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Scifi SR-71

Posted: 2020-05-15 06:59pm
by Grahf: Seeker Of Power
So this is the Starblade, a scifi style SR-71. It is not only used for strategic recon but also as a deep operations warfare ship, like deploying special forces squads and hitting important targets. Its about 100m long.

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It has a large railgun mounted conformal to the central structure:

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However, if the need arises the weapon can be deployed and rotated 360 degrees and elevate/depress a good bit also:

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Re: Scifi SR-71

Posted: 2020-05-15 09:10pm
by Starglider
I don't understand the seemingly random mix of streamlined and unstreamlined parts.

Re: Scifi SR-71

Posted: 2020-05-17 08:48pm
by The_Saint
Starglider wrote:
2020-05-15 09:10pm
I don't understand the seemingly random mix of streamlined and unstreamlined parts.
I'm with Starglider here.
To the naked untrained eye it looks pretty reasonable for layout but on closer inspection by the barely/half trained eye there's a lot of little problems.

The forward fuselage chines show good shape blending (particularly for a high mach number craft), the engine intakes have an interesting but good blended shape but then there's hard right angles in places that could (should?) be blended and lots of lovely greeblies that ruin the airflow.

Some suggestions:
Smooth over the greeblies on the front fuselage, lose the ribs along side the engine nacelles (if you need that kind of reinforcing to move at high speed then you're already not going to achieve the speed that the overall shape suggests).

Lose the wing guns, or move them up to where the wing meets the body and get a more aerodynamic fairing. Something like the lerxs on a hornet or flanker.
The top turret probably either needs to be retractable or a more streamlined fairing to fit in with the overall scheme.

I hope there's some kind of sci fi hovering capability to land to enable deployment of the special forces squad or they'll probably have to air drop at speed??
From a structural perspective I'm not sure what's going to happen when you fire a railgun of that apparent calibre in any direction than along the centreline but it'll probably require materials science beyond anything current to prevent some spectacular deconstruction (not too mention handling effects).

Re: Scifi SR-71

Posted: 2020-05-17 10:59pm
by Grahf: Seeker Of Power
Uh, its a spaceship my friends. I probably should have clarified that in the first place. The ribs on the front are the RCS thrusters. The railgun is not actually that large a caliber, around 180mm. The perspective skews the actual dimensions of the gun. Mixing geometric and "organic" detail is part of my overall design style. I like the contrast between the two perspectives.

Re: Scifi SR-71

Posted: 2020-05-18 12:28am
by The_Saint
RCS at the front makes a lot more sense and certainly space is more forgiving on cleanliness of hull. Thought, the vertical stabilisers would have a pretty weak structural join, not to mention a possible maintenance nightmare mounted directly over the engine nacelle, suggestion move the stabilisers either inboard or outboard. I'd be tempted to go outboard and move the engine nozzles closer to the centreline so if there's an engine out there's less yaw problems.

Depending on what kind of science might be going on here ... you might find 180mm to be a tad more than "not actually that large a calibre" when it comes to railguns. Being in space (and future tech) might grant some free passes but no one wants to end up with The Last Jedi Mandator IV silliness again.

Depending on what kind of flight dynamics are in this setting (RCS suggests something close to realistic) firing the railgun off axis might either be a bad physics idea or a bad tactical idea. I think I'd almost expect the ship to rotate so that it faces the threat, to fire it's railgun, so that it presents the smallest silhouette.

Please don't take any of this as negative criticism (I'd like to think it's constructive criticism), overall I like the design. Particularly the engine nacelle features.

Re: Scifi SR-71

Posted: 2020-05-20 04:59am
by Starglider
If it's a pure spacecraft then there's no reason for it to be streamlined or have aircraft style fins in the first place. This shape comes with substantial mass, maneuverability, cost and durability penalties compared to a more blocky shape with less surface area and angular momentum. Star Trek gets away with this by saying some kind of shaping (not conventional aerodynamic streamlining) is necessary for 'warp geometry' i.e. FTL magic.

Re: Scifi SR-71

Posted: 2020-05-20 08:43am
by Tribble
Starglider wrote:
2020-05-20 04:59am
If it's a pure spacecraft then there's no reason for it to be streamlined or have aircraft style fins in the first place. This shape comes with substantial mass, maneuverability, cost and durability penalties compared to a more blocky shape with less surface area and angular momentum. Star Trek gets away with this by saying some kind of shaping (not conventional aerodynamic streamlining) is necessary for 'warp geometry' i.e. FTL magic.
Well, one of the fastest ships in the franchise is literally a giant Cube (even without using transwarp it can easily outrun a Galaxy Class). So it’s not like warp geometry matters that much to starship design in Trek, at least if you’re advanced enough :P

Re: Scifi SR-71

Posted: 2020-05-20 02:48pm
by Starglider
Tribble wrote:
2020-05-20 08:43am
Well, one of the fastest ships in the franchise is literally a giant Cube (even without using transwarp it can easily outrun a Galaxy Class). So it’s not like warp geometry matters that much to starship design in Trek, at least if you’re advanced enough :P
That always struck me as part of the intimidation factor of the Borg, they can just ignore constraints that apply to everyone else. Of course that theme was toned down a lot in Voyager, where one scout ship regularly blew up Borg cubes (by the dozen, towards the end). Trek also had the idea that the drive nacelles were dangerous and needed to be kept away from the main hull: relatively uncommon, most space opera goes with 'the FTL widget is a compact machine buried in the middle of the ship'.

Re: Scifi SR-71

Posted: 2020-05-21 12:45am
by Grahf: Seeker Of Power
I'm not particularly concerned with realism...I wanted a SR-71 style spaceship. With guns......and guns.

Re: Scifi SR-71

Posted: 2020-05-21 02:50pm
by Beowulf
Bearing in mind it's a spaceship, and it's stylized...

I'm not quite sure I see the point of the railgun mount. There's an open tube for it to shoot through, but it's also on a turret. I think it'd probably be more sensible if either the non-moving structure in front of the rail gun wasn't there, or if instead of just having an open tube, had it either enclosed (hides the gun, but needs the gun to be raised to fire), or had a door that opened for firing when the gun isn't raised).

Also, given the streamlined style, I don't get the ribs/etc facing perpendicular to the flow.

Re: Scifi SR-71

Posted: 2020-05-21 10:12pm
by Grahf: Seeker Of Power
Those, according to Lord Adorable, are a set of fabulous buttresses.