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6 hours ago, eddiew said:

Sideways cargo bay... genius! Looks much better than when people drill through the solid floor :)

Hehe, I thought it was a nice touch. And a kerbal can climb it if you set the opening angle right! (58% in that pic) Just a touch of "F" when you reach the hinge to get yourself into the bay and the airlock hatch.

 

Rune. Besides, I am starting to think Mk3 looks better sideways.

Edited by Rune
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On 3/16/2016 at 8:28 PM, Rune said:

Well I can say that this is SSTOrbit... at least. And I'm reading >1,500m/s on that tiny nuke alone whit a bit of LFO left over at circularization, so perhaps quite a bit more.

M8224xU.png

 

Rune. So yeah, the Vectors are "a bit" OP.

This craft is packing a lot of punch with a low part count! Really nice design work here!

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Ladies and gentlekerbs, I am very glad to confirm... It can indeed go to a lot of other places. Like, any place with a solid surface on the kerbol system, actually. And from anywhere but Eve, it can get itself back to orbit and keep on going. And yes... that includes single-staging Tylo. :cool:

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First of many public declarations of gratitude to @castille7 and @PointySideUp, my tireless and shiny new testing/art team, without whom this creation would have stayed on the hangar gathering dust.

 

Rune. Coming soon™. With surprises!

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7 minutes ago, Rune said:

Ladies and gentlekerbs, I am very glad to confirm... It can indeed go to a lot of other places. Like, any place with a solid surface on the kerbol system, actually. And from anywhere but Eve, it can get itself back to orbit and keep on going. And yes... that includes single-staging Tylo.

 

 

Rune. Coming soon™. With surprises!

Yup those new vector engines are awesome! Where do you refuel before the Tylo landing?

Edited by Majorjim
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11 minutes ago, Majorjim said:

Yup those new vector engines are awesome! Where do you refuel before the Tylo landing?

Bop. It's inclined, but it's the closest in terms of dV if you know your stuff and don't worry about the fastest possible transfer. Less than 1.5km/s to low Tylo orbit from there.

 

Rune. So, you know, about 4.5km/s of dV, even using it wrong (high isp propulsion first). If you use it like Scott would have us do, it's over 5.5.

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Well, mine has to take a back seat to Rune (1, for style and 2, for Tylo) but I've been everywhere else with it, now, and I'm quite fond of the Express. Though I do wish it was a tad more stable in flight. The craft file is in the YT description, if you want to improve on it :)

 

 

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26 minutes ago, Rune said:

Bop. It's inclined, but it's the closest in terms of dV if you know your stuff and don't worry about the fastest possible transfer. Less than 1.5km/s to low Tylo orbit from there.

 

Rune. So, you know, about 4.5km/s of dV, even using it wrong (high isp propulsion first). If you use it like Scott would have us do, it's over 5.5.

Nicely done! It looks really cool too. Kudos!

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13 minutes ago, Gojira1000 said:

Well, mine has to take a back seat to Rune (1, for style and 2, for Tylo) but I've been everywhere else with it, now, and I'm quite fond of the Express. Though I do wish it was a tad more stable in flight. The craft file is in the YT description, if you want to improve on it :)

Pretty cool, and with a nice video! I like the soundtrack a lot. :)

Mine can look really advanced but actually, once you abandon the RAPIER and truly embrace rocketry, the dV numbers are not that hard to match, surprisingly.

 

Rune. All it takes is to build what is basically a flying fuel tank.

