Project ArrowHead-Reusable SSTO (Multistage to get to the moon)
- Thread starter Hurricane
- Start date
Revision No.1
Woah, it's been months. Well, As you can see I have completely stopped developing the Arrowhead. I am now in the process of revising it (now with actual realism in mind-I shall make no crude guesses this time). I will also be using X-Plane to partially confirm the realism of the craft. I think I will also find some way to export X-Plane's flight model to Orbiter to make it realistic. Maybe a BET/wind tunnel module powering the flight model of the spacecraft. I will try to see if I can also make use of X-Space's more elaborate super- and hypersonic physics, as well as its non-atmospheric model.
I haven't yet managed to get the time to learn C++, I hope I'll get the time to later this winter.
The second revision is currently on paper only, and we won't see it anytime soon in 3D because my school finally managed to overload me :uhh:. I also have some other X-Plane projects underway, which will hopefully provide the infrastructure for beginning the work over the Arrowhead.
A bit of what I have in mind, in short:
-Revision #1 will have three main engines: 2 liquid fuel rockets and a single variable geometry scramjet engine, functional at about Mach 4 to about Mach 16.5.
-It will be about the size of the Space Shuttle Orbiter.
-It will have a crew of 2-5 and a passenger capacity of 9-12. Total people capacity is 14, twice than that of the space shuttle. I'm not sure how scientifically correct this is, so I will put a question mark on it for now: [:idk:]
-Its payload bay (if I will make one) is projected to be 8.75m long by 3.75m wide by 3.25 deep. Smaller than the space shuttle's, but it doesn't really matter nowadays.
-I think it will still be a SSTO, albeit it will be rather incapable-ISS only. To add moon capability you'll have to use either a single stage or a 2-stage rocket I like to call the ArrowShaft (which together with the Arrowhead makes up an entire arrow! -See what I did there? :thumbup
. I haven't decided on details yet, other than the fact that it will disable the scramjet engine (which I suppose won't be needed anyway).
~Stay tuned for more! I shall return here every few days, reporting what progress I have made. In the meantime, enjoy this emoticon of a smiley worshiping a UFO:
[
]
(Once I'm finished with my X-Plane payware project, I will have the time and resources to put into the Arrowhead. But it's a long way to go, so hold on to your DGs/XRs/Orbiters for now!)
~Best regards, Oz.
---------- Post added 01-14-12 at 04:17 PM ---------- Previous post was 01-13-12 at 08:02 PM ----------
Any feedback would be appreciated guys!
Now, I have update No.1 about Revision No.1:
-First of all, I am glad to announce that the basic layout is orthographically portrayed in my notebook. After a lot of eraser residue, it looks really nice.
-I have measured and learned that the over-the-nose visibility is about 30 degrees. That's sick--more than most fighter jets and more than the space shuttle (not sure about the DG though). You may wonder why it is important, but you might find it useful in some CVFR atmospheric flight (wait, does Mach 17 at 65 Km count as CVFR?). But you can fly at 10 Km at Mach 3.5-5, recognizing mountains and continents (E.G. serious landmarks) for your navigation. You may, however, find it REALLY useful when making VTOL landings on the moon. It is also just nice to have such a wide field of view! :tiphat:
-I haven't really considered overall capacity, but I did some numbers and discovered some facts about its gross living space:
1. It is about 5.19 meters long.
2.The cabin's mean width is 3 meters.
3. The cabin's mean height is about 3 meters.
4. Assuming a rather cubical shape for the cabin-for the sake of primary simplicity-the cabin's volume is 46.71 cubic meters. Less than the space shuttle's but bigger than the deltaglider's. The cabin is also cramped before that [rather unnecessary] cargo bay, which may shrink in the future to accommodate a larger cabin, or thoroughly disappear to also facilitate a larger fuel tank. Or I may push it further backwards, Or I can make a crawlspace (wait, can you even crawl in space?) below or aside the cargo bay [assuming asymmetry], leading from the flight deck to the living area. It is still undetermined, I will decide what I want to do with the cargo bay and the cabin further down the road.
-It has a 'cranked arrow delta wing', much like the space shuttle (and the original version of it) to facilitate high-alpha re-entries, however I will use X-Space to test if it is skip-reentry-capable, and in that case it might also be able to use the scramjet to fly a combination of the two reentry types-a straightforward, non-skipping reentry that is done at a low alpha, using the scramjet to gradually decelerate during the 65-15 Km phase of the reentry.
I am constantly evaluating new features and making necessary changes to the airframe so that when I will actually have the time to sit several hours a day and do it, it will be rather straightforward.
~Stay tuned as more details will come. I am currently looking for decent ways to connect it to the Arrowshaft. After all it will have to withstand tremendous stresses during the ascent.
~Best regards, Oz.
Woah, it's been months. Well, As you can see I have completely stopped developing the Arrowhead. I am now in the process of revising it (now with actual realism in mind-I shall make no crude guesses this time). I will also be using X-Plane to partially confirm the realism of the craft. I think I will also find some way to export X-Plane's flight model to Orbiter to make it realistic. Maybe a BET/wind tunnel module powering the flight model of the spacecraft. I will try to see if I can also make use of X-Space's more elaborate super- and hypersonic physics, as well as its non-atmospheric model.
