Today's Message Index:
----------------------
1. 12:33 AM - Fairings-Etc Reply (bob@fairings-etc.com)
2. 02:11 PM - Fuel Pump Issue (Bob Leffler)
3. 02:46 PM - Re: Fuel Pump Issue (Linn Walters)
4. 03:03 PM - Prop spinner cutouts (Chris Hukill)
5. 03:37 PM - Re: Fuel Pump Issue (Kelly McMullen)
6. 04:05 PM - Re: Fuel Pump Issue (Bob Leffler)
7. 04:10 PM - Re: Fuel Pump Issue (Linn Walters)
8. 04:11 PM - Re: Fuel Pump Issue (speckter@comcast.net)
9. 04:52 PM - Re: Fuel Pump Issue (Carl Froehlich)
10. 05:05 PM - Re: Fuel Pump Issue (Kelly McMullen)
11. 05:54 PM - Re: Fuel Pump Issue (Marcus Cooper)
12. 05:56 PM - Re: Prop spinner cutouts (Chris)
13. 05:59 PM - Re: Prop spinner cutouts (Bob-tcw)
14. 06:05 PM - Re: Fuel Pump Issue (Linn Walters)
Message 1
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| Subject: | Fairings-Etc Reply |
I will be unable to access my computer for a few days. My lady, Sonya, who does
all my computer things for me, will be gone for a few days starting on the 17th.
I will reply to your emails and orders starting on the 21th. If you need to
urgently speak with me directly before that date, please call me on my cell
phone: 623-203-09795.
Bob Snedaker
Fairings-Etc
Message 2
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As several already are aware, I had some fuel flow issues on my first
flight. At the time, in the air, I wasn't quite sure what the issue may
have been. It was initially looking like a blocked fuel line. The symptom
was that the fuel pressure dropped significantly, but came back up with the
electric fuel pump turned on and switching the tanks. I promptly landed and
started looking for the root cause.
1. The left and right tank fuel flow (measured at the firewall,
forward of the filter and pump) was 58 gallons/hour. Rules out a blockage
aft of the firewall.
2. The fuel vents are not obstructed
I ran the engine in a static test. Was getting about 20psi on the engine
fuel pump and about 26psi with the electric fuel pump enabled. Since this
is all within specifications, this is the worst of all the scenarios. No
root cause and everything seems to be working as designed.
This morning I flew for about an hour on flight #2.
When I turned off the electric fuel pump, fuel pressure started to
immediately drop. I let it drop to about 10psi before I re-engaged the
electric fuel pump. With the electric fuel pump running, I was getting
26psi. I repeated this scenario multiple times on both fuel tanks during
the flight. Results were pretty consistent.
It's looking like I may have a bad fuel pump on this 1 SNEW YIO-540-D4A5.
I plan on giving Lycoming a call in the morning.
My questions is there any other scenarios that I'm overlooking that may
yield similar symptoms?
Thanks,
bob
Message 3
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| Subject: | Re: Fuel Pump Issue |
With the info presented I think you're spot on. I agree with the call
to Lycoming .... they should ship you a new pump. Up to you to do the
R&R which has always been a PITA for me. My best guess is that there is
some small piece of trash (don't know what else to call it) hung up in
one of the valves.
Linn
On 10/20/2013 4:47 PM, Bob Leffler wrote:
>
> As several already are aware, I had some fuel flow issues on my first
> flight. At the time, in the air, I wasn't quite sure what the issue
> may have been. It was initially looking like a blocked fuel line.
> The symptom was that the fuel pressure dropped significantly, but came
> back up with the electric fuel pump turned on and switching the
> tanks. I promptly landed and started looking for the root cause.
>
> 1.The left and right tank fuel flow (measured at the firewall, forward
> of the filter and pump) was 58 gallons/hour. Rules out a blockage aft
> of the firewall.
>
> 2.The fuel vents are not obstructed
>
> I ran the engine in a static test. Was getting about 20psi on the
> engine fuel pump and about 26psi with the electric fuel pump enabled.
