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Only flying boat I've done is this:

22686014009_b9fe7f8d9a_c.jpg
22456784783_ee44a4b8e7_c.jpg

Which is technically an amphibian, but seems happy on the water up to 100m/s or so ( not that it needs quite that much to take off ). I've thought about space flyingboats but not tried one yet ( I think I might resurrect my old HL cockpit first, it has a nice profile for sea stuff ).

Edited by Van Disaster

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[quote name='Van Disaster']Only flying boat I've done is this:

[url=https://flic.kr/p/AyFKAz][url]https://farm6.staticflickr.com/5681/22686014009_b9fe7f8d9a_c.jpg[/url][/url]
[url=https://flic.kr/p/AdqTJx][url]https://farm1.staticflickr.com/653/22456784783_ee44a4b8e7_c.jpg[/url][/url]

Which is technically an amphibian, but seems happy on the water up to 100m/s or so ( not that it needs quite that much to take off ). I've thought about space flyingboats but not tried one yet ( I think I might resurrect [URL="https://flic.kr/p/r4Se9x"]my old HL cockpit[/URL] first, it has a nice profile for sea stuff ).[/QUOTE]

Looks awesome! Craft?

My SSTO/Dropship/Mining Rig is nearly done.

It went from:
[spoiler=this][IMG]http://imgur.com/AawhW8T.jpg[/IMG][/spoiler]

To this:

[sketchfab]26c151dc6a7b4544baf81ec56f07ddc3[/sketchfab]

It reaches orbit effortlessly with a fair bit of lf/oxy left,
Im trying to reduce drag but FAR analysis tool randomly changing values doesn't help, sometimes it shows more lift less drag with landing gear out! :O Edited by RevanCorana

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[quote name='RevanCorana']Im trying to reduce drag but FAR analysis tool randomly changing values doesn't help, sometimes it shows more lift less drag with landing gear out! :O[/QUOTE]

Only pay attention to the stats with gear up, otherwise you end up optimising wave drag for the runway :) Dunno why you'd see more lift with the gear deployed though...

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[quote name='eddiew']Only pay attention to the stats with gear up, otherwise you end up optimising wave drag for the runway :) Dunno why you'd see more lift with the gear deployed though...[/QUOTE]

Yea thanks it's just a nasty bug with the graphs, restarting KSP fix it.
I'm debating if it really HAS to be an ssto...
With LF side droptanks it can save as much space in the cargo for another 4 oscar-B.

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[quote name='RevanCorana']Looks awesome! Craft?

Craft. B9 pWings which I know you have, but just in case anyone else wants it. I didn't really tune it at all, and the cargo bay is full of clipped nose pieces I used for experiments in shaping the hull for the water, but you can probably fit something in it still.

Today's effort: one airframe, two engine configs.
22614881923_4bdb0c2936_c.jpg
2.5M Supersonic version, 4x Whiplash

22847858337_bdae863c9c_c.jpg

5.0M Hypersonic, 6x Rapiers in airbreathing mode, 2x Whiplash. Rapiers don't overheat until around Mach 5, way above the Whiplash.

Not quite sure which is most fuel efficient tbh - both of them are horrible to get up to speed.

Edited by Van Disaster
hoping to fix broken formatting - folorn hope, I know.

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[quote name='Van Disaster'][URL="https://www.dropbox.com/s/lcifmjo4ihe4t35/Goose%20C4.1.craft?dl=0"]Craft[/URL]. B9 pWings which I know you have, but just in case anyone else wants it. I didn't really tune it at all, and the cargo bay is full of clipped nose pieces I used for experiments in shaping the hull for the water, but you can probably fit something in it still.

Today's effort: one airframe, two engine configs.
[url=https://flic.kr/p/Aspbvi][url]https://farm1.staticflickr.com/779/22614881923_4bdb0c2936_c.jpg[/url][/url]
2.5M Supersonic version, 4x Whiplash

[url=https://flic.kr/p/ANZfh2][url]https://farm6.staticflickr.com/5648/22847858337_bdae863c9c_c.jpg[/url][/url]

5.0M Hypersonic, 6x Rapiers in airbreathing mode, 2x Whiplash. Rapiers don't overheat until around Mach 5, way above the Whiplash.

Not quite sure which is most fuel efficient tbh - both of them are horrible to get up to speed.[/QUOTE]
Nice! but a bit too wobbly on the tail lol (that name tho).

Are those ram intakes? Replacing them with spikes might add just the extra air needed to remove a couple of engines.

[IMG]http://i.imgur.com/x5B4rzO.png[/IMG]

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They're B9 radial intakes with stock diverterless intakes stuck on the back afterwards in an attempt to manage heat. Air isn't a problem, it's the thrust profiles. Solved for the supersonic one by adding a pair of Panthers with the gimballing off, but I really don't want to add *more* engines to the hypersonic. Going to try converting a tank to LO/LF I guess.

