Mailing List lml@lancaironline.net Message #66221
From: Paul Miller <pjdmiller@gmail.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Fuel vol correction
Date: Mon, 22 Jul 2013 09:27:25 -0400
To: <lml@lancaironline.net>
1.   Use the boost to start fuel flow, siphon effect from gascolator will fill a 5g container in about 4 minutes.  That process will completely empty my tanks with nothing left in the sumps on my legacy.  That's a good thing.

2. The fuel probe extends almost to the top of the wing near the fuel cap, you can see it with a mirror.  Top first gallon of fuel consumed is registered on my probe and that is about half an inch from the top.  It is quite accurate full to empty I found.

Paul

On 2013-07-21, at 21:12, "Bill Bradburry" <bbradburry@bellsouth.net> wrote:

> Charles,
>
> I calibrated my gauge by disconnecting my fuel system at the Gascolator and
> using the boost pump to empty the tanks into containers.  I then opened the
> sumps to ensure that they were truly bone dry.  The boost pump removed all
> but a teaspoon or so of fuel.
> My EI fuel gauge reads in eights and shows gallons as well.  So...
> I poured a gallon of fuel in each side and calibrated the gauge to read
> zero.  I poured 4 gallons in and calibrated that to be 1/8 tank and 4
> gallons, another 4 gallons calibrated for 1/4 tank and 8 gallons, etc. until
> I calibrated full to read 32 gallons.  Now the full calibration is not
> accurate because the capacitive sender was inundated with fuel at around 30
> gallons.  That means that I will read full until I get below that level and
> also I should always have a gallon more than is indicated due to my zero
> setting.  I don't see that as much of a problem as I am more interested in
> accuracy at 3/8 tank and below, and I try to always keep the fuel between
> 3/4 and 3/8 full.
> I don't know at what level of fuel you might be able to unport the inlet,
> but I suspect that you could do it with 3-4 gallons in the tank due to the
> way the plane wiggles its tail in turbulence and the low dihedral.
> I prefer not to cause the engine to run funny...it scares the hell out of
> the mouse in my pocket!   :>)
>
> B2
> -----Original Message-----
> From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
> Charles Brown
> Sent: Saturday, July 20, 2013 12:41 PM
> To: lml@lancaironline.net
> Subject: [LML] Re: Fuel vol correction
>
> OK, thanks Bill B, John B, and Bob P for inputs.  Bill's info below is
> interesting in that it confirms that 37 may be a good number if things are
> working right.  I did not sump the tank prior to filling, because I assumed
> I'd put in 37 gallons -- but I may try that next time.  However, it won't
> prove much, will it?  There *should* be *some* fuel left at the sumps,
> regardless; that's where the unusable fuel hangs out, right?
>
> I am the builder, I have photos proving (as I checked at the time) all the
> little half-circle cutouts in the spar were present and not blocked by
> ProSeal; the geometry of the rib caps makes it extremely unlikely that Hysol
> could have blocked the cutouts at wing closing and at any rate, I measured
> the 37gal volume long after the wings were closed.  I can still hear the
> gate valves slapping whenever I rock the airplane on the ground with partial
> fuel, so they're working; and there's no venting issue.  I slipped the plane
> in flight to get the last of the fuel, but maybe not long enough?  Once the
> engine sputters, it could take many seconds to re-establish flow?
> Hmmmm.....
>
> Of course it's possible that some blockage has occurred, I can check that
> out with a borescope, sounds like fun.  Thanks guys, I'll let you know if I
> figure it out.  Good ideas in Bob's article.
>
> CB
>
>
> On Jul 19, 2013, at 2:51 PM, Bill Bradburry wrote:
>
> Charley,
> Did you sump the tank prior to refilling it to ensure that it was truly
> empty?  You may be looking at 3 gallons un-usable.  The Legacy wings have
> little dihedral and there is a lot of sloshing.  You may have unported the
> fuel outlet finger strainer and made you think the tank was empty.
>
> When I calibrated the fuel gage on my Legacy with speed brake wells, both
> tanks were 36 gallons filled to the bottom of the fuel inlet.  37 gallons
> makes sense if you don't have the speed brake wells.
>
> B2
>
> -----Original Message-----
> From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
> Charles Brown
> Sent: Friday, July 19, 2013 7:22 AM
> To: lml@lancaironline.net
> Subject: [LML] Fuel vol correction
>
> I may have provided some bad info in the past.  I stated that the fuel vol
> in my wing tanks was 37 gal per side; attributing the extra to the complete
> absence of speed brake provisions.  However, I just got around to exhausting
> a fuel tank in flight, and refilled it with 34 gallons.  Of the many
> possible variables, the one that seems most dubious is the accuracy of the
> 1/2 gallon measuring cup that was the basis for the original calibration.
> I"m still sorting through this one.
>
> Charley Brown
> Legacy 275 hr
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