Project Here goes nothing: The Delta-StarLiner G42

[Urwumpe]

I don't know how well such a thing would work at hypersonic speeds

simple: Almost no effect. By changing the air pressure artificially, you can change the supersonic airflow a tiny bit, but not dramatically. The wing shape offers better chances.

For feeding engines at high AOA, you would need a "flap" or spoiler in front of the engines that extends into the airflow and deflects it towards the engines. Downside: It makes the vehicle harder to be controlled, more complex and more sensitive to inlet stalls.The vibrations should also increase a lot that way, increasing wear on the engine inlets.

 

[Moach]

well... i don't think the concept of a drag-reducing surface such as this would go as far as "sucking" air through microscopic pores... that does seem like more a problem than a solution...

the G42's external coating should resemble more that of a golf ball, with small, yet manageably-sized dimples that reduce surface friction... still, unlike a golf ball, those dimples aren´t simply round, but shaped in formats optimized for high-speed flight...

but it's mostly about the shape of the wings... not having rudder surfaces sticking out also helps



although the G42 isn't supposed to sustain prolonged high-AoA flight, the engines are fed by a combination of the inlets above and below the wings, depending on flight configuration... but air for actual combustion is provided mainly from the inlets below....



and it's not the engines that can get the max bang-for-buck ratio... it's the whole construction of the vessel, by using lift, rather than brute engine power, you save a lot of fuel, being able to achieve orbit without having to consistently produce more than 1g's worth of thrust


also, for takeoff, when the ship is heaviest, a cheaper variant of an SRB is employed... those are called DARTS (Disposable Auxiliary Rocket Thrusters), and are basically small solid boosters, with about 30 secs worth of juice that avoid having the ship at a high induced-drag moment due to excessive AoA upon takeoff
when spent, the DARTS are ejected over the atlantic without any remorse... since they are cheaper to build than to salvage...

 

[Zachstar]

Shape does matter a great deal yes but going into orbit slowly means more fuel used. Because you spend more time in altitudes where drag is present instead of spending it at altitude where little is present. Something that "changes" that is pure sci fi in my opinion. A great idea in terms of reducing airframe stress but not a fuel saver. Where engine isp matters much more.

The SRB sounds like instant nogo for serious everyday travel. Take one serious look at what it takes to prepare and maintain solid propellant,casings, and maintenance and you will see that they are a nightmare. It also means great stress on the airframe increasing costs in my opinion.

 

[tblaxland]

dunno if you´ve seen it, but a special suit has been developed that allow athletes to swim faster by reducing surface friction... the suit has such a fiber pattern that imitates the skin of a shark, reducing water drag.

Warning: These my own educated guesses. Anyone please tell me where I'm wrong, if appropriate.

I think the main benefit of those suits (despite the manufacturers claims, because it is against the rules) comes from increasing buoyancy because the skin is unable to absorb as much moisture as it normally would when it is uncovered. Greater buoyancy = less form drag = more speed. This is especially notable for the case of the pure polyurethane Arena X-Glide. No such gain would exist for a vehicle fully surrounded by air.

The triangle "shark skin" parts found on the Speedo LZR are meant to be like the vortex generators on an aircraft wing, reducing the drag due by delaying flow separation. I have a feeling that vortex generators would not be very effective at hypersonic velocities though.

 

[Moach]

(...) I have a feeling that vortex generators would not be very effective at hypersonic velocities though.

i think probably not...

when the mach readout gets into the 2-digits realm, air is not so much air as it is a wall of concrete...

the rugged surface proves itself valuable only at subsonic speeds... which is a good thing, since that's particularly when the craft is heaviest (or gliding with no fuel, after reentry) - so it has it's value, but not during hypersonic ascent...

what makes it drag less, is basically the shape of the wings and body... notice it has no rudders, or any type of protruding surface... the ship has a blended-wing-body design which allows for more fuel capacity whilst maintaining a sleek profile


despite of that, fuel efficiency should benefit from atmospheric flight... flying a "depressed trajectory" allows external 02 to be used, and ram air to be exploited... according to the Falcon project video, it's scramjets could sustain efficiency up to mach 20... we would't wanna miss out on that now, would we?


and now that i think about it... any kind of solid booster, disposable or not, is indeed a nuisance... so this is not a part of any SATO (Standard Atmospheric Transition to Orbit) procedures, and is reserved for special missions with overweight cargo and stuff like that...

i've recently modeled the landing gears, which i have programmed as far as animating goes (no drag increase or touchpoints toggle yet) - but it's going rather well...


i still have several doubts as to how to implement the RAMCASTER and turborocket engines...

obviously, i figure i could use 4 different logical thrusters, for the following "stages":
1 >> airbreathing turborocket (mach 0 to 1.5)
2 >> RAMCASTER "lo" ramjet (mach 1.5 to 5.0)
3 >> RAMCASTER "hi" scramjet (mach 5.0 to 18.0)
4 >> onboard-O2 turborocket (... and beyond)


the i figure i could fuel them with two different "tanks" one for propellant (same for all stages) and another, smaller for O2 (only used by the latter)....

but, Orbiter doesn't quite makes the difference between propellant and oxidizer... so how should i proceed on this? do i make a small tank and empty it out "manually" when in onboard-O2 mode?


how should i set the ISP's an thrust ratings of the engines so that this goes on realistically?

