REFLECTOR: Uneven Fuel Flow

Robert Wood slvegl99 at aol.com
Thu Sep 29 14:02:23 CDT 2011 

My vent system has a check valve which will allow air inflow if he vent is plugged. The valve is located behind the rear seat, mounted to the bulkhead.

Bob Wood
Sent from my iPad

On Sep 29, 2011, at 2:56 PM, Jim Agnew <jim_agnew_2 at yahoo.com> wrote:

> You should also drill a small hole on the back side of the vent tube a little above the cut off in case something plugs the front side so you will still get some venting 1/8" is fine.
>  
> Jim
>  
> James F. Agnew
> Jim_Agnew_2 at Yahoo.Com
> Tampa, FL
> Velocity 173 Elite Aircraft Completed & Flying
> 
> From: John Abraham <john at velocityaircraft.com>
> To: 'Velocity Aircraft Owners and Builders list' <reflector at tvbf.org>
> Sent: Thursday, September 29, 2011 2:19 PM
> Subject: Re: REFLECTOR: Uneven Fuel Flow
> Your vent should be cut at a 45 degree angle with the point facing backwards (prop).  This allows air to ram into the vent.
>  
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Juanita Londenberg
> Sent: Thursday, September 29, 2011 1:50 PM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Uneven Fuel Flow
>  
> When you say " If you were to cut your
> vent flat or scarf it backwards" --  what is the correct orientation of the vent?
> 
> Juanita
> 
> --- On Thu, 9/29/11, John Abraham <john at velocityaircraft.com> wrote:
> 
> From: John Abraham <john at velocityaircraft.com>
> Subject: Re: REFLECTOR: Uneven Fuel Flow
> To: "'Velocity Aircraft Owners and Builders list'" <reflector at tvbf.org>
> Date: Thursday, September 29, 2011, 9:36 AM
> Above the fuel cap is a low pressure.  This creates a vacuum on the tank if
> the cap is loose.  If it is loose enough you will see fuel coming out of the
> tank.  Have you ever flown a piper when a fuel cap came off on take-off?  An
> entire tank will be sucked out in a matter of a minute or so.  Your fuel
> vent line is pressurizing the tank with ram air.  If you were to cut your
> vent flat or scarf it backwards then you can also create a vacuum on the
> tank that will not let the tanks feed very well.
> 
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Jones Nick
> Sent: Thursday, September 29, 2011 10:16 AM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Uneven Fuel Flow
> 
> I'm with you on this one. I hope someone can explain this.
> 
> Nick Jones
> XL-RG
> N10CN
> 
> 
> ________________________________
> From: reflector-bounces at tvbf.org [reflector-bounces at tvbf.org] On Behalf Of
> Brooke Wolf [bwolf1 at tds.net]
> Sent: Thursday, September 29, 2011 09:41
> To: reflector at tvbf.org
> Subject: REFLECTOR: Uneven Fuel Flow
> 
> 
> 
> Ok, at the risk of showing my ignorance, I need to chime in here.
> 
> How could a minute leak in a fuel cap affect fuel flow out of a tank when
> that same tank has about a 3/8 inch hole in it vented to the outside (aka
> fuel vents)?
> 
> Brooke
> 
> 
> 
> 
> From: "John Abraham"
> <john at velocityaircraft.com<mailto:john at velocityaircraft.com>>
> Date: September 29, 2011 8:06:09 AM EDT
> To: "'Velocity Aircraft Owners and Builders list'"
> <reflector at tvbf.org<mailto:reflector at tvbf.org>>
> Subject: Re: REFLECTOR: Reflector Digest, Vol 78, Issue 80 Uneven fuel flow
> Reply-To: Velocity Aircraft Owners and Builders list
> <reflector at tvbf.org<mailto:reflector at tvbf.org>>
> 
> 
> Just an additional note to what Mark said.  If you have uneven fuel flow,
> you should also check the lip of the fuel ring on your tank.  When you fill
> up your tank or have an FBO do this for you if they hit the ring hard enough
> with the nozzle and either dent it or score it your cap will also not close
> properly.
