Project Here goes nothing: The Delta-StarLiner G42

[Moach]

i'm thinking i should make a video about flying the G42, and how it seems to perform best....

i see a lot of you are flying it too high at first, which makes for a troublesome orbital insertion

i usually fly 'er like this:

takeoof - hit full throttle on the main-ext, rotate at about mach .3 (100-something m/s)

pitch up slowly, as to avoid a tailstrike, but do not allow the nose back down, she'll steer madly if you do

once you're airborne, retract the gears - then (very important) throttle back to about 60% (this will be needed upon further development, which will simulate engine overheat) - and this should keep you in control, since it won't try to pitch up so hard...

turn east, so you can use the earth's rotation to your advantage (we don't wanna miss out on ~400m/s of free deltaV, right?) keep below mach 1 - pitch up to control your speed... as you level off onto heading, raise the nose visor...

let it accelerate with pitch between 20-30 degrees, you should become supersonic at about 8k alt
at that point, your engines are at peak efficiency, feel free to throttle up again, you wanna reach mach 2.3 as you pass 20k alt.

when you get there, your engines will begin to grow weak, you'll be wasting precious fuel if you continue like this - so switch to RAMX | LO

now, nose down slowly to keep you vector below 10 degrees - you don't wanna lose the "good part" of the atmosphere - keep going to reach mach 7 at 35k~40k alt

now switch to RAMX | HI.... hold on to your attitude, you can even pitch down some more, so you climb just enough to keep the nose cold as you accelerate....

you should come about mach 18 at ~60k alt....

your engines will be growing mighty dim by then... but you may have to hold on just a while longer, as you wanna burn any extra fuel that may exceed you oxidizer supply (which should be minimal, if you've done everything right)

oxidizer burns about 1.5 times the ratio of propellant flow - so you should be "balanced" when you propellant is at roughly 30~35k....

blast the switch to MAIN | INT and power through onto orbital speed with as little vertical speed as you possibly can... you should get your ApA at around 400k still in atmosphere... (remember that because of this, you should shoot a little higher than your intended target, to compensate for drag)

now, sit back and enjoy the ride half-way around the earth - you can lower the visor when density goes zero.... once you hit your ApA, burn prograde again to circularize....

now, it's safe to open the cargo bay... congrat's you're in orbit


of course, a lot of this procedure may not apply to the current version, as a lot of flight tuning went down this week - worry not, the new WIP release is already cooking :thumbup: :cook:


i wouldn't advise attempting a reentry without FBW stabilisation.... but if you wanna have a go at it, go nuts!... i just don't guarantee your safety in doing so :lol:

i'll try to have the new WIP up before weekend

 

[Usquanigo]

when you propellant is at roughly 30~35k....

OOC - how much fuel does it carry? (and supplemental to that, how much physical space would that amount of fuel actually take up - then is that space actually present?)


BTW - earlier I was talking about high and low wing, and you made a comment about a large wing. You probably knew what I meant, but I just wanted to mention it here JIC - the G42 uses a low wing (low mount), like the shuttle or F-4 Phantom. A high wing (high mount), would be more like the F-15, F-14, Flanker, etc. They are more efficient because lift comes form the top of the wing and in a modern design it utilizes the body as well (basically a BWB of sorts). That would provide more lift, or the same lift with less weight (through smaller wings). (also, those bumps would detract from total lift as well)

I'm not criticizing or complaining - just having a geeky discussion.


Great news on the new WIP!

 

[GuiConteDGIV2X]

please stop to sue me i m not from sierra leone i am kidding please have mercy

---------- Post added at 04:02 PM ---------- Previous post was at 03:52 PM ----------

like hit earth at 14e40 pc per second? that will really hurt!! :lol:


ps:faster than a asteroid i think it is like 100000000000000000000000000000000000000000000000000x more faster =O

 

[Izack]

like hit earth at 14e40 pc per second? that will really hurt!! :lol:

You'll reach the end of the Universe before the Earth finishes sublimating from the impact...assuming that someone threw relativity out the door. :lol:

 

[Moach]

