Tomas J
Active Member
I have the retrofit lockable fuel caps from Vans. I ran into a thing that made me worry, and I wonder if others have the same experience.
I flew half an hours in freezing temperatures. Everything was normal, and after the flight I set the machine in a hangar that holds a few degrees above freezing. By coincidence I opened the fuel caps after the machine has been in hagaren a few hours. When I lifted the cap of one of the tanks there was a puff, indicating there was an excess pressure in the tank.
This got me worried ... there are not supposed to be an overpressure ni the tank, as the venting should let it out. I can not understand other than that it must have been water in the aeration system that froze in minus degrees during the flight. That could have creat a vacuum in the tank, and if I have flown longer I might not come up with fuel from the tank. The lockable fuel cap is wholly tight, unlike the original fuel caps.
When the air in the tank warmed up in the hangar, instead it created a positive pressure that caused it to puff when I opened the fuel cup.
I loosened the pipes between the body and the tank and tried to catch up the liquid that was in the pipes. However, I was only getting a small portion of it and it was pure gasoline. But there may have been some water that I did not manage to catch. I can of course make sure that the pipes are empty, but I have no guarantee that there will not be more condensed water that freezes. I ponder to remove the lockable caps and use the originals that are not completely sealed and can allow air to vent if pipes would freeze again.
Does anyone have similar thoughts as me?
Sorry for my bad english
I flew half an hours in freezing temperatures. Everything was normal, and after the flight I set the machine in a hangar that holds a few degrees above freezing. By coincidence I opened the fuel caps after the machine has been in hagaren a few hours. When I lifted the cap of one of the tanks there was a puff, indicating there was an excess pressure in the tank.
This got me worried ... there are not supposed to be an overpressure ni the tank, as the venting should let it out. I can not understand other than that it must have been water in the aeration system that froze in minus degrees during the flight. That could have creat a vacuum in the tank, and if I have flown longer I might not come up with fuel from the tank. The lockable fuel cap is wholly tight, unlike the original fuel caps.
When the air in the tank warmed up in the hangar, instead it created a positive pressure that caused it to puff when I opened the fuel cup.
I loosened the pipes between the body and the tank and tried to catch up the liquid that was in the pipes. However, I was only getting a small portion of it and it was pure gasoline. But there may have been some water that I did not manage to catch. I can of course make sure that the pipes are empty, but I have no guarantee that there will not be more condensed water that freezes. I ponder to remove the lockable caps and use the originals that are not completely sealed and can allow air to vent if pipes would freeze again.
Does anyone have similar thoughts as me?
Sorry for my bad english