Matronics Email Lists Forum Index Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
 
 Get Email Distribution Too!Get Email Distribution Too!    FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Lycoming O-360 Fuel Flow Rate
Goto page 1, 2  Next
 
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> RV-List
View previous topic :: View next topic  
Author Message
Matt Dralle
Site Admin


Joined: 08 Nov 2005
Posts: 25204
Location: Livermore CA USA

PostPosted: Fri Dec 18, 2015 2:40 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?

I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?

Thanks for the feedback,

Matt

-
Matt Dralle

RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 210+ Hours TTSN - Version 2.0 Now Flying!

RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 300+ Hours - Full Flyer Mode!

Matt's Livermore Airport Live ATC Stream!
Check out the live ATC stream directly from my hangar at the Livermore
Airport. Includes both Tower and Ground transmissions. Archives too!
For entertainment purposes only. http://klvk.matronics.com


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Matt Dralle
Matronics Email List Administrator
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Matt Dralle
Site Admin


Joined: 08 Nov 2005
Posts: 25204
Location: Livermore CA USA

PostPosted: Fri Dec 18, 2015 2:40 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?

I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?

Thanks for the feedback,

Matt

-
Matt Dralle

RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 210+ Hours TTSN - Version 2.0 Now Flying!

RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 300+ Hours - Full Flyer Mode!

Matt's Livermore Airport Live ATC Stream!
Check out the live ATC stream directly from my hangar at the Livermore
Airport. Includes both Tower and Ground transmissions. Archives too!
For entertainment purposes only. http://klvk.matronics.com


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Matt Dralle
Matronics Email List Administrator
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Matt Dralle
Site Admin


Joined: 08 Nov 2005
Posts: 25204
Location: Livermore CA USA

PostPosted: Fri Dec 18, 2015 2:40 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?

I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?

Thanks for the feedback,

Matt

-
Matt Dralle

RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 210+ Hours TTSN - Version 2.0 Now Flying!

RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 300+ Hours - Full Flyer Mode!

Matt's Livermore Airport Live ATC Stream!
Check out the live ATC stream directly from my hangar at the Livermore
Airport. Includes both Tower and Ground transmissions. Archives too!
For entertainment purposes only. http://klvk.matronics.com


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Matt Dralle
Matronics Email List Administrator
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Matt Dralle
Site Admin


Joined: 08 Nov 2005
Posts: 25204
Location: Livermore CA USA

PostPosted: Fri Dec 18, 2015 2:43 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?

I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?

Thanks for the feedback,

Matt

-
Matt Dralle

RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 210+ Hours TTSN - Version 2.0 Now Flying!

RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 300+ Hours - Full Flyer Mode!

Matt's Livermore Airport Live ATC Stream!
Check out the live ATC stream directly from my hangar at the Livermore
Airport. Includes both Tower and Ground transmissions. Archives too!
For entertainment purposes only. http://klvk.matronics.com


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Matt Dralle
Matronics Email List Administrator
Back to top
View user's profile Send private message Send e-mail Visit poster's website
ceengland7(at)gmail.com
Guest





PostPosted: Fri Dec 18, 2015 3:26 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

On 12/18/2015 4:38 PM, Matt Dralle wrote:
Quote:

I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?

I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?

Thanks for the feedback,

Matt

-
Matt Dralle
Never paid much attention to my flow when doing a static runup, but that

doesn't sound too unreasonable. If CS & flat pitch, it won't take much
power to get to 2400rpm. What's the MAP? You should be able to use Lyc's
power charts to see MAP/rpm/power. 75% on a 180 is around 10 GPH, if
leaned. Obviously lower fuel flow if you're under 24".

I think that the FAA recommends 125% of max power flow if running a pump
(150% for gravity feed). Max power flow would be (180 * .6)/6=18GPH.
That would assume a very rich mixture of .6 lbs per HP per hour. So your
electric pump flow sounds more than adequate.

It's really odd that you didn't see any degraded performance when your
flow went from 17 down to 9 gph in climbout, unless it's some sort of
instrumentation issue giving false readings. Hard to explain two
different flow monitors making the same error, but hard to explain the
performance, too. Smile

Having said that, if you were seeing 9gph in a full power (2700rpm, full
rich, 29"MAP) before, and you're now seeing the same flow on the ground,
with less than full throttle, flat pitch & 2400 rpm, then *something*
must be better now.


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List
Back to top
Kellym



Joined: 10 Jan 2006
Posts: 1700
Location: Sun Lakes AZ

PostPosted: Fri Dec 18, 2015 4:30 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

While fuel flow numbers are good general indicators, EGT will tell you
more. On takeoff at sea level you should see 1200-1300 EGT with 1250
optimal. If your fuel flow is too low EGT will go well above 1300.
Assuming 180 hp version, Fuel flow for takeoff should be around 16-18
gph. Cruise at 75% should be 9-9.5 gph.