> Since this is all within specifications, this is the worst of all the
> scenarios. No root cause and everything seems to be working as designed.
>
> This morning I flew for about an hour on flight #2.
>
> When I turned off the electric fuel pump, fuel pressure started to
> immediately drop. I let it drop to about 10psi before I re-engaged
> the electric fuel pump. With the electric fuel pump running, I was
> getting 26psi. I repeated this scenario multiple times on both fuel
> tanks during the flight. Results were pretty consistent.
>
> It's looking like I may have a bad fuel pump on this 1 SNEW
> YIO-540-D4A5. I plan on giving Lycoming a call in the morning.
>
> My questions is there any other scenarios that I'm overlooking that
> may yield similar symptoms?
>
> Thanks,
>
> bob
>
> *
>
>
> *
>
> No virus found in this message.
> Checked by AVG - www.avg.com <http://www.avg.com>
>
Message 4
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| Subject: | Prop spinner cutouts |
I'm trying to determine the optimum cutout dimensions for the blades on
the 2 bladed Hartzell blended airfoil prop as Vans sells, using the
standard spinner kit. The instructions tell you to rotate the blades
thru full travel to check for clearance, however I don't have an engine
to mount the prop to yet, and it's not possible to move the blades
without one. I am trying to get as tight of fit as is possible. I have
looked at production airplane's installations, and they have a much
larger clearance than I would consider aesthetic. Has anyone made a
template or drawings that would provide the dimensions that I need?
Chris Hukill
Message 5
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| Subject: | Re: Fuel Pump Issue |
You could download your engine data from your EFIS, and look at both
fuel pressure and fuel flow simultaneously. I don't think there is an
issue with your fuel pressure sensor, but it would be good to see what
was happening on fuel flow at the same time pressure was dropping. The
mechanical pump is supposed to be able to handle up to -2 psi input, i.e
overcoming an uphill flow on the input side.
There is one other possibility. You could have a leak between the
electric pump and the mechanical pump. If that is the case, the
mechanical pump sucks air through the leak, which reduces the pressure
to the engine, while the electric pump will over come this.
Rule out the chance of an air leak between boost pump and mechanical
before assuming that mechanical pump is bad.
On 10/20/2013 2:46 PM, Linn Walters wrote:
> With the info presented I think you're spot on. I agree with the call
> to Lycoming .... they should ship you a new pump. Up to you to do the
> R&R which has always been a PITA for me. My best guess is that there
> is some small piece of trash (don't know what else to call it) hung up
> in one of the valves.
> Linn
> On 10/20/2013 4:47 PM, Bob Leffler wrote:
>>
>> As several already are aware, I had some fuel flow issues on my first
>> flight. At the time, in the air, I wasnt quite sure what the issue
>> may have been. It was initially looking like a blocked fuel line. The
>> symptom was that the fuel pressure dropped significantly, but came
>> back up with the electric fuel pump turned on and switching the
>> tanks. I promptly landed and started looking for the root cause.
>>
>> 1.The left and right tank fuel flow (measured at the firewall,
>> forward of the filter and pump) was 58 gallons/hour. Rules out a
>> blockage aft of the firewall.
>>
>> 2.The fuel vents are not obstructed
>>
>> I ran the engine in a static test. Was getting about 20psi on the
>> engine fuel pump and about 26psi with the electric fuel pump enabled.
>> Since this is all within specifications, this is the worst of all the
>> scenarios. No root cause and everything seems to be working as designed.
>>
>> This morning I flew for about an hour on flight #2.
>>
>> When I turned off the electric fuel pump, fuel pressure started to
>> immediately drop. I let it drop to about 10psi before I re-engaged
>> the electric fuel pump. With the electric fuel pump running, I was
>> getting 26psi. I repeated this scenario multiple times on both fuel
>> tanks during the flight. Results were pretty consistent.
>>
>> Its looking like I may have a bad fuel pump on this 1 SNEW
>> YIO-540-D4A5. I plan on giving Lycoming a call in the morning.
