km, then burn towards 90 until I have a 50km periapsis. Then I wait until I\'m near the PE, and just keep increasing my AP until I have a Mun encounter. It usually works, but it\'s not the method I\'ve heard most people use (waiting for the Mun rise), and I\'m not sure if that\'s more efficient.

[Tarmenius]

I see. If I\'m understanding your process right, do you often end with escape trajectories that pass close to the Mun? If so, then I\'d have to say that process is very costly on fuel. Not that it\'s wrong of course, as long as you carry enough fuel for it You might have an easier time getting less mass into orbit if you have a more efficient flight plan in mind, but that\'s only a suggestion.

Also, I tested the landers range by itself from Kerbin orbit and it will get to the Mun and land, but only just barely. Here are the details:

Just after achieving orbit. I was a bit sloppy with my ascent, so I had less fuel than I would normally like.

Fortunately, this mission wasn\'t going to need that fuel anyway.

This is the transfer orbit I used to get to the Mun

And this shot shows how much fuel I had left afterward.

It was nerve-wracking and I wasn\'t sure I\'d be able to get down safely, but I pulled it off.

[wildkittyv1]

I\'ve seen people use much smaller craft than the ones I usually build, so the error might be in my procedure rather than your design. Specifically, I\'m burning straight up until my apoapsis is around 150km, then burn towards 90 until I have a 50km periapsis. Then I wait until I\'m near the PE, and just keep increasing my AP until I have a Mun encounter. It usually works, but it\'s not the method I\'ve heard most people use (waiting for the Mun rise), and I\'m not sure if that\'s more efficient.

I used to do something similar when I first started trying for Munar encounters, but it is indeed very fuel inefficient. Mun rise is a very good point to do a burn, and you want to do it closer to Kerbin than that far away. There is also another way to measure both Munar and Minmussian trajectories I\'ll explain briefly below. As for where you want to be when you burn, it\'s a lot closer. You only need your initial AP to be around 75k (just to escape the atmosphere entirely) and you don\'t want to burn straight up the whole time. I don\'t have it perfect, but I start angling at about 10k (only maybe 5-10 degrees just to keep me pointed in the right direction), which is normally after my SRB\'s have just finished. Then after about 30k I\'ll angle at about 45 degrees and hold that until my AP gets to around 75k. About 10 seconds before I hit my AP, I\'ll angle to about 10 degrees off 90 (10 degrees off the horizon towards spaces) and burn into the AP so it\'s always ahead of me; keeping the AP a few seconds in front of you will prevent you from fighting gravity as you won\'t be losing altitude.

Keeping your initial orbit lower also allows you to gravity turn more effectively. At about 75k you can easily keep any craft over 2000m/s and it costs much less fuel to accelerate into your Munar burn than if your orbit was further. You say you\'re dipping to around 50k at your PE - this is a bad idea. It\'s a bad idea because below 70k you\'re back in the atmosphere and it\'s going to slow you down and you\'re fighting gravity at some point (even if it doesn\'t de-orbit you, it is slowing you down), which is wasting fuel.

It might not be the best way, but it\'s a good way to stay close to Kerbin and use its gravity as a slingshot, and staying just above 70k gives you the most use of its gravity without dipping back into the atmosphere, which is basically like diving into a body of water.

As for measuring your burn, both the Mun and Minmus will travel about 60 degrees around their orbital circumference in the time it takes you to get there from a ~75k Kerbin orbit. For the Mun, it works out that that\'s pretty much exactly when it rises, but it\'s hard to use that as a gauge for Minmus because you can\'t see it. Basically, go onto the orbital map and rotate it so the target is directly to the right of Kerbin (aim top down). Eyeball out a 60 degree advance (2/3 of the way before it would be 'above' Kerbin - at the top of the map) and draw a line from that spot so it\'s tangent with Kerbin\'s surface (not tangent with your orbit!). Continue the tangent line past the planet and draw it through your orbit. Wherever that line passes your orbit, that\'s your burn mark. I can draw up an image if you want.

Sorry if the last bit sounds convoluted, but it works reliably.

[Dizzle]

Wow, that does sound kind of complicated, especially for Minmus (I\'ve only been there once by pure luck, and then I just orbited a few times and came back). Still, I\'ll definitely be trying your advice for the Mun transfer, seems like it\'d be easy enough to do.

[Guard13007]

I used to do something similar when I first started trying for Munar encounters, but it is indeed very fuel inefficient. Mun rise is a very good point to do a burn, and you want to do it closer to Kerbin than that far away. There is also another way to measure both Munar and Minmussian trajectories I\'ll explain briefly below. As for where you want to be when you burn, it\'s a lot closer. You only need your initial AP to be around 75k (just to escape the atmosphere entirely) and you don\'t want to burn straight up the whole time. I don\'t have it perfect, but I start angling at about 10k (only maybe 5-10 degrees just to keep me pointed in the right direction), which is normally after my SRB\'s have just finished. Then after about 30k I\'ll angle at about 45 degrees and hold that until my AP gets to around 75k. About 10 seconds before I hit my AP, I\'ll angle to about 10 degrees off 90 (10 degrees off the horizon towards spaces) and burn into the AP so it\'s always ahead of me; keeping the AP a few seconds in front of you will prevent you from fighting gravity as you won\'t be losing altitude.

Keeping your initial orbit lower also allows you to gravity turn more effectively. At about 75k you can easily keep any craft over 2000m/s and it costs much less fuel to accelerate into your Munar burn than if your orbit was further. You say you\'re dipping to around 50k at your PE - this is a bad idea. It\'s a bad idea because below 70k you\'re back in the atmosphere and it\'s going to slow you down and you\'re fighting gravity at some point (even if it doesn\'t de-orbit you, it is slowing you down), which is wasting fuel.