> 
> 5-7 gallons different per side is acceptable.  The tanks are fighting each
> other by gravity pressure.  Also as a result of this if you are slightly out
> of rig; even half a ball, over the course of 2-3 hours on a trip you will
> have uneven feeding.  More than half a tank difference is unacceptable and
> you need to land to see what is going on with your system.  You do not want
> to wait until you are down to 3 gallons on one side while you have a full
> tank on the other side anticipating for it to feed.
> 
> You also want to make sure that your low fuel warning light works.  You can
> test it in flight without draining your tanks down.  Sometimes when you hit
> turbulence it will flash the light on and off a few times.  Also, if you
> stomp on the rudders back and forth 2-3 times it will make the switch
> trigger, flash the light and go out.
> 
> Safe flying,
> 
> John
> 
> -----Original Message-----
> From: reflector-bounces at tvbf.org<mailto:reflector-bounces at tvbf.org>
> [mailto:reflector-bounces at tvbf.org] On Behalf Of Mark Riley
> Sent: Wednesday, September 28, 2011 8:56 PM
> To: reflector at tvbf.org<mailto:reflector at tvbf.org>
> Subject: Re: REFLECTOR: Reflector Digest, Vol 78, Issue 80 Uneven fuel flow
> 
> On my XL I had uneven fuel flow and asked Duane Swing to take a look when we
> stopped in Sebastian on the way to the Bahamas. He noticed two problems I
> never would have caught. The O rings on the filler cap had minute flecks of
> primer paint on them, which prevented them from creating an airtight seal.
> Andy Millin and I spent an hour picking it off with our fingernails then
> greasing them up with fuel lube. He also noticed that the gap around the
> filler caps was too tight, so that it prevented the cap on one side from
> seating properly. We just sanded it back ever so slightly until the cap
> didn't rock at all when latched shut. If you try these fixes and still
> wonder about your caps, you can try covering them with duct tape. Even a
> minute problem like I've described can cause uneven drainage from the tanks
> even in a properly rigged plane.
> 
> Two more thoughts - first, it is not uncommon for the tanks to drain
> unevenly but catch up to each other. One of my tanks always drains faster
> between about 25 and 17 gallons, then the other one catches up. Second, if
> the tanks get uneven, you can simply slip the plane for 1-2 minutes with the
> uneven tank up. I find that they then drain evenly. I tried this for the
> first time 100 miles from the nearest land on my way back to pick up the
> Millins. Probably better to try it in a more comfortable setting first.
> 
> Hope that helps.
> 
> Mark
> On Sep 28, 2011, at 8:32 PM,
> reflector-request at tvbf.org<mailto:reflector-request at tvbf.org> wrote:
> 
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> 
> 
> Today's Topics:
> 
> 1. Re:  STD RG Trim (Scott Derrick)
> 2. Re:  STD RG Trim (Glenn Babcock)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Wed, 28 Sep 2011 17:05:12 -0700
> From: Scott Derrick <scott at tnstaafl.net<mailto:scott at tnstaafl.net>>
> Subject: Re: REFLECTOR: STD RG Trim
> To: Velocity Aircraft Owners and Builders list
> <reflector at tvbf.org<mailto:reflector at tvbf.org>>
> Message-ID:
> <050fue2q67u5ay5mcgjyf6a6.1317254691797 at email.android.com<mailto:050fue2q67u
> 5ay5mcgjyf6a6.1317254691797 at email.android.com>>
> Content-Type: text/plain; charset="utf-8"
> 
> The unequal fuel born is because of the miss adjusted rudder trim.  The fuel
> is acting as a really big BALL and is moving with the litttle ball.
> 
> Glenn Babcock
> <glennbabcock at roadrunner.com<mailto:glennbabcock at roadrunner.com>> wrote:
> 
> Izzy,
> 
> Here's what I did:
> 
> - On the ground, level the plane.  Use a rotary laser level to level the
> wings left to right, you can get one for under $100.  Put sawhorses or
> something under the wings to hold the position.  Also level the plane front
> to back.
> - Verify that the wing incidence is correct for both wings using the
> incidence gauge.  While you're at it verify the canard incidence.
