Kerbodyne SSTO Division: Omnibus Thread

[Wanderfound]

The first of the new Mk 3 range: the Kerbodyne Constellation.

Story at http://s1378.photobucket.com/user/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Constellation/story

Alternate format at http://s1378.photobucket.com/user/craigmotbey/slideshow/Kerbal/Beta/Kerbodyne%20Showroom/Constellation

Craft file at https://www.dropbox.com/s/cy2rq02dnp71mys/Kerbodyne%20Constellation.craft?dl=0

(warning: first attempt at one of these. Smooth handling, but not quite as effortless to orbit as I'd like)

[Jovus]

Wanderfound, you probably already know, but apparently FAR is giving way too much drag high in the atmosphere due to changes to how it handles skin drag high in atmo. So any designs you make may need retweaking once the next update comes out.

Likely they'll just have way more range than you intended.

[Wanderfound]

Wanderfound, you probably already know, but apparently FAR is giving way too much drag high in the atmosphere due to changes to how it handles skin drag high in atmo. So any designs you make may need retweaking once the next update comes out.

Likely they'll just have way more range than you intended.

Yup.

With ye olde version, the Constellation works but is a bit of a pig to fly. With the new one, it should fly like a proper Kerbodyne design.

My design output is likely to slow down for a while: combination of holiday nonsense and an urge to focus on career mode for a bit. I might get some useful low-tech designs from that, though.

[Wanderfound]

Sometimes, more is less. But at other times, more is just more.

Meet the Kerbodyne Cloudbreaker. With enough thrust, anything is possible.

Annotated flight test at http://s1378.photobucket.com/user/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Cloudbreaker/story

Alternate format at http://s1378.photobucket.com/user/craigmotbey/slideshow/Kerbal/Beta/Kerbodyne%20Showroom/Cloudbreaker

Craft file available at https://www.dropbox.com/s/2e3eq7xp84rvm9b/Kerbodyne%20Cloudbreaker.craft?dl=0

[Wanderfound]

Need a low-tech, early game spaceplane with good cargo capacity?

Here y'go...

The Kerbodyne Initiale.

Annotated flight test at http://s1378.photobucket.com/user/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Initiale/story

Alternate format at http://s1378.photobucket.com/user/craigmotbey/slideshow/Kerbal/Beta/Kerbodyne%20Showroom/Initiale

Craft file at https://www.dropbox.com/s/sdmvihw8k0f5msp/Kerbodyne%20Initiale.craft?dl=0

No fuel lines used for early-tech reasons; pump fuel manually if not using Goodspeed/TAC-FB.

[eddiew]

Nice to see some MK3 designs flying, thanks Wanderfound. And lol, that Cloudbreaker... it's an SSTO, but I'm not sure it's a spaceplane

...is it wrong that I looked at the Initiale and immediately thought "space goose"? Nonetheless I shall have to give that style of ship a go, what with all the new satellite contracts ^^

[Wanderfound]

...is it wrong that I looked at the Initiale and immediately thought "space goose"? Nonetheless I shall have to give that style of ship a go, what with all the new satellite contracts ^^

It could use a Kerbpaint detailing job, yes.

Initiale is a bit short on pitch authority by my usual standards, BTW; you may need to mash the S key occasionally rather than just letting SAS hold pitch for you. Built it that way to try and make something tolerant of rough piloting. If you've got the tech, swapping the horizontal AV-R8’s for canards as elevators would make it more responsive.

We really need some bigger stock jets; there are thirty-two Turbojets on the Cloudbreaker and it still needs the KR-2L lit to get off the pad.

Edited December 24, 2014 by Wanderfound

[Wanderfound]

Another low-tech high-practicality offering: the Kerbodyne Alkahest. Haven't unlocked RAPIERs yet? Got a probe you need deployed? Got some Kerbals that need training? We have the universal solution.

Craft file at https://www.dropbox.com/s/0xqrszlbnmlm1gj/Kerbodyne%20Alkahest.craft?dl=0

Annotated flight test at http://s1378.photobucket.com/user/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Alkahest/story

Alternate format at http://s1378.photobucket.com/user/craigmotbey/slideshow/Kerbal/Beta/Kerbodyne%20Showroom/Alkahest

[Wanderfound]

Gotcha RAPIERs? Time to upgrade!

Kerbodyne Alkahest RP4.

Annotated flight test at http://s1378.photobucket.com/user/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Alkahest%20RP4/story

Alternate format at http://s1378.photobucket.com/user/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Alkahest%20RP4/story

Craft file at https://www.dropbox.com/s/wc763czscxqwzpq/Kerbodyne%20Alkahest%20RP4.craft?dl=0

[Behemoth1702]

This is an amazing thread. I am barely getting to understand plane design and this guy makes it look easy, haha. Like "oh boy, another one? alright, let's take it to the forums.".

Great ressource to learn!

[Wanderfound]

This is an amazing thread. I am barely getting to understand plane design and this guy makes it look easy, haha. Like "oh boy, another one? alright, let's take it to the forums.".