>>
>> My questions is there any other scenarios that Im overlooking that
>> may yield similar symptoms?
>>
>> Thanks,
>>
>> bob
>>
>> *
>>
>>
>> *
>>
>> No virus found in this message.
>> Checked by AVG - www.avg.com <http://www.avg.com>
>> 10/20/13
>>
>
> *
>
>
> *
Message 6
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Here's the Fuel Flow and Fuel Pressure overlaid. The dips are consistent
when I turned off the electric fuel pump. An interesting anomaly is that
the fuel pressure is higher during taxi with the boost pump off.
Finding a fuel leak is pretty straight forward, especially with the aid of
the blue dye. How do you find a connection that doesn't leak fuel, but does
allow air?
bob
-----Original Message-----
From: owner-rv10-list-server@matronics.com
[mailto:owner-rv10-list-server@matronics.com] On Behalf Of Kelly McMullen
Sent: Sunday, October 20, 2013 6:37 PM
Subject: Re: RV10-List: Fuel Pump Issue
<mailto:kellym@aviating.com> kellym@aviating.com>
You could download your engine data from your EFIS, and look at both fuel
pressure and fuel flow simultaneously. I don't think there is an issue with
your fuel pressure sensor, but it would be good to see what was happening on
fuel flow at the same time pressure was dropping. The mechanical pump is
supposed to be able to handle up to -2 psi input, i.e overcoming an uphill
flow on the input side.
There is one other possibility. You could have a leak between the electric
pump and the mechanical pump. If that is the case, the mechanical pump sucks
air through the leak, which reduces the pressure to the engine, while the
electric pump will over come this.
Rule out the chance of an air leak between boost pump and mechanical before
assuming that mechanical pump is bad.
On 10/20/2013 2:46 PM, Linn Walters wrote:
> With the info presented I think you're spot on. I agree with the call
> to Lycoming .... they should ship you a new pump. Up to you to do the
> R&R which has always been a PITA for me. My best guess is that there
> is some small piece of trash (don't know what else to call it) hung up
> in one of the valves.
> Linn
> On 10/20/2013 4:47 PM, Bob Leffler wrote:
>>
>> As several already are aware, I had some fuel flow issues on my first
>> flight. At the time, in the air, I wasn't quite sure what the issue
>> may have been. It was initially looking like a blocked fuel line. The
>> symptom was that the fuel pressure dropped significantly, but came
>> back up with the electric fuel pump turned on and switching the
>> tanks. I promptly landed and started looking for the root cause.
>>
>> 1.The left and right tank fuel flow (measured at the firewall,
>> forward of the filter and pump) was 58 gallons/hour. Rules out a
>> blockage aft of the firewall.
>>
>> 2.The fuel vents are not obstructed
>>
>> I ran the engine in a static test. Was getting about 20psi on the
>> engine fuel pump and about 26psi with the electric fuel pump enabled.
>> Since this is all within specifications, this is the worst of all the
>> scenarios. No root cause and everything seems to be working as designed.
>>
>> This morning I flew for about an hour on flight #2.
>>
>> When I turned off the electric fuel pump, fuel pressure started to
>> immediately drop. I let it drop to about 10psi before I re-engaged
>> the electric fuel pump. With the electric fuel pump running, I was
>> getting 26psi. I repeated this scenario multiple times on both fuel
>> tanks during the flight. Results were pretty consistent.
>>
>> It's looking like I may have a bad fuel pump on this 1 SNEW
>> YIO-540-D4A5. I plan on giving Lycoming a call in the morning.
>>
>> My questions is there any other scenarios that I'm overlooking that
>> may yield similar symptoms?
>>
>> Thanks,
>>
>> bob
>>
>> *
>>
>>
>> *
>>
>> No virus found in this message.
