Shenyang FC-31 / J-31 Fighter Demonstrator

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kurutoga

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Our photographer friend now produces better pictures! But the project still has a long way to go, this is only the second flying prototype. Let's don't get too excited. To some extent maybe they should not go to production without the new 10-tonne engine
 
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kurutoga said:
Our photographer friend now produces better pictures! But the project still has a long way to go, this is only the second flying prototype. Let's don't get too excited. To some extent maybe they should not go to production without the new 10-tonne engine
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and of course you could make the same argument for the J-20,, but I wouldn't....producing new fighter aircraft is a process, it takes lots and lots of time and MONEY! you take it one step at a time, make adjustments as necessary, and in the end hopefully you have an effective fighter aircraft that adds capability and gives the "bad guys" pause for thought???
 
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taxiya

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Naw, Naw! come on now! lets not make 3D printing something its not, and lets NOT throw out traditional castings and forgings,,, the printed 3D part still needs "milling", or machining to finish the part and then a final polish to bring that part to specs.

and to be very honest the 3D printing process is basically computer generated "welding" of molten material together through the "printing" process.. while titanium is indeed difficult to weld, its is a process that has been very well mastered,,,, when you're looking at a Lynskey Litespeed,, you want to see welds that look like a "stack of dimes", a "good" titanium weld is stronger than the parent materials, and once those welds are machined smooth, you do indeed have a large one piece structure!

while 3D printing does offer some significant advantages, possibly even more efficiencies and the economy of scale,,, its still not the "Fairy Godmothers Magic Wand!"
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I don't think I am talking about 3d printing as some super-duper magic, but merely pointing out its advantages over traditional method. So I don't think we disagree with each other, except the highlighted texts.

I do not work in the field of metal handling, so I will not comment on the "welding is stronger than parent material". I will just take that as a fact.

However, when the welded joint being stronger than the adjacent area (parent), wouldn't it transfer the stress from the weld to adjacent area? Therefor, the adjacent area becomes weak point? My understanding of structure strength is that one want to have load to be spread out evenly over the whole structure, and avoid having load concentrated to small area which becomes weak point.

Back in the time when I built model aircraft from wood, I once broke one on a hard landing. I joined the airframe with wood plate. Then there was another hard landing due to my clumsy handling, the aircraft broke at the point next to the reinforced joint. So I gave up repairing it knowing it will just repeat. Wood is different from metal, but the principle of load being transferred should be the same.

So my conclusion is regardless how good the welding can be, I would want to make it in one piece than joining three pieces into one.
 
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taxiya said:
I don't think I am talking about 3d printing as some super-duper magic, but merely pointing out its advantages over traditional method. So I don't think we disagree with each other, except the highlighted texts.

I do not work in the field of metal handling, so I will not comment on the "welding is stronger than parent material". I will just take that as a fact.

However, when the welded joint being stronger than the adjacent area (parent), wouldn't it transfer the stress from the weld to adjacent area? Therefor, the adjacent area becomes weak point? My understanding of structure strength is that one want to have load to be spread out evenly over the whole structure, and avoid having load concentrated to small area which becomes weak point.

Back in the time when I built model aircraft from wood, I once broke one on a hard landing. I joined the airframe with wood plate. Then there was another hard landing due to my clumsy handling, the aircraft broke at the point next to the reinforced joint. So I gave up repairing it knowing it will just repeat. Wood is different from metal, but the principle of load being transferred should be the same.

So my conclusion is regardless how good the welding can be, I would want to make it in one piece than joining three pieces into one.
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Very well stated, and point taken,,,, the molten titanium in 3D printing is a marvel, and in the end will likely give you a finished part that may then be forged in a press, heat treated, or machined, likely requiring less machining to achieve a finished part, castings offer similar benefits in general..

A Forging will almost always render a stronger part per weight, due to the heated metal being "forged" and compressed, and the molecular structure being compressed and having a tigher "grain", also forging decreases the chance for "voids" or irregularities in the finished product....

So yes a 3D printed part, or even a traditional casting will likely weigh less and be less dense than a forging, depending on the individual part, that may be advantageous?? Or NOT??

For anyone to suggest though that the J-20 is a 15 ton aircraft as opposed to the F-22 being a 20 +ton aircraft, and that 3D printing results in a 25% weight reduction in an aircraft designed and manufactured to pull 9 Gs is does indeed place that individual in the "Disney Princess" category!

So Chengdu, Shenyang, Boeing, and Lockmart each build EACH individual part with the most effective method for maximum strength and functionality!

but to expect knowledgeable posters to buy the notion that Chinese manufacturing is "light years" ahead of LockMart, Boeing, or the designers and producers of the Eurofighter and friends is just a fairy tale.. YES, 3D printing is awesome and amazing, it is also expensive when the tooling and software are taken into consideration..

So a 3 to 7% weight reduction is no doubt possible and likely, and yes 3D printed parts offer an amazing opportunity by producing a finished part that may require many many hours less machining and produce an accurate part that requires "MUCH LESS" machining and fitting

an example are turbine blades,, 3D printing is going to revolutionize high performance, high efficiency aircraft engine building, but the resultant engine operating temperatures will go way up as well.....
 
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by78 said:
Could you please not post videos from fanboy youtube channels?
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manqiangrexue said:
Says someone in the retired-biased-dotard-in-denial category. You can't pretend to be a big jolly nice guy asking everyone to be civil and kind to each other while you call people Disney princesses, you know LOL.

No one ever said that 3D printing was the only technology that reduced weight on the J-20. It's a contributor, among many other new technologies and design adaptations to lose weight. I've presented a partial list of known weight-reduction measures (I'm sure the actual list on the designer's desk has more measures in it than a wholly mammoth has hair) to you several times and don't care to do it again since you won't recall it next time either. But you saying that since 3D printing alone probably can't reduce entire aircraft weight by 25%, therefore 25% cannot be achieved at all is like someone saying that since a centipede can't walk with 1 leg, therefore, it cannot walk at all!
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I did NOT call you a "Disney Princess", I did state that mind set is make believe,,, I'm far more aware of the physical properties of the varying production methods than you my friend. When you actually work on and fly something that you work on??

in a new book on the amazing F-22, there is a cut-away drawing showing the actual superstructure under the skin of a 10+ G airframe,,, the J-20 and the FC-31 are NO Doubt very similar in order to carry a similar load, and I would remind you that AF-2 has been to 9.9 Gs in flight test!

so you believe "anything" that makes you happy Sunshine,, really, but you ought to show a little respect to your "elders"..... you'll be here soon, before you know it,, won't be able to pass a bathroom, and you'll have to trade in your cute little "red spandex" uniform for a pair of "Depends", and the only weight you'll be lifting is your "tea cup"!

nice avatar by the way........
 
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latenlazy

Brigadier
Air Force Brat said:
I did NOT call you a "Disney Princess", I did state that mind set is make believe,,, I'm far more aware of the physical properties of the varying production methods than you my friend. When you actually work on and fly something that you work on??
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If you think the mindset reflects being a “Disney Princess”, what does that make those who you believe have that mindset?
 
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