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Somtaaw

Seeking mk3 passenger spaceplane (challenge?)

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I don't really think this thread belongs in Spacecraft Exchange, because I'm not actually showing off my own designs... but we don't exactly have a thread for "requesting" designs so lesser of known evils I suppose...

 

but I digress, I'm seeking a Mk.3 Passenger spaceplane, for the purpose of quickly getting newly hired Kerbalnauts experience in, shall we say a 'supervised' environment. Minimum capability that I'm looking for here:

-must have at least one Mk3 crew passnger cabins

-capable of interplanetary flight (Dres or farther)

-VTOL landings on low-grav moons and planets

-full science package

-capable of powered re-entry & landing to KSC

-Stock parts

 

If you're looking for additional challenge(s), in descending desirability:

-capable of launching one, or more, mid-size satellites approximately the length of the mk-2 (short) cargobay in a single expedition

-NOT be self-refuelling, provisions for external fuel drop tanks or docking to refuel yes, but no mining and refining mounted

-FAR & stock aero capability friendly

-Aesthestically pleasing, not simply function over form. 

 

 

And just because I want to try and fall within the boundaries of this sub-forum, the CSF SSTO that I've designed so far (although still haven't actually flown her)

2eZmTi7.png

Edited by Somtaaw
moved screenshot from Dropbox to imgur

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Actually, funny enough. Im working on a design just like that myself.

tiuqHvj.png

It's called the K.S.S Kermandy (heavily inspired by the Normandy SR-2).

It "should" be able to meet all the categories except for the FAR and self refuelling one. It has an ISRU converter, but no actual mining capabilities, so you'll have to use a probe to do that.

And the reason i'm saying should, is because i don't actually know how to go interplanetary. the only planet i've visited, is Mun, once.

But, because hyper edit is a stock thing now, i should be able to test everything, except range. But i guess i should try to visit some planet other than Mun.

 

Right now im working on a lifter capable of taking this thing into orbit. I want to make it so that it can carry two orange Jumbo tanks into orbit with it, or whatever you can fit in the cargo-bay.

 

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Kermany looks nice, a bit longer than is my taste, and I'd end up stripping the ISRU out from it but otherwise nice. And the SR-2 feel is love, Mass Effect was really great right up until "ha *&^% you, those hours and hours of agonizing choices meant absolutely nothing! bwahahaha". However on the downside, she looks a bit fragile for atmospheric flight, at least re-entry.

 

For testing, since you already use HyperEdit, drop it directly into space +/- 1 second from a space station, and "pretend" you'd just undocked for a range test from there. Going interplanetary is pretty much the same as Munar and Minmunar trips, just with considerably more fuel and usually thrust involved. But the basic's are essentially the same.

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Small little bump to keep the search alive. After a long search, I've noticed all spaceplanes come in two primary variants. Either it's designed to be sporty & fun, with emphasis on the mk2 frame, very low passenger capability, and possible self-fuelling using a very very limited cargo capacity. Or they're mk3 monsters, designed to loft entire space stations in a single flight, sometimes with an huge passenger capability to crew the space station.

 

Any variants are really in the mk 2 end of the spectrum, so I have not been able to find a mk3, designed to take 20 or more Kerbals on a multi-planet training flight, but with zero or minimal cargo capacity.

 

An amendment to the list of what I'm searching for.... this mk3 does not have to be SSTO capable.Think of it as a high passenger, low cargo variant American space shuttle. Vertical, rocket-aided ascension, horizontal plane landings.

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1 hour ago, Chris_2 said:

I made a quick crew variant of my spaceplane. Same action keys and stuff. There is a nerva in the cargobay, and VTOL landing engines (and solar panels) in the 'bomb bays'.CEkNqsS.jpg

Download: https://kerbalx.com/Chris_2/Enterprise-crew

Wow that looks nice! What is its range?

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27 minutes ago, Firemetal said:

Wow that looks nice! What is its range?

It's doesn't have the range of it's mining brother. But it also is almost 15t lighter and has a big empty cargobay, so you could load up a lot of extra liquid fuel and get to Minmus. And when docking them together you could have a big self-sustaining interplanetary mission.

