Fair enough.@Pags We've gone around on this before, so no need to rehash. Everything has constraints and the Navy bought all the helicopter they wanted to afford, nothing more.
Fair enough.@Pags We've gone around on this before, so no need to rehash. Everything has constraints and the Navy bought all the helicopter they wanted to afford, nothing more.
Is it even possible to develop a turbo shaft that doesn't degrade at high altitude?The big improvement to engines that could actually be used in legacy airframes is better high/hot performance (read that as less/no degradation not an increase in max output) and better fuel economy. I would argue improving the latter by a significant amount would yield better results.
No. Simple matter of how much air you can get through the hole in the front of the engine. Speed, size, density are the factors. As you go up (or get hotter, or get less dense), the less O2 you can get in that hole. The less O2 you suck in, the less fuel you add to it (lest you "roll coal" on your climb, compensating for something while looking like you're on fire). The less fuel you add, the less energy you get out of your engine.Is it even possible to develop a turbo shaft that doesn't degrade at high altitude?
Optimized =/= more power. Those engines might have a better specific fuel consumption (how much thrust you get per pound of fuel burned) at certain altitudes and temperatures.My education says I should know this but it's been awhile. I know there are types of jet engines that are optimized for high altitude performance but they suffer at low altitude. Same thing for piston engines; it's hard to develop an all around performing engine due to the changing properties of air.
ON IT.I'm asking this in the hope the answer uses simple, one or two-syllable words written at the high-school level...
Yes.How is a FADEC different from the combination of the CEDECU/HMU combination? I understand the HMU is a hydro-mechancial adjustment, and not an electrical one, but with the ECUs in the mix, does that constitute some sort of pseudo FADEC?
Take out HMU, put HMU inputs and outputs in new, more better DECU. Now DECU is FADEC.At the end of the day, the fuel has to be regulated by a valve with either system, so I'm just trying to understand where the distinction is.
Is it even possible to develop a turbo shaft that doesn't degrade at high altitude?
My education says I should know this but it's been awhile. I know there are types of jet engines that are optimized for high altitude performance but they suffer at low altitude. Same thing for piston engines; it's hard to develop an all around performing engine due to the changing properties of air.
Take out HMU, put HMU inputs and outputs in new, more better DECU. Now DECU is FADEC.
It's also hard, I imagine, to meet arbitrary specs. The most fuel-efficient operating point for a typical engine is in the higher ranges of Ng (N1). This is why singling up gives you better range (and why -53 dudes I've asked hate that their leadership won't let them shut down #3 in flight).Is it even possible to develop a turbo shaft that doesn't degrade at high altitude?
My education says I should know this but it's been awhile. I know there are types of jet engines that are optimized for high altitude performance but they suffer at low altitude. Same thing for piston engines; it's hard to develop an all around performing engine due to the changing properties of air.
I was thinking about this and the only thing I can think of is maybe if you actively control the compressor vanes then you could optimize the intake for higher PA. But as others mention, I think we're also talking about better rotor blades being just as necessary as better engines also (?).