I'm not criticizing or complaining - just having a geeky discussion.

isn't that the whole point why we're here? :lol:

OOC - how much fuel does it carry? (and supplemental to that, how much physical space would that amount of fuel actually take up - then is that space actually present?)

the G42 carries 115 tons of propellant (liquid) and additional 45 tons of oxidizer.... i guesstimated those values from specs of similar aircraft... the concorde carries about 95 tons...

and the G42 is actually bigger than the concorde, AND, it's passenger and payload mass and volumes are pretty small in comparison

based on that, i drew the conclusion that such amounts of fuel are valid in a realistic manner - it is a lot of fuel - indeed... but empty, the G42 weighs at 38 tonnes... which is a little over half a concorde.... gotta love those composite materials right?

i too found it strange how much fuel really goes inside the tanks on aircraft... but it's real... that's one of the greatest advantages of going hydrogen-free... you can have a MUCH smaller ship:tiphat:


as for wing positioning - high wings yield better stability, since the center of lift is higher than the center of mass, which allows the plane to "hang" using it's own weight to pull it back into coherence... low wings, however, make for a seamless surface on the bottom which allows the whole underside to provide lift

but since handling is a non-concern, provided we have FBW, we can choose performance over stability - (airbus does this, and that's why their planes look strange)
and having a high-mounted wing wouldn't sit too well during reentry, right? - it'd be a lot harder to properly heat-shield an irregular surface

 

[Usquanigo]

The heat sheilding aspect is a point. But with some aerogels, it should be possible. hehe Actually, it certainly would be easier and cheaper to have a flat surface.

As for lift though, the underside only contributes in a Newtonian fashion, which is a very small portion of overall lift. Even at high speeds. This is why the F-4 was such a bus compared to the F-15 (which carried the same amount of ordnance, but was MUCH more agile). Yes a lot of other factors are involved too, but it's the same companies next gen design. All they did was evolve the Phantom to meet the USAF's new requirements. (and the Phantom was itself an evolution of the Demon)

This is also why all stores are slung under the wing. Yes, pulling Gs means it's better for a missile to be underneath, but dive bombers never pulled Gs during a bomb run (only after), and engines don't shoot off, and tanks aren't used as weapons. The real reason this stuff is slung underneath is because even at high speeds, the upper surface (Coanda) is what actually provides the vast majority of lift.

This is also why Antony Fokker was able to take the Dr.1, scrap all but the upper-most wing, and have the D.VIII be practically as good of a performer. (because the lower wings' upper surfaces weren't getting clean air, so their contributions were diminished)

Hey..... there's a thought - a high and low wing, simultaneously. Even more of a BWB design. Like how the fuse of the Fulcrum, or Flanker or Eagle or Tomcat all fade/blend into the upper surface which itself becomes part of the wing, you could do the same on the bottom as well. That would solve both problems at once. :hmm:

....if only I could 3D model worth a damn, or even more importantly, figure out how to get textures applied to a model. I was never able to do that, even on a rocket/missile body. That caused me to give up on modeling out of sheer frustration.


Anyway, I'm not suggesting doing something "better" than this - just rambling (as I have a tendency to do), as a result of the aero conversation.

 

[GuiConteDGIV2X]

hi guys im just playing velcro rockets

Now do you know what s the release date of the next wip?

HAIL PROBE

 

[Moach]

if all goes well, in a few minutes :thumbup:

---------- Post added 08-13-10 at 12:31 AM ---------- Previous post was 08-12-10 at 09:44 PM ----------

and there it is! uploading now :thumbup:

recent changes include:

OMS thrusters
Fly-By-Wire stabilization
thoroughly revised flight model
Airbrakes
redesigned cockpit frame and MFD buttons layout
dual-truck main gear bogies (still very crude)
freely-operating bay doors
onbard oxidizer simulation
infinite amounts of awesome

get it while it's hot! - (WIP 3)



:hail:



cheerz

 

[Izack]

Awesome! I was getting worried how I'd spend my time tonight.