Great ressource to learn!

Have a poke at the tutorial linked at the bottom of this post: http://forum.kerbalspaceprogram.com/threads/90747-Kerbodyne-SSTO-Division-Omnibus-Thread?p=1353891&viewfull=1#post1353891

Once you've got your head around how to use the tools provided, things become a lot easier.

[Wanderfound]

Another design featuring the hot new anhedral look that's all the rage this summer: the Kerbodyne Archer.

Annotated test flight at http://s1378.photobucket.com/user/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Archer/story

Alternate format at http://s1378.photobucket.com/user/craigmotbey/slideshow/Kerbal/Beta/Kerbodyne%20Showroom/Archer

Craft file at https://www.dropbox.com/s/c2gg8rd6rxjrkpu/Kerbodyne%20Archer.craft?dl=0

[Wanderfound]

Need some cash in your career game?

Like this: http://s1378.photobucket.com/user/craigmotbey/Kerbal/Spaceplane%20economics/story

Alternate format http://s1378.photobucket.com/user/craigmotbey/slideshow/Kerbal/Spaceplane%20economics

[eddiew]

Another design featuring the hot new anhedral look that's all the rage this summer: the Kerbodyne Archer.

Sleek, I like it - one of the better MK2-MK1 adapter craft

Having just earned my RAPIERs in 0.90, I figured it was time to do something about replacing the conventional lifter stages with something a little more civilized. But I didn't feel like a ten minute climb to orbit every time, so I took some inspiration from your old Goblin model Using a tweaked tech tree so I don't have vernors, or even RCS as yet, and there's nothing in my LKO to dock with, so these are just pure lift-and-shift packages, both with over 1.2 TWR in jet mode. Extended the nacelles for more fuel and carrying capacity.

The Slingshot (left) will take small probes up to ~2T to 200km+, while the Catapault edition (right) sacrifices fuel for an extra half-length cargo bay, and can take 3-3.5T to a stable 80km. The dummy probe top right has a delta-v of 4900, while the little gold one completed 3 satellite contracts around Kerbin, and will be bringing it's expensive science package back home in a few months.

Having piloted these birds, I may never make a spaceplane with less than 1.2 TWR again; it's just so much more fun when you can climb at 45 degrees, hands-off! The fast ascent stops me feeling like I should have just used a disposable rocket, and they're forgiving enough on delta-v that it doesn't matter if I don't get the perfect launch. I kicked Slingshot onto rockets at only mach 2.6, and it still had 888 delta-v left at 120km. With good piloting and a light load (or a can of fuel in the trunk), I reckon it might make Minmus orbit. Proper sporty little number, totally made the Kerbodyne Goblin my new benchmark craft. Anything with less grunt just isn't fun enough!

Interestingly, FAR tells me these aren't stable above 25km, but I've had no problems getting either to orbit or back down... maybe the brute force just makes aerodynamics go away. Both can re-enter, turn when low and slow, and both make it back to the runway even after an overshoot and 180 turnabout. Naturally I loaded them with enough chutes for an emergency anyway

[Wanderfound]

Red FAR numbers don't necessarily mean "unflyable"; they mean "not neutrally stable at this speed/altitude". With enough control surfaces (or vectored thrust: the high gimbal range of all those RAPIERs is probably helping a lot), you can control almost anything.

It's usually nicer not to have to, though.

BTW, see the "need some cash?" story above for how to launch a probe into a high orbit virtually for free. Just drop 'em off on the way to elsewhere.

Where the low TWR ships come into their own is interplanetary; strip it back to the minimum possible jet thrust, and use the weight saved for fuel and LV-Ns. My Duna and Laythe planes had barely enough kick to get off the runway.

Edited December 28, 2014 by Wanderfound

[Wanderfound]

BTW, the other probe launching trick: if the probe is in an orbit that the spaceplane can't reach, don't launch to a circular orbit: burn straight into an extreme elliptical orbit direct from launch.

Don't raise your periapsis out of the atmosphere at all; burn until your fuel is 99% gone and your apoapsis is as close to the desired orbit as possible, then drop the probe. Use the probe's own ÃŽâ€V to circularise at apoapsis (a couple of monoprop tanks can easily give several thousand ÃŽâ€V to a small probe, and circularising a high elliptical orbit takes very little fuel) , and rely on aerobraking to slow the spaceplane down.

Edited December 28, 2014 by Wanderfound

[Behemoth1702]

Wow, that nuke mission jet, amazing story man! Haha, nice!

[Wanderfound]

BTW, y'all get that the Alkahest variants and the Archer are basically the same airframe? It's another case of "get something that works, tweak it into everything you need".

The new SPH tools make dihedral and thrust balancing very easy. Set RCS Build Aid to Engine/Thrust mode, and put just the space engines in the first stage. Offset or rotate (depending on if you want anhedral/dihedral wings) the lateral engine pods to minimise torque. An/dihedral wings can be offset with an angled tailplane.

