Kerbodyne SSTO Division: Omnibus Thread

[Hodo]

Yeah, the plane I tried was a bit like that - twin engine rear-delta wing. Which don't feel like a terrible idea. Clearly there is much to learn about nuFAR - maybe it'll be pushing us towards mid wing conventional shapes?

This design has some problems I am working out, but I think I am close to getting this craft to working exactly the way I want it to. Been doing some research on real life delta-wing aircraft and finding some design flaws that have been corrected with real world solutions that would work in NuFAR. This makes me very happy.

Down sides of the delta currently in NuFAR is it is a bit twitchy and unstable at low speeds, but a dream at supersonic speeds. So it maybe the thing to have for SSTOs but it is by far not the only choice. I think as I experiment more I may go back to my cranked arrow delta wing designs.

Edited May 7, 2015 by Hodo

[Jovus]

Been doing some research on real life delta-wing aircraft and finding some design flaws that have been corrected with real world solutions that would work in NuFAR. This makes me very happy.

Well?! You can't just say stuff like that without sharing!

[Hodo]

Well?! You can't just say stuff like that without sharing!

Well it started here...

http://en.wikipedia.org/wiki/Delta_wing

Where I was reading about real life problems with the delta wing design, and how some engineers overcame it. Then I went to several different resources and looked over how they came up with solutions and why.

Like why the Su-17 uses a cranked delta design in its tailed delta wing craft. It is really exciting and interesting stuff, that with NuFAR works.

[eddiew]

Does anyone else prefer their planes to look kinda short and stubby?

- ascend at 45 degrees and hope for 1200m/s before flameout. AP should be > 65km on air. I'm not actually sure the wings do anything except act as anchors for control surfaces... might reduce them to small deltas and see if it still flies

4x turbos, 2x nervas, carries a T200+T400 tank to LKO. No oxidiser except in the cargo bay

*edit* It's much prettier this morning but I forgot to take screenshots

Edited May 8, 2015 by eddiew

[funk]

Hey guys, can anyone explain to me what's the new behaviour of the intakes? Is the old build rule still valid? I've recognized some weird behaviour, it seems like the attaching rule has changed vice versa - engine-intake engine-intake?

I think people just imagine high speed and futuristic planes to have delta wings... visually, they look sleeker, because it feels right that the pointy end goes first :> But on the whole, I have found midwing+tail to be more controllable. And I have tried many delta wing shapes throughout 0.90

It's nothing about future or past, it's just about aerodynamics. At supersonic and hypersonic speeds you want extremly sharp wings, even negative sharped wings are imaginable, or just a lifting body with some control. But planes in such a shape are hardly maneuverable at subsonic speeds. IR they try to combine the different approaches, which leads mostly to multiple delta wings or in some cases to jackknife wings. If you try to design the same way, it should be possible to get some stable delta wing shaped planes. I've build dozens in 0.90 with FAR. In the following thread I'd already explained something about them: http://forum.kerbalspaceprogram.com/threads/115600-RO-and-spaceplanes?p=1840878#post1840878

The only thing I'm guessing is, if nuFAR, with its voxel approach, recognizes the shape of e.g. the leading edge? This could be an opener to many more designs...

[Hodo]

And yes the NuFAR does take all of that into account to some degree. I flew this nearly finale version of the craft I posted before. It is amazingly stable now and easy to fly.

NuFAR is amazing so far, cant wait till it is finally released.

[peachoftree]

https://github.com/ferram4/Ferram-Aerospace-Research/pull/64

It's happening.

Oh. My. God. Its here. Rejoice in all its glory

[Hodo]

Oh. My. God. Its here. Rejoice in all its glory

Is it bad I am more excited about that then KSP updating to 1.0?

[eddiew]

Probably the last time I'll build anything with just nukes and turbojets for 1.0.2 stock aero. It's just too much to ask, you can't really get a decent trajectory out of the turbos, and you burn all your fuel circularizing on desperately low thrust. Might refit for a pair of 45s and fill the oxidiser sections.

Still, kinda got it's own aesthetic going and at least it did actually manage a polar orbit - which turns out to be way harder than equatorial!

Edited May 9, 2015 by eddiew

[peachoftree]

Is it bad I am more excited about that then KSP updating to 1.0?

Nope, I feel the same way. Unless were both insane:0.0:

[eddiew]

Let's see you do this in nuFAR ¬_¬

And since we all know Wanderfound hates boring rear-wing builds...

- nuStock (good) and nuFAR (scary ride!)

- nuStock only.

- only needed some minor tweaks to the tail. Bit rolly on the ascent and the CoL is dangerously close to the CoM, but it's controllable. Re-entry is surprisingly easy; those air brakes seem to be OP in nuFAR as well as stock... not sure if they have an artificial drag factor beyond their shape and size.

Edited May 9, 2015 by eddiew

[eddiew]

So I played a bit with minimalism in nuFAR...

Capable of an AP outside the atmosphere on air, if taken up at 45 degress. Best ascent seems to be around 30 with a 60km AP. Nerv gets pretty hot while circularizing, but just makes it with 700m/s left. Enough room for a micro-probe. LF tank clipped inside, justified by removing all oxidiser (this should be an option now let's face it).

Interestingly, it did better with the canards than without. I'd expected increased drag, but the extra lift meant a shallower AoA, and actually reduced drag overall. Interesting thing to consider, never thought about that before

First time I've seen a 5.5 TWR on air xD

Edited May 10, 2015 by eddiew

[Wanderfound]

NuFAR certainly encourages vigorous Q levels at low altitude...

