Author Topic: SCAT duct to nowhere?  (Read 1429 times)

Clarke Tate

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SCAT duct to nowhere?
« on: June 26, 2014, 09:53:24 PM »
Hello,
Does someone have any insight as to what these SCAT ducts originally did?
I had my lower cowl off today for the first time to clean and rotate plugs.
There are screen openings under the spinner that lead to the SCAT ducts to nowhere.
The mechanic wondered if it was some type of cooling air toward the oil reservoir.
I just acquired this Culver Cadet, that was originally an LFA, last September.
The aircraft now has a Continental C-85-12F after having two different Franklin engines prior to
this engine being installed in 1983. The lower cowl has welded aluminum areas where
the Franklin exhaust would have been (slightly blurry as my camera had been manual mode for another photo).

Bill Poynter

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Re: SCAT duct to nowhere?
« Reply #1 on: June 27, 2014, 01:14:37 PM »
LFA's and LCA's both had openings below the prop for the purpose of oil cooling.  The LFA had sort of an oval shaped hole, while the LCA had a rectangular duct set a little lower in the nose bowl.  The Continental powered Cadets should have a baffle running under the crankcase designed to hold this cooling air along the bottom of the case.  This is important as it acts as a pretty good oil cooler.  If the SCAT tubes extend beyond the front of the case, or if this baffle is missing, you probably won't be getting adequate oil cooling.
« Last Edit: June 27, 2014, 01:22:33 PM by Bill Poynter »

Clarke Tate

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Re: SCAT duct to nowhere?
« Reply #2 on: June 28, 2014, 08:17:41 PM »
Hello Bill,
I have looked at the revised setup done in the eighties with the retrofitted Continental C-85-12F. There is an aluminum box under the engine, with air directed from the screen openings under the prop on the front cowl. This has taken the place of the original opening you mentioned. There are also SCAT connections off of this box at the front. It appears that, over time, these SCAT tubes were pulled during annuals and not redirected well toward the oil reservoir. This is not surprising as the aircraft was very minimally flown, and more a personal museum exhibit than an actively flown aircraft.
There is nothing wrong with that but it led to these SCAT hoses not being properly done as the collection went from a full time mechanic, that passed away, to another mechanic that did enough to keep the collection functionally airworthy. The owner was no longer actively flying the collection.

My mechanic and I discovered this when pulling the lower cowl for a 25 hour inspection that involved cleaning the plugs and replacing the Brackett air filter.
The SCAT ducts are now properly directed. The post maintenance flight today now has oil temperatures substantially lower on an 80F day, somewhere in the area of at least 10-15F, or more, lower.
« Last Edit: June 28, 2014, 08:20:45 PM by Clarke Tate »