---------------------------------------------------------- RV-List Digest Archive --- Total Messages Posted Sat 04/22/06: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:16 AM - Re: MT Props delay (dick martin) 2. 04:53 AM - Re: MT Props delay (RV6 Flyer) 3. 06:24 AM - Re: Eustace Bowhay (Emrath) 4. 07:47 AM - Re: Performance Problem Analysis (luckymacy@comcast.net (lucky)) 5. 08:42 AM - Re: Update: Fuel Flow Transducer-Injected (Bob J.) 6. 08:42 AM - Re: AOA & longer wing (was 6a level) (Tracy Crook) 7. 09:01 AM - Re: Performance Problem Analysis (Kevin Horton) 8. 09:13 AM - Re: Performance Problem Analysis (Kyle Boatright) 9. 09:45 AM - Re: Performance Problem Analysis (luckymacy@comcast.net (lucky)) 10. 10:31 AM - Re: Performance Problem Analysis (RV Builder (Michael Sausen)) 11. 10:31 AM - Re: Performance Problem Analysis (RV Builder (Michael Sausen)) 12. 11:02 AM - Re: Performance Problem Analysis (Mickey Coggins) 13. 02:26 PM - Re: Lawsuits against builders (Was AOPA hates homebuilts?) () 14. 10:34 PM - AFP purge valve () ________________________________ Message 1 _____________________________________ Time: 04:16:51 AM PST US From: "dick martin" Subject: Re: RV-List: MT Props delay --> RV-List message posted by: "dick martin" Steve, Suggest you consider a Aero Composites carbon fiber prop. It we be on average 10 knots faster, same weight, has lightning protection, is considerably stronger etc. ad infinitum. Also more expensive, but worth it. Delivery is usually 70 to 90 days. Dick Martin RV8 N233M the fast one ----- Original Message ----- From: "Steve & Denise" Sent: Monday, April 03, 2006 2:29 PM Subject: RV-List: MT Props delay > --> RV-List message posted by: "Steve & Denise" > > Anybody know a faster way to get a MT Prop? > > Van's (MTs) wait time is currently 16 weeks. > > Looking for 2 blade, hydraulic. MTV15B/183-109 > > Steve > RV7A > > > ________________________________ Message 2 _____________________________________ Time: 04:53:16 AM PST US From: "RV6 Flyer" Subject: Re: RV-List: MT Props delay --> RV-List message posted by: "RV6 Flyer" Try another vendor. http://www.lessdrag.com/lycomingpropeller.html Gary A. Sobek "My Sanity" RV-6 N157GS O-320 Hartzell, 1,842 + Flying Hours So. CA, USA http://SoCAL_WVAF.rvproject.com ----Original Message Follows---- From: "dick martin" Subject: Re: RV-List: MT Props delay --> RV-List message posted by: "dick martin" Steve, Suggest you consider a Aero Composites carbon fiber prop. It we be on average 10 knots faster, same weight, has lightning protection, is considerably stronger etc. ad infinitum. Also more expensive, but worth it. Delivery is usually 70 to 90 days. Dick Martin RV8 N233M the fast one ----- Original Message ----- From: "Steve & Denise" Sent: Monday, April 03, 2006 2:29 PM Subject: RV-List: MT Props delay > --> RV-List message posted by: "Steve & Denise" > > Anybody know a faster way to get a MT Prop? > > Van's (MTs) wait time is currently 16 weeks. > > Looking for 2 blade, hydraulic. MTV15B/183-109 > > Steve > RV7A > > > > > > > > > > > > > > > ________________________________ Message 3 _____________________________________ Time: 06:24:18 AM PST US From: "Emrath" Subject: RV-List: Re: Eustace Bowhay --> RV-List message posted by: "Emrath" Konrad, thanks for posting this. Eustace and I never met but we have corresponded via Email and he was very patient and helpful with my questions, even supplying me a much needed part for my FI system. May he rest in Peace and his family be consoled. I'm sorry I cannot be at his service to pay my respects! Do not archive Marty, Brentwood TN Time: 05:21:15 PM PST US From: "Konrad L. Werner" Subject: RV-List: Re: Eustace Bowhay --> RV-List message posted by: "Konrad L. Werner" To Eustace: May you rest in Peace and fly on forever [Ed. This news hurts. The text below appears in this site's Safety section and was written several months back. Eustace was kind enough to host RVTalk #17. He passed away on Tuesday, apparently of complications from a stroke. The RV community has lost one of its giants and our hearts go out to the Bowhay family and friends. By Doug Reeves of www.vansairforce.com] This is for those of you that have never met him, but it is also for the one's that did have the priviledge . . . . "For RV pilots and builders who have never had the opportunity to meet Eustace Bowhay, here=92s a little background. Eustace is one of the few people around who=92ve accumulated over 20,000 hours of flying time without ever having a military or airline career. He spans aviation from before WW2 to the present day. His first flight, as a boy of 10 or 11, was in a Gypsy Moth over his native Saskatchewan. It=92s a great story...Eustace and his mother lived on a farm outside of town, and every weekend the weather permitted they=92d go into the city for supplies and a bit of recreation. He would spend part of his Saturday morning at piano lessons. Nothing in this world was going to make a pianist out of Eustace, but he went to please his mother and because she gave him a quarter so he could go to the movies after his lesson. Eustace soon discovered that the airport on the edge of town was far more interesting to him than any movie, so after his lesson he=92d go down and hang on the fence until it was time to go, just hoping to see an airplane fly. He=92d time it carefully so he could run back to town and meet his mother at the theatre...he knew she=92d never approve of something so dangerous as flying! After a few weeks of this, one of the local pilots on the other side of the fence motioned him over to a hangar and opened the back door. Completely awestruck, Eustace stepped through the door and into what was to become his world for a lifetime. In the hangar was a brand new Staggerwing, painted royal blue. Out in front, a pilot who needed to warm the oil in his Moth invited Eustace to occupy the front cockpit. Stricken to