On 12/18/2015 4:25 PM, Charlie England wrote:
Quote:


On 12/18/2015 4:38 PM, Matt Dralle wrote:
>
> I'm still chasing down this weird problem with low fuel flow rates on
> the RV-6. I've replaced the mechanical fuel pump and got a rebuilt
> 4-5 carburetor, both of which were well over do for
> replacement/overhaul anyway. I haven't put the cowling back on yet,
> but I did a static run up to about 2350-2400 and am seeing about
> 9gph, which seems low to me?
>
> I pulled the fuel line off the carburetor and turned the electric
> fuel pump on and saw about 21 GPH flow. Is that considered "normal"
> or too low?
>
> Thanks for the feedback,
>
> Matt
>
> -
> Matt Dralle
Never paid much attention to my flow when doing a static runup, but
that doesn't sound too unreasonable. If CS & flat pitch, it won't take
much power to get to 2400rpm. What's the MAP? You should be able to
use Lyc's power charts to see MAP/rpm/power. 75% on a 180 is around 10
GPH, if leaned. Obviously lower fuel flow if you're under 24".

I think that the FAA recommends 125% of max power flow if running a
pump (150% for gravity feed). Max power flow would be (180 *
.6)/6=18GPH. That would assume a very rich mixture of .6 lbs per HP
per hour. So your electric pump flow sounds more than adequate.

It's really odd that you didn't see any degraded performance when your
flow went from 17 down to 9 gph in climbout, unless it's some sort of
instrumentation issue giving false readings. Hard to explain two
different flow monitors making the same error, but hard to explain the
performance, too. Smile

Having said that, if you were seeing 9gph in a full power (2700rpm,
full rich, 29"MAP) before, and you're now seeing the same flow on the
ground, with less than full throttle, flat pitch & 2400 rpm, then
*something* must be better now.




- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD
Back to top
View user's profile Send private message
ceengland7(at)gmail.com
Guest





PostPosted: Fri Dec 18, 2015 5:00 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

135 hp & 9 gph would be .4 lbs per hp per hour. That's pretty
impressive, for an air cooled gasoline engine with 8.5-1 compression.
What do the Lyc charts say?

On 12/18/2015 6:28 PM, Kelly McMullen wrote:
Quote:


While fuel flow numbers are good general indicators, EGT will tell you
more. On takeoff at sea level you should see 1200-1300 EGT with 1250
optimal. If your fuel flow is too low EGT will go well above 1300.
Assuming 180 hp version, Fuel flow for takeoff should be around 16-18
gph. Cruise at 75% should be 9-9.5 gph.

On 12/18/2015 4:25 PM, Charlie England wrote:
>
>
> On 12/18/2015 4:38 PM, Matt Dralle wrote:
>>
>>
>>
>> I'm still chasing down this weird problem with low fuel flow rates
>> on the RV-6. I've replaced the mechanical fuel pump and got a
>> rebuilt 4-5 carburetor, both of which were well over do for
>> replacement/overhaul anyway. I haven't put the cowling back on yet,
>> but I did a static run up to about 2350-2400 and am seeing about
>> 9gph, which seems low to me?
>>
>> I pulled the fuel line off the carburetor and turned the electric
>> fuel pump on and saw about 21 GPH flow. Is that considered "normal"
>> or too low?
>>
>> Thanks for the feedback,
>>
>> Matt
>>
>> -
>> Matt Dralle
> Never paid much attention to my flow when doing a static runup, but
> that doesn't sound too unreasonable. If CS & flat pitch, it won't
> take much power to get to 2400rpm. What's the MAP? You should be able
> to use Lyc's power charts to see MAP/rpm/power. 75% on a 180 is
> around 10 GPH, if leaned. Obviously lower fuel flow if you're under 24".
>
> I think that the FAA recommends 125% of max power flow if running a
> pump (150% for gravity feed). Max power flow would be (180 *
> .6)/6=18GPH. That would assume a very rich mixture of .6 lbs per HP
> per hour. So your electric pump flow sounds more than adequate.
>
> It's really odd that you didn't see any degraded performance when
> your flow went from 17 down to 9 gph in climbout, unless it's some
> sort of instrumentation issue giving false readings. Hard to explain
> two different flow monitors making the same error, but hard to
> explain the performance, too. Smile
>
> Having said that, if you were seeing 9gph in a full power (2700rpm,
> full rich, 29"MAP) before, and you're now seeing the same flow on the
> ground, with less than full throttle, flat pitch & 2400 rpm, then
> *something* must be better now.


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List
Back to top
flying-nut(at)cfl.rr.com
Guest





PostPosted: Fri Dec 18, 2015 7:02 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

EGT varies significantly depending on where the probes are in relation
to the flange, and also radially. EGT is most valuable as a comparison
to the history ..... significant change in EGT will alert you to a
change in that cylinders operation, but the actual number (historically)
really doesn't tell you much. Properly calibrated FF and a MP gauge
will tell you far more about power.
Linn (IMHO)

On 12/18/2015 7:28 PM, Kelly McMullen wrote:
Quote:


While fuel flow numbers are good general indicators, EGT will tell you
more. On takeoff at sea level you should see 1200-1300 EGT with 1250
optimal. If your fuel flow is too low EGT will go well above 1300.
Assuming 180 hp version, Fuel flow for takeoff should be around 16-18
gph. Cruise at 75% should be 9-9.5 gph.

