J-20 5th Gen Fighter Thread V

[Blitzo]

Agreed. But there is another reason which is to integrate indigenous trust-vector turbofan engine. It can only be WS10 if not 117s. Since WS10 is now reliable enough, it can be a reasonable test bed for their newly developed trust-vector technology.

No, thrust vectoring is not a very good reason because we don't know if the Air Force values TVC or is even considering TVC for the J-20 to a degree that it is willing to expend money to fit an interim engine with it. (In fact it is very likely that TVC may not be on the cards for J-20 even for WS-15)

Furthermore, China can likely purchase TVC variants of Al-31 as well if they wanted engines with TVC that much.

 

[GreenestGDP]

IMHO, Reliability is no longer the issue on is not the problem with WS-10A.

The issues on using WS-10A could be the trade off on:

1) Minimum Stalled speed.
2) ability to Rev Up / Spool Up the engine quickly.
3) shifting the Center of Gravity ( Neutral Point ) of J-20 causing too much redesign, which in turn causing introduction time delay.

4) PLAAF need to develop the (Integration with all friendly assets) Combat Dogfighting Manual for J-20 urgently, they can not wait until WS-15 is mature --- or waiting for the redesign process on WS-10A.


BTW, does anybody know if J-20 required the engine Gearbox to be located at the top or at the bottom ?? My personal guess is J-20 required the engine Gearbox at the top.

 

[pflanker]

There are still several years ahead before WS15 comes out. If they keep improving WS10 variant's performance (which is almost certain), I see no reason not to integrate it to J20. .

It is nearly inconceivable that WS10 can make such a leap in performance even in your wildest dream. There are other factors, such as generation gap, that works against the WS10. Firstly, J-20 needs an engine with high thrust to weight ratio to compete with F-22/F-35. WS-10 will have to lose a lot of weight - even Oprah can't help much here. Secondly, WS15 is the designed with the next generation material to achieve higher core temperature. The new tech is bound to be very expensive.

For the same reason of cost and effort, engine makers will probably not attempt to adopt new tech on old engines.

 

[latenlazy]

It is nearly inconceivable that WS10 can make such a leap in performance even in your wildest dream. There are other factors, such as generation gap, that works against the WS10. Firstly, J-20 needs an engine with high thrust to weight ratio to compete with F-22/F-35. WS-10 will have to lose a lot of weight - even Oprah can't help much here. Secondly, WS15 is the designed with the next generation material to achieve higher core temperature. The new tech is bound to be very expensive.

For the same reason of cost and effort, engine makers will probably not attempt to adopt new tech on old engines.

Old engines get updated with new materials and components to uprate their performance all the time. The fundamental design stays the same, so improvements aren't going to make them competitive with a newer generation of engines, but substantial gains aren't implausible.

 

[plawolf]

It is nearly inconceivable that WS10 can make such a leap in performance even in your wildest dream. There are other factors, such as generation gap, that works against the WS10. Firstly, J-20 needs an engine with high thrust to weight ratio to compete with F-22/F-35. WS-10 will have to lose a lot of weight - even Oprah can't help much here. Secondly, WS15 is the designed with the next generation material to achieve higher core temperature. The new tech is bound to be very expensive.

For the same reason of cost and effort, engine makers will probably not attempt to adopt new tech on old engines.

The developmental and life cycles of pretty much every engine in widespread use runs counter of that.

Every single military jet engine that has been in use for more than a few decades will have undergone many upgrades and versions, the latest of which would be substantially improved in almost every way to the first versions that were rolled out.

The only engines that are not so upgraded and improved over time are the ones that are phased out and abandoned.

Now it is less likely that the WS10 will be used on the J20 more because of timeframe rather than because it cannot be upgraded so.

The WS15 has been in development for a fair few years already, while the J20 already has an interim engine selected, which appears to be a version of the AL31 (which puts the lie to your theory that the WS10 cannot be upgraded so much, since the AL31 already has been), which will suffice until the WS15 is ready.

The WS10 will be improved with time, a later version powerful enough to serve as an interim engine for the J20 is almost certain to emerge. However, it is unlikely to be ready early enough to be used on the J20, and likely will mainly be used to upgrade J10 and J11 fighters that cannot mount the more powerful WS15 once that becomes available.

 

[siegecrossbow]

BTW, does anybody know if J-20 required the engine Gearbox to be located at the top or at the bottom ?? My personal guess is J-20 required the engine Gearbox at the top.

I am guessing the same as the configuration on the J-10.

 

[Deino]

I am guessing the same as the configuration on the J-10.

Me too ... and as such on the bottom ! ... why on top, it would make maintenance much more difficult.

 

[plawolf]

I am guessing the same as the configuration on the J-10.

You can see the access doors lines on the bottom of the primer J20 most clearly, suggesting the gearboxes are on the bottom also.

I'm not sure why the Su27 has its gearbox on the top, sure that makes it easier, physically speaking, to work on the engine while still installed on the plane since you don't have to hold tools and parts above you for prolonged periods, but if you drop anything small while working on the gearbox, well, good luck getting it back out again...

 

[vesicles]

You can see the access doors lines on the bottom of the primer J20 most clearly, suggesting the gearboxes are on the bottom also.

I'm not sure why the Su27 has its gearbox on the top, sure that makes it easier, physically speaking, to work on the engine while still installed on the plane since you don't have to hold tools and parts above you for prolonged periods, but if you drop anything small while working on the gearbox, well, good luck getting it back out again...

Talking about dropping something in the engines. Couple years ago, I tried to change the battery of my wife's VW Beattle. I accidentally dropped a wrench while taking the battery out. If you have seen the under the hood of a modern Bug, you will know that it's extremely crowded. And I spent hours but simply could not find that wrench. I think it is still in there somewhere to this day...

 

[Richard Santos]

Me too ... and as such on the bottom ! ... why on top, it would make maintenance much more difficult.

Whether access from the top or bottom are more difficult depends on the ground clearance on the bottom of the aircraft, As well as other considerations such as does the maintenance point get in the way of other nearby service points and made simultaneous work on multiple service points difficult.

It is physically exhausting to have to stoop or bend down while accessing a maintenance point overhead.