Original Posted By: "DaveM"
Subject: Pietenpol-List: Re: BrazingI have brazed alot of the fittings per the plans and was wondering if the brazingwas strong enough. I used " brass" brazing rod with flux. I am concerned about thebushings for the bell crank. I know there is not that much stress but any input would be appreciated. I tried welding the bushings with 4130 rod and it warp thebushing to where it would not slip over the shaft. My bushings for my control stickassembly are also brass brazed. I did weld the bell crank with 4130 rod and was happy with the results. I would recommend welding the airfoil shape bell crank on.any input would be appreciated.Ron________________________________________________________________________________
Pietenpol-List: Re: Brazing
Pietenpol-List: Pietenpol Center of Gravity Standards (?)
Original Posted By: "SAM & JAN MARINUCCI"
Subject: Pietenpol-List: Pietenpol Center of Gravity Standards (?)>>This is to clarify my previous notes on Pietenpol CG limitations.>>In the old Civil Aeronautics Manual 18 (get one that was issued 6/1/43 or>before - the later ones do not contain the needed information), directions>are given for the mechanic to establish the proper CG limits on aircraft>for which such CG limits were not established by the old Department of>Commerce. CAM 18 of that era showed diagrams and text that stated that in>the case of monoplanes, an acceptable standard is 22% to 34% of the mean>aerodynamic chord (MAC). This is in accord with today's aviation industry>standards. In the case of the Pietenpol, the rectangular wing has>a constant chord of 5 feet, so we can confidently establish the MAC as 60>inches.> 22% of 60 = 13.20 inches aft of wing leading edge is the forward>CG limit> 34% of 60 = 20.40 inches aft of wing leading edge is the rearward>CG limit>>Bernard Pietenpol made the recommendation to never exceed 20" aft of wing>leading edge CG, and this is certainly good advice.>>There are several "authentic" versions of Piet plans, and they vary>somewhat (is that a surprise?) On the "Steel Tube Fuselage Supplement for>Pietenpol AirCamper" dated 3/8/65, a dimensioned 3-view of the "1937 Air>Camper with 1960 Corvair engine" shows the datum as the wing leading>edge. A datum, as defined in the industry, is a fixed (immovable)>identifiable point on the airframe to which other points are>referenced. This would imply that the wing on the Piet is fixed. The>moment the wing is moved fore or aft, the original datum is>destroyed. Most airplanes have a fixed-position wing, making the datum>iimmovable. Often, the front of the firewall is designated as the>datum. It sure does not move.>>On the 3/8/65 Pietenpol (O.C.Hoopman) drawing, the firewall is referenced>as a fixed point. The leading edge of the wing is depicted as 11.25 inches>aft of the firewall, and the leading edge of the wing is>labelled "datum." This implies, of course, that the "datum" is fixed at>that point 11.25 inches aft of the firewall.>>The Pietenpol drawing lists the empty weight of the airplane with a Corvair>engine as "677 lbs." By comparison, the drawing for the Piet with the Ford>engine (the "improved" version) shows the empty weight of the airplane with>the Ford engine as "610 lbs." So here we have the Ford airplane, with the>heavier Model A engine (and even allowing for the extra wood for the>longer fuselage) weighing less than the lighter-engined Corvair>airplane. So much for the accuracy of the Pietenpol plans.>>Better to nail the wing into place and use a clean sheet of paper to run>the proposed CG computations.>>The most obvious and practical way to keep the cabanes and wing struts>straight and to properly balance the Piet is to place the engine (whatever>kind it is) where it should be. If you need help with this, ask any A&P or>IA. Moving the wing is an admission that the builder did not plan>ahead. And keeping the wing in the proper position clears the rear seatentry.>>Anyone deciding to cant the cabane struts to move the wing aft must accept>the fact that the wing itself is a significant portion of the weight of the>Piet, weighing something like 150 pounds. Even the weight of the steel>wing struts moves aft. Moving all that weight aft to correct a rear CG>problem seems hardly the way to correct the original problem.>>The empty weight CG establishment is a rather academic figure, since the>airplane will not be flown in this condition. To a mechanic or>aeronautical engineer, it will be an indicator of things to come when the>aircraft is loaded. More meaningful are the two criteria that must be>met: the most forward CG that will be experienced, and the most rearward>CG that will be experienced.>>The most forward CG on the Piet will be with a lightweight pilot (120>pounds?) in the rear seat. Fuel weight will be a slight factor if the fuel>tank location is forward of the empty CG. With the small amount of fuel in>the Piet and the short moment arm of a fuselage tank, this is almost>negligible concerning the balance of the aircraft. With a wing tank, the>fuel weight is just about on the empty CG.>>The limit everyone is concerned about is the rearward limit. The most>rearward CG will be achieved with a heavy pilot (220 pounds or>more). Since the front seat passenger is very near the empty CG, and the>fuel is at or near the empty CG, these two weights have little effect to>move the actual CG. You can almost make the rule that anything you put>into the rear cockpit of the Piet will determine the operating>CG. Therefore, you should start out with an empty CG that is at or close>to the allowable forward CG limit.>>It is quite possible that there are Pietenpols flying around that are>dangerously exceeding the practical and proven rear CG limits of a standard>high wing airplane, especially with the larger sizes of today's pilots (a>common complaint is that the cockpits are too small).>>Another factor to consider is that many Piets with two people on board are>getting up in weight to over 1100 or even 1200 pounds (some exceed 1250>pounds!). If your FAA operating specifications specify a maximum gross>weight of less than that, you are flying over the placarded weight, and you>should get your FAA operating specs changed to allow your actual operating>weight. Otherwise, you are already in violation and the Friendlies can hit>you.>>Remember the first rule your flight instructor tried to impress on you ->"Don't treat gravity with levity, lest the earth arise and smite>thee!" We're all in it for fun. That's what the Piet is all about.>>Doc Mosher>Oshkosh USA>>________________________________________________________________________________
