---------------------------------------------------------- Pietenpol-List Digest Archive --- Total Messages Posted Tue 02/17/04: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:42 AM - Engine Oil Analysis (KRSBtv@aol.com) 2. 07:29 AM - engine maintenance tips (BARNSTMR@aol.com) 3. 08:53 AM - Re: wind tunnel (Robert Haines) 4. 09:19 AM - Re: Cutting plywood (Alex Sloan) 5. 09:37 AM - Re: Re: wind tunnel (Andimaxd@aol.com) 6. 10:19 AM - Re: Re: wind tunnel (Jim Markle) 7. 01:58 PM - Re: Re: wind tunnel (Christian Bobka) 8. 06:05 PM - Redneck Pilot check-list. (Rcaprd@aol.com) 9. 10:17 PM - Re: Redneck Pilot check-list. (Clif Dawson) 10. 10:38 PM - Re: Redneck Pilot check-list. (Isablcorky@aol.com) ________________________________ Message 1 _____________________________________ Time: 06:42:58 AM PST US From: KRSBtv@aol.com Subject: Pietenpol-List: Engine Oil Analysis I have found an affordable lab for aircraft engine oil analysis. I have been buying oil analysis kits from Aircraft Spruce for the past 15 years, but ACS is pricey. Blackstone Laboratories - 4929 S. Lafayette Street - Fort Wayne, IN 46806 does the analysis for $17. You need to purchase 6 prepaid kits. In my situation, they allowed me to buy 3 kits for an aircraft engine and 3 kits for an automotive engine. They mail you a box containing the kits. They suggest taking the oil sample at midstream. That is to say, you need to let about half of the oil drain out of the sump before acquiring a sample. I've talked to a number of older A&P mechanics (having grown up around airports during my 52 years) and there are several schools of thought in collecting the sample. #1. Take the sample at first stream because the heavier metals are most often found in the first few second of draining the oil and you need to know what the first stream contains. #2. Take the sample while the oil is warm (darned near hot). The logic in this is that everything is stirred up and a hot sample yields the best data as to what is in the oil. #3. Take the sample cold. This logic suggests that after an engine has sat over night, most of the contaminates have found their way down into the sump and this process will provide better data than when gathering a hot sample. #3-B Allow the engine to sit overnight. Place a heat source (such as a floodlight, or clamp a hair dryer aimed at the sump and turn the hair dryer on low) after the oil has warmed up, take the sample at first stream. This is kind of like Let's Make a Deal with Monte Hall. Do you want what's behind Sample 1, Sample 2 or Sample 3? I'm looking forward to seeing debate on this subject... Regardless, Blackstone Labs (260-744-2380_ looks like they are hard to beat when it comes to price. ________________________________ Message 2 _____________________________________ Time: 07:29:57 AM PST US From: BARNSTMR@aol.com Subject: Pietenpol-List: engine maintenance tips The following text is a maintenance Tip on oil content reports from the company where I work, RAM aircraft. See also, the attached pdf file containing all RAM maintenance tips. It may take a while to download, but it will be worthwhile. We publish these tips for our large customer base in the effort to help them maintain their engines to TBO. These tips are the result of more than 30 years overhauling and warranting turbocharged aircraft piston engines. We handle 30+ overahauls a month. ******************* Oil Content Reports: Should I use oil content reports? RAM reminds aircraft operators that one report, especially one deviation from normal report, is not necessarily sufficient reason to become alarmed. There are a number of considerations associated with taking an oil sample as well as preparing the report; plus, there are a number of mechanical considerations associated with estimating engine reliability. Background: Certain parts of both Continental (TCM) and Lycoming engines, such as rocker shafts and piston rings, typically wear and deposit small quantities of normal wear particles in the oil. It is a function of engine design. The Oil Content Report Sample: The quality of the oil sample has a great deal to do with the report. The individual taking the oil sample should use caution not to take the first oil out of the drain, because the majority of the wear metals could have settled to the bottom of the oil pan. Such a procedure could result in an erroneous reading of the metal concentration. In addition, oil samples should only be taken from hot oil. Preferred engine warm-up should be done slowly, beginning at idle RPM for a brief period limiting idle to 1200 RPM. If a dip tube is used, it must not make contact with the bottom of the oil pan where concentrations of wear