Chinese Engine Development

taxiya

Brigadier
Registered Member
It will reach the same stage achieved by the America 20 TWR engine at the year 2019 by 2030.
Did American reached 20 TWR at 2019, meaning an engine (prototyp at least) double the TWR of F119?

The ppt is apparently taking VAATE as a benchmark. But by reading VAATE's detail, it is more of a budgetary program that will never end (itself a revival of IHPTET from 1988), and does not guarantee a target engine. I would treat the ppt in the same manner. They are more of a wish and vision rather than concrete road-map of actual engine, therefor not saying much.

Here is
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and I quote the part concerning staged goal.
The VAATE program goal reflects these requirements, specifically, that by 2017 the military user will realize a factor of ten (“10X”) improvement in turbine engine-based propulsion system affordable capability. “Affordable capability” is defined as the ratio of propulsion system capability to cost. “Capability” in this context measures technical performance parameters including thrust, weight, and fuel consumption. “Cost” quantifies the total cost of ownership, and includes development, procurement, and life cycle maintenance cost. These improvements are to be realized relative to a baseline representative of year-2000 state-of-the-art systems.
The paper is made in 2006, by 2017 it would be 10 years in progress.
In 10 years, the Capability/Cost ratio will increase 10 fold compared with a year 2000 state-of-the-art engine (F-119 and F-135). I don't see anything today that fulfills that goal.
 

latenlazy

Brigadier
Did American reached 20 TWR at 2019, meaning an engine (prototyp at least) double the TWR of F119?

The ppt is apparently taking VAATE as a benchmark. But by reading VAATE's detail, it is more of a budgetary program that will never end (itself a revival of IHPTET from 1988), and does not guarantee a target engine. I would treat the ppt in the same manner. They are more of a wish and vision rather than concrete road-map of actual engine, therefor not saying much.

Here is
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and I quote the part concerning staged goal.

The paper is made in 2006, by 2017 it would be 10 years in progress.
In 10 years, the Capability/Cost ratio will increase 10 fold compared with a year 2000 state-of-the-art engine (F-119 and F-135). I don't see anything today that fulfills that goal.
Because those goals were set as aspirational targets, not technically based projections. Science and engineering as the great unknown rather than the likely feasible.
 

gelgoog

Brigadier
Registered Member
There are engines with a thrust-to-weight ratio of 1:100 available right now. In fact there have been for decades. The problem is those are LOX/Kerosene staged combustion engines which guzzle fuel. Here.
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gelgoog

Brigadier
Registered Member
Not sure if you’re being cheeky but in case you aren’t we’re talking turbofans here ;)

A bit. To be honest hearing about thrust-to-weight ratio in a turbofan of 1:20 seems kind of mythical or nonsensical. Kinda like Intel's roadmap to having 10 GHz processors by 2010. Some kind of pie in the sky goal. That would likely require using denser fuel and an alternate engine cycle. I doubt you can achieve it with a regular turbofan. Maybe something like the SABRE engine would work. You use some sort of cryogenic fuel like liquid methane to chill incoming air to liquefy it and then you burn that. Outside of rocket engines thrust-to-weight ratios like that are unheard of.

I doubt you can get to a thrust-to-weight ratio of 20 with a turbofan. Simply too many parts. I sincerely even doubt something like that is all that useful either. Human pilots would hit G limits if the acceleration was too high.
 

latenlazy

Brigadier
A bit. To be honest hearing about thrust-to-weight ratio in a turbofan of 1:20 seems kind of mythical or nonsensical. Kinda like Intel's roadmap to having 10 GHz processors by 2010. Some kind of pie in the sky goal. That would likely require using denser fuel and an alternate engine cycle. I doubt you can achieve it with a regular turbofan. Maybe something like the SABRE engine would work. You use some sort of cryogenic fuel like liquid methane to chill incoming air to liquefy it and then you burn that. Outside of rocket engines thrust-to-weight ratios like that are unheard of.

I doubt you can get to a thrust-to-weight ratio of 20 with a turbofan. Simply too many parts. I sincerely even doubt something like that is all that useful either. Human pilots would hit G limits if the acceleration was too high.
Maybe the way they do it is by reducing the mass of the parts...
 

localizer

Colonel
Registered Member
I was reading this:
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Since the first aircraft gas turbines were built in the late 1940s, overall efficiency—fuel flow to propulsive power—has improved from about 10 percent to its current value, approaching 40 percent (see
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). It is likely that the rate of improvement of these engines can continue at about 7 percent per decade for the next several decades given sufficient investment in technology. The potential for overall improvement is best considered in terms of the constituent efficiencies: thermodynamic efficiency of the motor and propulsive efficiency of the propulsor.
As noted above, it is not clear how close to the theoretical limits it may be possible to come with a gas turbine for commercial aircraft given aviation’s important constraints of safety, weight, reliability, and cost. Several authors have considered the question of the practical limits for simple cycle gas turbines given the potential for new materials, engine architectures, and component technologies. Their estimates of the individual limits of thermodynamic and propulsive efficiency differ somewhat (and may divide losses differently between thermodynamic and propulsive efficiency), but they agree that an improvement of 30-35 percent in overall efficiency compared with the best engines today may be achievable. As shown in
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, motor thermodynamic efficiencies of 65-70 percent and propulsive efficiencies of 90-95 percent may be possible.
Gas turbine engines have considerable room for improvement, with overall efficiencies improving by 30 percent or more compared to the best engines in service today. Improvements will come from many relatively small increments rather than a single breakthrough technology.
Some studies suggest that improvements in turbomachinery performance and reduction in cooling losses could improve thermodynamic efficiency by 19 percent and 6 percent, respectively.
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This magnitude of gain is not achieved by simply inserting new technology in existing engines. Rather it requires optimization of the cycle given specific levels of component performance characteristics, temperature capability, and cooling. Practical intercooled or recuperated cycles could increase efficiency by another 4.
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Improved fans and propellers could also increase propulsive efficiency by 10 percent.
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Of course, the practical limits to propulsive efficiency cannot be addressed at the engine level alone without reference to airplane configuration and propulsion integration, as discussed in
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.
To summarize, aircraft gas turbine engines have considerable room for improvement, with a potential to improve overall efficiencies by 30 percent or more over the best engines in service today, with the potential for improvement of propulsive efficiency being about twice that of thermodynamic efficiency. This level of performance will require many technology improvements and come in the form of a number of relatively small increments, a few percent or less, rather than through a single breakthrough technology. The following section discusses many of these technologies.

Maybe one day we will see some engine made of pure diamond (4000C melting temp)
 

by78

General
The ZF850 turbojet from Jiangxi Zhongfa Tianxin Engine Technology Ltd. It will soon be used on the Cloud Shadow UCAV. Two pre-production samples have already been delivered, with four more to be delivered by year end 2020. Serial production will commence in 2021. The company is currently exhibiting the engine at the ongoing Nanchang Aviation Conference/Show.

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