Project LR1 Skyhammer: A New Shuttle [p1]

[NextBigLeap]

Great project, looks like the successor to the Starclipper addon. Cant wait!

 

[Pipcard]

40 tonnes is still a lot of payload for a mostly-reusable launch vehicle.

 

[Donamy]

Would this be about right ?

 

[kocmolyf]

Would this be about right ?

Close but not quite. I don't have my primary computer handy at the moment to do a proper scaling, but Skyhammer is a bit larger than the Shuttle. It's 46.4 m from its nose to its elevon tips, and the main body is 17.7 m wide with the fin tips reaching out to 31.9 m.

 

[dacamp66]

what is your opinion about articulating the fins (basically the fins hinge outboard at the base of the fin after reentry to turn them into wings), also, the speed brakes/elevons would function as drag rudders (ala B-2 bomber) also known as book rudders? for roll and pitch control, the top and bottom halves act in unison (both halves going up or down as necessary) for yaw control both halves act in opposition (E.G. to turn left, right elevon stays shut, left elevon top goes up, left elevon bottom goes down, thus generating differential drag (more drag left of central longitudinal axis than on right, etc., etc. this might allow a slower landing speed.

 

[kocmolyf]

what is your opinion about articulating the fins (basically the fins hinge outboard at the base of the fin after reentry to turn them into wings)...?

It's an interesting idea. The fins actually already generate quite a bit of the subsonic lift in this configuration. The main problem with rotating them to horizontal is that they cease to be vertical stabilizers. The delta body shape has large inherent yaw instabilities, which is why most of them have these kinds of prominent fins. Their current orientation is a pretty good compromise between subsonic lift and yaw stability.

The original STAR Clipper had swing wings to help reduce landing speed. By the time of Shuttle though, enough lifting body data had been gathered that we were comfortable with low-lift landings. So ultimately, I think that variable shapes are more trouble and weight than they are worth.

 

[kocmolyf]

Well, I've knocked everything off of my "initial exterior model complete" list. Next step will be setting up a build environment and getting this thing into its first flight!

Here's what it looks like right now:

Current launch configuration.

Forward RCS.

Aft RCS.

Ortho top.

Ortho bottom.

Ortho front.

Ortho aft.

Ortho left.

---------- Post added 08-29-14 at 02:40 AM ---------- Previous post was 08-28-14 at 06:14 AM ----------

I see no one caught on to the fact that I blatantly forgot the +Z nose thrusters.

 

[n0mad23]

Man I love the form of this. The profile from top and bottom really have an almost organic/life form quality in terms of function/form. Like a penguin evolved for swimming at several times the speed of sound. I love it when advanced engineering results in bio-mimicry. I'd say you're on to something really special. :thumbup:

 

[Andy44]

Are the external tanks coated with foam insulation? If so, is there adequate protection for the leading edges of the tail fins, given what we know in hindsight post-Columbia? Just askin...not sure how much insulation you need with this propellant vice LH2.

 

[Loru]

I don't see big SRBs here so problem of falling foam would be greatly reduced in this concept. AFAIK most of foam falling off from ET was caused by SRB induced vibrations.

 

[MaverickSawyer]

I don't see big SRBs here so problem of falling foam would be greatly reduced in this concept. AFAIK most of foam falling off from ET was caused by SRB induced vibrations.

I think that there was an aerodynamic component to the loss as well, but I'm not positive.

As for the insulation... LOX and CH4(l) are both soft cryogenic, so you shouldn't need it quite so badly.

This is turning into an amazingly sexy ship. Can't wait to take it for a spin!

 

[kocmolyf]

Are the external tanks coated with foam insulation?

I gave the tanks an orange-ish color while defining the shape, but I didn't intend that they were covered in ET foam. This problem was actually one of the first things I researched before deciding to go with the forward drop tanks - it turns out if you use sandwich panel insulation, you can pretty much avoid it.

