---------------------------------------------------------- Pietenpol-List Digest Archive --- Total Messages Posted Wed 01/25/17: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:56 AM - Re: Re: Long fuselage and Model A (JERRY) 2. 04:59 AM - Re: Re: Long fuselage and Model A (JERRY) 3. 09:48 PM - Re: Long fuselage and Model A (taildrags) ________________________________ Message 1 _____________________________________ Time: 04:56:38 AM PST US From: "JERRY" Subject: RE: Pietenpol-List: Re: Long fuselage and Model A Thanks again Oscar I am sure I can figure it out. I too think that I have an one-off fuselage were most if not all of the added length is in the nose. I will have to do a W & B calculation but I am betting that I will have to move the wing forward a little and place the Model A or B engine as far back as possible. Also I can lose some weight up front with an aluminum head and maybe some other mods. It will help that I am 220 lbs. Also I have found that the gear are totally junk as over half of the main tube was rusted through. So I will have to make new gear. So I can get it placed where I want it. I have not emailed Bob yet but will do that today. I do have a picture working on the wing on the Pietenpol facebook group with my grandson. He comes over every Thursday night to help or me help him I am not sure. It forces me to have something ready for him to work on so the plane is coming along nicely. -----Original Message----- From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of taildrags Sent: Tuesday, January 24, 2017 10:59 PM Subject: Pietenpol-List: Re: Long fuselage and Model A --> Jerry; it looks like what you've got there is a one-off variant. For your information, here's a snip from a very thorough dissertation on Piet fuselage length variations by Chris Bobka, from around 2004. He's responding to a question from builder Walt Evans and it has to do with the axle location because that's pretty important to how the airplane will handle on the ground, but look past some of that to see the information on some key dimensions. Get a piece of scratch paper and a pencil and sketch it out. You might check some other dimensions on your airframe, but you may very likely have a hermaphrodite there... but not unprecedented. And by the way, Walt Evans built and flew his absolutely gorgeous Air Camper successfully, and you can see pictures of it on the Westcoastpiet.com site. Here's one such picture: http://www.westcoastpiet.com/images/WB%20Evans/images/1200Fly.jpg Note that Chris refers to a "Pavliga long fuselage" (Frank Pavliga, a legend in the Piet world)- with a fuselage of 172.375" long. If I've added up the numbers in your sketch correctly, your fuselage is 172" long, so there is at least one other airplane out there flying with a fuselage that is within 3/8" of being the same length as yours and Pavliga's. Not to worry though... the laws of physics still apply, which means that one or more of the very useful CG calculation spreadsheets out there will help you build and fly a safe airplane. We put men on the moon with nothing more than slide rules... so anything is possible if you have a spreadsheet. Here's some reading for you, snipped from the archives. ================ The 1932 fuselage (Hoopman drawings and 1932 Flying and Glider Manual) is 161 inches long. The 1933 Improved Air Camper fuselage is 163 inches long. The Pavliga long fuselage is 172.375 inches long. This is the one I understand you have built. It appears that the intersection of the first truss verticals with the lower longeron on the 1932 fuselage is 8.375 or 8.5 inches aft of the firewall, depending on which set of plans you look at. On the 1933 Improved fuselage, it is 10 inches, and on the Pavliga long fuselage, it is 12 inches. This would mean that the wood gear, unmodified from the 1932 plans and as mounted on the Pavliga long fuselage, would put the axle 12-8.5 or 3.5 inches farther aft on the long fuselage than on the 1932 fuselage. It would be at 13.5 (see paragraph 1 sentence 1) + 3.5 or 17 inches aft of the firewall. Is this a good place for it? Frank P. said it was too far forward at 17 inches aft of the firewall so he moved it aft when he did the engine switch. A better indicator of proper gear position is comparing it to the rear seat back position in the particular fuselage since this indicates the shift aft of the CG position as the fuselages have been stretched. The rear seat back (at the top longeron) in the 1932 fuselage is 70.5 inches aft of the firewall. The rear seat back in the 1933 Improved fuselage is 72.25 inches aft of the firewall. The rear seat back of the Pavliga long fuselage is 76.25 inches aft of the firewall. This is a substantial shift aft in the position of the CG versus the axle position as the fuselage is stretched. Therefore, the axle on the 1932 fuselage is 70.5 -13.5 or 57 inches