silence by his good fortune, Eustace pulled on a leather helmet and goggles and held on as the upright Gypsy engine rattled the Moth into the air. They flew out over the prairie and over Eustace=92s home. When they returned, Eustace realized he was late meeting his mother and dashed into town, maintaining a minimum altitude of about six inches the whole way. Without comment, he climbed into the car and home they went. At the dinner table that evening, his uncle casually mentioned that an airplane had circled the farm several times earlier in the day. Did Eustace know anything about that? Oh, no, Eustace said. He=92d been at piano lessons and the movies the whole day. Everyone at the table broke into laughter. When his mother handed him a mirror he saw why: the Gypsy had been spraying a fine mist back over the fuselage for the entire flight and the oily outline of the helmet and goggles was clearly printed on his face. He looked like a surprised raccoon. When Eustace tells this story, the memories of that day - more than seventy years ago now - are printed on his face as plainly as the outline of those goggles. He still remembers the smell of the paint and dope on the Staggerwing and the exhilaration of banking and seeing his home between the flying wires of the Moth. After that came flying and more flying. Eustace instructed thousands of students in the RCAF, some of whom died in combat just weeks later - he=92s never fully accepted that waste and a bit of grief is with him still. After the war he instructed thousands more, as well as flying Navions and Aeronca Champs and God knows what else away from the factories and back to Canada. Supported by his wife Nora, he formed his own company, providing charter air service all over the Canada and the Northern Territories. He flew and flew; in Aztec, in Cessnas, in Beavers and Otters. He acquired a P-51 from the Canadian government and flew it all over the country keeping an eye on his operations. He owned and flew a DC-3 for many years. He=92s got 9000+ hours of water operation...1000 hours of it in a Grumman Goose. He=92s landed parts of a bulldozer on the edge of the Arctic Ocean in a Beech 18, helped weld the machine back together and build a landing strip and watched the bulldozer leave, intact, in the hold of a Hercules that flew into the strip to retrieve it. And all the while, one of his primary concerns was keeping other pilots safe. He preached, cajoled, and extolled safe flying at every opportunity, bringing his vast experience to bear and distilling it to benefit the newest of pilots. We will never know just how many pilots are alive (and airplanes unbroken) because Eustace had a word with them, planting some seed of care and awareness that allowed them to avoid danger. He joined the RV ranks in the 1990s by building C-HAY, a 180 hp RV-6 which he flew on wheels, floats and amphibious floats. In the RV community he found many low time pilots venturing into the world of relatively high performance and became their mentor. At the factory, Van=92s people learned to listen carefully to the tall, white haired, slightly deaf Canadian fellow with the suspenders. There was a little "eh?" and a little "oot" in his speech, as well as a whole lot of humanity, wisdom and humor. Eustace and Nora have been to many of Van=92s Homecomings and many RV pilots have met and talked with them. If you=92ve ever had a chance to sit and talk with them, you=92ll have realized that you were in the presence of truly fine people Now recovering from a stroke in his hometown of Salmon Arm, British Columbia, Eustace is still pursuing his passion for helping pilots fly safely and skillfully. It is our incredibly good fortune that he's part of the RV world and that modern technology allows us to essentially sit around the campfire and listen to him pass on knowledge gained over a career that has spanned 70% of powered aviation. Don=92t miss the chance - there aren=92t many like him. Heck, there aren=92t any like him. Eustace is one of a kind." Arrangements (from a Ken Hoshowski email fwd'd to me) Just to let you know that the service gathering for Eustace will be this Saturday at 1:30 at Fischer's Funeral Services, 4060 1st. Ave S.W. Salmon Arm. Toll free phone 1-888-816-1117 This is going to be a tea only, a celebration of life service will be held at a later date in Eustace's home town in Alberta. Eustace's wife's name is Nora and the home address is #6-350 Hudson St. N.W, Salmon Arm B.C., V1E1P4, phone 250 832-3273. That is about all I can tell (you) for now. Ken Hoshowski RV6 C-FKEH Salmon Arm B.C. ________________________________ Message 4 _____________________________________ Time: 07:47:33 AM PST US From: luckymacy@comcast.net (lucky) Subject: Re: RV-List: Performance Problem Analysis --> RV-List message posted by: luckymacy@comcast.net (lucky) WRT James cowl, is it basically just the differently shaped air inlets and their inlet area that make the difference? What's the diameter of the openings? In other words, if one took Van's cowl and redid the openings would that theoretically lower drag?? Or is there a fundamental difference in the air outlet area on the bottom too? Anyone ever take a side by side photos and otherwise do a meaningful compare? Just curious and looking for rainy day projects.... -------------- Original message -------------- From: "dick martin" > --> RV-List message posted by: "dick martin" > > Dave, > I have an RV8 with a James Cowl and plenum and a IO-390 engine. I believe > that it contributes and average speed increase of 10 knots over a standard > Vans cowl. I have over 1300 hours with this set up. I have also talked to > as many others with this set up as possible, and the general consensus is > the same as mine. Also, cooling problems are usually not a problem with > this cowl. > Dick Martin > RV8 N233M > the fast one > ----- Original Message ----- > From: "David Burden" > To: > Sent: Friday, March 24, 2006 8:42 AM > Subject: RV-List: Performance Problem Analysis > > > > --> RV-List message posted by: David Burden > > > > Hello Listers, > > > > I am working through a performance issue and need some help. I need to > > find some folks who have flying aircraft with the following combination of > > features: > > > > Flying RV7a or 9a > > Carburated 180 hp 0360 (Superior/ECI/Lyc) > > Sam James Cowl/plenum/induction system > > Fixed pitch propellor > > > > The intent is to compare some data and discuss any install challenges you > > may have had to overcome with this, apparently rare combination. > > > > Please respond off list to: > > > > hootsnik@sbcglobal.net > > > > Thanks in advance for the help. > > > > Dave > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > WRT James cowl, is it basically just the differently shaped air inlets and their inlet areathat make the difference? What's the diameter of the openings? In other words, if one took Van's cowl and redid the openings would that theoretically lower drag?? Or is there a fundamental difference in the air outlet area on the bottom too? Anyone ever take a side by side photos and otherwise do a meaningful compare? Just curious and looking for rainy day projects.... -------------- Original message -------------- From: "dick martin" martin@gbonline.com -- RV-List message posted by: "dick martin" Dave, I have an RV8 with a James Cowl and plenum and a IO-390 engine. I believe that it contributes and average speed increase of 10 knots over a standard Vans cowl. I have over 1300 hours with this set up. I have also talked to as many others with this set up as possible, and the general consensus is the same as mine. Also, cooling problems are usually not a problem with this cowl. Dick Martin RV8 N233M the fast one ----- Original Message ----- From: "David Burden" To: Sent: Friday, March 24, 2006 8:42 AM Subject: RV-List: Perfor mance Problem Analysis -- RV-List message posted by: David Burden Hello Listers, I am working through a performance issue and need some help. I need to find some folks who have flying aircraft with the following combination of features: Flying RV7a or 9a Carburated 180 hp 0360 (Superior/ECI/Lyc) Sam James Cowl/plenum/induction system Fixed pitch propellor The intent is to compare some data and discuss any install challenges you may have had to overcome with this, apparently rare combination. Please respond off list to: hootsnik@sbcglobal.net Thanks in advance for the help. Dave < BR> hank y ou for your generous support! ________________________________ Message 5 _____________________________________ Time: 08:42:30 AM PST US From: "Bob J." Subject: Re: RV-List: Update: Fuel Flow Transducer-Injected --> RV-List message posted by: "Bob J." Paul, I'm guessing its a Simmonds fuel injection system, in the picture the fuel distributor (spider) is part of the servo. SI1040A is titled "Maintenance procedures applicable to Simmonds #530 fuel injection system." Its a two pager with not much useful info. Regards, Bob Japundza RV-6 flying F1 under const. On 4/21/06, Paul Besing wrote: > > --> RV-List message posted by: Paul Besing > > Thanks, Bob. Yeah, it's definately not a bendix > system, but it works very well...never any vapor lock > and starts on the first blade every time, after 16 > years of service and 800 hours. Can't find anyting in > the logbook regarding maintenance issues. > > Paul Besing > > --- "Bob J." wrote: > > > --> RV-List message posted by: "Bob J." > > > > > > Yep...this is not a bendix system, and the name > > eludes me right now. I have > > seen it before and and the spider and lines are on > > the bottom side as you > > describe. I have service instructions for this type > > of system, if I look it > > up in my foot thick stack of Lycoming service > > instructions I should be able > > to tell you what it is tonight.... > > > > Regards, > > Bob Japundza > > RV-6 flying, F1 under const. > > > > > > On 4/21/06, Paul Besing wrote: > > > > > > --> RV-List message posted by: Paul Besing > > > > > > > > Pardon my ignorance on fuel injections, but here's > > how > > > the routing goes: > > > > > > Fuel out of the firewall to servo. (I'm assuming > > the > > > servo is where the mixture cable plugs into) > > > > > > There are two lines that go from the servo the to > > the > > > divider (the thing on the sump where a carb would > > go, > > > and where the spider is..the spider is on the > > bottom > > > of my engine, not on the top like most). One fuel > > > line to the left side, and one to the right (or > > from > > > one side, as a return) > > > > > > Then there is a third line out of the servo back > > to > > > the fuel selector or tee that fills the left tank. > > > Not sure of the make..there is a data tag on it > > that I > > > briefly read the other day but it wasn't anything > > > familiar. > > > > > > There is a fuel pressure transducer from the > > original > > > installation on one of the lines from the servo to > > the > > > divider, so I'm assuming that's where I'll put my > > fuel flow. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > browse > > Subscriptions page, > > FAQ, > > > > > > Admin. > > > > > > > > > > > > > > > > > > > > > > > > ________________________________ Message 6 _____________________________________ Time: 08:42:30 AM PST US From: "Tracy Crook" Subject: Re: RV-List: AOA & longer wing (was 6a level) --> RV-List message posted by: "Tracy Crook" Thanks to all who answered the AOA question, just the info I needed. There were two reasons for the 3 feet more wing span. Wanted to keep the same (or slightly lower) wing loading as my light RV-4 (now around 920 lbs). Engine will be a 300 HP 3 rotary Mazda 20B. FWF weight will be same as IO - 360 with CS prop. Low stall speed is important to me when doing engine development stuff. The other reason was mission profile. Plane will be used primarily for long distance cruising between here (Florida) and Colorado where the destination airport is at 8000 MSL. Cruise altitude target is 18,000 ft or more where the longer wing will help (I think). The big engine was needed so that ample HP would be available at that altitude. (I hate turbos). Top speed was not a priority and I will never know what it is. My biggest worry is that the longer wing will flutter and self destruct before the engine runs out of steam. Flutter tests to factory redline (230 mph) will be approached with utmost caution. Tracy Crook 13B powered RV-4 - 1550 hrs 20B powered RV-8 - Hangar queen so far --> RV-List message posted by: "Konrad L. Werner" > Hi Tracy, How come you extended your std. RV-8 Wings to become 3ft. longer? Just curious to find out your reason. Do not archive SNIP ...on my "long wing" RV-8. Span is 3 feet longer than stock ... SNIP Tracy Crook -- ________________________________ Message 7 _____________________________________ Time: 09:01:39 AM PST US From: Kevin Horton Subject: Re: RV-List: Performance Problem Analysis --> RV-List message posted by: Kevin Horton On 22 Apr 2006, at 10:41, lucky wrote: > --> RV-List message posted by: luckymacy@comcast.net (lucky) > > WRT James cowl, is it basically just the differently shaped air > inlets and their inlet area that make the difference? What's the > diameter of the openings? In other words, if one took Van's cowl > and redid the openings would that theoretically lower drag?? > > Or is there a fundamental difference in the air outlet area on the > bottom too? > > Anyone ever take a side by side photos and otherwise do a > meaningful compare? > > Just curious and looking for rainy day projects.... Lucky, As I understand it, the performance increase comes from three places: 1. The cowl comes with a plenum chamber, which means more of the air that comes in the inlets actually cools the engine. Baffles leak, so you need to bring in extra air to allow for that leakage. The fact that the plenum chamber has less leakage means less air is needed, so the inlets are smaller. The less air you bring in the inlets, the less cooling drag there is. 2. The contour of the inlet is designed to try to have laminar flow as the air expands, which results in the least amount of drag, and the greatest amount of pressure once the air has expanded. 3. The inlet shape is round. Round inlets have the smallest circumference for a given area, so there is less frictional drag along the walls of the inlet. Any frictional drag results in some pressure loss in the cooling air, which reduces the cooling effectiveness, and means you probably need a bit more air to get the same amount of cooling. This is probably a very minor effect. I believe you could achieve most of the performance increase by having a plenum chamber that has a good seal at the inlet, and reducing the size of the inlets. Many people add plenum chambers, but I believe most of them don't have a good seal at the inlet, so there is quite a bit of leakage there. I also believe that most people don't reduce the size of the inlets. If you don't reduce the size of the inlets, you won't realize any performance increase. Kevin Horton RV-8 (finishing kit) Ottawa, Canada http://www.kilohotel.com/rv8 ________________________________ Message 8 _____________________________________ Time: 09:13:07 AM PST US From: "Kyle Boatright" Subject: Re: RV-List: Performance Problem Analysis --> RV-List message posted by: "Kyle Boatright" Sam James used to sell (and may still sell) round inlets that you can retrofit into your stock cowl. I looked into it when I was building my plane and decided that 1) It would be a lot of work. 2) Even worse, the work would be *serious* fiberglass work. 3) It would be a shame to mess up the nice factory cowling. If I recall correctly, Sam's recommendation was that without a plenum (which he sold), the cowl mod probably wasn't worth the effort. KB ----- Original Message ----- From: "lucky" Sent: Saturday, April 22, 2006 10:41 AM Subject: Re: RV-List: Performance Problem Analysis > --> RV-List message posted by: luckymacy@comcast.net (lucky) > > WRT James cowl, is it basically just the differently shaped air inlets and > their inlet area that make the difference? What's the diameter of the > openings? In other words, if one took Van's cowl and redid the openings > would that theoretically lower drag?? > > Or is there a fundamental difference in the air outlet area on the bottom > too? > > Anyone ever take a side by side photos and otherwise do a meaningful > compare? > > Just curious and looking for rainy day projects.... > -------------- Original message -------------- > From: "dick martin" > >> --> RV-List message posted by: "dick martin" >> >> Dave, >> I have an RV8 with a James Cowl and plenum and a IO-390 engine. I believe >> that it contributes and average speed increase of 10 knots over a >> standard >> Vans cowl. I have over 1300 hours with this set up. I have also talked to >> as many others with this set up as possible, and the general consensus is >> the same as mine. Also, cooling problems are usually not a problem with >> this cowl. >> Dick Martin >> RV8 N233M >> the fast one >> ----- Original Message ----- >> From: "David Burden" >> To: >> Sent: Friday, March 24, 2006 8:42 AM >> Subject: RV-List: Performance Problem Analysis >> >> >> > --> RV-List message posted by: David Burden >> > >> > Hello Listers, >> > >> > I am working through a performance issue and need some help. I need to >> > find some folks who have flying aircraft with the following combination >> > of >> > features: >> > >> > Flying RV7a or 9a >> > Carburated 180 hp 0360 (Superior/ECI/Lyc) >> > Sam James Cowl/plenum/induction system >> > Fixed pitch propellor >> > >> > The intent is to compare some data and discuss any install challenges >> > you >> > may have had to overcome with