 

[MeDiCS]

I'd like to ask the most important question: when ?

 

[Moach]

hmm... as for that, i guess the only reasonable answer is: "when it works"...

model still need a bunch of work (and textures)... and i still need to figure out how on earth those engines are gonna be simulated... still needs a bunch of animations too...

but once i get at least some of that up to speed, i guess i'll release a "this is what i have so far" package, even if it's not all daisies at that point :hmm: (sources included)


but first... what are realistic ISP and thrust settings for something like that?... and also... how much would it weigh? considering the advanced materials used in it's contruction?

 

[Zachstar]

A quick question as I am confused.

You seem to mention hydrogen earlier. Indeed it would have the benefit of being easier to combust perfectly with 02. However with its low density even in a liquid state. How are you going to explain the large amount of Hydrogen used to push it out of the atmosphere where its higher ISP matters?

 

[T.Neo]

Perhaps slush hydrogen instead?

Or perhaps Metastable Metallic Hydrogen... :hmm:

 

[Zachstar]

Arent those methods meant for storing hydrogen gas for use in cars in situations (99 percent of the time) where cooling and having a bunch of extremely cold LH2 on hand is a bad idea?

I saw some "what if" images of Hydrogen airliners. They had very large tanks over the craft to store the hydrogen needed for a transatlantic flight. Something not very feasible for anything going Mach 1+

 

[Moach]

yeah... that ain't hydrogen driving those engines... too inconvenient... who needs all that icing anyways?

not to mention LH2 is so thin, it leaks out of the tiniest gaps... quite a mess...


no... i was thinking the fuel should be something else... preferably with higher energy-per-kg ratings...


what would you consider a viable option?

 

[Zachstar]

It depends on how this engine is. JP fuel is today's top energy choice but I am curious if perhaps you could use a fuel derived from algae (For economy and purity) that could be a bit more full of hydrocarbon content to react with. Obviously you would not burn pure algae oil but you get my drift. Something a tad more thick and hydrocarbon than JP fuel. JP fuel would likely work fine but I am curious (mainly for my own design I am toying around with) If something else would work better.

 

[River Crab]

I think the DG-EX supposedly has 3-mode engines, though I'm not sure how they work...I can't get the newest beta working so I don't know how it's going, but the DG-EX seems similar to this craft. I don't know how it would work, I'm terrible at C++. I also second the idea of a top docking port.

While it's still early in development, I'd like to give my 2円.

I think you are going here, but please try to refrain from mouse-only commands. That's my big problem with DGIV.

How about a cockpit view (ctrl+up) that would look up the top windows, and one that looks into the bay. I don't think that's too hard, right?

The body of this ship is already distinct, so IMO the nose looks out of place. Specifically, it seems too short for hypersonic flight. Perhaps add some tapering? It's only semi-realistic, so make it look fast! I do understand that the RCS positions are hard to get right, so maybe just change the part forward of that point, or something. Use an XR2- style nosecone?

I know how to solve the engine exhaust clipping problem. The trick to position it is not inside the engines chamber, but just outside.
Somebody put this up long ago on the XR2 dev thread but there's no way I can find it anymore.

Also, what of sounds? I envision it sounding much different than the tiny DG, especially with the different engines.
Engines: A screaming banshee until internal oxidizer kicks in, then a loud rumble. You could make the sound for the engines changing modes work similar to the DGIV's turbopump.
RCS: I imagine the RCS sounds deeper and more powerful. It's big!
Doors: I dunno. Maybe when the airlock opens, it says, "Mind the gap.":lol:
One thing that really characterizes a ship is the cockpit sounds. Like aircon, hydraulics, and especially voice callouts.

"Beep beep...Warning!...Beep beep...Warning!"
That's DGIV, obviously:lol:.

"BOOP BOOP 'Warning. Hull temperature.' BOOP BOOP"
That's XR2. I love that voice.:thumbup:

I'll volunteer some sounds I can find, if you will. Just tell me what you need. I'm a dowser, I'll find it!