I haven't yet managed to get the time to learn C++, I hope I'll get the time to later this winter.
The second revision is currently on paper only, and we won't see it anytime soon in 3D because my school finally managed to overload me :uhh:. I also have some other X-Plane projects underway, which will hopefully provide the infrastructure for beginning the work over the Arrowhead.
A bit of what I have in mind, in short:
-Revision #1 will have three main engines: 2 liquid fuel rockets and a single variable geometry scramjet engine, functional at about Mach 4 to about Mach 16.5.
-It will be about the size of the Space Shuttle Orbiter.
-It will have a crew of 2-5 and a passenger capacity of 9-12. Total people capacity is 14, twice than that of the space shuttle. I'm not sure how scientifically correct this is, so I will put a question mark on it for now: [:idk:]
-Its payload bay (if I will make one) is projected to be 8.75m long by 3.75m wide by 3.25 deep. Smaller than the space shuttle's, but it doesn't really matter nowadays.
-I think it will still be a SSTO, albeit it will be rather incapable-ISS only. To add moon capability you'll have to use either a single stage or a 2-stage rocket I like to call the ArrowShaft (which together with the Arrowhead makes up an entire arrow! -See what I did there? :thumbup
. I haven't decided on details yet, other than the fact that it will disable the scramjet engine (which I suppose won't be needed anyway).~Stay tuned for more! I shall return here every few days, reporting what progress I have made. In the meantime, enjoy this emoticon of a smiley worshiping a UFO:
[](Once I'm finished with my X-Plane payware project, I will have the time and resources to put into the Arrowhead. But it's a long way to go, so hold on to your DGs/XRs/Orbiters for now!)
~Best regards, Oz.
---------- Post added 01-14-12 at 04:17 PM ---------- Previous post was 01-13-12 at 08:02 PM ----------
Any feedback would be appreciated guys!
Now, I have update No.1 about Revision No.1:
-First of all, I am glad to announce that the basic layout is orthographically portrayed in my notebook. After a lot of eraser residue, it looks really nice.
-I have measured and learned that the over-the-nose visibility is about 30 degrees. That's sick--more than most fighter jets and more than the space shuttle (not sure about the DG though). You may wonder why it is important, but you might find it useful in some CVFR atmospheric flight (wait, does Mach 17 at 65 Km count as CVFR?
). But you can fly at 10 Km at Mach 3.5-5, recognizing mountains and continents (E.G. serious landmarks) for your navigation. You may, however, find it REALLY useful when making VTOL landings on the moon. It is also just nice to have such a wide field of view! :tiphat:-I haven't really considered overall capacity, but I did some numbers and discovered some facts about its gross living space:
1. It is about 5.19 meters long.
2.The cabin's mean width is 3 meters.
3. The cabin's mean height is about 3 meters.
4. Assuming a rather cubical shape for the cabin-for the sake of primary simplicity-the cabin's volume is 46.71 cubic meters. Less than the space shuttle's but bigger than the deltaglider's. The cabin is also cramped before that [rather unnecessary] cargo bay, which may shrink in the future to accommodate a larger cabin, or thoroughly disappear to also facilitate a larger fuel tank. Or I may push it further backwards, Or I can make a crawlspace (wait, can you even crawl in space?) below or aside the cargo bay [assuming asymmetry], leading from the flight deck to the living area. It is still undetermined, I will decide what I want to do with the cargo bay and the cabin further down the road.
-It has a 'cranked arrow delta wing', much like the space shuttle (and the original version of it) to facilitate high-alpha re-entries, however I will use X-Space to test if it is skip-reentry-capable, and in that case it might also be able to use the scramjet to fly a combination of the two reentry types-a straightforward, non-skipping reentry that is done at a low alpha, using the scramjet to gradually decelerate during the 65-15 Km phase of the reentry.
I am constantly evaluating new features and making necessary changes to the airframe so that when I will actually have the time to sit several hours a day and do it, it will be rather straightforward.
~Stay tuned as more details will come. I am currently looking for decent ways to connect it to the Arrowshaft. After all it will have to withstand tremendous stresses during the ascent.
~Best regards, Oz.
Last edited:
Okay, time for some more updates, as apparently I have more time than I thought:
-A size mismatch between the top and size views meant that my scale is compromised. Even though I elongated the side view by what was 2.3 meters on the previous scale, the cabin is now smaller (?!). My temporary solution to this is by making the craft longer at exactly 35 meters instead of 30 meters. I think I'll keep up with this size because with that scale the cabin has the volume of about 69.115 cubic meters. Assuming a double-deck cabin it has 2 decks exactly 2 meters high each.
Being 5.5 meters long, the new cabin has 4 rows of seats. 4 rows times 4 seats means 16 passengers. If there are folks here with the more educated mind, please refine that number. Cockpit crew I suppose should be 3-4, so the cabin will be cramped by 20 people. Again, PLEASE refine my numbers!
-I think I found a way to attach it to the Arrowshaft, by using some umbilical doors on the sides which will reveal the mounting points for the boosters. You'll get it better as new screenies begin to flow.
