I just hope naval variant based on FC-31 won't use these old Russian engines. Wish them luck!
Chinese Engine Development
- Thread starter jackbh
- Start date
Considering the current FC-31 is already using an improved variant of the WS-13, I would be very surprised if the J-35 does not initially use the same engine as well.
I really hope they couple WS-19 development with J-35. Sure, Navalizing the engine is an extra step that may hamper development speed but for a change, the rewards associated with the risk endured are nothing short of overwhelming. An EJ200 F414 class reliable engine is a must for China.
Such a WS-19 could also help in the fast development of Carrier borne UAVs ( operating aboard Type 076).
Here is an idea that I think China should explore. Instead of building large turbofan engines, why not develop a turbine electric hybrid engine. Electric engines are more efficient and simpler to make than large turbofans. The downside to electric is the battery. So instead of using batteries, why not use a small turbine engine from a helicopter to generate electricity which is used to power the electric engines which drive fan or propeller? Wouldnt this be a much simpler and elegant solution to leapfrog ahead?
If you’re using a secondary turbine to generate electricity to turn a fan, how is that an improvement from directly turning the fan with your primary turbine? You’re taking a hit on both conversion and weight efficiency in that setup.
Weight wise, it balances out. One helicopter turbine can generate enough electricity for 4 electric motors. The electric motors are going to be much lighter than turbofans, while providing the same thrust, since most of energy from turbofans are wasted as heat. There is definitely more room to improve the efficiency of electric motors. So you might be able to get an ultra light weight and efficient engine setup.
Are you suggesting a full electric fan driven propulsion? If you are, then I think I misunderstood the proposal. If we’re talking the electric fan generating all the propulsive force the problem is you will probably have to take a pretty hard penalty on top speed.
Yes that is what I am proposing. All propulsion is provided by electric fans. China has more experience with electric motors,maybe its possible to increase the power of the electric fans, so max speed can increase? I guess for large transport planes, speed isn't as big of an issue.
I think it's a promising route to explore, maybe even easier than trying to catch up with GE or RR in trying to build ultra efficient turbine engines.
SamuraiBlue
Captain
Sorry but this defies basic mechanical principle in which with transfer of energy there will always be a loss, so a turbine rotating a propeller directly, the axle torque will always be stronger than rotation being transferred to various shafts at the same rotating speed.
An interesting idea will be to combine a tubine engine with the electric plasma engine that I posted in the past.
The turbine engine provides electricity and initial combustion and then dump the combustion exhaust into a secondary chamber and then heat up the exhaust with the electric plasma generator to super heat the exhaust resulting to further heat expansion of the exhuast resulting to further thrust.
Basically it should work like an afterburner without dumping more fuel into it.
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Hitting transonic and supersonic speeds isn’t just a matter of fan power. Due to aerodynamic dependence your fan can only push air up to Mach 1, at best, and as an air breathing reaction mass engine you can only go as fast as how quickly you can propel an airstream. Compressor based designs can get around this by getting extra propulsive velocity via increasing pressure, but on the other hand have much *higher* energy density requirements. The advantage of combustion for compressor based designs is that as you’re trying to drive the airstream beyond transonic speeds heat energy becomes much more efficient than mechanical energy at generating higher pressures and thus driving the velocity of the airstream, and your combustion reaction generates a lot of free heat to use, especially given that you’re basically getting part of that energy via the free stream via oxygen from the atmosphere rather than carrying it. With an all electric design you’d need to find another source of heat to get comparable levels of propulsive velocity, and you can’t get the freebie of extra heat energy provided by your environment.
I think for what it’s worth you don’t need a denser battery or a secondary electric generating turbine to get around the energy density problem for an all electric transonic design. Fuel cells theoretically speaking should be better than both. But if you don’t want a hard cap below transonic speeds you’re going to need to find an efficient way to convert enough electric power to heat that gives you total system efficiency comparable to your combustion driven turbines at transonic and supersonic speeds.