1.0.2 Can anyone get a Mk3 SSTO spaceplane in orbit?

[GoSlash27]

Here's an example of a very simple Mk.3 spaceplane for 1.1.3.

30 tonnes of payload to LKO with plenty of fuel reserve for the trip home.
About 26% payload fraction, 1 engine per 32t of spaceplane, 1 wing , precooler intake, and Mk2 fuel tank per engine.

This is a bit close to the "underpowered" end of the spectrum.

Best,
-Slashy

1 hour ago, sal_vager said:

This is a rather old thread guys...

D'oh!

Sorry... *sheepish grin*

[foamyesque]

What actually is the payload there, @GoSlash27? I don't see any cargo bays or docking ports.

 

This was something I assembled for a challenge:

72t of payload (the jettisonable fuel tanks), launch mass 220t, for a payload faction of ~33%. I carry more engines and less wing area per weight.

[GoSlash27]

6 hours ago, foamyesque said:

What actually is the payload there, @GoSlash27? I don't see any cargo bays or docking ports.

The payload would be the fuel itself, had I finished out the design. It's just an example.

Best,
-Slashy

[TDplay]

On 5/9/2015 at 10:41 AM, GoSlash27 said:

Sure thing.

Mk3 spaceplanes follow the same rules as Mk2 spaceplanes. They're just scaled up.

Best,

-Slashy

Really? I tried simply scaling up my Mk2 designs, they won't even take off!

[AeroGav]

BRAAAIINNZZZ  !      Zombie thread warning !

This is fascinating though, how far we've come since then.    Has the community just got better at designing spaceplanes,  or is this the cumulative effect of small buffs, patch after patch?

[Wanderfound]

21 hours ago, TDplay said:

Really? I tried simply scaling up my Mk2 designs, they won't even take off!

Drag minimisation and heat tolerance matter a lot for Mk3 builds; you'll be spending a longer time accelerating in the thick air, so the heat has time to build. The less drag, the shorter that time will be.

You can do some things once you get it right, though:

 

 

 

 

15 hours ago, AeroGav said:

BRAAAIINNZZZ  !      Zombie thread warning !

This is fascinating though, how far we've come since then.    Has the community just got better at designing spaceplanes,  or is this the cumulative effect of small buffs, patch after patch?

It's a zombie, but it's interesting enough; may as well let it lurch.

Edited April 2, 2017 by Wanderfound

[TDplay]

1 minute ago, Wanderfound said:

It's a zombie, but it's interesting enough; may as well let it lurch.

Drag minimisation and heat tolerance matter a lot for Mk3 builds; you'll be spending a longer time accelerating in the thick air, so the heat has time to build. The less drag, the shorter that time will be.

You can do some things once you get it right, though:

[4 pics snipped]

The issue is, my SSTOs only get enough lift if it's a lifting body. I can get OPT J and K into orbit, but not the significantly smaller Mk3. The only exception is Mk1.

[Wanderfound]

20 minutes ago, TDplay said:

The issue is, my SSTOs only get enough lift if it's a lifting body. I can get OPT J and K into orbit, but not the significantly smaller Mk3. The only exception is Mk1.

Notice the lack of large wings on my examples?

Wing incidence matters a great deal; you want to set it so that the plane can climb while keeping the nose prograde, to minimise fuselage drag. And, as with the smaller planes, keep the weight down; no more engines than you need, don't carry too much ancillary junk (and hide it in a cargo bay if you do; drag is a killer).

If you can lift off at a reasonable speed (about 120m/s at the top end; lighter ships should manage it at 70m/s) and maintain altitude while accelerating, then you've probably got enough engine and wing.

As demonstrations, here's my standard Mk3 taking the cruisy route to orbit:

...and here's a lightly modified version of the same ship with the cargo capacity stretched to the limit.

 

Overall theme: you probably don't need as much wing, engine or intake as you think. And, if you're willing to take a bit of time on the initial climb, almost anything that you can get off the runway can eventually get up to speed and altitude.

Edited April 2, 2017 by Wanderfound

[TDplay]

24 minutes ago, Wanderfound said:

almost anything that you can get off the runway can eventually get up to speed and altitude.

Many crafts of mine do get off the runway, get into a promising horizontal takeoff, then they dive down, even if I hold 'S'.

