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Miniumum fuel comfort zone

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AirMike

Joined: 27 Feb 2007
Posts: 514
Location: Nevada

Posted: Sat Aug 21, 2010 10:37 pm Post subject: Miniumum fuel comfort zone

In re-analyzing my numbers from my trip to OSH - felt that it is best to be on the ground when you have less than 7 gallons in each tank. I have very accurate readings from my tank floats and fuel scan is right on the money. Since a big percentage of accidents are from just running out of gas, I'd like any input on minimum usable fuel in the std tanks so that we can all keep a comfortable safety zone.



I also need this info as I fit out my 90 gallon internal tank for the round-the-poles flight - ok just kidding.......

_________________
See you OSH '18
Q/B - sold.

jesse(at)saintaviation.co
Guest

Posted: Sun Aug 22, 2010 5:43 am Post subject: Miniumum fuel comfort zone

I think each person probably has their personal limit on this.  Personally, I would much rather have 14 gallons in one tank than 7 gallons in each, maybe unless conditions are perfectly smooth.  Even when flying a 172, on a long trip, I'll burn out of both tanks to verify everything is working in the system, but will burn one tank down until I start losing fuel pressure and then switch so I know all of my fuel is available from the current tank (and it also helps to verify how much fuel I have - see if my calculations are correct, which isn't as much of an issue in the -10).  I do this at altitude so, if there's some kind of hickup, there would be plenty of time to get it worked out.  I don't think I've ever taken the -10 to the point of losing fuel pressure, but I've taken it to the point where the float reads zero and the flow meter agrees.



That's just the way I do it, and I don't like to get on the ground with less than 10 gallons, but all of that on one side if I do get that low.



Jesse Saint

Saint Aviation, Inc.

jesse(at)saintaviation.com

C: 352-427-0285

F: 815-377-3694



On Aug 22, 2010, at 2:37 AM, AirMike wrote:



 	  Quote: 	
		   

 

 In re-analyzing my numbers from my trip to OSH - felt that it is best to be on the ground when you have less than 7 gallons in each tank. I have very accurate readings from my tank floats and fuel scan is right on the money. Since a big percentage of accidents are from just running out of gas, I'd like any input on minimum usable fuel in the std tanks so that we can all keep a comfortable safety zone.


	


 	  Quote: 	
		   I also need this info as I fit out my 90 gallon internal tank for the round-the-poles flight - ok just kidding.......

 

 --------

 OSH '10 or Bust 

 Q/B - finally done

 

 

 do not archive

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=309710#309710

partner14

Joined: 12 Jan 2008
Posts: 540
Location: Granbury Texas

Posted: Sun Aug 22, 2010 7:23 am Post subject: Miniumum fuel comfort zone

Mike, as a new pilot, with a new airplane, one of the first things I thought I should do was run one tank completely out of fuel (while circling the airport).  I did not want to second guess the tank construction (quickbuild).  I also wanted a little confidence increase that the engine would fire right back up after switching tanks.  Of course it did, and after arriving on the ground I was able to drain enough fuel out of the exhausted tank to kill 2 weeds on the taxiway (between 2 to 4 oz).  Then to verify, I fueled up, and it took the entire 30 gallons. (plus a little)   As I think has been reported in a prior post, usable fuel is about 29.8 gallons.  So after the test, on every cross country, I run right down to 29 gallons on both tank......... just kidding!

 But keep in mind, with a lot of the older planes, they only have a mickey mouse fuel gage... where as we have 2 completely independent indicators (actually 3).  Although I suppose all could  fail or be incorrect at the same time, it's doubtful.

 Don McDonald



--- On Sat, 8/21/10, AirMike <Mikeabel(at)Pacbell.net> wrote:



  	  Quote: 	
		  

From: AirMike <Mikeabel(at)Pacbell.net>

Subject: Miniumum fuel comfort zone

To: rv10-list(at)matronics.com

Date: Saturday, August 21, 2010, 11:37 PM



 --> RV10-List message posted by: "AirMike" <Mikeabel(at)Pacbell.net (Mikeabel(at)Pacbell.net)>



In re-analyzing my numbers from my trip to OSH - felt that it is best to be on the ground when you have less than 7 gallons in each tank. I have very accurate readings from my tank floats and fuel scan is right on the money. Since a big percentage of accidents are from just running out of gas, I'd like any input on minimum usable fuel in the std tanks so that we can all keep a comfortable safety zone.



I also need this info as I fit out my 90 gallon internal tank for the round-the-poles flight - ok just kidding.......



--------

OSH '10 or Bust 

Q/B - finally done





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=309710#30971om/Navigator?RV10-List" target=_blank>http://www.matronics.com/Navigator?              - MATRONICS WEB FORUM;               -Matt Dralle, List Admin==========





	


         [quote][b]

_________________
Don A. McDonald
40636

Tim Olson

Joined: 25 Jan 2007
Posts: 2872

Posted: Sun Aug 22, 2010 7:32 am Post subject: Miniumum fuel comfort zone

I go red alarm at 7 gallons on my efis per tank.  I have tested both tanks in flight and all but 1 cup of fuel is useable....so in theory, 1 gallon remaining would be ok.  But I would never fly it that far down unless I have another tank ready. If you aren't in coordinated flight or have to slip or crab on landing, you may need more than that 1 cup remaining.  Also, I tested in level flight.  My float level drops on descent slightly. 1 cup may not be enough on final.  I think the least fuel I've ever landed with is 10 or 12 gallons total. I'm conservative/chicken that way.

Tim



On Aug 22, 2010, at 1:37 AM, "AirMike" <Mikeabel(at)Pacbell.net> wrote:



 	  Quote: 	
		   

 

 In re-analyzing my numbers from my trip to OSH - felt that it is best to be on the ground when you have less than 7 gallons in each tank. I have very accurate readings from my tank floats and fuel scan is right on the money. Since a big percentage of accidents are from just running out of gas, I'd like any input on minimum usable fuel in the std tanks so that we can all keep a comfortable safety zone.

 

 I also need this info as I fit out my 90 gallon internal tank for the round-the-poles flight - ok just kidding.......

 

 --------

 OSH '10 or Bust 

 Q/B - finally done

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=309710#309710

ScooterF15

Joined: 19 Jun 2006
Posts: 136

Posted: Sun Aug 22, 2010 1:05 pm Post subject: Miniumum fuel comfort zone

Before my first flight I disconnected the fuel line at the mechanical fuel pump and put the fuel line in a gas can. I ran the electric fuel pump and pumped both tanks dry (I did this to calibrate my fuel flow transducer). After doing that I was able to drain 5 full strainers out of one tank and 9 strainers out of the other. So for my plane almost all 30 gallons in each tank is useable.

 I have (intentionally) run a tank dry in flight and confirmed this result for my plane.

 However, as a rule, I don't like to see less than 5 gallons in each tank. I always like having the option of switching tanks in the event something plugs the line in use.

