Kevin:
The only change would be that the fuel
flow during taxi is only about 4 GPH.
The other question is the speed must not
only push the water thru the tube but must push the water up 1” to get to
the trap. It seems I now have to go faster to get water to the trap.
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Kevin Kossi
Sent: Saturday, May 12, 2007 8:58
PM
To: lml@lancaironline.net
Subject: [LML] Re: IO-550 fuel
injection
OK, lets have some fun with numbers:
I would think the volume of air flowing through the ram air vacuum
breaker tube would be equal to the volume of fuel being drawn from the tank.
To figure out the speed at which the make-up air is flowing through
that tube:
Provided you are drawing from one tank at a time:
If the engine is using 15 Gallon per hour, at 231 Cu/In per gallon,
thats 3,465 Cu/In per hour, divided by 1728 to get Cubic Feet Per Minute, which
it 2.00520833 Cubic Feet Per Hour
Divide by 60 to get Cubic Feet Per Minute, that's .03342014 CFM
(I need to convert tot CFM because my air velocity calculator only
works in CFM)
I put the following into my air velocity calculator:
Tube inside diameter: 0.139
Velocity: 317.14 FPM - Feet per minute
Friction loss: 0.068985 " WC
Now if I I use 5,280' in a mile and divide that by 60 to get Feet per
minute, I get 88 FPM for one mile an hour, divide our 317.14 FPM velocity by
88, we get 3.6 Miles per hour.
I would think under the right conditions that might be enough velocity
to suck some water up the tube.
Kevin Kossi
Legacy 80%
10:1 Single Lightspeed
Single Slick Mag
Hartzell
HC-H3YF-2UFX/FC7391D-3X.
Full feathering,
counterweighted, 3 blade