And what better way is there to spend a lonely night, than with a shiny new spaceplane release? :lol:

Also, first download GET. :hotcool:

 

[River Crab]

OMG! I just managed to steal- er, get wi-fi during another trip, and this happens! Perfect timing! :lol:

BTW, Now that I have rudimentary knowledge of Illustrator, I might be able to really do that logo- for real! I 'd REALLY like to get a jump on texturing, even though I know I'll have to do it over again. I'm fine with that.

Also...
Second download GET! :banana:

 

[Eccentrus]

which means that I'm the third downloader :lol:

 

[Usquanigo]

And what better way is there to spend a lonely night, than with a shiny new spaceplane release? :lol:

:hmm:

I have a feeling I could think of a way..... hehe


Moach, due to the size, I take it this is meant to layer on top of the WIP2 release? (rather than being a standalone install)

 

[Moach]

nah, this one is smaller because it doesn't have all the sources included... they were too large and i needed to go to bed, so i took ´em out for a faster upload

i'll add the sources on the next one :thumbup:

you can simply have the files overwritten... it should work just as well... but it's all there, it's perfectly standalone :hmm:

 

[River Crab]

Hmm, I've found an interesting bug, or something.
Every time I shift the CoG, the center of the vessel (the origin of the vessel's axes) moves +y from the mesh- so if you shift it too much, it will be in front of the vessel. So the reentry plasma appears where the center is, rather than on the mesh where it should be, and the camera focus moves forward as well. It doesn't matter which way you shift the CoG, the center always moves forwards. This is visible if you turn on visualisation of axes. However, the cockpit view is correct; if you shift too far, you can see the axes in front of you from the cockpit.

:shrug: Weird.

Otherwise, looks good! Suggestion I'd make to the cockpit is to remove/narrow the edges on the sides so they don't stick into the front dash, and make the MFDs the same with buttons on bottom. And perhaps add an overhead panel, and power buttons for the SYSMFDs?
Can't wait to see the LCD buttons working. I agree with Usquanigo, I kinda liked the old layout, but the new one does seem a more solid and able to withstand pulling a few Gs. You can totally make it work.

Also, I just realised how cool the visor mechanism is! :thumbup:

Keep it up!

 

[Moach]

yeah, the CoG shifting rig is severely bugged out....

i'd advise you try to fly without it, as it seems to work only to shift forward, and not to bring it back around :shrug: - which is particularly bizarre, since i've double checked that code a bunch of times and didn't see anything that would appear to be the cause of this :blink:


in recent flight tests tho, i noticed it was perfectly possible to trim it out in a way that the CG-shifting thing is hardly needed... so i'm thinking there's no need to bother the pilot with that, as it can be safely, ermm... "relayed over to the flight computer" :shifty:


and i'm still not done with that cockpit.... i just might change those panels around some more.... that part that intersects with the front dash isn't quite the way i intended it yet... it'll get there... just needs more patience

but i feel more confident with the new panel construction.... the angled MFDs from before appeared more and more to me as if they were to break out at any moment :lol: we wouldn't want THAT... right?


moreover, there WILL be an overhead panel - did you notice the base for it is already there? - and in that panel, there will be an avionics switchboard, where you'll find the controls that power the MFDs and other stuff :hmm:

if i can have my way, this thing is gonna have more switches than that PMDG 747 for FSX.... i can think up myriads of systems that would be sooo cool to have simulated :banana:



EDIT: hey cool! this post was my 500th

 

[Usquanigo]

Congrats on the 500th. :thumbup:

Switches are cool, but I'd recommend not going too overboard. Remember, this is 2010, and that ship is probably, what, 2015 or something? Most systems would be automated and reliable, generally just 1 master on/off, and perhaps tweakable through some sort of I-Drive interface.

Goes back to the car analogy I used in the DG-IV vs XR-1 thread - the only reason to have timing manually controlled from a lever, plus a mag switch, plus straight cut gears with a need for double clutching and a hand crank is because at one point it was necessary. Then when starters came along, they were seen as unrelaible. Ditto fuel injection. Ditto automatic transmissions. Ditto computer controlled EFI and timing. Ditto aluminum engine blocks... you see where this is going. Now my 2002 Trans Am has an all aluminum LS1 with super short pistons, displacing 350ci in a small block(!), computer controlled injector pulse timing and duration, and computer triggered ignition coil packs. The only thing it's missing is the VVT and displacement on demand from later LS engines. And I could drone on about traction control and ABS too. None of those things are accessible to me. I just turn the key and drive.