 -Jim

 N312JE 

 On Sun, Aug 22, 2010 at 9:32 AM, Tim Olson <Tim(at)myrv10.com (Tim(at)myrv10.com)> wrote:

 [quote]--> RV10-List message posted by: Tim Olson <Tim(at)myrv10.com (Tim(at)myrv10.com)>

I go red alarm at 7 gallons on my efis per tank.  I have tested both tanks in flight and all but 1 cup of fuel is useable....so in theory, 1 gallon remaining would be ok.  But I would never fly it that far down unless I have another tank ready. If you aren't in coordinated flight or have to slip or crab on landing, you may need more than that 1 cup remaining.  Also, I tested in level flight.  My float level drops on descent slightly. 1 cup may not be enough on final.  I think the least fuel I've ever landed with is 10 or 12 gallons total. I'm conservative/chicken that way.

 Tim

On Aug 22, 2010, at 1:37 AM, "AirMike" <Mikeabel(at)Pacbell.net> wrote:

 	  Quote: 	
		   --> RV10-List message posted by: "AirMike" <Mikeabel(at)Pacbell.net>

 > In re-analyzing my numbers from my trip to OSH - felt that it is best to be on the ground when you have less than 7 gallons in each tank. I have very accurate readings from my tank floats and fuel scan is right on the money. Since a big percentage of accidents are from just running out of gas, I'd like any input on minimum usable fuel in the std tanks so that we can all keep a comfortable safety zone.

 >

 	  Quote: 	
		   I also need this info as I fit out my 90 gallon internal tank for the round-the-poles flight - ok just kidding.......

 --------

 OSH '10 or Bust

 Q/B - finally done

 >

 	  Quote: 	

 Read this topic online here:

 	  Quote: 	
		   http://forums.matronics.com/viewtopic.php?p=309710#309710

 >

 	  Quote: 	

&atures Navigator to browse

 s.com/Navigator?RV10-List" target="_blank">http://www.matronics.com/Navigator?RV10-List

 ronics.com/" target="_blank">http://forums.matronics.com

 Matt Dralle, List Admin.

 =====

[b]

Tim Olson

Joined: 25 Jan 2007
Posts: 2872

Posted: Sun Aug 22, 2010 6:34 pm Post subject: Miniumum fuel comfort zone

You know, I somewhat feel the same regarding fuel, that

I like to burn a lot off one tank and then I know if my

other tank is plenty full I'm doing great, but...I don't

know that I'd take it quite as far as you do with it.

I agree with Jim, I think 5 gallons remaining is a good

bottom limit for most of the time.  Here's why...



First, if you run a tank to the very end, you're going

to have a little more chance to get all the gunk

and water that may be at that low spot in the tank.

Granted that since our inlet is obviously REALLY close

to the low spot, it probably doesn't matter much, but

just in concept, I don't know that bottom feeding

on the tank is such a great normal routine.



Second, at least on my EFIS I have each tank set to

alarm below a certain point.  If I flew one to

empty as a routine, I'd have to silence an alarm,

and I don't want to get in the habit of routinely

silencing something like that if I can avoid it.



Third, like Jim mentioned, it's nice to have

a few gallons in that tank that you just don't

use, because those can be used to fall back on

later.  What if suddenly your 2nd and final

tank swallows a gob of water that won't run through

and your engine dies?  If you have even a couple gallons

available, you can make it quite a few more miles

to get to an airport.  I'd always leave 5 gallons

just so you have an "out".



And last, I did a write up once, but on one IFR flight

in IMC, I noticed my tank was using fuel faster than

normal.  Stupid me, I switched to the OTHER tank,

well...it wasn't stupid exactly, but that helped me

identify that indeed with the tank shut off I was

draining fuel still.  But what I SHOULD have done is

after verifying, switched back to that tank and

used it up...rather than waste all that fuel.  I had

sumped the tanks in the rain and with all the rain

coming down, didn't notice the sump was still dripping

and wasn't sealed well.  If I would have been using

my opposite tank, and I used it to empty, I could

have put myself into a situation where I had one

empty tank and a problem (leak) with the other.



Anyway, not really wanting to nit pick on a procedure,

since everyone can have their own, but I thought I'd

point out a couple of things on it as to why it's probably

best to keep a few gallons in there.



I do know what you mean though. I know people that

religiously switch tanks every 30 minutes. That's

fine, no problem there, but I myself would rather

maybe burn the top 10 gallons off one tank,

then suck 23 gallons out of the 2nd tank,

and then burn my last 13 gallons off the

original tank.  Less switching, and like you,

I like to burn a pile of my fuel off and then have

a good amount in my final tank so I can easily

figure that I'll make my home stretch without

needing to swap back to that lower tank again.



Tim Olson - RV-10 N104CD

do not archive

On 8/22/2010 8:33 AM, Jesse Saint wrote:

 	  Quote: 	
		   

 Saint<jesse(at)saintaviation.com>



 I think each person probably has their personal limit on this.

 Personally, I would much rather have 14 gallons in one tank than 7

 gallons in each, maybe unless conditions are perfectly smooth.  Even

 when flying a 172, on a long trip, I'll burn out of both tanks to

 verify everything is working in the system, but will burn one tank

 down until I start losing fuel pressure and then switch so I know all

 of my fuel is available from the current tank (and it also helps to

 verify how much fuel I have - see if my calculations are correct,

 which isn't as much of an issue in the -10).  I do this at altitude

 so, if there's some kind of hickup, there would be plenty of time to

 get it worked out.  I don't think I've ever taken the -10 to the

 point of losing fuel pressure, but I've taken it to the point where

 the float reads zero and the flow meter agrees.



 That's just the way I do it, and I don't like to get on the ground

 with less than 10 gallons, but all of that on one side if I do get

 that low.



 Jesse Saint Saint Aviation, Inc. jesse(at)saintaviation.com C:

 352-427-0285 F: 815-377-3694



 On Aug 22, 2010, at 2:37 AM, AirMike wrote:



> 

>

> In re-analyzing my numbers from my trip to OSH - felt that it is

> best to be on the ground when you have less than 7 gallons in each

> tank. I have very accurate readings from my tank floats and fuel

> scan is right on the money. Since a big percentage of accidents are

> from just running out of gas, I'd like any input on minimum usable

> fuel in the std tanks so that we can all keep a comfortable safety

> zone.



> I also need this info as I fit out my 90 gallon internal tank for

> the round-the-poles flight - ok just kidding.......

>

> -------- OSH '10 or Bust Q/B - finally done

> do not archive

>

> Read this topic online here:

>

> http://forums.matronics.com/viewtopic.php?p=309710#309710

>

>

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Sun Aug 22, 2010 6:43 pm Post subject: Miniumum fuel comfort zone

Tim, I agree with all but the concept of gunk at the bottom of the 

tank only getting pulled into the system as the tank goes dry. The 

maximum flow out of the tank is at full power when you are using that 

tank and are nose high. In other words the max flow to dislodge anything 

at the bottom is on departure, not in cruise or descent. If something 

sticks enough to still be there as you empty that tank, it isn't going 

anywhere with the last gallon of fuel. I think you realize this, but it 

is a hard image to dismiss.

Kelly

On 8/22/2010 7:28 PM, Tim Olson wrote:

 	  Quote: 	
		   



 You know, I somewhat feel the same regarding fuel,

 First, if you run a tank to the very end, you're going

 to have a little more chance to get all the gunk

 and water that may be at that low spot in the tank.

 Granted that since our inlet is obviously REALLY close

 to the low spot, it probably doesn't matter much, but

 just in concept, I don't know that bottom feeding

 on the tank is such a great normal routine.

