i.e.see my reply in blue.
I think our pseudo aerodynamicist-wanna-be is not very familiar with google:
Very brief introduction about this rather simple concept of lifting-body can be found here:
http://en.wikipedia.org/wiki/Lifting_body
I am aware there is a thing called “google”, I am also aware that any hobo can go on to wiki and write this section.
And of cause, these “space” ships you claimed are all tested under atomosphere with low mach, appenerantly, using the lift creates by their lifting-body, it seems that the their lifting-body still work within atomsphere.
please go back and read my comments again,
I am not claiming lift generate from the body doesn’t exist. The way you look at the problem, i.e. touting around “body-lift” like it is something one can talk about seperately, is the what I have trouble with. in real world where people do this for a living people don’t talk about things in the perspective you provided.I think thats the problem with our amaterish wanna-bes, it seems that they have difficulties in understanding any simple concepts.
Yes, I think our difficulties is with amaterish wanna-bes like you, with all due respect.As for lifting-tonque? well thats very simple:
Since the lifting-pressure exerted at the body of the fighter is actually not matched magically instead it will most likely created a tonque, instead of acting like just a force straight pointing upwards at the weight center of the fighter.
Thus, the lifting-tonque created by the lifting body need to be matched by the tonque created by the controllable surfaces like the canards(for a canard-fighter) through means of flight control system, to prevent the fighter from (if) un-wanted body-rotation, get it? my rather not-very-bright boy?
I see, well.
fyi, The technical term for what you thinking is pitching moment. and btw, how many real project have you worked in the industry?
btw, just a friendly advice:
I think you are bit out of the league to argue with me on these technicals stuff.
if you are able to read/write chinese, then do go on to fyjs.cn and just casually ask for my name, I am sure they can give you some point of reference.
i.e.see my reply in blue
The European plane is not going to sell more than a plane meant for the USAF, USN and USMC.
mirage 2000 did well in its day. no reason not to reproduce that result.
Whats wrong with their current procurement for this humanitarian intervention role?
the places they will “humanitarian intervene” would not have highly sofisticated integrated air defence require geewiz of F-35. and if it did, Europe will prob not march into war with US.They are allies of the USA, i think to work with the US military would be a high priority for several European military forces.
sure, but they don’t need a F-35 to drop bombs.
Europe is a high technology economy, and they will want to keep the lead in technology with their new plane, economic recovery permitting.
yes. and have a high tech economy does not mean they buy some plane from someoneelse, it means to make one.
From this signature management point of view the F-35 was to serve with a military with no global equivalent, in an era when the very competitive IADS threat of the Soviet Union (which was improving every decade) was no more, the F-22 program was supposed to fight with that.
exactly my point
At a point where both the planes give very small RCS and carry high performance air to air missiles what else is left but the sensors?
numbers. 😮
i.e.Congratulations to China!
It really was 11/1/2011, I didn’t believe it, I missed the moment 😮I am not surprised that the Chinese had such an achievement, I remember the time when I lived in China, people told me Chinese are head-bowed, hardworking, like a willing and quiet ox, I thought that was great. I noticed here are some Chinese, congratulations to you guys.
Konnichiwa Shinnosuke San.
Amaze the World with a Single Feat.
Will japan seriously pursue Shinshin now into a real fighter?
i.e.It would indeed, but to make any sense of the results I would also have to look the record that Jane’s US, French, or Israeli sources have of predicting Chinese ….
Contrary to popular belief, defence companies rarely ‘knock’ their rivals. It is not a productive tactic, and if exposed, could reflect badly on the company that did it.
I am in a good mood today,
just to throw a monkey wrench into the discussion.
there is this Russian working for Yang Wei closely at chengdu. He is Yang’s protege. 😮
i.e.what the heck.
let’s start a rumor.
IOC 2015. 😎
i.e.A very interesting statement, considering the cost of current platforms in Europe.
The F-35 has quite a lead on sensors over the current fighters in europe (or so it is said in the reports), which is a cause of its high price, i suppose anyone in Europe would go for a 5th gen platform right now, they would in all probability look for a capability beyond the F-35, which would make it a more expensive program.
cost comes down with procurement size.
a stealthrized platform does not need world beater sensors to be competitive. in another word. it is getting to the point where it is cheaper to stealth than to have geewiz sensors.
from my understanding the geewiz associated with F35’s sensor came from dealing with highly integrated airdefence system.
vast majority targets and enviornment where euro forces expect to operate does not need geewiz. they will not invade russia and they will not invade china. the most hostile enviornment they will be in is prob something like a yugoslavia, i.e. sone sort of “humanitarian Intervention” i.e. 3rd world door kick downs. thus the emphasis on air-2-air and airdefence should decrease the need for geewiz and cost.
(now unless they want to be in the business of bomb delivery guys for USAF forever. ignore what I said.)
the fighter needs to be competitive. and that’s enough for deter wars. which
is the first point of having a military.
i.e.try google WS-10G FADEC, althrough we are all waiting for an official announcement:cool:
my view on fadec.
“fadec”ing a unfadeced engine is relatively un-interesting. improvements around edges etc. sure. it is nice. but it does not change the primary cardinal parameter. your t/w is stil such and so is your sfc rating etc.
the real “ooommmphuuu” is for those engines that designed ground up as fadec engines.
in another word: engines become control configured. just as fighters has become control configured.
so what’s the “ooommmphuuu”? well, if you really utilize what you have, you can really decouple alot of dynamics and squeeze the gain into weight saving/performance gains.
new generation is such. I am not sure but it would be really interesting if WS-15 is “control configured”.
i.e.just man up and jointly develope a mid-sized 5/6th gen oriented towards air-to-air, air-defence.
there may be more market for these things than one think.
especially if it comes under $$ vs F35.
i.e.I’d agree with all of that bar one little bit.