27 minutes ago, Wanderfound said:

As demonstrations, here's my standard Mk3 taking the cruisy route to orbit:

Can that lift MKS Tundra 2.5m modules, I need an SSTO to lift new parts to my station, it desperately needs my advanced Life Support module, and I'd rather not waste rockets.

[Wanderfound]

24 minutes ago, TDplay said:

Many crafts of mine do get off the runway, get into a promising horizontal takeoff, then they dive down, even if I hold 'S'.

That suggests that you're lacking sufficient pitch control. Elevators and canards, as far from CoM as possible for maximum leverage. Keep the overall CoL fairly close behind CoM/dCoM.

OTOH, if you can hold the nose up but the plane descends anyway, then you may have a need for more wing or more engine. Or more delicate flying; with overweight marginal stuff, if you hold the nose too high during the early climb you'll generate so much drag that you can't accelerate. Get off the runway, lift the nose just enough to maintain level flight, build up a little bit of speed (i.e. 150-200m/s), then climb.

 

24 minutes ago, TDplay said:

Can that lift MKS Tundra 2.5m modules, I need an SSTO to lift new parts to my station, it desperately needs my advanced Life Support module, and I'd rather not waste rockets.

If it can fit in the bay (one standard long Mk3), it can lift it. The six-engine version can manage up to sixty tons, the eight-engine version eighty tons. You're unlikely to find a sensible payload that fits and weighs much more than forty, though; I had to pack the bay with ore tanks for the eighty ton test.

You can get a craft file for a six-engine version at https://kerbalx.com/Wanderfound/Kerbotruck-Compact-Lander 

Edited April 2, 2017 by Wanderfound

[Guest Space Cowboy]

My "best" Mk3 to date. Two orange tanks to 200Km with ease.

 

Download: https://lookaside.fbsbx.com/file/Master Race SSTO.craft?token=AWzt4xthnGXPdMjoHBfVCrJktD17Ost3fc26uLth0scRKCxMlNcsRRytunxR0wBlGfm5fxYURXziJJZDP4EE8NcFSEf6j85NG3BKqylQmb2NOO2ceiZXaGGAwbS4NnP9003DhZmH-xJIIGBwVQYr21ypUhc6ZuYSDQxzOf6Qn1c2LSdpL9XnAaXXIXnbprDoXlk

 

Edited April 2, 2017 by Space Cowboy

[TDplay]

13 hours ago, Space Cowboy said:

My "best" Mk3 to date. Two orange tanks to 200Km with ease.

 

Download: https://lookaside.fbsbx.com/file/Master Race SSTO.craft?token=AWzt4xthnGXPdMjoHBfVCrJktD17Ost3fc26uLth0scRKCxMlNcsRRytunxR0wBlGfm5fxYURXziJJZDP4EE8NcFSEf6j85NG3BKqylQmb2NOO2ceiZXaGGAwbS4NnP9003DhZmH-xJIIGBwVQYr21ypUhc6ZuYSDQxzOf6Qn1c2LSdpL9XnAaXXIXnbprDoXlk

[images snipped

That's very good! I find it hard to manage CoL and CoM when making long planes, so I build them wide instead.

[Guest Space Cowboy]

48 minutes ago, TDplay said:

That's very good! I find it hard to manage CoL and CoM when making long planes, so I build them wide instead.

Thank you. Yes indeed it can be difficult. I have been working on this type of desing awhile. This could be my 20th version I am not sure.

[eddiew]

On 01/04/2017 at 9:20 PM, AeroGav said:

This is fascinating though, how far we've come since then.    Has the community just got better at designing spaceplanes,  or is this the cumulative effect of small buffs, patch after patch?

I think it's largely aero updates, tbh. Used to be the general advice for wings was "as few as you can possibly get away with" where now, with them also being tanks, the added lift of doubling/tripling your wing area often leads to having more delta-v in orbit. Meanwhile I think jets and rapiers have taken a nerf since the old days... the new service ceilings are annoyingly low, but it force us to make things that can fly fast below 18km rather than starting our speed run at 25. That we end up making planes that look like terrestrial planes is a nod to the aero model being somewhat grounded in reality, even if much simplified. 

Not to mention the pre-1.0 days were really good at encouraging silly designs. We got used to flying flat-ended cylinders, where later versions insisted that things have at least some semblance of streamlining.