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

jesse(at)saintaviation.co
Guest

Posted: Sun Aug 22, 2010 7:34 pm Post subject: Miniumum fuel comfort zone

I think the issue is more of a minimum fuel & where to have it.  In normal practice, I burn down 10-15 on one side, switch & burn down to 10 on the other, then switch.  Only on a long trip where I may be down to reserve do I do as I suggested.  I personally think making minimum fuel of 7 per side too much.  That's 46 gal useable.  If it's a trip that would need 92 gallons, I would split it in half.  If it's a 52-gallon flight, I would not split it up.  Then I would burn down one tank dry or almost so, then fly my last stretch only on the other.  I would much rather be flying with 8 gallons in one tank than 4 gallons in each.  I think that's the issue.  

I agree that fuel alarms are good and important, but they are there to remind you in case you forget.  On a long flight (like my nonstop from FL to WI for OSH), my main task is to let my autopilot fly the plane while I monitor my fuel, using the fuel computer & winds aloft info along my route to estimate fuel at destination.  I then decide how close to minimum fuel I will be flying & burn accordingly.  On a flight like that, the last thing I need is a low fuel alarm.  Also, I have noticed with several systems that if I set an alarm at 5 gallons, I need to keep the tank well above that or well below it to not have the alarm constantly going off as the float bounces when the fuel sloshes.  Once down to 2-3 gallons, a 5-gal alarm will seldom go off after the first time.  Once acknowledged & noted on the kneeboard, it's known & that tank not used again.

Another thing I do is switch to the full tank one or twice for a minute or two before I go "dry" on one side to verify fuel supply is good & no flow restrictions.

As you said, everybody will have their own way.  This is the way that makes me feel the most comfortable.

Jesse Saint

I-TEC, Inc.

jesse(at)itecusa.org

www.itecusa.org

www.mavericklsa.com

C: 352-427-0285

O: 352-465-4545

F: 815-377-3694

Sent from my iPhone

On Aug 22, 2010, at 10:28 PM, Tim Olson <Tim(at)myrv10.com> wrote:

 	  Quote: 	

 You know, I somewhat feel the same regarding fuel, that

 I like to burn a lot off one tank and then I know if my

 other tank is plenty full I'm doing great, but...I don't

 know that I'd take it quite as far as you do with it.

 I agree with Jim, I think 5 gallons remaining is a good

 bottom limit for most of the time.  Here's why...

 First, if you run a tank to the very end, you're going

 to have a little more chance to get all the gunk

 and water that may be at that low spot in the tank.

 Granted that since our inlet is obviously REALLY close

 to the low spot, it probably doesn't matter much, but

 just in concept, I don't know that bottom feeding

 on the tank is such a great normal routine.

 Second, at least on my EFIS I have each tank set to

 alarm below a certain point.  If I flew one to

 empty as a routine, I'd have to silence an alarm,

 and I don't want to get in the habit of routinely

 silencing something like that if I can avoid it.

 Third, like Jim mentioned, it's nice to have

 a few gallons in that tank that you just don't

 use, because those can be used to fall back on

 later.  What if suddenly your 2nd and final

 tank swallows a gob of water that won't run through

 and your engine dies?  If you have even a couple gallons

 available, you can make it quite a few more miles

 to get to an airport.  I'd always leave 5 gallons

 just so you have an "out".

 And last, I did a write up once, but on one IFR flight

 in IMC, I noticed my tank was using fuel faster than

 normal.  Stupid me, I switched to the OTHER tank,

 well...it wasn't stupid exactly, but that helped me

 identify that indeed with the tank shut off I was

 draining fuel still.  But what I SHOULD have done is

 after verifying, switched back to that tank and

 used it up...rather than waste all that fuel.  I had

 sumped the tanks in the rain and with all the rain

 coming down, didn't notice the sump was still dripping

 and wasn't sealed well.  If I would have been using

 my opposite tank, and I used it to empty, I could

 have put myself into a situation where I had one

 empty tank and a problem (leak) with the other.

 Anyway, not really wanting to nit pick on a procedure,

 since everyone can have their own, but I thought I'd

 point out a couple of things on it as to why it's probably

 best to keep a few gallons in there.

 I do know what you mean though. I know people that

 religiously switch tanks every 30 minutes. That's

 fine, no problem there, but I myself would rather

 maybe burn the top 10 gallons off one tank,

 then suck 23 gallons out of the 2nd tank,

 and then burn my last 13 gallons off the

 original tank.  Less switching, and like you,

 I like to burn a pile of my fuel off and then have

 a good amount in my final tank so I can easily

 figure that I'll make my home stretch without

 needing to swap back to that lower tank again.

 Tim Olson - RV-10 N104CD

 do not archive

 On 8/22/2010 8:33 AM, Jesse Saint wrote:

> 

> Saint<jesse(at)saintaviation.com>

> 

> I think each person probably has their personal limit on this.

> Personally, I would much rather have 14 gallons in one tank than 7

> gallons in each, maybe unless conditions are perfectly smooth.  Even

> when flying a 172, on a long trip, I'll burn out of both tanks to

> verify everything is working in the system, but will burn one tank

> down until I start losing fuel pressure and then switch so I know all

> of my fuel is available from the current tank (and it also helps to

> verify how much fuel I have - see if my calculations are correct,

> which isn't as much of an issue in the -10).  I do this at altitude

> so, if there's some kind of hickup, there would be plenty of time to

> get it worked out.  I don't think I've ever taken the -10 to the

> point of losing fuel pressure, but I've taken it to the point where

> the float reads zero and the flow meter agrees.

> 

> That's just the way I do it, and I don't like to get on the ground

> with less than 10 gallons, but all of that on one side if I do get

> that low.

> 

> Jesse Saint Saint Aviation, Inc. jesse(at)saintaviation.com C:

> 352-427-0285 F: 815-377-3694

> 

> On Aug 22, 2010, at 2:37 AM, AirMike wrote:

> 

>> 

>> 

>> In re-analyzing my numbers from my trip to OSH - felt that it is

>> best to be on the ground when you have less than 7 gallons in each

>> tank. I have very accurate readings from my tank floats and fuel

>> scan is right on the money. Since a big percentage of accidents are

>> from just running out of gas, I'd like any input on minimum usable

>> fuel in the std tanks so that we can all keep a comfortable safety

>> zone.

> 

>> I also need this info as I fit out my 90 gallon internal tank for

>> the round-the-poles flight - ok just kidding.......

>> 

>> -------- OSH '10 or Bust Q/B - finally done

>> 

>> 

>> do not archive

>> 

>> Read this topic online here:

>> 

>> http://forums.matronics.com/viewtopic.php?p=309710#309710

>> 

>> 

>> 

>> 

>> 

>> 

>> 

>> 

>> 

>> 

> 

> 

> 

> 

> 

>

dlm46007(at)cox.net
Guest

Posted: Sun Aug 22, 2010 8:01 pm Post subject: Miniumum fuel comfort zone

Just to give some idea of accuracy, my GRT EIS/  Chelton setup provides accuracies of one or two tenths of a  gallon. I would consider using into the last 10 gallons provided my destination  was less than 50 miles, had multiple runways and conditions were "golden"  VFR. 

