K-5A Attack ship: A tribute to the A-10 Warthog

[Fafnir_6]

Hello all,

Here is my latest attempt at a transatmospheric spacecraft, in this case, an attack ship that launches from a carrier in orbit to destroy things on a planet's surface. The K-5A was designed from the start as a tribute to the mighty A-10 Warthog so I must send my thanks to the people at Fairchild-Republic for inspiring me to complete this. As usual, constructive criticism is enthusiatically encouraged and I hope you like it.

Cheers,

Fafnir_6

[Coolhand]

looks cool, the fuselage shape reminds me of a frogfoot or maybe even an intruder.

does that gun run down the centreline? it looks like the mechanism needs more clearance between itself and the floor of the cockpit, i'd maybe drop that down and extend the front just a little, it would also make the profile a little more like the a10 rather than the other ac i mentioned.

Also, if you're going for realism then you might want to add some underslung engines, so the centre of thrust is aligned with the centre of mass. at the moment it looks like it'll be wanting to pitch itself down under power in space, because all the thrust is coming from above the centre of mass. You could ignore that effect (like the raptor from BSG) but it might be something to think about.

[Excalibur001]

looks pritty cool. nice work

[Ozylot]

Splendid!!!

[Falin]

I agree with coolhand here, that gun is right between the pilots legs, he don't need that added heat in there. I'd drop it down about 2-3 ft, give that pilot some love ;)

[Fafnir_6]

Hello all,

There are actually TWO forward-firing guns that pass by the cockpit on either side with the pilot sitting between the barrels, giving the K-5A a bit of a duck-face. Because they are mass drivers, with no gunpower munitions rounds, there is no need for the large amounts of armour in the munitions helix in the ammo drums like in the A-10 to protect against accidental munitions discharge in the drum. As such, the K-5A can pack more rounds in a similar sized volume. The assymetric thrust thing is a valid point, but I think you'll notice that I have angled the thrust nozzles of the engines upwards a la space shuttle to offset the assymetric thrust. Having the engines above and behind the wings is desirable for a ship like the K-5A and is the reason the A-10 looks like it does (good aginst battle damage and rough field landings).

Cheers and thanks for the constructive thoughts,

Fafnir_6

[Fafnir_6]

I've attached a diagram that illustrates how you can make assymetrical or off-centre engine mounts work in deep space. You just need to angle the thrust nozzles upwards such that the downward thrust of the bent up nozzles cancels the upward force of the odd engine mounting position. This is not the most efficient engine mounting scheme, but in some cases the effectiveness of the desired location of the engines warrants the sacrifice of a little thrust. ***Edit*** As described below, deep-space flight under power results in a characteristic nose-high attitude using this arrangement.

If you refer to the liner notes on the K-5A drawing, you will see that the K-5A did not have stellar deep-space performance, merely enough deep-space power to transit from the carrier to the atmosphere. This ***coupled with the angle-of-attack issues above***, necessitate the creation of a true deep-space attack ship in the AKM's inventory. The K-5A has limited up/down thrust vectoring to aid in thrust compensation, although it should not be required in most cases. The mounting of two guns is addressed in the liner notes as well.

Cheers,

Fafnir_6

[peragrin]

I love the A-10 warthog, And that ship looks mean enough to earn the title.

I would actually pull the pilots seat back a bit it's is too close to the nose. Otherwise can I have the hyper varient?

[Fafnir_6]

Yeah, I thought about pilot position quite a bit when I was designing the K-5A and there are some strong arguments in favour of moving the cockpit back a bit, but in the end, Those countless hours of ground-attack flight simming in the Fw190A/F and Ju87G in the IL-2 series of flight sims convinced me that awesome forward visibility is a good thing.

Cheers,

Fafnir_6

[Knight26]

Unfortunately Fafnir, that argument for off axis assymetric thrust doesn't hold water. No matter what angle you play those nozzles at you will have a pitching moment, or if you angle it through the center of mass you will always be flying with a nose high attitude, which will be a pain to compensate for. I would explain more but the baby is calling.

[Fafnir_6]

Unfortunately Fafnir, that argument for off axis assymetric thrust doesn't hold water. No matter what angle you play those nozzles at you will have a pitching moment, or if you angle it through the center of mass you will always be flying with a nose high attitude, which will be a pain to compensate for. I would explain more but the baby is calling.

Please do! I would assume that this is a question of balance and that limited range thrust vectoring could actually augment elevator control based on how far you act against the pitching. There must be a perfect nozzle angle to achieve straight flight. I would also guess that the rules would be different in and outside of gravity/atmosphere. The drawing I composed above was for weightless space flight, where Sir Isaac is king, not atmospheric flight. I would assume off center engine placement would be less of a problem in the atmosphere, given some of the stranger airplanes I have seen (that single-engined amphibian with the prop engine mounted on the top of the tail). I look forward to hearing what you have to say, given your occupation.

Cheers,

Fafnir_6

P.S. According to this article: A-10 Thunderbolt II - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/A-10_Thunderbolt_II) The real A-10 makes use of the technique I am suggesting (scroll down to the powerplant section).