-In the meantime the payload bay remains as it was, with its size on the new scale being 7.5m long by 3.75 meters tall by 4.375 meters wide.
If everything goes as planned, flight-testing in X-Plane should begin in the upcoming 6 weeks. If not, well...:blush:
~Best regards, Oz.
-A size mismatch between the top and size views meant that my scale is compromised. Even though I elongated the side view by what was 2.3 meters on the previous scale, the cabin is now smaller (?!). My temporary solution to this is by making the craft longer at exactly 35 meters instead of 30 meters. I think I'll keep up with this size because with that scale the cabin has the volume of about 69.115 cubic meters. Assuming a double-deck cabin it has 2 decks exactly 2 meters high each.
Being 5.5 meters long, the new cabin has 4 rows of seats. 4 rows times 4 seats means 16 passengers. If there are folks here with the more educated mind, please refine that number. Cockpit crew I suppose should be 3-4, so the cabin will be cramped by 20 people. Again, PLEASE refine my numbers!
-I think I found a way to attach it to the Arrowshaft, by using some umbilical doors on the sides which will reveal the mounting points for the boosters. You'll get it better as new screenies begin to flow.
-In the meantime the payload bay remains as it was, with its size on the new scale being 7.5m long by 3.75 meters tall by 4.375 meters wide.
If everything goes as planned, flight-testing in X-Plane should begin in the upcoming 6 weeks. If not, well...:blush:
~Best regards, Oz.
Okay, third update's up:
This one is short. As I get closer and closer to finalizing the design, I have less and less things to update, so here it goes:
-The engine I decided to use is the RS-68, rated at 3.37Mn, unless noted different, because after all, it runs on liquid hydrogen, which has a very low density. Should I find another single-nozzle engine capable of generating more than 3 Mn, I think I will use that one.
-I haven't yet calculated mass and fuel load, I will do that when I will start making it.
-I have decided that I also want a cargo-only variant, which I have started to [mentally] design- it will be wider and slightly taller, and most of the cabin will give way for a bigger payload bay.
-Edit: I couldn't stand but make a coarse calculation, that revealed that I need 310 times the amount of space I had (make that 250, since I could also put fuel in the wings, didn't calculate them too). That was unbearable. I had the idea of drawing air in from the SCRamjet intake, which will reduce about 65% of the mass I'm supposed to carry, regarding that I still have to carry SOME O2 for Mach<4 flight and spaceflight. After some more arbitrary calculations, it showed that I still need 108.5 time more than I got. All that is without the scramjet fuel calculations and hopefully it will get down along time. Hang on; more updates soon.
-Edit #2: I promised, and updated again. If I use the scramjet from Mach 3 to Mach 17, then I only need 56.96 times than what I have. I will recalculate how much I REALLY have in the upcoming days, after I'll get the model to X-Plane (with the correct airfoils and all) and update the drawings for easier calculation. That includes the wings and the fuselage. In the worst case scenario, I shall create more room by removing some cabin and payload bay space, and making "backpack tanks" (the IAF name for the F-16 conformal fuel tanks), which will eliminate some lift and give us more room for fuel. A LOT more. STAY TUNED! I promise to update this thread and find the solution to my SSTO problem. I could also use drop-tanks on the heat shield, but that will defeat the SSTO title, so I think.
Take care, Oz.
~Oz out for now, hail the probe!
---------- Post added 01-17-12 at 04:19 PM ---------- Previous post was 01-16-12 at 06:22 PM ----------
So I was trying to get some sleep last night, and then I remembered that I saw the F-1 engine, which was rated at more than 6 Mn. Well, I though that I could use a single engine rated somewhere near the F-1. Along with the scramjet, I have a pretty darn good spacecraft, with a strong engine. A single engine consumes half the fuel 2 engines do, and so I have better fuel economy. Hmm.... Maybe, since the scramjet is centerline, and the two rockets are on pods, and transfering to a single-engine layout will force me to put it on the centerline, how about an extreme variant of the SABRE engine?
That might just work! :thumbup:
Okay, another update's up!
I did some finer calculations in an excel spreadsheet, that have found that carrying almost no oxygen, I have 1/27 of what I need, only in the fuselage. I have started designing a scramjet/rocket hybrid where both engines use the same nozzle. That'll also allow me to use pressure difference between the nozzle and the scramjet intake to really saturate the propellant, allowing me to take a lower ratio of LOX. I am no propulsion expert, but I think it could work. I have also found yet another benefit to a single engine layout: the pods, used to mount the rocket engines before the single engine revision can be lengthened and serve a double purpose, both as anti-shock bodies reducing supersonic drag and it could also serve as a fuel tank. Hmmm...
I don't want to make another revision to it, so I think I will find some elaborate way to enlarge the inside of it. Now, it's almost like an asymptote: the closer I get to the fuel loadout, the harder it gets to keep going.
I am also thinking to use weight-reducing materials, so that the fuel economy will increase further. If that won't work, then it's time for yet another revision. I want to make it a SSTO, and I know it's gonna be HARD. I thought of a really nice way to reduce weight and thereby increase fuel efficiency, but it's already implemented to the airframe, albeit in a very primitive way. I am considering transferring to another scale system, which will make it bigger overall.
