KRviator
Well Known Member
G'day folks.
Was lost in thought last week routing the pitot/static lines for the Dynon and it occurred to me that the Dynon pitot has the second port to provide a reference source of pitot pressure at high nose attitudes might prove useful for "other" things as well.
That night I was browsing a Kiwi Cri-Cri builder's log and saw that he's using a very light pressurisation of the fuel tank to deliver fuel to his tiny twin engines. And also pondered if building a Cri-Cri was the cheapest way to get 500 Multi...
Now, I've got an H2AD donk to hang on the front of my -9A and won't be running the engine driven fuel pump and it occurred to me that if I was to install a second pitot tube on the left wing and feed the ram air pressure to the vent lines of the tanks, the resulting pressurisation of the tanks would ensure positive fuel flow to the Rotec TBI at any speed above the stall.
Another builder of a LongEz has thoughtfully published a Pitot pressure vs KIAS table and that shows you won't reach so much as 1PSI until 205KIAS, but even at 50 knots you've got above the 0.05PSI minimum required for the Rotec TBI.
It seems this route would alleviate the 2nd pump and if you wanted true redundancy the 2nd battery for said pump as well.
What are your thoughts?
Was lost in thought last week routing the pitot/static lines for the Dynon and it occurred to me that the Dynon pitot has the second port to provide a reference source of pitot pressure at high nose attitudes might prove useful for "other" things as well.
That night I was browsing a Kiwi Cri-Cri builder's log and saw that he's using a very light pressurisation of the fuel tank to deliver fuel to his tiny twin engines. And also pondered if building a Cri-Cri was the cheapest way to get 500 Multi...
Now, I've got an H2AD donk to hang on the front of my -9A and won't be running the engine driven fuel pump and it occurred to me that if I was to install a second pitot tube on the left wing and feed the ram air pressure to the vent lines of the tanks, the resulting pressurisation of the tanks would ensure positive fuel flow to the Rotec TBI at any speed above the stall.
Another builder of a LongEz has thoughtfully published a Pitot pressure vs KIAS table and that shows you won't reach so much as 1PSI until 205KIAS, but even at 50 knots you've got above the 0.05PSI minimum required for the Rotec TBI.
It seems this route would alleviate the 2nd pump and if you wanted true redundancy the 2nd battery for said pump as well.
What are your thoughts?