strenchable oil cooler under M.S.406?

I understand that the radiator in the Hind series aircraft had bungee assisted retraction systems and were normally flown in the fully retracted position (or had a locking mechanisim?). If however the radiator was extended or not locked and the aircraft flown inverted (aerobatics, combat) then between the bungees and gravity there would be a very loud noise as the radiator arrived at it’s stops.

These radiators were a honeycomb of copper tubes held in place by lead solder and quite heavy.

The MS 406 had a radiator that could be lowered/raised (or extended/retracted if one prefers) depending on drag/cooling requirements. It seemed to be more trouble than it was worth, because on the MS 410 (upgraded 406) and other developments the radiator assembly was fixed.

We’d say extendable or retractable, perhaps. Other examples are on the Hawker Hart family of biplanes, and apparently on the prototype Ar240s. It was a means for reducing the drag when full cooling was not required. I believe it can be seen on other types, where not specifically known, by the apparent ability of the radiator to slide within an outer shell – perhaps I am thinking of the later He111 installation here? Later designs would use a series of flaps or gills to control the airflow through a fixed radiator.

Stretchable misspelled I think. It could be lowered and raised. IIRC some aircraft had stretchable radiators.

I’m afraid ‘strenchable’ is not a word I have ever come across before. I fear it might be a translation error.

What does this oil cooler actually do that’s different? (Already guessed it cools oil)

Moggy