Textures make the mesh, so seriously, do not skimp on textures. Most modern computers can handle fairly large textures anyway(That could be a lie). Take a hint from Mustard's addons, or the XR2. Everything has texture, and not just panel lines. I mean burn marks, metallic lustre, everything. Although, Coolhand is a pro, so don't kill yourself if you can't get it perfect. Save the texturing for near the end, though. Definitely plan to make a paint kit available, with layers and stuffs. You can save yourself some work when skinning it. I'm sure the forum will support a craft with such promise.

Also, what is this ship really meant for? Cargo, I guess? The name "Starliner" implies passengers, but I dunno. Your main missions would then be space station resupply/assembly, building large vessel stacks, and refueling orbiting vessels. As for companion vessels/addons, I'd select the Ess by Mustard, Greg Burch's Space Station Building blocks, and perhaps the up-and coming XR0 from dbeachy and Coolhand. Also there's no way you can forget UCGO boxes. I say this because you'll have to size the bay accordingly.

Speaking of UCGO, it would be awesome if the starliner were as compatible with UCGO as the DGIV- can use resources, etc- but I understand this may also be a burden to code added onto the project. Save those things for last (but leave accomodations now).

What of nationality? The XR series is British-American because of its developers. Brazil doesn't have a space agency, though...
Maybe a Brazilian private enterprise?
Or French/Brazilian, since they launch from just north of Brazil.

Sorry if that post was too long. I tend to do that.
Anyway, keep up the good work, and don't forget to Hail !

 

[Tommy]

Warning: These my own educated guesses. Anyone please tell me where I'm wrong, if appropriate.

I think the main benefit of those suits (despite the manufacturers claims, because it is against the rules) comes from increasing buoyancy because the skin is unable to absorb as much moisture as it normally would when it is uncovered. Greater buoyancy = less form drag = more speed. This is especially notable for the case of the pure polyurethane Arena X-Glide. No such gain would exist for a vehicle fully surrounded by air.

The triangle "shark skin" parts found on the Speedo LZR are meant to be like the vortex generators on an aircraft wing, reducing the drag due by delaying flow separation. I have a feeling that vortex generators would not be very effective at hypersonic velocities though.

The reason they looked at shark skin wasn't just low drag, what caught the scientists attention was the fact that most sharks (the ones with this pattern) don't have algea, barnacles, etc, clinging to them, while virtually every other sea creature does. Somehow this surface pattern makes it almost impossible for anything to stick to it, even microscopic particles. They are using it to make wall panels for operating rooms, since even germs can't stick to it and it's much easier to sanitize.

As far as I know, the only research involving this with aircraft is about using it to prevent icing - the drag reduction at subsonic speeds would be insignificant. I have no idea what it would do at super or hyper sonic speeds.

As for it's low drag, I understand that it doesn't disrupt the boundry layer so much as it allows the boundry layer to move over the surface faster (or become thinner?), meaning less difference in speed between the boundry layer and the freestream. Or something like that.

 

[Zachstar]

I ought to have detailed what "Algae Oil" is.

Basically its oil very similar to oil from the earth. But without all the crap. Carbon content is extremely high and its made by algae either from bioreactors that grab Co2 from the air or the far more efficient method of using algae that eat organic matter such as sawdust or crap grass.

Something similar to this. http://www.solazyme.com/content/technology

Its green and ensures your flights are not affected by oil speculation or peak oil. And it is very high quality JP fuel or whatever you distill from it so the engines run better.

 

[MeDiCS]

What of nationality? The XR series is British-American because of its developers. Brazil doesn't have a space agency, though...
Maybe a Brazilian private enterprise?
Or French/Brazilian, since they launch from just north of Brazil.

We do have an space agency: Agência Espacial Brasileira (the failed VLS-series of launch vehicles is theirs).

 

[Moach]

how did i not notice you were brazillian too before?...

nice to see some countrymen around here :thumbup:



ok...
as for the blunt nose cone... it is a copy of the stock DG's nose... and by copy i mean ctrl+c, ctrl+v in 3ds max... lol...
i though of changing it to something more concorde-ish... with maybe a droop-nose and a supersonic visor, those are COOL...
but that would possibly mean losing the nose dock, which would make for harder, shuttle-style dockings from the cargo bay (anyone up for a challenge?)

like the XR5, an alternate RCS behaviour could be used to fly her into the perpendicular dock... it's just a matter of switching the thrusters from Z to Y and vice-versa

still in time to change that... whadda you think, ppl?

i also thought there should be VC positions for operating the cargo bay... pretty much like the XR5 (where's doug?) then you could manipulate payload items and such...


the main purpose of this ship is to function as a general-purpose surface-to-orbit vessel for crews and small/medium cargo, depending on launch configuration...
it is meant to be ground-support-independant enough to be flown from conventional airports with not too tall adaptations... at least for low-profile missions, such as ISS shuttle and stuff like that...