I keep delaying this question, is this possible to compress the fuel, say, so that it takes up 80% of its original volume?
Another solution I am considering is using near-future rocket engines, with an Isp of, let's say about 600. Not a great contribution, but every little detail counts!
To sum up, I am on the verge of revision No.2 (I knew I was to revise it several more times, that's why I numbered the revisions in the first place! :thumbup: ).
Revision number 2 is to be longer, wider and taller. It will have a larger cargo bay, and a better propulsion system. It is to be as realistic as possible, in the bounds of what's possible. It will be a true, native SSTO with multistage capabilities to get to the moon. I want it to be as small as possible, but I know this won't happen with today's technology. Just hang on to something while I think about what to do next. The ArrowHead will prevail! (;
Over 'n out, Oz.
[Even after this long brain dump, I still have a lot of question marks and lit lamps in my head. Please answer the questions I asked and help me bring it one step further.]
Oh, and by the way, hail the probe!
This one is short. As I get closer and closer to finalizing the design, I have less and less things to update, so here it goes:
-The engine I decided to use is the RS-68, rated at 3.37Mn, unless noted different, because after all, it runs on liquid hydrogen, which has a very low density. Should I find another single-nozzle engine capable of generating more than 3 Mn, I think I will use that one.
-I haven't yet calculated mass and fuel load, I will do that when I will start making it.
-I have decided that I also want a cargo-only variant, which I have started to [mentally] design- it will be wider and slightly taller, and most of the cabin will give way for a bigger payload bay.
-Edit: I couldn't stand but make a coarse calculation, that revealed that I need 310 times the amount of space I had (make that 250, since I could also put fuel in the wings, didn't calculate them too). That was unbearable. I had the idea of drawing air in from the SCRamjet intake, which will reduce about 65% of the mass I'm supposed to carry, regarding that I still have to carry SOME O2 for Mach<4 flight and spaceflight. After some more arbitrary calculations, it showed that I still need 108.5 time more than I got. All that is without the scramjet fuel calculations and hopefully it will get down along time. Hang on; more updates soon.
-Edit #2: I promised, and updated again. If I use the scramjet from Mach 3 to Mach 17, then I only need 56.96 times than what I have. I will recalculate how much I REALLY have in the upcoming days, after I'll get the model to X-Plane (with the correct airfoils and all) and update the drawings for easier calculation. That includes the wings and the fuselage. In the worst case scenario, I shall create more room by removing some cabin and payload bay space, and making "backpack tanks" (the IAF name for the F-16 conformal fuel tanks), which will eliminate some lift and give us more room for fuel. A LOT more. STAY TUNED! I promise to update this thread and find the solution to my SSTO problem. I could also use drop-tanks on the heat shield, but that will defeat the SSTO title, so I think.
Take care, Oz.
~Oz out for now, hail the probe!
---------- Post added 01-17-12 at 04:19 PM ---------- Previous post was 01-16-12 at 06:22 PM ----------
So I was trying to get some sleep last night, and then I remembered that I saw the F-1 engine, which was rated at more than 6 Mn. Well, I though that I could use a single engine rated somewhere near the F-1. Along with the scramjet, I have a pretty darn good spacecraft, with a strong engine. A single engine consumes half the fuel 2 engines do, and so I have better fuel economy. Hmm.... Maybe, since the scramjet is centerline, and the two rockets are on pods, and transfering to a single-engine layout will force me to put it on the centerline, how about an extreme variant of the SABRE engine?
That might just work! :thumbup:
Okay, another update's up!
I did some finer calculations in an excel spreadsheet, that have found that carrying almost no oxygen, I have 1/27 of what I need, only in the fuselage. I have started designing a scramjet/rocket hybrid where both engines use the same nozzle. That'll also allow me to use pressure difference between the nozzle and the scramjet intake to really saturate the propellant, allowing me to take a lower ratio of LOX. I am no propulsion expert, but I think it could work. I have also found yet another benefit to a single engine layout: the pods, used to mount the rocket engines before the single engine revision can be lengthened and serve a double purpose, both as anti-shock bodies reducing supersonic drag and it could also serve as a fuel tank. Hmmm...
I don't want to make another revision to it, so I think I will find some elaborate way to enlarge the inside of it. Now, it's almost like an asymptote: the closer I get to the fuel loadout, the harder it gets to keep going.
I am also thinking to use weight-reducing materials, so that the fuel economy will increase further. If that won't work, then it's time for yet another revision. I want to make it a SSTO, and I know it's gonna be HARD. I thought of a really nice way to reduce weight and thereby increase fuel efficiency, but it's already implemented to the airframe, albeit in a very primitive way. I am considering transferring to another scale system, which will make it bigger overall.
I keep delaying this question, is this possible to compress the fuel, say, so that it takes up 80% of its original volume?
Another solution I am considering is using near-future rocket engines, with an Isp of, let's say about 600. Not a great contribution, but every little detail counts!
To sum up, I am on the verge of revision No.2 (I knew I was to revise it several more times, that's why I numbered the revisions in the first place! :thumbup: ).
