A320 Neo flight

[Gandahar]

Damn those engines look big compared to the old ones

https://www.youtube.com/watch?v=KSuXpcXC7zk&fe...

[Starfighter]

The engines are one of the prime advantages that NEO has over Max, it has the ground clearance to take bigger engines like Leap rather that the Purepower unit on 737 Max.

[David87]

Forgive my poor knowledge of these things, but why are engines that have a physically bigger diameter advantageous? Obviously these are much bigger than the old A320 and 737 engines, but surely that just means more weight and more drag? Where are the positives?

Also, has anything else been updated or is it literally just a pair of new engines?

[mackie1]

I'm guessing noise?

[JeremyH5]

The new engines are a bigger diameter than the old to allow a higher bipass ratio. More air goes around the engine core giving more thrust for the same fuel burn; more efficient.

[Starfighter]

David87 said:

Forgive my poor knowledge of these things, but why are engines that have a physically bigger diameter advantageous? Obviously these are much bigger than the old A320 and 737 engines, but surely that just means more weight and more drag? Where are the positives?

Also, has anything else been updated or is it literally just a pair of new engines?

What Jeremy said...

Better bypass allows less fuel for the same thrust or more thrust for the same fuel, either way gives better overall performance. The drag for the increased cross sectional area is minimal as most of that cross section is actually "pushing".

David87 said:

Also, has anything else been updated or is it literally just a pair of new engines?

The new engines are a massive improvement over the old ones (CFM 56 and V2500) but these are many other changes. 737 is getting alot of new fly by wire technology which reduces weight and there are changes to the wing profiles and due to the space problems.other aerodynamic surfaces which reduce drag. There are a lot of changes to the engine nacelle to improve airflow and reduce noise. Your choice as to whether you call this part of the engine of the airframe. I would expect better cover latches as well to stop the covers opening in flight!

The 737 is still limited by the main undercarriage situation. It was designed with low bypass engines and so sits low to the ground. To increase the ground clearance would require moving the main gear further out on the wing and that is basically the heart of the airframe. As far as I recall, the 737max will still not have full main gear doors.

[LHRFlightman]

Fuel efficiency.

But also noise. The NEO is actually a 'noise exempt'/QC 0 aircraft. That has many advantages which I haven't got time to explaine right now. Look it up if you're really sad, I mean keen.

[Steve vRS]

Sorry to show my ignorance here. On a high bypass turbo fan engine, is a lot of the thrust cold i.e. from the compressor fan at the front rather than as a result of the hot gasses from the combustion chamber?

Steve

[JeremyH5]

Steve vRS said:

Sorry to show my ignorance here. On a high bypass turbo fan engine, is a lot of the thrust cold i.e. from the compressor fan at the front rather than as a result of the hot gasses from the combustion chamber?

Steve

Yes it is. Cool huh?

[Mave]

Steve vRS said:

Sorry to show my ignorance here. On a high bypass turbo fan engine, is a lot of the thrust cold i.e. from the compressor fan at the front rather than as a result of the hot gasses from the combustion chamber?

Steve

Yes. As the bypass ratio increases,so does the ratio of fan thrust versus core thrust, so less kinetic enery thrown away hence better propulsive efficiency.