>> Checked by AVG - <http://www.avg.com> www.avg.com < <http://www.avg.com>
http://www.avg.com>
>> 10/20/13
>>
>
> *
>
>
> *
http://www.matronics.com/Navigator?RV10-List
http://www.matronics.com/contribution
Message 7
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| Subject: | Re: Fuel Pump Issue |
Good point Kelly. I had an air leak in the fuel line between the tank
and wobble pump on my Pitts. It almost drove me nuts .... well, more
nuts! I couldn't see that the rudder pedal had worn a hole in the hard
line. My fault .... the result of poor repairs .... but it was really
difficult to find since the problem .... engine surged like an old
Sopwith .... because the rudder pedal would cover the hole and 'fix' the
problem!!! The leaking fuel was so slight that it evaporated and left
no smell. Good call!
Linn
On 10/20/2013 6:37 PM, Kelly McMullen wrote:
>
> You could download your engine data from your EFIS, and look at both
> fuel pressure and fuel flow simultaneously. I don't think there is an
> issue with your fuel pressure sensor, but it would be good to see what
> was happening on fuel flow at the same time pressure was dropping. The
> mechanical pump is supposed to be able to handle up to -2 psi input,
> i.e overcoming an uphill flow on the input side.
> There is one other possibility. You could have a leak between the
> electric pump and the mechanical pump. If that is the case, the
> mechanical pump sucks air through the leak, which reduces the pressure
> to the engine, while the electric pump will over come this.
> Rule out the chance of an air leak between boost pump and mechanical
> before assuming that mechanical pump is bad.
>
> On 10/20/2013 2:46 PM, Linn Walters wrote:
>> With the info presented I think you're spot on. I agree with the call
>> to Lycoming .... they should ship you a new pump. Up to you to do the
>> R&R which has always been a PITA for me. My best guess is that there
>> is some small piece of trash (don't know what else to call it) hung
>> up in one of the valves.
>> Linn
>> On 10/20/2013 4:47 PM, Bob Leffler wrote:
>>>
>>> As several already are aware, I had some fuel flow issues on my
>>> first flight. At the time, in the air, I wasnt quite sure what the
>>> issue may have been. It was initially looking like a blocked fuel
>>> line. The symptom was that the fuel pressure dropped significantly,
>>> but came back up with the electric fuel pump turned on and switching
>>> the tanks. I promptly landed and started looking for the root cause.
>>>
>>> 1.The left and right tank fuel flow (measured at the firewall,
>>> forward of the filter and pump) was 58 gallons/hour. Rules out a
>>> blockage aft of the firewall.
>>>
>>> 2.The fuel vents are not obstructed
>>>
>>> I ran the engine in a static test. Was getting about 20psi on the
>>> engine fuel pump and about 26psi with the electric fuel pump
>>> enabled. Since this is all within specifications, this is the worst
>>> of all the scenarios. No root cause and everything seems to be
>>> working as designed.
>>>
>>> This morning I flew for about an hour on flight #2.
>>>
>>> When I turned off the electric fuel pump, fuel pressure started to
>>> immediately drop. I let it drop to about 10psi before I re-engaged
>>> the electric fuel pump. With the electric fuel pump running, I was
>>> getting 26psi. I repeated this scenario multiple times on both fuel
>>> tanks during the flight. Results were pretty consistent.
>>>
>>> Its looking like I may have a bad fuel pump on this 1 SNEW
>>> YIO-540-D4A5. I plan on giving Lycoming a call in the morning.
>>>
>>> My questions is there any other scenarios that Im overlooking that
>>> may yield similar symptoms?
>>>
>>> Thanks,
>>>
>>> bob
>>>
>>> *
>>>
>>>
>>> *
>>>
>>> No virus found in this message.
>>> Checked by AVG - www.avg.com <http://www.avg.com>
>>> 10/20/13
>>>
>>
>> *
>>
>>
>> *
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
>
>
Message 8
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| Subject: | Re: Fuel Pump Issue |
Si nce you can't reproduce this on the ground I am wondering if you have an
airflow created vacuum on the tank vents.=C2- I may be all wet, but if t
here is a difference between flight and ground, it shouldn't be a mechanica
l problem.