Revision number 2 is to be longer, wider and taller. It will have a larger cargo bay, and a better propulsion system. It is to be as realistic as possible, in the bounds of what's possible. It will be a true, native SSTO with multistage capabilities to get to the moon. I want it to be as small as possible, but I know this won't happen with today's technology. Just hang on to something while I think about what to do next. The ArrowHead will prevail! (;
Over 'n out, Oz.
[Even after this long brain dump, I still have a lot of question marks and lit lamps in my head. Please answer the questions I asked and help me bring it one step further.]
Oh, and by the way, hail the probe!
Last edited:
You can't compress liquids - you can slightly inrease density by lowering temperature but then you have add insulation for the tanks
Low density generally isn't an issue, the higher ISP of LH2/LOX engines outweighs it by far.
It is an issue if your tank volume is limited though. Perhaps you could consider a tripropellant engine?
The RD-701 for the MAKS program had two modes, one burning LH2, LOX, and kerosene, and one just burning hydrolox (with a claimed ISP of 460 seconds in hydrolox-only mode). By using tripropellant, T/W of the engine can be increased, and the total volume needed for propellant can be reduced while still retaining a relatively high ISP (for the RD-701, 415 seconds in tripropellant mode, and even higher in hydrolox only mode).
The RD-701 was also supposed to have a sea level thrust of over 3 MN, which fits in well with your requirements. And a maximum ISP of 460 (as opposed to the RS-68's 409, which is quite appalling for an SSTO) will sure help, too.
Since the rocket equation is exponential, it could help a lot... but no engine is going to reach 600 seconds of ISP with near-future developments. It's out of the range of the energy that chemical propellants can provide (or at least practical propellants, i.e. without having to include nasties such as fluorine, etc).
You can go higher if you use nuclear propulsion, but nuclear propulsion is a total pain.
You can prechill the propellants to increase their density though. See [ame="http://en.wikipedia.org/wiki/Slush_hydrogen"]slush hydrogen[/ame].
Okay, so several things covered: An Isp of 600 isn't rational.
I could add a second scramjet. Could that contribute?
So if using LOX and liquid hydrogen (or RP-1, haven't fully settled on an engine yet), I am basically having the propellant as dense as it could get, correct?
Edit: Well I forgot to bring about this day's update, so here it goes:
A miscalculation meant that I used a much higher number than I should have for its mass (I compared the size to mass of real proposed SSTOs for the new number). Now here it goes: if I take almost no LOX, and enough scramjet fuel to get from Mach 3 to Mach 17, then I have 1/11 from what I need, that done assuming that the Ve is the sum of the Ve's of both engines. If not, then I have 1/24 from what I need. Bear in mind that all that is with the initial volume calculation, and that the volume is likely to increase, especially should I choose to revise it yet another time. Quite a change from 1/310, huh?
[please notify me whether the equation uses the sum or not! :thumbup:]
So revision no.2 is right around the corner. I know I want to keep the general shape of it because it is more than satisfactory. I will make it longer, wider and taller, and perhaps find a better engine arrangement, so that I will, in fact, be able to carry all of the fuel to become a SSTO.
[Just as a remark, when I say that I carry almost no LOX, I mean that I only carry 40% of what the tsiokolvsky equation says I should be carrying- as the LOX to fuel ratio is 2.67 to 1, that leaves me with more than enough LOX, the rest coming from the atmosphere through the scramjet intake or through dedicated intakes. (Or perhaps I could use intakes that have an intake fan to be able to use outside oxygen at Mach<3 flight?)]
~Oz out for now, take care and happy Orbiting!
I could add a second scramjet. Could that contribute?
So if using LOX and liquid hydrogen (or RP-1, haven't fully settled on an engine yet), I am basically having the propellant as dense as it could get, correct?
Edit: Well I forgot to bring about this day's update, so here it goes:
A miscalculation meant that I used a much higher number than I should have for its mass (I compared the size to mass of real proposed SSTOs for the new number). Now here it goes: if I take almost no LOX, and enough scramjet fuel to get from Mach 3 to Mach 17, then I have 1/11 from what I need, that done assuming that the Ve is the sum of the Ve's of both engines. If not, then I have 1/24 from what I need. Bear in mind that all that is with the initial volume calculation, and that the volume is likely to increase, especially should I choose to revise it yet another time. Quite a change from 1/310, huh?
[please notify me whether the equation uses the sum or not! :thumbup:]
So revision no.2 is right around the corner. I know I want to keep the general shape of it because it is more than satisfactory. I will make it longer, wider and taller, and perhaps find a better engine arrangement, so that I will, in fact, be able to carry all of the fuel to become a SSTO.
[Just as a remark, when I say that I carry almost no LOX, I mean that I only carry 40% of what the tsiokolvsky equation says I should be carrying- as the LOX to fuel ratio is 2.67 to 1, that leaves me with more than enough LOX, the rest coming from the atmosphere through the scramjet intake or through dedicated intakes. (Or perhaps I could use intakes that have an intake fan to be able to use outside oxygen at Mach<3 flight?)]
~Oz out for now, take care and happy Orbiting!
Last edited:
Revision No. 2 is up!