> - Verify the strake leading edge position on both sides.
> - If needed, shim the wings and/or canard.  If the strakes are out that's a
> more complicated fix!
> - Now check that the TC is level (mine wasn't, making the problem look worse
> than it was).  The ball should be right in the center.
> - If you made no corrections in the wings or canard, shim the rudder (if you
> made corrections, test fly first to see if it's still out).  I found that
> you can hot glue bits of tongue depressor at the top, middle and bottom of
> the rudder then trim them down as needed.  A small amount of shim makes a
> big difference!  Make sure that the rudder touches all three shims when it's
> resting.
> - Also check the opposite rudder, you may be able to trim a SMALL amount off
> of that side.
> - Once you have the correct amount of shim, fill the gap with epoxy mixed
> with micro glass or flox, then after it cures sand it till it's neat.  It's
> very easy to do.
> 
> The fuel not draining evenly may be due to a leaking fuel cap.  Remove the
> cap and coat the O-rings with Fuelube.  Make sure you get the little one on
> the stem as well as the big one on the rim.
> 
> Regards,
> Glenn
> 
> 
> On Sep 28, 2011, at 9:06 AM, Dugas Bellsouth wrote:
> 
> I did the same only used 1/16" angle aluminum. I trimmed a 1.5" so when
> placed inside of the winglet it was flush with the airflow surface on the
> fuselage side of the winglet. I the epoxied it to the inside of the winglet
> and flew. Worked great. Still there and did not require all the glass work.
> 
> Rene' Dugas
> Sent from my iPhone4
> 
> On Sep 27, 2011, at 5:56 PM, Scott Derrick
> <scott at tnstaafl.net<mailto:scott at tnstaafl.net>> wrote:
> 
> Trim the left rudder out until the ball is in the center.
> 
> Tape the vertical with duct tape near the lower part of the rudder.
> Place a shim between the rudder and the vertical, about an 1/8 inch thick.
> Then fill the gap with micro or epoxy glue, about 2 inches long, so it
> sticks to the rudder.  Let cure, clean it up and fly. If that was to much
> file the new tab down a bit and test fly again.  If the ball is still out,
> add another 1/8 inch and test fly.  Do this until the ball is in the center.
> 
> 
> Once you have the ball in the center, yaw trim, you can evaluate the
> roll trim.   If the plane still wants to roll and the roll trim cannot
> handle that you can shim both or one wing.  You usually want to shim the
> light wing first by taking some of the aoa out of that wing by shimming the
> lower bolt. If thta s not enough add in more aoa to the heavy wing by
> shimming the upper bolts.
> 
> Scott
> 
> Izzy Brownfield <iznstacy at yahoo.com<mailto:iznstacy at yahoo.com>> wrote:
> 
> I'm a new owner of a STD RG with io-360 three blade MT prop At cruise T&B
> indicator is half ball to the left with a slight left turn tendency. Fuel is
> consumed from the right tank at twice the rate of the left tank.
> To center the ball it requires quite a bit of left rudder and light right
> aileron pressure.
> What adjustment is needed to be made to correct this?
> Thanks
> Izzy
> 5txo
> 
> Sent from my iPhone
> _______________________________________________
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> ------------------------------
> 
> Message: 2
> Date: Wed, 28 Sep 2011 19:32:42 -0500
> From: Glenn Babcock
> <glennbabcock at roadrunner.com<mailto:glennbabcock at roadrunner.com>>
> Subject: Re: REFLECTOR: STD RG Trim
> To: Velocity Aircraft Owners and Builders list
> <reflector at tvbf.org<mailto:reflector at tvbf.org>>
> Message-ID:
> <F71FDCA0-9D0C-4A13-88A1-B6991DFA73A4 at roadrunner.com<mailto:F71FDCA0-9D0C-4A
> 13-88A1-B6991DFA73A4 at roadrunner.com>>
> Content-Type: text/plain; charset="us-ascii"
> 
> It may be that or it may not, or it may be both.  I know that many people
> have chased fuel flow problems all around the aircraft only to find the fuel
> caps were leaking, causing a drop in pressure in one tank and restricting
> fuel flow on that side.  A tiny amount of Fuelube and about 5 minutes effort
> and the problem is solved.
