Hi guys, What variant of the CFM Engine will the NGX be based on, or will one of the options be the different engines (each with different thrust) that are available on NGs?cheers

Adding to Dylan's question, I have a rather technical query. As I was saying in the thread "Impressions of the NGX", I'm going to do a test flight following a schedule from CAA, the CFS-300, and one of the phases of the test requires me to know which type of combustor is there in the engine, so that I can elect the appropriate altitude for the engine relight test (check page 19). So, is it a single annular combustor or double annular combustor? Or is this characteristic not modelled at all?

Hey I guess these one:CFM56-7B24 >>>> 24.200 max static thrust lb.st >>> bypass ratio 5.3CFM56-7B26 >>>> 26.400 max static thrust lb.st >>> bypass ratio 5.1CFM56-7B27 >>>> 27.300 max static thrust lb.st >>> bypass ratio 5.0Its just a Guess

CFM56-7 has a DAC and you can have one on the CFM56-5B apparently (and probably on the F108 variants I would guess). As far as flight sims are concerned, it doesn't matter that much, because a DAC is intended to reduce emissions and save fuel, and since there are no emissions on your simulated aeroplane and fuel doesn't cost you anything, it makes no odds. The point of a DAC, is that when jet fuel and oxygen mix together and burn, you get nasty emissions being produced, the more efficiently and faster the fuel burns, the less crap is produced to get thrown out in the exhaust. A DAC can mix the two more efficiently.Here's a link to a diagram of what a combustor is, the reason it is called an annular combustor is simply that it is arranged in a ring, which is what annular means: https://engineering.purdue.edu/~propulsi/propulsion/jets/basics/burner.htmlA Dual Annular Combustor, as you might expect, has two sets of combustors (arranged concentrically in two rings) in order to burn the fuel more efficiently, although both combustors only kick in at certain engine settings.Here's the CFM page about the technology:http://www.cfm56.com/press/news/cfms+advanced+double+annular+combustor+technology/198It would be easy enough to simulate it in FS, since all you do is type in the rate at which the fuel burns and a few other values in the config file and hey presto, you are simulating a DAC. When the PMDG 737 comes out, you can simply look on the FS load screen and it will tell you what engine it is meant to be simulating.Al

Thanks for the answer, Al. Looks like I'll have to relight the engine at FL270 anyway because, according to CFM, GOL doesn't have DAC in their aircraft engines. If I understood that right, the type of combustor don't seem to make any considerable difference in the virtual world. The only noticeable changes would be in fuel burn and EGT. As you said, we don't have to worry about pollution nor the price of fuel in FS :(.Now, let's go off topic for minute. I have to say Al, you seem to know everything about aviation, from the simplest to the most technical subjects. Your intelligence is my target; one day, I want to know half of what you know about aviation. It's been good to have you around because I've learned a lot from you, and I bet others think the same. Hope you can keep teaching us, mere flight simmers, for years to come. It's not much, but just thought I should say something to thank you for sharing your knowledge with us. All the best for you, Al.

Nah, I just make it all up. :( Al

:( :LMAO:I bet you do.

CFM56-7 has a DAC and you can have one on the CFM56-5B apparently (and probably on the F108 variants I would guess). As far as flight sims are concerned, it doesn't matter that much, because a DAC is intended to reduce emissions and save fuel, and since there are no emissions on your simulated aeroplane and fuel doesn't cost you anything, it makes no odds. The point of a DAC, is that when jet fuel and oxygen mix together and burn, you get nasty emissions being produced, the more efficiently and faster the fuel burns, the less crap is produced to get thrown out in the exhaust. A DAC can mix the two more efficiently.Here's a link to a diagram of what a combustor is, the reason it is called an annular combustor is simply that it is arranged in a ring, which is what annular means: https://engineering.purdue.edu/~propulsi/propulsion/jets/basics/burner.htmlA Dual Annular Combustor, as you might expect, has two sets of combustors (arranged concentrically in two rings) in order to burn the fuel more efficiently, although both combustors only kick in at certain engine settings.Here's the CFM page about the technology:http://www.cfm56.com/press/news/cfms+advanced+double+annular+combustor+technology/198It would be easy enough to simulate it in FS, since all you do is type in the rate at which the fuel burns and a few other values in the config file and hey presto, you are simulating a DAC. When the PMDG 737 comes out, you can simply look on the FS load screen and it will tell you what engine it is meant to be simulating.Al

It seems to me some engine parameters would change, wouldn't they? Temps?EDIT: I investigated a little further. Search double annular in this forum and you'll come across a post in the "Externalities and the NGX" thread. Martin ("FirstOfficera320") posed a few questions about this. While it would by no means change my experience with the NGX, it was a neat question. Martin posted a picture of an NG or A32x with one engine testing DAC. The difference in EGTs of the SAC vs. DAC engines were noticeable.

I daresay they would, but again, if it required any sort of really complex changes to the aeroplane, it probably would not have been certified for use on it, since it also gets used on the A320. CFM will have developed it for those two markets more than anything else, and they won't want to have made life hard for Boeing or EADS. Presumably there are some FMC tweaks necessary and probably some tweaks to the calibration of gauges or whatever, but I don't imagine it makes a vast amount of difference to the pilots in terms of operation. After all, you don't have to know how a twin carburetor works to drive a car, and it's basically the same thing.Al