Eh, the flyingboat tail is a bit wobbly occasionally but it works just fine as a tail :P Edited by Van Disaster

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[video=youtube_share;ji7AV2D3anY]http://youtu.be/ji7AV2D3anY[/video]

Craft file at [URL]https://www.dropbox.com/s/xlh3xh4hy197xx5/Kerbodyne%20Demo%201.craft?dl=0[/URL]

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Hmm seems the wiplash will is more efficient but has a lower top speed.
Maybe the rapier can be more efficient for long trips.

The SSTO I've been working which uses a single rapier used to either explode due to heat or not exceed 15km high lol.
Since rapier requires precise trajectories, fixed it by improving the handling so that the trajectories become easier and faster to correct therefore wasting less acceleration both maneuvers and oscillations.

Can see the advanced canard which also has some aoa control to increase L/D

[IMG]http://imgur.com/G8e4Nrr.jpg[/IMG]

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My single rapier SSTO plane works nicely provided you keep to a specific climb trajectory - if you go too high too fast then it'll flop down the back of the TWR curve & you'll have to pull such high AoA you'll never have the thrust to recover past the extra drag. Having a decent amount of wing helps.
22779527327_a61cf26382_z.jpg

Biggest problem is re-entry & not cooking the cockpit.

Fixed the hypersonic airliner by switching some tankage to LF/O, and using one pair of engines in rocket mode when the Whiplash pair start overheating - that boosts it to about M3.2 & 20km, and then it'll just meander up to final cruise height. At 27km/M5.0 it's burning less fuel than the supersonic version, problem is it uses half it's fuel just to get there... interesting design puzzle this is being. I suspect given the horrible economy of a rocket motor I might be better off adding more jets instead.
23250990386_453444449e_c.jpg

( not fully loaded on takeoff, the tail is an empty tank so I can pump fuel in it to trim when supersonic ).

Edited by Van Disaster

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[quote name='Van Disaster']My single rapier SSTO plane works nicely provided you keep to a specific climb trajectory - if you go too high too fast then it'll flop down the back of the TWR curve & you'll have to pull such high AoA you'll never have the thrust to recover past the extra drag. Having a decent amount of wing helps.
[url=https://flic.kr/p/AGX2Ra][url]https://farm1.staticflickr.com/694/22779527327_a61cf26382_z.jpg[/url][/url]

Biggest problem is re-entry & not cooking the cockpit.

Fixed the hypersonic airliner by switching some tankage to LF/O, and using one pair of engines in rocket mode when the Whiplash pair start overheating - that boosts it to about M3.2 & 20km, and then it'll just meander up to final cruise height. At 27km/M5.0 it's burning less fuel than the supersonic version, problem is it uses half it's fuel just to get there... interesting design puzzle this is being. I suspect given the horrible economy of a rocket motor I might be better off adding more jets instead.
[url=https://flic.kr/p/BqBpoA][url]https://farm1.staticflickr.com/747/23250990386_453444449e_c.jpg[/url][/url]

( not fully loaded on takeoff, the tail is an empty tank so I can pump fuel in it to trim when supersonic ).[/QUOTE]


I have actually fixed most of my heating issues with the engines by using radiators set near the engine connection points.
[img]http://i.imgur.com/CnW4zbM.jpg[/img]
You can see them glowing here.

The fuel load issue, is a really rough one due to the types of engines being used. I found if you actually reduce the number of engines, it will accelerate slower but will still reach the desired speeds at some altitudes if the wave drag is low enough. The altitude you are trying to reach is really the issue. 27km is quite high for most airbreathers on Kerbin. But it is a very impressive airliner.

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Yeah, I have radiators on the intakes - attaching them right to the engine doesn't seem to make any difference. The problem with less engines is the fuel burn per km - it seems more efficient to have extra engines & shut them down ( or in this case run them all throttled well back - that helps with heat too ) but get to economical altitudes faster, than claw your way up at bare minimum thrust - this is the biggest problem with Rapiers, it'd be fixed if we had a model of a Reaction Engines Scimitar ( sure I've seen one but no idea where ). A lot of this experimentation is going to help spaceplane design, of course... and this'd be a much more sensible craft for RSS or 64x because by the time you've got it settled at altitude it's 10 mins away from descent :P

I just left it at a suitable pitch & let it settle on an altitude - less pitch means less drag of course, but it'll also settle at higher dynamic pressure which brings drag back up so in the end nothing much changed. Wave drag area is about 5m^2, not really much I can do to bring that down without a complete redesign. Edited by Van Disaster

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@Wanderfound
There's something very rewarding about making a functional plane with the entry-level parts. Mine are rather more shambolic than yours, but I'll post them later. I actually built a sort of MiG-105-esque orbiter for 3 Kerbals and it survives re-entry, miraculously, though it flies like a brick.