  

 Also addressing Tim's "gunk" in the tanks; Most  junk in he tanks I have found in the tanks was left there by the builders. My QB  tanks had bits of proseal when I flushed them. In 35 years of flying, I have  found water twice and each time it was attributable to a FBO pumping the water  in; 

  

 One from a tank truck at OSH and once from a FBO  pumping it in from an underground tank. The OSH incident was discovered on the  ground and quantities were copious; The engine would have surely quit before  getting airborne as there were several quarts each side. 

  

 The RVS incident was discovered climbing through  5000; the tanks were slumped prior to filling and the water was thoroughly  mixed. I eliminated the water at FSM.

  

  

 ---

Tim Olson

Joined: 25 Jan 2007
Posts: 2872

Posted: Mon Aug 23, 2010 5:34 am Post subject: Miniumum fuel comfort zone

"I would much rather be flying with 8 gallons in one tank than

  4 gallons in each.  I think that's the issue."



I kind of agree with that statement, mainly from the standpoint

of fuel unporting during landing.  I don't know that the best

balance would be 8/0 as opposed to 4/4, but I agree with your

point.  Actually, when I do land with less fuel, it's usually

7/5 or something of that nature, so in theory I agree...I only

want one tank to be near the bottom.  Our comfort with "bottom"

is just a little different.  With the totalizers and the high

accuracy we have though, it's probably practical to be able

to go 6/2 on that split that you mention...that way there's

enough to finish a landing if needed, with bare minimum fuel,

but still plan to finish the flight with 6 gallons in the

active tank.



I probably, considering the accuracy of my totalizer, take

conservative fuel planning a little far in that I don't think

I've ever landed with less than 10 gallons in the RV-10,

but I suppose if you're going to err, the high side is

probably good.  Not that what you're doing is an err. 

There are more airports in your neck of the woods than mine,

too, to use as alternates.  And, I feel MUCH better about

cutting fuel close on my trip to my home airport than

I do when I'm landing at somewhere unfamiliar.  I know

how quick I can get on the ground at my home base.



The one point I made about useable fuel though that I think

is real important is the one about tank angle and useable

fuel.  I know my floats drop maybe 2-3 gallons or so when I

transition from cruise to descent with lower fuel levels.

I think it would be a good test if someone burned a tank down

to, say 4 gallons, and then did a series of climbs to

10,000 AGL and switched to that tank and did a descent,

and waited for the fuel to run out.  It may take a while to

burn 4 gallons at descent power, but some day one of us

should find out what minimum fuel is at descent angle.

Knowing where the fuel pickup is, I can see that perhaps

minimum fuel may be a gallon or as much as 2 gallons,

depending on the angle.  I could be wrong.  Many of

us have tested it in level flight though with the same

results....so I'd assume that one good test in descent

would let us know.



Regardless of fuel management procedure, what's important is

that people have a procedure and plan that works for them.

It would be nice to be able to look back in a few years and

say "in the last 10 years, never has an RV-10 been lost to

fuel exhaustion".  It's one of those things that just shouldn't

happen to people unless they do something stupid.



Tim Olson - RV-10 N104CD



On 8/22/2010 10:23 PM, Jesse Saint wrote:

 	  Quote: 	
		   

 Saint<jesse(at)saintaviation.com>



 I think the issue is more of a minimum fuel&  where to have it.  In

 normal practice, I burn down 10-15 on one side, switch&  burn down to

 10 on the other, then switch.  Only on a long trip where I may be

 down to reserve do I do as I suggested.  I personally think making

 minimum fuel of 7 per side too much.  That's 46 gal useable.  If it's

 a trip that would need 92 gallons, I would split it in half.  If it's

 a 52-gallon flight, I would not split it up.  Then I would burn down

 one tank dry or almost so, then fly my last stretch only on the

 other.  I would much rather be flying with 8 gallons in one tank than

 4 gallons in each.  I think that's the issue.



 I agree that fuel alarms are good and important, but they are there

 to remind you in case you forget.  On a long flight (like my nonstop

 from FL to WI for OSH), my main task is to let my autopilot fly the

 plane while I monitor my fuel, using the fuel computer&  winds aloft

 info along my route to estimate fuel at destination.  I then decide

 how close to minimum fuel I will be flying&  burn accordingly.  On a

 flight like that, the last thing I need is a low fuel alarm.  Also, I

 have noticed with several systems that if I set an alarm at 5

 gallons, I need to keep the tank well above that or well below it to

 not have the alarm constantly going off as the float bounces when the

 fuel sloshes.  Once down to 2-3 gallons, a 5-gal alarm will seldom go

 off after the first time.  Once acknowledged&  noted on the

 kneeboard, it's known&  that tank not used again.



 Another thing I do is switch to the full tank one or twice for a

 minute or two before I go "dry" on one side to verify fuel supply is

 good&  no flow restrictions.



 As you said, everybody will have their own way.  This is the way that

 makes me feel the most comfortable.



 Jesse Saint I-TEC, Inc. jesse(at)itecusa.org www.itecusa.org

 www.mavericklsa.com C: 352-427-0285 O: 352-465-4545 F: 815-377-3694



 Sent from my iPhone



 On Aug 22, 2010, at 10:28 PM, Tim Olson<Tim(at)myrv10.com>  wrote:



> 

>

> You know, I somewhat feel the same regarding fuel, that I like to

> burn a lot off one tank and then I know if my other tank is plenty

> full I'm doing great, but...I don't know that I'd take it quite as

> far as you do with it. I agree with Jim, I think 5 gallons

> remaining is a good bottom limit for most of the time.  Here's

> why...

>

> First, if you run a tank to the very end, you're going to have a

> little more chance to get all the gunk and water that may be at

> that low spot in the tank. Granted that since our inlet is

> obviously REALLY close to the low spot, it probably doesn't matter

> much, but just in concept, I don't know that bottom feeding on the

> tank is such a great normal routine.

>

> Second, at least on my EFIS I have each tank set to alarm below a

> certain point.  If I flew one to empty as a routine, I'd have to

> silence an alarm, and I don't want to get in the habit of

> routinely silencing something like that if I can avoid it.

>

> Third, like Jim mentioned, it's nice to have a few gallons in that

> tank that you just don't use, because those can be used to fall

> back on later.  What if suddenly your 2nd and final tank swallows a

> gob of water that won't run through and your engine dies?  If you

> have even a couple gallons available, you can make it quite a few

> more miles to get to an airport.  I'd always leave 5 gallons just

> so you have an "out".

>

> And last, I did a write up once, but on one IFR flight in IMC, I

> noticed my tank was using fuel faster than normal.  Stupid me, I

> switched to the OTHER tank, well...it wasn't stupid exactly, but

> that helped me identify that indeed with the tank shut off I was

> draining fuel still.  But what I SHOULD have done is after

> verifying, switched back to that tank and used it up...rather than

> waste all that fuel.  I had sumped the tanks in the rain and with

> all the rain coming down, didn't notice the sump was still

> dripping and wasn't sealed well.  If I would have been using my

> opposite tank, and I used it to empty, I could have put myself into

> a situation where I had one empty tank and a problem (leak) with

> the other.