forward of the rear seat back. The axle on the 1933 Improved is 72.25 -17 or 55.25 inches forward of the rear seat back. Let us ignore the value from the 1932 fuselage for reasons to be discussed later. Using the number from 1933 and applying this to the Pavliga long fuselage, we should have the axle at 76.25 - 55.25 or 21 inches aft of the firewall. Two paragraphs ago we determined that it will actually wind up at 17 inches aft of the firewall with the wood gear, unmodified, and Frank P. says this is too far forward. Therefore, it appears that we need to redesign the gear so that the axle will sit farther aft in the V to the tune of about 21 -17 or 4 inches. As we noted above, if you look at the sweep of the V in the 1932 plans, you will note that the front attach of the V is at 8.5 inches aft of the firewall. We know that the axle is about 13.5 inches aft of the firewall. Therefore, the sweep is 13.5 - 8.5 or 5 inches for the wood gear. Doing the same analysis for the 1933 Improved Air Camper, we know the front attach of the V is at 10 inches aft of the firewall and the axle is at 17 inches aft of the firewall. Therefore the sweep is 17 -10 or 7 inches for the split axle gear. The next sentence is important. If you put the 1932 wood gear on a 1933 Improved fuselage, you would have an axle that will be 7 - 5 or 2 inches forward of where it would have been if you had used the split axle gear!!!! So the gears are not necessarily interchangeable!!! Logic says that it does not matter which style gear you use. The axle should always be in the same relative position. I see this as an admission by BP that the original 1932 axle was too far forward by 2 inches. And now we know what Frank P. was talking about!!!! It is obvious that BP saw fit, when designing the 1933 Improved Air Camper, that if he lengthened the fuselage from 161 to 163 inches and moved the pilot's rear seat back aft by 1.75 inches, then he must move the axle aft by 17 -13.5 - 2 or 1.5 inches. (Consider 2 of the 3.5 inch difference between 17 and 13.5 as a design correction and the remaining 1.5 of the 3.5 inches to be an adjustment for the new fuselage length and movement aft of the rear seat back.) So what would BP do if he made the fuselage 172.375 inches long (a whopping 9.375 inches longer) and moved the rear seat back aft yet another 76.25 -72.25 or 4 inches? -------- Oscar Zuniga Medford, OR Air Camper NX41CC "Scout" A75 power, 72x36 Culver prop Read this topic online here: http://forums.matronics.com/viewtopic.php?p=465417#465417 ----- No virus found in this message. Checked by AVG - www.avg.com ________________________________ Message 2 _____________________________________ Time: 04:59:26 AM PST US From: "JERRY" Subject: RE: Pietenpol-List: Re: Long fuselage and Model A Oops I should have thanked taildrags. I have been up to the fly inn a couple time with Jack Textor bet did not talk to many people there. Someday I hope to fly it up there. Thanks very much for the help. Jerry -----Original Message----- From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of taildrags Sent: Tuesday, January 24, 2017 10:59 PM Subject: Pietenpol-List: Re: Long fuselage and Model A --> Jerry; it looks like what you've got there is a one-off variant. For your information, here's a snip from a very thorough dissertation on Piet fuselage length variations by Chris Bobka, from around 2004. He's responding to a question from builder Walt Evans and it has to do with the axle location because that's pretty important to how the airplane will handle on the ground, but look past some of that to see the information on some key dimensions. Get a piece of scratch paper and a pencil and sketch it out. You might check some other dimensions on your airframe, but you may very likely have a hermaphrodite there... but not unprecedented. And by the way, Walt Evans built and flew his absolutely gorgeous Air Camper successfully, and you can see pictures of it on the Westcoastpiet.com site. Here's one such picture: http://www.westcoastpiet.com/images/WB%20Evans/images/1200Fly.jpg Note that Chris refers to a "Pavliga long fuselage" (Frank Pavliga, a legend in the Piet world)- with a fuselage of 172.375" long. If I've added up the numbers in your sketch correctly, your fuselage is 172" long, so there is at least one other airplane out there flying with a fuselage that is within 3/8" of being the same length as yours and Pavliga's. Not to worry though... the laws of physics still apply, which means that one or more of the very useful CG calculation spreadsheets out there will help you build and fly a safe airplane. We put men on the moon with nothing more than slide rules... so anything is possible if you have a spreadsheet. Here's some reading for you, snipped from the archives. ================ The 1932 fuselage (Hoopman drawings and 1932 Flying and Glider Manual) is 161 inches