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1458459070_screenshot276.jpg"K-razy One" my non-symmetry SSTO (3 kerbals+ 2+tonn cargo like 2medium monoprop tanks), and 700+ m/s dV on low orbit to dock with kerbin space station

ps^sorry for my poor english

Edited by *MajorTom*
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https://onedrive.live.com/redir?resid=7003A8806D8A6B2C!713&authkey=!AKArjxC_7Z_h9kk&ithint=file%2ccraft 

 

 

Quick Overview

 

  • Two long mark 2 cargo bays either side of CG to minimize loaded/unloaded CG shifting.
  • Four pairs of Big S delta wings containing most of the fuel.   Fuel also stored around CG with minimal shifts from full to empty.
  •  

    One Rapier engine.  Two pod mounted Panthers serving as boosters at lower altitude – when jettisoned, this uncovers the NERV engines mounted in front of them on the same pods.
  • Three Vernier lifting engines in the belly to assist horizontal take-off and landing in low gravity environments.
  • Liquid Fuel Capacity 3360 Units. Oxidizer Capacity 440 Units.
  • Fuelled but with empty cargo bay it has a take-off weight of 38 tonnes.
  • Has very small ailerons which cause sluggish roll response.   While this makes it easier to fly on keyboard, it does make lining up with runway at KSC tricky – recommended to land on the grass.
  • Unusually, it’s a taildragger.   Couldn’t get the layout to work any other way, sorry.  Deal with it.  
  • Designed to be flown with Kerbal Joint Reinforcement mod and TAC Fuel Balancer.

 

 

Staging Info

 

  1. Starts both Panthers in Dry mode and the Rapier.
  2. Jettisons the Panthers when they become useless.
  3. Starts up the NERV engines.

 

 

Abort Button – Toggles Panther engines between Dry and Wet mode.

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The above graph shows my speed/altitude profile and the different power sources in use.  Blue indicates where the Panthers were active in Dry mode.  Red indicates afterburner use.  The Rapier engine has the colour yellow on this chart,  the nukes a nice radioactive green.

What you'll notice - 

  • Up to 10km I'm gaining height faster than speed, and not attempting to pass the sound barrier.
  • At 10km we nose down and use afterburner to get through the high drag  transonic regime as fast as possible.
  • Speed and altitude mainly increase together but comparatively small deviations from this trend, where speed increase is not matched by height gain, cause enormous increase in temperature.


Pictures from Flight & flying tips

Spoiler

 

I’m flying with keyboard controls only so am relying on pitch trim – if you are doing the same, recommend you pay close attention to this picture and set that exact amount of up trim before engine start.  Pitch trim is good because in the longer term , the aircraft will settle into the angle of attack you trimmed for, whereas SAS just holds a particular nose angle  regardless of aerodynamic circumstances.  There will be short term fluctuations however, particularly after a transition – and we’ve just transitioned from the runway to flying.    If the nose starts pitching up too much and speed begins to decay,  use SAS for a couple seconds to quell the deviation.

 

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Mach 1.7 is the velocity at which Panthers produce peak power in dry mode , unfortunately they also loose thrust very rapidly with altitude in dry mode whatever the airspeed.

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Mach 2.5 is the optimum speed for them in Afterburner.  In Afterburner the loss of thrust is not so rapid with increasing altitude, however thrust falls off a cliff above mach 2.5... by 2.9 it's probably best to jettison these engines, they're just dead weight.

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Mach 3.7 is the optimum speed for Rapier engines and thrust tails off only slowly with increasing airspeed.  Above 23km however, thrust halves with each additional 1.5km in altitude.   On one engine we can get up to about 24.5km, two would increase that a little, but not worth the extra 2 tons dead weight that must be carried out the atmosphere.

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Nukes join the party..

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Mach 5 at 29km, things are getting hot .  Was very relieved when it started climbing again.

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On our way up 

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Final approach

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Horizontal landing, using the Verniers to translate upwards as lifting engines.

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Final result - parked on the greater flats with 900m/s remaining.   Kerbal engineer only takes account of the fuel in the pre-coolers in its delta v, doesn't allow for the fuel in the wings which the nuke engines wouldn't be able to access without TacFuelBalancer or transferring manually.


Design Rationale 

 

 

Spoiler

 

1.       This spaceplane was optimised for deep space missions with less dense scientific payloads.  Hauling full fuel tanks or IRSU equipment to low Kerbin orbit is probably better done by something with more thrust and lots of oxidizer. 