 

[MaverickSawyer]

I gave the tanks an orange-ish color while defining the shape, but I didn't intend that they were covered in ET foam. This problem was actually one of the first things I researched before deciding to go with the forward drop tanks - it turns out if you use sandwich panel insulation, you can pretty much avoid it.

Hrm... helium filled fiberglass honeycomb? IIRC, they used that on the shared tank wall of the S-IV stages of the Saturn I and V rockets...

 

[kocmolyf]

Hrm... helium filled fiberglass honeycomb?

There are several options; some of them are evacuated with inert gas (as above), others fill the honeycomb with an insulating foam, but they're all variants on a theme. The main point is that the insulating agent is contained within the sandwich structure rather than able to detach from the exterior and cause problems.

---------- Post added at 11:30 PM ---------- Previous post was at 06:35 PM ----------

Upon exporting to Orbiter, all the normals in the mesh were completely hosed. I managed to clean up most of them with some hackery, but I need to go scrub the mesh again and do it cleanly. Normals or not, the mesh is in-game, which means I can make it fly! Special thanks to vlad32768 for the export script and Hlynkacg for the "hack your way to a module" tutorial. Now that I understand all the links in the chain, I can go back and do it correctly.

In the mean time, I'd like to get your feedback on what you'd like to see implemented first. My rough plan is:

1. Ascent (main propulsion, gimbal control, outer engine shutdown, staging)
2. Final approach (subsonic aerodynamics, aerosurfaces, landing gear, related damage)
3. Orbital maneuvering (orbital propulsion, RCS)
4. Entry (hypersonic aerodynamics, heating)
5. Interior (VC)
6. Payload operations (payload bay, robotic arm)
7. Internal systems (propellants, coolants, electrical system, etc.)

I plan to release each step as I complete it so I can collect feedback on an ongoing basis.

 

[PhantomCruiser]

Your plan of attack looks pretty sound.

Do you have anything in mind for an ascent autopilot? Or will it be mad pilot skills only?
And, will you have it compatible with autoFCS for recovery?

Nice work so far, two thumbs up from me!

 

[kocmolyf]

Do you have anything in mind for an ascent autopilot? Or will it be mad pilot skills only?

I was at least planning on doing a HUD aid, but it turns out you basically need an autopilot for that anyway, so probably yes.

And, will you have it compatible with autoFCS for recovery?

I'm actually not too familiar with autoFCS; what features are you looking for?

 

[Pipcard]

AutoFCS is an runway landing autopilot (from low Earth orbit!) designed for the Shuttle Fleet add-on.

And you'll have to do some things before getting it to work in Orbiter 2010.

 

[orbitingpluto]

I like the plan as well, though if possible I'd like to see a development feature that gives people a line in the scenario file to add mass to the Skyhammer, 'ballasting' it to test ascents, landings or etc. as if Skyhammer was carrying payloads.

Just gotta say though, that screenshot

 

[ADSWNJ]

Don't worry about the reentry assist as I'll have Glideslope working and profiled for this pretty quickly. Just give it XR-like attitude control (ie AoA, bank control on coarse and fine).

Ditto RV Orientation for on orbit ops.

Loving the look of this vessel!

 

[kocmolyf]

I don't really know how to take a screenshot for this, so I'll just infodump:

1. Fixed all the inverted/degenerate normals in the mesh.
2. Set up a proper project structure.
3. Set all dry and wet masses. Inertia tensor and cg are still messed up.
4. Main engines work! Starting fully fueled in low Earth orbit, Skyhammer can eject at ~15 km/s without dropping the external tanks.
5. Pitch/yaw control via thrust vector control works (no RCS thrusters at all yet)! I'm sure someone else has done this before, but control via engine gimbal seems to be a rare thing in addons.

Obviously lots of ground left to cover still, but it's a good start. Next up is probably deciding how I want to blend commanded roll into the steering controller, since pitch/yaw angles and roll angles directly interfere with each other.