this, apparently rare combination. >> > >> > Please respond off list to: >> > >> > hootsnik@sbcglobal.net >> > >> > Thanks in advance for the help. >> > >> > Dave >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> >> >> >> >> >> >> >> >> >> >> >> >> > > WRT James cowl, is it basically just the differently shaped air inlets and > their inlet areathat make the difference? What's the diameter of the > openings? In other words, if one took Van's cowl and redid the openings > would that theoretically lower drag?? > > Or is there a fundamental difference in the air outlet area on the bottom > too? > > Anyone ever take a side by side photos and otherwise do a meaningful > compare? > > Just curious and looking for rainy day projects.... > -------------- Original message -------------- > From: "dick martin" martin@gbonline.com > > -- RV-List message posted by: "dick martin" > > Dave, > I have an RV8 with a James Cowl and plenum and a IO-390 engine. I believe > that it contributes and average speed increase of 10 knots over a standard > Vans cowl. I have over 1300 hours with this set up. I have also talked to > as many others with this set up as possible, and the general consensus is > the same as mine. Also, cooling problems are usually not a problem with > this cowl. > Dick Martin > RV8 N233M > the fast one > ----- Original Message ----- > From: "David Burden" > To: > Sent: Friday, March 24, 2006 8:42 AM > Subject: RV-List: > Perfor > mance Problem Analysis > > > -- RV-List message posted by: David Burden > > Hello Listers, > > I am working through a performance issue and need some help. I need to > find some folks who have flying aircraft with the following combination > of > features: > > Flying RV7a or 9a > Carburated 180 hp 0360 (Superior/ECI/Lyc) > Sam James Cowl/plenum/induction system > Fixed pitch propellor > > The intent is to compare some data and discuss any install challenges you > may have had to overcome with this, apparently rare combination. > > Please respond off list to: > > hootsnik@sbcglobal.net > > Thanks in advance for the help. > > Dave > > > < > BR> > > > hank y > ou for your generous support! > > > ________________________________ Message 9 _____________________________________ Time: 09:45:22 AM PST US From: luckymacy@comcast.net (lucky) Subject: Re: RV-List: Performance Problem Analysis --> RV-List message posted by: luckymacy@comcast.net (lucky) Any engineers out there care to hazard a guess what the percentage of gain is for each of the 3 referenced sources? ie, for the 10 knot gain in using the Sam James setup, 70% from the combo of the smaller area openings and use of a integrated/sealed plenum and 30 percent from exterior cowl shape? If it was the other way around, I wouldn't even consider it a worthwhile project.... -------------- Original message -------------- From: Kevin Horton > --> RV-List message posted by: Kevin Horton > > On 22 Apr 2006, at 10:41, lucky wrote: > > > --> RV-List message posted by: luckymacy@comcast.net (lucky) > > > > WRT James cowl, is it basically just the differently shaped air > > inlets and their inlet area that make the difference? What's the > > diameter of the openings? In other words, if one took Van's cowl > > and redid the openings would that theoretically lower drag?? > > > > Or is there a fundamental difference in the air outlet area on the > > bottom too? > > > > Anyone ever take a side by side photos and otherwise do a > > meaningful compare? > > > > Just curious and looking for rainy day projects.... > > > Lucky, > > As I understand it, the performance increase comes from three places: > > 1. The cowl comes with a plenum chamber, which means more of the air > that comes in the inlets actually cools the engine. Baffles leak, so > you need to bring in extra air to allow for that leakage. The fact > that the plenum chamber has less leakage means less air is needed, so > the inlets are smaller. The less air you bring in the inlets, the > less cooling drag there is. > > 2. The contour of the inlet is designed to try to have laminar flow > as the air expands, which results in the least amount of drag, and > the greatest amount of pressure once the air has expanded. > > 3. The inlet shape is round. Round inlets have the smallest > circumference for a given area, so there is less frictional drag > along the walls of the inlet. Any frictional drag results in some > pressure loss in the cooling air, which reduces the cooling > effectiveness, and means you probably need a bit more air to get the > same amount of cooling. This is probably a very minor effect. > > I believe you could achieve most of the performance increase by > having a plenum chamber that has a good seal at the inlet, and > reducing the size of the inlets. Many people add plenum chambers, > but I believe most of them don't have a good seal at the inlet, so > there is quite a bit of leakage there. I also believe that most > people don't reduce the size of the inlets. If you don't reduce the > size of the inlets, you won't realize any performance increase. > > Kevin Horton RV-8 (finishing kit) > Ottawa, Canada > http://www.kilohotel.com/rv8 > > > > > > > > > > > > > Any engineers out there care to hazard a guess what the percentage of gain is for each of the 3 referenced sources? ie, for the 10 knot gain in using the Sam James setup, 70% from the combo of the smaller area openings and use of a integrated/sealed plenum and 30 percent from exterior cowl shape? If it was the other way around, I wouldn't even consider it a worthwhile project.... -------------- Original message -------------- From: Kevin Horton khorton01@rogers.com -- RV-List message posted by: Kevin Horton On 22 Apr 2006, at 10:41, lucky wrote: -- RV-List message posted by: luckymacy@comcast.net (lucky) WRT James cowl, is it basically just the differently shaped air inlets and their inlet area that make the difference? What's the diameter of the openings? In other words, if one took Van's cowl and redid the openings would that theoretically lower drag?? Or is there a fundamental difference in the air outlet area on the bottom too? Anyone ever take a side by side photos and otherwise do a meaningful compare? &g t;