metals are likely to be exaggerated. RAM recommends engine pre-heat when the OAT is below 20F. How much is too much? What is considered a high concentration of wear metal particles? Remember, an oil content report is measured in parts per million (ppm). Imagine a truck filled with 1,000,000 baseballs. If 20 of them have a flaw it is listed as 20 ppm. Many engines have remained in service through TBO, even though they had one or more abnormal metal particle reports. Recently overhauled engines: Recently overhauled engines may have higher than normal metal particle reports; however, most laboratories are aware of these situations and usually make appropriate adjustments to their reports when so advised of the recent overhaul. ________________________________ Message 3 _____________________________________ Time: 08:53:17 AM PST US From: "Robert Haines" Subject: Pietenpol-List: Re: wind tunnel --> Pietenpol-List message posted by: "Robert Haines" Yea, a wind tunnel does not provide the results you see in the real world. The only exception I can think of is the full scale wind tunnel at Langley where you could actually test a complete airplane. So wind tunnel tests for wing sections or scaled models produce results that provide marginalized information. This usually provides fundamental information to develop a prototype, but the next step is to build the prototype, and then to correct as needed for a production run. The origin of my curiosity for seeking out wind tunnel testing is that it was mentioned that the FC-10 has some unique characteristics, particularly it has a large moment (implying that the center of pressure is aft on the wing). But, there was no documented information on the Cl, Cd, or Cm of this airfoil to verify and quantify these claims. At the same time, there were discussions on the appropriate placement of landing gear, discussions regarding tail volume, discussions regarding trying new wings, and discussions on the moving the wing back or increasing the front of the aircraft. All of this really requires knowledge of the relationships between the CG, center of pressure, and other forces acting on the aircraft. These items seem to be generally known, but nothing (outside of the collected experience of this group) exists that details them. And although simply determining the properties of the FC-10 wing section will not quantitatively answer all of these questions, it will be fundamentally necessary and is a pretty good start. You question was not dumb, actually very insightfull. Unfortuately, there is always error involved when developing information from models (because it's not the actual thing) or sample sets (not all things are exactly the same, but you can't test all things). It then becomes a balance between increasing the detail of testing or moving forward with the current information. Robert "just setting myself up as a target" Haines Du Quoin, Illinois Subject: Pietenpol-List: Re: wind tunnel ================================== Robert and Chris, If I may get in on this discussion, could one of you answer a question that I have regarding airfoil testing and the real world? The tested airfoil is a reproduction of the profile at the rib and yet in the real world the fabric sags somewhat between the ribs therefore changing the profile somewhat. How is this discrepency accounted for in the final results? Or must the test section also incorporate these deformities between the ribs? Just a dumb mechanical engineer trying to get smarter. John ================================== ________________________________ Message 4 _____________________________________ Time: 09:19:17 AM PST US From: "Alex Sloan" Subject: Re: Pietenpol-List: Cutting plywood Pieters, I bought a saw for cutting plywood that goes through like a knife through hot butter. It is a pull saw. I bought it at Lowe's. The name is Shark Saw and they have or can get replacement blades. The blade I have is 19 TPI. I lay it on the line to cut, apply no pressure, just the weight of the saw and PULL it through the line. I have made many cuts on the 1/16" plywood with no splintering. Only time it wanted to flake off was at the end of a cut with a long cut and no support under the unsupported piece. The saw comes with a protective sheath for the teeth. Great tool. Just wanted to share this with the group. Alex Sloan ----- Original Message ----- From: Clif Dawson To: pietenpol-list@matronics.com Sent: Saturday, January 17, 2004 11:21 PM Subject: Re: Pietenpol-List: Cutting plywood Cabinet makers trick-use a knife instead of a pencil. There are knives made especialy for this. They're called "marking knives". Available from all the woodworking catalogue outlets like