On 12/18/2015 4:25 PM, Charlie England wrote:
>
>
> On 12/18/2015 4:38 PM, Matt Dralle wrote:
>>
>>
>>
>> I'm still chasing down this weird problem with low fuel flow rates
>> on the RV-6. I've replaced the mechanical fuel pump and got a
>> rebuilt 4-5 carburetor, both of which were well over do for
>> replacement/overhaul anyway. I haven't put the cowling back on yet,
>> but I did a static run up to about 2350-2400 and am seeing about
>> 9gph, which seems low to me?
>>
>> I pulled the fuel line off the carburetor and turned the electric
>> fuel pump on and saw about 21 GPH flow. Is that considered "normal"
>> or too low?
>>
>> Thanks for the feedback,
>>
>> Matt
>>
>> -
>> Matt Dralle
> Never paid much attention to my flow when doing a static runup, but
> that doesn't sound too unreasonable. If CS & flat pitch, it won't
> take much power to get to 2400rpm. What's the MAP? You should be able
> to use Lyc's power charts to see MAP/rpm/power. 75% on a 180 is
> around 10 GPH, if leaned. Obviously lower fuel flow if you're under 24".
>
> I think that the FAA recommends 125% of max power flow if running a
> pump (150% for gravity feed). Max power flow would be (180 *
> .6)/6=18GPH. That would assume a very rich mixture of .6 lbs per HP
> per hour. So your electric pump flow sounds more than adequate.
>
> It's really odd that you didn't see any degraded performance when
> your flow went from 17 down to 9 gph in climbout, unless it's some
> sort of instrumentation issue giving false readings. Hard to explain
> two different flow monitors making the same error, but hard to
> explain the performance, too. Smile
>
> Having said that, if you were seeing 9gph in a full power (2700rpm,
> full rich, 29"MAP) before, and you're now seeing the same flow on the
> ground, with less than full throttle, flat pitch & 2400 rpm, then
> *something* must be better now.
>
>



- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List
Back to top
Kellym



Joined: 10 Jan 2006
Posts: 1700
Location: Sun Lakes AZ

PostPosted: Fri Dec 18, 2015 9:07 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

I don't disagree with your points in general, but they are not
particularly relevant for this situation.
1. His fuel flow has demonstrated to be unreliable, so is not properly
calibrated.
2. At full power installation variations are minimized due to the
velocity and volume of exhaust, compared to cruise settings.
3. 1200-1300 are very reliable numbers. Whether it varies 25 degrees one
way or the other is not important. It is important that it be within
that 100 degree range to indicate combustion approximately 150-200 ROP.
Given he does not know if his fuel flow is working, only the EGT will
confirm fuel flow.
The actual temp will vary from engine to engine and with OAT. That is
why it is a range, not a single number. He wants to know if his fuel
flow is in the ballpark to safely operate the engine, not if it is optimal.

On 12/18/2015 7:55 PM, Linn Walters wrote:
Quote:


EGT varies significantly depending on where the probes are in relation
to the flange, and also radially. EGT is most valuable as a
comparison to the history ..... significant change in EGT will alert
you to a change in that cylinders operation, but the actual number
(historically) really doesn't tell you much. Properly calibrated FF
and a MP gauge will tell you far more about power.
Linn (IMHO)

On 12/18/2015 7:28 PM, Kelly McMullen wrote:
>
>
> While fuel flow numbers are good general indicators, EGT will tell
> you more. On takeoff at sea level you should see 1200-1300 EGT with
> 1250 optimal. If your fuel flow is too low EGT will go well above 1300.
> Assuming 180 hp version, Fuel flow for takeoff should be around 16-18
> gph. Cruise at 75% should be 9-9.5 gph.
>
> On 12/18/2015 4:25 PM, Charlie England wrote:
>>
>>
>> On 12/18/2015 4:38 PM, Matt Dralle wrote:
>>>
>>>
>>>
>>> I'm still chasing down this weird problem with low fuel flow rates
>>> on the RV-6. I've replaced the mechanical fuel pump and got a
>>> rebuilt 4-5 carburetor, both of which were well over do for
>>> replacement/overhaul anyway. I haven't put the cowling back on
>>> yet, but I did a static run up to about 2350-2400 and am seeing
>>> about 9gph, which seems low to me?
>>>
>>> I pulled the fuel line off the carburetor and turned the electric
>>> fuel pump on and saw about 21 GPH flow. Is that considered
>>> "normal" or too low?
>>>
>>> Thanks for the feedback,
>>>
>>> Matt
>>>
>>> -
>>> Matt Dralle
>> Never paid much attention to my flow when doing a static runup, but
>> that doesn't sound too unreasonable. If CS & flat pitch, it won't
>> take much power to get to 2400rpm. What's the MAP? You should be
>> able to use Lyc's power charts to see MAP/rpm/power. 75% on a 180 is
>> around 10 GPH, if leaned. Obviously lower fuel flow if you're under
>> 24".
>>
>> I think that the FAA recommends 125% of max power flow if running a
>> pump (150% for gravity feed). Max power flow would be (180 *
>> .6)/6=18GPH. That would assume a very rich mixture of .6 lbs per HP
>> per hour. So your electric pump flow sounds more than adequate.
>>
>> It's really odd that you didn't see any degraded performance when
>> your flow went from 17 down to 9 gph in climbout, unless it's some
>> sort of instrumentation issue giving false readings. Hard to explain
>> two different flow monitors making the same error, but hard to
>> explain the performance, too. Smile
>>
>> Having said that, if you were seeing 9gph in a full power (2700rpm,
>> full rich, 29"MAP) before, and you're now seeing the same flow on
>> the ground, with less than full throttle, flat pitch & 2400 rpm,
>> then *something* must be better now.
>>
>>
>>
>>
>



- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD
Back to top
View user's profile Send private message
flying-nut(at)cfl.rr.com
Guest





PostPosted: Sat Dec 19, 2015 4:52 am    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

We really do agree ..... for Matt's case. Too many listers (me included
Razz ) read posts and take the content as being applicable in a broad
sense. I didn't want a whole new thread to result because others aren't
getting EGTs in that specific range. I have friends that are completely
anal about their EGT readings ..... especially when they have a new (to
them) engine monitoring system.
Linn

On 12/19/2015 12:05 AM, Kelly McMullen wrote:
Quote:


I don't disagree with your points in general, but they are not
particularly relevant for this situation.
1. His fuel flow has demonstrated to be unreliable, so is not properly
calibrated.
2. At full power installation variations are minimized due to the
velocity and volume of exhaust, compared to cruise settings.
3. 1200-1300 are very reliable numbers. Whether it varies 25 degrees
one way or the other is not important. It is important that it be
within that 100 degree range to indicate combustion approximately
150-200 ROP. Given he does not know if his fuel flow is working, only
the EGT will confirm fuel flow.
The actual temp will vary from engine to engine and with OAT. That is
why it is a range, not a single number. He wants to know if his fuel
flow is in the ballpark to safely operate the engine, not if it is
optimal.

On 12/18/2015 7:55 PM, Linn Walters wrote:
>
>
> EGT varies significantly depending on where the probes are in
> relation to the flange, and also radially. EGT is most valuable as a
> comparison to the history ..... significant change in EGT will alert
> you to a change in that cylinders operation, but the actual number
> (historically) really doesn't tell you much. Properly calibrated FF
> and a MP gauge will tell you far more about power.
> Linn (IMHO)
>
> On 12/18/2015 7:28 PM, Kelly McMullen wrote:
>>
>>
>> While fuel flow numbers are good general indicators, EGT will tell
>> you more. On takeoff at sea level you should see 1200-1300 EGT with
>> 1250 optimal. If your fuel flow is too low EGT will go well above 1300.
>> Assuming 180 hp version, Fuel flow for takeoff should be around
>> 16-18 gph. Cruise at 75% should be 9-9.5 gph.
>>
>> On 12/18/2015 4:25 PM, Charlie England wrote:
>>>
>>>
>>> On 12/18/2015 4:38 PM, Matt Dralle wrote:
>>>>
>>>>
>>>>
>>>> I'm still chasing down this weird problem with low fuel flow rates
>>>> on the RV-6. I've replaced the mechanical fuel pump and got a
>>>> rebuilt 4-5 carburetor, both of which were well over do for
>>>> replacement/overhaul anyway. I haven't put the cowling back on
>>>> yet, but I did a static run up to about 2350-2400 and am seeing
>>>> about 9gph, which seems low to me?
>>>>
>>>> I pulled the fuel line off the carburetor and turned the electric
>>>> fuel pump on and saw about 21 GPH flow. Is that considered
>>>> "normal" or too low?
>>>>
>>>> Thanks for the feedback,
>>>>
>>>> Matt
>>>>
>>>> -
>>>> Matt Dralle
>>> Never paid much attention to my flow when doing a static runup, but
>>> that doesn't sound too unreasonable. If CS & flat pitch, it won't
>>> take much power to get to 2400rpm. What's the MAP? You should be
>>> able to use Lyc's power charts to see MAP/rpm/power. 75% on a 180
>>> is around 10 GPH, if leaned. Obviously lower fuel flow if you're
>>> under 24".
>>>
>>> I think that the FAA recommends 125% of max power flow if running a
>>> pump (150% for gravity feed). Max power flow would be (180 *
>>> .6)/6=18GPH. That would assume a very rich mixture of .6 lbs per HP
>>> per hour. So your electric pump flow sounds more than adequate.
>>>
>>> It's really odd that you didn't see any degraded performance when
>>> your flow went from 17 down to 9 gph in climbout, unless it's some
>>> sort of instrumentation issue giving false readings. Hard to
>>> explain two different flow monitors making the same error, but hard
>>> to explain the performance, too. Smile
>>>
>>> Having said that, if you were seeing 9gph in a full power (2700rpm,
>>> full rich, 29"MAP) before, and you're now seeing the same flow on
>>> the ground, with less than full throttle, flat pitch & 2400 rpm,
>>> then *something* must be better now.
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>





- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List
Back to top
Hopperdhh(at)aol.com
Guest





PostPosted: Sat Dec 19, 2015 10:47 am    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

Hi Matt,

It wouldn't be too hard to check the calibration of your fuel flow gauge including the sensor. Could you make a restricted fitting so that it flows about 10 to 14 GPH using the electric pump? See how long it takes to fill a 1 quart jar while observing the fuel flow meter. Divide 900 by the time in seconds for GPH. 60 seconds would be 15 GPH. Compare the calculated GPH with what your fuel flow gauge read during the test.