[Knight26]

There are a few things to consider here for engine placement:

1) in atmo you have four basic forces of flight: Lift vs Weight, Thrust vs Drag. Off centerline engines on an airplane work because the pitching moment they generate is countered by a lift pitching moment in the opposite direction. The real A-10 for instance has its design optimized such that when in an attack posture that the plane does not need to be trimmed and will maintain its pitch with minimal input, remember it is a stick and rudder aircraft. Similarly on airliners they are optimized such that at cruising speed minimal trim is required to keep them straight and level.

2) Now go to space and barring the presence of a large gravitational body you have two forces, thrust and inertia. Thrust must always be utilized to overcome interia, Newton's laws.

Now, with your particular engine configuration you shouldn't have too much problem in atmo as you can optimize the design and trim the control surfaces to counter the off axis thrust vector and limit the moment arm. However in space, if you can direct your thrust such that it is through the center of mass of your craft then the ship will travel in a constant nose high attitude, so you will want to make provisions for your pilot to compensate for this. OF course this would make attack runs difficult and would present more of your fighters silouhette during runs.

In order to correct or compensate for this I suggest the following options:

1) Include some mechanism for moving the engines up and down, up for atmo flight and down along centerline for space flight.

2) Add a third engine:
2a) Have a third engine of same class slung at an appropriate distance underneath to overcome the pitching moment, you could make this engine detachable for atmospheric flight, but that is wasteful and makes going from atm-space or in reverse difficult.
2b) Again have a third engine, but have it be a smaller one, either on, or slightly below centerline with a thrust vectoring nozzle to help counter that pitching moment.

3) something to consider contrary to 99% of popular sci-fi you don't have to be under constant thrust you only thrust during manuevers, when changing that interia vector. So another option is to include a larger cluster of attitude control thrusters to counter the moment generated by thrusting those engines.

As for your space shuttle example, the SSME's are angled that way due to the external tank placement on the belly of the shuttle, those engines are not used in space. The OMS engines are used in space and when they are used the RCS thrusters always fire to counter the pitch over moment arm they generate.

[Fafnir_6]

Very interesting and thanks for the detailed post! A real-live flight test engineer is having input on one of my ships...just can't believe it :) . As it turns out, a nose-high attitude in deep-space flight is not a particularly big problem for the K-5A given the forward placement of the cockpit (thank god I chose that). Short thrusts can be controlled as described in your point #3 without any modifications, I think. In any case, off axis thrust in deep-space is doable, just with a few quirks ;). I'm very glad it will work well in the atmosphere with no problems.

In fact, I think this whole issue reinforces my aim to have the K-5A be somewhat of a penguin...ungainly but adequately functional in deep-space and then a graceful killing machine in its primary element, a planet's atmosphere. I so badly wanted the A-10 pattern to work in a trans-atmospheric application I may have been a little over-zealous in my defence of it. My apologies for that :).

In conclusion then, what you see here is the final interation of the K-5A and I will not be modifying it any further (Although I may do a K-5B with newer engines and a revised forward fuselage). It looks a little like a hovering hawk when under sustained power in deep-space. I suppose the K-5A pilot could activate the forward repulsorlifts in deep-space and fire the engines vectored straight back to achieve a level spaceflight attitude as well, options are always nice.

Your comments about the space shuttle were interesting as I was unaware that those canted nozzles were not used in space. You learn something new everyday.

Cheers and thanks for the hugely constructive criticism,

Fafnir_6

[Fafnir_6]

Here's a frontal view for the atmospheric flight attitude. This developmental drawing is derived from a relatively early plan of the K-5A so some details deviate from the final drawing and others are missing such as the movable hull plates covering the braking engines (these have been moved a bit following the discussion with knight26). The final iteration of the K-5A has the guns installed a little closer together and has three angled banks of thrusters covered by movable, ventral hull plates located along the centreline. I chose to cover these to reduce air resistance in atmospheric flight.

Cheers,

Fafnir_6

[bbzwbbzw]

Nice, nice design! I wouldn't change a thing personally but I'm all for the hand wave approach.

[Excalibur001]

how about giving te wings a slight kink, make it look like a dive bomber... you know, between the hull and the engines? could look cool.

[Parker Midwinter]

with that amount of anhedral to the wings, that thing would be VERY unstable... which would be a right bugger for doing an atmospheric attack run...

that said, i LOVE the design... it just looks like there' no question about what it's meant to do, and how good it is at doing it... just like the A-10

[TonTon]

Fafnir your style is recognizable and I really like your designs. I've only one criticism (more a request than a criticism actually) : it's just that you rarely draw other views of your ships. In my opinion there are some people here who just wait that to 3d model your ships. It could be very, very interesting.
I've read carefully the technical issues around your fighter, and I don't think it really matters. Keep up!

[ST-One]

This is an incredibly cool design. :)

[Fafnir_6]

Hello all,

I'm just checking up on this thread after a few months.

