P47 From the manual

[Randy1]

I was browsing the manual linked to the WiKi AH on the P47 this morning and found some things I did not know.

They had a pilot Relief Tube.  Never thought about that.

The six 50s was noted as the standard load-out from a design standpoint.

No spins over one half turn on purpose.  No snap rolls over 150IAS(I think)  No inverted flight.

This one threw me.  Emergency take-off was to use diluted oil.  What do they mean by diluted oil?

[colmbo]

This one threw me.  Emergency take-off was to use diluted oil.  What do they mean by diluted oil?

Most older aircraft had oil dilution systems on them for use during cold weather starts.  The system used fuel to thin the oil so that it could circulate while cold, the fuel would cook off as the engine ran. 

[bozon]

They had a pilot Relief Tube.

Was that like a children relief, but for hungry homeless pilots?

[gyrene81]

Was that like a children relief, but for hungry homeless pilots?

[earl1937]

Most older aircraft had oil dilution systems on them for use during cold weather starts.  The system used fuel to thin the oil so that it could circulate while cold, the fuel would cook off as the engine ran. 

Correct and if I am not mistaken, the RAF used that ability quite often in the winter months, when scrambling to intercept the "Hun".

[Randy1]

Thanks for the answers on the oil dilution.  Lot of interesting stuff in the things left out of AH albeit I would not want most of that added in.

[Widewing]

Most older aircraft had oil dilution systems on them for use during cold weather starts.  The system used fuel to thin the oil so that it could circulate while cold, the fuel would cook off as the engine ran. 

Indeed, but if you were forced to use the oil dilution system, it meant sumps and strainers at the first reasonable opportunity. Mixing fuel with the oil meant that every little bit of carbon would be found in the strainers. Enough and the strainer wouldn't flow, inducing the bypass valve to open. Before I'd use oil dilution, I'd have it towed into a warm hanger, if at all feasible. We delayed several hours on a couple of occasions. I didn't want my engine mechs working late hours if I could avoid it. The coldest I had to deal with was Bangor, Maine in January.... About -10°F with -20°F wind chill.

[Ack-Ack]

I wonder if the Soviets used an oil dilution system for their aircraft on the Eastern Front during the winter months or was it just too cold for such a system to work properly?  In Hartmann's book, he mentions that they had a tough time getting their planes to start because of the cold until a captured Soviet pilot mentioned that the Soviets would light fires under the engines to get them warm enough to start.

ack-ack

[climber]

I've read a bit on the oil dilution systems in American aircraft.  This is modeled in the A2A add-on aircraft for FSX.  If the pilot knew he would be starting the aircraft up when the temps were low he would run the oil dilution prior to shutdown in order to move some fuel into the oil thus preventing the thickening that comes with cold temps.  While running the dilution it was important to also operate the auxiliary/ emergency fuel pump to maintain fuel pressure going to the engine. 

Another option was to have oil warmed indoors and added to the engine prior to startup but this could be a slow procedure for scrambles. 

[morfiend]

I wonder if the Soviets used an oil dilution system for their aircraft on the Eastern Front during the winter months or was it just too cold for such a system to work properly?  In Hartmann's book, he mentions that they had a tough time getting their planes to start because of the cold until a captured Soviet pilot mentioned that the Soviets would light fires under the engines to get them warm enough to start.

ack-ack

  I read a similar thing but they also said the captured Russians taught them to use fuel to thin the oil for emergency takeoffs!  So although I haven't read about the Russians doing it or using that technique it would be a pretty sure bet they did.


   

[colmbo]

Indeed, but if you were forced to use the oil dilution system, it meant sumps and strainers at the first reasonable opportunity.

I've heard that another problem was the dilution system washing oil off the cylinder walls, etc. with a resulting loss in lubrication.  It's the kind of system the military could use with their big budget but a civilian operator would shy away from due to the long term issues.

[branch37]

I've heard that another problem was the dilution system washing oil off the cylinder walls, etc. with a resulting loss in lubrication.  It's the kind of system the military could use with their big budget but a civilian operator would shy away from due to the long term issues.

Its the same as in any modern engine.  If fuel is leaking into your oil, it can result in the engine getting too hot and causing major damage.