Hi Larry, Donald...
Yes. It's called "calibration" of useable fuel. Incidentally, if you
can get a flexable clear piece of tubing to fit tigntly in a 1/2" 2-3"
piece of copper tubing...before you do the following, try to siphon out
the garbage (water, guck, etc.) that collects along the back and bottom
of the nose tank and along the inboard lower area of the wing tanks.
(Some tanks have baffles that do not allow this to be productive).
This is an update from an off-list post 8/28/07:
Get a new Skyport "Rain-Pruf gauges with the tube over the wire.
Unless you dry, clean (with acetone) and coat old corks with epoxy, the
old shellac coating will dissolve in today's fuels allowing the cork to
become increasingly saturated with fuel. This will change your
readings over time.
Take some tape, 1/2 a old-fashioned wooden clothespin and a short (6"
or so) level up and trim the plane for "cruise" in level flight. Once
"set", tape the "uphill" side of the level to the side window sill.
Then slide the tapered half clothespin up under the "low" end of the
level until it reads "level, and tape everything at that end in that
position. When you land, your nose tank fuel level is as the transfer
pump and internal overflow establish it.
After shutting down, raise the tailcone such that the level again reads
"level, and block it on a padded sawhorse. Get a clean five gallon
bucket and a one-gallon (calibrated) container-measure. Put a "ring"
of 1/16" red tape around the gauge so that from the cockpit the top of
the wire just touches. This is "Full".
Drain one gallon at the carb. Put another "ring" of 1/16" red tape
around the gauge so that from the cockpit the top of the wire just
touches the second ring. This is "Down one gallon". Repeat, marking
"Down two gallons. Repeat, but if the gauge has bottomed out, put
gasoline back into the tank in 16 oz. (one pint) increments until it
just floats. You now know the precise range your gauge can indicate at
the precise angle in flight.
Remove whatever small amounts you added to get back to a "three gallons
down" condition, and carefully measure the remainder of fuel you can
drain. You know it's all useable, because you got it the same way the
engine does (by gravity).
I recommend you calibrate your wing tanks in two steps at different
times. First, fly them dry (so your nose tank gauge is down some
obvious amount and land. Fill the wing tanks four gallons alternately
in each side and top off to about 1/2" below the neck, allowing the
tanks to equalize on level ground. The quantity they took is your
total wing tank capacity. It should be between 16 and 18 gallons.
ASAP, fly the wings dry again. Again, block up the tail as explained
above. Divide your total wing tank capacity by eight. Put this amount
in each wing tank and allow the fuel to even out (side-to-side). Mark
your wing tank fuel gauge "!/4". Repeat, and mark "!/2". Repeat and
mark "3/4". Repeat and mark "Full".
Keep regular records of fuel consumption and tachometer (not Hobbs)
flight hours (not Hobbs), adding an asterisk to cross-country flights.
Use the WORST fuel burn for the previous year on cross-country flights
for flight planning cross country flights. With this information you
can always determine with great accuracy how long you have been in the
air and how much more time you have before starting on your "reserve".
By staying aware of your over-the-ground progress with checkpoints and
a stop watch, you will know with great accuracy when you should reach
your next planned stop; and whether favorable conditions allow you to
extent the leg or adverse conditions demand you shorten it.
Good luck,
William R. Bayne
.____|-(o)-|____.
(Copyright 2010)
--
On Mar 28, 2010, at 19:12, hogowner82 wrote:
Has anyone measured the drop in the header tank fuel gauge stick
versus gallons? If I remember correctly, there's about four gallons
left when the tip of the stick disappears. Personally, I would like to
know how much fuel I have left if the fuel pump quits right down to a
dry tank.
Larry Dixon
N99493
On Mar 28, 2010, at 19:54, Donald wrote:
A similar measurement I would like to have is exactly how much remains
in the wing tanks when the wires touch the cap. Due to the dihedral
approximately 2 gallons are still useable when they show empty. I
know I can fly quite a bit yet until the header tank starts going
down.