 

2.       For the interplanetary capability I had in mind, I wanted NERV engines and for as much tankage as possible to consist of LF rather than Oxidizer.   That way, Delta V potential when refuelled by an IRSU facility is maximised.

 

3.       In order to be refuelled, it should be capable of reaching a Minmus IRSU facility unaided, with a light load.

 

4.       In case you hadn’t guessed, efficiency trumped aesthetic considerations.

 

5.       To this end, the airplane was designed to accelerate to orbit from the air-breathing ceiling with the meagre thrust of NERV engines alone.  Two NERVs would be provided, which is the maximum a vehicle of this size can reasonably accommodate without the mass of the engines themselves impacting performance.  Nevertheless it is clear the design needs to have very low drag at high altitudes.  

 

6.       Assuming due diligence with regard to parasite drag, the main source of drag in very high altitude flight are the wings.  In turn, the amount of drag a wing makes in supporting a vehicle of a given weight, is dependent on its angle of attack.   Lowest drag, for a certain amount of lift, occurs at 2 degrees AoA at low speeds rising to an optimum of 5 degrees at very high speeds.

 

7.       However, maintaining the most efficient angles of attack is likely to result in the vehicle not gaining altitude quickly enough as speed rises and being destroyed by overheating, unless the aircraft has very large wing area.

 

8.       One obvious objection to adding extra wings is that they become dead weight that reduces delta V out of the atmosphere.  This was addressed by using the Big-S delta wing part exclusively, since it has the same mass: fuel volume ratio as other tank parts, yet also forms a lifting surface.  In fact it’s mass: lift rating ratio is as good as any other wing. 

 

9.       In this design therefore I strove to minimise the amount of fuselage tanks which add weight but no lift, in favour of as many wing tanks as possible, which at least provide lift to offset the mass of the fuel they carry.    

 

10.     The wing layout I came up with fits about as much area as you could plausibly fit on a fuselage of this size without resorting to clipping or biplane/triplane multiplane layouts not suited to high speed flight.

 

11.   In a similar vein, I’ve moved away from using clipping in the propulsion arrangement.  My recent designs all featured Rapiers attached to the rear node of NERVs and offset so that both can be used simultaneously, with tail cones attached and offset last inline to get the benefit of lower drag without actually blocking the nozzle.   Such impossible layouts minimise the frontal area of the craft but are gamey and also force a 1:1 ratio of engine types, which may not be desired.

 

12.   Furthermore, attaching all the engines to the rear of the fuselage like this makes the aircraft excessively tail heavy when empty.

 

13.   So, I decided to return to the trimotor layout as used on my very first spaceplanes, which avoids such CG problems and enjoys perfect thrust symmetry. 

 

14.   However, where these early designs used 2 RAPIER and 1 NERV, I now use 2 Nuke engines and only a single Rapier.  Thrust falls off so rapidly with increasing altitude that adding a second Rapier only increases the air breathing ceiling from 24.5 to 26.5 km for the cost of 2 tonnes engine mass that becomes dead weight once orbit is achieved.  OTOH, dropping down to a single NERV means carrying large quantities of oxidizer, since this engine alone will not have enough power to boost the vehicle to orbit.

 

15.   Structurally, it would have made more sense to mount the engine pods beneath the wings, but that results in a pitch moment that can overwhelm the reaction wheels in the upper atmosphere.  Handling considerations took precedence and the pods were attached to the sides of the fuselage at the exact midpoint of the fuselage height, and the wings mounted to the pods in turn.   Keeps the thrust axis right on the centre of gravity but necessitates the use of Kerbal joint reinforcement.

 

16.   Flight testing revealed the need for the two Panthers.   Due to its large wing area this design generates a lot of drag when trying to fly fast at low altitudes, which meant it was unable to penetrate the sound barrier below 10km.   Unfortunately the Rapier doesn’t produce much power below mach 1, and with only a single engine the climb to 10km could take almost 20 minutes.   Because the available thrust was only just greater than that needed to merely maintain level flight, the design suffered excess “gravity losses” and would use half its fuel in the subsonic phase of flight.