KUB6BRm.jpg

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On 25/09/2016 at 7:36 PM, Somtaaw said:

Small little bump to keep the search alive. After a long search, I've noticed all spaceplanes come in two primary variants. Either it's designed to be sporty & fun, with emphasis on the mk2 frame, very low passenger capability, and possible self-fuelling using a very very limited cargo capacity. Or they're mk3 monsters, designed to loft entire space stations in a single flight, sometimes with an huge passenger capability to crew the space station.

 

Any variants are really in the mk 2 end of the spectrum, so I have not been able to find a mk3, designed to take 20 or more Kerbals on a multi-planet training flight, but with zero or minimal cargo capacity.

 

An amendment to the list of what I'm searching for.... this mk3 does not have to be SSTO capable.Think of it as a high passenger, low cargo variant American space shuttle. Vertical, rocket-aided ascension, horizontal plane landings.

SSTO basically come in two variants.   RAPIER only craft, with relatively (for a spaceplane) low mass fraction in its engines, hence decent cargo capability to orbit.  But also these engines have miserable ISP so go no further than low orbit.  Or you can go with NERVs.  The heavy engines swallow a lot of your payload mass fraction, but their high ISP means you can go to Duna single stage - just.

I think it's sensible of you to relax the requirement for strict 100% reusability.  POssibly compare on cost per passenger launched instead, to encourage the highest possible degree of reusability.

Vertical launch with solid boosters isn't the only technique this enables.

You can also bring along Whiplash jets on decouplers to help with launch when fully loaded from Kerbin.  This reduces the number of Rapiers you need to carry across the solar system.  Thanks to the lower gravity, you won't miss those boosters launching out of Laythe.

Here is an example of that kind of design, but would need scaling up to mk3 size.

https://kerbalx.com/AeroGav/PENTA-STAR-REDUX

Stock Mk3 are tricky for me.

The engines you want to use are all 1.25m size.   There's a nice 2.5m mount that has nodes for three 1.25m engines - relatively low drag for such a thing.  But you'll need an adapter to take you down from mk3 to 2.5m size first.  These are all LF/O filled - when a long range craft like this requires little or no oxidizer, relying on nukes.   And that adapter is going to be at the rear , aft of CG.   You'll need another LF/O tank near the front to not have CG shift around as you run your LF/O engines.    So all in all you waste kraptons of tank space or lug around a fuel with poor ISP.

Still , I've never really come up with a good mk3, so I feel as though i should keep at this.    But it makes you wonder if the unbeatable kerbals/ton of the mk3 pax cabin is just a trap for the unwary.

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Ok, over my weekend off, I updated the Penta Star mk2 freighter to something better looking and that seems to have even higher performance 

https://kerbalx.com/AeroGav/Pentastar-Santos-II

Spoiler


20161014103310_1_zpsrmshba3i.jpg

20161014105818_1_zpspmhn9t0u.jpg


 

I also started developing a ship for this challenge.

It has a docking port, a large irsu converter and the plan is to put a small drill and some radioisotope thermal generators in the service bay later so it can refuel at 10,000x time warp on Minmus.  I need to add some vernier motors to the belly so it can do horizontal landings on low grav worlds and on Duna.

The basics are 78Ton laden weight.  2 Whiplash, 2 NERV, 1 Rapier and 2 Terriers.     The terriers & whiplash are boosters for the launch from kerbin,  they get dropped during the launch sequence.

It seems pretty efficient,  the first iteration of this ship looked to have enough delta v to reach Minmus.

https://kerbalx.com/AeroGav/mk3-pax-er2

20161014155325_1_zpsmnkzbq6e.jpg

20161014152307_1_zpsnvfmed47.jpg

20161014151434_1_zps77ioz54f.jpg

 

 

 

The mk2 version added another 1600 units of LF.

I'm sometimes guilty of overthinking and obsessing on efficiency, forgetting that "more is more".

It's getting to be quite a complex design already.  Swapping some of those dry modular wing panels for big S strakes componded into rectangular slabs (like i already have done for 1200 lf) is a prospect that fills me with dread.