Be careful, obviously!

Just a wild idea, so take it for what its worth!


I know someone (can't name the person!) who put the sensor in backwards while being distracted by a visitor. The readings were low!

Dan
RV-7A 766DH -- flying since 2004



In a message dated 12/18/2015 5:42:20 P.M. Eastern Standard Time, dralle(at)matronics.com writes:
Quote:
I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me? 

I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?

Thanks for the feedback,

Matt


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List
Back to top
Matt Dralle
Site Admin


Joined: 08 Nov 2005
Posts: 25204
Location: Livermore CA USA

PostPosted: Sat Dec 19, 2015 12:47 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

Thank you to everyone that responded!! There were some great comments that got me going down the right path.

Last night I got the cowling back on and took the RV-6 out on the runway and ran it up to full power with the intent of carefully watching the flow rate and aborting the take off if the flow wasn't sufficiently high enough. I'm happy to report that the flow rate climbed nicely up though the teens as my takeoff roll progressed. I lifted off around 15-16 gph and decided to take it around the pattern. As I climbed through the crosswind to downwind turn I noted that the flow was in the 18.5gph range, RPM was at 2700, and EGTs were low 1300's. After a few more loops around the pattern everything seemed to be working as expected. I took it out of the pattern and dialed it into my normal cruse configuration which is typically 75% power at 2250 RPM and leaned to about 1425 on the hottest EGT. Everything sounded and felt fine. Flow was right at 9.5 GPH per usual.

The only weird thing I noticed was at about 1700 RPM. When I turn from Downwind to Base and go from idle to about 2000 RPM like I usually do, right about 1700 RPM the engine kind of sags and then picks back up. It is very repeatable. Strangely there is no sag on the ground after a touch and go when I push the throttle in fast going from idle to full power anymore like there was with the old carb.

Does anyone have any idea what that sag at 1700 is? Is there a nurd knob on the carb for this specifically?

Thanks again for the great feedback!

Matt Dralle

At 02:38 PM 12/18/2015 Friday, Matt Dralle wrote:

Quote:
I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?

I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?

Thanks for the feedback,

Matt

-
Matt Dralle

RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 210+ Hours TTSN - Version 2.0 Now Flying!

RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 300+ Hours - Full Flyer Mode!

Matt's Livermore Airport Live ATC Stream!
Check out the live ATC stream directly from my hangar at the Livermore
Airport. Includes both Tower and Ground transmissions. Archives too!
For entertainment purposes only. http://klvk.matronics.com


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Matt Dralle
Matronics Email List Administrator
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Matt Dralle
Site Admin


Joined: 08 Nov 2005
Posts: 25204
Location: Livermore CA USA

PostPosted: Sat Dec 19, 2015 12:47 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

Thank you to everyone that responded!! There were some great comments that got me going down the right path.

Last night I got the cowling back on and took the RV-6 out on the runway and ran it up to full power with the intent of carefully watching the flow rate and aborting the take off if the flow wasn't sufficiently high enough. I'm happy to report that the flow rate climbed nicely up though the teens as my takeoff roll progressed. I lifted off around 15-16 gph and decided to take it around the pattern. As I climbed through the crosswind to downwind turn I noted that the flow was in the 18.5gph range, RPM was at 2700, and EGTs were low 1300's. After a few more loops around the pattern everything seemed to be working as expected. I took it out of the pattern and dialed it into my normal cruse configuration which is typically 75% power at 2250 RPM and leaned to about 1425 on the hottest EGT. Everything sounded and felt fine. Flow was right at 9.5 GPH per usual.

The only weird thing I noticed was at about 1700 RPM. When I turn from Downwind to Base and go from idle to about 2000 RPM like I usually do, right about 1700 RPM the engine kind of sags and then picks back up. It is very repeatable. Strangely there is no sag on the ground after a touch and go when I push the throttle in fast going from idle to full power anymore like there was with the old carb.

Does anyone have any idea what that sag at 1700 is? Is there a nurd knob on the carb for this specifically?

Thanks again for the great feedback!

Matt Dralle

At 02:38 PM 12/18/2015 Friday, Matt Dralle wrote:

Quote:
I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?

I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?

Thanks for the feedback,

Matt

-
Matt Dralle

RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 210+ Hours TTSN - Version 2.0 Now Flying!

RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 300+ Hours - Full Flyer Mode!

