---------------------------------------------------------- RV10-List Digest Archive --- Total Messages Posted Thu 06/14/18: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:06 PM - Spiral Wrap (kearney) 2. 04:47 PM - Ongoing fuel pressure problems (Dan Charrois) 3. 06:08 PM - Re: Ongoing fuel pressure problems (John MacCallum) 4. 07:24 PM - Re: Ongoing fuel pressure problems (Kelly McMullen) 5. 10:33 PM - Re: Ongoing fuel pressure problems (Dan Charrois) 6. 10:44 PM - Re: Ongoing fuel pressure problems (Kelly McMullen) 7. 10:55 PM - Re: Ongoing fuel pressure problems (Bob Turner) ________________________________ Message 1 _____________________________________ Time: 02:06:58 PM PST US Subject: RV10-List: Spiral Wrap From: "kearney" Hi Does anyone have a source / spec for heat resistant spiral wrap. I'd like to use some on the top of my engine so I don't want to use something that would melt. Also, does anyone know how hot it get on top of the engine. I have found some spiral wrap that is good to 160c but am unsure if that will survive -especially after shut down. Cheers Les Read this topic online here: http://forums.matronics.com/viewtopic.php?p=480898#480898 ________________________________ Message 2 _____________________________________ Time: 04:47:46 PM PST US From: Dan Charrois Subject: RV10-List: Ongoing fuel pressure problems Hi everyone. I've had my RV-10 flying for about a year and a half now. Everything's working fine except one issue - I periodically get low fuel pressure warnings when just on the engine pump and haven't been able to isolate the problem. My setup is pretty stock - a factory new Lycoming IO-540 D4A5 through Van's with their pre-installed engine fuel pump, electric fuel pump assembly in the tunnel as per Van's instructions, fuel plumbing as per Van's instructions, etc. The only "deviation" from plans was that I had to install wing root gascolators as per Canada's requirements. My fuel totalizer is in the tunnel also as per instructions, though I realize now that's a bad location in that it tends to over-read by 50% or more when the electric boost pump is on. Not the end of the world since it's only an issue when the electrical boost pump is on (which isn't really that much) and I'd rather it read pessimistically instead of optimistically anyway. Maybe one day I'll relocate it, but I mention it here in case someone thinks it's relevant to my real problem. And the real problem is this - normally in cruise above 10000', I have fuel pressure readings around 19-21 psi. But periodically (and unpredictably) sometimes the fuel pressure will plummet - I've seen it get as low as 10 psi before climbing back up again. Originally, as soon as it would start dropping I'd turn on the electric boost pump but as it's happened more and more often and I've become more brave, I've held off at least a few seconds and so far it's always recovered before the engine started stumbling. I've never seen this happen with the boost pump on - just when the engine pump is working on its own. Though as I said, I don't normally fly with the boost pump on, so I obviously have less data with the boost pump on. What's particularly interesting is that it only seems to happen at higher altitudes. Above 10000' or so, I can count on it happening at least once an hour - at 13000', it sometimes happens every 10 or 15 minutes (though sometimes it doesn't happen at all either for an hour). At 9500', I've seen it happen only rarely, and I don't recall it ever occurring at 8500' or below. When it drops, it tends to fall over the course of about 5-10 seconds and then climb back up over 5-10 seconds. The whole event is over with within 15-20 seconds, and doesn't seem to "linger" at low PSI. I'm not sure if this is "real" or an artifact of sensor filtering of the EFIS. It isn't specific to when the engine is particularly hot - I always climb with the boost pump on, so when the engine is running hotter I never see the issue. This happens after I've been flying around at cruise power settings at altitude, often with a below freezing outside temperature and CHTs in the 310-350 range, and usually lean of peak burning in the neighbourhood of 10 gph. I have a blast tube aimed towards the fuel pump (though not a full shroud). I've even tried removing my gascolator screens in case they were potentially restricting fuel flow. It's been suggested that perhaps my fuel pressure sensor is having issues. I could certainly change it out, but since I haven't seen an issue with the electric boost pump on, and since it only seems to happen at altitude, I would expect if it was a sensor issue neither of these two factors would have an effect. Does anyone have any suggestions on what to try? I have tons of engine sensor data logged from the EFIS that I could send if helpful. I'm a bit apprehensive of changing out the fuel pump (in that I haven't done so before and would want to ensure that a new one is installed correctly so I don't damage anything). Has anyone done that before and could offer any advice? On the other hand, I've lived with this one issue for long