[KerikBalm]

1 hour ago, TDplay said:

That's very good! I find it hard to manage CoL and CoM when making long planes, so I build them wide instead.

I also build wide so that my payload can be wide.

^the payload is 3-kerbal eve descent and ascent vehicle capable of achieving orbit from eve-sea level, with full science package payload.

3.75m center stack + 2x.1.25m stacks + some doodads on the sides of the stacks, total diameter > 6.25m

I have made some more long and thin designs using mk3 bays instead of fairings.

Here's an example: 

The longest one I've made had 2x long cargobays and 1x medium cargobay, all inline.

More recently, I've been downsizing my mk3 sstos to make use of cargobays, and making deployable mobile bases with modules that individually fit within a single mk3 bay.

Initially like so:

And then using the kerbal planetary base systems mod:

On 4/1/2017 at 10:20 PM, AeroGav said:

BRAAAIINNZZZ  !      Zombie thread warning !

This is fascinating though, how far we've come since then.    Has the community just got better at designing spaceplanes,  or is this the cumulative effect of small buffs, patch after patch?

I don't know about the community as a whole, but in less than a week of 1.0 dropping, I had 200 ton to orbit mk3 designs:

They haven't really buffed anything since 1.0

Heating is less intense, but jet engines have had their Isps halved. When 1.0 dropped, rapiers go 6400 Isp, an Whiplashes got 8000 Isp. The atmosphere also produced less drag. My first SSTO design shown above had problems with the aeroshel overheating on ascent and exploding, which would detach the payload, but that was really the only problem I encountered when flying it.

I've cleaned up the design a bit from 1.02 to 1.04 to now, but the imrpovements weren't major

1.02 (the rear section ofthe payload was docked to complete the moho mission ship)

in 1.02, those big wings could handle the heat. In 1.04, they had to go:

Then I realized that I didnt' need the airbreaks, I could configure control surfaces to deflect opposite directions, I also realized I had more intakes than needed, and I could get by with less engines. Also the drag penalty of ending a 2.5m stack with a quadcoupler seemed to be less than tapering it to a 1.25m engines and adding 3 additional 1.25m stacks. I also increased the wing area, and got rid of a few control surfaces. Then since they added part autostrutting, I removed some struts. Even though its more draggy, I gave it a frontal 1.25m shielded docking port for utility

If I recall, the part count was just below 200 without payload, which was a significant reduction from earlier versions which had 250 to 300. I could remove all the little nosecones on the backs of the rapiers to reduce part count by 32. They don't really reduce drag all that much, and this design is not about super efficiency (not that its terrible), but its mainly about utility, it can lift a lot of payloads.

Pre-1.0, spaceplanes were ridiculously overpowered... you could get to orbital velocity on turbojets (before they were named whiplashes/turboramjets) alone, and their effective Isp could get to 40,000. By storing intake air, you could actually get to orbit on nothing but turbojets.

Getting to orbit on engines that could get up to 40,000 Isp... yea... pre 1.0 spaceplanes shouldn't be compared to post 1.0 spaceplanes

 

[TDplay]

2 minutes ago, KerikBalm said:

[snip]

So, looking at those, just strap tons of SSTO spaceplanes onto a core. and hope it works.

[KerikBalm]

Yes...

You joke, but you have no idea how right you are. I have made SSTOs doing exactly that

This is the same concept to the designs I posted earlier, which you jest are just SSTOs strapped onto a core, but with 1.25m and mk2 parts for earlier in career:

Now... the left and right do look rather like SSTOs in their own right, but clearly, they would need quite a bit of modification to work on their own.

That was an earlier version... the inline fairings were finicky, but after I got them to work:

Then I stuck a rocket at the back for better closed cycle performance... I occasionally try this on my bigger mk3 SSTOs as well, just redock the engine module after payload separation. I would omit that 3rd lv-t45 if I wanted to redock the mun lander, but hte mun lander was instead meant to redock to an orbiting fuel depot, and I had a dedicated tanker SSTO to fill that up (I only did 2 refueling missions that career before I switched to ISRU on Mun to supply it)

Docked to the impromptu Mun station (that needed more solar power and battery storage, which is why there is that stuff in front of the mun lander)

As to the concept you joked about.

