yep -the air has to be moving in response to the airscrew direction.
The flow pattern tho-------- has too many factors involved to see how much pressure is going BACK vs going sideways.
It is there and will be different on every plane and at different airspeed and at different power settings . That is why trim tabs and such were invented.
On a related note -- cooling our model engines is also related to the spiral output of the airscrew .
The prop does not -as some think - blow air into the cowl inlets.
It just stirs up things .
Then
The air flowing over the cowl, creates a low pressure at outlets/vents/louvers-which is replaced by air in the cowl-so the inlets of the cowl only provide a make up source for air flowing thru th cowl.
On full scale the cylinders are well ducted to really make the airflow hug the engine fins --and PULL the air thru to th outlet.
On my CAP and my Edge -I tried two other tricks -whch seem to work:
the Cap got vents added alon top the cowl - to receive air further from the hub area air and above the engine - this helped the internal flow to start above the engine -then down and out . Made an instant difference in temperatures .
On my EDGE-- I simply added a extension to the front of the cowl - to again extend the distance from the prop -to the cylinder (located at lower left of picture) and the scale inlets - the idea was the same to hopefully gain access to air not simply stirring at the hub.
Spiral flow is spiral flow and the prop twist at the hub area does really nothing to add rearward flow of air- so These approaches were done to help create some positive pressure in this area. The Cap is flowna lot at shows etc., now by a friend and is constantly staggering along at high AOA and the engine HAS to be kept cool .