enough and as it's the one thing I'm not completely happy with, I would like to try and finally resolve it so I can better trust things. Thanks for any advice! Dan --- Dan Charrois President, Syzygy Research & Technology Phone: 780-961-2213 ________________________________ Message 3 _____________________________________ Time: 06:08:31 PM PST US From: John MacCallum Subject: Re: RV10-List: Ongoing fuel pressure problems Hi Dan, =46rom a Video I watched about Fuel Injected engines as long as there is pos itive pressure above about 5 PSI at high fuel flows to the FI Servo the engi ne will run fine. The Video was from Tempest Aero parts and it talked about E ngine driven Fuel Pumps and Boost Pumps. The Video was Titled, =9CThe Amazing Ubiquitous Diaphragm Fuel Pump.=9D Anyway the Video said nothing to worry about down to about 9 psi. What type o f boost pump do you have? My Andair Electric boost pump is in the tunnel and so is the red cube. I have no issues with inaccurate flow readings but I do occasionally get fuel pressure fluctuations in very hot weather. That is am bient ground temps above 35 C. I solve this by running the boost pump until a t altitude and the OAT has dropped below 30 C. Cheers John MacCallum VH-DUU > On 15 Jun 2018, at 09:45, Dan Charrois wrote: > > > Hi everyone. I've had my RV-10 flying for about a year and a half now. E verything's working fine except one issue - I periodically get low fuel pres sure warnings when just on the engine pump and haven't been able to isolate t he problem. > > My setup is pretty stock - a factory new Lycoming IO-540 D4A5 through Van' s with their pre-installed engine fuel pump, electric fuel pump assembly in t he tunnel as per Van's instructions, fuel plumbing as per Van's instructions , etc. The only "deviation" from plans was that I had to install wing root g ascolators as per Canada's requirements. > > My fuel totalizer is in the tunnel also as per instructions, though I real ize now that's a bad location in that it tends to over-read by 50% or more w hen the electric boost pump is on. Not the end of the world since it's only an issue when the electrical boost pump is on (which isn't really that much ) and I'd rather it read pessimistically instead of optimistically anyway. M aybe one day I'll relocate it, but I mention it here in case someone thinks i t's relevant to my real problem. > > And the real problem is this - normally in cruise above 10000', I have fue l pressure readings around 19-21 psi. But periodically (and unpredictably) s ometimes the fuel pressure will plummet - I've seen it get as low as 10 psi b efore climbing back up again. Originally, as soon as it would start droppin g I'd turn on the electric boost pump but as it's happened more and more oft en and I've become more brave, I've held off at least a few seconds and so f ar it's always recovered before the engine started stumbling. > > I've never seen this happen with the boost pump on - just when the engine p ump is working on its own. Though as I said, I don't normally fly with the b oost pump on, so I obviously have less data with the boost pump on. > > What's particularly interesting is that it only seems to happen at higher a ltitudes. Above 10000' or so, I can count on it happening at least once an h our - at 13000', it sometimes happens every 10 or 15 minutes (though sometim es it doesn't happen at all either for an hour). At 9500', I've seen it hap pen only rarely, and I don't recall it ever occurring at 8500' or below. > > When it drops, it tends to fall over the course of about 5-10 seconds and t hen climb back up over 5-10 seconds. The whole event is over with within 15 -20 seconds, and doesn't seem to "linger" at low PSI. I'm not sure if this i s "real" or an artifact of sensor filtering of the EFIS. > > It isn't specific to when the engine is particularly hot - I always climb w ith the boost pump on, so when the engine is running hotter I never see the i ssue. This happens after I've been flying around at cruise power settings a t altitude, often with a below freezing outside temperature and CHTs in the 3 10-350 range, and usually lean of peak burning in the neighbourhood of 10 gp h. > > I have a blast tube aimed towards the fuel pump (though not a full shroud) . I've even tried removing my gascolator screens in case they were potentia lly restricting fuel flow. > > It's been suggested that perhaps my fuel pressure sensor is having issues. I could certainly change it out, but since I haven't seen an issue with th e electric boost pump on, and since it only seems to happen at altitude, I w ould expect if it was a sensor issue neither of these two factors would have an effect. > > Does anyone have any suggestions on what to try? I have tons of engine se nsor data logged from the EFIS that I could send if helpful. > > I'm a bit apprehensive of changing out the fuel pump (in that I haven't do ne so before and would want to ensure that a new one is installed correctly s o I don't damage anything). Has anyone done that before and could offer any advice? On the other hand, I've lived with this one