> 
> Regards,
> Glenn
> 
> 
> On Sep 28, 2011, at 7:05 PM, Scott Derrick wrote:
> 
> The unequal fuel born is because of the miss adjusted rudder trim. The fuel
> is acting as a really big BALL and is moving with the litttle ball.
> 
> Glenn Babcock
> <glennbabcock at roadrunner.com<mailto:glennbabcock at roadrunner.com>> wrote:
> 
> Izzy,
> 
> Here's what I did:
> 
> - On the ground, level the plane.  Use a rotary laser level to level the
> wings left to right, you can get one for under $100.  Put sawhorses or
> something under the wings to hold the position.  Also level the plane front
> to back.
> - Verify that the wing incidence is correct for both wings using the
> incidence gauge.  While you're at it verify the canard incidence.
> - Verify the strake leading edge position on both sides.
> - If needed, shim the wings and/or canard.  If the strakes are out that's a
> more complicated fix!
> - Now check that the TC is level (mine wasn't, making the problem look worse
> than it was).  The ball should be right in the center.
> - If you made no corrections in the wings or canard, shim the rudder (if you
> made corrections, test fly first to see if it's still out).  I found that
> you can hot glue bits of tongue depressor at the top, middle and bottom of
> the rudder then trim them down as needed.  A small amount of shim makes a
> big difference!  Make sure that the rudder touches all three shims when it's
> resting.
> - Also check the opposite rudder, you may be able to trim a SMALL amount off
> of that side.
> - Once you have the correct amount of shim, fill the gap with epoxy mixed
> with micro glass or flox, then after it cures sand it till it's neat.  It's
> very easy to do.
> 
> The fuel not draining evenly may be due to a leaking fuel cap.  Remove the
> cap and coat the O-rings with Fuelube.  Make sure you get the little one on
> the stem as well as the big one on the rim.
> 
> Regards,
> Glenn
> 
> 
> On Sep 28, 2011, at 9:06 AM, Dugas Bellsouth wrote:
> 
> I did the same only used 1/16" angle aluminum. I trimmed a 1.5" so when
> placed inside of the winglet it was flush with the airflow surface on the
> fuselage side of the winglet. I the epoxied it to the inside of the winglet
> and flew. Worked great. Still there and did not require all the glass work.
> 
> Rene' Dugas
> Sent from my iPhone4
> 
> On Sep 27, 2011, at 5:56 PM, Scott Derrick
> <scott at tnstaafl.net<mailto:scott at tnstaafl.net>> wrote:
> 
> Trim the left rudder out until the ball is in the center.
> 
> Tape the vertical with duct tape near the lower part of the rudder.
> Place a shim between the rudder and the vertical, about an 1/8 inch thick.
> Then fill the gap with micro or epoxy glue, about 2 inches long, so it
> sticks to the rudder.  Let cure, clean it up and fly. If that was to much
> file the new tab down a bit and test fly again.  If the ball is still out,
> add another 1/8 inch and test fly.  Do this until the ball is in the center.
> 
> 
> Once you have the ball in the center, yaw trim, you can evaluate the
> roll trim.   If the plane still wants to roll and the roll trim cannot
> handle that you can shim both or one wing.  You usually want to shim the
> light wing first by taking some of the aoa out of that wing by shimming the
> lower bolt. If thta s not enough add in more aoa to the heavy wing by
> shimming the upper bolts.
> 
> Scott
> 
> Izzy Brownfield <iznstacy at yahoo.com<mailto:iznstacy at yahoo.com>> wrote:
> 
> I'm a new owner of a STD RG with io-360 three blade MT prop At cruise T&B
> indicator is half ball to the left with a slight left turn tendency. Fuel is
> consumed from the right tank at twice the rate of the left tank.
> To center the ball it requires quite a bit of left rudder and light right
> aileron pressure.
> What adjustment is needed to be made to correct this?
> Thanks
> Izzy
> 5txo
> 
> Sent from my iPhone
> _______________________________________________
> To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
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