Jump to content

Fuel Pump Vent


Wing Nut

Recommended Posts

Sorry not true. The new Corona pump can have some oil drips past the pump shaft seal. It is in the manual and has a value. A drip or ooze is normal, but some may not drip too. It isn't even across the board.It may have a drop or two, but not a steady drip.  Where you put the vent tube can affect this.

This was true with the old Pierberg and AC pumps, but not the Corona.

I know this because I'm typing it while sitting in my updated Heavy Maint. Rotax class.  

Link to comment
Share on other sites

If your pump is leaking fuel, it's in a failed state - brand new or old.

 

The ignition temperature of gasoline is about 495° F.  Your exhaust will make a fine ignition source.

 

True, but gasoline begins to vaporize at 89°F.  A drop will flash off to vapor before it ever has a chance to ignite.  You'd have to dump more gas onto the exhaust than could quickly evaporate.

 

If this were not the case, you'd have a lot of CT engine fires,  since the carbs are directly over the exhaust.  That drip tray won't catch everything.  I flew the 1400nm back from Arizona with both carb float bowls leaking a bit (they probably leaked on the way out, too), and never turned into a fireball or saw any evidence of combustion under the cowl.

Link to comment
Share on other sites

Andy,

 

Here is gasoline MSDS sheet.  The vaporization starting point for gasoline is -45F. Gas won't burn below this point as it does not produce any vapor. You must have vapors for gas to burn. Anything above that and gas will produce a vapor and can burn. So at your 89F gas is extremely flammable. Vapor concentration needs to be between 1.4% and 7.6%. Below 1.4% it is too lean a mixture to burn and above 7.6% it is too rich and needs more oxygen. In almost all places in the US and almost anytime of year gasoline will be ignitable because most places aren't below -45F.

 

http://www.archgh.org/default/RiskMgmt/MSDS-Gasoline.pdf

Link to comment
Share on other sites

Please look at my above post about dripping from the Corona fuel pump. I original wrote fuel and it should have been oil. I was in class and thinking fuel pump and wrote fuel. It is oil that leaks around the fuel pump shaft past its seal.

 

Sorry for the mislead.

Link to comment
Share on other sites

Andy,

 

Here is gasoline MSDS sheet.  The vaporization starting point for gasoline is -45F. Gas won't burn below this point as it does not produce any vapor. You must have vapors for gas to burn. Anything above that and gas will produce a vapor and can burn. So at your 89F gas is extremely flammable. Vapor concentration needs to be between 1.4% and 7.6%. Below 1.4% it is too lean a mixture to burn and above 7.6% it is too rich and needs more oxygen. In almost all places in the US and almost anytime of year gasoline will be ignitable because most places aren't below -45F.

 

http://www.archgh.org/default/RiskMgmt/MSDS-Gasoline.pdf

 

To the point of my post...do you think a drip of gas on to the exhaust of a running engine would ignite? 

Link to comment
Share on other sites

The autoignition point is 536F. The flash point is -45F. The exhausts are much hotter than either. Using my heat gun, I was clocking over 800 degrees at higher power settings... and that's with cowling off. Most definitely enough to ignite.

Link to comment
Share on other sites

Look at your EGT temps in flight and tell me what you think the exhaust metal temps are right out of the head and right under each carb.

 

I do agree that it may take the perfect storm to ignite and a drop will more likely evap, but in flight fires have and will continue to happen. Why play Russian Roulette if there is absolutely no need.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...