[Wanderfound]

...and the new Dynamic Deflection mod (http://forum.kerbalspaceprogram.com/threads/116888-1-0-The-Plugin-Workshop-Small-plugins-of-varied-function) makes sustained high-G craziness a breeze, too:

(OTOH, triggering the spoilers to try and tighten the turn did not end well...)

[eddiew]

Lol, that just looks dangerous xD Does it not overheat and kersplode? Also I'm confused how you made those wings work; the swept ones with pointy tips caused immense drag for me, that's why I resorted to a delta wing :S

[Wanderfound]

I'm planning on reviving the race series: take off, loop, through the tight mountain passes then back to KSC. Get some practice in.

Area ruling doesn't need to be perfect when the total area is so low. It gets a smidgeon toasty, but so long as you throttle down occasionally it's fine.

Until you activate the spoilers...

[Kagame]

Okay, I finally made a Mk. 3 SSTO I can be (somewhat) proud of!

(nuStock)

(Yes, that's the way it unpacks. Makes for a comparatively short takeoff roll at least...)

I call it the Space Vannana, for space van-bannana. Able to lift two ion probes and one science lab at the same time- barely. And -barely- deorbit. Much more capable if only one of the cargo categories is used at the same time. I do wish I had Eddie's "problem" of excess thrust...

At least it claims the record for least eventful re-entry. Seriously. None of the flame FX played- actually, I don't think ANY aero FX were harmed during re-entry. Then again, I did pop chutes and deploy airbrakes as soon as I dipped below 60,000...

[Wanderfound]

Time for a race: http://forum.kerbalspaceprogram.com/threads/120751-Kerbodyne-Race-Series-Redux-Race-1

[Wanderfound]

First up for the nuFAR range: Kerbodyne Queequeg. Chase your space whale.

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Craft file at https://www.dropbox.com/s/r2e9iw79kwnaamk/Kerbodyne%20Queequeg.craft?dl=0

[eddiew]

First up for the nuFAR range: Kerbodyne Queequeg. Chase your space whale.

First impressions, it's quite... long. I guess that's what nuFAR will push us towards now - but it's nice to see a healthy bit of spare fuel in LKO. Pretty much everything I make under stock has ~200m/s tops, and no chance of carrying a bigger cargo. Not sure I like that you can get an out-of-atmosphere apoapsis on air though (see Dagger above)...

Oh, and what with LV-Ns only requiring fuel now, you might be interested to know that procedural tanks is up to date for 1.0.2: http://forum.kerbalspaceprogram.com/threads/106975-0-90-Procedural-Parts-Parts-the-way-you-want-em-v1-0-Jan-11 Interesting potential and fine tuning (and fuel selection), though no mk2 parts, sadly.

[Wanderfound]

You can make 'em shorter, but only if you add some lateral tanks; the long fuselage on the Queequeg was for fuel storage rather than aerodynamic reasons. But as soon as you go beyond single-fuselage, you've got a lot more drag to worry about...

[Wanderfound]

Not sure I like that you can get an out-of-atmosphere apoapsis on air though (see Dagger above)...

You can, but you shouldn't; it's much more fuel efficient to use a flatter approach. If you keep the Queequeg in a vertical climb, it'll boost the Ap to 80km or so on pure jet, but you'll empty the oxidiser tanks trying to circularise it.

OTOH, a pure turbojet suborbital tourist ship is now feasible.

[eddiew]

Tbh, I was quite impressed at the speed you got out of your rapiers on air - don't think I've ever gotten better than 1200. My worry is that a flat ascent leaves you in relatively thick air at 24km when your jets give up and creates heat issues; but I haven't yet tried that flight profile under nuFAR. Is the heating less ferocious than stock?

I took Dagger to an aggressive apoapsis because the LV-N is only 0.43 TWR when lit, and there's no oxidiser onboard; lighting the nerva at 20km and keeping the nose up can push it to around 110km, just enough breathing room to get into orbit. Not sure it would make it any other way... Circularizes with about 650m/s in the tank, without a cargo. Fun experiment, probably not useful for more than tourism.

[Wanderfound]

Tbh, I was quite impressed at the speed you got out of your rapiers on air - don't think I've ever gotten better than 1200. My worry is that a flat ascent leaves you in relatively thick air at 24km when your jets give up and creates heat issues; but I haven't yet tried that flight profile under nuFAR. Is the heating less ferocious than stock?

I took Dagger to an aggressive apoapsis because the LV-N is only 0.43 TWR when lit, and there's no oxidiser onboard; lighting the nerva at 20km and keeping the nose up can push it to around 110km, just enough breathing room to get into orbit. Not sure it would make it any other way... Circularizes with about 650m/s in the tank, without a cargo. Fun experiment, probably not useful for more than tourism.

You do need to balance the heat; steep climb to start, level off such that you get flattish before the RAPIERs flick over. The low drag design helps, too; friction means heat.

I'll have a bash at a turbo/nuke pure LF design next; I think it should work well so long as you can keep the wave drag down. What sort of drag areas are you getting? Queequeg is at 0.8m² wave drag from 5m² cross section.

[eddiew]

...I'll have to check that after work tonight I did cheat quite a lot with tucking the nacelles into the sides and a hidden LF tank, but in my mind that's sort of made up for by the absence of oxidiser. Then again, maybe a few units just to give maybe 5-10 seconds on rapier rockets, might actually work favourably. Something to experiment with I think ^^

Be interested to see some early-career turbonuke nuFAR options. It's just about doable under stock, but since it's basically mandatory to get your AP up to the fringe of space, you have to go up so steep that you lose a lot of speed to gravity. I refitted my Ballistic to T45s instead of nervas and ended up with about the same amount of delta-v in LKO (jack), and a lot less stress during the ascent. Might well work with 909s too; same thrust as the nervas, but 4T lighter overall could swing the balance.