 

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Speaking of over-engineered overkill, this might be a little more than you had in mind.

https://kerbalx.com/NoobTool/Czar-Galactica-Mk-3-Heavy-Crew-Transport

Rs6CobD.jpg

The Czar Galactica Mk3 Heavy Crew Transport

Economy seating for 150 Kerbals, Capable of reaching Minmus or an asteroid intercept for refueling with on-board mining equipment, Room in the forward cargo bay for a full science load-out (along with a rover or VTOL for biome hopping if you wish). I used it to fly 150 Kerbals to Duna and back for the Elon's Problem Challenge posted in the forums.

As far as aesthetics, I think she's pretty sexy for a bbw.

 

 

Edited by NoobTool

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https://kerbalx.com/AeroGav/Kerboliner-Mk3-Extended-Range

I've continued to develop my ship, I was really worried about getting out of Kerbin with enough delta V to reach Minmus and refuel, but if anything it could go further.  Pretty confident it'll work fine on Duna and low grav worlds.

Unfortunately the propulsion architecture i chose, means we're a bit too weak on Laythe, with those boosters already discarded.  We have to rely on the nukes far too much, and as a result struggle to make our next fuelling stop.

I think I'll have to scale the design up to 2 passenger cabins, the one cab design you always end up with too many or not enough of a certain kind of engine, when mounting in symmetric pairs.

Here's a video of it launching.  Towards the end, we get some IVA shots

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The thing I use for crew training is quite smaller than you request, but hey, for the sake of argument:

YgOSzlW.png

Specifically designed to train six kerbals at a time to lvl3, by taking them to Minmus to plant some flags, briefly touching interplanetary space, and making a Mun flyby on the way back. The dV budget is totally overkill for that, with more than 3,5km/s on LKO, so pretty capable of interplanetary burns.

 

Rune. Not going fully IP means the whole mission is under 15 days of calendar time.

Edited by Rune

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Well , it seems I've been overthinking this.

Most of my spaceplanes are freighters, or pod-only interplanetary craft.     The cabin doesn't provide much mass to counterbalance the engines at the rear.  And I need my CG to be in the middle of the cargo bay , and in the middle of all the fuel tanks, to keep my CG stable as fuel burns off and cargo is unloaded. .

That means one engine at the rear and the rest  mounted on the side of the fuselage.    That gets in the way of the wing, unless you mount it to the outside of the engine pods (looks weird and a bit flexy).  So I end up making a tunnel around the side engines made from wing parts.  It makes it much harder to work on the design though, especially if you need to change something about those engines !

But for this mission, we have the luxury of a nice heavy, unchanging mass that will always be part of our ship (the crew cabins).    All the engines can go at the back again, no more engine tunnel !  If I had realised this earlier , I might not have used engine nacelles at all, and just put it all on the back of the fuselage on a quad coupler.  However, sticking with nacelles does make it easier to have separating engines, something I'm still keen to play with.  Rather than the boring choice of 3 RAPIER 3 NERV.

Without the engine tunnel, there is no biplane inboard wing.  The fuselage just blends straight into the back-to-back Big S wings.  

And we gained extra weight, with more engines, an extra passenger cabin to balance the engines,  and a mk3 liquid fuel fuselage section up front (which balances the weight of the fuel in the engine nacelles).

It flies very different to my usual designs, which have much lower wing loading.  I really like the look though.

20161022170105_1_zpsdnuggt4z.jpg

 

I had expected that less wings would make it faster, at least in the lower atmosphere, and make it easier to get up to the speeds where the RAPIER and WHIPLASH start to get a power boost from the ram air effect.   On my usual designs, I sometimes have to climb up so high to avoid the drag, that I lose power due to the air being thin.  

However, I'm getting significantly worse lift:drag ratios.   I need 5 degrees AoA  to fly at 5km and 240m/s,  we're close to the sound barrier there and the large AoA makes horrible drag.  Lower down the air is too thick.   I had to relearn how to get through the sound barrier - it took till my second flight.  