issue for long enough a nd as it's the one thing I'm not completely happy with, I would like to try a nd finally resolve it so I can better trust things. > > Thanks for any advice! > > Dan > --- > Dan Charrois > President, Syzygy Research & Technology > Phone: 780-961-2213 > > ========================== ========= ========================== ========= ========================== ========= ========================== ========= ========================== ========= > > > ________________________________ Message 4 _____________________________________ Time: 07:24:07 PM PST US From: Kelly McMullen Subject: Re: RV10-List: Ongoing fuel pressure problems It is not that simple. What pressure you are talking about depends on where in the system you are looking, what brand system you have, etc. In general, the Bendix/Precision style injection system needs about 14-15 psi minimum at the input to the fuel servo. Pressures going to the fuel divider will be lower, and the flow divider shuts down flow at around 4-5 psi to prevent run-on at idle cutoff. The amount of pressure at the inlet is important to have the system function correctly, and to get good atomization at the nozzles. While the engine may run at 9 psi, I'd not be at all comfortable to see below 15. I don't know what pressures the AFS system needs. The Continental system works quite differently and needs very steady and precise pressures at the inlet that have to be checked annually. Kelly Sent from my IBM-360 main frame On Thu, Jun 14, 2018 at 6:06 PM, John MacCallum wrote: > Hi Dan, > From a Video I watched about Fuel Injected engines as long as there is > positive pressure above about 5 PSI at high fuel flows to the FI Servo th e > engine will run fine. The Video was from Tempest Aero parts and it talked > about Engine driven Fuel Pumps and Boost Pumps. The Video was Titled, =9CThe > Amazing Ubiquitous Diaphragm Fuel Pump.=9D > > Anyway the Video said nothing to worry about down to about 9 psi. What > type of boost pump do you have? My Andair Electric boost pump is in the > tunnel and so is the red cube. I have no issues with inaccurate flow > readings but I do occasionally get fuel pressure fluctuations in very hot > weather. That is ambient ground temps above 35 C. I solve this by running > the boost pump until at altitude and the OAT has dropped below 30 C. > > Cheers John MacCallum > VH-DUU > > ________________________________ Message 5 _____________________________________ Time: 10:33:51 PM PST US From: Dan Charrois Subject: Re: RV10-List: Ongoing fuel pressure problems My Lycoming came with an AVStar AVX-5VA1 injector. I'm not sure what "style" of injection that implies (I'm very admittedly not an engine expert). Though in the IO-540 series operator's manual I got with the engine, on page 3-9 they mention a pressure range for the inlet to the fuel injector of 14-45 psi, so I've considered that 14 is a minimum - though I'm much more comfortable when it is closer to 20. When it gets down to less than 14, I get very nervous. Though I've seen it down to 10 psi briefly while the engine kept running, it sure doesn't give me the warm fuzzies when it does that. I have the ES Airflow pump and red cube Van's supplied installed pretty much exactly as described in section 37, other than the exception that I have an Andair fuel valve installed instead of the Van's supplied one. Considering that I've always figured the transducer would have a simple vane system to measure fuel flow, I have to admit to not really understanding how it could be so easily confused by the boost pump upstream (no matter how "pulse-y" it may be)... but it is. Dan > On 2018-Jun-14, at 8:22 PM, Kelly McMullen wrote: > > It is not that simple. What pressure you are talking about depends on where in the system you are looking, what brand system you have, etc. > In general, the Bendix/Precision style injection system needs about 14-15 psi minimum at the input to the fuel servo. Pressures going to the fuel divider will be lower, and the flow divider shuts down flow at around 4-5 psi to prevent run-on at idle cutoff. The amount of pressure at the inlet is important to have the system function correctly, and to get good atomization at the nozzles. While the engine may run at 9 psi, I'd not be at all comfortable to see below 15. > I don't know what pressures the AFS system needs. The Continental system works quite differently and needs very steady and precise pressures at the inlet that have to be checked annually. > Kelly > Sent from my IBM-360 main frame > > On Thu, Jun 14, 2018 at 6:06 PM, John MacCallum wrote: > Hi Dan, > From a Video I watched about Fuel Injected engines as long as there is positive pressure above about 5 PSI at high fuel flows to the FI Servo the engine will run fine. The Video was from Tempest Aero parts and it talked about Engine driven Fuel Pumps and Boost Pumps. The Video was Titled, The Amazing Ubiquitous Diaphragm Fuel Pump. > > Anyway the Video said nothing to worry about down to about 9 psi. What type of boost pump do you have? My Andair Electric boost pump is in the tunnel and so is the