Project G42-200 StarLiner

[Moach]

well... about that...

but i do see the science in it, i just doubted it for a moment

and i meant to ask before: can we have some expected [rough] specs of the ship?ones like
weight
fuel mass
Dv after scram stage

and for my own use;
landing gear wheelbase
craft length and wingspan (for all configurations)
and a rough turning radius for the beast*,

*im amidst making a spaceport in central Africa designed to accomodate XR5s, i would be devastated if this craft wasnt compatible with my taxiway system.

also, i might make a tug for it in UGCO if i can work out a nice way to do it, and if i can have a model to build my tug around (i get EXACT measurements from your model, so mine fits perfectly)

and finally, when do we get to see a model of this? if you are doing textures first, i suppose it would be a while, but i cant wait to see it (do the meshes first, then all the coding, so we get to see it nice and early)

thanks man!

hmm, let's see... as for the model, i´vé already started work on it... got the nose section and foward wing-body blend bits somewhat modelled... (i did spend a bunch of time just setting the 3ds max UI so that working with it is, you know... tolerable)

as for those specs, i'1m really not sure ATM... i can tell you that the G42-200 is just over the size of a 747 give or take... so that's about 85 meters long, as you can see here in this ship-vs-man size diagram:

not sure either about fuel capacity.... i don't wanna throw loose figures out there, so i'll do some measurements for volume, etc, when the model is a little more coherent....

 

[Grover]

and what about wingspan and wheelbase? if they're XR5 ish or narrower, i dont have to do any major changes to the base, except a change to the hangars, since i guess that 80m is a bit long for my hangars at the moment

i dont need accurate values yet, but please tell me it can turn over a 90m radius, i have 60m taxiways running around my base with turning radii of 90m

also i tried the 100 series WIP, and it wasnt bad at all, but a little bit of a pain to get it into orbit i found, i think there should be a bit of a system in place to hint at you when you should change engine modes, either a G-meter, engine thrust readouts, and as a major thing, consider a readout of projected next stage thrust, so you can see if its feesable to "gear it up"

ill bring this back up when you start on the new VC, but for now, can i just say: make sure you put some engine noises in there, it was creepy doing .4 mach on a runway in near silence

and finally, if i get the hang of it in a sort of beta test environment, i might even write you a PDF documentation, depending on how much time i have in the future and whether or not i manage to get it to orbit

later man!

 

[Moach]

and what about wingspan and wheelbase? if they're XR5 ish or narrower, i dont have to do any major changes to the base, except a change to the hangars, since i guess that 80m is a bit long for my hangars at the moment

i dont need accurate values yet, but please tell me it can turn over a 90m radius, i have 60m taxiways running around my base with turning radii of 90m

also i tried the 100 series WIP, and it wasnt bad at all, but a little bit of a pain to get it into orbit i found, i think there should be a bit of a system in place to hint at you when you should change engine modes, either a G-meter, engine thrust readouts, and as a major thing, consider a readout of projected next stage thrust, so you can see if its feesable to "gear it up"

ill bring this back up when you start on the new VC, but for now, can i just say: make sure you put some engine noises in there, it was creepy doing .4 mach on a runway in near silence

and finally, if i get the hang of it in a sort of beta test environment, i might even write you a PDF documentation, depending on how much time i have in the future and whether or not i manage to get it to orbit

later man!

alright! nice to see some interest in helping out :thumbup: - alway a good thing! thanks!

ok, as for taxiing, the G42 doesn't really "taxi" more or less... it gets "towed"... being a highly fuel-sensitive spacecraft, when on ground, it's usually a better idea to have a tug drive 'er all the way to the runway... engines should fire up just in time for takeoff...

i have in fact, considered actually modelling the tug itself, and whatever that means in terms of getting it to actually pull the G42....

anyways, this tug would be a specialized machine... it should latch to the front gear and simply drive around like a truck with a trailer... and what a traile3r that would be - while the tug taxies the G42, the already-boarded crew runs the pre-start checklist and gets her ready for engines-up - the tug should provide external AC elec from it's diesel generator, and is accessible from the G42 cabin even while moving, via the hatch and ladder on the front gear strut...

hang on... i think i can draw it up quickly

 

[Grover]

well, the problem is far more practical: if you use a UGCO car, as is most sensible, the aircraft wil then become essentially, neglected in terms of the tugs movement, and even worse, the aircraft will pivot around the tug, not its rear carriage, which is incredibly unrealistic (imagine the rear carriage of a 747 sliding over the ground, 70* slip from the direction they roll)

the alternative is to add an attachment point to the front of the nosewheel, which will always point in the direction the wheels should roll, then allow the tug to attach to this point, but then you have some kinematics come into play and it gets very complicated (it has been tried)

on a positive note, my hangars are easily long enough to accomodate the G42-200, a whopping 135m long, and the enterance is 90m wide, so providing you can keep the wingspan to 80m, theres nothing to worry about there.

any models you can post will be awesome, i can get a better picture of the end product, so we're both on the same level

good luck!