>

> Anyway, not really wanting to nit pick on a procedure, since

> everyone can have their own, but I thought I'd point out a couple

> of things on it as to why it's probably best to keep a few gallons

> in there.

>

> I do know what you mean though. I know people that religiously

> switch tanks every 30 minutes. That's fine, no problem there, but I

> myself would rather maybe burn the top 10 gallons off one tank,

> then suck 23 gallons out of the 2nd tank, and then burn my last 13

> gallons off the original tank.  Less switching, and like you, I

> like to burn a pile of my fuel off and then have a good amount in

> my final tank so I can easily figure that I'll make my home stretch

> without needing to swap back to that lower tank again.

>

> Tim Olson - RV-10 N104CD do not archive

> On 8/22/2010 8:33 AM, Jesse Saint wrote:

>> 

>> Saint<jesse(at)saintaviation.com>

>>

>> I think each person probably has their personal limit on this.

>> Personally, I would much rather have 14 gallons in one tank than

>> 7 gallons in each, maybe unless conditions are perfectly smooth.

>> Even when flying a 172, on a long trip, I'll burn out of both

>> tanks to verify everything is working in the system, but will

>> burn one tank down until I start losing fuel pressure and then

>> switch so I know all of my fuel is available from the current

>> tank (and it also helps to verify how much fuel I have - see if

>> my calculations are correct, which isn't as much of an issue in

>> the -10).  I do this at altitude so, if there's some kind of

>> hickup, there would be plenty of time to get it worked out.  I

>> don't think I've ever taken the -10 to the point of losing fuel

>> pressure, but I've taken it to the point where the float reads

>> zero and the flow meter agrees.

>>

>> That's just the way I do it, and I don't like to get on the

>> ground with less than 10 gallons, but all of that on one side if

>> I do get that low.

>>

>> Jesse Saint Saint Aviation, Inc. jesse(at)saintaviation.com C:

>> 352-427-0285 F: 815-377-3694

>>

>> On Aug 22, 2010, at 2:37 AM, AirMike wrote:

>>

>>> 

>>> "AirMike"<Mikeabel(at)Pacbell.net>

>>>

>>> In re-analyzing my numbers from my trip to OSH - felt that it

>>> is best to be on the ground when you have less than 7 gallons

>>> in each tank. I have very accurate readings from my tank floats

>>> and fuel scan is right on the money. Since a big percentage of

>>> accidents are from just running out of gas, I'd like any input

>>> on minimum usable fuel in the std tanks so that we can all keep

>>> a comfortable safety zone.

>>

>>> I also need this info as I fit out my 90 gallon internal tank

>>> for the round-the-poles flight - ok just kidding.......

>>>

>>> -------- OSH '10 or Bust Q/B - finally done

>>>

>>>

>>> do not archive

>>>

>>> Read this topic online here:

>>>

>>> http://forums.matronics.com/viewtopic.php?p=309710#309710

>>>

>>>

>>>

>>>

>>>

>>>

>>>

>>>

>>>

>>>

>>

>>

>>

>>

>>

>>

>

>

jesse(at)saintaviation.co
Guest

Posted: Mon Aug 23, 2010 8:35 am Post subject: Miniumum fuel comfort zone

I agree that it would be great to have someone test the descent angle with low fuel.  However, if it does prove to unport at 2 gallons, then my 8/0 would be much better than 6/2, because I would have access to 6 gallons instead of 4, and much less chance of unporting in rough air, especially if I can trim or hold rudder a little bit to keep the fueled side high.  As you said, the most important thing is that people have a system that works for them and that they are comfortable with.  For me, it's having all of my fuel in the active tank.  For others it may be having access to both tanks.



On the water issue, does everybody smell their fuel after they sump to verify that it isn't all water?  I have heard of cases where someone sumped, didn't see the "bubble" of water, and went on their way, not realizing that the whole sump was full of water, not fuel.  I always smell it.  Is that an accurate way of determining that it's fuel, or does water that has been in the fuel tank also smell like fuel in the cup?



Jesse Saint

Saint Aviation, Inc.

jesse(at)saintaviation.com

C: 352-427-0285

F: 815-377-3694



On Aug 23, 2010, at 9:32 AM, Tim Olson wrote:



 	  Quote: 	
		   

 

 "I would much rather be flying with 8 gallons in one tank than

 4 gallons in each.  I think that's the issue."

 

 I kind of agree with that statement, mainly from the standpoint

 of fuel unporting during landing.  I don't know that the best

 balance would be 8/0 as opposed to 4/4, but I agree with your

 point.  Actually, when I do land with less fuel, it's usually

 7/5 or something of that nature, so in theory I agree...I only

 want one tank to be near the bottom.  Our comfort with "bottom"

 is just a little different.  With the totalizers and the high

 accuracy we have though, it's probably practical to be able

 to go 6/2 on that split that you mention...that way there's

 enough to finish a landing if needed, with bare minimum fuel,

 but still plan to finish the flight with 6 gallons in the

 active tank.

 

 I probably, considering the accuracy of my totalizer, take

 conservative fuel planning a little far in that I don't think

 I've ever landed with less than 10 gallons in the RV-10,

 but I suppose if you're going to err, the high side is

 probably good.  Not that what you're doing is an err. 

 There are more airports in your neck of the woods than mine,

 too, to use as alternates.  And, I feel MUCH better about

 cutting fuel close on my trip to my home airport than

 I do when I'm landing at somewhere unfamiliar.  I know

 how quick I can get on the ground at my home base.

 

 The one point I made about useable fuel though that I think

 is real important is the one about tank angle and useable

 fuel.  I know my floats drop maybe 2-3 gallons or so when I

 transition from cruise to descent with lower fuel levels.

 I think it would be a good test if someone burned a tank down

 to, say 4 gallons, and then did a series of climbs to

 10,000 AGL and switched to that tank and did a descent,

 and waited for the fuel to run out.  It may take a while to

 burn 4 gallons at descent power, but some day one of us

 should find out what minimum fuel is at descent angle.

 Knowing where the fuel pickup is, I can see that perhaps

 minimum fuel may be a gallon or as much as 2 gallons,

 depending on the angle.  I could be wrong.  Many of

 us have tested it in level flight though with the same

 results....so I'd assume that one good test in descent

 would let us know.

 

 Regardless of fuel management procedure, what's important is

 that people have a procedure and plan that works for them.

 It would be nice to be able to look back in a few years and

 say "in the last 10 years, never has an RV-10 been lost to

 fuel exhaustion".  It's one of those things that just shouldn't

 happen to people unless they do something stupid.

 

 Tim Olson - RV-10 N104CD

 

 

 

 On 8/22/2010 10:23 PM, Jesse Saint wrote:

> 

> Saint<jesse(at)saintaviation.com>

> 

> I think the issue is more of a minimum fuel&  where to have it.  In

> normal practice, I burn down 10-15 on one side, switch&  burn down to

> 10 on the other, then switch.  Only on a long trip where I may be

> down to reserve do I do as I suggested.  I personally think making

> minimum fuel of 7 per side too much.  That's 46 gal useable.  If it's

> a trip that would need 92 gallons, I would split it in half.  If it's

> a 52-gallon flight, I would not split it up.  Then I would burn down

> one tank dry or almost so, then fly my last stretch only on the

> other.  I would much rather be flying with 8 gallons in one tank than

> 4 gallons in each.  I think that's the issue.