@Excalibur001: I assume you are wanting a sort of upside-down Stuka front profile? I'm afraid The K-5B will feature slightly less anhedral and engines buried in armoured tunnels in the wing roots. I don't have any plans for cranked wings at this time but things change, so who knows?

@Parker Midwinter: You probably raise a valid point with the anhedral, but I would point to aircraft such as the C-17 or An124 as examples of functional anhedral. I attached my wings at the top of the fuselage so that most of the mass of the ship is below the attachment point, hoping that this will provide some more stability. That said, I remember reading somewhere that an inherently instable design is needed for high degrees of manueverability, which I was looking for in my design. Whether or not I achieved a good balance between stability and manueverability is open to interpretation. As I noted above, the K-5B will feature slightly reduced anhedral and a different engine mounting position (mostly for deep-space performance concerns) that are likely to affect this aspect of the design. Also, I should probably note that this is my first real foray into the design of airplane-like craft so mistakes are likely to occur.

@TonTon: See reply #14. Several people have already posted some 3D renderings of my work on this site. Notable examples being Berticus with a wonderfully detailed rendition of the LCV-2A corvette (posted before the great crash of May, 2006) and Uriel who made a few very nice colour images of the LT-2A transport. You can see Uriel's work in the comments section of the LT-2A in my personal gallery.

Cheers and thanks for all the feedback.

[docprice]

awsome concepte.

painted on the tail

"We Bring the Pain"

[Parker Midwinter]

Fafnir_6, you're right... setting the wingroot at the top of the fuselage would likely help, broad wings would also help with stability... minor nit-picks asside, this is a bad-ass design through-and-through.

can't wait to see the next one!

[Fafnir_6]

Thanks, Parker Midwinter, I appreciate a little constructive peer-reviewing. This is especially true since I am branching out from pure deep-space designs to trans-atmospheric ones. I need to build up my knowledge of aviation design tips to make functional aircraft. Having knowledgeable people such as yourself give input is a huge help.

I'll be posting new material soon.


Fafnir_6

[psCargile]

Some pointers concerning aerodynamics. An aircraft designed to be stable, is not very maneuverable, as a maneuver is a departure from straight and level flight. Hence, fighter aircraft are designed with some element of instability. Note the difference between transport and fighter aircraft of any era.

Each flight regime (subsonic, transonic, supersonic, and hypersonic) has an optimum aerodynamic design that doesn't do well in other regimes. Aircraft designed for efficiency at supersonic speeds, are less efficient at lower speeds. The problem everyone should note is that all aircraft must fly at subsonic speeds at least twice during a flight. A design always has a compromise. In the hypersonic range, the requirements of thermo-aerodynamics dictates the aircraft look. Unfortunately, the subsonic A-10 planform doesn't fit that category. And to get into orbit, you need to go hypersonic. The artwork is terrific. However if you are going for extreme realism, it doesn't hit the mark. For pseudo-realism, it kicks ass.

If you are like 99.9 percent of all sci-fi fans, your ideas on space flight may be flawed as most science fiction erroneously treats space flight like air flight.
Orbital mechanics can be confusing at first, but from what I've been able to understand, there is no travel in straight lines (barring the use of gravity shielding devices). Spacecraft travel in circles, ellipses, hyperbolas, and parabolas. This is the nature of gravity and orbits. Increasing velocity on orbit has the effect of increasing the size of your orbit, decreasing velocity the opposite effect. A spacecraft has to retain a certain speed to stay in orbit. The ISS, for instance, speeds around the Earth every 90 minutes at 17,500 mph. Any slower and its doing a Skylab or Mir reenactment.

Useful links:
Aerospaceweb.org | Reference for Aviation, Space, Design, and Engineering (http://www.aerospaceweb.org/) A great place to learn aerodynamics that's not too technical.
Atomic Rocket main page (http://www.projectrho.com/rocket/index.html) This site is about Hard Science Fiction. If you learned about space travel from sci-fi, this site will re-educate you. It destroys a lot of preconceived notions. You will cry on the subject of war craft.
Basic of Space Flight: Orbital Mechanics (http://www.braeunig.us/space/orbmech.htm) Orbital mechanics explained. It is a bit technical.

Again, great artwork, great detail. I think that if you want to do more realistic designs, some research will go a long way. It's not my goal to find fault, but to pass on the things I've learned in the pursuit of realism and hard science fiction.

[Kadaeux]

Great work matey, but I presume that this is a ground attack or "space" bomber? (I assume it is due to being based off of the A-10, a beautiful plane.)

As for the question of atmospheric egress it's solved with "relative" ease. A "lifter" vehicle to get it back up. Something large enough, well protected with big enough engines to lift from the atmosphere with say a whole squadron in the hold.

[chrono]

Good olde science realists always stopping at the edge of knowledge because the abyss of imagination is to scary to jump into.

They do however bring up a valid point, and that is when you are pushing beyond the established knowledge you must decide either to completely adhere to the established ultimately limiting yourself to little more than a photocopier or fixedly leave it behind for imagination. The 3rd option is the most painful one. That is one of compromise, which usually makes no one happy.

