---------------------------------------------------------- RV-List Digest Archive --- Total Messages Posted Mon 05/21/12: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:01 AM - Re: Exit Fairing (Doug Gray) 2. 07:01 AM - The Original RV-1 Midwest Barnstorming Tour (N8RV@gte.net) 3. 07:15 AM - Re: Exit Fairing (Kelly McMullen) 4. 07:26 AM - Re: Exit Fairing (mr.gsun@gmail.com) 5. 07:51 AM - Re: The Original RV-1 Midwest Barnstorming Tour (Carl Froehlich) 6. 11:07 PM - Re: Exit Fairing (Doug Gray) ________________________________ Message 1 _____________________________________ Time: 06:01:58 AM PST US Subject: Re: RV-List: Exit Fairing From: Doug Gray My #3 CHT is also higher than it should really be - I have been contemplating an addition just like your modification, but I just realized that I have a cabin heater muff on the RHS exhaust pipe. Perhaps this is blocking the airflow from this cylinder. I suppose CHTs to be primarily dependent on power setting and OAT. For day to day comparisons, my EFIS provides good % power analysis in real time (using Kevin Horton's interpolation of the Lycoming performance charts), so I fly my tests at a consistent altitude & same lean % power setting. To compare I normalize the temperatures to an OAT of 25c (77f). For example if the CHT is 360 for an OAT of 60f the temperature differential is 300f; the corrected value I use for any comparison is 377f. This does seem to give comparative results but are there any other factors I should consider? I'm no test pilot, the most difficult part for me is mustering the discipline to take the measurements. Doug Gray Sent from my iPad On 20/05/2012, at 1:30 AM, mr.gsun@gmail.com wrote: > Hey RV posters, In my never ending quest for another ounce of velocity, I installed a cooling air exit fairing at the bottom of the firewall in my RV-7. IO-360. 4 into 2 Vetterman Exhaust pipes. The idea is to straighten the exiting cooling airflow to more closely align with the slipstream. It was one of those easy to install mods that an experienced RV builder told me about. > > It is a curved piece of aluminum about 4" diameter and approximately 10" long. The lower surface is in line with the bottom of the fuselage. A photo is attached. > > The question is: Has anyone installed this sort of thing before? Did you get the same ZERO results? Did it cause increased CHTs? My #3 continues to be too hot but I can't tell if it was affected by this mod. Haven't decided if it is worth removing it. > > Do not archive > ________________________________ Message 2 _____________________________________ Time: 07:01:30 AM PST US From: N8RV@gte.net Subject: RV-List: The Original RV-1 Midwest Barnstorming Tour Richard VanGrunsven's original RV-1 -- yes, the grandaddy of all of our RVs -- is about to begin its Midwest Barnstorming Tour across the I-80/90 corridor. One week from today -- Memorial Day, May 28th -- "The One" will cross over from Canada and clear customs at Toledo Executive Airport (TDZ) in the morning. The Toledo EAA chapter has some events planned for the day (including food, naturally), and then the RV-1 will continue its cross-country tour with a stop at the Mishawaka Pilots' Club (3C1) in Elkhart, IN for fuel and an overnight stop. Next on the tour is Marshall County Airport (C75) in Lacon, IL (near Peoria), then on to Omar Bradley (MBY) in Moberly, MO, on May 29th. If you'd like to see a very significant piece of RV history -- and indeed, aviation history -- with your very eyes, please plan to fly/drive/hitchhike to one of the Barnstorming Tour stops and spend a little time with fellow RVers and enjoy this once-in-a-lifetime opportunity. The RV-1 will end its tour at the EAA Museum in Oshkosh later this year. For more information, please go to www.rv-1.org. -- Don McNamara N8RV ________________________________ Message 3 _____________________________________ Time: 07:15:11 AM PST US From: Kelly McMullen Subject: Re: RV-List: Exit Fairing The main issue with #3 cylinder on 4 cyl Lycomings is that the cyl. head is cast with no cooling fins on the intake port side. Testing on certified aircraft have shown that you do in fact need air passing over that side of the head. Many baffling installations do not leave room for air to get by that side of the head (rear of #3). Providing a 1/8 to 1/4 gap behind the cylinder head can lower the CHT as much as 30 degrees. This can also be an issue on front of #2, depending on baffle design. On 5/21/2012 6:00 AM, Doug Gray wrote: > --> RV-List message posted by: Doug Gray > > My #3 CHT is also higher than it should really be - I have been contemplating an addition just like your modification, but I just realized that I have a cabin heater muff on the RHS exhaust pipe. Perhaps