Matt's Livermore Airport Live ATC Stream!
Check out the live ATC stream directly from my hangar at the Livermore
Airport. Includes both Tower and Ground transmissions. Archives too!
For entertainment purposes only. http://klvk.matronics.com


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Matt Dralle
Matronics Email List Administrator
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Matt Dralle
Site Admin


Joined: 08 Nov 2005
Posts: 25204
Location: Livermore CA USA

PostPosted: Sat Dec 19, 2015 12:48 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

Thank you to everyone that responded!! There were some great comments that got me going down the right path.

Last night I got the cowling back on and took the RV-6 out on the runway and ran it up to full power with the intent of carefully watching the flow rate and aborting the take off if the flow wasn't sufficiently high enough. I'm happy to report that the flow rate climbed nicely up though the teens as my takeoff roll progressed. I lifted off around 15-16 gph and decided to take it around the pattern. As I climbed through the crosswind to downwind turn I noted that the flow was in the 18.5gph range, RPM was at 2700, and EGTs were low 1300's. After a few more loops around the pattern everything seemed to be working as expected. I took it out of the pattern and dialed it into my normal cruse configuration which is typically 75% power at 2250 RPM and leaned to about 1425 on the hottest EGT. Everything sounded and felt fine. Flow was right at 9.5 GPH per usual.

The only weird thing I noticed was at about 1700 RPM. When I turn from Downwind to Base and go from idle to about 2000 RPM like I usually do, right about 1700 RPM the engine kind of sags and then picks back up. It is very repeatable. Strangely there is no sag on the ground after a touch and go when I push the throttle in fast going from idle to full power anymore like there was with the old carb.

Does anyone have any idea what that sag at 1700 is? Is there a nurd knob on the carb for this specifically?

Thanks again for the great feedback!

Matt Dralle

At 02:38 PM 12/18/2015 Friday, Matt Dralle wrote:

Quote:
I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?

I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?

Thanks for the feedback,

Matt

-
Matt Dralle

RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 210+ Hours TTSN - Version 2.0 Now Flying!

RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 300+ Hours - Full Flyer Mode!

Matt's Livermore Airport Live ATC Stream!
Check out the live ATC stream directly from my hangar at the Livermore
Airport. Includes both Tower and Ground transmissions. Archives too!
For entertainment purposes only. http://klvk.matronics.com


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Matt Dralle
Matronics Email List Administrator
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Matt Dralle
Site Admin


Joined: 08 Nov 2005
Posts: 25204
Location: Livermore CA USA

PostPosted: Sat Dec 19, 2015 12:50 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

Thank you to everyone that responded!! There were some great comments that got me going down the right path.

Last night I got the cowling back on and took the RV-6 out on the runway and ran it up to full power with the intent of carefully watching the flow rate and aborting the take off if the flow wasn't sufficiently high enough. I'm happy to report that the flow rate climbed nicely up though the teens as my takeoff roll progressed. I lifted off around 15-16 gph and decided to take it around the pattern. As I climbed through the crosswind to downwind turn I noted that the flow was in the 18.5gph range, RPM was at 2700, and EGTs were low 1300's. After a few more loops around the pattern everything seemed to be working as expected. I took it out of the pattern and dialed it into my normal cruse configuration which is typically 75% power at 2250 RPM and leaned to about 1425 on the hottest EGT. Everything sounded and felt fine. Flow was right at 9.5 GPH per usual.

The only weird thing I noticed was at about 1700 RPM. When I turn from Downwind to Base and go from idle to about 2000 RPM like I usually do, right about 1700 RPM the engine kind of sags and then picks back up. It is very repeatable. Strangely there is no sag on the ground after a touch and go when I push the throttle in fast going from idle to full power anymore like there was with the old carb.

Does anyone have any idea what that sag at 1700 is? Is there a nurd knob on the carb for this specifically?

Thanks again for the great feedback!

Matt Dralle

At 02:38 PM 12/18/2015 Friday, Matt Dralle wrote:

Quote:
I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?

I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?

Thanks for the feedback,

Matt

-
Matt Dralle

RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 210+ Hours TTSN - Version 2.0 Now Flying!

RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 300+ Hours - Full Flyer Mode!

Matt's Livermore Airport Live ATC Stream!
Check out the live ATC stream directly from my hangar at the Livermore
Airport. Includes both Tower and Ground transmissions. Archives too!
For entertainment purposes only. http://klvk.matronics.com


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Matt Dralle
Matronics Email List Administrator
Back to top
View user's profile Send private message Send e-mail Visit poster's website
kcflyrv(at)comcast.net
Guest





PostPosted: Sat Dec 19, 2015 1:31 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

For me, in the same situation,(in the pattern adding power from idle) this
sag at 1700 has been very common. I have 2100+ hours on my O-360 precision
carburetor RV-6. Always unsettling but never became a more serious issue.

Ken Cantrell

--


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List
Back to top
jhnstniii(at)aol.com
Guest





PostPosted: Sat Dec 19, 2015 8:46 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

Trying leaving the mixture a little lean in the pattern and I think you will find the issue stops happening.
LeRoy Johnston RV-6A Esperanza 1000 hours.