20161022170616_1_zpswggzelvo.jpg

Above - we will not go to space today.     We used rockets and a shallow dive to get through the sound barrier, but after levelling off and cancelling the rockets,  our drag exceeds our thrust and our lift is less than our weight.  Ouch.

20161022172226_1_zps01tcxzvr.jpg

Above - we will go to space today. Same airplane.  Very minor difference in technique.   Same lift,  more thrust , less drag.  

 The speed run might have suited the small wings better, since it's best below 20km, where there is more power for the engines, but the old design had too much wing to go over mach 4 efficiently any lower down.

After the jets shut off,   the lift drag ratios were closer to what i experienced on the old design , but we were lower down in the atmosphere, and hotter, at each mach number milestone.  I guess that's why they give these mk3 fuselage parts such good heat tolerance !

 

Job for next week - try panelling in the underbelly a little more, to give us more lift, find out where the happy medium is.  Also i need to remember, this thing has to land off world on Laythe , Duna . 

PS - that "Firefox" canard is actually two all-moving tailplanes mounted back to back, with an advanced canard set on the tips.

 

Edited by AeroGav

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44 minutes ago, AeroGav said:

Well , it seems I've been overthinking this.

Most of my spaceplanes are freighters, or pod-only interplanetary craft.     The cabin doesn't provide much mass to counterbalance the engines at the rear.  And I need my CG to be in the middle of the cargo bay , and in the middle of all the fuel tanks, to keep my CG stable as fuel burns off and cargo is unloaded. .

That means one engine at the rear and the rest  mounted on the side of the fuselage.    That gets in the way of the wing, unless you mount it to the outside of the engine pods (looks weird and a bit flexy).  So I end up making a tunnel around the side engines made from wing parts.  It makes it much harder to work on the design though, especially if you need to change something about those engines !

But for this mission, we have the luxury of a nice heavy, unchanging mass that will always be part of our ship (the crew cabins).    All the engines can go at the back again, no more engine tunnel !  If I had realised this earlier , I might not have used engine nacelles at all, and just put it all on the back of the fuselage on a quad coupler.  However, sticking with nacelles does make it easier to have separating engines, something I'm still keen to play with.  Rather than the boring choice of 3 RAPIER 3 NERV.

Without the engine tunnel, there is no biplane inboard wing.  The fuselage just blends straight into the back-to-back Big S wings.  

And we gained extra weight, with more engines, an extra passenger cabin to balance the engines,  and a mk3 liquid fuel fuselage section up front (which balances the weight of the fuel in the engine nacelles).

It flies very different to my usual designs, which have much lower wing loading.  I really like the look though.

20161022170105_1_zpsdnuggt4z.jpg

 

I had expected that less wings would make it faster, at least in the lower atmosphere, and make it easier to get up to the speeds where the RAPIER and WHIPLASH start to get a power boost from the ram air effect.   On my usual designs, I sometimes have to climb up so high to avoid the drag, that I lose power due to the air being thin.  

However, I'm getting significantly worse lift:drag ratios.   I need 5 degrees AoA  to fly at 5km and 240m/s,  we're close to the sound barrier there and the large AoA makes horrible drag.  Lower down the air is too thick.   I had to relearn how to get through the sound barrier - it took till my second flight.  

20161022170616_1_zpswggzelvo.jpg

Above - we will not go to space today.     We used rockets and a shallow dive to get through the sound barrier, but after levelling off and cancelling the rockets,  our drag exceeds our thrust and our lift is less than our weight.  Ouch.

20161022170112_1_zpshj5d9nzh.jpg

Above - we will go to space today. Same airplane.  Very minor difference in technique.   More lift and less drag.  

 The speed run might have suited the small wings better, since it's best below 20km, where there is more power for the engines, but the old design had too much wing to go over mach 4 efficiently any lower down.

After the jets shut off,   the lift drag ratios were closer to what i experienced on the old design , but we were lower down in the atmosphere, and hotter, at each mach number milestone.  I guess that's why they give these mk3 fuselage parts such good heat tolerance !