this is blocking the airflow from this cylinder. > > I suppose CHTs to be primarily dependent on power setting and OAT. For day to day comparisons, my EFIS provides good % power analysis in real time (using Kevin Horton's interpolation of the Lycoming performance charts), so I fly my tests at a consistent altitude& same lean % power setting. > > To compare I normalize the temperatures to an OAT of 25c (77f). For example if the CHT is 360 for an OAT of 60f the temperature differential is 300f; the corrected value I use for any comparison is 377f. > > This does seem to give comparative results but are there any other factors I should consider? I'm no test pilot, the most difficult part for me is mustering the discipline to take the measurements. > > Doug Gray > > > Sent from my iPad > > On 20/05/2012, at 1:30 AM, mr.gsun@gmail.com wrote: > >> Hey RV posters, In my never ending quest for another ounce of velocity, I installed a cooling air exit fairing at the bottom of the firewall in my RV-7. IO-360. 4 into 2 Vetterman Exhaust pipes. The idea is to straighten the exiting cooling airflow to more closely align with the slipstream. It was one of those easy to install mods that an experienced RV builder told me about. >> >> It is a curved piece of aluminum about 4" diameter and approximately 10" long. The lower surface is in line with the bottom of the fuselage. A photo is attached. >> >> The question is: Has anyone installed this sort of thing before? Did you get the same ZERO results? Did it cause increased CHTs? My #3 continues to be too hot but I can't tell if it was affected by this mod. Haven't decided if it is worth removing it. >> >> Do not archive >> > > ----- No virus found in this message. Checked by AVG - www.avg.com ________________________________ Message 4 _____________________________________ Time: 07:26:46 AM PST US Subject: Re: RV-List: Exit Fairing From: mr.gsun@gmail.com I put a 1/8" gap behind #3. Now that warmer weather is here, will see if any change occurred. Will also clean injectors soon and try the coke bottle test to see if they are flowing about the same. Not sure what I should be looking for though... Greg On May 21, 2012 7:19 AM, "Kelly McMullen" wrote: > > The main issue with #3 cylinder on 4 cyl Lycomings is that the cyl. head > is cast with no cooling fins on the intake port side. Testing on certified > aircraft have shown that you do in fact need air passing over that side of > the head. Many baffling installations do not leave room for air to get by > that side of the head (rear of #3). Providing a 1/8 to 1/4 gap behind the > cylinder head can lower the CHT as much as 30 degrees. This can also be an > issue on front of #2, depending on baffle design. > > On 5/21/2012 6:00 AM, Doug Gray wrote: > >> --> RV-List message posted by: Doug Gray >> >> My #3 CHT is also higher than it should really be - I have been >> contemplating an addition just like your modification, but I just realized >> that I have a cabin heater muff on the RHS exhaust pipe. Perhaps this is >> blocking the airflow from this cylinder. >> >> I suppose CHTs to be primarily dependent on power setting and OAT. For >> day to day comparisons, my EFIS provides good % power analysis in real time >> (using Kevin Horton's interpolation of the Lycoming performance charts), so >> I fly my tests at a consistent altitude& same lean % power setting. >> >> To compare I normalize the temperatures to an OAT of 25c (77f). For >> example if the CHT is 360 for an OAT of 60f the temperature differential is >> 300f; the corrected value I use for any comparison is 377f. >> >> This does seem to give comparative results but are there any other >> factors I should consider? I'm no test pilot, the most difficult part for >> me is mustering the discipline to take the measurements. >> >> Doug Gray >> >> >> >> Sent from my iPad >> >> On 20/05/2012, at 1:30 AM, mr.gsun@gmail.com wrote: >> >> Hey RV posters, In my never ending quest for another ounce of >>> velocity, I installed a cooling air exit fairing at the bottom of the >>> firewall in my RV-7. IO-360. 