F4U Oil Cooler Bypass

[Debonair]

I am reading this very good book, Wings and Warriors by Donald Engen and he mentions this feature that was on some F4Us.  
The impression i get is that it was on -1, some -4, -7 & AU-1.
The purpose of the feature was in the event of damage to the oil cooler, you could stop all the oil draining away.
Would uncooled oil be that much good to you, or would this just slightly extend engine's life?  
Maybe at a low power setting & very rich mixture you could still drive around?

[Keiler]

Some oil is definitely better than none. At least you can extend the flight duration for a while. At some point though the oil will "topple over" due to heat and irreversibly lose its ability to lubricate. At this point its STILL better than no oil, but engine will die quickly nevertheless, inevitable until you can replace the oil.

Regards,

Matt

[Karnak]

All Spitfires with symetrical radiators (Mk VIII, Mk IX, Mk XIV and Mk XVI in AH2) had a pressure valve that would close off a holed radiator.

There are a lot of quirky things with a lot of aircraft that AH doesn't model so as to make adding new models easier and less of a specific coding issue.

[Stoney74]

Originally posted by Debonair
I am reading this very good book, Wings and Warriors by Donald Engen and he mentions this feature that was on some F4Us.  
The impression i get is that it was on -1, some -4, -7 & AU-1.
The purpose of the feature was in the event of damage to the oil cooler, you could stop all the oil draining away.
Would uncooled oil be that much good to you, or would this just slightly extend engine's life?  
Maybe at a low power setting & very rich mixture you could still drive around?

I'm sure F4UDOA can give the expert answer, but here's a pure SWAG from me:

A lot of air cooled engines need the ability to regulate oil temperature.  At high speeds and/or low air temperatures, you can actually create some over-cooled conditions.  For example, as I think you know, given your piloting background, even current GA planes that are air cooled have a thermostatic bypass for the oil coolers, so that the oil actually has to exceed a certain temperature before it is routed to the oil cooler (at least on Lycomings--I'm not as familiar with some of the Continental applications).  

As far as the control on the Corsair, it may have had a technical role of regulating oil temperature, with an added bonus to the pilot of being able keep the oil cooler from spewing oil if it was damaged.  I guess my question would be how would the pilot know if the cooler was throwing oil after damage?  Given the Hog threw oil as a matter of course anyway, I wouldn't think a low oil pressure reading would be the indication to pull the handle that activated the oil bypass, unless that was a POH instruction.  The inlets on the wing root was for the oil cooler, right?  I suppose that if there was damage to the front and it was spewing over the leading edge, he could see it and activate the bypass?  I would think that you could reduce the power, and enrich the mixture as you suggested, and get the temps down to where you wouldn't need the cooler at all, which would be enough to get you home without the oil temp staying in the red.

Anyway, don't know, just guessing here.

[F4UDOA]

Debonair,

That is a very good book, Donald Engin died about 4 years ago in a glider accident. He was the head of the National Air and Space Museum for a while. He has two great F4U annecdotes in that book.

I thought the F4U could shut down one oil cooler if one became damaged but I didn't know that you could shut the flow of oil to them off completely. I guess that would buy you some time.

I have will check the manuals to see if I can find anything definitive on how that system worked.

Stoney,

Thanks for the confidence but I try to avoid the moniker "expert" if at all possible. I like to undersell and overdeliver if you know what I mean.

[Debonair]

Thanks for the info all, I always like learning more of the mintae of planes:aok

[Bodhi]

The oil cooler shut off system is a hydraulically actuated valve that is manually selected by the pilot.  If damage occurs, the pilot selects whichever oil cooler it is and pulls the corresponding handle.

The POH specifically states:

If one of the coolers is damaged, such damage will not be indicated on either the oil pressure guage or oil temperature gauge since these values will not change appreciably until all of the oil is out of the system.  Therefore during combat conditions, the pilot should check both oil coolers frequently at the trailing edge of both wings, aft of the coolers, to see if their is any oil leakage.  If oil leakage is visible, by-pass the damaged oil cooler by pulling out and turning the proper handle to shutoff position.

Also a brief FYI.  

The oil coolers are obviously located in the outboard portion (the other portion is the intercooler intake) of the wing intakes located near the center section.  There are two coolers, a left and right hand.  The oil cooler system works on an automatic or manual setting.  Simply put, the oil coolers have a sensor that is mounted on the outlet of the lefthand cooler that monitors temperature.  When the temperature exceeds 75 degrees Celsius, the cooler flap (which control the airflow through the coolers) begin to open.  The cooler flaps will be fully open when the temperature reaches 95 degrees Celsius.  In the advent of damage or failure to the temperature sensor, manual operation can be used and is adjusted according to oil temperature to ensure the oil temperature stays within established guidelines.

[Ball]

Originally posted by Bodhi
The oil cooler shut off system is a hydraulically actuated valve that is manually selected by the pilot.  If damage occurs, the pilot selects whichever oil cooler it is and pulls the corresponding handle.

The POH specifically states:

 

Also a brief FYI.  

The oil coolers are obviously located in the outboard portion (the other portion is the intercooler intake) of the wing intakes located near the center section.  There are two coolers, a left and right hand.  The oil cooler system works on an automatic or manual setting.  Simply put, the oil coolers have a sensor that is mounted on the outlet of the lefthand cooler that monitors temperature.  When the temperature exceeds 75 degrees Celsius, the cooler flap (which control the airflow through the coolers) begin to open.  The cooler flaps will be fully open when the temperature reaches 95 degrees Celsius.  In the advent of damage or failure to the temperature sensor, manual operation can be used and is adjusted according to oil temperature to ensure the oil temperature stays within established guidelines.

you are so wrong.  why don't you do some research so that you know what you are posting about before clicking 'submit'.

[F4UDOA]

Bodhi,

Thanks for the explanation, I have been sitting on my butt the last two nights with my manuals in hand and yet the information did not find a way into my brain. I need to work on that reading thing.

Thanks for curing my ADD;)