 

17.   In dry mode, the Panthers double the available power and triple the surplus power available for climb.  Furthermore, they have an ISP of 9000 compared to 3800 for the Rapier.   Combined with the reduced “gravity losses”, fuel usage up to 10km is cut by an order of magnitude.

 

 

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2 hours ago, AeroGav said:

Snip

Whoa, cool explanation! I like it when people think about their designs in a scientific way, and show us the whole process.

 

Rune. Also, a SSTMinmus is no joke, kudos!

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3 hours ago, Rune said:

Whoa, cool explanation! I like it when people think about their designs in a scientific way, and show us the whole process.

 

Rune. Also, a SSTMinmus is no joke, kudos!

Thanks , but I get the feeling that if you'd built it,  you'd have found a way to make her look good !

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5 minutes ago, AeroGav said:

Thanks , but I get the feeling that if you'd built it,  you'd have found a way to make her look good different !

I think that design is actually quite nice.

Rune sure is one of the giftet builders here, especially when it comes to aesthetically pleasing designs, but I feel you are well on your own way too. Your post speaks about a deep understanding of the game and SSTO physics... keep it up, start new builds, share them and improve even more. I'm looking forward to see more of your stuff!

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Well that was easy!

 After literally five minutes work I got this into a 220k orbit with 1782 units of fuel left. Vectors are either super awesome or OP depending on how you look at it! :D

 You can see how rough and quickly made this is from the exposed struts and fuel lines. I was in orbit in what felt like seconds. My ascent was horrible and if I spent less than a day on this refining it I think I could send it and some cargo/ISRU anywhere!

 

2lbfgq9.jpg

 

10i9ipy.jpg

Edited by Majorjim
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28 minutes ago, Majorjim said:

Well that was easy!

 After literally five minutes work I got this into a 220k orbit with 1782 units of fuel left. Vectors are either super awesome or OP depending on how you look at it! :D

 You can see how rough and quickly made this is from the exposed struts and fuel lines. I was in orbit in what felt like seconds. My ascent was horrible and if I spent less than a day on this refining it I think I could send it and some cargo/ISRU anywhere!

Cool! No you can go about the business of turning it into a SSTA, and finding out just exactly how easy or hard that is. If I can give one tip, make sure that you can land where you are going!

 

Rune. As I said before, getting the dV is pretty straightforward.

Edited by Rune
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5 hours ago, Rune said:

Cool! No you can go about the business of turning it into a SSTA, and finding out just exactly how easy or hard that is. If I can give one tip, make sure that you can land where you are going!

 

Rune. I said efore, getting the dV is pretty straightforward.

Well yes getting into orbit with some fuel left was a cinch. I just landed it too first time, glides like a dream. plenty of control with nothing more than the torque from that pod. And airless landings will be a case of TWR and COT/COM balancing but with the sheer power and gimble of the vectors it shouldn't be too hard. She is heavy though. It almost felt like cheating! Ho hum. I am knee deep in aeroshells and constellation lifters so I will come back to it after that. Cheers. I prostrate myself in the shadow of your SSTO magnificence @Rune!

Edited by Majorjim
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The Easter weekend gave me some time to play with my creation from  a few posts ago.

In that thread, I reckoned it could lift a light scientific payload to Minmus,  and put a heavier payload eg. IRSU in orbit but not take it to Minmus.     This weekend I thought I better show it could live up to those claims.   First question, can you  even fit an IRSU setup in a MK2? Unfortunately I ran out of weekend to address any further questions, because this test flight took a bit longer than anticipated..

1_zpsdgfhttcc.jpg

Well,  I'd forgotten how much lighter the small converter and drill are than the big one.   Yep, their efficiency is awful.   But,  I was able to get all the way to Minmus with 400dV remaining - only 500 less than going up empty.   This is only my third launch of this aircraft, so i guess my flying is still improving.   Note, I'm still matching inclination of Minmus after reaching orbit.  Could save a bit more if I knew how to time my launch and take off inclined, or burn direct to Minmus with no parking orbit.

