---------------------------------------------------------- RV-List Digest Archive --- Total Messages Posted Sun 12/20/15: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:17 AM - Re: Re: Lycoming O-360 Fuel Flow Rate (Charlie England) 2. 07:45 PM - Re: Re: Lycoming O-360 Fuel Flow Rate (Steve Senegal) ________________________________ Message 1 _____________________________________ Time: 09:17:09 AM PST US Subject: Re: RV-List: Re: Lycoming O-360 Fuel Flow Rate From: Charlie England I see your problem; you're powering up for landing. :-) 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: > > 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 > > ________________________________ Message 2 _____________________________________ Time: 07:45:15 PM PST US From: Steve Senegal Subject: Re: RV-List: Re: Lycoming O-360 Fuel Flow Rate I've been following this issue with interest but maybe I missed something. What fixed the problem? Steve 650.346.6967 Sent from my iPhone between flights. > On Dec 19, 2015, at 12:44, Matt Dralle wrote: > > > 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 > > 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 > > > > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/rv-list Browse Digests http://www.matronics.com/digest/rv-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.