4 into 2 Vetterman Exhaust pipes. The >>> idea is to straighten the exiting cooling airflow to more closely align >>> with the slipstream. It was one of those easy to install mods that an >>> experienced RV builder told me about. >>> >>> It is a curved piece of aluminum about 4" diameter and approximately 10" >>> long. The lower surface is in line with the bottom of the fuselage. A >>> photo is attached. >>> >>> The question is: Has anyone installed this sort of thing before? Did >>> you get the same ZERO results? Did it cause increased CHTs? My #3 >>> continues to be too hot but I can't tell if it was affected by this mod. >>> Haven't decided if it is worth removing it. >>> >>> Do not archive >>> >>> >> >> >> >> >> > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > > ________________________________ Message 5 _____________________________________ Time: 07:51:38 AM PST US From: Carl Froehlich Subject: Re: RV-List: The Original RV-1 Midwest Barnstorming Tour I got to see the plane when it stopped at Dogwood (VA42). We'll worth the t ime to see if you can - if nothing else than to grasp how far the current Va n's offerings have evolved. Carl On May 21, 2012, at 10:00 AM, N8RV@gte.net wrote: > Richard VanGrunsven's original RV-1 -- yes, the grandaddy of all of our RV s -- is about to begin its Midwest Barnstorming Tour across the I-80/90 corr idor. One week from today -- Memorial Day, May 28th -- "The One" will cross over from Canada and clear customs at Toledo Executive Airport (TDZ) in the morning. > > The Toledo EAA chapter has some events planned for the day (including food , naturally), and then the RV-1 will continue its cross-country tour with a s top at the Mishawaka Pilots' Club (3C1) in Elkhart, IN for fuel and an overn ight stop. > > Next on the tour is Marshall County Airport (C75) in Lacon, IL (near Peori a), then on to Omar Bradley (MBY) in Moberly, MO, on May 29th. > > If you'd like to see a very significant piece of RV history -- and indeed, aviation history -- with your very eyes, please plan to fly/drive/hitchhike to one of the Barnstorming Tour stops and spend a little time with fellow R Vers and enjoy this once-in-a-lifetime opportunity. The RV-1 will end its t our at the EAA Museum in Oshkosh later this year. > > For more information, please go to www.rv-1.org. > > -- Don McNamara > N8RV > > ========================== ========= ========================== ========= ========================== ========= ========================== ========= > ________________________________ Message 6 _____________________________________ Time: 11:07:49 PM PST US Subject: Re: RV-List: Exit Fairing From: Doug Gray I do have a .062" spacer on the #3 baffle. Doug Sent from my iPad On 22/05/2012, at 12:14 AM, Kelly McMullen wrote: > > The main issue with #3 cylinder on 4 cyl Lycomings is that the cyl. head is cast with no cooling fins on the intake port side. Testing on certified aircraft have shown that you do in fact need air passing over that side of the head. Many baffling installations do not leave room for air to get by that side of the head (rear of #3). Providing a 1/8 to 1/4 gap behind the cylinder head can lower the CHT as much as 30 degrees. This can also be an issue on front of #2, depending on baffle design. > > On 5/21/2012 6:00 AM, Doug Gray wrote: >> --> RV-List message posted by: Doug Gray >> >> My #3 CHT is also higher than it should really be - I have been contemplating an addition just like your modification, but I just realized that I have a cabin heater muff on the RHS exhaust pipe. Perhaps this is blocking the airflow from this cylinder. >> >> I suppose CHTs to be primarily dependent on power setting and OAT. For day to day comparisons, my EFIS provides good % power analysis in real time (using Kevin Horton's interpolation of the Lycoming performance charts), so I fly my tests at a consistent altitude& same lean % power setting. >> >> To compare I normalize the temperatures to an OAT of 25c (77f). For example if the CHT is 360 for an OAT of 60f the temperature differential is 300f; the corrected value I use for any comparison is 377f. >> >> This does seem to give comparative results but are there any other factors I should consider? I'm no test pilot, the most difficult part for me is mustering the discipline to take the measurements. >> >> Doug Gray >> >> >> >> Sent from my iPad >> >> On 20/05/2012, at 1:30 AM, mr.gsun@gmail.com wrote: >> >>> Hey RV posters, In my never ending quest for another ounce of velocity, I installed a cooling air exit fairing at the bottom of the firewall in my RV-7. IO-360. 4 into 2 Vetterman Exhaust pipes. The idea is to straighten the exiting cooling airflow to more closely align with the slipstream. It was one of those easy to install mods that an experienced RV builder told me about. >>> >>> It is a curved piece of aluminum about 4" diameter and approximately 10" long. The lower surface is in line with the bottom of the fuselage. A photo is attached. >>> >>> The question is: Has anyone installed this sort of thing before? Did you get the same ZERO results? Did it cause increased CHTs? My #3 continues to be too hot but I can't tell if it was affected by this mod. Haven't decided if it is worth removing it. >>> >>> Do not archive >>> >> >> >> >> > > > ----- > No virus found in this message. > Checked by AVG - www.avg.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.