Originally Posted by PBL
But interpreting you more widely, if the aircraft component primarily associated with the momentum reduction is the reverser itself, why would anyone want to call the resultant force "inlet ...", or or "intake...." anything? Why wouldn't they call it "reverser vane load"?
Originally Posted by Guppy
Because that's not the case.
I'll let you argue that with HN39.
Originally Posted by Guppy
If blowing exhaust gasses on cascade vanes or reverser buckets were to produce a retarding force, we'd have a whole new law of physics at play (and we'd be revisiting Newton's third). We could transfer that new law to sailing ships, and let the ships use giant fans to blow on ship-mounted sails to propel the ship along.
New laws of physics? I think we can do that with the ones we have. I can think of at least two designs where that would work. Not that it would necessarily be efficient, mind.
It would work for airplanes also. Mount the engines in the other direction, blowing onto the wing. Smoothly, of course. And rise into the air vertically. Better idea: move the wing in the air. You'd probably have to make it go round and round to do that though. Wait, hasn't somebody had that idea already?
Originally Posted by Guppy
Using a rearward engine-produced force to act on an engine-mounted or nacelle-mounted reverser mechanism to produce a greater retarding force is nonsensical.
Really?
Originally Posted by Guppy
You can certainly attempt to separate components of drag into lip drag, form drag, intake drag, or any number of other components of the ram drag equation (already provided, here)
So now you are saying that "intake drag" is "a component of the ram drag equation", whereas, before, you were saying that ram drag and intake drag were two names for the same thing:
Originally Posted by Guppy, note 13
you're left with ram drag, also referenced as inlet drag or intake drag
But wait a minute ...... you weren't only saying it before, you're saying it again now!
Originally Posted by Guppy
We're considering intake flow (hence, the acceptable use of "intake drag" or "ram drag," used here interchangably), not exhuast mass airflow.
So, if you would please, I'd like you to decide. Is "intake drag" a "component" of "ram drag"? Or is "intake drag" identical with "ram drag"? You can have one, but not both. And when you've chosen, I'd like you to stick with the choice.
Originally Posted by Guppy
If we are to consider airflow through the exhuast on a high-bypass turbofan, we can only consider it as a portion of the mass airflow through the nacelle inlet; it's the mass airflow through the inlet that accounts for the retarding force in reverse operations.
Well, no. There is also the mass of accelerated air which passes just outside the cowl, which will be arrested in the x-direction by the reverser exhaust. That loses momentum also, so that is going to enter the momentum-loss equation too.
PBL