Just curious and looking for rainy day projects.... Lucky, As I understand it, the performance increase comes from three places: 1. The cowl comes with a plenum chamber, which means more of the air that comes in the inlets actually cools the engine. Baffles leak, so you need to bring in extra air to allow for that leakage. The fact that the plenum chamber has less leakage means less air is needed, so the inlets are smaller. The less air you bring in the inlets, the less cooling drag there is. 2. The contour of the inlet is designed to try to have laminar flow as the air expands, which results in the least amount of drag, and the greatest amount of pressure once the air has expanded. 3. The inlet shape is round. Round inlets have the smallest circumference for a given area, so there is less frictio nal dr ag along the walls of the inlet. Any frictional drag results in some pressure loss in the cooling air, which reduces the cooling effectiveness, and means you probably need a bit more air to get the same amount of cooling. This is probably a very minor effect. I believe you could achieve most of the performance increase by having a plenum chamber that has a good seal at the inlet, and reducing the size of the inlets. Many people add plenum chambers, but I believe most of them don't have a good seal at the inlet, so there is quite a bit of leakage there. I also believe that most people don't reduce the size of the inlets. If you don't reduce the size of the inlets, you won't realize any performance increase. Kevin Horton RV-8 (finishing kit) Ottawa, Canada http://www.kilohotel.com/rv8 ====== ================================================= &g t;
________________________________ Message 10 ____________________________________ Time: 10:31:39 AM PST US Subject: RE: RV-List: Performance Problem Analysis From: "RV Builder (Michael Sausen)" --> RV-List message posted by: "RV Builder (Michael Sausen)" From what I have been told most of it is from a combination of streamlining the inlets, reducing their size, and from pressure recovery. The plenum helps but is mainly to manage the cooling. Michael Sausen -10 #352 Fuselage Do not archive -----Original Message----- From: owner-rv-list-server@matronics.com [mailto:owner-rv-list-server@matronics.com] On Behalf Of lucky Sent: Saturday, April 22, 2006 11:39 AM Subject: Re: RV-List: Performance Problem Analysis --> RV-List message posted by: luckymacy@comcast.net (lucky) Any engineers out there care to hazard a guess what the percentage of gain is for each of the 3 referenced sources? ie, for the 10 knot gain in using the Sam James setup, 70% from the combo of the smaller area openings and use of a integrated/sealed plenum and 30 percent from exterior cowl shape? If it was the other way around, I wouldn't even consider it a worthwhile project.... -------------- Original message -------------- From: Kevin Horton > --> RV-List message posted by: Kevin Horton > > On 22 Apr 2006, at 10:41, lucky wrote: > > > --> RV-List message posted by: luckymacy@comcast.net (lucky) > > > > WRT James cowl, is it basically just the differently shaped air > > inlets and their inlet area that make the difference? What's the > > diameter of the openings? In other words, if one took Van's cowl and > > redid the openings would that theoretically lower drag?? > > > > Or is there a fundamental difference in the air outlet area on the > > bottom too? > > > > Anyone ever take a side by side photos and otherwise do a meaningful > > compare? > > > > Just curious and looking for rainy day projects.... > > > Lucky, > > As I understand it, the performance increase comes from three places: > > 1. The cowl comes with a plenum chamber, which means more of the air > that comes in the inlets actually cools the engine. Baffles leak, so > you need to bring in extra air to allow for that leakage. The fact > that the plenum chamber has less leakage means less air is needed, so > the inlets are smaller. The less air you bring in the inlets, the less > cooling drag there is. > > 2. The contour of the inlet is designed to try to have laminar flow as > the air expands, which results in the least amount of drag, and the > greatest amount of pressure once the air has expanded. > > 3. The inlet shape is round. Round inlets have the smallest > circumference for a given area, so there is less frictional drag along > the walls of the inlet. Any frictional drag results in some pressure > loss in the cooling air, which reduces the cooling effectiveness, and > means you probably need a bit more air to get the same amount of > cooling. This is probably a very minor effect. > > I believe you could achieve most of the performance increase by having > a plenum chamber that has a good seal at the inlet, and reducing the > size of the inlets. Many people add plenum chambers, but I believe > most of them don't have a good seal at the inlet, so there is quite a > bit of leakage there. I also believe that most people don't reduce the > size of the inlets. If you don't reduce the size of the inlets, you > won't realize any performance increase. > > Kevin Horton RV-8 (finishing kit) > Ottawa, Canada > http://www.kilohotel.com/rv8 > > Any engineers out there care to hazard a guess what the percentage of gain is for each of the 3 referenced sources? ie, for the 10 knot gain in using the Sam James setup, 70% from the combo of the smaller area openings and use of a integrated/sealed plenum and 30 percent from exterior cowl shape? If it was the other way around, I wouldn't even consider it a worthwhile project.... -------------- Original message -------------- From: Kevin Horton