411A
The engine cowls on large American-made 4-engine piston transports were of the NACA pressure design, thereby increasing engine cooling airflow....greatly.
What's the difference between the NACA Cowl and NACA Pressure cowl? When was the latter first developed?
SNS3Guppy
most installations use pressure cowls with baffling to control airflow for maximum cooling. In most cases, cowl flaps are also used to vary the airflow and increase cooling when needed.
Understood. What was the first time the technology to produce a radial installation with pressure-cowls -w- baffling, and cowl flaps came into being? What was the first aircraft to have such a set-up?
The 4360 used a gradual offset to the right, or clockwise, as seen from the front, with airflow spiraling clockwise aft. An intricate baffling system and induction system was used to provide what limited airflow there was, to reach the rear cyclinders.
What made the baffling and induction system so intricate? Did the technology exist before this to produce a three to four row radial?
Old Ag
Careful cylinder offset was also necessary to combat vibration inertial forces.Limiting vibration in large double row radials requires masterful engineering with master rod offset, crankshaft design, vibration dampers, gear reduction and propeller selection etc. An ideal offset for cooling meant a slight compromise on the offset for vibration. Vibration in engines like the R2800 really drove much of the deign.
When did the technical capability first come along to be able to balance all of these variables to allow a three/four-row radial to exist?