 

Job for next week - try panelling in the underbelly a little more, to give us more lift, find out where the happy medium is.  Also i need to remember, this thing has to land off world on Laythe , Duna . 

PS - that "Firefox" canard is actually two all-moving tailplanes mounted back to back, with an advanced canard set on the tips.

 

THAT'S NO SSTO! It has a decoupler on it!

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On 22/10/2016 at 6:35 PM, AeroGav said:

20161022172226_1_zps01tcxzvr.jpg

 

https://kerbalx.com/AeroGav/Kerboliner-Stretch-36-Super

Yikes.   This turned into a big project.  I kept working on the above design, till it grew to 155 parts.   Mostly extra wing segments TBH.

110 Tons launch weight,  TWR is only 0.3 according to RCS build aid.

The extra wings actually make it easier to get through the sound barrier.   I think if you're going to do a high wing loading design you need either 

  • a buttload of power
  • skinny, low drag fuselage
  • wings angled at 5 degrees incidence, so the fuselage can be aligned with prograde while your stubby wings make lift

....or the drag from flying at high speed with high alpha down on the deck just kills you.

It no longer looks quite so hypersonic,   more like a Handley Page Victor / Blackburn Buccaneer with its cranked arrow/crescent wing.

20161028163504_1_zps7h2y07a6.jpg

20161028181701_1_zps0dxzaxbn.jpg
Taking off from Duna, Ike watches on...

Spoiler

 

20161028164118_1_zpswxe0rndu.jpg

OK from this angle it does look somewhat hypersonic..

20161028201210_1_zpstzsv2qhi.jpg

Flight testing on Laythe..

 

What took most of my time however, was getting it to land on Duna. It still has a higher wing loading than most of my designs.   Worse, it was very prone to tail stikes, which caused additional part decoupling beyond what the designer intended.   Also, the structure was very weak.   Touching down at more than 2.3g caused the sponsons to break away from the main fuselage, then be in collision with the various wing bits still attached due to overlapping, in a cascade of self-disassembly.   Must have spent a whole day crashing the thing looking at the F3 logs trying to work out which joint failed first.

Anyway, it's now a bit stronger.   This version, once I got the technique down,  I was able to land reliably.  Time to declare victory and get a break from this airplane !

 

 

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I disappear for a month and the thread explodes :D

 

With how much you're posting @AeroGav, I'm gonna have to be adding you to the OP for notable contributions to the concept challenge.

@Rune, thanks for your submission, you're right it's a bit smaller than I was originally looking for, you mentioned it being a mere 15 days mission time to get 6 Kerbals to 3 star which sounds quite reasonable and worthy of my intended goal of "fast training crew".

@NoobTool, you're right that is one sexy bbw plane, and with room for upto 150 Kerbals and that flight power I'd have to take her out for a spin on as close to a full trip as I can. Maybe I'll fly her for my first extra-Kerbin, non-Duna destination manned mission craft. Everything else I've "flown" to date, have been unmanned refuelling stations & communication relay satellitess (in the 1.0 era).

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@Somtaaw

I hope it works for you. I recently tried moving the craft file of one of the derivative variants to a new save game, and it seems that not all of the strut connections made the move. It had me concerned that the same would happen with the uploaded craft files. Pretty disappointing, strutting the main wings on was a major pain. If you try it out, let me know if it works for you. I would also recommend the Mk 3 EX variant. Many of the lessons I learned from flying the Duna mission went into that, it should be a more capable craft. They're built from the tail forward to allow the dorsal and ventral fuselages to be fairly easily reconfigured (if you wanted more passenger space than the EX offers).

Edited by NoobTool

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OK , something a little simpler after that over-engineered monster :

20161028163504_1_zps7h2y07a6.jpg

I present the Star Empress

20161110193214_1_zpsp2b26ver.jpg

3 Rapiers, 3 Nukes for 3 mk3 cabins, 48 Kerbal capacity.  Much lower part count, 100% re-usable this time , no boost engines for launch out of Kerbin.

No IRSU and does not feature the Kerboliner's "land anywhere ability", but it does have a lot of delta v to orbit.

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