khorton01@rogers.com -- RV-List message posted by: Kevin Horton On 22 Apr 2006, at 10:41, lucky wrote: -- RV-List message posted by: luckymacy@comcast.net (lucky) WRT James cowl, is it basically just the differently shaped air inlets and their inlet area that make the difference? What's the diameter of the openings? In other words, if one took Van's cowl and redid the openings would that theoretically lower drag?? Or is there a fundamental difference in the air outlet area on the bottom too? Anyone ever take a side by side photos and otherwise do a meaningful compare? &g t;
Just curious and looking for rainy day projects.... Lucky, As I understand it, the performance increase comes from three places: 1. The cowl comes with a plenum chamber, which means more of the air that comes in the inlets actually cools the engine. Baffles leak, so you need to bring in extra air to allow for that leakage. The fact that the plenum chamber has less leakage means less air is needed, so the inlets are smaller. The less air you bring in the inlets, the less cooling drag there is. 2. The contour of the inlet is designed to try to have laminar flow as the air expands, which results in the least amount of drag, and the greatest amount of pressure once the air has expanded. 3. The inlet shape is round. Round inlets have the smallest circumference for a given area, so there is less frictio nal dr ag along the walls of the inlet. Any frictional drag results in some pressure loss in the cooling air, which reduces the cooling effectiveness, and means you probably need a bit more air to get the same amount of cooling. This is probably a very minor effect. I believe you could achieve most of the performance increase by having a plenum chamber that has a good seal at the inlet, and reducing the size of the inlets. Many people add plenum chambers, but I believe most of them don't have a good seal at the inlet, so there is quite a bit of leakage there. I also believe that most people don't reduce the size of the inlets. If you don't reduce the size of the inlets, you won't realize any performance increase. Kevin Horton RV-8 (finishing kit) Ottawa, Canada http://www.kilohotel.com/rv8 =3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D &g t;
________________________________ Message 11 ____________________________________ Time: 10:31:39 AM PST US Subject: RE: RV-List: Performance Problem Analysis From: "RV Builder (Michael Sausen)" --> RV-List message posted by: "RV Builder (Michael Sausen)" Kevin pretty much hit it on the head. You are looking for a couple of things in a cowl. One is to have easy bends for the inlet and outlet air to pass through so you are not imparting much of the airflow's energy into the airframe (more drag). Also you want the best pressure recovery ratio you can get. Essentially whatever the pressure is of the air entering the cowl you want to try and make it the same number as it exits. Any deviation from 1 to 1 will cause drag and/or cooling problems. You then use the venturi effect to either slow or speed up the airflow inside the cowling to increase or decrease the amount of heat transfer from the engine. These two areas are where the James cowl makes the difference. Michael Sausen -10 #352 Fuselage -----Original Message----- From: owner-rv-list-server@matronics.com [mailto:owner-rv-list-server@matronics.com] On Behalf Of Kevin Horton Sent: Saturday, April 22, 2006 10:57 AM Subject: Re: RV-List: Performance Problem Analysis --> RV-List message posted by: Kevin Horton On 22 Apr 2006, at 10:41, lucky wrote: > --> RV-List message posted by: luckymacy@comcast.net (lucky) > > WRT James cowl, is it basically just the differently shaped air inlets > and their inlet area that make the difference? What's the diameter of > the openings? In other words, if one took Van's cowl and redid the > openings would that theoretically lower drag?? > > Or is there a fundamental difference in the air outlet area on the > bottom too? > > Anyone ever take a side by side photos and otherwise do a meaningful > compare? > > Just curious and looking for rainy day projects.... Lucky, As I understand it, the performance increase comes from three places: 1. The cowl comes with a plenum chamber, which means more of the air that comes in the inlets actually cools the engine. Baffles leak, so you need to bring in extra air to allow for that leakage. The fact that the plenum chamber has less leakage means less air is needed, so the inlets are smaller. The less air you bring in the inlets, the less cooling drag there is. 2. The contour of the inlet is designed to try to have laminar flow as the air expands, which results in the least amount of drag, and the greatest amount of pressure once the air has expanded. 3. The inlet shape is round. Round inlets have the smallest circumference for a given area, so there is less frictional drag along the walls of the inlet. Any frictional drag results in some pressure loss in the cooling air, which reduces the cooling effectiveness, and means you probably need a bit more air to get the same amount of cooling. This is probably a very minor effect. I believe you could achieve most of the performance increase by having a plenum chamber that has a good seal at the inlet, and reducing the size of the inlets. Many people add plenum chambers, but I believe most of them don't have a good seal at the inlet, so there is quite a bit of leakage there. I also believe that most people don't reduce the size of the inlets. If you don't reduce the size of the inlets, you won't realize any performance increase. Kevin Horton RV-8 (finishing kit) Ottawa, Canada http://www.kilohotel.com/rv8 ________________________________ Message 12 ____________________________________ Time: 11:02:16 AM PST US From: Mickey Coggins Subject: Re: RV-List: Performance Problem Analysis --> RV-List message posted by: Mickey Coggins > Any engineers out there