Gary Specketer
----- Original Message -----
From: "Bob Leffler" <rv@thelefflers.com>n't
Sent: Sunday, October 20, 2013 4:47:25 PM
Subject: RV10-List: Fuel Pump Issue
As several already are aware, I had some fuel flow issues on my first fligh
t.=C2- At the time, in the air, I wasn=99t quite sure what the issu
e may have been.=C2- It was initially looking like a blocked fuel line.
=C2- The symptom was that the fuel pressure dropped significantly, but ca
me back up with the electric fuel pump turned on and switching the tanks.
=C2- I promptly landed and started looking for the root cause.
=C2-
1. =C2-=C2-=C2-=C2-=C2-=C2- The left and right tank fuel flow (
measured at the firewall, forward of the filter and pump) was 58 gallons/ho
ur.=C2- Rules out a blockage aft of the firewall.
2. =C2-=C2-=C2-=C2-=C2-=C2- The fuel vents are not obstructed
=C2-
I ran the engine in a static test.=C2-=C2- Was getting about 20psi on t
he engine fuel pump and about 26psi with the electric fuel pump enabled.=C2
- Since this is all within specifications, this is the worst of all the s
cenarios.=C2- No root cause and everything seems to be working as designe
d.
=C2-
This morning I flew for about an hour on flight #2.
=C2-
When I turned off the electric fuel pump, fuel pressure started to immediat
ely drop.=C2- I let it drop to about 10psi before I re-engaged the electr
ic fuel pump.=C2- With the electric fuel pump running, I was getting 26ps
i.=C2- I repeated this scenario multiple times on both fuel tanks during
the flight.=C2- Results were pretty consistent.
=C2-
It=99s looking like I may=C2- have a bad fuel pump on this 1 SNEW Y
IO-540-D4A5.=C2- I plan on giving Lycoming a call in the morning.
=C2-
My questions is there any other scenarios that I=99m overlooking that
may yield similar symptoms?
=C2-
Thanks,
=C2-
bob
=C2-
============
==
Message 9
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So in summary you get good fuel pressure from the mechanical pump on the
ground in a static run up, and low fuel pressure flying. The main
difference between these too conditions is the actual fuel flow (low for the
static test, high for flying). Additionally your testing ruled out typical
fuel line issues.
I agree the most obvious suspect is the mechanical fuel pump. I'd guess
leaking around the pump diaphragm that at low fuel flow is not enough to
drop pressure, but at high flow the leak around the diaphragm increases
equivalent total fuel flow so pressure drops..
Just my guess - but I agree with you calling Lycoming for a new mechanical
pump.
Carl
From: owner-rv10-list-server@matronics.com
[mailto:owner-rv10-list-server@matronics.com] On Behalf Of Bob Leffler
Sent: Sunday, October 20, 2013 6:46 PM
Subject: RE: RV10-List: Fuel Pump Issue
Here's the Fuel Flow and Fuel Pressure overlaid. The dips are consistent
when I turned off the electric fuel pump. An interesting anomaly is that
the fuel pressure is higher during taxi with the boost pump off.
Finding a fuel leak is pretty straight forward, especially with the aid of
the blue dye. How do you find a connection that doesn't leak fuel, but does
allow air?
bob
-----Original Message-----
From: owner-rv10-list-server@matronics.com
[mailto:owner-rv10-list-server@matronics.com] On Behalf Of Kelly McMullen
Sent: Sunday, October 20, 2013 6:37 PM
Subject: Re: RV10-List: Fuel Pump Issue
<mailto:kellym@aviating.com> kellym@aviating.com>
You could download your engine data from your EFIS, and look at both fuel
pressure and fuel flow simultaneously. I don't think there is an issue with
your fuel pressure sensor, but it would be good to see what was happening on
fuel flow at the same time pressure was dropping. The mechanical pump is
supposed to be able to handle up to -2 psi input, i.e overcoming an uphill
flow on the input side.