red cube. I have no issues with inaccurate flow readings but I do occasionally get fuel pressure fluctuations in very hot weather. That is ambient ground temps above 35 C. I solve this by running the boost pump until at altitude and the OAT has dropped below 30 C. > > Cheers John MacCallum > VH-DUU > > > > > --- Dan Charrois President, Syzygy Research & Technology Phone: 780-961-2213 ________________________________ Message 6 _____________________________________ Time: 10:44:32 PM PST US Subject: Re: RV10-List: Ongoing fuel pressure problems From: Kelly McMullen The one aspect I don't like about the design of the fuel lines in the RV-10 is that they go uphill to the fuel selector, then down to the filter and pump, then back uphill to the firewall and mechanical pump. I believe this forces the system to develop sufficient negative pressure at the mechanical pump to overcome the loop in the fuel system. The Andair with an extension can be mounted fairly low, but is limited by tubing bend radius and lines coming out the bottom. I don't think your fuel cube location should affect the total flow. However the location upstream of the mechanical pump will affect responsiveness. On 6/14/2018 10:31 PM, Dan Charrois wrote: > > My Lycoming came with an AVStar AVX-5VA1 injector. I'm not sure what "style" of injection that implies (I'm very admittedly not an engine expert). Though in the IO-540 series operator's manual I got with the engine, on page 3-9 they mention a pressure range for the inlet to the fuel injector of 14-45 psi, so I've considered that 14 is a minimum - though I'm much more comfortable when it is closer to 20. When it gets down to less than 14, I get very nervous. Though I've seen it down to 10 psi briefly while the engine kept running, it sure doesn't give me the warm fuzzies when it does that. > > I have the ES Airflow pump and red cube Van's supplied installed pretty much exactly as described in section 37, other than the exception that I have an Andair fuel valve installed instead of the Van's supplied one. Considering that I've always figured the transducer would have a simple vane system to measure fuel flow, I have to admit to not really understanding how it could be so easily confused by the boost pump upstream (no matter how "pulse-y" it may be)... but it is. > > Dan > >> On 2018-Jun-14, at 8:22 PM, Kelly McMullen wrote: >> >> It is not that simple. What pressure you are talking about depends on where in the system you are looking, what brand system you have, etc. >> In general, the Bendix/Precision style injection system needs about 14-15 psi minimum at the input to the fuel servo. Pressures going to the fuel divider will be lower, and the flow divider shuts down flow at around 4-5 psi to prevent run-on at idle cutoff. The amount of pressure at the inlet is important to have the system function correctly, and to get good atomization at the nozzles. While the engine may run at 9 psi, I'd not be at all comfortable to see below 15. >> I don't know what pressures the AFS system needs. The Continental system works quite differently and needs very steady and precise pressures at the inlet that have to be checked annually. >> Kelly >> Sent from my IBM-360 main frame >> >> On Thu, Jun 14, 2018 at 6:06 PM, John MacCallum wrote: >> Hi Dan, >> From a Video I watched about Fuel Injected engines as long as there is positive pressure above about 5 PSI at high fuel flows to the FI Servo the engine will run fine. The Video was from Tempest Aero parts and it talked about Engine driven Fuel Pumps and Boost Pumps. The Video was Titled, The Amazing Ubiquitous Diaphragm Fuel Pump. >> >> Anyway the Video said nothing to worry about down to about 9 psi. What type of boost pump do you have? My Andair Electric boost pump is in the tunnel and so is the red cube. I have no issues with inaccurate flow readings but I do occasionally get fuel pressure fluctuations in very hot weather. That is ambient ground temps above 35 C. I solve this by running the boost pump until at altitude and the OAT has dropped below 30 C. >> >> Cheers John MacCallum >> VH-DUU >> >> >> >> >> > > > > --- > Dan Charrois > President, Syzygy Research & Technology > Phone: 780-961-2213 > > > > > ________________________________ Message 7 _____________________________________ Time: 10:55:23 PM PST US Subject: RV10-List: Re: Ongoing fuel pressure problems From: "Bob Turner" My only comment has to do with the totalizer showing a 50% error with the boost pump on. I too have a stock setup, but mine shows a 4% error with the electric pump on. I seem to recall the electric pump has a by-pass with a check valve. Id make sure there are no issues around that pump and its plumbing. -------- Bob Turner RV-10 QB Read this topic online here: http://forums.matronics.com/viewtopic.php?p=480906#480906 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv10-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV10-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/rv10-list Browse Digests http://www.matronics.com/digest/rv10-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.