Well, here comes revision No.2:
It was elongated by 10m, and the pods that contain the rockets are now longer (WAY longer!). This make for more room for fuel. And about the same drag, since it is two long pods. I also roughly calculated the amount of fuel in the wings. Each wing contains about 125 cubic meters of fuel. Well, there are some more areas I remember now, which could contribute. The fuel amount I can store now (assuming little oxygen) is roughly 1/6.8 of what I need to get to the moon. More numbers soon! (I am determined to stay with this revision, since I already am sick of revision! ><)
Edit: Okay, I recalculated the wings and now I see each wing holds about 343 cubic meters of fuel. I also calculated some more areas and now it turns out that I am closer than ever: I have 1/5.32 of what I need to get to LEO with the new configuration. [Told y'all that it's almost like an asymptote!]
Any ideas where I could find some more places to put some fuel without yet another revision, or any idea for a higher Isp/any other way of getting to orbit without yet another redesgin?
~Take care, Oz. :tiphat:
Well, here comes revision No.2:
It was elongated by 10m, and the pods that contain the rockets are now longer (WAY longer!). This make for more room for fuel. And about the same drag, since it is two long pods. I also roughly calculated the amount of fuel in the wings. Each wing contains about 125 cubic meters of fuel. Well, there are some more areas I remember now, which could contribute. The fuel amount I can store now (assuming little oxygen) is roughly 1/6.8 of what I need to get to the moon. More numbers soon! (I am determined to stay with this revision, since I already am sick of revision! ><)
Edit: Okay, I recalculated the wings and now I see each wing holds about 343 cubic meters of fuel. I also calculated some more areas and now it turns out that I am closer than ever: I have 1/5.32 of what I need to get to LEO with the new configuration. [Told y'all that it's almost like an asymptote!]
Any ideas where I could find some more places to put some fuel without yet another revision, or any idea for a higher Isp/any other way of getting to orbit without yet another redesgin?
~Take care, Oz. :tiphat:
Last edited:
You can make the propellant a bit denser if you chill it, though it depends on the propellant and obviously there are other constraints that come from the whole operation.
Also, if your application is dV critical, I would not sugges the F-1- it has a pretty low ISP. You might want to go for an engine like the RS-68- a staged combustion kerolox engine (the NK-33 and RD-17x family from the USSR/Russia are also staged combustion kerolox, and exist and have flown, however all but the RD-191 have multiple chambers).
Last edited:
I hear the SABRE engine has an enormous Isp at jet mode, how so?
And is it possible to incorporate into the Arrowhead by any mean?
~Thanks in avance!
Because works as a jet, of course.
By using the air as an oxidiser and working fluid, a jet engine is far more efficient than a rocket engine.
This article could be helpful.
It may be possible to incorperate the SABRE concept into Arrowhead, however if you want to get really serious about it, you will have to include all the operational constraints as well... which could get tricky.
Because works as a jet, of course.
By using the air as an oxidiser and working fluid, a jet engine is far more efficient than a rocket engine.
This article could be helpful.
It may be possible to incorperate the SABRE concept into Arrowhead, however if you want to get really serious about it, you will have to include all the operational constraints as well... which could get tricky.
So a weak jet engine has an enormous Isp, and an awesome jet engine has a low Isp. Completely understandable :facepalm:
Well, revision No. 2 isn't as successful as I thought it would be, I miscalculated (again) and now I have 1/8 (and that's with almost NO LOX >at all<!!) of what I need to get to LEO. And I'm already at 45 meters long!
beatheadI think I will go for the lifting body/blended wing body solution to the problem as it allows a higher internal capacity for a lower drag penalty. Now, one problem with that is that X-Plane doesn't model it well, and I have no other idea of where to get my aerodynamic data. And I want to be as realistic as possible. (Yeah, otherwise it wouldn't have been revised in the first place!)
Now there's one thing I don't get. The space shuttle has three SSMEs with an average Isp of about 407 seconds, that run on LH2/LOX, and the tank it carries has a volume of 2050.798 cubic meters and isn't by far bigger than itself, for both LH2 and LOX. The space shuttle carries 1,735,601 kg of fuel (including the SRBs) and weighs around 78,000 kg.
So how in the name of the probe does it get to LEO, and something prevents the Arrowhead from getting to LEO when the Arrowhead is lighter (by far-at 33,500 kg)?
(Oh, yeah and the Arrowhead has an internal volume of roughly 4,170 cubic meters.)
~Best Regards, Oz. :thumbup:
---------- Post added at 07:12 PM ---------- Previous post was at 02:28 PM ----------
Back to Revision No.1(.1)
Okay, here comes the most exciting update of them all:
-It turns out that I made a serious miscalculation all along, and now I realized that revision No.2 was in vain (well, not totally :thumbup
.So what do I mean? I mean that I had the room for the fuel all along and I simply made a mistake which led to a misconception. I only had to slightly elongate revision No.1 and voila! A true, awesome LEO SSTO. Cheers!
Now, I have some facts about payload:
-The effective payload mass is 5 tons, although with a small amount of passengers (or none at all-leaving only the crew)- it could take up to six tons.
-Empty mass is 33,500 kg, and with a full cabin it could take about 4-4.5 tons to LEO.
Now, remember I wanted to make a very big version of it for big cargos? Well, revision 2 turns out to be JUST for that. Its enormous volume allows it to take an awesome amount of cargo to LEO. But the cargo Arrowhead will only be able to go to LEO, being too large to mount on any rocket, and I'm not going to design a second Arrowshaft anytime soon.