Quote

 just strap tons of SSTO spaceplanes onto a core. and hope it works

I even developed mini "strap on" SSTOs to place on/around payloads to turn the whole thing into a SSTO. One does need to be somewhat careful about where you strap them to on the payload... generally you want the CoM to be the same as it was before you added the SSTOs... then you can be reasonably sure it will work if you added enough of them. One can figure out the payload capacity of one of the SSTOs, and just take your payload/SSTO payload to determine how many you need to strap on to it

The spaceplanes reenter separately

A modded electric fan plane meant for duna... a large wingspan means it wont fit in any reasonable payload space (folding wings would be awesome, but one cant practically do that in KSP)... strap on mini SSTOs and make it an SSTO

This reminded me of a shark... I should have done a single intake, rather than two, for greater efficiency... it was made when 1.0 was still recent, and I was learning to forget the old airhogging ways

A VTOL duna lander/spaceplane/rocketglider, wont SSTO from kerbin...

strap on spaceplanes:

Note, this one had to launch vertically, so I had some SRBs to help it liftoff - it pitched over to horizontal flight right away, and the SRBs decoupled and parachuted back onto the runway: technically not a SSTO, but still 100% launch vehicle recovery

 

Lets go even larger... back to the mk3 cargo and mobile base theme. Jets dont work on duna, so I made a rocket glider cargospaceplane for duna:

I'm almost certain it wouldn't have made it to kerbin orbit, even with a "drop tank" in the cargo bay (where the drop tank could reenter and recover on kerbin) because its dV and TWR budget was designed with Duna in mind (granted, its meant to carry a 40 ton payload from orbit to the surface, and back up to orbit without refueling - so maybe it could get to LKO). Instead, I strapped some SSTOs on to it, and it not only got to kerbin, but had enough dV in orbit to make the transfer to duna.

and.... with redesigned strap on SSTOs (those ones above were not very stable with those canards so far forward and empty tanks)

When I decoupled, the ones on the tip shot off pretty fast... should have taken a pic before decoupling:

the inner pair barely moved after decoupling:

 

So.... yes... one way to do it is just to make a compact SSTO with a lot of engine power, save it as a surface attachable sub assembly (requires some use of the re-root tool), and just strap them on to your payload as needed. If your payload needs wings, then these SSTOs are mostly just engine and fuel pods, with only enough wing area to land themselves when empty.... not to lift themselves and a payload when fully laden with fuel

Edited April 3, 2017 by KerikBalm

[TDplay]

23 hours ago, KerikBalm said:

[snip]

Ok, so I should take a mk3 core, and slap a million mk2 planes to it with struts and bob's yer uncle, mk3 spaceplane.

[KerikBalm]

They don't have to be mk2 planes... in my previous post, the only design that used mk3 parts didn't have a single mk2 part on it.

but in the end... its just about adding enough engines, fuel tanks, and wings. If you don't actually want all those engines/fuel tanks/wings once you reach orbit, then you might as well decouple them. If you're going to decouple, then you might as well decouple them in the form of a spaceplane that you can recover.

It can be one big spaceplane that decouples from the payload, or multiple smaller ones.

[Ajiko]

1.0.2 hard to SSTO's design, but it's possible.

Parameters that you need - at least 6000-8000 dV/0.8-0.9 TWR for atmosphere engines, at least 1600 dV/0.6-0.7 TWR for vacuum engines.

As a vacuum engines use Terriers or Poodles, as an atmosphere engines - RAPIER's or Whiplashes.

To break "sound barrier" on 320 m/s - you need 1 Whiplash/15 tonns of craft mass, if craft drag is acceptable.

[TDplay]

28 minutes ago, Ajiko said:

[in] 1.0.2 [it's] hard to [design] SSTO's design, but it's possible.

That was long ago

28 minutes ago, Ajiko said:

As a vacuum engines use Terriers or Poodles

More like LV-N 'Nerv' Atomic Rocket Motors and the R.A.P.I.E.R ClosedCycle to finish ascent!

30 minutes ago, Ajiko said:

as an atmospheric engines - RAPIERs or Whiplashes.

Or Panthers! You cannae forget panthers! Highest gimbal, effective for high altitude flight when control surfaces become useless.

33 minutes ago, Ajiko said:

To break [the] "sound barrier" on 320 m/s - you need 1 Whiplash/15 tonns of craft mass, if craft drag is acceptable

And what if I use Panther or R.A.P.I.E.R?

