After the last flight I had to find out at home that the UAT was almost...
Uwe B.
After the last flight I had to find out at home that the UAT was almost completely filled with air. The Emcotec tank filling valve has probably not closed completely. The air got in here due to the negative pressure. It was damn close to a turbine stop. To protect against a fall caused by such a stupid thing, I have now installed a locking valve.
2 Comments
That is fascinating! Does your fill line push fuel to the main tank through the UAT? If so, I wonder how air gets trapped? BTW, what turbine are you using?
Very good your request. I have a wren 44i : Practical rpm range – 4,000 to 18,000rpm, 3.24Nm, 7hp (5.3Kw) (engine to max 195k rpm)
After several turbine stops in the past, I worked very intensively on the fuel system.
There is also a very good tutorial video - turbine technology for beginners part 3 hoses..filters..air bubbles
https://youtu.be/Df00xLpnUV4
But I didn't take the -Emcotec refueling valve- into account. The manufacturer has recently added this note to the description:
DANGER
In the case of jets with several tanks (hopper tank), air can be sucked in under certain circumstances due to the resulting negative pressure. In this case, a ball shut-off valve can be looped into the tank line, which enables it to be closed securely.
It is likely that pollution occurred as a result of careless refuelling. (see schematic description)
With this arrangement, I can check for leaks in the vacuum line while emptying.
But the tank valve is not included in this leak test. 😞