There is one other possibility. You could have a leak between the electric
pump and the mechanical pump. If that is the case, the mechanical pump sucks
air through the leak, which reduces the pressure to the engine, while the
electric pump will over come this.
Rule out the chance of an air leak between boost pump and mechanical before
assuming that mechanical pump is bad.
On 10/20/2013 2:46 PM, Linn Walters wrote:
> With the info presented I think you're spot on. I agree with the call
> to Lycoming .... they should ship you a new pump. Up to you to do the
> R&R which has always been a PITA for me. My best guess is that there
> is some small piece of trash (don't know what else to call it) hung up
> in one of the valves.
> Linn
> On 10/20/2013 4:47 PM, Bob Leffler wrote:
>>
>> As several already are aware, I had some fuel flow issues on my first
>> flight. At the time, in the air, I wasn't quite sure what the issue
>> may have been. It was initially looking like a blocked fuel line. The
>> symptom was that the fuel pressure dropped significantly, but came
>> back up with the electric fuel pump turned on and switching the
>> tanks. I promptly landed and started looking for the root cause.
>>
>> 1.The left and right tank fuel flow (measured at the firewall,
>> forward of the filter and pump) was 58 gallons/hour. Rules out a
>> blockage aft of the firewall.
>>
>> 2.The fuel vents are not obstructed
>>
>> I ran the engine in a static test. Was getting about 20psi on the
>> engine fuel pump and about 26psi with the electric fuel pump enabled.
>> Since this is all within specifications, this is the worst of all the
>> scenarios. No root cause and everything seems to be working as designed.
>>
>> This morning I flew for about an hour on flight #2.
>>
>> When I turned off the electric fuel pump, fuel pressure started to
>> immediately drop. I let it drop to about 10psi before I re-engaged
>> the electric fuel pump. With the electric fuel pump running, I was
>> getting 26psi. I repeated this scenario multiple times on both fuel
>> tanks during the flight. Results were pretty consistent.
>>
>> It's looking like I may have a bad fuel pump on this 1 SNEW
>> YIO-540-D4A5. I plan on giving Lycoming a call in the morning.
>>
>> My questions is there any other scenarios that I'm overlooking that
>> may yield similar symptoms?
>>
>> Thanks,
>>
>> bob
>>
>> *
>>
>>
>> *
>>
>> No virus found in this message.
>> Checked by AVG - <http://www.avg.com> www.avg.com < <http://www.avg.com>
http://www.avg.com>
>> 10/20/13
>>
>
> *
>
>
> *
http://www.matronics.com/Navigator?RV10-List
http://forums.matronics.com
<http://www.matronics.com/contribution>
http://www.matronics.com/contribution
Message 10
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| Subject: | Re: Fuel Pump Issue |
On the ground, throttle and mixture full aft, idle cutoff; turn on
electric pump with tunnel open and cowling off. After pressure comes up,
look for leaks. Anything that lets in air under suction will leak under
pressure. Ideally a couple observers, one in reach of the switch to kill
pressure as soon as leak is spotted.
On 10/20/2013 3:45 PM, Bob Leffler wrote:
>
> Heres the Fuel Flow and Fuel Pressure overlaid. The dips are
> consistent when I turned off the electric fuel pump. An interesting
> anomaly is that the fuel pressure is higher during taxi with the boost
> pump off.
>
> Finding a fuel leak is pretty straight forward, especially with the
> aid of the blue dye. How do you find a connection that doesnt leak
> fuel, but does allow air?
>
> bob
>
> -----Original Message-----
> From: owner-rv10-list-server@matronics.com
> [mailto:owner-rv10-list-server@matronics.com] On Behalf Of Kelly McMullen
> Sent: Sunday, October 20, 2013 6:37 PM
> To: rv10-list@matronics.com
> Subject: Re: RV10-List: Fuel Pump Issue
>
> <mailto:kellym@aviating.com>>
>
> You could download your engine data from your EFIS, and look at both
> fuel pressure and fuel flow simultaneously. I don't think there is an
> issue with your fuel pressure sensor, but it would be good to see what
> was happening on fuel flow at the same time pressure was dropping. The
> mechanical pump is supposed to be able to handle up to -2 psi input,
> i.e overcoming an uphill flow on the input side.