---------- Post added at 08:51 PM ---------- Previous post was at 08:39 PM ----------

hang on, i just looked at the original schematic, and i figure that the wingspan is only about 45-50m anyway, so we're good, that leaves a rough wheelbase of 30-35m (?),

 

[Moach]

ok, well, the wingspan is not gonna be nowhere near that... should be just about the same as for the 100 model...

only that, with the wings folded up, the 200's can be parked a little more tightly still :hmm:

as for the tug, i reckon a basic UCGO solution may simply not be satisfactory... in order to properly steer the G42, something special should be coded along with the ship itself...


but i have also devised a way to make it simpler for me... a special tug, that once attached, can spin -around- the front gear, steering it without having to pull the ship forward...

i'll draw it up - hang on... :thumbup:

 

[Grover]

cant wait to see what you have in mind

 

[Moach]

well, this is what i thought of...

the idea is that the tug doesn't really "pull" the G42, it moves it by driving it's nose wheel instead...

when disconnected, the four sets of omni-wheels receive engine traction to move the tug around, then once latched to the gear, that traction gets applied on the locking hubs, so the tug's engine drives the ship's wheels :hmm:

with an independent drive for each wheel, the tug can spin them in different speeds or directions, making it steer... and in doing so, with it's free-spinning sets of omni-wheels, the tug rotates around it's own axis, allowing it to maneuver the G42 as if it was taxiing by itself


on the tugs roof, a service platform is mounted to allow access to the cabin by the hand-ladder on the gear strut - this makes for much simpler and faster attach-detach operations

whadda you think?

 

[edsupagood]

Wow something I haven't seen before. Very nice idea though, but will it have enough power to pull such enormous weights, it looks awfully small.

 

[Moach]

Wow something I haven't seen before. Very nice idea though, but will it have enough power to pull such enormous weights, it looks awfully small.

it should have some pull in it... the v-10 diesel engine takes up most of the front section (next to the driver's cab)

it's still not very fast, tho :lol:


and we can always make it bigger if we need to... it`s not like we`re taking it up to space as well

 

[Grover]

It has to be bigger i think, youd need at least a 25 litre diesel engine to pull a craft that size, and on an orbiter level, how will you achieve this, and how will it be controlled.

alternatley, you could give the rear wheels some drive, or make the main engines run without the afterburner, jet engines are quite efficient nowadays

 

[Moach]

i don't wanna have the main gears loaded with motors... that would be quite a binch of uneeded weight.... so that's a last-resort alternative...

i'm aware that a larger tug will be required... that mini-tug could probably be used to maneuver unladen ships around the ramp, but not beefy enough to haul a ready-to-go craft up to the runway...

i'll think of something larger

 

[Fabri91]

The tug looks great, but maybe you should reconsider giving one gear (nose gear maybe, so you have only one motor) an electric motor which is powered by the APU. Airbus is actually planning to introduce such a feature in a few years time.

 

[Grover]

well, leave that for now, just get the craft itself working

and i have some pointers, in case you were going to simply build on top of the old G42:


make sure that the fuel tank and engines are defined so orbiter can see them, else all auto-burn MFDs and such will not function

definatley allow the jet engine to function without the afterburner/rocket exhaust, that alone would be suitable for moving around the taxiway, remember, modern jet engines are very efficient, and especially so when compared to rocket engines

there was a slight bug in the old G42 where the control surfaces moved by themselves, without input, and i think it also affected control

in the new windshield visor, dont put windows in it, you dont need to see what youre doing once youre above 1k, and when you come in to land, you could potentially do it without looking outside the window anyway, but below supersonic speeds, the sindwhield should hold up without the visor anyway

PUT ENGINE SOUNDS IN

and most importantly, put the 3 letter abbreviations onto the MFD buttons, so you know what youre pressing

i know it was WIP, and so you probably would have put some of these features in, but i just thought id make sure.

im off now to texture my hangars, laters!