> 

> I agree that fuel alarms are good and important, but they are there

> to remind you in case you forget.  On a long flight (like my nonstop

> from FL to WI for OSH), my main task is to let my autopilot fly the

> plane while I monitor my fuel, using the fuel computer&  winds aloft

> info along my route to estimate fuel at destination.  I then decide

> how close to minimum fuel I will be flying&  burn accordingly.  On a

> flight like that, the last thing I need is a low fuel alarm.  Also, I

> have noticed with several systems that if I set an alarm at 5

> gallons, I need to keep the tank well above that or well below it to

> not have the alarm constantly going off as the float bounces when the

> fuel sloshes.  Once down to 2-3 gallons, a 5-gal alarm will seldom go

> off after the first time.  Once acknowledged&  noted on the

> kneeboard, it's known&  that tank not used again.

> 

> Another thing I do is switch to the full tank one or twice for a

> minute or two before I go "dry" on one side to verify fuel supply is

> good&  no flow restrictions.

> 

> As you said, everybody will have their own way.  This is the way that

> makes me feel the most comfortable.

> 

> Jesse Saint I-TEC, Inc. jesse(at)itecusa.org www.itecusa.org

> www.mavericklsa.com C: 352-427-0285 O: 352-465-4545 F: 815-377-3694

> 

> Sent from my iPhone

> 

> On Aug 22, 2010, at 10:28 PM, Tim Olson<Tim(at)myrv10.com>  wrote:

> 

>> 

>> 

>> You know, I somewhat feel the same regarding fuel, that I like to

>> burn a lot off one tank and then I know if my other tank is plenty

>> full I'm doing great, but...I don't know that I'd take it quite as

>> far as you do with it. I agree with Jim, I think 5 gallons

>> remaining is a good bottom limit for most of the time.  Here's

>> why...

>> 

>> First, if you run a tank to the very end, you're going to have a

>> little more chance to get all the gunk and water that may be at

>> that low spot in the tank. Granted that since our inlet is

>> obviously REALLY close to the low spot, it probably doesn't matter

>> much, but just in concept, I don't know that bottom feeding on the

>> tank is such a great normal routine.

>> 

>> Second, at least on my EFIS I have each tank set to alarm below a

>> certain point.  If I flew one to empty as a routine, I'd have to

>> silence an alarm, and I don't want to get in the habit of

>> routinely silencing something like that if I can avoid it.

>> 

>> Third, like Jim mentioned, it's nice to have a few gallons in that

>> tank that you just don't use, because those can be used to fall

>> back on later.  What if suddenly your 2nd and final tank swallows a

>> gob of water that won't run through and your engine dies?  If you

>> have even a couple gallons available, you can make it quite a few

>> more miles to get to an airport.  I'd always leave 5 gallons just

>> so you have an "out".

>> 

>> And last, I did a write up once, but on one IFR flight in IMC, I

>> noticed my tank was using fuel faster than normal.  Stupid me, I

>> switched to the OTHER tank, well...it wasn't stupid exactly, but

>> that helped me identify that indeed with the tank shut off I was

>> draining fuel still.  But what I SHOULD have done is after

>> verifying, switched back to that tank and used it up...rather than

>> waste all that fuel.  I had sumped the tanks in the rain and with

>> all the rain coming down, didn't notice the sump was still

>> dripping and wasn't sealed well.  If I would have been using my

>> opposite tank, and I used it to empty, I could have put myself into

>> a situation where I had one empty tank and a problem (leak) with

>> the other.

>> 

>> Anyway, not really wanting to nit pick on a procedure, since

>> everyone can have their own, but I thought I'd point out a couple

>> of things on it as to why it's probably best to keep a few gallons

>> in there.

>> 

>> I do know what you mean though. I know people that religiously

>> switch tanks every 30 minutes. That's fine, no problem there, but I

>> myself would rather maybe burn the top 10 gallons off one tank,

>> then suck 23 gallons out of the 2nd tank, and then burn my last 13

>> gallons off the original tank.  Less switching, and like you, I

>> like to burn a pile of my fuel off and then have a good amount in

>> my final tank so I can easily figure that I'll make my home stretch

>> without needing to swap back to that lower tank again.

>> 

>> Tim Olson - RV-10 N104CD do not archive

>> 

>> 

>> On 8/22/2010 8:33 AM, Jesse Saint wrote:

>>> 

>>> Saint<jesse(at)saintaviation.com>

>>> 

>>> I think each person probably has their personal limit on this.

>>> Personally, I would much rather have 14 gallons in one tank than

>>> 7 gallons in each, maybe unless conditions are perfectly smooth.

>>> Even when flying a 172, on a long trip, I'll burn out of both

>>> tanks to verify everything is working in the system, but will

>>> burn one tank down until I start losing fuel pressure and then

>>> switch so I know all of my fuel is available from the current

>>> tank (and it also helps to verify how much fuel I have - see if

>>> my calculations are correct, which isn't as much of an issue in

>>> the -10).  I do this at altitude so, if there's some kind of

>>> hickup, there would be plenty of time to get it worked out.  I

>>> don't think I've ever taken the -10 to the point of losing fuel

>>> pressure, but I've taken it to the point where the float reads

>>> zero and the flow meter agrees.

>>> 

>>> That's just the way I do it, and I don't like to get on the

>>> ground with less than 10 gallons, but all of that on one side if

>>> I do get that low.

>>> 

>>> Jesse Saint Saint Aviation, Inc. jesse(at)saintaviation.com C:

>>> 352-427-0285 F: 815-377-3694

>>> 

>>> On Aug 22, 2010, at 2:37 AM, AirMike wrote:

>>> 

>>>> 

>>>> "AirMike"<Mikeabel(at)Pacbell.net>

>>>> 

>>>> In re-analyzing my numbers from my trip to OSH - felt that it

>>>> is best to be on the ground when you have less than 7 gallons

>>>> in each tank. I have very accurate readings from my tank floats

>>>> and fuel scan is right on the money. Since a big percentage of

>>>> accidents are from just running out of gas, I'd like any input

>>>> on minimum usable fuel in the std tanks so that we can all keep

>>>> a comfortable safety zone.

>>> 

>>>> I also need this info as I fit out my 90 gallon internal tank

>>>> for the round-the-poles flight - ok just kidding.......

>>>> 

>>>> -------- OSH '10 or Bust Q/B - finally done

>>>> 

>>>> 

>>>> do not archive

>>>> 

>>>> Read this topic online here:

>>>> 

>>>> http://forums.matronics.com/viewtopic.php?p=309710#309710

>>>> 

>>>> 

>>>> 

>>>> 

>>>> 

>>>> 

>>>> 

>>>> 

>>>> 

>>>> 

>>> 

>>> 

>>> 

>>> 

>>> 

>>> 

>> 

>> 

>> 

>> 

> 

> 

> 

> 

>

Tim Olson

Joined: 25 Jan 2007
Posts: 2872

Posted: Mon Aug 23, 2010 8:55 am Post subject: Miniumum fuel comfort zone

You're right on that, which is why I like having one fuller

tank like you do.  That's why I've used 7 as a yellow

caution and 5 as a red on my float levels....it keeps

me well above any unporting that should happen for normal

flight.  But you're right, if I were stretching my

reserves to the minimum, I'd rather have plenty in

one tank so that unporting wasn't an issue.