advanced computer systems onboard can help minimize the amount of real-time ground telemetry as well, allowing for multiple simultaneous missions with "houston" acting more like as an ATC center than that whole "guys about to turn blue" operation we have todays...



as for sounds, i've already changed the a/c sounds to something "heavier", which gave it a nice feel... the engines do need a "screaming" sound when using external o2, and a higher-piched whistle during ramcaster flight

there will be multiple audio callbacks from the cockpit, announcing anything that may matter... pretty much like in doug's XR ships...



as for the surface patterns, back when i took sailplane lessons, i learned that a dust-free wing has a noticeable performance increase over a dirty one... (or perhaps they just said that so i'd clean it up for them?)

so this surface pattern should also help in maintenance....

there's no data on how this would perform in hypersonic flight... so this is where things could go sci-fi if we start assuming things... for that, let's just say it gives a better glide-down on landing and helps in takeoff as well...

i have my doubts anything this delicate would affect the bruteness of mach10+ flight...


now i feel a bit stronger towards changing the nose... it would look incredibly cool...
i also think the wings could have a sharper profile... perhaps more swept, less span?



as for algae for fuel... that stuff is REALLY cool, man! quite a find!
Brazil does have a nice lead on organic fuel technologies, we've been driving on alcohol since i can remember and have some nice projects involving bio-diesel and stuff like that going on...

also, we don't have a solid space program, but our aircraft industry is rather strong

so i think the G42 could be something created as a mainly private, government-aided, collaboration between Europpean, Brazillian and Whatnot companies...

i dunno, i'm just the guy who makes up the ships, not into that much corporate politics...

 

[Zachstar]

Politics are very important if you want this to be anywhere near future realistic. You cant just pull a Bush Jr and throw a lofty goal without delivering the funds and tech to support it. It ends up being canceled after the opposition gains power.

And yes I hear a great deal about Brazil and biofuels. Tho not too too much about algae oil. No big deal tho. By then most of the JP fuel produced would likely be through algae or bacteria anyway.

But say it just used normal JP fuel. You charge such and such per ticket. But if fuel skyrockets due to an attack on a pipeline or demand grows or even speculation... You will have to charge more per ticket more per pallet of cargo etc... This means less customers and bigger chance of reduced flights or even cancellation. It happened to the Concorde it can happen to this.

Algae oil is way more versatile however. Your main production would be from algae that feast on organic stuff such as crap that remains from harvesting sugar or corn or even easy to grow crap and even pay people to gather crap that takes over areas (Kudzu in the US can be handled similarly) Secondary production would be algae that is grown in bioreators or ponds that suck in CO2 to meet carbon credit or whatever targets.

Much more important tho is that Algae oil is clean. Superior JP fuel is important if you want those engines to be economical.

 

[MeDiCS]

how did i not notice you were brazillian too before?...

nice to see some countrymen around here :thumbup:

 

[Moach]

yeah, bio-fuel is looking pretty sweet for powering my engines, and without all that bulk needed for LH2... which again, makes for less drag and even more reduced fuel chugging...

i tried today but couldn't make a concorde-like nose look as cool as i had hoped... kinda looks like a duck, and throws off the visual balance too much...

i'll try again tomorrow, or when i have some time to do it more patiently... but i'm starting to think it's not gonna be easy to get it looking right...
so is this something you'd wanna see or is it just "meh"?,
'cause its looking rather inconvenient to have to scrap it later...


would be very cool... flying with the nose down in orbit, putting the visor up for scram flight and reentry... would be a lot more realistic, with a hypersonic-worthy look to it

but, on the other hand, it's a handful re-design of the nose section, and will make it impossible to nose-dock like the DG does, leaving us to do it shuttle-style

please pitch in, i don't wanna have to go back on this one...



now... as for coding... i'm having some trouble changing the font used for outputting text onto the dynamic textures... i can write and draw some stuff... but i can't compile if i try to instantiate GDI brushes and fonts...
any advice on this? should i ditch GDI and try using DirectDraw instead? is that even possible?

---------- Post added at 07:40 PM ---------- Previous post was at 07:22 PM ----------

well... a brief research learned me that the only reason for concorde's droop-nose, is to improve the pilots' visiblity during high AoA... not as much about aerodynamics as i hoped...

so something like that wouldn't make much sense in a ship like the G42... being it already has great cockpit visilbility....

yet, i still think it's windshield does look a tad unpropected... i believe some sort of visor could extend from the top of the nose, then we could not only secure the windshield, but also create a more streamlined profile with a wee bit longer, pointier nose...

this seems like something a bit more possible... maybe it could work...