enginehistory.org

[jjuutinen]

I have often wondered why did American designers stick so long with the circumferential type outward opening cowl flaps despite their serious disadvantages? E.g. it is mentioned in a Liberator pilot manual that lesser penalty in range is obtained by cruising in auto rich than by opening the cowl flaps fully. I´d call this a bad design. Sliding type gills would have had several advantages such lesser drag, no impact on visibility over the nose and lesser trim changes and the technology was there. E.g. when the Finnish Myrsky was being developed it was found that replacing the older style cowl flaps with sliding gills drag was reduced considerably.

Another point is spinners. How come that basically every other aircraft building nation found spinners essential for good radial installation, yet US designers stuck to spinnerless designs? I have heard someone reasoning that "spinners add complication". Oh yea, a spinner would absolutely ruin the maintainability of such simple aircraft like the Corsair. Indeed.

[szielinski]

Given the propensity of some manufacturers (eg Wright) to ignore NACA white papers on the subject, it doesn't surprise me.
It does seem unlikely that there is a valid technical reason for sticking with that drag-hungry arrangement. I haven't heard of the prop mechanism requiring prop-blast levels of air to cool it or anything.

In development, the triumvirate of money, politics and technology always puts technology last. Technology only succeeds where it is deemed appropriate by the other two factors.

In hindsight, the US probably realised they could win the war with the types in service and stuck with them - just give 'em a few points for style, they are distinctive, if nothing else.

[jjuutinen]

It seems that the opposite is true, i.e. the spinner helps to prevent oil congealing (if oil operated CSU) in the prop hub in cold weather. Never heard of prop hub overheating.