~Over and out, Oz. Following the recent success in making the Arrowhead a true SSTO, I am putting this thread on hold. Feel free to continue the discussions however. When I'll have the free time to learn C++, I'll start making it for X-Plane to verify it and procure the flight model. Then I'll write a module to port the aerodynamic data over to Orbiter and the .dll itself.
[Take care and hail the probe!
]
Last edited:
Okay, I thought to give you a sneak-peek at how it looks:
As you can see, it is ArrowHead
The gap between the two aft wings-this is where the Arrowshaft comes in. The two dints in the fuselage immediately to the fore of it - that's where the umbilical doors for the Arrowshaft are, this is essentially the "port to the moon" for this spacecraft.
There's not much left to explain, so - enjoy!
~Oz. :tiphat:
--------------Addition:------------------
I was wondering about the shape of the nose... Some friends of mine told me that the cockpit should be pushed backwards. Now, I don't know why and how to do this, and what the physical explanation behind this is.
Any elaboration would be thanked!
As you can see, it is ArrowHead
The gap between the two aft wings-this is where the Arrowshaft comes in. The two dints in the fuselage immediately to the fore of it - that's where the umbilical doors for the Arrowshaft are, this is essentially the "port to the moon" for this spacecraft.
There's not much left to explain, so - enjoy!
~Oz. :tiphat:
--------------Addition:------------------
I was wondering about the shape of the nose... Some friends of mine told me that the cockpit should be pushed backwards. Now, I don't know why and how to do this, and what the physical explanation behind this is.
Any elaboration would be thanked!
Last edited:
RGClark
Mathematician
- Joined
- Jan 27, 2010
- Messages
- 1,635
- Reaction score
- 1
- Points
- 36
- Location
- Philadelphia
- Website
- exoscientist.blogspot.com
I think at least 10% increase in density has been demonstrated by this method called subcooling. It might be possible to get in the range of 20% to 25% increase if you take it all the way down to the solid phase.
This could be doable if the propellant were stored as micro-or nanoparticles that could be pumped as liquids. It might also work to have it stored as a solid in the bulk of the tanks but with a heating system at the bottom that warmed it to the liquid phase at the bottom of the tank so that it could be pumped as liquid to the engines.
Bob Clark
MaverickSawyer
Acolyte of the Probe
Have you thought about using Methane as a fuel? It's nearly as high performance as hydrogen, it's "warmer" (about the same temps as LOX), and it's denser than LH2.
Hmm... :hmm: Any details about it? I'm too lazy to search for myself :lol:
Also, I've already settled on LH2+LOX for the main engines and JP-7 for the scram. I've also settled on the high-performance J-2X engine, it has an Isp of 448s! :thumbup:
Anyways, thanks for the input, I might consider it later on! :tiphat:
[Hurricane notes to self: research the possibility of liquid Methane. (Or not liquid? :shifty
]
MaverickSawyer
Acolyte of the Probe
Yeah, it's a lot like oxygen in terms of cryogenic specs, aside from the fact that it doesn't turn anything with the slightest combustibility into a firework! :lol:
Ok, I've decided that it's unfair to not keep you guys updated with the project's state.
So let's face it: the Arrow Launch System is sick. Very sick. It has always been, and unfortunately it's not going to change soon, if it even will change sometime.
The thing is, either due to my severe lack of knowledge, lack of initiative, any combination of the two or anything else, I unfortunately cannot get the Arrow Launch System (actually the Arrowhead namely, the actual flying part) to do what I dreamed it could. First came the fuel issues. Then balance issues. And some more issues I don't even remember! When I finally managed to tackle those, Israel went into war with Gaza and I was at the bombardment radius, not exactly a treat to work under such conditions.
When this all stopped, I forgot about the ALS. (Quite frankly I rediscovered my addiction to Combat Arms which drained me of all of my time, and I'm still trying to fend it off
)
So, a few days ago I sat down and took my folder where I keep all my designs. I glanced over at the Arrowhead, and thought that I should revise it yet another time. Without over looking at my previous calculations, I decided that they were not necessarily right, and definetly not optimal or realistic. So I decided to recalculate using a bit more realistic figures. So I reached some pretty nice figures, or so they seemed back then. And then I realized that they were wrong, because if I use a scramjet and my vehicle weighs around half as much as the STS, how on earth (or how in orbit if you will) could my vehicle take up half the fuel as the STS does?!
So I decided to ditch it again. I am still looking to return to it and make it work, but as of now there are at least 4 major barriers that block me from doing it:
1. I am stupid (lol
). I don't know anywhere near enough to tackle such a scale project, let alone FINISH it and RELEASE it.
2. Time is running out. As I am writing this post, I am nearing the end of the summer vacation, and on August 25th (thank you ministry of education) I will start the 11th grade, by far the hardest grade here in Israel, we have like 12 final tests, so not a lot of time. 12th grade is far easier, so I'll probably have time then to work on anything I want to, but I hope that my video game addiction won't resurge. After that I go to the military for at least 3 years, and then, well, who knows?!