>
> There is one other possibility. You could have a leak between the
> electric pump and the mechanical pump. If that is the case, the
> mechanical pump sucks air through the leak, which reduces the pressure
> to the engine, while the electric pump will over come this.
>
> Rule out the chance of an air leak between boost pump and mechanical
> before assuming that mechanical pump is bad.
>
> On 10/20/2013 2:46 PM, Linn Walters wrote:
>
> > With the info presented I think you're spot on. I agree with the call
>
> > to Lycoming .... they should ship you a new pump. Up to you to do the
>
> > R&R which has always been a PITA for me. My best guess is that there
>
> > is some small piece of trash (don't know what else to call it) hung up
>
> > in one of the valves.
>
> > Linn
>
> > On 10/20/2013 4:47 PM, Bob Leffler wrote:
>
> >>
>
> >> As several already are aware, I had some fuel flow issues on my first
>
> >> flight. At the time, in the air, I wasnt quite sure what the issue
>
> >> may have been. It was initially looking like a blocked fuel line. The
>
> >> symptom was that the fuel pressure dropped significantly, but came
>
> >> back up with the electric fuel pump turned on and switching the
>
> >> tanks. I promptly landed and started looking for the root cause.
>
> >>
>
> >> 1.The left and right tank fuel flow (measured at the firewall,
>
> >> forward of the filter and pump) was 58 gallons/hour. Rules out a
>
> >> blockage aft of the firewall.
>
> >>
>
> >> 2.The fuel vents are not obstructed
>
> >>
>
> >> I ran the engine in a static test. Was getting about 20psi on the
>
> >> engine fuel pump and about 26psi with the electric fuel pump enabled.
>
> >> Since this is all within specifications, this is the worst of all the
>
> >> scenarios. No root cause and everything seems to be working as
> designed.
>
> >>
>
> >> This morning I flew for about an hour on flight #2.
>
> >>
>
> >> When I turned off the electric fuel pump, fuel pressure started to
>
> >> immediately drop. I let it drop to about 10psi before I re-engaged
>
> >> the electric fuel pump. With the electric fuel pump running, I was
>
> >> getting 26psi. I repeated this scenario multiple times on both fuel
>
> >> tanks during the flight. Results were pretty consistent.
>
> >>
>
> >> Its looking like I may have a bad fuel pump on this 1 SNEW
>
> >> YIO-540-D4A5. I plan on giving Lycoming a call in the morning.
>
> >>
>
> >> My questions is there any other scenarios that Im overlooking that
>
> >> may yield similar symptoms?
>
> >>
>
> >> Thanks,
>
> >>
>
> >> bob
>
> >>
>
> >> *
>
> >>
>
> >>
>
> >> *
>
> >>
>
> >> No virus found in this message.
>
> >> Checked by AVG - www.avg.com <http://www.avg.com> <http://www.avg.com>
>
> >> 10/20/13
>
> >>
>
> >
>
> > *
>
> >
>
> >
>
> > *
>
> http://www.matronics.com/Navigator?RV10-List
>
> http://forums.matronics.com
>
> http://www.matronics.com/contribution
>
Message 11
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| Subject: | Re: Fuel Pump Issue |
The likely culprit does sound like the fuel pump, although the fact that
all is well on the ground is interesting. My first project was a Q-2
and when I upgraded from the VW engine to an O-200 I had lots of fuel
starvation issues. After an eternity I chased it down to the fact that
when I had to modify the shape of the cowl it created an area of
negative pressure at the fuel vent. While not too likely your issue,
I'd make sure you have your vents as directed in the plans. Even
something as simple as having the angled cutoff facing the wrong way
could make for interesting problems.
Good luck,
Marcus
On Oct 20, 2013, at 7:11 PM, speckter@comcast.net wrote:
Since you can't reproduce this on the ground I am wondering if you have
an airflow created vacuum on the tank vents. I may be all wet, but if
there is a difference between flight and ground, it shouldn't be a
mechanical problem.