[Behemoth1702]

BTW, y'all get that the Alkahest variants and the Archer are basically the same airframe? It's another case of "get something that works, tweak it into everything you need".

The new SPH tools make dihedral and thrust balancing very easy. Set RCS Build Aid to Engine/Thrust mode, and put just the space engines in the first stage. Offset or rotate (depending on if you want anhedral/dihedral wings) the lateral engine pods to minimise torque. An/dihedral wings can be offset with an angled tailplane.

Yup, I saw that not much changed from the airframe on the archer.

I don't quite understand the 2nd part of your post. I can counteract a dihedral wing with an a tailplane with 2 vertical stabilizers that are facing "inward"? But does that not remove the stabilizing effect of dihedral as well?

Also - that engine offset thing I tried on my mk1 plane, it worked like a charm! But with multiple engines? Why only move the lateral engines? What if my lateral engines are the space engines? And what if then the thrust of the atmosphere engines is now off-center? I think you would have to re-balance ALL engines, eh? :-/

(btw I'm googeling a .... ton out of aerodynamics at the moment, FAR got me crazy!)

[Wanderfound]

Dihedral = aero surfaces angled up. Anhedral = aero surfaces angled down. Dihedral increases roll stability, anhedral increases roll agility. Both also add a bit of longitudinal stability, increasing with distance from CoM.

The offset weight distribution induced by vertical stabilisers often gives spaceplanes a bit of engine torque. You can fix this by angling your engines, or by shifting mass. Shifting wings moves a bit of mass, shifting engines (most easily done with lateral engine/fuel/intake pods) moves a lot (as well as moving torque). Balancing anhedral vs dihedral on wings and tailplanes (horizontal) can provide a bit of longitudinal stability at the cost of a bit of lift. Angling vertical stabilisers (tailfins) outwards gets a reduced version of the dihedral tailplane effect, but trades longitudinal stability for lift.

Everything in airframe design is a matter of competing tradeoffs.

Edited December 29, 2014 by Wanderfound

[Wanderfound]

They've finally cracked it: the Mk3 heavy lifter that flies like a Mk1.

The Kerbodyne Titan 8. Nothing this big should fly like that.

Story at http://s1378.photobucket.com/user/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Titan%208/story

Alternate format at http://s1378.photobucket.com/user/craigmotbey/slideshow/Kerbal/Beta/Kerbodyne%20Showroom/Titan%208

Craft file at https://www.dropbox.com/s/dt60cvztnllkop5/Kerbodyne%20Titan%208.craft?dl=0

[Brownhair2]

They've finally cracked it: the Mk3 heavy lifter that flies like a Mk1.

The Kerbodyne Titan 8. Nothing this big should fly like that.

http://i1378.photobucket.com/albums/ah120/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Titan%208/screenshot373_zpsef10e1d3.jpg

Story at http://s1378.photobucket.com/user/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Titan%208/story

Alternate format at http://s1378.photobucket.com/user/craigmotbey/slideshow/Kerbal/Beta/Kerbodyne%20Showroom/Titan%208

Craft file at https://www.dropbox.com/s/dt60cvztnllkop5/Kerbodyne%20Titan%208.craft?dl=0

This craft is cool, I downloaded it, and I noticed something: Your Clamp-o-Tron Sr. is facing the wrong way. Just thought you should know.

EDIT: Also, do you use any mods, or have some secret way of controlling it? Because when I tried flying it.. it did not like to climb.

Edited December 30, 2014 by Brownhair2

[Wanderfound]

This craft is cool, I downloaded it, and I noticed something: Your Clamp-o-Tron Sr. is facing the wrong way. Just thought you should know.

Whoopsie. Thanks; will fix.

[Behemoth1702]

Master of Planes - Wanderfound...

I have a big struggle with delta wing-planes and I figured might as well ask the guy with .... ton of amazing planes out there. My planes either can't handle AoAs of over roughly 15°, are unstable with slip or are not responsible enough.

Could you please look at this craft file here and help me figure out if this is at all to save?

http://i.imgur.com/yatlxqw.jpg

http://www./download/i2nmr5aczprx602/F*ck*ngD*lt*s.craft

All I wanted was a build with cargo, passengers, plenty of fuel and that's it. :-/

I think maybe I am having too much weight for too little wing? I think I need some more general guide lines about this stuff. :-/

[Wanderfound]

Okay: gave it a quick once over.

The basics aren't bad, but deltas are notoriously tricky for pitch and yaw stability; having the CoM right up the back of the plane makes things difficult.

It could use a bit more lift and span, so I extended the wings a touch, repositioned things a little and gave you more pitch authority: it was severely lacking in that.

It's all good up to to 28km:

But you will get a tiny bit of yaw instability after that:

For that, either spend an hour fiddling with aero surfaces to eliminate it (moar tailfin and shifting CoM forwards is probably what's needed) or just fly through it. A bit of SAS torque or a Vernor each side of the nose would help with that.

Craft file at https://www.dropbox.com/s/8ko36si0a2wsl7g/Deltatune.craft?dl=0