Just_a_fan wrote: ↑04 Aug 2023, 08:30
organic wrote: ↑04 Aug 2023, 00:16
If they're venting air out of that outlet then they're drawing it from the inlet. So for a given amount of cooling they have to make the inlet larger. So that takes away from the amount of air going to the undercut (given they'll need a larger inlet for the same amount of cooling) and the net benefit is what?
Except the RB uses a very large bottom lip on the cooling inlet that totally separates the flow to the inlet from that going to the undercut. They can change the inlet without affecting the undercut flow.
Agree that the entrance is well separated for proportion of air above vs below by the leading edge sidepod design.
Also, the air entance appears to be the most effective and elegant (very efficient too) way of control for that function. Dealing only with the top side airflow for discussion purposes, at some point in speed range the internal reaches a peak that is exceeded by exterior (simple logic of the two routes) at which the entrance starts to flow more air over the top rearmost lip of the aperture. They dont need more flow internally, hence no need to bleed it out the back as conspiracy theory seems to have it on this rear vent.
This arrangement is very common on aircraft, how the air in excess of that going down the entrance aperture is dealt with effectively with minimal disturbance to the outside airflow over the top of surface.
It's usually up the other way though for aircraft engine intake, and causes lift when the entrance is slower than outside airflow. If there's a "secret/trick" that's missed by other dedigners its this aspect I believe, with at least the potential to give no lift and the possibly downward loading while doing this.
You coukd call it a "Zero" lift air entrance, see what's happened there
being completely the opposite to a wing form above the significant airflow entrance that some other prominent team runs
People on the greater wide Internet seem to spend ages proffering their research of finding "tricks" when things like this are in plain sight, but they don't understand them.