Sent from my iPhone

[quote] On Dec 19, 2015, at 4:30 PM, "Ken Cantrell" <kcflyrv(at)comcast.net> wrote:



For me, in the same situation,(in the pattern adding power from idle) this
sag at 1700 has been very common. I have 2100+ hours on my O-360 precision
carburetor RV-6. Always unsettling but never became a more serious issue.

Ken Cantrell





--


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List
Back to top
ceengland7(at)gmail.com
Guest





PostPosted: Sun Dec 20, 2015 9:17 am    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

I see your problem; you're powering up for landing. Smile

I know that many will disagree with this (having been taught by airline
pilot wannabe's instead of career flight instructors/freight dogs), but
my primary instructor wouldn't let me touch the throttle after going to
idle on downwind. His contention (which I agree with) was that if you
ever have an engine out, how will you land the plane? You'll have no
experience at the task. By staying at idle, it forces you to properly
plan the pattern turns and approach while compensating for wind, etc. It
will also make you adept at staying high (options) & slipping to your
'spot' on the runway. Yes, I know that a c/s prop has higher drag. I
learned to fly in a f/p Luscombe, and used the same technique when I
started flying a f/p T-18, and again in a 200hp, c/s, retract gear Swift
(an elevator on final, compared to an RV). And again when I started
flying RVs.

Just a thought...

Charlie

On 12/19/2015 2:44 PM, Matt Dralle wrote:
Quote:


Thank you to everyone that responded!! There were some great comments that got me going down the right path.

Last night I got the cowling back on and took the RV-6 out on the runway and ran it up to full power with the intent of carefully watching the flow rate and aborting the take off if the flow wasn't sufficiently high enough. I'm happy to report that the flow rate climbed nicely up though the teens as my takeoff roll progressed. I lifted off around 15-16 gph and decided to take it around the pattern. As I climbed through the crosswind to downwind turn I noted that the flow was in the 18.5gph range, RPM was at 2700, and EGTs were low 1300's. After a few more loops around the pattern everything seemed to be working as expected. I took it out of the pattern and dialed it into my normal cruse configuration which is typically 75% power at 2250 RPM and leaned to about 1425 on the hottest EGT. Everything sounded and felt fine. Flow was right at 9.5 GPH per usual.

The only weird thing I noticed was at about 1700 RPM. When I turn from Downwind to Base and go from idle to about 2000 RPM like I usually do, right about 1700 RPM the engine kind of sags and then picks back up. It is very repeatable. Strangely there is no sag on the ground after a touch and go when I push the throttle in fast going from idle to full power anymore like there was with the old carb.

Does anyone have any idea what that sag at 1700 is? Is there a nurd knob on the carb for this specifically?

Thanks again for the great feedback!

Matt Dralle

At 02:38 PM 12/18/2015 Friday, Matt Dralle wrote:

> I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?
>
> I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?
>
> Thanks for the feedback,
>
> Matt
-
Matt Dralle


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List
Back to top
Matt Dralle
Site Admin


Joined: 08 Nov 2005
Posts: 25204
Location: Livermore CA USA

PostPosted: Tue Dec 22, 2015 12:19 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

Well, it was probably the fuel pump. I think my flow rates right after replacing the fuel pump (but before I replaced the carb) were probably alright as they were similar to what I saw after the new carb. But, it was time for a new carb anyway, so I guess it worked out. Btw, as if all of this debacle wasn't frustrating enough, last weekend while trying to test all of this, the battery went dead. Checking the logs it was 36 months ago since I replaced it the last time. Guess that's about right. Sigh. Is it time to fly it yet? I've been working on it enough lately. Wink

Matt Dralle

RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 210+ Hours TTSN - Version 2.0 Now Flying!

RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 300+ Hours - Full Flyer Mode!

Matt's Livermore Airport Live ATC Stream!
Check out the live ATC stream directly from my hangar at the Livermore
Airport. Includes both Tower and Ground transmissions. Archives too!
For entertainment purposes only.

At 10:24 AM 12/21/2015 Monday, you wrote:
Quote:
So what did you do to fix the problem Matt?

Harry Crosby
----------
From: "Matt Dralle" <dralle(at)matronics.com>
To: "RV-List" <rv-list(at)matronics.com>, LycomingEngines-list(at)matronics.com, rv6-list(at)matronics.com, rv10-list(at)matronics.com
Sent: Saturday, December 19, 2015 12:44:41 PM
Subject: RV-List: Re: Lycoming O-360 Fuel Flow Rate



Thank you to everyone that responded!! There were some great comments that got me going down the right path.

Last night I got the cowling back on and took the RV-6 out on the runway and ran it up to full power with the intent of carefully watching the flow rate and aborting the take off if the flow wasn't sufficiently high enough. I'm happy to report that the flow rate climbed nicely up though the teens as my takeoff roll progressed. I lifted off around 15-16 gph and decided to take it around the pattern. As I climbed through the crosswind to downwind turn I noted that the flow was in the 18.5gph range, RPM was at 2700, and EGTs were low 1300's. After a few more loops around the pattern everything seemed to be working as expected. I took it out of the pattern and dialed it into my normal cruse configuration which is typically 75% power at 2250 RPM and leaned to about 1425 on the hottest EGT. Everything sounded and felt fine. Flow was right at 9.5 GPH per usual.