Lee Valley Tools http://www.leevalley.com/wood/page.asp?SID&ccurrency1&page32502&category1,42936,42949 Garret Wade and others also. A good blade is the 45=B0 one from exacto. Cutting the top layer of fibres limits tearout to that line. Clif ----- Original Message ----- From: dpaul To: pietenpol-list@matronics.com Sent: Saturday, January 17, 2004 10:23 AM Subject: Pietenpol-List: Cutting plywood Listers, Does anyone have a suggestion as to how to cut plywood without pulling up the top layer of ply? Even with new plywood cutting blades I tend to leave a rough edge. I'm ready to make a cut in the rear seat back so it can be hinged for inspection access. I would hate to leave a rough or "over sanded" appearance in a nice looking piece of plywood. Dave in Missouri ________________________________ Message 5 _____________________________________ Time: 09:37:41 AM PST US From: Andimaxd@aol.com Subject: Re: Pietenpol-List: Re: wind tunnel Robert and friends, Don't over analyze this thing, start making saw dust and build it. You guys are beating this dog to death. If you want to reinvent the wheel go ahead...but in the meantime use the search engine, most of these things have been addressed and are archived, if your not too lazy to read old input, which you obviously aren't if you are willing to run all of these tests and calculations. Target acquired, back at ya. In my humble opinion, while you groundlings are still cussing and discussing which is the most efficient design, all the people willing to follow the plans will be flying, albeit a mile or two slower per hour -- but still way over "your" heads !! 75 years, still low and slow... Max, target on his back, Davis Arlington, TX Do not achieve ________________________________ Message 6 _____________________________________ Time: 10:19:27 AM PST US From: Jim Markle Subject: Re: Pietenpol-List: Re: wind tunnel DNA: do not archive Its-Bogus: do not forward to list --- MIME Errors --- A message with no text/plain section was received. The entire body of the message was removed. Please resend the email using plaintext formatting. NOTE! This error can also occur when the poster of the message has a specific type of computer virus. This virus WAS NOT forwarded on to the List. The poster should be informed of the potential problem with their system as soon as possible. --- MIME Errors --- ________________________________ Message 7 _____________________________________ Time: 01:58:16 PM PST US From: "Christian Bobka" Subject: Re: Pietenpol-List: Re: wind tunnel --> Pietenpol-List message posted by: "Christian Bobka" John, that was my question to Robert. I would assume that the test section would have to have all the warts of fabric, rib stitches, etc. to make it valid. chris bobka ----- Original Message ----- From: "John Dilatush" Subject: Re: Pietenpol-List: Re: wind tunnel > > --> Pietenpol-List message posted by: "John Dilatush" > > > ----- Original Message ----- > From: "Robert Haines" > To: > Sent: Monday, February 16, 2004 7:54 AM > Subject: Pietenpol-List: Re: wind tunnel > ================================== > Robert and Chris, > > If I may get in on this discussion, could one of you answer a question that > I have regarding airfoil testing and the real world? > > The tested airfoil is a reproduction of the profile at the rib and yet in > the real world the fabric sags somewhat between the ribs therefore changing > the profile somewhat. How is this discrepency accounted for in the final > results? Or must the test section also incorporate these deformities > between the ribs? > > Just a dumb mechanical engineer trying to get smarter. > John > ================================== > > jPietenpol-List message posted by: "Robert Haines" > > > > Chris, > > > > The SIU wind tunnel is atmospheric with a test section of 24" in width. A > > scale wing I believe would be too small to incorporate detail or an > accurate > > wing section. My inclination is to make a section 6" in cord and the full > > 24" in width. This would be focused toward developing wing section > > information as opposed to a three dimensional study. > > > > Also, I have been working with DesignFOIL and have been in discussion with > > Kevin Holcomb regarding his results with XFoil. Apparently, there is a > lot > > to be desired with low cost (free) wing section analysis software. I have > > results from DesignFOIL, but they are substantially different from the > > XFoil. Suffice it to say that there is a difference in location of the > > center of pressure of over 10% cord for a given angle of attack between > the > > two programs (imagine designing and building an aircraft and finding that > > you have to move the wing 6", not