long. The 1933 Improved Air Camper fuselage is 163 inches long. The Pavliga long fuselage is 172.375 inches long. This is the one I understand you have built. It appears that the intersection of the first truss verticals with the lower longeron on the 1932 fuselage is 8.375 or 8.5 inches aft of the firewall, depending on which set of plans you look at. On the 1933 Improved fuselage, it is 10 inches, and on the Pavliga long fuselage, it is 12 inches. This would mean that the wood gear, unmodified from the 1932 plans and as mounted on the Pavliga long fuselage, would put the axle 12-8.5 or 3.5 inches farther aft on the long fuselage than on the 1932 fuselage. It would be at 13.5 (see paragraph 1 sentence 1) + 3.5 or 17 inches aft of the firewall. Is this a good place for it? Frank P. said it was too far forward at 17 inches aft of the firewall so he moved it aft when he did the engine switch. A better indicator of proper gear position is comparing it to the rear seat back position in the particular fuselage since this indicates the shift aft of the CG position as the fuselages have been stretched. The rear seat back (at the top longeron) in the 1932 fuselage is 70.5 inches aft of the firewall. The rear seat back in the 1933 Improved fuselage is 72.25 inches aft of the firewall. The rear seat back of the Pavliga long fuselage is 76.25 inches aft of the firewall. This is a substantial shift aft in the position of the CG versus the axle position as the fuselage is stretched. Therefore, the axle on the 1932 fuselage is 70.5 -13.5 or 57 inches forward of the rear seat back. The axle on the 1933 Improved is 72.25 -17 or 55.25 inches forward of the rear seat back. Let us ignore the value from the 1932 fuselage for reasons to be discussed later. Using the number from 1933 and applying this to the Pavliga long fuselage, we should have the axle at 76.25 - 55.25 or 21 inches aft of the firewall. Two paragraphs ago we determined that it will actually wind up at 17 inches aft of the firewall with the wood gear, unmodified, and Frank P. says this is too far forward. Therefore, it appears that we need to redesign the gear so that the axle will sit farther aft in the V to the tune of about 21 -17 or 4 inches. As we noted above, if you look at the sweep of the V in the 1932 plans, you will note that the front attach of the V is at 8.5 inches aft of the firewall. We know that the axle is about 13.5 inches aft of the firewall. Therefore, the sweep is 13.5 - 8.5 or 5 inches for the wood gear. Doing the same analysis for the 1933 Improved Air Camper, we know the front attach of the V is at 10 inches aft of the firewall and the axle is at 17 inches aft of the firewall. Therefore the sweep is 17 -10 or 7 inches for the split axle gear. The next sentence is important. If you put the 1932 wood gear on a 1933 Improved fuselage, you would have an axle that will be 7 - 5 or 2 inches forward of where it would have been if you had used the split axle gear!!!! So the gears are not necessarily interchangeable!!! Logic says that it does not matter which style gear you use. The axle should always be in the same relative position. I see this as an admission by BP that the original 1932 axle was too far forward by 2 inches. And now we know what Frank P. was talking about!!!! It is obvious that BP saw fit, when designing the 1933 Improved Air Camper, that if he lengthened the fuselage from 161 to 163 inches and moved the pilot's rear seat back aft by 1.75 inches, then he must move the axle aft by 17 -13.5 - 2 or 1.5 inches. (Consider 2 of the 3.5 inch difference between 17 and 13.5 as a design correction and the remaining 1.5 of the 3.5 inches to be an adjustment for the new fuselage length and movement aft of the rear seat back.) So what would BP do if he made the fuselage 172.375 inches long (a whopping 9.375 inches longer) and moved the rear seat back aft yet another 76.25 -72.25 or 4 inches? -------- Oscar Zuniga Medford, OR Air Camper NX41CC "Scout" A75 power, 72x36 Culver prop Read this topic online here: http://forums.matronics.com/viewtopic.php?p=465417#465417 ----- No virus found in this message. Checked by AVG - www.avg.com ________________________________ Message 3 _____________________________________ Time: 09:48:34 PM PST US Subject: Pietenpol-List: Re: Long fuselage and Model A From: "taildrags" Jerry: "taildrags R us" ;o) Oscar Zuniga taildrags@hotmail.com -------- Oscar Zuniga Medford, OR Air Camper NX41CC "Scout" A75 power, 72x36 Culver prop Read this topic online here: http://forums.matronics.com/viewtopic.php?p=465445#465445 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message pietenpol-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Pietenpol-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/pietenpol-list Browse Digests http://www.matronics.com/digest/pietenpol-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.