[psCargile]

There is striving for realism, and striving for coolness. When you've accomplished cool realism, you've achieved something. I think Fafnir has the potential to do that.

[Adamastor]

actually there is no need for hypersonic flight to get into orbit. escape velocity it the theoretical initial velocity you would need to get into orbit without any further impulsing force. in practice no vehicle that has left for orbit or beyond has ever reached the escape velocity. as long as you can keep climbing (aerodynamic lift only gets you so far but anything that can carry enough fuel to overcome its mass will do) you can take your sweet time to get into orbit, no need to break the sound barrier.
also note that although there is a minimum speed to prevent degradation in orbit that speed does not exceed the speed of sound as the speed of sound increases with decreasing density and reaches "infinite" in a "vacuum".

i didnt see any new images but the old ones still rock something wicked. pretty much all your design are damn sweet and i cant wait to get my eyes on another ;)

[psCargile]

Hypersonic speed is Mach 5 and over. The Space Shuttle reaches Mach 25 to insert into low Earth orbit. Escape velocity (or more correctly "speed") is the speed required to escape the gravitational influence of the nearest body. Things in orbit haven't escaped. Speed is energy. The way you get into orbit or escape, is by matching in kinetic energy the potential gravitational energy of the planet (or moon, or sun, or whatever). That kinetic energy is expressed as speed. It can't be expressed as anything else. For Earth, the escape velocity is an astounding 11.2 kilometers per second, or 25054 miles per hour, or Mach 33.

Follow me on this: Aircraft need air to generate lift. When there is an abundance of air, or high air pressure, wings can generate lift at slow speeds--like a Cesna. When air pressure is low, such as at high altitudes, aircraft have to travel faster to maintain lift--such as the X-15. Air traveling over the wings at high speed has the effect of increasing the air pressure over the wing. Even if you made a Cesna air tight and had an really efficient engine that had great gas mileage, you can't fly it into orbit. A Cesna 172 has a service ceiling of 14,000 ft. That is as high as it will go. It's engine is not capable of providing enough thrust to generate enough relative wind for the wings to generate lift. And that is not 14,000 ft above sea level. That is 14,000 ft based on an idealized air pressure at sea level, or based on density altitude, which depending on the air pressure, or temperature, could be lower or higher than the actual above ground or seal level altitude.

While there have been high altitude research balloons, reaching orbit by balloon isn't possible, otherwise we would have been using this cheap mode of transportation decades ago. I believe that air pressure may have something to do with it.

The speed of sound is not infinite in space. It is zero. Sound travels faster through dense materials. It travels four times faster in steel than in water. Currently I am a Level 2 ultrasonic inspector (a.k.a as NDT or NDI (nondestructive testing/inspecting)) working at Vought Aircraft Industries. I know sound. We have to inspect everything either submerged in water tanks, or having the sound transmitted through a water stream because sound travels too slow in the air to retain the signal strength.

The flip side to this is that you don't have to break the sound barrier to return to the Earth. Burt Rutan's brilliant design of feathering (or changing the pitch) of the empennage (or tail) of SpaceShip One proved this.

[Kadaeux]

*Snip Most*

Hmm, I just considered the possibility of aeromorphing wings. Basically something like the fictional "programmable silicon" or "Mal-metal" where the metal/silicon/turd changes shape and density according to electrical input of its "circuits."

ETC: in atmosphere as it got closer to the ground the K-5A would develop the more common A-10 wingform but as it increased in altitude its planeform would alter to more easily accomodate a shape more fitting for Escaping the atmosphere.

[psCargile]

That's an excellent solution.

[chrono]

When you've accomplished cool realism, you've achieved something.

Not really for all you've achieved is a compromise between the 2 ideas. Coolness is the publics decision.

Every time I see people shout "SCIENCE!" it screws the thread into technical dogma and ends up railroading the artist either into stopping their design or doing it the way the "SCIENCE!" shouters say.

VERY few people who shout "SCIENCE!" add to the actual visible design and tend to masturbate over the underlying & normally invisible issues/principles that in the end have little meaning (especially since it's doesn't add to the visiual of the design) other than moving the design into someone else's idea's of what the design should look like.

Just remember that you aren't arguing with another "techie" at work (where being 'wrong' means losing face or money) or need to prove that you are correct through walls of text or equations when a simple link or 3 will do what is needed (showing an alternate set of ideas).

Balance is the key, but the visuals are the kings.

[Kadaeux]

That's an excellent solution.

Thanks :D

[psCargile]

I consider the F-4 Phantom II to be one of the coolest looking jets. It doesn't look that that way because a bunch of engineers thought it would look really mean and kick-ass. The wing tips are canted up and the horizontal stabilators are angled down as solutions to aerodynamic problems encountered in wind tunnel testing. To me, that's cool realism.

I didn't ask Fafnir to make this concept more realistic. I think its great the way it is. I just noted that he has in incredible attention to detail like I do, and if he considered a more realist approach on some other project, I offered some friendly advise and some helpful websites.