The only weird thing I noticed was at about 1700 RPM. When I turn from Downwind to Base and go from idle to about 2000 RPM like I usually do, right about 1700 RPM the engine kind of sags and then picks back up. It is very repeatable. Strangely there is no sag on the ground after a touch and go when I push the throttle in fast going from idle to full power anymore like there was with the old carb.

Does anyone have any idea what that sag at 1700 is? Is there a nurd knob on the carb for this specifically?

Thanks again for the great feedback!

Matt Dralle

At 02:38 PM 12/18/2015 Friday, Matt Dralle wrote:

>I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?
>
>I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?
>
>Thanks for the feedback,
>
>Matt

-
Matt Dralle


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Matt Dralle
Matronics Email List Administrator
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Matt Dralle
Site Admin


Joined: 08 Nov 2005
Posts: 25204
Location: Livermore CA USA

PostPosted: Tue Dec 22, 2015 12:20 pm    Post subject: Lycoming O-360 Fuel Flow Rate Reply with quote

Well, it was probably the fuel pump. I think my flow rates right after replacing the fuel pump (but before I replaced the carb) were probably alright as they were similar to what I saw after the new carb. But, it was time for a new carb anyway, so I guess it worked out. Btw, as if all of this debacle wasn't frustrating enough, last weekend while trying to test all of this, the battery went dead. Checking the logs it was 36 months ago since I replaced it the last time. Guess that's about right. Sigh. Is it time to fly it yet? I've been working on it enough lately. Wink

Matt Dralle

RV-8 #82880 N998RV "Ruby Vixen"
http://www.mattsrv8.com - Matt's Complete RV-8 Construction Log
http://www.mattsrv8.com/Mishap - Landing Mishap Rebuild Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 210+ Hours TTSN - Version 2.0 Now Flying!

RV-6 #20916 N360EM "The Flyer"
http://www.mattsrv6.com - Matt's RV-6 Revitalization Log
Status: 300+ Hours - Full Flyer Mode!

Matt's Livermore Airport Live ATC Stream!
Check out the live ATC stream directly from my hangar at the Livermore
Airport. Includes both Tower and Ground transmissions. Archives too!
For entertainment purposes only.

At 10:24 AM 12/21/2015 Monday, you wrote:
Quote:
So what did you do to fix the problem Matt?

Harry Crosby
----------
From: "Matt Dralle" <dralle(at)matronics.com>
To: "RV-List" <rv-list(at)matronics.com>, LycomingEngines-list(at)matronics.com, rv6-list(at)matronics.com, rv10-list(at)matronics.com
Sent: Saturday, December 19, 2015 12:44:41 PM
Subject: RV-List: Re: Lycoming O-360 Fuel Flow Rate



Thank you to everyone that responded!! There were some great comments that got me going down the right path.

Last night I got the cowling back on and took the RV-6 out on the runway and ran it up to full power with the intent of carefully watching the flow rate and aborting the take off if the flow wasn't sufficiently high enough. I'm happy to report that the flow rate climbed nicely up though the teens as my takeoff roll progressed. I lifted off around 15-16 gph and decided to take it around the pattern. As I climbed through the crosswind to downwind turn I noted that the flow was in the 18.5gph range, RPM was at 2700, and EGTs were low 1300's. After a few more loops around the pattern everything seemed to be working as expected. I took it out of the pattern and dialed it into my normal cruse configuration which is typically 75% power at 2250 RPM and leaned to about 1425 on the hottest EGT. Everything sounded and felt fine. Flow was right at 9.5 GPH per usual.

The only weird thing I noticed was at about 1700 RPM. When I turn from Downwind to Base and go from idle to about 2000 RPM like I usually do, right about 1700 RPM the engine kind of sags and then picks back up. It is very repeatable. Strangely there is no sag on the ground after a touch and go when I push the throttle in fast going from idle to full power anymore like there was with the old carb.

Does anyone have any idea what that sag at 1700 is? Is there a nurd knob on the carb for this specifically?

Thanks again for the great feedback!

Matt Dralle

At 02:38 PM 12/18/2015 Friday, Matt Dralle wrote:

>I'm still chasing down this weird problem with low fuel flow rates on the RV-6. I've replaced the mechanical fuel pump and got a rebuilt 4-5 carburetor, both of which were well over do for replacement/overhaul anyway. I haven't put the cowling back on yet, but I did a static run up to about 2350-2400 and am seeing about 9gph, which seems low to me?
>
>I pulled the fuel line off the carburetor and turned the electric fuel pump on and saw about 21 GPH flow. Is that considered "normal" or too low?
>
>Thanks for the feedback,
>
>Matt

-
Matt Dralle


- The Matronics RV-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV-List

_________________
Matt Dralle
Matronics Email List Administrator
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> RV-List All times are GMT - 8 Hours
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group