AT-6, BT-13/15 Prop Spinner?

[mike furline]

What was the reasoning for adding a prop spinner to the AT-6F/SNJ-6 airframes after 90% of AT-6 production was already accomplished? Was there improvement in engine cooling, airspeed or fuel consumption?




Additionally I found this photo which is dated Aug. 45 and this BT-13/15 has a prop spinner. Did BT's get spinners as well during late production?
(If the date is correct I was unaware that PT's and BT's were being sold to the public by this date.)
https://collections.lib.utah.edu/detail ... _s=dha_%2A

[JohnB]

I can't say I have seen a Vultee with a spinner, but then again I haven't looked.
As far as aircraft being sold surplus before the end of the war, I have seen several instances of trainers being offered....AT-9s, AT-21s, UC-78s, and some less common types like Ryans, Timms, Spartans.

[Paul Stroud]

Saw this Vultee at Harlingen in 86

CAF Airshow 86 by Paul Stroud, on Flickr

[M-62A]

Quote: "Additionally I found this photo which is dated Aug. 45 and this BT-13/15 has a prop spinner. Did BT's get spinners as well during late production?
(If the date is correct I was unaware that PT's and BT's were being sold to the public by this date.)"

Apologies for diverting from the main query....

It should born in mind that many of the Contract Primary Schools were closed during 1944.
There are numerous examples were the AAF record cards show the PT was transferred to the RFC during late 1944.
I have seen a few entries on the FAA Registry of Fairchild PT-19s and PT-23s with a registration issue date between October and December 1944.
Check these - PT-19As N47216, N47594, N47702 and PT-19B N47642.

"Surplus WWII U.S. Aircraft" (William T. Larkins) shows 1945 examples of surplus BT-13s, also 1945 RFC Sales lists including various PTs and BTs.
Surplus sales of Trainer types clearly began well before the war ended.
M-62A

[TheBoy]

I think the primary benefit of the spinner is to protect the propeller. The counterweighted Hamilton Standard props have exposed bearings and the "piston" of the prop is a slightly delicate surface. Operating in dirty/dusty environments the spinner protects the prop. My experience is that a standard Montgomery spinner on a HS prop does nothing for speed or cooling. The backing plates are known to crack, so the spinner itself can be a bit of a maintenance issue.

[bdk]

I think the primary benefit of the spinner is to protect the propeller. The counterweighted Hamilton Standard props have exposed bearings and the "piston" of the prop is a slightly delicate surface. Operating in dirty/dusty environments the spinner protects the prop. My experience is that a standard Montgomery spinner on a HS prop does nothing for speed or cooling. The backing plates are known to crack, so the spinner itself can be a bit of a maintenance issue.

I have "heard" that they were installed by the military for use in Korea to prevent snow & ice from fouling the counterweight mechanism.

Seems to have little to no speed advantage. Reno racers had done without them recently and went faster than ever. The Montgomery 42J15621 spinner adds about 12 pounds to the nose of the aircraft.