care to hazard a guess what the percentage of > gain is for each of the 3 referenced sources? > > ie, for the 10 knot gain in using the Sam James setup, 70% from the > combo of the smaller area openings and use of a integrated/sealed > plenum and 30 percent from exterior cowl shape? The cowl shape has got to be a lot. It is much smaller at the front, and since it is 4 inches longer, the transition to the full fuselage is much smoother. They have some pics on their website that kind of show what I mean: http://www.jamesaircraft.com/Our_Products.html However, when you see it in person, compared to the standard Van's cowl, the difference is striking. -- Mickey Coggins http://www.rv8.ch/ #82007 finishing do not archive ________________________________ Message 13 ____________________________________ Time: 02:26:00 PM PST US From: Subject: RV-List: Re: Lawsuits against builders (Was AOPA hates homebuilts?) --> RV-List message posted by: Dan: I talked to my aviation lawyer less than a year ago and my info, John Denver's estate did not sue the builder. It would be ridiculous a multimillionaire (estate) suing a guy with $2 in the bank. Please send your source/ refrence. God rest his soul, Dear John was flying real low on altitude and gas, and had no license after a few DWI's. I think you are wrong. (John Denver flew into the water. The fuel selector was in a non-standard place and was thought that he accidentally flew into the water when reaching for it. However he was very low and was out or almost out of fuel. Lesson learned BUILD YOU RV PER PLANS and DON'T DO WEIRD ONE OFF SYSTEM DESIGNS YOU DREAM UP, at least if you don't want to be suied.) Your case TWO. Again no offense but facts, case number, names, not rumor, hearsay and urban legend. This is what I am talking about. You throw out a scenario that is hard to believe, no offense. I would not be surprised if someone at AOPA made this up. There have been people's estates who sue the pilot or pilot estate for killing the passenger, their family member, but that has NOTHING to do with selling a plane and being sued as the builder or manufacture. (BY THE WAY, waiver and hold harmless waivers work for passengers. Whether the hold up how know it would no hurt. ALSO have a LAWYER write these up. It is worth the few $100 bucks to have it written verses a generic boiler-plate form you found or dreamed up.) If you have examples: Names, places, state, city where the lawsuit is filed I'll look into it. I still stand by NEVER. Your other points and conjecture is correct and interesting. Yes lawsuits are expensive even if you win. However put that into the agreement. The agreement says if you buy and fly this home-built you can DIE, you accept all risk and waive all legal rights to sue, you the builder. If you do get sued from some 3rd party (a passenger) the buyer will pay all your legal fees. That is the way it should be anyway. That would cut down the stupid frivolous lawsuits. As I said these agreements should work but there is no legal precedence, since no builder has been sued for building (that I or my aviation lawyer knows of). It is better than nothing. CAN YOU BE SUED. you bet your sweat rudder you can. However as I said your dog bites someone you can get suied. Build a good plane, don't sell to an idiot, get a waiver drawn up by a Lawyer and allow or insist that the buyers faimly and their lawyer read and approve it. If for some reason you got sued the defense should not break the bank. Slam dunk, the buyer killed them self for say, doing low level acro. Cheers George >From: "Dan Morrow" >Subject: Re: RV-List: Re: AOPA hates homebuilts? > >posted by: "Dan Morrow" > >"Never" is a big word. I can think of two lawsuits against builders >just from casual reading of the news in the last few years. >Lawsuit 1: In the John Denver crash, the newspapers reported that >Denver's relatives sued several people including the builder. I don't >know the outcome however. > >Lawsuit 2: This one was somewhat complicated involving several sales >and owners. Step 1: Individual A builds aircraft and flies for several >years. Sells aircraft to individual B. >Step 2: B flies aircraft for several years and then sells aircraft >to individual C. Step 3: C flies aircraft for several years. Then one >day he takes a friend's wife for a ride and performs low level aerobatics >in view of the husband. Crashes killing himself and friend's wife. >Step 4: Husband sues individual A. >Step 5: Individual A sues B. I don't know the outcome of the >lawsuits. --------------------------------- ________________________________ Message 14 ____________________________________ Time: 10:34:16 PM PST US From: Subject: RV-List: AFP purge valve --> RV-List message posted by: Howdy Thought I would share with the list the folowing question I e-mailed to Airflow Performance and their reply: "I have one of your fuel injection units on my new IO-360 B1B engine and RV-7A aircraft. It would seem prudent to have a spring or other similar device on the purge valve control arm to insure that if the cable controlling the pure valve were to fail, the control arm would remain in the normal run position. Do you agree, and if so, do you offer a product for this purpose? If not, perhaps you have some suggestions for obtaining or fabricating such a device?" Here is the replay that I received: "We typically recommend that the system is installed with good quality cables with rod ends. This should eliminate any need for return springs. I always ask; "Did you put a return spring on the mixture control or throttle?" But of course the choice is yours. If you feel a return spring on the purge valve will give you piece of mind, by all means do it. I have seen some installations use a simple extension spring connected to the purge valve lever to a adel clamp on a push rod tube to pull the lever to the run position." Don Rivera Airflow Performance