Oh yeah. How about this for cool realism?Boeing: Boeing Unveils Bird of Prey Stealth Technology Demonstrator (http://www.boeing.com/news/releases/2002/q4/nr_021018m.html). I would have expected something like this to have been the imaginative invention of a 3d modeler, but no, aerospace geeks beat us to it.

[Kadaeux]

Oh yeah. How about this for cool realism?Boeing: Boeing Unveils Bird of Prey Stealth Technology Demonstrator (http://www.boeing.com/news/releases/2002/q4/nr_021018m.html). I would have expected something like this to have been the imaginative invention of a 3d modeler, but no, aerospace geeks beat us to it.

Personally it looks like a paper aeroplane :p

(Well actually it looks like a B-2 with its wings clipped :D

[B.J.]

^ I got to be there in person for the unveiling! :D

[Choo1701]

^ I got to be there in person for the unveiling! :D

two bucks bet that you looked at it and thought "That doesn't look very Klingon-ish" :devil: :p

BTW: kudos to Fafnir. Love the flow on this design. :thumb:

[Fafnir_6]

Wow you guys have been busy while I was away! In any case, I'll take the links and discussion to heart as I believe in growing my skills as a ship designer. Thanks to everyone.

@Kadeaux: When you talk about morphing plane form, are you referring to variable geometry and wing chord/camber?

@psCargile: Thanks very much for all the info, it will be a huge help on future projects. About the multiple stages of flight, I have always been fascinated by the SAAB J35 Draken which has a very highly swept supersonic wing form as well as less highly swept, lower speed wingtips. Perhaps this could be a solution?? I think the space shuttle uses this principle as well. Also, could you elaborate on the baloon thing?? BTW, I work as an electronics tech for Acuren Group which is an NDT company. One of those strange convergences, I guess :).

This has been a very fruitful thread for me, helping my deep space designs as well as the atmospheric ones. Thanks everyone for the constructive (and informative) discussion.

[Adamastor]

with fafnirs blessing of the sciencie side of the discussion, here goes my rebuttle :D :


Escape velocity (or more correctly "speed") is the speed required to escape the gravitational influence of the nearest body.
escape velocity, although being incorrect, is still the used term. it is the speed you need to have on the planet's surface if you were to have no further impulse. if you have a engine that can give vertical thrust of any sort you dont need to reach the escape velocity to escape


Speed is energy.
speed is not energy. speed gives a form of energy but they are two different measurements.


The way you get into orbit or escape, is by matching in kinetic energy the potential gravitational energy of the planet (or moon, or sun, or whatever).
the way you go up is by having enough vertical force at all times to give your mass a greater acceleration than the local pull of gravity. on the earth's surface a 1kg item would need more than 10N of force to start going up. if you were to maintain that force you would (eventually) reach orbit and beyond.



That kinetic energy is expressed as speed. It can't be expressed as anything else.
except that it cant be expressed as speed at all but rather as energy. it is the result of speed and mass though.


For Earth, the escape velocity is an astounding 11.2 kilometers per second, or 25054 miles per hour, or Mach 33. on the surface. it is impossible (at least for now) to reach such a speed on the surface, it is much simpler to keep having thrust and keep accelerating up. as you rise you dont need to reach such a speed to escape

as for planes and balloons. planes generate lift by the mechanism you said and loose capability of generating lift as the atmosphere thins. you loose the ability to climb and could never generate lift to get into a vacuum. also the air breathing engines would die out..
balloons on the other hand simply float. low density floats on high density like a boat on water (average the density out for the entire vessel, not just the steel and such). as the balloon rises the air gets less and less dense until the air density matches the balloon's density and no further rising is possible.
it might be an interesting ideia for the scifi-head to have a high altitude, balloon suported, launch platform. it should cut launch speed and fuel down nicely in any backstory. (not sure about any real usefulness though)


The speed of sound is not infinite in space. It is zero. Sound travels faster through dense materials. It travels four times faster in steel than in water. when you compare water and steel, density is not the only significant change. i suggest you compare hot and cold water for example. hot water (less dense) will have a higher speed of sound than cold water. same applies for air. only reason there is no sound in space is that there is not enough matter to propagate the wave which is why i used the "". i can look up the equations if you want.



after all that, in case anyone is still reading, i am with chrono on this one. shouting science at a design does not help. im all for realism if that is the direction the artist goes in but never forget that sci-fi has that "fi" component. fiction roams free. if "inertial dampeners" and such are allowed then long live sweet designs that might never fly!:thumb:

[Fafnir_6]

Thanks Adamastor. I was thinking about this very thing last night. I saw a CF-188 demonstration at a airshow a while back where the plane just pointed its nose skyward and flew straight up. The required force to lift the plane was derived entirely from the thrust of its engines (greater than 1:1 thrust to weight ratio)and not from the lifting force of the wings (although they do control the straight flight of the plane).