You're being very general here and yet over-specific too! Everyone here can build a mk2 SSTO, and you don't HAVE to use Whiplash engines to build an SSTO

[Ajiko]

2 minutes ago, TDplay said:

Or Panthers! You cannae forget panthers! Highest gimbal, effective for high altitude flight when control surfaces become useless.

We discuss 1.0.2, yes? Where is no Panthers.

In 1.0.2 RAPIER's not so effective as Whiplashes. +0,5 tonn, less Isp.

And you need to have one RAPIER for 12 tonnes of mass, to break 320 m/s.

[KerikBalm]

Well, 1.02 has faded from my memory, but I think this thread is mostly about sstos in general.

I don't bother with multiple engine types anymore. Rapiers can break the sound barrier just fine, every whiplash and every vacuum engine just adds extra mass and drag. The key performance factor is the speed and altitude when airbreathers cut out, and for that you want rapiers. I dont find a difference of 35-45 Isp to be worth adding extra engines - FYI, I would consider Aerospikes instead of the engines you mentioned, due to superior TWR, and thrust per cross sectional area. Or if you need a lot of thrust, a KR-2L. 340 Isp and 22.65 vacuum TWR

If I'm going to add a vacuum engine, its probably going to be LV-Ns. The rapiers can get me high and fast enough on closed cycle that if I need another 300 m/s, there will be time to do it with LV-Ns. Heck, you can do pretty high dV Liquid fuel Only designs without using any oxidizer. With LV-Ns for vacuum engines, you don't need to worry so much about getting the right LF-Oxidizer ratio.

No whiplashes, no poodles. LF heavy, but has oxidizer in orbit, remaining Oxidizer reduces the number of perapsis kicks needed, but when the Ox runs out, I can still maneuver in space, and when I bring it back, I can still cruise around on jets if I timed my deorbit wrong.

2 rapiers, 1 LV-N, gets to minmus and back no problem, 1x LV-N gives it good enough TWR for a craft that size

[TDplay]

9 minutes ago, Ajiko said:

We discuss 1.0.2, yes? Where is no Panthers.

In 1.0.2 RAPIER's not so effective as Whiplashes. +0,5 tonn, less Isp.

And you need to have one RAPIER for 12 tonnes of mass, to break 320 m/s.

Fair enough. Or as I'd say IRL, "Is it? OK."

5 minutes ago, KerikBalm said:

Well, 1.02 has faded from my memory, but I think this thread is mostly about sstos in general.

I don't bother with multiple engine types anymore. Rapiers can break the sound barrier just fine, every whiplash and every vacuum engine just adds extra mass and drag. The key performance factor is the speed and altitude when airbreathers cut out, and for that you want rapiers. I dont find a difference of 35-45 Isp to be worth adding extra engines - FYI, I would consider Aerospikes instead of the engines you mentioned, due to superior TWR, and thrust per cross sectional area. Or if you need a lot of thrust, a KR-2L. 340 Isp and 22.65 vacuum TWR

If I'm going to add a vacuum engine, its probably going to be LV-Ns. The rapiers can get me high and fast enough on closed cycle that if I need another 300 m/s, there will be time to do it with LV-Ns. Heck, you can do pretty high dV Liquid fuel Only designs without using any oxidizer. With LV-Ns for vacuum engines, you don't need to worry so much about getting the right LF-Oxidizer ratio.

No whiplashes, no poodles. LF heavy, but has oxidizer in orbit, remaining Oxidizer reduces the number of perapsis kicks needed, but when the Ox runs out, I can still maneuver in space, and when I bring it back, I can still cruise around on jets if I timed my deorbit wrong.

[pic snipped]

2 rapiers, 1 LV-N, gets to minmus and back no problem, 1x LV-N gives it good enough TWR for a craft that size

[pic snipped]

I don't remember 1.0.2 either, mostly because I never played it

Those are some nice crafts. How on earth do you land any SSTO on a planet with no atmo?

I always include a lander.

Edited April 4, 2017 by TDplay

[Ajiko]

 

25 minutes ago, KerikBalm said:

With LV-Ns for vacuum engines

In my opinion using LV-N's - extremely close to cheating.

But I agreed - with LV-N's you need to use RAPIER.

Edited April 4, 2017 by Ajiko