It might not be the best way, but it\'s a good way to stay close to Kerbin and use its gravity as a slingshot, and staying just above 70k gives you the most use of its gravity without dipping back into the atmosphere, which is basically like diving into a body of water.

As for measuring your burn, both the Mun and Minmus will travel about 60 degrees around their orbital circumference in the time it takes you to get there from a ~75k Kerbin orbit. For the Mun, it works out that that\'s pretty much exactly when it rises, but it\'s hard to use that as a gauge for Minmus because you can\'t see it. Basically, go onto the orbital map and rotate it so the target is directly to the right of Kerbin (aim top down). Eyeball out a 60 degree advance (2/3 of the way before it would be 'above' Kerbin - at the top of the map) and draw a line from that spot so it\'s tangent with Kerbin\'s surface (not tangent with your orbit!). Continue the tangent line past the planet and draw it through your orbit. Wherever that line passes your orbit, that\'s your burn mark. I can draw up an image if you want.

Sorry if the last bit sounds convoluted, but it works reliably.

If I\'d slow down and think about it more, I think the last part would make more sense to me (I tend to be good at spacial things *shrugs*) but I would like the picture, at least to confirm when I think I\'ve got what you meant figured out.

[Tarmenius]

wildkittyv1, your ascent profile is a pretty good general guideline, and fairly close to the one I tend to use myself. And I definitely agree that starting your TMI burn from a lower orbit is more efficient, thanks to the Oberth Effect.

I would like to add that Minmus-rise is just as effective if you learn to spot the brighter-than-normal 'star' as it comes into view. It helps to use the Map View by adjusting the camera angle so that your ship\'s icon is over Minmus\' icon just before they both reach the horizon. This way, when you leave the Map View, you\'ll know exactly where to look for it to rise. I still do it that way.

And Dizzle, I\'m sure you\'ll be able to get there. Even if it does take a little practice (it did for everyone else, too).

[Whaliin]

When i saw the condor, OHH GOD, IT LOOKS SO FREAKING AMAZING MAN!

[wildkittyv1]

If I\'d slow down and think about it more, I think the last part would make more sense to me (I tend to be good at spacial things *shrugs*) but I would like the picture, at least to confirm when I think I\'ve got what you meant figured out.

EDIT!

I removed this image because I just went in and did a launch and realized I made the image backwards. After I finish this mission I will redo the image correctly and reedit it back into this post. I apologize if anyone used it as a reference and it didn\'t work. What you want to do is launch when the tangent is 30 degrees off the parallel I showed in the image. This gives the orbiting body 60 degrees left to travel which is what you\'re aiming for. In the image, I had you burning at a point where the body would only have traveled 60 out of the 90 degrees, leaving you 30 degrees ahead of it.

Sorry if I messed you up, but it does work and is reliable, I just wasn\'t thinking when I composed it.

---

Here\'s a little image I just drew up quickly.

!!NOTE!!

These are not to scale, nor is the orbital path nor the 60 degree line entirely accurate; I just threw it together and eyeballed everything and you normally burn before you would pass into a new 'quadrant' on the bottom of the image - if you continue to draw the tangent line beyond the quadrant dividers, it passes into the one before the pink dot on both images and that would be the case if the orbit was wider, which it probably should be. When you draw the tangent line across Kerbin surface and through your orbital path, you are burning at the pink dot. Pick a spot where it crosses your path and draw directly towards the planet. Pick the spot it intersects with the surface and use whatever feature is on the line as a guide. I do this every time before I do a TMI and then double-check with Mun rise just before I do the burn. You can normally flip the map so it\'s horizontal instead of being top-down for the view after you\'ve done your corrections and gauge if the spot you picked is going to coincide with Mun rise. I basically do it this way just because it\'d be nice to know how to do it in case I don\'t have that luxury.

I figured out that 60 degrees was the optimal distance to let the orbiting bodies travel by using some simple math. I saw how long my average craft took to get to their altitude, what their orbital velocities were, and then how far along their orbit they would\'ve traveled in the time it took an average craft to arrive. I grabbed numbers from the wiki and both planets came out to about 60 degrees. If you want to adjust your orbital horizon to reach Minmus, that\'s an entirely different matter, but also not difficult once you understand why you\'re doing what you\'re doing to correct stuff.

[opticalshadow]

it might be costly pending on your build, but i found using rcs in conjuncture with sas prevents asparagus type ships from rotating in orbit.

[Tarmenius]

When i saw the condor, OHH GOD, IT LOOKS SO FREAKING AMAZING MAN!

Thank you very much. I\'m really glad you like it; I was afraid people might think it too 'normal and boring.'

-snip-

Good work, that\'s a very helpful diagram to compliment the process you described.

it might be costly pending on your build, but i found using rcs in conjuncture with sas prevents asparagus type ships from rotating in orbit.

They don\'t have an issue rolling while the ASAS is active, just when you turn it off for the gravity turns, though RCS would help make any manual corrections easier.

On a somewhat related note, I\'m currently re-working the Antares Mk16 to account for the fact that RCS tanks on top of half-size fuel tanks will break off when using warp. At least, they do for me. If this happens with anyone else, please let me know since I will likely be submitting a bug rerport for it. Fortunately, the half-size tanks seem to be the source of the issue, and using the regular tanks is fine. I should have a new design up shortly.

[Tarmenius]

Well, after a few more tests and a couple design changes, the Antares Mk16 has a new Lander. I\'ve updated the original post with images as well.