Of course, this is a bit of a "Spam in a can" setup.  How can our kerbonauts tolerate such close confines for months  years on end,  without being romantically involved?   And if they are romantically involved,  some things must never be shared...  i presume they must go on EVA every time one of them wants to use the bathroom.    I'd give it half an hour before stepping outside , if i were you....

 

400 spare delta V means I was able to get into a polar orbit and do a planetary survey before setting down.       Once on terra firma,  the slow rate of fuel production proved to be a non-issue due to the bug that makes solar panels continue to produce power on Minmus at nighttime. Just left it in time acceleration for a couple of Minmus days and we were full up again.  Time to go home... or maybe not..

 

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Spoiler

My first Duna plane was also a MK2, but had it's wing built out of just one Big S Delta, albeit with three Big S strakes and a swept wing helping out.   It also lacked IRSU so was coming in fully fuelled,   landing speeds were rather worrying despite Vernier lift engines.  

2015-11-13_00029_zpshkgkyztg.jpg

Landing at these speeds required quick save about 10 seconds before impact touchdown and about half a dozen attempts to put her down in less than fifty one pieces

I was pleasantly surprised to find that the transfer orbit direct from Minmus took less than half our fuel, however in view of the above I elected to dump nearly all of it to try reduce our kinetic energy on landing impact.   I also opened the cargo bay for extra drag since we were in danger of overshooting our landing site.

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64 M/S ! That's a lot better, shows what 4 big S wings can do.

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At bit more back stick, and a squirt from the Vernier lift engines, we're down to 41 M/S.

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Full back stick and 36 M/S.   15 degrees AoA is as much as you can get out of this airframe..

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32 M/S   SINK RATE ! WHOOP WHOOP  PULL UP !  

 

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Keep this up,  they'll give me an orange suit as well ! 

Mining on Duna was a lot harder work than on Minmus because the solar panels really do stop producing overnight.   And unfortunately,  the drill has to be manually restarted every time it shuts down for a lack of power, while the converter just picks up where it left off.  Given that the process is bottlenecked by the drilling rate, that's a bind.   After restarting my drill 30 times,   I was quite glad to see the back of this place..

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Spoiler

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Podsy and Virry would rather I level off to accelerate through the sound barrier a bit higher up.

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That mountain reaches 7000m

 

  .

Spoiler

This is my first ever flight to Laythe.   Fuel was much tighter than on the Duna leg, thanks to my lousy understanding of orbital mechanics.  I couldn't believe how much extra fuel it took once captured by Jool to work a Laythe encounter.   And then to actually stay captured by Laythe and not just have it sling you out to Alpha Centauri,  or on a death plunge into the depths of Jool.  Seems to require a load of fuel or some VERY brave aerobraking manuvers.

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Dead stick approach.   Of course there wasn't enough for a survey this time.   I'll try to land on the top of that Island, if there's no Ore on the summit, then i can release the brakes and hope to find some as we roll downhill.  

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No need for lift engines, fortunately.

 

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Spoiler

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As luck would have it, that Island is an ore hotspot.  Unfortunately, it looks like this is the last stop on our tour.      It appears we've been hit by the occlusion bug, I cannot use the NERVs because the game thinks they are stowed, unless i open the cargo bay.   Opening the cargo bay in Laythe's atmosphere creates too much drag to exceed mach 1.    We didn't have this problem on Duna and I can't seem to recreate this fault with the same craft down on Kerbin, but i'm at a loss to solve it on this one.

Next week,  it's time to verify this SSTOs cargo ability.    The centre of lift is exactly between the two cargo bays, so i'm not anticipating any problems ,  but  i've put together a little "upper stage" module to try it out -

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This one man exploration module has a mk 1 crew cabin so he doesn't have to spend the whole interplanetary leg in the lander can, which serves as the "command module".   The ion engine cluster, with reaction wheel, battery, command chair, and small xenon tank, can be undocked from the rest of the craft and hopefully be light enough  to land on ion power alone... 

 

Edited by AeroGav
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