The Sundowner I used to fly, I think was placarded to

no takeoffs with less than 11 gallons in a tank (if I

remember right) solely because of the unporting issue.

I figured if that tank can unport at 11 gallons,

and I didn't have any data on the RV-10 unporting,

I should either test it or keep enough in there

that I'm comfortable with it based on useable fuel.

I think that plane had like 2 gallons unusable though,

too, so it wasn't an apples to apples comparison.



I do smell the fuel, myself. I also if I have reason

to suspect water, feel the fuel between my fingers

and smell them too.  You can tell if it's fuel

or water that way.  I've rarely had water in the

RV-10 tanks though, except when outside in the

rain BEFORE I lubed and cleaned my fuel cap

orings (both of them).  I used to get fuel leakage

on climbout from the stem oring, and that stem also

let in water during rain.  Now though, it doesn't

do that anymore...and I haven't had water since.



Tim Olson - RV-10 N104CD

do not archive

On 8/23/2010 11:28 AM, Jesse Saint wrote:

 	  Quote: 	
		   

 Saint<jesse(at)saintaviation.com>



 I agree that it would be great to have someone test the descent angle

 with low fuel.  However, if it does prove to unport at 2 gallons,

 then my 8/0 would be much better than 6/2, because I would have

 access to 6 gallons instead of 4, and much less chance of unporting

 in rough air, especially if I can trim or hold rudder a little bit to

 keep the fueled side high.  As you said, the most important thing is

 that people have a system that works for them and that they are

 comfortable with.  For me, it's having all of my fuel in the active

 tank.  For others it may be having access to both tanks.



 On the water issue, does everybody smell their fuel after they sump

 to verify that it isn't all water?  I have heard of cases where

 someone sumped, didn't see the "bubble" of water, and went on their

 way, not realizing that the whole sump was full of water, not fuel.

 I always smell it.  Is that an accurate way of determining that it's

 fuel, or does water that has been in the fuel tank also smell like

 fuel in the cup?



 Jesse Saint Saint Aviation, Inc. jesse(at)saintaviation.com C:

 352-427-0285 F: 815-377-3694



 On Aug 23, 2010, at 9:32 AM, Tim Olson wrote:



> 

>

> "I would much rather be flying with 8 gallons in one tank than 4

> gallons in each.  I think that's the issue."

>

> I kind of agree with that statement, mainly from the standpoint of

> fuel unporting during landing.  I don't know that the best balance

> would be 8/0 as opposed to 4/4, but I agree with your point.

> Actually, when I do land with less fuel, it's usually 7/5 or

> something of that nature, so in theory I agree...I only want one

> tank to be near the bottom.  Our comfort with "bottom" is just a

> little different.  With the totalizers and the high accuracy we

> have though, it's probably practical to be able to go 6/2 on that

> split that you mention...that way there's enough to finish a

> landing if needed, with bare minimum fuel, but still plan to finish

> the flight with 6 gallons in the active tank.

>

> I probably, considering the accuracy of my totalizer, take

> conservative fuel planning a little far in that I don't think I've

> ever landed with less than 10 gallons in the RV-10, but I suppose

> if you're going to err, the high side is probably good.  Not that

> what you're doing is an err.  There are more airports in your

> neck of the woods than mine, too, to use as alternates.  And, I

> feel MUCH better about cutting fuel close on my trip to my home

> airport than I do when I'm landing at somewhere unfamiliar.  I

> know how quick I can get on the ground at my home base.

>

> The one point I made about useable fuel though that I think is real

> important is the one about tank angle and useable fuel.  I know my

> floats drop maybe 2-3 gallons or so when I transition from cruise

> to descent with lower fuel levels. I think it would be a good test

> if someone burned a tank down to, say 4 gallons, and then did a

> series of climbs to 10,000 AGL and switched to that tank and did a

> descent, and waited for the fuel to run out.  It may take a while

> to burn 4 gallons at descent power, but some day one of us should

> find out what minimum fuel is at descent angle. Knowing where the

> fuel pickup is, I can see that perhaps minimum fuel may be a gallon

> or as much as 2 gallons, depending on the angle.  I could be wrong.

> Many of us have tested it in level flight though with the same

> results....so I'd assume that one good test in descent would let us

> know.

>

> Regardless of fuel management procedure, what's important is that

> people have a procedure and plan that works for them. It would be

> nice to be able to look back in a few years and say "in the last 10

> years, never has an RV-10 been lost to fuel exhaustion".  It's one

> of those things that just shouldn't happen to people unless they do

> something stupid.

>

> Tim Olson - RV-10 N104CD

>

> On 8/22/2010 10:23 PM, Jesse Saint wrote:

>> 

>> Saint<jesse(at)saintaviation.com>

>>

>> I think the issue is more of a minimum fuel&   where to have it.

>> In normal practice, I burn down 10-15 on one side, switch&   burn

>> down to 10 on the other, then switch.  Only on a long trip where

>> I may be down to reserve do I do as I suggested.  I personally

>> think making minimum fuel of 7 per side too much.  That's 46 gal

>> useable.  If it's a trip that would need 92 gallons, I would

>> split it in half.  If it's a 52-gallon flight, I would not split

>> it up.  Then I would burn down one tank dry or almost so, then

>> fly my last stretch only on the other.  I would much rather be

>> flying with 8 gallons in one tank than 4 gallons in each.  I

>> think that's the issue.

>>

>> I agree that fuel alarms are good and important, but they are

>> there to remind you in case you forget.  On a long flight (like

>> my nonstop from FL to WI for OSH), my main task is to let my

>> autopilot fly the plane while I monitor my fuel, using the fuel

>> computer&   winds aloft info along my route to estimate fuel at

>> destination.  I then decide how close to minimum fuel I will be

>> flying&   burn accordingly.  On a flight like that, the last

>> thing I need is a low fuel alarm.  Also, I have noticed with

>> several systems that if I set an alarm at 5 gallons, I need to

>> keep the tank well above that or well below it to not have the

>> alarm constantly going off as the float bounces when the fuel

>> sloshes.  Once down to 2-3 gallons, a 5-gal alarm will seldom go

>> off after the first time.  Once acknowledged&   noted on the

>> kneeboard, it's known&   that tank not used again.

>>

>> Another thing I do is switch to the full tank one or twice for a

>> minute or two before I go "dry" on one side to verify fuel supply

>> is good&   no flow restrictions.

>>

>> As you said, everybody will have their own way.  This is the way

>> that makes me feel the most comfortable.

>>

>> Jesse Saint I-TEC, Inc. jesse(at)itecusa.org www.itecusa.org

>> www.mavericklsa.com C: 352-427-0285 O: 352-465-4545 F:

>> 815-377-3694

>>

>> Sent from my iPhone

>>

>> On Aug 22, 2010, at 10:28 PM, Tim Olson<Tim(at)myrv10.com>   wrote:

>>

>>> 

>>>

>>> You know, I somewhat feel the same regarding fuel, that I like

>>> to burn a lot off one tank and then I know if my other tank is

>>> plenty full I'm doing great, but...I don't know that I'd take

>>> it quite as far as you do with it. I agree with Jim, I think 5

>>> gallons remaining is a good bottom limit for most of the time.

