Sorry, gotta ask, this has always bothered me - my pilot acquaintance who flies helicopters said what kills engines is not hours of operation but rather start-stop cycles, as the engines experience the most stress during spin up/heat up, and regular operation is comparably rather gentle on the engine. Yet I never see this metric mentioned, and engine life is always measured in thousands of hours.
Modern Western engines use ‘on-condition‘ maintenance, which means that the engine is inspected regularly and maintained according to actual usage rather than a specific schedule– there is no requirement for scheduled engine removal and overhaul like with Russian engines. Engine lifespan could match the airframe - commercial CFM-56-3s have reached 40,000 hours 'on the wing' i.e. installed on the airplane. EJ200 gives a figure of 1200 hours 'on the wing' and engine should last the life of the Typhoon. I haven't immediately been able to find similar metrics for modern US engines.
First time that I have heard that the J-50 is the Naval variant and the J-36 is the land based variant Scott Kenny, I had thought that both variants would be bought by the PLAAF and PLAN.
Being fair, there's a lot more performance metrics to an engine than lifespan, if the Chinese can achieve an engine performance similar or even better than F-119 albeit at perhaps 60 percent of the total engine lifespan with the WS-15(There's been a recent statement that WS-15 have a better performance envelope than the F-119, see attached below). It wouldn't really affect the aircrafts actual performance in flight but only hamper the lives of the ground crew a bit by needing slightly more "regular" engine replacement. Do note that western engines with lifespans up to 8000 hours are meant to be replaced once every ~30 years, so 60 percent of that would still be 18 years. Perhaps by the time the very first batch of WS-15 are nearing the end of their designed lifespan, China would have caught up to the bleeding edge on engine technology if not already before.
This unit ensures the operation of the Irbis radar. He also works on the B-70 during the entire flight.
aerosila.ru
The fuel mass flow is almost negligible compared to air mass flow.
It depends. You're removing power that would otherwise be available for the compressor so it impacts surge margin and hence high altitude performance. If you can accept this then it seems possible to double the electrical generation capacity from "normal" from multiple examples. But it all depends e.g. newer engines generally have higher electrical generation designed in from the start so doubling this is unlikely. The loss of thrust from the engine is very small - it's more impacting the operability envelope.
It's largely because older engines were designed under "replace X part every Y many hours" or "Inspect every Z many hours" and there are still a LOT of those older engines in use in helicopters and general aviation.
As an example, the P-8 Poseidon has a pair of 27,000lb thrust CFM56-7B27A engines. Those have double capacity generators installed to power the radar. 90kVA generators on the civilian 737NGs, 180kVA on the P-8. I believe the E-7 Wedgetail has the same setup, but am not finding a reference for that quickly.
The "everything LRU" approach. And just about many current Chinese commercial products. Good enough, if faulty, buy new. It's an interesting approach and has proven to outcompete legacy brands (Tupperware etc).
Not sure, what I heard/read was that the pilots were going to and from max thrust a lot more often than was happening in the J79-powered planes.
True, but it is is not a dramatic increase in mass flow. With stoichiometric being around 15:1 air to fuel, and the main combustor already burning around half of the O2, the AB will only be adding about 1/30th to the total mass flow. A higher bypass engine would add more fuel, but it is still on the order of 5% added mass flow.
It was the reducing power toward Idle to slow down to corner velocity that was the surprise. The increased performance of the F-15 and F-15 compared to the F-4 which was usually at Mil or Max AB in a fight that greatly increased the cycle count.
Except that a jet engine only burns about 1/4 the ingested air, the rest is used for keeping the turbines from overheating.
A F100-220 has a sea level airflow of approx 224 lbs / sec. At Mil power, burns a little less than 4 lbs /second fuel flow. At Max AB, burns about 14 lbs / second fuel flow. So about 10 lbs / sec fuel added to the 224 lbs / second airflow. So about 4.5% added mass flow from the AB fuel addition.
Well, 1990s Russia is not only properly reliable AL-31FN, it is also AL-41F (article 20) on mig 1.44 in the air, not just on engine test aircraft.
How does Chinese translate word demonstrator and prototype in their language anyway?
A tech demo would be "技术验证机" or just referred to as demonstrator "验证机." A prototype would be "原型机."
All goods. FYI, a production aircraft would be called "量产机."
None, they didn't mention much on the nature of the aircraft other than calling it a 6th generation fighter. So I guess debates on if this is a JH (Fighter-Bomber) or a H (Bomber) is out of the window now.
He's Assistant Minister of Foreign Affairs according to https://www.mfa.gov.cn/eng/zy/wjrw/lrfbzjbzzl_665553/202405/t20240531_11367657.html
Still, words from a high-ranking official are still very important if they officially announce something. The main takeaway point here isn't about any engineering aspects (He doesn't really mention them anyways only calling it a 6th generation figther), it's about the fact that they are confirming its indeed a fighter and not a bomber or fighter-bomber. Also, someone like him fumbling a bomber or strike aircraft as a fighter seems very unlikely in a publicized speech (Which are probably double checked by experts and stuff), so I feel like this is genuine official confirmation of a fighter.
That is an interesting conundrum. Your signature is "Everybody lies" but then stand by the words of a member of the Foreign Ministry of China which has about as much credibility as Baghdad Bob...
I do not see a reason for him to lie, it's not like they just came out with "We have flown a 6th gen prototype" without any proof or prior announcement. This is after basically everyone saw the new planes unless your suggesting those are CGI, I don't see where your getting this.