Having effective fuselage lift at angles of attack below 25 deg (or so) can make or break a fighter in terms of sustained turn performance.
Post stall maneuvering is all nice and fine, and can be useful in some situations; however Boyd’s energy maneuverability theory still rules the dogfight, and from that going to AoAs above 25deg or so is a direct route to death.
oh I agree with the part you said about the pressure distribution on the body.
L/D is always the name of the game.
but one do not just flatten the fuselage and think they will get all this nice extra lift for free. there is pitching moment and center of lift issues ( never forget about trim) forebody breakaway and vortices etc etc. it’s not additive.
not as simple as some here would like to believe.
…
last bit about post stall.
the name of the game in post stall is all about how much nose down pitching moment you can generate to get back into useful part of that lift curve slop. it is not about lift anymore. who ever flys around in post stall all day would die in an real aircombat very soon.
here is where big canards shines.
i.e.On your first sentence you are indeed correct, readings are normally taken on the wing-body basis.
But it is not a moot point. Having a fuselage that is effective at creating lift is very useful at increasing L/D in severe turns. Of course, you are well aware that lift created along and close to the aircraft centreline is the most efficient in terms of induced drag.
As for which approach is most effective (F-22, PAK-FA or J-20)… you’d probably need a windtunnel to find out.
your last part is my point.
since we do not have a windtunnel and do not pretend our collective hot breath here can create enough positive pressure to generate meaningful L/D curves. then,
it is a moot point.
like you said one (meaning people who do this for a living) do no stick a body minus rest of the plane in wind tunnel and say ah ha it is a “lifting body.”
at high aoas where it is most counted on to give benefit fore-bodies and wing configuration (and for a canard configuration your also need to take in account of that canard’s location deflection size etc.) is critically import to provide those nice vortices on the real body.
even your VT and fins matters at how much lift and drag you generate at these angles. as their angles and size and location may severely affect pressure distribution.
so what’s the point of talking about it seperately? I always find it is odd.
i.e.see my reply in blue:
Look at its side-view, the upper half of F-22 is obivous flatter than its lower half, which creats a air-pressure forces pointing upwards, thus the lifting tonque.
if you look at a positive cambered wing from its cross-section, what do you see?
flat on bottom and curved on top?,
now do tell me which direction is the lift vector, relative to the camber?Of cause high-lifting is not necessarily means better air-combat performance, it is the lifting tonque and their controlablity at high attack angle that matters, otherwise, the lifting tonque may only useful when it comes to ferry range of the fighter.
I assume you mean lifting torque.
tell me what is a lifting torque? exactly?
i.e.Before I say anything let me caveat it by saying that I am not an expert of any kind.
Just as an untrained observer, I think amongst the three 5th Gen planes now flying around J-20 holds its own in terms of its design (Not sure how good that will be for the job). I am sure rather than re-inventing the wheel the Chinese might have borrowed some features from F-22.
It is remarkable for China to come up with J-20 so soon, given the relatively short history of their aviation industry. They have taken a gamble on its design rather than use a derivative of something flying around.
T-50 on the other hand does look a bit Flankerish, if one had to come up with a stealth version of SU-30, it won’t be far off the current T-50. Maybe Russians are not reinventing the wheel in some areas?
I think this is a fair statement.
aerodynamic wise the J-20 configuration also borrow extensively from the configuration experience they had with J-10. the aerodynamicist has enough confidence in the pd stage that his configuration would deliver the required coefficients to satisfy all the requirement. his tool and his process works. and they are close (depends on J-10 program’s correction on these tools and process) to what the final result will be.
Flanker is a good platform to work on and I am sure the aerodynamiicst at sukhoi has plenty of experiences with it and are confident and aware of its strength and limitations. same as in Chengdu.
one should always look at the requirement as well as final product and their processes and tools to be able to pass judgement. and that would only be a judgement from an uninformed outsider with out any real information to go on.
i.e.Hello folks, I would like to question the existance of weapons bays on this aircraft after having read through the many previous posts. To my eyes they appear to be place holders for where the bays will be on the next prototypes/tech demonstrators.
I do not believe they are functional on this aircraft which may be controversial but it is my opinion based on the fact the tolerances look way to tight from an engineering standpoint for the bays to be able open and close.
the bay could exist:
may be just not the production doors.
they would have a nightmare if they have to redesign the cavities and the structures around them.
i.e.Is this J-20 fitted with the holy S-duct? Apparently without an S-duct one cannot be stealthy 😉
the beauty of a good integrated tool is that with DSI and with a carefully designed scoop, you can not only optimize pressure recovery but also take in account of reflectivity.
i.e.Of cause there are more than just one way to create a lifting-body.
The russian’s approach (PAF-FA/Su-27) is just making some part of the body blended with the main wings to creates lift instead of using the entire body as a lifting part.
What I am trying to say is that the its quite hard to create a lifting-body canards due to the controlibility/stability difficulties (the tonque created at canards and these at the body), as for convential layout fighter, lifting-body is nothing special, for instance, F-22 is also quite a lifting-body design.
to trow around the term “Lift-body” around like it is some fashionable word is a terribly naive way to look at things. and a wrong way to look at the problem from a fighter perspective.
hypersonic vehicles and space re-entry vehicles and research perspective? go ahead. but in fighter and transport world we do not pretend that we can seperate “body-lift” from “wing-lift”.
so this whole point is a moot point.
now if you are willing to go in technical details and speculate on the specific aspects, I am all ears.
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