Given that the K-5A has engines which do not breath air and that those engines can provide enough power to push it to enormous speeds (which would burn the K-5A to a cinder at high atmospheric concentrations) why can't the K-5A just rocket upwards indefinitely. Once the air density gets too low for the low altitude flying surfaces to work, the control thrusters used for deep-space flight could take over to keep the K-5A pointed the right way for planetary egress. The tricky part would be joining up with the orbiting mothership which as pscargile stated, would be zinging along at huge speeds. Like you said, it's all curves in space, the egress flight profile could take the shape of a low-speed vertical/near vertical ascent at near the surface, then as the atmosphere thins alowing more speed for a given amount of friction, the K-5A could begin to spiral away from the planet with the required acceleration to match speed with the orbiting mothership. Certainly this kind of flight path could be governed by the K-5A's navigational software, taking current position/altitude/speed of the K-5A and those of the mothership and compute a straight, then spirally intercept course. Naturally the K-5A would be more vulnerable to attack at this stage of its flight. Anyway, I thought I'd throw this past you guys to see what you think.

Thanks also for answering the balloon question as well. I have a heavy shuttle under development for the Calmenae faction here that uses a balloon for a portion of its flight path. I don't think it is any less practical than it was before this discussion, although the added knowledge helps enrich the accuracy of the planned re-entry scheme. I'll post the S-3(I) here when it is complete.

Chrono stated earlier that the compromise between existing knowledge and fantasy is the hardest compromise to make so that a design is realistic-seaming. I agree, but I also thrive on making this compromise. The designers of the F-4 started with what need to be done and the result was cool-looking by happenstance. I do it backwards, trying to start with something cool-looking and then messing with it until it might just work. Certainly the discussion here goes A LONG way towards making this process easier for me. Thank you everyone.

Fafnir_6

[Kadaeux]

@Kadeaux: When you talk about morphing plane form, are you referring to variable geometry and wing chord/camber?

In a sense both and neither. While it would fit the description of variable geometry in truth it is literally as I described. The "wing" morphs according to required shape. It would seemingly "flow" more like a Liquid than a wing moving in or out as required. You can find the concept in several science fictions in fact. (The specific one I mentioned is in Peter F Hamiltons Commonwealth Saga where rich people can go to a specific planet to fly these gliders and reach low sub-orbital flight vectors with the aid of tornadoes alone. *No engines.*)

The Wings could go from wide and thick for more lift at low altitude to an almost non-existant dart shape when "diving" through the tornado.

Picture the T-1000 from Terminator how he can re-form his limbs. I'm talking about wings that do the same thing.

[Parker Midwinter]

i think the morphing plane form would be neat... but that idea's been put into practical use since the Me-109... in the form of leading-edge slats, and flaps... look at the A-10's flaps... they slide back, completely out of the wing, giving it a longer inner-wing area before they start to curve down and become more like conventional flaps.

Kadaeux is thinking of something along the lines of the YF-21 from Macross plus, which can expand and contract and warp it's wing, almost like we can with our hands and fingers... not quite the extent of going from something like the F-22 to the U2's type of wing... but a little bit, to improve manoeuvrability and handling at super-low and super-high speeds, and in ultra-thin to ultra dense-atmospheres.

also, on the note of orbital recovery and tremendous speeds... that's what flight-computers, ATC computers on the ground and ship [interlinked and all computing data at the same time, which is what we'd have at this stage] are for. use the the awesome sci-fi ship mumbo-jumbo work for you, in places that it fits with how things are progressing.

[psCargile]

escape velocity, although being incorrect, is still the used term. it is the speed you need to have on the planet's surface if you were to have no further impulse. if you have a engine that can give vertical thrust of any sort you dont need to reach the escape velocity to escape

They why do they bother calling it "escape velocity", O master scientist? If you are not maintaining a speed of 17,500 miles per hour in LEO, you are coming down. Ask the Skylab and the Mir space stations. They weren't reboosted. Gravity got them. And yes, it is true that the pull of gravity weakens. I assume everyone knows that. Which is why I don't mention it. And yes, at 50,000 ft the escape velocity is a lower number. 11.168 km/s to be close, and that not a far cry from the 11.2 km/s from the ground. Even at 100km up at the edge of space, the escape velocity is reduced to 11.09 km/s. Still pretty damn fast. Still higher yet at the ISS's maximum altitude of 460 km, the escape velocity is 10.797 km/s. Not really a significant drop.
Oh, and let me add, that these figures are figured without including air resistance, which really would only be a concern for producing thrust. The required speeds remain the same.

Research: Escape Velocity (http://hyperphysics.phy-astr.gsu.edu/hbase/vesc.html#c2).
B-52/X-15 or WhiteKnight/SpaceShip One are examples of craft being launched to the edge of space and into space from another aircraft. This allows the craft to use less kinetic energy to reach space because it has already obtained potential energy from the aircraft.

7.6 km/s will be enough speed as produced by your thrust to put your craft into Low Earth Orbit. Anything less will not get you into LEO. If you don't have the thrust to produce that speed, you will not have enough kinetic energy to overcome gravity so as to get into an orbit. That is as simple as I can put it and if you don't believe me, you don't believe the scientists that discovered all this and use it. I'm not pulling this out of my ass for a lousy one-upance. I'm trying to educate.