 

[Moach]

well, leave that for now, just get the craft itself working

and i have some pointers, in case you were going to simply build on top of the old G42:


make sure that the fuel tank and engines are defined so orbiter can see them, else all auto-burn MFDs and such will not function

definatley allow the jet engine to function without the afterburner/rocket exhaust, that alone would be suitable for moving around the taxiway, remember, modern jet engines are very efficient, and especially so when compared to rocket engines

there was a slight bug in the old G42 where the control surfaces moved by themselves, without input, and i think it also affected control

in the new windshield visor, dont put windows in it, you dont need to see what youre doing once youre above 1k, and when you come in to land, you could potentially do it without looking outside the window anyway, but below supersonic speeds, the sindwhield should hold up without the visor anyway

PUT ENGINE SOUNDS IN

and most importantly, put the 3 letter abbreviations onto the MFD buttons, so you know what youre pressing

i know it was WIP, and so you probably would have put some of these features in, but i just thought id make sure.

im off now to texture my hangars, laters!

well, most of what you said i already had planned, specially the MFD buttons and all :thumbup:

engine sounds were already in... could i have forgotten to add them in the zip?

as for the visor not having windows... not sure about that... the G42 is suposed to be capable of flying supersonic ferry flights on its own - removing the need for a plane large enough to piggyback a An225-sized piece of hardware
likewise, the G42 can fly in such "economy mode" for a while, until it reaches the desired inclination for launch...

this does imply a need for engines that can run without afterburner, as you said - but also means that the pilots should be able to see -something- out of the visor, since they might as well be flying over controlled airspace...

either way... the visor windows are small, just enough to not leave the pilots with a drastically reduced situational awareness (what if some avionics go "pop")


you mentioned the G42-100 had a "bug"... well the control surfaces move by themselves because of the fly-by-wire system... it's not a bug - it's a feature :rofl:
and it's only a visual thing.... the so called "fly-by-wire" is represented in-sim by an un-naturally stable handling of the craft... (if ever you could call a delta flying-wing with no rudders "stable" :lol

well, the G42-200 has a rudder (for now) and with the longer tail boom should prove infinitely more stable than the -100 variant... allowing for a much less aggressive stability augmentation system

well, back to modelling... the ship isn't gonna build itself...

i show you guys how it's going in a bit... it's just starting to look like something :thumbup:

 

[Grover]

you underestimate the power of the VOR, there are thousands around the globe, and even aircraft can navigate a precice route without the pilot even needing a window except for takeoff and landing and taxi.

id suggest having no windows, and it is slightly more realistic, any glass will break easier than any airframe/heat retardant material used in spacecraft construction, but i suppose if we are actually doing an SSTO craft then we can be a little leniant on the realism

and heres my plan for afterburner-less mode (similar to the F-18 hornet system)
throttle =0% idle, engine doesnt produce enough thrust to overcome inertia
throttle=5%-75% jet turbines work at increasing levels, reaching their peak at 75% throttle
throttle=75%-100% afterburner 'kicks in', in variable stages up to maximum power, though the increase in throttle only affects the afterburner, not the turbines in any way

this allows you to taxi (who goes above 75% throttle on the taxiway) and even conduct the early takeoff without using the afterburner, which i believe would work better at speed anyway due to the inherent design of the exhaust, yet you would be easily able to hit the afterburner by nudging your throttle a little

of course, you may have a better idea, but this is a suggestion that is proven by trial to work well.

cant wait to see your model, i genuinley believe that this could chalenge the XR2 for style, and maybe even functionality coolness if you manage all that you plan

good luck!

 

[Moach]

(...)
id suggest having no windows, and it is slightly more realistic, any glass will break easier than any airframe/heat retardant material used in spacecraft construction (...)

oh, that ain't glass :lol:


the visor windows are supposedly made of translucent ceramics ([ame="http://en.wikipedia.org/wiki/Transparent_ceramics"]yes that is a real thing[/ame]) h::speakcool:

which should be unbelievably expensive, another reason for them to be small


as for the afterburners, i was actually thinking a switch should be used... like the "reheat" switches on the concorde.... and when on, above 75% of throttle, the afterburners are engaged :thumbup:


back to modelling...

 

[Grover]

Awesome, i see your logic. Cant wait to see the model.

 

[Moach]

without further ado....

first run of the WIP 3d model :thumbup:

that's all i have so far... getting those curved areas right was -not- easy, i give you that! :lol:

i've not modelled the bottom yet, nor the rudder... oh well... let me get back to it

 

[jangofett287]

I've noted the wings taper down to a line at the front, just underneath the main body. You might want to rethink this, as the stresses may easily rip that bit off at mach 20-odd

 

[Moach]

I've noted the wings taper down to a line at the front, just underneath the main body. You might want to rethink this, as the stresses may easily rip that bit off at mach 20-odd

hmm, it looks that way because of the angle that screenwhot was taken from...
it doesn't taper to a line, if you look at the blueprints, you may notice that in fact, the wings stop tapering and form a horizontal wedge, and do not blend down to the fuselage at that point...

the fusalage then smoothly wedges into the blended-wing section a few meters back.... it's like the intake on an f-16, to an extent

and at the front of the horizontal-wedge formed between the wings, there'll be a lip-flap, which adapts to the intake shock so it's directed towards the bottom of the intake, which, also has a slat of it's own...