>>> Here's why...

>>>

>>> First, if you run a tank to the very end, you're going to have

>>> a little more chance to get all the gunk and water that may be

>>> at that low spot in the tank. Granted that since our inlet is

>>> obviously REALLY close to the low spot, it probably doesn't

>>> matter much, but just in concept, I don't know that bottom

>>> feeding on the tank is such a great normal routine.

>>>

>>> Second, at least on my EFIS I have each tank set to alarm below

>>> a certain point.  If I flew one to empty as a routine, I'd have

>>> to silence an alarm, and I don't want to get in the habit of

>>> routinely silencing something like that if I can avoid it.

>>>

>>> Third, like Jim mentioned, it's nice to have a few gallons in

>>> that tank that you just don't use, because those can be used to

>>> fall back on later.  What if suddenly your 2nd and final tank

>>> swallows a gob of water that won't run through and your engine

>>> dies?  If you have even a couple gallons available, you can

>>> make it quite a few more miles to get to an airport.  I'd

>>> always leave 5 gallons just so you have an "out".

>>>

>>> And last, I did a write up once, but on one IFR flight in IMC,

>>> I noticed my tank was using fuel faster than normal.  Stupid

>>> me, I switched to the OTHER tank, well...it wasn't stupid

>>> exactly, but that helped me identify that indeed with the tank

>>> shut off I was draining fuel still.  But what I SHOULD have

>>> done is after verifying, switched back to that tank and used it

>>> up...rather than waste all that fuel.  I had sumped the tanks

>>> in the rain and with all the rain coming down, didn't notice

>>> the sump was still dripping and wasn't sealed well.  If I would

>>> have been using my opposite tank, and I used it to empty, I

>>> could have put myself into a situation where I had one empty

>>> tank and a problem (leak) with the other.

>>>

>>> Anyway, not really wanting to nit pick on a procedure, since

>>> everyone can have their own, but I thought I'd point out a

>>> couple of things on it as to why it's probably best to keep a

>>> few gallons in there.

>>>

>>> I do know what you mean though. I know people that religiously

>>> switch tanks every 30 minutes. That's fine, no problem there,

>>> but I myself would rather maybe burn the top 10 gallons off one

>>> tank, then suck 23 gallons out of the 2nd tank, and then burn

>>> my last 13 gallons off the original tank.  Less switching, and

>>> like you, I like to burn a pile of my fuel off and then have a

>>> good amount in my final tank so I can easily figure that I'll

>>> make my home stretch without needing to swap back to that lower

>>> tank again.

>>>

>>> Tim Olson - RV-10 N104CD do not archive

>>>

>>>

>>> On 8/22/2010 8:33 AM, Jesse Saint wrote:

>>>> 

>>>> Saint<jesse(at)saintaviation.com>

>>>>

>>>> I think each person probably has their personal limit on

>>>> this. Personally, I would much rather have 14 gallons in one

>>>> tank than 7 gallons in each, maybe unless conditions are

>>>> perfectly smooth. Even when flying a 172, on a long trip,

>>>> I'll burn out of both tanks to verify everything is working

>>>> in the system, but will burn one tank down until I start

>>>> losing fuel pressure and then switch so I know all of my fuel

>>>> is available from the current tank (and it also helps to

>>>> verify how much fuel I have - see if my calculations are

>>>> correct, which isn't as much of an issue in the -10).  I do

>>>> this at altitude so, if there's some kind of hickup, there

>>>> would be plenty of time to get it worked out.  I don't think

>>>> I've ever taken the -10 to the point of losing fuel pressure,

>>>> but I've taken it to the point where the float reads zero and

>>>> the flow meter agrees.

>>>>

>>>> That's just the way I do it, and I don't like to get on the

>>>> ground with less than 10 gallons, but all of that on one side

>>>> if I do get that low.

>>>>

>>>> Jesse Saint Saint Aviation, Inc. jesse(at)saintaviation.com C:

>>>> 352-427-0285 F: 815-377-3694

>>>>

>>>> On Aug 22, 2010, at 2:37 AM, AirMike wrote:

>>>>

>>>>> 

>>>>> "AirMike"<Mikeabel(at)Pacbell.net>

>>>>>

>>>>> In re-analyzing my numbers from my trip to OSH - felt that

>>>>> it is best to be on the ground when you have less than 7

>>>>> gallons in each tank. I have very accurate readings from my

>>>>> tank floats and fuel scan is right on the money. Since a

>>>>> big percentage of accidents are from just running out of

>>>>> gas, I'd like any input on minimum usable fuel in the std

>>>>> tanks so that we can all keep a comfortable safety zone.

>>>>

>>>>> I also need this info as I fit out my 90 gallon internal

>>>>> tank for the round-the-poles flight - ok just

>>>>> kidding.......

>>>>>

>>>>> -------- OSH '10 or Bust Q/B - finally done

>>>>>

>>>>>

>>>>> do not archive

>>>>>

>>>>> Read this topic online here:

>>>>>

>>>>> http://forums.matronics.com/viewtopic.php?p=309710#309710

>>>>>

>>>>>

>>>>>

>>>>>

>>>>>

>>>>>

>>>>>

>>>>>

>>>>>

>>>>>

>>>>

>>>>

>>>>

>>>>

>>>>

>>>>

>>>

>>>

>>>

>>>

>>

>>

>>

>>

>>

>

>

rene(at)felker.com
Guest

Posted: Mon Aug 23, 2010 10:10 am Post subject: Miniumum fuel comfort zone

While practicing slips..........un-ported with 12 gallons in the offending

tank.  Be very careful doing slips to landing/off field practice, make sure

you are on the correct tank for the slip direction you have chosen.



I have my alarm set at 5 gallons, and stop using the tank when it hits 3

gallons.  Never fly with less than 10 gallons total except when I was

getting ready for my annual (condition inspection) and tried to burn off

some fuel (excuse to fly) before I drained the tanks to reweight the plane.



Rene' Felker

N423CF

801-721-6080



--

rene(at)felker.com
Guest

Posted: Mon Aug 23, 2010 10:14 am Post subject: Miniumum fuel comfort zone

I do not think it will be blue if it is just water, but I do smell it if it

is not blue enough.  I also drain both tanks into the same bottle and pour

it back in the tank and watch it go in.  As long as the fuel level is high

enough in the tank you will be able to tell if you poured water back in the

tank.



Rene' Felker

N423CF

801-721-6080

--

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Mon Aug 23, 2010 11:59 am Post subject: Miniumum fuel comfort zone

My experience is water does pick up some of the blue dye and smell. I 

feel it, pour a little on the pavement. If it bubbles on the surface, it 

is water, if it sinks in it is likely gas.

On 8/23/2010 11:12 AM, Rene Felker wrote:

[quote] 



 I do not think it will be blue if it is just water, but I do smell it if it

 is not blue enough.  I also drain both tanks into the same bottle and pour

 it back in the tank and watch it go in.  As long as the fuel level is high

 enough in the tank you will be able to tell if you poured water back in the

 tank.



 Rene' Felker

 N423CF

 801-721-6080

 --

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

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