Gary Specketer
From: "Bob Leffler" <rv@thelefflers.com>n't
Sent: Sunday, October 20, 2013 4:47:25 PM
Subject: RV10-List: Fuel Pump Issue
As several already are aware, I had some fuel flow issues on my first
flight. At the time, in the air, I wasn=92t quite sure what the issue
may have been. It was initially looking like a blocked fuel line. The
symptom was that the fuel pressure dropped significantly, but came back
up with the electric fuel pump turned on and switching the tanks. I
promptly landed and started looking for the root cause.
1. The left and right tank fuel flow (measured at the firewall,
forward of the filter and pump) was 58 gallons/hour. Rules out a
blockage aft of the firewall.
2. The fuel vents are not obstructed
I ran the engine in a static test. Was getting about 20psi on the
engine fuel pump and about 26psi with the electric fuel pump enabled.
Since this is all within specifications, this is the worst of all the
scenarios. No root cause and everything seems to be working as
designed.
This morning I flew for about an hour on flight #2.
When I turned off the electric fuel pump, fuel pressure started to
immediately drop. I let it drop to about 10psi before I re-engaged the
electric fuel pump. With the electric fuel pump running, I was getting
26psi. I repeated this scenario multiple times on both fuel tanks
during the flight. Results were pretty consistent.
It=92s looking like I may have a bad fuel pump on this 1 SNEW
YIO-540-D4A5. I plan on giving Lycoming a call in the morning.
My questions is there any other scenarios that I=92m overlooking that
may yield similar symptoms?
Thanks,
bob
get=_blank>http://www.matronics.com/Navigator?RV10-List
p://forums.matronics.com
blank>http://www.matronics.com/contribution
Message 12
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| Subject: | Prop spinner cutouts |
The attached was floating around the archives at some point. I cannot attest
to how well it would work. Also I would advise just waiting until all is on
the plane and an actual sweep of the blades can be down.
-Chris
N919AR
From: owner-rv10-list-server@matronics.com
[mailto:owner-rv10-list-server@matronics.com] On Behalf Of Chris Hukill
Sent: Sunday, October 20, 2013 6:03 PM
Subject: RV10-List: Prop spinner cutouts
I'm trying to determine the optimum cutout dimensions for the blades on the
2 bladed Hartzell blended airfoil prop as Vans sells, using the standard
spinner kit. The instructions tell you to rotate the blades thru full travel
to check for clearance, however I don't have an engine to mount the prop to
yet, and it's not possible to move the blades without one. I am trying to
get as tight of fit as is possible. I have looked at production airplane's
installations, and they have a much larger clearance than I would consider
aesthetic. Has anyone made a template or drawings that would provide the
dimensions that I need?
Chris Hukill
Message 13
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| Subject: | Re: Prop spinner cutouts |
Chris, I made a plate that allowed me to use compressed air via a
regulator to move the blades on the prop. then used cardboard to make
the template. See the following web album for the details.
I=99d be willing to share the plate I made that=99s shown in
the album.
https://plus.google.com/photos/102955683430141812381/albums/5303216259724
767969
Bob Newman
N541RV
From: Chris Hukill
Sent: Sunday, October 20, 2013 6:03 PM
Subject: RV10-List: Prop spinner cutouts
I'm trying to determine the optimum cutout dimensions for the blades on
the 2 bladed Hartzell blended airfoil prop as Vans sells, using the
standard spinner kit. The instructions tell you to rotate the blades
thru full travel to check for clearance, however I don't have an engine
to mount the prop to yet, and it's not possible to move the blades
without one. I am trying to get as tight of fit as is possible. I have
looked at production airplane's installations, and they have a much
larger clearance than I would consider aesthetic. Has anyone made a
template or drawings that would provide the dimensions that I need?
Chris Hukill
Message 14
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| Subject: | Re: Fuel Pump Issue |
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