good). > > > > Although I'm an engineer, I don't have any direct experience in wind > tunnel > > tests and would appreciate any suggestions to achieve the most accurate > > results. > > > > > > Robert Haines > > Du Quoin, Illinois > > > > > > > > > > > From: "Christian Bobka" > > > Subject: Pietenpol-List: wind tunnel > > > > > > --> Pietenpol-List message posted by: "Christian Bobka" > > > > > > > > Robert, > > > > > > Sorry to take a while to get back to you on this topic. > > > > > > I would be very interested in seeing a properly executed wind tunnel > > > analysis of the Piet airfoil. This has come up a number of times on > this > > > venue and we never seem to be able to organize well enough to do it. > > > > > > I know Greg Cardinal would like to see it as well as Holcomb and a few > > > others. > > > > > > What chord size and width are you contemplating? Would you make the > > airfoil > > > just like the real one with ribstitches and everything to have the > surface > > > as close to actual as possible? I believe the holcomb's Aerodrome > website > > > has an analysis of the airfoil using one of the canned programs. Does > the > > > wind tunnel at SIU work at MSL density or is it pressurized? > > > > > > Chris Bobka > > > > > > > > > > > > > > > > > > > > > > > > > > ________________________________ Message 8 _____________________________________ Time: 06:05:06 PM PST US From: Rcaprd@aol.com Subject: Pietenpol-List: Redneck Pilot check-list. --> Pietenpol-List message posted by: Rcaprd@aol.com Sorry, I just had to pass this along... Chuck G. A Redneck Pilot check-list. You May be a Redneck Pilot If: 1. Your stall warning plays DIXIE. 2. Your cross-country flight plan uses flea markets as checkpoints. 3. You think sectionals should show trailer parks. 4. You've ever used moonshine as AV-Gas. 5. Your 172's wheel pants have mud flaps with a chrome silhouette of a reclining nude. 6. Your toothpick keeps poking your mike. 7. You've ever taxied around the airport just drinking beer. 8. You wouldn't be caught dead in a Grumman Yankee. 9. You use an old sweet mix sack as a windsock. 10. You constantly confuse "Beechcraft" with "Beechnut." 11. You've never flown a nose-wheel airplane. 12. You refer to formation flying as "We got us a convoy." 13. Your matched set of lightweight flying luggage is 3 grocery bags from Piggly Wiggly. 14. You have a gun rack in the rear window. 15. You have more than one roll of duct tape holding your cowling on. 16. You figure mud and manure in your weight and balance calculations. 17. You siphon gas from your tractor to go flying. 18. You've never landed at an actual airport even though you've been flying for over 20-years. 19. You've ever ground looped to avoid hitting a cow. 20. You consider anything over 500-ft AGL as High Altitude Flying. 21. There are parts on your aircraft labeled "John Deere." 22. You don't own a current sectional, but have all the Texaco road maps for your area. 23. There's a brown streak down each side of your airplane; exhaust on the right side and tobacco on the left. 24. You have to buzz the strip to chase off the livestock before landing. 25. You use an old parachute for a portable hanger. 26. You've ever landed on Main Street for a cup of coffee. 27. The tread pattern, if any, on all three of your tires is different. 28. You have a pair of fuzzy dice and some small copper shoes hanging from the Magnetic Compass. 29. You put straw in the baggage compartment so your dogs don't get cold. 30. You've got matching bumper stickers on each side of the vertical stabilizer. 31. There are grass stains on the tips of your propeller. 32. Somewhere on your plane, there's a bumper sticker that reads "I'd rather be fishing." 33. You navigate with your ADF tuned to only AM country stations. 34. You think an ultra light is a new sissy beer from Budweiser. 35. Just before the crash, everybody on the UNICOM heard you say, "Hey Y'all- Watch This!" ________________________________ Message 9 _____________________________________ Time: 10:17:18 PM PST US From: Clif Dawson Subject: Re: Pietenpol-List: Redneck Pilot check-list. --> Pietenpol-List message posted by: Clif Dawson The John Deere part strikes home to us corvair moonshiners. > A Redneck Pilot check-list. > > You May be a Redneck Pilot If: There are parts on your aircraft labeled "John Deere." ________________________________ Message 10 ____________________________________ Time: 10:38:01 PM PST US From: Isablcorky@aol.com Subject: Re: Pietenpol-List: Redneck Pilot check-list. Ever have a forced in a rice field just prior to harvest? Then see what you do to the farmer on take off. As we say in La, " you talk about "? Do not archive