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Calibrating fuel qty gauges
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echristley(at)nc.rr.com
Guest

Posted: Thu Aug 13, 2009 7:22 pm Post subject: Calibrating fuel qty gauges

paul wilson wrote:

 	  Quote: 	
		  

 I guess I don't understand the resistance to functional gauges. Please 

 set me straight.

 Paul

No resistance, Paul.  It is just that I don't think they can be had for 
	


reasonable dollars and effort.  You're trying to hit a moving target.  

Literally, the fuel is jumping around all over the place.  You can have 

mechanics integrate over time to come up with an average level.  You can 

have electronics integrate for you, or you can do the integration on 

your own.



Every design is a different moving target, and every gauge will have a 

slightly different calibration.  Install a simple gauge, then get to 

know how it behaves and you will be better off.



-- 

Ernest Christley, President

Ernest(at)TechnicalTakedown.com



TechnicalTakedown, LLC

www.TechnicalTakedown.com

101 Steep Bank Dr.

Cary, NC  27518

(919) 741-9397

frank.hinde(at)hp.com
Guest

Posted: Fri Aug 14, 2009 6:17 am Post subject: Calibrating fuel qty gauges

Hmm..would seem I stand corrected here..and your right I have never flown behind one.



OK I'll stand behind my fuel flow computer function in mt Dynon EMS then..that is deadly accurate..as long as as I don't get a tank leak at least..



Frank 



--

BobsV35B(at)aol.com
Guest

Posted: Fri Aug 14, 2009 7:06 am Post subject: Calibrating fuel qty gauges

Good Morning Frank,

  

 Is the Dynon unit a fuel flow gauge or a fuel tank gauge?

  

 The Dynon Fuel flow gauge in our grandaughter's homebuilt Legend Cub works  just as good as do the Shadin's we have in our certifed machines.  The fuel  gauge in the Cub is a sight tube and is not worth much at all.

  

 With only nineteen gallons of total fuel capacity, the fuel flow gauge and  totalizer is a very important tool when she flies her Cub from Palo Alto to  Oshkosh and back.

  

 Happy Skies,

  

 Old Bob

  

  In a message dated 8/14/2009 9:19:15 A.M. Central Daylight Time,  frank.hinde(at)hp.com writes:

  	  Quote: 	
		  -->    AeroElectric-List message posted by: "Hinde, Frank George (Corvallis)"    <frank.hinde(at)hp.com>



Hmm..would seem I stand corrected here.and    your right I have never flown behind one.



OK I'll stand behind my fuel    flow computer function in mt Dynon EMS then..that is deadly accurate..as long    as as I don't get a tank leak at least..



Frank 



-----Original    Message-----

From: owner-aeroelectric-list-server(at)matronics.com    [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of John    Morgensen

Sent: Thursday, August 13, 2009 3:25 PM

To:    aeroelectric-list(at)matronics.com

Subject: Re: Re:    Calibrating fuel qty gauges



--> AeroElectric-List message posted by:    John Morgensen 

--> <john(at)morgensen.com>



Hinde, Frank    George (Corvallis) wrote:

 	  Quote: 	
		   --> AeroElectric-List message posted by:    "Hinde, Frank George 

 --> (Corvallis)"    <frank.hinde(at)hp.com>



 The only level guge I would rely on    would be a sight tube, which cannot lie.

   

I am going to    go out on a limb here and guess that you have never enjoyed flying a Grumman    Yankee with 11 gallons in each wing and an O-320. 
	




John    Morgensen

RV4

Grumman AA1B-150 (For Sale)

RV9A  ================================================= Use   utilities  Day  ================================================               - MATRONICS WEB FORUMS  ================================================             - List Contribution Web Site  sp;                             ===================================================



	


 

  [quote][b]

frank.hinde(at)hp.com
Guest

Posted: Fri Aug 14, 2009 7:48 am Post subject: Calibrating fuel qty gauges

The Dynon is actually  both. Its an integrated engine managemnt system..in other words it takes  numerous inputs (CHT, EGIT, RPM, MP, OAT etc) into a single 4" screen on the PX  side that is swapable to the EFIS on my side..you can also swap the EFIS to the  EMS to let the PX have a full flight deck..pretty slick.

  

 Anyway, the flowmeter  uses one of those little turbine units as the flow sensor in the line feeding  the engine. The Dynon then counts the pulses to tell you have much fuel you have  burned. It works the same way as a lot of the experimental fuel flow  transducers.

  

 The Van's standard  resistive float tank senders appear to be pretty accurate too and these are also  read by the Dynon...I'd never trust them fully though.

  

 Palo Alto to OSH and back  in a CUB?..Woah, she has more patience than I do..

  

 The RV cruises at about  160kts on roughly 7 gallons an hour of autofuel (I can get that down to about  6.6GPH at 12 to 14k) ...And with 42 gallons I can almost make western Oregon to  Fort collins Colorado in one tankful..but thats a bit tight for my comfort  margins and the Wife won't stay in the airplane for 5.5 hours...

  

 Frank



   From: owner-aeroelectric-list-server(at)matronics.com  [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of  BobsV35B(at)aol.com

Sent: Friday, August 14, 2009 7:55  AM

To: aeroelectric-list(at)matronics.com

Subject: Re:  Re: Calibrating fuel qty gauges

 

 Good Morning Frank,

  

 Is the Dynon unit a fuel flow gauge or a fuel tank gauge?

  

 The Dynon Fuel flow gauge in our grandaughter's homebuilt Legend Cub works  just as good as do the Shadin's we have in our certifed machines.  The fuel  gauge in the Cub is a sight tube and is not worth much at all.

  

 With only nineteen gallons of total fuel capacity, the fuel flow gauge and  totalizer is a very important tool when she flies her Cub from Palo Alto to  Oshkosh and back.

  

 Happy Skies,

  

 Old Bob

  

  

 



  [quote][b]

BobsV35B(at)aol.com
Guest

Posted: Fri Aug 14, 2009 8:25 am Post subject: Calibrating fuel qty gauges

Good Morning Frank,

  

 Sounds like you have a similar fuel flow setup to what our granddaughter  has.   Works great!

  

 She finished the Cub just in time to take it to Sun n' Fun 2008. I helped  by putting twenty-five of the required forty hours on it before she and her  father took it to Florida. That same year, she flew it solo to Oshkosh and she  repeated that trip this year. Her Cub was on display at Kid Venture.

  

 She averages about eighty-five to ninety MPH. Sure is a good time builder,  but a larger fuel capacity would be nice. Legend Cub is now offering bigger fuel  tanks.

  

 Happy Skies,

  

 Old Bob

  

  In a message dated 8/14/2009 10:49:59 A.M. Central Daylight Time,  frank.hinde(at)hp.com writes:

  	  Quote: 	
		     Palo Alto to OSH and    back in a CUB?..Woah, she has more patience than I  do..

	


 

  [quote][b]

Speedy11(at)aol.com
Guest

Posted: Fri Aug 14, 2009 8:39 am Post subject: Calibrating fuel qty gauges

Hmmm ... I hadn't considered a ground problem.  Since I was getting  some readings (and output checked with meter) I had assumed the wiring to be  suitable.  Maybe it's not.

 I'll check.

 Stan Sutterfield

 Do not archive

  	  Quote: 	
		  Any    chance of a bad ground or some other noise working its way into    the

system?  It doesn't sound like sloshing error, and maybe not a    sensor

problem - though I don't know enough to rule that out.  It also    doesn't

sound like a calibration problem.  I would stop calibrating as    I don't

think it will fix the problem (until you fix the real    problem). 	


 

  

 

  [quote][b]

Speedy11(at)aol.com
Guest

Posted: Fri Aug 14, 2009 9:26 am Post subject: Calibrating fuel qty gauges

Old Bob,

 My thoughts exactly.  I'm too timid to express them because of getting  flamed on the forum.

 But, you expressed my thoughts precisely.  The T-38 was always flown  to 20 minutes fuel remaining.  We did the same in the F-4, F-5 and  F-16.  Once I was chasing a F-16 student on initial solo and he landed,  blew a tire and closed the only runway at MacDill.  My 20 minute reserve  was quite sufficient.  Accel to 450 on the deck, climb at .87 to FL400 and  do an idle descent to final at Patrick.  Still landed with plenty of  fuel.  The key is to have a suitable back up plan.  In custom built  aircraft, we don't need the ability to zoom climb to the moon - we simply need a  suitable backup plan should something go wrong with the primary plan.  If  the back plan is good, then flying to FAA fuel minimums is fine.

  

 I like to know how much fuel is on board at any given time.  Then I  can make decisions based on that information.  The quantity information can  be obtained from a number of sources - gauges, optical sensors with warning  lights, preflight measurement, engine monitor calculations, and my own  calculations.

 I desire accurate fuel gauges.  If the accuracy of my  fuel gauges is questionable, then I must err on the conservative side  which means I cannot utilize my aircraft to its optimum.

  

 I agree with Old Bob on this subject.

  

 Stan Sutterfield

  

  	  Quote: 	
		  Good    Afternoon 'Lectric Bob,



This may be just an exercise in semantics, but    I do disagree with the  

philosophy I think you are espousing.    



There is nothing wrong with planning on arriving at a safe landing    spot  

with ten to fifteen minutes of fuel as long as you are    confident you will be 

at  that spot at the appointed time. 



To    say we should always have something beyond what is required is too broad    

for my liking. On those few occasions when I had the pleasure of flying a    

T-38,  we landed every time with "Bingo" fuel. In that airplane,    Bingo fuel 

was a bit  less than twenty minutes worth. Good enough for    one full power go 

around and not  much more. 



We pay a LOT of    money for every pound of payload we put in our flying  

machines. I    think it is very rational to reduce the amount of fuel down to what



is    required for the mission at hand. My cross country flyer has tip tanks 

and    it  can fairly easily fly twelve hours with full tanks. My planning for    

that  airplane often has me arriving with less than one hours worth    of fuel. 

If I was  able to be as certain of landing field    availability as I was when 

flying the  T-38 and as confident as I was    of the accuracy of the fuel 

gauges, I would not  hesitate to fly my    long ranger down to a Bingo fuel of 

twenty minutes.



Back when I was    doing sling work with a helicopter, we added fuel for each  

trip    lifting air conditioners to a roof top. Carrying no more than about    

five  minutes of reserve fuel, we managed to get more air    conditioners per day



up on  top of those roofs. The reserve fuel    planned on should be based on 

the accuracy  of the fuel indicating    system and the reliability of the 

landing estimate 



To do otherwise    is as foolish as asking that every airplane be fitted with  

four    engines just in case one of them happens to quit. We have decided that    

a  good single engine provides adequate safety for many of us. The    same 

thing goes  for carrying extra fuel. Every ounce we carry that    is not needed 

for the task at  hand costs us money and    $time$.



I prefer to know how much fuel is on board and how much I want    when I  land.



Just my thoughts



Happy Skies,



Old    Bob 	


 

  

 

  [quote][b]

Speedy11(at)aol.com
Guest

Posted: Fri Aug 14, 2009 9:35 am Post subject: Calibrating fuel qty gauges

VERY well said!

  

 Now if I could only get accurate fuel gauges.

  

 Stan Sutterfield

 Do not archive

  

  	  Quote: 	
		  Good    Afternoon Old Ian,



If you are saying you disagree with my philosophy,    that is just fine. 



I rarely plan to arrive with only ten minutes of    reserve fuel, but there  

are conditions where I would be happy to do    so. The T-38 flights at Edwards 

were  just such flights. 



My    personal planning at the average multi runway airport is forty-five     

minutes. If there is only one runway, I want a close by alternate and fuel    to 



get there 



It All Depends!



That is more than what the    FAA requires, but it is what I like to have.  

However, I do NOT wish    to arrive anywhere without knowing accurately how much 



fuel I do have    on board. If I know that amount due to careful timing or by 

the     trust I have in my fuel gauges, I still want to know the amount, not    

just  that there is an indeterminate large amount of fuel on    board.



You speak quite sarcastically about an airplane that was    arriving at "your" 

destination and who was not listening to your    pronouncements on the radio.



We all must remember that it is still    legal for aircraft that have no radio 

to be using most airspace in this    nation. You may not think that is 

proper, but  if you are flying in    pilot controlled airspace, you should always

be 

aware that  it is    quite likely that a NORDO aircraft may be sharing "your" 

airspace.    



The most likely cause of a NORDO conflict is when you or the pilot of    the  

other aircraft have made the error of not tuning the correct    frequency, 

flipping  the right audio switch, pressing the wrong mike    button or other 

similar pilot  failures of omission or commission. I    know I have made all of those



errors at  one time or another.    While I try very hard to reduce my errors, 

I know that I am  human    and all of us humans do make mistakes. Not only 

that, but radios DO     fail.



That is what planning is all about. We plan what we need and how    to handle  

what we don't expect. Such planning requires careful    analysis of the 

conditions  that prevail and that includes a good    idea as to how much fuel we have



at any  particular moment. I do    not wish to carry somewhere between three 

to five hours  of fuel when    I have no idea which amount of fuel is actually 

in my flying     machine.



Whether I plan on landing with ten minutes fuel or four hours    fuel, I want  

to know how much there is and where it is    located.



Happy Skies,



Old Bob

Didn't get that way by making    Wild Guesses!

	


 

  

 

  [quote][b]

Speedy11(at)aol.com
Guest

Posted: Fri Aug 14, 2009 9:52 am Post subject: Calibrating fuel qty gauges

Bob,

 The pilots on this forum are every bit as capable as professional pilots -  including optimizing the amount of fuel on board.  One simply must plan the  flight including a back up plan (maybe two or three), crosscheck himself along  the way, and execute the most appropriate of the plans - with Plan A being  primary.

 Regarding using accurate fuel information of make high risk "press-on"  decisions, the pilot must consider all information before making a decision  - whether to press on or to divert.  WX, alternate airports, terrain,  aircraft familiarity, airport familiarity, fatigue, and fuel quantity are all  inputs to the decision process.  A decision to press on is not necessarily  exponentially higher risk than a diversion plan.  In fact, it may be less  risk if the destination airport is familiar with a suitable length runway  whereas the divert airport is unfamiliar with a minimum length runway.   There are many variables - one reason flying is fun.

 Now about getting those accurate fuel gauges with which to make my divert  decision.

 Stan Sutterfield

  

  	  Quote: 	
		     But keep in mind my friend that we're not here    to

   offer advice and training to professional    pilots.

   Only a small percentage of our 1800 readers fly    for

   a living and many if not most are under 300    hour

   pilots.

.........

   One may argue that having accurate fuel    data

   can trigger an early termination of flight    to

   avoid the unhappy day . . . but it can also

      be combined with other data to make a press-on

   decision with    an exponential rise in risk. 	
 

  

 

  [quote][b]

Speedy11(at)aol.com
Guest

Posted: Fri Aug 14, 2009 9:57 am Post subject: Calibrating fuel qty gauges

Terry,

 How about a visit from another builder next time I'm in Seattle?  I'd  like to see your project.

 Stan Sutterfield

 www.rv-8a.net

 Do not archive

  	  Quote: 	
		  My    RV-8A, if it every gets finished, has low fuel warning lights similar    to

what Bob N. has described that I bought as a kit a few years ago. It    already

has capacitive gauges and a fuel flow    sender.

Terry



RV-8A 



Seattle 	


 

  

 

  [quote][b]

Speedy11(at)aol.com
Guest

Posted: Fri Aug 14, 2009 10:05 am Post subject: Calibrating fuel qty gauges

Absolutely correct.

  

 Stan

 Do not archive

  

  	  Quote: 	
		  Knowing    where the edge is may increase the comfort of going close to the 

edge, but    not knowing where the edge is attempting to make decisions 

with no    reliable data.



In short, would we rather make decisions from hard    facts, or soft 

ambiguity.  I would rather have precise knowledge of    fuel quantity, and 

then rely on discipline to plan appropriately compared    to never being 

sure.



Chuck Jensen 	


 

  

 

  [quote][b]

Speedy11(at)aol.com
Guest

Posted: Fri Aug 14, 2009 10:11 am Post subject: Calibrating fuel qty gauges

Thank you, Paul!

  

 Stan

 Do not archive

  

  	  Quote: 	
		  The poor    guy wants a reliable fuel quantity meter. He did not ask 

about proper    flight planning and all you guys philosophy on that wrong subject.



If    there is an instrument in the plane it should reflect what is 

going    on.  Like oil pressure should read correctly in flight as well 

as on    the ground. same thing with the volt meter etc.

Level sensing fuel gauges    do not give reasonable accuracy in flight 

but usually give good data on    the ground. A flow meter gauge reads 

fuel remaining any time it is powered    on.



I cite the example of the famous Cessna fuel cap o-ring. On a    flight 

from Denver to Cheyenne with full tanks. The poor pilot arrived in    

Cheyenne with no reserve. To bad he did not have a reliable gauge 

that    told him the fuel remaining was drastically decreasing. Even if 

he watched    his gauge he probably did not believe it because it is so 

erratic in    flight. For sure this was not a flight planning issue.



So a functional    gauge especially with a warning feature would be 

desirable in case it is    desired to monitor a fuel related failure mode.



Bottom line is we do    not have to live with garbage gauges that have 

been used for years or    newfangled level sensing gauges that only are 

good on the ground.



I    guess I don't understand the resistance to functional gauges. 

Please set    me straight.

Paul

	


 

  

 

  [quote][b]

Bruce(at)glasair.org
Guest

Posted: Fri Aug 14, 2009 10:32 am Post subject: Calibrating fuel qty gauges

I believe the answer is a calibrated capacitance fuel gage system.  

     

Bruce

 www.Glasair.org   

  

--

frank.hinde(at)hp.com
Guest

Posted: Fri Aug 14, 2009 11:23 am Post subject: Calibrating fuel qty gauges

But the bigger question  is..

  

 Does does one become  content with flying an RV 8 after an F16??..

  

 Frank

  

 Do not  archive



   From: owner-aeroelectric-list-server(at)matronics.com  [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of  Speedy11(at)aol.com

Sent: Friday, August 14, 2009 10:23  AM

To: aeroelectric-list(at)matronics.com

Subject:  Re: Calibrating fuel qty gauges

 

  Old Bob,

 My thoughts exactly.  I'm too timid to express them because of getting  flamed on the forum.

 But, you expressed my thoughts precisely.  The T-38 was always flown  to 20 minutes fuel remaining.  We did the same in the F-4, F-5 and  F-16.  Once I was chasing a F-16 student on initial solo and he landed,  blew a tire and closed the only runway at MacDill.  My 20 minute reserve  was quite sufficient.  Accel to 450 on the deck, climb at .87 to FL400 and  do an idle descent to final at Patrick.  Still landed with plenty of  fuel.  The key is to have a suitable back up plan.  In custom built  aircraft, we don't need the ability to zoom climb to the moon - we simply need a  suitable backup plan should something go wrong with the primary plan.  If  the back plan is good, then flying to FAA fuel minimums is fine.

  



  [quote][b]

BobsV35B(at)aol.com
Guest

Posted: Fri Aug 14, 2009 11:51 am Post subject: Calibrating fuel qty gauges

Good Afternoon Stan,

  

 Thanks for the comment!

 Nice to have company.

  

 Planning is Planning. What you do is dependent on the accuracy of the data  available. Doesn't change if we are flying a 747, DC-3, J-3 Cub, T-38, or RV-3  (I have flown all of those except the RV-3. <G>)

  

 Happy Skies,

  

 Old Bob

  

  In a message dated 8/14/2009 12:28:05 P.M. Central Daylight Time,  Speedy11(at)aol.com writes:

  	  Quote: 	
		        Old Bob,

   My thoughts exactly.  I'm too timid to express them because of    getting flamed on the forum.

   But, you expressed my thoughts precisely.  The T-38 was always flown    to 20 minutes fuel remaining.  We did the same in the F-4, F-5 and    F-16.  Once I was chasing a F-16 student on initial solo and he landed,    blew a tire and closed the only runway at MacDill.  My 20 minute reserve    was quite sufficient.  Accel to 450 on the deck, climb at .87 to FL400    and do an idle descent to final at Patrick.  Still landed with plenty of    fuel.  The key is to have a suitable back up plan.  In custom built    aircraft, we don't need the ability to zoom climb to the moon - we simply need    a suitable backup plan should something go wrong with the primary plan.     If the back plan is good, then flying to FAA fuel minimums is fine.

    

   I like to know how much fuel is on board at any given time.  Then I    can make decisions based on that information.  The quantity information    can be obtained from a number of sources - gauges, optical sensors with    warning lights, preflight measurement, engine monitor calculations, and my own    calculations.

   I desire accurate fuel gauges.  If the accuracy of my    fuel gauges is questionable, then I must err on the conservative    side which means I cannot utilize my aircraft to its optimum.

    

   I agree with Old Bob on this subject.

    

   Stan Sutterfield

    

    	  Quote: 	
		  Good      Afternoon 'Lectric Bob,



This may be just an exercise in semantics,      but I do disagree with the  

philosophy I think you are espousing.      



There is nothing wrong with planning on arriving at a safe landing      spot  

with ten to fifteen minutes of fuel as long as you are      confident you will be 

at  that spot at the appointed time.      



To say we should always have something beyond what is required is      too broad 

for my liking. On those few occasions when I had the pleasure      of flying a 

T-38,  we landed every time with "Bingo" fuel. In that      airplane, Bingo fuel 

was a bit  less than twenty minutes worth.      Good enough for one full power go 

around and not  much more.      



We pay a LOT of money for every pound of payload we put in our      flying  

machines. I think it is very rational to reduce the amount      of fuel down to what



is required for the mission at hand. My cross      country flyer has tip tanks 

and it  can fairly easily fly twelve      hours with full tanks. My planning for 

that  airplane often has me      arriving with less than one hours worth of fuel. 

If I was  able to      be as certain of landing field availability as I was when 

flying      the  T-38 and as confident as I was of the accuracy of the fuel      

gauges, I would not  hesitate to fly my long ranger down to a Bingo      fuel of 

twenty minutes.



Back when I was doing sling work with a      helicopter, we added fuel for each  

trip lifting air conditioners      to a roof top. Carrying no more than about 

five  minutes of reserve      fuel, we managed to get more air conditioners per day



up on  top      of those roofs. The reserve fuel planned on should be based on 

the      accuracy  of the fuel indicating system and the reliability of the      

landing estimate 



To do otherwise is as foolish as asking that      every airplane be fitted with  

four engines just in case one of      them happens to quit. We have decided that 

a  good single engine      provides adequate safety for many of us. The same 

thing goes  for      carrying extra fuel. Every ounce we carry that is not needed 

for the      task at  hand costs us money and $time$.



I prefer to know how      much fuel is on board and how much I want when I  land.



Just my      thoughts



Happy Skies,



Old Bob 	


   

    

   

      

 	  Quote: 	
		  



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List href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matronics.com/Navigator?AeroElectric-List

====================================

ms.matronics.com/">http://forums.matronics.com

====================================

tp://www.matronics.com/contribution">http://www.matronics.com/contribution

====================================



	
	


 

  [quote][b]

BobsV35B(at)aol.com
Guest

Posted: Fri Aug 14, 2009 11:55 am Post subject: Calibrating fuel qty gauges

Good Afternoon Frank,

  

 I certainly cannot speak for Stan, but I am very happy with the aircraft I  now have available. Not sure whether content is the word for my present state,  but it beats being grounded!

  

 Happy Skies,

  

 Old Bob

 Do Not Archive

  

  In a message dated 8/14/2009 2:24:37 P.M. Central Daylight Time,  frank.hinde(at)hp.com writes:

  	  Quote: 	
		     But the bigger question    is..

    

   Does does one become    content with flying an RV 8 after an F16??..

    

   Frank

    

   Do not    archive



         From: owner-aeroelectric-list-server(at)matronics.com    [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of    Speedy11(at)aol.com

Sent: Friday, August 14, 2009 10:23    AM

To: aeroelectric-list(at)matronics.com

Subject:    Re: Calibrating fuel qty gauges

   

      Old Bob,

   My thoughts exactly.  I'm too timid to express them because of    getting flamed on the forum.

   But, you expressed my thoughts precisely.  The T-38 was always flown    to 20 minutes fuel remaining.  We did the same in the F-4, F-5 and    F-16.  Once I was chasing a F-16 student on initial solo and he landed,    blew a tire and closed the only runway at MacDill.  My 20 minute reserve    was quite sufficient.  Accel to 450 on the deck, climb at .87 to FL400    and do an idle descent to final at Patrick.  Still landed with plenty of    fuel.  The key is to have a suitable back up plan.  In custom built    aircraft, we don't need the ability to zoom climb to the moon - we simply need    a suitable backup plan should something go wrong with the primary plan.     If the back plan is good, then flying to FAA fuel minimums is fine.

    



 	  Quote: 	
		  



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====================================

ms.matronics.com/">http://forums.matronics.com

====================================

tp://www.matronics.com/contribution">http://www.matronics.com/contribution

====================================



	
	


 

  [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Aug 14, 2009 4:44 pm Post subject: Calibrating fuel qty gauges

 	  Quote: 	
		  I cite the example of the famous Cessna fuel cap o-ring. On a flight 

from Denver to Cheyenne with full tanks. The poor pilot arrived in 

Cheyenne with no reserve. To bad he did not have a reliable gauge 

that told him the fuel remaining was drastically decreasing. Even if 

he watched his gauge he probably did not believe it because it is so 

erratic in flight. For sure this was not a flight planning issue.


	


   This is why the electronic dip-sticks at the

   low fuel warning level is so important. Nothing

   to calibrate. It's ON or OFF. It's independent

   of the more complex gaging systems requiring

   calibration.

 	  Quote: 	
		  So a functional gauge especially with a warning feature would be 

desirable in case it is desired to monitor a fuel related failure mode.


	


   How about independent gaging and warning systems?

   One helps keep tabs on functionality of the other

   by observing behaviors from one flight to the next.



 	  Quote: 	
		  Bottom line is we do not have to live with garbage gauges that have 

been used for years or newfangled level sensing gauges that only are 

good on the ground.



I guess I don't understand the resistance to functional gauges. 

Please set me straight.


	


   No resistance whatsoever. Only a caution about

   understanding their functionality, risks for failure

   by mis-reporting real fuel level and loss of the

   pilot's healthy skepticism. It's my client's

   charter that I help produce a best-we-know-how-to-

   do in fuel gaging to replace the best we knew how

   to do 25 years ago. I intend to deliver on that

   charter. At the same time, my studies of older

   designs (and bad days in the cockpit that began with

   reliance on those designs) reminds me of a very

   wise axiom: "Trust but verify".

        Bob . . .



         ---------------------------------------

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

         ---------------------------------------

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Aug 14, 2009 6:24 pm Post subject: Calibrating fuel qty gauges

At 12:50 PM 8/14/2009, you wrote:

  	  Quote: 	
		   Bob,

 The pilots on this forum are every bit as capable as professional pilots - including optimizing the amount of fuel on board.  One simply must plan the flight including a back up plan (maybe two or three), crosscheck himself along the way, and execute the most appropriate of the plans - with Plan A being primary.

 Regarding using accurate fuel information of make high risk "press-on" decisions, the pilot must consider all information before making a decision - whether to press on or to divert.  WX, alternate airports, terrain, aircraft familiarity, airport familiarity, fatigue, and fuel quantity are all inputs to the decision process.  A decision to press on is not necessarily exponentially higher risk than a diversion plan.  In fact, it may be less risk if the destination airport is familiar with a suitable length runway whereas the divert airport is unfamiliar with a minimum length runway.  There are many variables - one reason flying is fun.

 Now about getting those accurate fuel gauges with which to make my divert decision.

 Stan Sutterfield 	


   Stan, you have missed the point. I was not suggesting

   that ANY particular individual on this List was

   incapable of operating an airplane in a prudent

   manner. I WAS counseling caution with respect to

   pushing the limits of endurance based on FAITH in

   a fuel gaging system that was not personally calibrated

   and verified by the owner/operator. Whether or not

   that caution applies to you is something only

   you can judge  . . . it was not offered to you

   or anyone in particular.



   We've got builders wrestling with getting the

   voltage regulators set right. Is it a good idea

   to take bullet points from the 4-color brochure of any

   OBAM aircraft gaging system and encourage our

   fellow builders to take them as gospel?



   We've read about the experiences and sentiments

   of individuals who routinely and confidently

   ran out the slosh many times in airplanes. But just

   a few weeks ago we discussed the sad demise of a

   builder who appeared to have lot of confidence from

   source(s) unknown, yet his confidence proved fatal.



   I'm working an accident now where a builder cherry

   picked pieces of ideas from the 'Connection, from

   a radio installation manual, and what appears to

   have been advice from a friend. These were assembled

   into a system designed to fail . . . and it did.



   The thrust of my postings was two-fold . . . and

   you've been around here long enough to understand

   it as well as anyone. First, there is no substitute

   for understanding the capabilities and limits of

   any system upon which you plan to push the limits

   of performance. Second, there is a well tested, legacy

   process by which failure tolerant systems are designed

   where an UNWILLINGNESS to push out to fuzzy limits

   can be a useful component of raising confidence level

   in the outcome of any flight. This is about risk

   reduction.



   It is technologically feasible to build, calibrate,

   verify and maintain an accurate fuel gage that

   would allow the willing pilot to taxi up to the

   pumps with one gallon remaining . . . or fumes for

   that matter. But I will never suggest that anyone

   strive for that kind of performance as a design goal.

   Further, I'm aware of no fuel gage presently offered

   to the OBAM aircraft market capable of  offering

   that performance. Even if the gage existed and proved

   capable, it would be wise for the supplier of that

   product to discourage tugging the tail of the

   fuel tiger.



   I've spent many years working in a flight test environment

   where pilots and program managers routinely got in

   my face demanding assurances that the thing I just

   bolted to their airplane wasn't going to cause a bad

   day in the cockpit. I can also state that if any one

   of those pilots taxied to the ramp with 10 minutes

   remaining and then claimed that he could do it

   routinely and at will would not be working where I

   worked very long. Because we all know that fuel

   gages on even our engineering flight test aircraft

   are never calibrated and maintained to that degree of

   accuracy.



   You're encouraged to craft and operate your airplane

   in any manner for which you have necessary skill and

   acquired confidence. Please don't paint me with the

   tar brush for suggesting that 1800 folks besides you

   avoid landing with all the low fuel warning lights

   flashing and the needles banging the stops. 



   I would be severely distressed to learn that the RV-10

   went down because of some erroneous notions or shaky

   ideas the pilot acquired on this List. Balance and

   maneuvering skills necessary to ride a bike does not

   make one good at walking the high wire.  



   Bob . . .     [quote][b]

BobsV35B(at)aol.com
Guest

Posted: Fri Aug 14, 2009 8:21 pm Post subject: Calibrating fuel qty gauges

Good Evening 'Lectric Bob,

  

 It appears to me that this discussion is getting way out of hand   

  

 I know I should leave it alone.

  

 Nevertheless, I do not think you, Stan, or I are very far apart in what we  really want to see happen. 

  

 None of us want to see anyone run out of fuel. 

  

 I have mentioned occasions where I have found five to ten minutes of fuel  to be perfectly safe, but none of those were in conditions where the 30 minute  FAA minimum was applicable. They were in operations where the conditions and  equipment warranted such operations and they were in complete accordance with  procedures approved by the ruling authority of that particular operation.  

  

 I very rarely operate a trip where I plan on landing with as low a fuel  quantity as the FARs allow. That there are cases where such operations are at  least as safe as carrying five hours of extra fuel is not important. 

  

 What is important is that a rational decision has been made that is in  conformance with the regulations established for that particular operation.  

  

 My WAG is that it's much more likely that a person who has no idea how much  fuel is on board is more likely to run out of fuel than will a person who knows  exactly how much fuel is available.

  

 Safety of flight is a function of acquiring data and making sensible  decisions based on that data. We are given guidance on those decisions by  various governing bodies. As long as we obey the rules and do the planning we  are expected to do, all should be well. Or, at least, well within the level of  risk accepted for that operation.  

  

 It is obvious to me that we are looking at this problem from different  perspectives. It is too bad that we do not seem to be able to find a common  ground, but I think we can all agree that having accurate fuel flow equipment is  a good thing and having accurate knowledge of the fuel on board is a good  thing.

  

 Any chance of agreement on those two points?

  

 Happy Skies,

  

 Old Bob

  

  

 In a message dated 8/14/2009 9:25:38 P.M. Central Daylight Time,  nuckolls.bob(at)aeroelectric.com writes:

   	  Quote: 	
		  At 12:50    PM 8/14/2009, you wrote:

    	  Quote: 	
		  Bob,

The pilots on this forum are every bit as capable as      professional pilots - including optimizing the amount of fuel on      board.  One simply must plan the flight including a back up plan (maybe      two or three), crosscheck himself along the way, and execute the most      appropriate of the plans - with Plan A being primary.

Regarding using      accurate fuel information of make high risk "press-on" decisions, the pilot      must consider all information before making a decision - whether to press on      or to divert.  WX, alternate airports, terrain, aircraft familiarity,      airport familiarity, fatigue, and fuel quantity are all inputs to the      decision process.  A decision to press on is not necessarily      exponentially higher risk than a diversion plan.  In fact, it may be      less risk if the destination airport is familiar with a suitable length      runway whereas the divert airport is unfamiliar with a minimum length      runway.  There are many variables - one reason flying is fun.

Now      about getting those accurate fuel gauges with which to make my divert      decision.

Stan Sutterfield 	


  Stan, you have    missed the point. I was not suggesting

  that ANY particular    individual on this List was

  incapable of operating an airplane in a    prudent

  manner. I WAS counseling caution with respect to

     pushing the limits of endurance based on FAITH in

  a fuel gaging    system that was not personally calibrated

  and verified by the    owner/operator. Whether or not

  that caution applies to you is    something only

  you can judge  . . . it was not offered to    you

  or anyone in particular.



  We've got builders    wrestling with getting the

  voltage regulators set right. Is it a    good idea

  to take bullet points from the 4-color brochure of    any

  OBAM aircraft gaging system and encourage our

  fellow    builders to take them as gospel?



  We've read about the    experiences and sentiments

  of individuals who routinely and    confidently

  ran out the slosh many times in airplanes. But    just

  a few weeks ago we discussed the sad demise of a

     builder who appeared to have lot of confidence from

  source(s)    unknown, yet his confidence proved fatal.



  I'm working an    accident now where a builder cherry

  picked pieces of ideas from the    'Connection, from

  a radio installation manual, and what appears    to

  have been advice from a friend. These were assembled

     into a system designed to fail . . . and it did.



  The thrust of    my postings was two-fold . . . and

  you've been around here long    enough to understand

  it as well as anyone. First, there is no    substitute

  for understanding the capabilities and limits    of

  any system upon which you plan to push the limits

  of    performance. Second, there is a well tested, legacy

  process by which    failure tolerant systems are designed

  where an UNWILLINGNESS to push    out to fuzzy limits

  can be a useful component of raising confidence    level

  in the outcome of any flight. This is about risk

     reduction.



  It is technologically feasible to build,    calibrate,

  verify and maintain an accurate fuel gage that

     would allow the willing pilot to taxi up to the

  pumps with one    gallon remaining . . . or fumes for

  that matter. But I will never    suggest that anyone

  strive for that kind of performance as a design    goal.

  Further, I'm aware of no fuel gage presently offered

     to the OBAM aircraft market capable of  offering

  that    performance. Even if the gage existed and proved

  capable, it would    be wise for the supplier of that

  product to discourage tugging the    tail of the

  fuel tiger.



  I've spent many years working    in a flight test environment

  where pilots and program managers    routinely got in

  my face demanding assurances that the thing I    just

  bolted to their airplane wasn't going to cause a bad

     day in the cockpit. I can also state that if any one

  of those pilots    taxied to the ramp with 10 minutes

  remaining and then claimed that    he could do it

  routinely and at will would not be working where    I

  worked very long. Because we all know that fuel

  gages on    even our engineering flight test aircraft

  are never calibrated and    maintained to that degree of

  accuracy.



  You're    encouraged to craft and operate your airplane

  in any manner for    which you have necessary skill and

  acquired confidence. Please don't    paint me with the

  tar brush for suggesting that 1800 folks besides    you

  avoid landing with all the low fuel warning lights

     flashing and the needles banging the stops. 



  I would be severely    distressed to learn that the RV-10

  went down because of some    erroneous notions or shaky

  ideas the pilot acquired on this List.    Balance and

  maneuvering skills necessary to ride a bike does    not

  make one good at walking the high wire.  



  Bob    . . .  	  Quote: 	
		  



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  [quote][b]

klehman(at)albedo.net
Guest

Posted: Sat Aug 15, 2009 4:38 am Post subject: Calibrating fuel qty gauges

There are simple ways of achieving some of these goals in some aircraft. 

I have a two gallon gravity fed vented header tank which is also a great 

gascolator. A low cost float switch (from aircraft spruce) triggers a 

large two color flashing LED if it is not full, which means it gets 

quiet in 20 min. for me unless I switch tanks or land as appropriate. No 

sloshing effects in a full header tank. No concerns about air bubbles, 

unuseable fuel, or maneuvering with low fuel in the main tanks. It has a 

press to test button for no good reason other than it makes me feel good.

The sight gauges in my wing tanks are damped with a restriction and 

calibrated in blue on the forward side for flight and in red on the rear 

side for ground (tail dragger). Certainly not foolproof but surprisingly 

accurate for confirming fuel remaining agrees with what I estimate 

should be there. Certainly accurate to within one gallon in my 24 gallon 

wing tanks although I don't remember looking at them when in head 

bumping seat belt tugging turbulence. They also verify how much fuel is 

added to the tanks quite accurately. Even parked on a slight left to 

right slope, the error in one tank tends to be cancelled out by the 

error in the other tank. Clear teflon sight gauges are shatter proof and 

will last forever regardless of what fuel one uses.

Ken

Robert L. Nuckolls, III wrote:

 	  Quote: 	
		   At 01:14 PM 8/14/2009, you wrote:

> Geek, Nerd, or Ernest,

> I'm surprised you are willing to accept the poor excuse for fuel 

> measurement we've had for the past 60 years.  With your skills, I 

> would have expected you to jump on this challenge and solve it.

> There must be a solution.

   Design goals for the system I'm working on now include

   in-situ calibration at intervals equal to 5% of full

   capacity. So an accuracy on the order of 2% of tank

   capacity seems achievable. But even if it becomes

   a product on either the TC or OBAM side of the house,

   I'd still be reluctant to recommend that anyone plan

   a flight that draws a tank down to less than 30 minutes

   total fuel aboard.

        Bob . . .

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