According to this Wiki page: Apollo 10 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Apollo_10), the Apollo 10 set a speed record of 11.08 km/s. Are you starting to get the picture now? Or do you wish to continue to refute science and math?





speed is not energy. speed gives a form of energy but they are two different measurements.



Yes, I believe my exact words were: "That kinetic energy is expressed as speed. It can't be expressed as anything else." I don't consider the members of this forum to be idiots. I figured everyone already knows that the energy is from the thrust.



it might be an interesting ideia for the scifi-head to have a high altitude, balloon suported, launch platform. it should cut launch speed and fuel down nicely in any backstory. (not sure about any real usefulness though)

You are suggesting that a multiton spacecraft be lofted up to high altitude via balloon, or that the balloon is parked by a long tether at high altitude and spacecraft fly up to it, park, and then launch into space?


when you compare water and steel, density is not the only significant change. i suggest you compare hot and cold water for example. hot water (less dense) will have a higher speed of sound than cold water. same applies for air. only reason there is no sound in space is that there is not enough matter to propagate the wave which is why i used the "". i can look up the equations if you want.

Dude, working with sound is my freaking job. I know my freaking job. I had to take freaking test developed by people far smarter than me on the subject. (Got high scores too, by the way.) You contradict yourself. You are correct (in this post) that there is no sound in space because vibrations can not be transmitted by particles that don't touch each other. Hence space has a low density, if you want to put it that way--the particles are far apart. When water gets hot, like all things that get hot, the particles have more energy, are bouncing off each other like a mosh pit, and thus farther apart, making hot water less dense than cold water. The follow through is that sound travels faster in cold water. At least it does in my immersion tank at work. "Are the laws of physics different in your kitchen?"
Hot summer air is a "low pressure cell". Cold winter air is a "High Pressure cell". Low pressure, high density. High pressure, low density. I know we want to automatically assume "Hot" with "High" because of the "H's" and all, but it's not correct.


after all that, in case anyone is still reading, i am with chrono on this one. shouting science at a design does not help.

Does not help who? Are you afraid that knowledge will ruin your appreciation of sci-fi? I hate to be blunt, but any skilled person can draw or model something cool. It's just throwing together cool shapes to make something look really sick. And yes, it takes imagination to put those forms together in a kick-ass way. When you let the boundaries of science limit you, then you are challenged to solve self-imposed problems. It makes coming up with some sick kick-ass design a helluva lot harder. That's what I mean about achieving something.

As a side note on this, I used to be the kind of poster that always had to be right. Today, if I don't know something, I don't speak about it. I know my ignorance. By which I mean I know the boundaries of my knowledge. If I don't know something, I will damn sure learn it. I could care less about the one-up game. I prefer to say something correctly, and say it once. I don't believe in highjacking a thread for several post in an argument. Often it is very likely that we are discussing the same thing but from different levels of comprehension. I assume that everyone here is smart, that we all have some fundamental level of scientific understanding. Assuming that (and no wise cracks about assumptions), when I talk science, I will leave out a lot of minor details that I believe most everyone already knows. I don't want to write a damn textbook just to explain something. If I get some rebuttal that I think is idiotic, I will often just let it go.

[Fafnir_6]

I think you guys are both right. Correct me if I am wrong, but Adamastor is referring to using thrust as a means of counteracting the force of gravity (as demonstrated by the straight up flight of the CF-188 (Canadian F/A-18) and psCargile is referring to high speeds parallel to the earth's surface required to get/keep an object in a stable orbit (as demonstrated by Mir being too slow and falling back to earth). I would assume that Adamastor's system would be needed to get a ship to a suitable high altitude at which point its flight path would have to transition to a high speed orbit using psCargile's system. A curved trajectory??

I intended the K-5A to fly around as an airplane in the atmosphere but for it to rely on its engines/control thrusters/guidance computers for planetary ingress/egress at speeds which would not result in the ship wrecking itself. The K-5A's wing structure is inherently subsonic with a maximum safe speed of say Mach 0.9 or so. So then, fly the ship straight up at mach 0.9 and then once we are free of enough air density for the friction to be low enough for the K-5A not to burn up when we accelerate to 17500mph then we convert to a orbital flight path. Whether or not this is doable at the arbitrary LEO rather than a medium or high earth orbit is beyond my powers of estimation. I assume this scheme could work for the re-entry side of things as well, using very fast control computers and the braking engines. This would be different from the modern as of 1979 space shuttle in that the shuttle doesn't have the braking engine power/control required to perform this maneuver and instead uses the friction of the atmosphere at high speeds as its brake, necessitating the need for those *^$&ing ceramic tiles.

I guess this would boil down to a case of which science fictiony technolgy do you want? super-fast control computers/uber-powerful engines or a heat shield that can still function effectively if it gets hit by foam. There's always anti-gravity too. Yay star trek. The ceramic heat shield might be undesireable for an attack ship that may have to fly through a planetary fighter defense network to achieve its mission. The K-5A is primarily a ground attack / troop support ship and most of its fighting will be at A-10 like altitudes. I'll design some hypersonic escort fighters to help them reach their destinations.

