Wow. To say you have forgotten more about Ercoupes than most owners know, would be an understatement. Thanks Ed.
Steve On Sep 7, 2010, at 10:59 AM, Ed Burkhead wrote: > > Steve, > > Here's my 2ยข worth: > > (We call the upper tank a "nose" tank or "header" tank. The tanks in the > wings are the "mains" or "wing tanks.") > > I try to always know how much my nose tank was below full. If I've come to > the point in my flight where I'm using fuel from the nose tank, a significant > fraction of my attention is given to the fuel level. > ________________ > > To know how much my nose tank is below full, I calibrated my nose tank gauge. > To do this, I got a good, clean gas can and put a clean funnel and hose > below the gascolator's drain. I drained the nose tank completely. > > Filling the nose tank was done a half gallon at a time. On *MY* plane, at > THAT time, with THAT fuel gauge and cork, it took 3.5 gallons before the wire > gauge came up off the bottom. You *SHOULD* know how much fuel is in the tank > when *YOUR* nose tank float-wire gauge gets to the bottom. > > Filling by half-gallons and marking on rain-proof glass, I calibrated the > gauge up to full. When near full, I waited quite a while between adding any > more so I could determine what the gauge looks like when it's at the full and > drained-down-to-stable level. (When flying, with the fuel pump pumping, the > level will be somewhat above this mark.) > ________________ > > Now, if I've used fuel out of my nose tank in a flight, I know approximately > how much to add to the nose tank. I'll top it off then wait several minutes > so any excess can drain down to the mains. > > Then I fill the mains with the up-hill tank first (if there's any slope at > all) followed quickly by the down-hill tank. Doing it backward could cause > cross-flow resulting in overflow from the down-hill tank. Leave a couple of > inches of airspace below the filler hole to prevent overflow if your plane > gets parked on a slight side-slope or siphoning in flight. Due to the strong > dihedral, that small amount of airspace shouldn't cost you much fuel capacity. > > If you don't have the inside gauge (down below your knee on the cockpit side > wall) then you should have a float gauge on one (or both) of your wing tank > caps. > > Whichever gauge you have on the wing tanks should also be calibrated. > Ideally, I'd do this: > Get a friend to help. Calibrate two pitchers and mark them exactly at the > one-gallon point. (I'm not sure what I'd suggest as an accurate reference > but try to find one rather than just assume some level in a store-bought > product is a gallon.) > > Go fly and empty the mains completely. (Well, you could drain nearly empty > tanks into your clean gas can using the quick drains.) > > Now, fill both pitchers and each of you add that fuel to the main tanks. Put > on your gauge (or check the inside gauge) and record the point at which the > gauge comes off the empty mark. Due to the Coupe's strong dihedral, there's > usually a fair amount of fuel still in the tanks when the float gauge gets to > empty and even when a dipstick used vertically at the filler cap shows empty. > You want to *KNOW* this amount. > > From when the gauge comes off empty, record what the gauge says after you add > each two gallons. > > Over the years, the cork in a float gauge may get saturated with fuel if the > coating was not perfect. This leads to the float being a bit lower an you'll > think your fuel level is lower than it is. That's a fairly safe condition - > to have more fuel than you think you have. But still, I'd re-calibrate every > five years or if I had reason to suspect inaccuracy. > > As a side note, my nose tank float gauge got so saturated that in the middle > of a flight it just sank, suddenly. Talk about pucker factor. Fortunately, > the engine didn't notice the gauge's report and kept running just fine. > After landing, taking the float gauge out of the tank and letting it air in > the sunshine for a couple of hours brought it back to floating for the next > leg of my flight. A couple of days of sunshine and air let it float fine > till I got a replacement. > > I, like many other Coupers, kept the nose tank as a reserve, never planning > to use it on my trips. I think I never used the nose tank but once on any > cross country trip as the mains can hold more fuel than my bladder can hold . > . . > > Six gallons of fuel in the nose tank gives you an hour and a hundred mile > range at max cruise power. With power reduced to maximum range power (about > 5 mph above best glide), your range improves to, maybe, 150 miles. Now > that's comfort! > > One other advantage to all this calibration: Knowing your fuel levels lets > you keep within your desired gross weight when carrying different weights of > passenger and baggage. By knowing the level of fuel in my nose tank and > having the wing tanks empty I was able to take an acquaintance for a 20 > minute local flight even though he weighed as much as I did. > > All the best, > > Ed > Stephen Pizzo http://www.stephen.pizzo.com Step by step we gain'd a freedom known to Europe, known to all; Step by step we rose to greatness,--thro' the tonguesters we may fall. (Tennyson)