3. My aforementioned addiction. I am still trying to fend it off, and should I have not been so addicted, I could at least have finished a few other projects and started to work on the ALS again. But I'm an addict, so I need to find ways to fight it.
4. My knowledge (or lack thereof) in C++ coding: Earlier this year I started learning C++ online as my first programming language (This is the tutorial if anyone's interested). I did pretty well, but then I reached OOP and for some reason stopped progressing. Probably my addiction but, meh. Anyways, I do not know anything NEAR enough to code even the simplest addon for Orbiter. The best I can do is probably take some other guy's code and put it in my addon, but I don't feel like it. I know that each addon contains several code files, models, textures, etc, but I don't know how to learn what each file does, I don't know how to learn the SDK really. I don't even know why, since Moach has said that the Orbiter SDK is one of the better-documented SDKs out there. Probably that relates to either the fact that I'm dumb or my lack of initiative. I don't even want to start trying, because when I did try no fruits came up.
So as you can see, sadly (at least sadly for me), the ALS is now officially suspended, as I have ceased any development work whatsoever and this is not going to change anytime soon.
Perhaps towards the 3rd semester I will have some more free time on my hands to return to my projects and finish them one by one. Right now my goal is to get rid of my addiction, and to really start doing productive stuff with myself. As to the ALS, I will redesign the entire system from the ground up, without missing anything. I know I'm capable, but every single time there's something else leeching on me and preventing me from achieving my goals.
Most likely I will [vaguely] remember the ALS and this post once the 11th grade storm settles, so I will probably reconsider my steps and start taking action in a few months.
Until then, stay safe, stay productive, don't get addicted to stuff and take care,
~Oz.
So let's face it: the Arrow Launch System is sick. Very sick. It has always been, and unfortunately it's not going to change soon, if it even will change sometime.
The thing is, either due to my severe lack of knowledge, lack of initiative, any combination of the two or anything else, I unfortunately cannot get the Arrow Launch System (actually the Arrowhead namely, the actual flying part) to do what I dreamed it could. First came the fuel issues. Then balance issues. And some more issues I don't even remember! When I finally managed to tackle those, Israel went into war with Gaza and I was at the bombardment radius, not exactly a treat to work under such conditions.
When this all stopped, I forgot about the ALS. (Quite frankly I rediscovered my addiction to Combat Arms which drained me of all of my time, and I'm still trying to fend it off
)So, a few days ago I sat down and took my folder where I keep all my designs. I glanced over at the Arrowhead, and thought that I should revise it yet another time. Without over looking at my previous calculations, I decided that they were not necessarily right, and definetly not optimal or realistic. So I decided to recalculate using a bit more realistic figures. So I reached some pretty nice figures, or so they seemed back then. And then I realized that they were wrong, because if I use a scramjet and my vehicle weighs around half as much as the STS, how on earth (or how in orbit if you will
) could my vehicle take up half the fuel as the STS does?!So I decided to ditch it again. I am still looking to return to it and make it work, but as of now there are at least 4 major barriers that block me from doing it:
1. I am stupid (lol
). I don't know anywhere near enough to tackle such a scale project, let alone FINISH it and RELEASE it.2. Time is running out. As I am writing this post, I am nearing the end of the summer vacation, and on August 25th (thank you ministry of education) I will start the 11th grade, by far the hardest grade here in Israel, we have like 12 final tests, so not a lot of time. 12th grade is far easier, so I'll probably have time then to work on anything I want to, but I hope that my video game addiction won't resurge. After that I go to the military for at least 3 years, and then, well, who knows?!
3. My aforementioned addiction. I am still trying to fend it off, and should I have not been so addicted, I could at least have finished a few other projects and started to work on the ALS again. But I'm an addict, so I need to find ways to fight it.
4. My knowledge (or lack thereof) in C++ coding: Earlier this year I started learning C++ online as my first programming language (This is the tutorial if anyone's interested). I did pretty well, but then I reached OOP and for some reason stopped progressing. Probably my addiction but, meh. Anyways, I do not know anything NEAR enough to code even the simplest addon for Orbiter. The best I can do is probably take some other guy's code and put it in my addon, but I don't feel like it. I know that each addon contains several code files, models, textures, etc, but I don't know how to learn what each file does, I don't know how to learn the SDK really. I don't even know why, since Moach has said that the Orbiter SDK is one of the better-documented SDKs out there. Probably that relates to either the fact that I'm dumb or my lack of initiative. I don't even want to start trying, because when I did try no fruits came up.
So as you can see, sadly (at least sadly for me), the ALS is now officially suspended, as I have ceased any development work whatsoever and this is not going to change anytime soon.
Perhaps towards the 3rd semester I will have some more free time on my hands to return to my projects and finish them one by one. Right now my goal is to get rid of my addiction, and to really start doing productive stuff with myself. As to the ALS, I will redesign the entire system from the ground up, without missing anything. I know I'm capable, but every single time there's something else leeching on me and preventing me from achieving my goals.
Most likely I will [vaguely] remember the ALS and this post once the 11th grade storm settles, so I will probably reconsider my steps and start taking action in a few months.
Until then, stay safe, stay productive, don't get addicted to stuff and take care,
~Oz.
Similar threads