A similar parallel happens in military planes too - F-4's needed RIOs/WSOs, the F-15 eliminated that need, yet had even more advanced radar, and so on.

 

[River Crab]

woot 500! :banana:

This cockpit is going to be very realistic anyway, so as long as it's not like, the Dragonfly, I don't mind some "extra features". Like the switches on the DGIV that turn everything off.
Fighter jets are a better analogy here but I think there's no need to say much more about cockpit "realism".

2015? I dated it 2060...
Considering that things go well, and history wasn't changed drastically before 2010...

Also, that little thing right in the middle...that is some kind of radio, correct? How will that work?

And, maybe you should consider releasing it first without an ODS, and making it an add-on vessel, or another version with an ODS (or an airlock)?
I'm curious, is it possible to transfer UMmus between vessels that aren't docked? I think so, otherwise, how do those UCGO displacement booths work? :idk:

 

[Usquanigo]

"ODS"?

My thinking is grounded in today. Engineering-wise. Meaning, what is possible that we (or at least I) know of? That's where all my questions in this thread come from. I don't like to use handwavium and just assume "well, it should be possible by then" - unless we know how it can be done today and just haven't done it yet.

So... under that, if we assume that it is physically possible to do, right now if we had a blank check (book).... then it could concievably be built in 5 years. I first thought 2020, but that's a "special" date for me which should include other craft entirely, so I rolled it back to a nice round number. :lol:

 

[River Crab]

ODS: Orbiter Docking System.

Yeah, I suppose "if we really wanted to", we could build such a thing much sooner, but I don't like to assume perfect worlds. Most of my dating was due to red tape and the fact that I couldn't find a Kindle screenshot that had a "5" in the date.

 

[Usquanigo]

For some reason, I couldn't get any thrust out of the RAMX in either HI or LO. So I tried to cycle back around to MAIN | EXT and ended up on MAIN | INT and then managed to get an orbit of something like 9.945M x 68K. :lol: :embarrassed:

The good news is that it really let me look at/play iwth the new atmo model in O-2010 - it was way cool seeing mach speed increase when I was like 1Mm out, then watch the IAS and DynP increase when I was above 100Km.

After about 3 orbits, I managed to surfe the atmo to bring the ApA down and raise the PeA a bit, to about 8Mm x 80Km or there-abouts.

Makes me suspect there's just a bit too much fuel, or maybe thrust, on board. (for it to get _that_ high. It would take several orbits, but I know I could get it circularized with RCS only, bringing the ApA down even further)

Moach, what is that little display front and center on the dash, above the middle MFD?

Any chance you could set up a 'downshift' option on the engine? (going backward through the cycle)

The FBW is awesome, it flys very nice. It's really coming along. I'm still partial to the older pit, and didn't see it as G sensitive at all, but the new one is nice too. It's especially cool at night. :thumbup: I would simply illuminate the buttons, rather than adding pit lights... when you get that far along I mean. Or maybe both with the light as an option, because with the buttons themselves illuminated (like in a car - door locks, windows, HVAC, etc) you won't need ambient lighting and it will look far cooler.

When I had it trimmed out, I noticed the split flap brakes were out. Should that be? Seems to just create drag for no purpose.

The CoG said -1 or something, and I don't even know what keys to use to change it, so I assume I didn't do that.

A throttle position indicator would be good too. I assume you are going to animate the hands at some point, and that will help, but right now I had to go to wonder women view to see where my throttle setting was.

For some reason, the HUD said ENGINE | OFF and I was apparently out of fuel, but I was continuing to accelerate and externals showed exhaust still coming out. Once I saw my ApA hit 400+, I tried shutting it down manually and it didn't respond. It just kept going. Like it was a speed demon with a mind of it's own. :lol: