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Firedog(at)visi.com
Guest

Posted: Sun Jul 24, 2011 1:39 pm Post subject: fuel flow from tanks

Good morning all,

 

The fuel tank gremlins have struck again.  I need some guidance.

 

Yesterday’s flight (now 3 days ago):

1983 CJ 6A, no mods to the fuel system…straight and level flight, temps in the mid 80’s, flying 2-3 thousand feet AGL, (avg elevation 1000 ft.), slight headwind on the nose, 155 lb pilot, no GIB. 

 

No squawks on my outbound flight…fairly equal fuel usage from both tanks.

I refilled upon arrival at my destination…the plane sat for 6 hours in the sun. Only squawk on taxi out was that the right brake was locked up…a little S turn on the ramp fixed that…but let me get to the issue.

 

On my return flight, the left tank was drawn down  to 1.0 on the gauge (16.5 gallon when I later refueled).  The right tank showed between 5 and 6 favoring the 6 (4.0 gallons used).  I tried the shake the plane in flight, crabbing to the right and to a lesser degree tipping my left wing down… nothing cured the issue.  I somehow suspect that there is a “pilot error” involved here, I just can’t figure it out.

 

Q 1:  Has anyone else experienced this?

Q 2: Has anyone run out of fuel in the left tank and NOT been able to get adequate  fuel flowing from the right  tank?

 

All of this is not new…but the approach to final with little fuel in one tank and lots in the other is scaring the pants off me.

 

Thoughts anyone?

 

Thanks,

Robert 

 

 

Dr. Robert A. Schroeder

Schroeder Fire Inc.

612.922.2349

 

  [quote][b]

CD 2.0

Joined: 21 Feb 2011
Posts: 43

Posted: Sun Jul 24, 2011 2:32 pm Post subject: Re: fuel flow from tanks

Robert, I believe is called uneven wing tank feeding. This tendency has been with the CJ's since discovered on its initial test flight in China. 



As with any aircraft, fuel balance should be closely monitored which you did as you explained. 



The first thing to do is to rectify fuel imbalances using the procedure given in the aircraft flight training manual, namely raise the wing of the tank with the higher level and use crossed controls to attempt to start proper feeding.  I'f I'm correct you tried this and it didn't work. I would also have a mechanic check into this closely.  Thanks for sharing. 



Carl



[quote="Firedog(at)visi.com"]Good morning all,

 

The fuel tank gremlins have struck again.  I need some guidance.

 

Yesterdayâ€™s flight (now 3 days ago):

1983 CJ 6A, no mods to the fuel systemâ€¦straight and level flight, temps in the mid 80â€™s, flying 2-3 thousand feet AGL, (avg elevation 1000 ft.), slight headwind on the nose, 155 lb pilot, no GIB. 

 

No squawks on my outbound flightâ€¦fairly equal fuel usage from both tanks.

I refilled upon arrival at my destinationâ€¦the plane sat for 6 hours in the sun. Only squawk on taxi out was that the right brake was locked upâ€¦a little S turn on the ramp fixed thatâ€¦but let me get to the issue.

 

On my return flight, the left tank was drawn down  to 1.0 on the gauge (16.5 gallon when I later refueled).  The right tank showed between 5 and 6 favoring the 6 (4.0 gallons used).  I tried the shake the plane in flight, crabbing to the right and to a lesser degree tipping my left wing downâ€¦ nothing cured the issue.  I somehow suspect that there is a â€œpilot errorâ€ involved here, I just canâ€™t figure it out.

 

Q 1:  Has anyone else experienced this?

Q 2: Has anyone run out of fuel in the left tank and NOT been able to get adequate  fuel flowing from the right  tank?

 

All of this is not newâ€¦but the approach to final with little fuel in one tank and lots in the other is scaring the pants off me.

 

Thoughts anyone?

 

Thanks,

Robert 

 

 

Dr. Robert A. Schroeder

Schroeder Fire Inc.

612.922.2349

 

   	  Quote: 	
		  [b]

Firedog(at)visi.com
Guest

Posted: Sun Jul 24, 2011 4:11 pm Post subject: fuel flow from tanks

Thanks for the fast response...I may not have been as aggressive nor attached the problem early enough (my reference to pilot error).

Will give the corrective measures a try tomorrow am on my way to OSH.



ras



--

CD 2.0

Joined: 21 Feb 2011
Posts: 43

Posted: Sun Jul 24, 2011 5:13 pm Post subject: Re: fuel flow from tanks

check if the aircraft is out of rig, will not fly in a straight line at normal cruise speed without rudder or aileron input, this will cause fuel in one tank to be pushed towards the fuel pickup point with more force than fuel from the other tank, thus creating a greater fuel tank head pressure in one tank leading to uneven fuel flow. 



Fuel line restrictions. They are rarely the cause of uneven fuel feed, but it can occur. If a fuel line becomes crimped or itâ€™s routing changed, then it can offer more resistance to flow than the line from the other tank. 

Enjoy OSH,

Carl



 	  Firedog(at)visi.com wrote: 	
		  Thanks for the fast response...I may not have been as aggressive nor attached the problem early enough (my reference to pilot error).

Will give the corrective measures a try tomorrow am on my way to OSH.



ras



--

cd001633(at)mindspring.co
Guest

Posted: Sun Jul 24, 2011 6:50 pm Post subject: fuel flow from tanks

Robert,



In most cases, the uneven fuel feed can be corrected by raising the heavier(fuller tank) wing and cross control a little - in my CJ I found that this works BUT it does take a few looong minutes to show on the gage.  Raising the heavy wing a few degrees coupled with cross controlling helps "convince" the inline check-valve to open and start feeding the header tank.  



I have heard (not recently) of a case that the engine did quit after emptying the tank it was feeding from while the other tank was full.  Learning how to cross feed in the air in the CJ is an important procedure to master...



Sam Sax 

Miami, FL

--

KingCJ6(at)aol.com
Guest

Posted: Sun Jul 24, 2011 7:20 pm Post subject: fuel flow from tanks

Robert â€“ this is a problem that has  been the subject of numerous posts on this forum over the years.  Suggested solutions have included  precisely insuring exact rigging, vented fuel caps, different placement or angle  of the vent tubes, proper pilot technique etc..  Several of us have had success with Bill  Blackwellâ€™s mechanical fuel tank vent shut-off kit.  It allows the pilot to simply flip a  mechanical switch to stop venting form the fuller tank until normal fuel feeding  is resumed â€“ usually 5-10 minutes. 

  

Dave

  

 [quote="Firedog(at)visi.com"]Good morning all,



The fuel tank  gremlins have struck again.  I need some guidance.



YesterdayÃ¢â‚¬â„¢s  flight (now 3 days ago):

1983 CJ 6A, no mods to the fuel systemÃ¢â‚¬Â¦straight  and level flight, temps in the mid 80Ã¢â‚¬â„¢s, flying 2-3 thousand feet AGL, (avg  elevation 1000 ft.), slight headwind on the nose, 155 lb pilot, no GIB.  



No squawks on my outbound flightÃ¢â‚¬Â¦fairly equal fuel usage from both  tanks.

I refilled upon arrival at my destinationÃ¢â‚¬Â¦the plane sat for 6 hours  in the sun. Only squawk on taxi out was that the right brake was locked upÃ¢â‚¬Â¦a  little S turn on the ramp fixed thatÃ¢â‚¬Â¦but let me get to the issue.



On my  return flight, the left tank was drawn down  to 1.0 on the gauge (16.5  gallon when I later refueled).  The right tank showed between 5 and 6  favoring the 6 (4.0 gallons used).  I tried the shake the plane in flight,  crabbing to the right and to a lesser degree tipping my left wing downÃ¢â‚¬Â¦  nothing cured the issue.  I somehow suspect that there is a Ã¢â‚¬Å“pilot  errorÃ¢â‚¬Â involved here, I just canÃ¢â‚¬â„¢t figure it out.



Q 1:  Has  anyone else experienced this?

Q 2: Has anyone run out of fuel in the left  tank and NOT been able to get adequate  fuel flowing from the right   tank?



All of this is not newÃ¢â‚¬Â¦but the approach to final with little fuel  in one tank and lots in the other is scaring the pants off me.



Thoughts  anyone?



Thanks,

Robert 

Dr. Robert A.  Schroeder

Schroeder Fire Inc.

612.922.2349



  

 	  Quote: 	
		    [b]


	






Read this topic online  here:



http://forums.matronics.com/viewtopic.php?p=347603#347603

========================  es such  wse,  ;   -->  ================================================             - MATRONICS WEB FORUMS -



  [quote][b]

Adrian Coop Cooper

Joined: 02 Feb 2010
Posts: 37
Location: Vancouver, BC

Posted: Sun Jul 24, 2011 7:57 pm Post subject: Re: fuel flow from tanks

Hi there.

I had a problem where regardless of what I did, I could not get the Right tank down past 19 litres on the gauge. We checked this on the ground and sure enough we could not empty the right tank past this amount, while we could completely drain the left tank. Following Walt Lannon's instructions, we unhooked the vent lines and blew hot soapy water through. The trick is to hold Muslin over the vents into the header tank and see what you can trap.

We were able to dislodge a petrified (as in fossilized, not scared) Lady Bug. Turns out that the shell would act as a valve, occasionally allowing flow but not at other times. Please note, You must use hot soapy water, solvents do not work in this situation. We suspect that the insect was caught up in the U-turn vent in the cockpit ... we don't know if it was a Chinese or a Canadian Lady Bug as the machine had sat unassembled at the airport for a while. 

Also, you might want to contact Walt and talk to him about the flapper valves in the header tank. 

Further, with your CJ on the ground, on level surface with the tires correctly inflated, make sure the inclinometer ball is in the middle. If not re-centre the Turn and Bank and the Gyro. That way, with proper rigging you know you are flying straight and level and the fuel should feed close to evenly.

And yes, I know of a Dromedar (Camel) Russian spray plane (similar system) that did run out of gas, here in Canada ,and crashed because of uneven fuel feed.

Good luck.   Coop.

_________________
Coop

brian(at)lloyd.com
Guest

Posted: Sun Jul 24, 2011 8:50 pm Post subject: fuel flow from tanks

On Sun, Jul 24, 2011 at 8:17 PM, <KingCJ6(at)aol.com> wrote:



[quote] **



 Robert – this is a problem that has been the subject of numerous posts on

 this forum over the years.  Suggested solutions have included precisely

 insuring exact rigging, vented fuel caps, different placement or angle of

 the vent tubes, proper pilot technique etc..  Several of us have had

 success with Bill Blackwell’s mechanical fuel tank vent shut-off kit.  It

 allows the pilot to simply flip a mechanical switch to stop venting form the

 fuller tank until normal fuel feeding is resumed – usually 5-10 minutes

wlannon(at)persona.ca
Guest

Posted: Sun Jul 24, 2011 9:00 pm Post subject: fuel flow from tanks

Robert;

  

 To answer your questions  -----------------

 1.  Yes,  many if not all CJ  pilots.

 2.  Yes,  the most recent I can recall  was in South Africa about 3 years ago.

  

 There are some design features of the CJ fuel and  vent system that contribute to this problem.

 The fuel and vent lines are of different lengths as  the feed tank and the single point vent inlet are not centrally  mounted.   This results in a small decrease in fuel flow from and  vent air flow to the RH tank.

 By itself this is not a major problem as, given all  other features being equal and optimal,  would result in about a 10 to  15 litre imbalance.  

  

 However, there is another design flaw that, in  combination with a less than optimal vent flow system, could result in the "out  of gas with lots in the RH tank" scenario. 

  

 But first the condition of the fuel and vent  system.  All these lines must be scrupulously clean internally, must  be free of any dents, kinks or too tight bends and all connecting hoses must be  in perfect condition with absolutely minimum curvature - preferably  none.

 The aircraft should be leveled on the jacks (using  a level on the lower center section front spar area) and all inclinometer  balls (T&B and Horiz.) exactly centered in the panels.

  

 If you can guarantee all of the above I can  modify your header tank flapper valves (which are the primary problem) and give  you a maximum imbalance of  15 litres - usually much less. 

  

 Contact me off line if you are  interested.

  

 Walt

  

  

  

 [quote]   ---

CD 2.0

Joined: 21 Feb 2011
Posts: 43

Posted: Sun Jul 24, 2011 9:46 pm Post subject: Re: fuel flow from tanks

...this is not a bad deal keeping in mind that while uneven fuel feed can be minimized to some extent by proper maintenance and adjustment, it can never be totally eliminated without some major modifications to the fuel system.



Carl



[quote="wlannon(at)persona.ca"]

  

 If you can guarantee all of the above I can  modify your header tank flapper valves (which are the primary problem) and give  you a maximum imbalance of  15 litres - usually much less. 

  

 Contact me off line if you are  interested.

  

 Walt

  

  	  Quote: 	
		     ---

Firedog(at)visi.com
Guest

Posted: Mon Jul 25, 2011 2:07 am Post subject: Fuel flow from tanks

Thank you all,

 

I will be more attuned to the fuel usage and lift that heavy wing up.  Kelley Monroe and I will recheck the vent line later this week.

Your guidance will no doubt result in happier less stressed pilot!

Off to OSH… 

 

ras

 

Dr. Robert A. Schroeder

Schroeder Fire Inc.

612.922.2349

 

  [quote][b]

brian(at)lloyd.com
Guest

Posted: Mon Jul 25, 2011 8:07 am Post subject: Fuel flow from tanks

On Mon, Jul 25, 2011 at 3:04 AM, Dr. Robert Schroeder <Firedog(at)visi.com (Firedog(at)visi.com)> wrote:

 	  Quote: 	
		   

Thank you all,

 

I will be more attuned to the fuel usage and lift that heavy wing up.  Kelley Monroe and I will recheck the vent line later this week. 

Your guidance will no doubt result in happier less stressed pilot!



	




I can attest to the fact that landing with the engine still running is far less stressful than landing with the engine not running.

 



Have fun at OSH guys!



-- 

Brian Lloyd, WB6RQN/J79BPL

3191 Western Dr.

Cameron Park, CA 95682

brian(at)lloyd.com (brian(at)lloyd.com)

 +1.767.617.1365 (Dominica)

+1.916.877.5067 (USA)



  [quote][b]

Rob Rowe

Joined: 10 Jan 2006
Posts: 124
Location: Berkshire, UK

Posted: Mon Jul 25, 2011 11:44 am Post subject: Re: fuel flow from tanks

Robert,



FWIW on YAK-52s I've found the following are the most common causes of fuel imbalance ... many I expect will be common to CJs too.



- prolonged orbits or circuits in one direction

- flown with slip ball out of balance (high tank feeds, low tank receives more overflow)

- slip gauge incorrectly aligned or aircraft rigged out of trim

- feed check valve install orientation can impact fuel flow preference or may be contaminated (sticking)

- fuel caps seals stretched (from prolonged over-tightening : tank pressure drops to above wing pressure reducing feed/increasing return fuel)

- vents blocked by debris or insects

- aircraft with individual tank vents ... outlets not equally aligned with slipstream

- vent/fuel pipes dented/kinked



Subtle changes can create big imbalance situations â€“ the devilâ€™s in the detail!



If you've suddenly experienced a fuel imbalance problem then a simple check is to exchange the fuel caps to see if one of their seals has stretched  ... if the problem swap sides you'll have localised the problem.



Cheers, Rob R

dsavarese0812(at)bellsout
Guest

Posted: Mon Jul 25, 2011 12:35 pm Post subject: fuel flow from tanks

One factor not mentioned is and especially with the single vent tube Yak 

52's, when the fuel tanks are full and the airplane sits on the ramp in 

the hot sun, the fuel expands and the ONLY 2 places place it can expand 

to is into the vent line and into the header tank which can expand into 

the vent system as well. Once the fuel enters the vent line, the tank 

with the fuel-blocked vent line will not feed properly. The tell-tale 

sign is fuel venting out of the belly vent line while sitting on the 

ramp in the hot sun.



Ever open a fuel tank cap and have the fuel gush out onto the wing? You 

can go to the bank the vent line is full of fuel.



The best thing a person can do when this happens is to blow the vent 

system for each tank individually by opening one cap at a time, 

connecting a piece of hose on the vent tube exiting from the belly and 

blow back through the vent. This will in most cases push the fuel in the 

vent line back into the tank. You may also push more fuel out of the 

fuel cap as well. Then cap the tank and move to the other tank and do 

the same thing.



There is one exception to this though. If the header tank vent tube LOOP 

is not far enough above the junction where all the vent lines come 

together, the header tank fuel vent will continue to fill the right tank 

vent line because it is the lower than the right tank vent line where it 

attaches to the vent junction (on the 52). So be sure to check the vent 

loop from the header tank to the vent junction and make sure the loop is 

going well above the floor in the rear cockpit (where the header tank is 

installed).



Dennis



A. Dennis Savarese

334-285-6263

334-546-8182 (cell)

Skype: Yakguy1

www.yak-52.com

On 7/25/2011 2:44 PM, Rob Rowe wrote:

 	  Quote: 	
		   



 Robert,



 FWIW on YAK-52s I've found the following are the most common causes of fuel imbalance ... many I expect will be common to CJs too.



 - prolonged orbits or circuits in one direction

 - flown with slip ball out of balance (high tank feeds, low tank receives more overflow)

 - slip gauge incorrectly aligned or aircraft rigged out of trim

 - feed check valve install orientation can impact fuel flow preference or may be contaminated (sticking)

 - fuel caps seals stretched (from prolonged over-tightening : tank pressure drops to above wing pressure reducing feed/increasing return fuel)

 - vents blocked by debris or insects

 - aircraft with individual tank vents ... outlets not equally aligned with slipstream

 - vent/fuel pipes dented/kinked



 Subtle changes can create big imbalance situations â€“ the devilâ€™s in the detail!



 If you've suddenly experienced a fuel imbalance problem then a simple check is to exchange the fuel caps to see if one of their seals has stretched  ... if the problem swap sides you'll have localised the problem.



 Cheers, Rob R





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=347676#347676

Rob Rowe

Joined: 10 Jan 2006
Posts: 124
Location: Berkshire, UK

Posted: Mon Jul 25, 2011 5:35 pm Post subject: Re: fuel flow from tanks

Good point Dennis ... had not included it as I gathered the SOP on single vent YAK-52s was not to brim full tanks to avoid vent feed issue & in extremis expansion overflow from vent creating a siphoning effect. Addressed by the separate tank vents introduced from mid-1989+ production aircraft ... albeit in doing so creating further variables that can impact fuel imbalance.



Also my understanding was that this was primarily a ground issue (other than the header tank loop exception mentioned) and that once the engine was started and a few litres consumed the common vent/return lines (single belly vent aircraft) to each tank would no longer be fuel-blocked. Have I missed something here?



However it does give me pause for further thought on how the separately vented tank aircraft (mid-1989+) might be impacted by expansion fuel trapped in the vent lines as these would not be cleared post engine start given this design has given them individual vent loops now independent of the fuel return lines. As the tank belly vents are angled into the airflow the positive pressure in-flight, coupled with a slight additional pressure drop (beyond that created by fuel usage) in the fuel trapped vent tank, suggests that any trapped vent fuel would be brought back into the tank. Conjecture on my part ... what do you think?



Thanks, Rob



On 7/25/2011 8:35 PM, Dennis Savarese wrote:

 	  Quote: 	
		  One factor not mentioned is  ....

dsavarese0812(at)bellsout
Guest

Posted: Tue Jul 26, 2011 6:20 am Post subject: fuel flow from tanks

Robb,

Regarding, "once the engine was started and a few litres consumed the 

common vent/return lines (single belly vent aircraft) to each tank would 

no longer be fuel-blocked. Have I missed something here?".  Yes, 

possibly.  The culprit is the position of the vent junction in relation 

to the RIGHT tank vent line and the header tank vent line.



If the vent junction (the cross on the left side of the front seat) sits 

just a bit below the top of the header tank and the header tank vent 

tube loop which typically is connected to the bottom of the T, the 

header tank vent line will fill the vent T and thus force fuel into the 

right tank vent line.  The right tank vent line enters the vent T at the 

rear of the T.  The overboard vent loop comes off the front of the T and 

goes forward toward the firewall and has a huge loop in it that loops 

down and back through the belly just below the front seat.   If the 

tanks are filled to the brim and the airplane is out in the sun, the 

expansion goes into all the vent lines.  In addition, the expansion of 

the fuel pushes the fuel through the fuel junction below the front seat 

where the flapper valves are and into the header tank.  Most of the time 

the header tank is about full anyway.  The expansion pushes more fuel 

into the header tank and out the header tank vent line into the vent T.  

Now we have set up the opportunity for siphoning.  This continued 

expansion pushes the fuel out through all of the vent lines and out the 

only open port which is the vent loop going to the belly.



The left tank vent line which going up from the top of the T is 

typically not an issue because the vent line is above all the other vent 

connections and fuel runs out of it pretty well.  This is not true of 

the right tank.  It lies basically flat across the front of the main 

spar.  So the fuel is held captive in it.  To compound the problem, if 

TOP the header tank vent line (ie: the loop) is below the top of the 

header tank, fuel runs out of the header vent into the bottom of the 

vent T pushing fuel into the right tank vent line.  I have probably seen 

this at least 8-10 times.



Bottom line here is if a person is having problems with fuel feeding 

AFTER they have checked the rigging of the airplane, disconnect the line 

at the rear of the vent T, which is from the right tank.  If when you 

remove the B nut fuel runs out of the line, you know where the problem 

is.  Start by increasing the loop height from the header vent line so it 

is over or at least to the top of the main spar.  You may have to make a 

new line or add a flexible hose to create the loop.



Don't forget to loosen your fuel caps after the airplane has sat out in 

the sun for a bit.  Particularly if it has over 45 liters in each tank.  

Then blow the vent lines out as previously explained.

Dennis



A. Dennis Savarese

334-285-6263

334-546-8182 (cell)

Skype: Yakguy1

www.yak-52.com

On 7/25/2011 8:35 PM, Rob Rowe wrote:

 	  Quote: 	
		   



 Good point Dennis ... had not included it as I gathered the SOP on single vent YAK-52s was not to brim full tanks to avoid vent feed issue&  in extremis expansion overflow from vent creating a siphoning effect. Addressed by the separate tank vents introduced from mid-1989+ production aircraft ... albeit in doing so creating further variables that can impact fuel imbalance.



 Also my understanding was that this was primarily a ground issue (other than the header tank loop exception mentioned) and that once the engine was started and a few litres consumed the common vent/return lines (single belly vent aircraft) to each tank would no longer be fuel-blocked. Have I missed something here?



 However it does give me pause for further thought on how the separately vented tank aircraft (mid-1989+) might be impacted by expansion fuel trapped in the vent lines as these would not be cleared post engine start given this design has given them individual vent loops now independent of the fuel return lines. As the tank belly vents are angled into the airflow the positive pressure in-flight, coupled with a slight additional pressure drop (beyond that created by fuel usage) in the fuel trapped vent tank, suggests that any trapped vent fuel would be brought back into the tank. Conjecture on my part ... what do you think?



 Thanks, Rob



 On 7/25/2011 8:35 PM, Dennis Savarese wrote:



> One factor not mentioned is  ....





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=347708#347708

keithmckinley

Joined: 11 Aug 2008
Posts: 434

Posted: Tue Jul 26, 2011 10:53 am Post subject: Re: fuel flow from tanks

For what it's worth:



1. Flying in a true wings level crab will do nothing. 

2. As mentioned, the high tank wing needs to be higher and at least initially, significantly.

3. A centered ball does not mean coordinated flight. Use the rudder to level the wings and note the ball position for reference.

4. When rechecking the gauge you absolutely must have the wings leveled in      coordinated flight or the gauge is not accurate (again with the rudder to level wings)

5. I believe that there is a slight amount of null in my gauges from them being mostly in the mid range for so much of their life. Therefore the gauge is just a tad unreliable there.

6. I WOULD NOT RUN A TANK DRY! There is no guarantee the other tank will feed

7. It's Not too hard to pull the header tank and check the flapper valves.

8. FF gage helps immensely. worth the $$ to install.



Last but not least, this issue certainly increases our fuel awareness, which is a good thing!



Semper Fi

brian(at)lloyd.com
Guest

Posted: Tue Jul 26, 2011 11:56 am Post subject: fuel flow from tanks

On Tue, Jul 26, 2011 at 11:53 AM, keithmckinley <keith.mckinley(at)townisp.com (keith.mckinley(at)townisp.com)> wrote:

 	  Quote: 	
		   --> Yak-List message posted by: "keithmckinley" <keith.mckinley(at)townisp.com (keith.mckinley(at)townisp.com)>

 

 For what it's worth:

 

 1. Flying in a true wings level crab will do nothing.

	




Flying in a wings-level crab isn't possible. The result would be a skidding turn with the ball deflected to the outside of the turn. BTW, this would favor fuel flow from the tank on the inside of the turn.

  

 	  Quote: 	
		   2. As mentioned, the high tank wing needs to be higher and at least initially, significantly.

	




"High wing," is equally meaningless. The only meaningful issue in terms of flight control to effect relative fuel flow from the tanks deflection of the ball.

 



 	  Quote: 	
		  3. A centered ball does not mean coordinated flight. Use the rudder to level the wings and note the ball position for reference.

 	




Yes, a centered ball DOES mean coordinated flight. Of course, that does presume that the ball has been properly calibrated on the ground with the airframe leveled laterally. But once the ball has been calibrated, centering the ball means coordinated flight.

  

 	  Quote: 	
		   4. When rechecking the gauge you absolutely must have the wings leveled in coordinated flight or the gauge is not accurate (again with the rudder to level wings)

	




No. When checking the gauge you absolutely must have the BALL CENTERED. It doesn't matter if you are turning or not.

  

 	  Quote: 	
		   5. I believe that there is a slight amount of null in my gauges from them being mostly in the mid range for so much of their life. Therefore the gauge is just a tad unreliable there.

	




Could be. 

  

 	  Quote: 	
		   6. I WOULD NOT RUN A TANK DRY! There is no guarantee the other tank will feed

	




If your fuel system is working properly you should not be able to run a tank dry. Conversely, if you CAN run a tank dry you need to spend some time working on your fuel system.

 



 	  Quote: 	
		   7. It's Not too hard to pull the header tank and check the flapper valves.

 8. FF gage helps immensely. worth the $$ to install.

	




I agree with both of these. 

 

 	  Quote: 	
		    

 Last but not least, this issue certainly increases our fuel awareness, which is a good thing!

	




I agree with that too.



-- 

Brian Lloyd, WB6RQN/J79BPL

3191 Western Dr.

 Cameron Park, CA 95682

brian(at)lloyd.com (brian(at)lloyd.com)

+1.767.617.1365 (Dominica)

+1.916.877.5067 (USA)



  [quote][b]

keithmckinley

Joined: 11 Aug 2008
Posts: 434

Posted: Tue Jul 26, 2011 1:25 pm Post subject: Re: fuel flow from tanks

Why didn't I expect to get nickled and dimed on this board. 



But here goes Brian. Yes a pure crab with wings level is possible but then again in my 1000+ hours in the AV8B Harrier I probably wasn't paying attention. And by the way seems like I have neutral ailerons crabbed into a x-wind and I'm talking big picture not mm



high wing on high tank isn't meaningless but I know what you mean, high wing while maintaining course/heading will obviously kick the ball out.



again if your instrument is off a centered ball is less important than level wings when checking gauges. wings should be level with a centered ball but only if it adjusted correctly. I can guarantee that my gauge is never correct in a turn. centered ball or not.



Incidentally, my presumption was (unstated) that most guys are flying around with misaligned or defective slip indicators. Additionally, We'd also have to presume the ailerons are rigged correctly.



I have used these techniques right or wrong for 3 years and land every time with no more than a 5-10 liter imbalance.

 

I guess I'm still just a seat of the pants guy. Thanks for setting me straight.



Regards

brian(at)lloyd.com
Guest

Posted: Tue Jul 26, 2011 2:11 pm Post subject: fuel flow from tanks

On Tue, Jul 26, 2011 at 2:25 PM, keithmckinley <keith.mckinley(at)townisp.com (keith.mckinley(at)townisp.com)> wrote:

 	  Quote: 	
		   --> Yak-List message posted by: "keithmckinley" <keith.mckinley(at)townisp.com (keith.mckinley(at)townisp.com)>

 

 Why didn't I expect to get nickled and dimed on this board.

	




When you endeavor to teach something, it is best to be sure of your material. In my tenure as a teacher I discovered that the most important response I could ever make to a student was, "You know, I am not sure. Let's find out."

 



I am quite certain you are more than qualified to fly the Harrier. No doubt you can do that far better than I can. But being able to fly the Harrier does not necessarily convey full understanding the forces involved in the flight of a standard aircraft. There are lots of people who successfully herd airplanes around the sky or cars on the road who do not fully understand why they do exactly what they do. Still, they are successful at getting where they want to go. So this is not an attempt to put you down, only to provide more correct information.

 



I am prepared to respond to your points but it will only be worthwhile if you (and others) are interested.

-- 

Brian Lloyd, WB6RQN/J79BPL

3191 Western Dr.

Cameron Park, CA 95682

 brian(at)lloyd.com (brian(at)lloyd.com)

+1.767.617.1365 (Dominica)

+1.916.877.5067 (USA)



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