Again, correct me if wrong,

Fafnir_6

[psCargile]

I'm trying to tell you both that you can't fly .09 Mach into space. Otherwise we would have been doing that since the birth of the jet age. Right? Doesn't that make sense? We would have bypassed rockets altogether with space planes. Hypersonics is being studied again so that eventually in the later half of this century, if not sooner, we can have a space plane.

Heat problems? Well, it is sci-fi, so consider a real good composite material, or some kind of projected shield. If your plane needs to go fast, then it goes fast. It has good engines. The Space Shuttle isn't the perfect hypersonic vehicle. It's not designed to travel at hypersonic speeds for very long. It takes about 12 to 15 minutes to get into orbit. It's ramming itself through the atmosphere. The K-5A can ram itself through the atmosphere on a power climb too.

One of the reasons that I decided to post all this stuff is because your design mirrors a project that I've been working on with Frank Bonura for his Star Wars rpg. That project is deceased author Brain Daley's Headhunter from "Han Solo at Star's End". We've been working on this bird on and off for over a couple of years, most of that research. The Headhunter does what your fighter does, so this is familiar territory.

[Fafnir_6]

Ahh I see. Well it sounds like a good idea to pool research data.

What I don't understand is that if you have an engine that can provide a constant, adequate supply of thrust in a dense atmosphere and also in a vacuum to counteract the force of gravity (which I believe is the only force that is trying to keep you on the planet's surface). Why can't you just power upwards indefinitely. Obviously you can't do something like that with an altitude-limited jet engine. I thought that's what rockets were for. I also don't understand why you have to accelerate to such rediculous speeds while still having the resistance of air to cause all the problems with heat and such. I would say just use a controlled blast up to some altitude above earth where air resistance is negliable and then accelerate up to orbital speeds. this would negate the need to morph your hull to a hypersonic form.

Sorry I am being so difficult to educate :). Obviously if there is some requirement to get to orbital speeds while still in the atmosphere, you will need a hypersonic ship hull. Please explain why the above is not possible and I promise I will stop pestering you with this.

Cheers and apologies,

Fafnir_6

Edit: If you go here: Escape velocity - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Escape_velocity) in the "misconceptions" section it seems to support what Adamastor and I have been saying about low-speed planetary egress. I checked out the sites you linked and none of them seem to contradict this either (the page on hypersonic ship design was very interesting BTW).

[docprice]

since when did threads on SFM become a place for flame wars. wow its a 2D drawing with the strong potential to become a 3D model. last time I checked mechanics of exiting the gravatational pull of earth were not essential in rendering 3D models.

This thread seems to have derailed from its original path.

[Adamastor]

i apologise to cargile if he is offended by anything i said. i was hoping for some back and forth on the subject but it seems to have gotten out of hand. you sound (well, i guess 'read' would be more appropriate) like the king of person that will not be persuaded, so even though i stand by my statements i am willing to drop the whole matter.
anybody willing to do a little research can find definitions and formulae that will probably be true and might support either argument just as easily.
also sorry to fafnir for sidetracking his thread. should anybody wish to continue the physics discussion feel free to pm me

[Fafnir_6]

No need to apologize to me, the discussion has been...educational. The links that psCargile sent have answered some other, unrelated questions I had as well, so overall this has been a very productive thread for me. Also, the K-5A is old news to me as I will soon begin work on the K-5B using all the information I have gathered since its release to improve/correct some aspects of it. The discussion has also resulted in some changes to the transatmospheric B-2C bomber and S-2(III) shuttle projects which I had put on hold until the discussion here had run its course.

Cheers,

Fafnir_6

[Parker Midwinter]

What I don't understand is that if you have an engine that can provide a constant, adequate supply of thrust in a dense atmosphere and also in a vacuum to counteract the force of gravity (which I believe is the only force that is trying to keep you on the planet's surface). Why can't you just power upwards indefinitely. Obviously you can't do something like that with an altitude-limited jet engine. I thought that's what rockets were for. I also don't understand why you have to accelerate to such ridiculous speeds while still having the resistance of air to cause all the problems with heat and such. I would say just use a controlled blast up to some altitude above earth where air resistance is negligible and then accelerate up to orbital speeds. this would negate the need to morph your hull to a hypersonic form.

Just like the wiki article says: if you get up high enough, your local escape velocity will eventually decrease to 0km/s... and the only thing stopping you from attaining that altitude is the Earth's gravitational pull. Going straight-up, provided you have the thrust, is the best way to go... otherwise you'd be around the world twice before you got up to speed to get out.


Heat problems? Well, it is sci-fi, so consider a real good composite material, or some kind of projected shield. If your plane needs to go fast, then it goes fast. It has good engines. The Space Shuttle isn't the perfect hypersonic vehicle. It's not designed to travel at hypersonic speeds for very long. It takes about 12 to 15 minutes to get into orbit. It's ramming itself through the atmosphere. The K-5A can ram itself through the atmosphere on a power climb too.