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Let me brake silence in this thread and show you my first successful SSTOs: New Brunswick (on the picture to the left) and his elder brother Nova Scotia (to the right). Both capable of flying to low orbit and back without any problems and without even a single roll over.
Nova Scotia was the first of the two, and originally it meant to be a recreation of Skylone, but I quickly found out that for some reason the exact copy of real-life project won't work in KSP, so I went on making it flyable. The result was huge 160 parts 250 tons beasty with payload bay so huge you could place a Shuttle there (well, at least the fuselage without wings). It flew pretty well though, but was a little slow on response and quiet bulky overall. So I made a copy - New Brunswick - smaller and better and this I really love.

 

 

Edited by Paul_Sawyer

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Nice ssto!

Daedalus might get yaw control finally as it makes it much better at .. flying

Craft not ready just yet sry

 

Edited by RevanCorana

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I haven't created something worth to show for quite a long time. Latest B9 Aerospace mod release for KSP 1.0.5. is deserved my attention.
So, here is something to celebrate B9 Aerospace release.
liv5qi2.jpg

It is still WIP craft, but already made first successful test flight to LKO with 72 t of payload (two orange tanks). Small payload compared for craft of similar size and shape that I created for KSP 0.90 (367,4t), but hey, a lot was changed since then in this game. This time, I wanted to create more aestetic craft with less payload weight, but I doubt that I will need more weight than 2 orange tanks at once, so this craft will serve it's purpose. This one is not only better looking craft, but much less engines were needed for brute force power to bring this one into space.

Craft file will be available soon in thread linked in signature, but I want to made some more optimization before publishing. Need to unload extra oxydizer that could not be used due to lack of fuel spent on airbreathing engine mode and fix for torque problems in space and provide flight instructions for maximum efficiency.

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Anyone got any tips for curing a dynamical roll instability, I *think* it's "Dutch Roll"?

This is the troubled spaceplane

https://flic.kr/p/Cm5LRx

I eventually got all derivs to be green in the relevant flight regimes, but the dynamic simulation shows divergence in a lateral sim and the plane is prone to a nasty roll oscillation at high speeds and altitudes. It seems to be worsened when I'm putting a big pitch-up input.

A significant constraint on the design is it's going to be a shuttle orbiter, and I was planning on putting the ET "above" rather than "below" the orbiter. (Because it has a downards-opening cargo bay to deposit payloads on places like Laythe). That means I can't have a large central tailfin, and even with the twin-tail I'm mindful that I don't want them to be too high.

Edited by cantab
Deleted second question, reasked that back in the FAR thread

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11 hours ago, cantab said:

Anyone got any tips for curing a dynamical roll instability, I *think* it's "Dutch Roll"?

This is the troubled spaceplane

https://flic.kr/p/Cm5LRx

I eventually got all derivs to be green in the relevant flight regimes, but the dynamic simulation shows divergence in a lateral sim and the plane is prone to a nasty roll oscillation at high speeds and altitudes. It seems to be worsened when I'm putting a big pitch-up input.

A significant constraint on the design is it's going to be a shuttle orbiter, and I was planning on putting the ET "above" rather than "below" the orbiter. (Because it has a downards-opening cargo bay to deposit payloads on places like Laythe). That means I can't have a large central tailfin, and even with the twin-tail I'm mindful that I don't want them to be too high.

Somewhat relatedly, did the wing leveller function change recently or am I just using it wrong? It now seems very bad at levelling the wings.


something like this?
i used tweakscale to make the basic fin double size
Jlq8rnw.png
 

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15 hours ago, Wanderfound said:

Considered a ventral tailfin that you decouple just before landing? It's worked in reality...

https://en.m.wikipedia.org/wiki/North_American_X-15

Well I want to take off again afterwards. it's a pretty ambitious plan I'm working on I know. That said there's some room for a fixed ventral fin. I did though have issues with tailfins below the centre of mass sending the L-Beta derivative wrong and destabilising the plane in roll. (I think I understand this intuitively, by considering the lift the tailfin generates when sideslipping and how that affects the plane's roll.) But maybe it's something I can control.

4 hours ago, SimGuLiM said:


something like this?
i used tweakscale to make the basic fin double size
Jlq8rnw.png
 

That would be the easy way, but it's exactly what I don't want to do. Though I suppose it's *possible* if I mount the shuttle stack below the orbiter like "normal".

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@cantab analyzing your craft I have noticed some  things that may be important.
First is that you have way too much dihedral effect, your wings have a big sweep angle and are above the center of mass, I recommend sweeping them less as that is affected more by speed, moving them lower or angling them down would only solve the instability for slower speeds, where you don't seem to be having problems.
Then, you are going to need more vertical stabilization, if you cannot make your vertical stabilizers higher the only option left is making them longer, and further back from the center of mass.
In fact, you may want to extend those vertical stabilizers a bit far behind the craft, making it behave like a lawn dart on the yaw axis.
If you are going to keep the sweep angle as it is, I heavily recommend changing that nose, blunt noses are only good for on hypersonic to bend the shockwave, which would not matter much in this case, go for something more pointy.

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