Subject: Pietenpol-List: Pietenpol Center of Gravity Standards (?)>>This is to clarify my previous notes on Pietenpol CG limitations.>>In the old Civil Aeronautics Manual 18 (get one that was issued 6/1/43 or>before - the later ones do not contain the needed information), directions>are given for the mechanic to establish the proper CG limits on aircraft>for which such CG limits were not established by the old Department of>Commerce. CAM 18 of that era showed diagrams and text that stated that in>the case of monoplanes, an acceptable standard is 22% to 34% of the mean>aerodynamic chord (MAC). This is in accord with today's aviation industry>standards. In the case of the Pietenpol, the rectangular wing has>a constant chord of 5 feet, so we can confidently establish the MAC as 60>inches.> 22% of 60 = 13.20 inches aft of wing leading edge is the forward>CG limit> 34% of 60 = 20.40 inches aft of wing leading edge is the rearward>CG limit>>Bernard Pietenpol made the recommendation to never exceed 20" aft of wing>leading edge CG, and this is certainly good advice.>>There are several "authentic" versions of Piet plans, and they vary>somewhat (is that a surprise?) On the "Steel Tube Fuselage Supplement for>Pietenpol AirCamper" dated 3/8/65, a dimensioned 3-view of the "1937 Air>Camper with 1960 Corvair engine" shows the datum as the wing leading>edge. A datum, as defined in the industry, is a fixed (immovable)>identifiable point on the airframe to which other points are>referenced. This would imply that the wing on the Piet is fixed. The>moment the wing is moved fore or aft, the original datum is>destroyed. Most airplanes have a fixed-position wing, making the datum>iimmovable. Often, the front of the firewall is designated as the>datum. It sure does not move.>>On the 3/8/65 Pietenpol (O.C.Hoopman) drawing, the firewall is referenced>as a fixed point. The leading edge of the wing is depicted as 11.25 inches>aft of the firewall, and the leading edge of the wing is>labelled "datum." This implies, of course, that the "datum" is fixed at>that point 11.25 inches aft of the firewall.>>The Pietenpol drawing lists the empty weight of the airplane with a Corvair>engine as "677 lbs." By comparison, the drawing for the Piet with the Ford>engine (the "improved" version) shows the empty weight of the airplane with>the Ford engine as "610 lbs." So here we have the Ford airplane, with the>heavier Model A engine (and even allowing for the extra wood for the>longer fuselage) weighing less than the lighter-engined Corvair>airplane. So much for the accuracy of the Pietenpol plans.>>Better to nail the wing into place and use a clean sheet of paper to run>the proposed CG computations.>>The most obvious and practical way to keep the cabanes and wing struts>straight and to properly balance the Piet is to place the engine (whatever>kind it is) where it should be. If you need help with this, ask any A&P or>IA. Moving the wing is an admission that the builder did not plan>ahead. And keeping the wing in the proper position clears the rear seatentry.>>Anyone deciding to cant the cabane struts to move the wing aft must accept>the fact that the wing itself is a significant portion of the weight of the>Piet, weighing something like 150 pounds. Even the weight of the steel>wing struts moves aft. Moving all that weight aft to correct a rear CG>problem seems hardly the way to correct the original problem.>>The empty weight CG establishment is a rather academic figure, since the>airplane will not be flown in this condition. To a mechanic or>aeronautical engineer, it will be an indicator of things to come when the>aircraft is loaded. More meaningful are the two criteria that must be>met: the most forward CG that will be experienced, and the most rearward>CG that will be experienced.>>The most forward CG on the Piet will be with a lightweight pilot (120>pounds?) in the rear seat. Fuel weight will be a slight factor if the fuel>tank location is forward of the empty CG. With the small amount of fuel in>the Piet and the short moment arm of a fuselage tank, this is almost>negligible concerning the balance of the aircraft. With a wing tank, the>fuel weight is just about on the empty CG.>>The limit everyone is concerned about is the rearward limit. The most>rearward CG will be achieved with a heavy pilot (220 pounds or>more). Since the front seat passenger is very near the empty CG, and the>fuel is at or near the empty CG, these two weights have little effect to>move the actual CG. You can almost make the rule that anything you put>into the rear cockpit of the Piet will determine the operating>CG. Therefore, you should start out with an empty CG that is at or close>to the allowable forward CG limit.>>It is quite possible that there are Pietenpols flying around that are>dangerously exceeding the practical and proven rear CG limits of a standard>high wing airplane, especially with the larger sizes of today's pilots (a>common complaint is that the cockpits are too small).>>Another factor to consider is that many Piets with two people on board are>getting up in weight to over 1100 or even 1200 pounds (some exceed 1250>pounds!). If your FAA operating specifications specify a maximum gross>weight of less than that, you are flying over the placarded weight, and you>should get your FAA operating specs changed to allow your actual operating>weight. Otherwise, you are already in violation and the Friendlies can hit>you.>>Remember the first rule your flight instructor tried to impress on you ->"Don't treat gravity with levity, lest the earth arise and smite>thee!" We're all in it for fun. That's what the Piet is all about.>>Doc Mosher>Oshkosh USA>>________________________________________________________________________________
Re: Pietenpol-List: Re: Brazing
Original Posted By: "Carl Loar"
If done right, clean metal and proper proceedure, brazing is very strong.That is why it is used for repairs on non-airplane equipment. A good brazedjoint is generally stronger than the individual parent metal peices.Hope this helps.Dave>> I have brazed alot of the fittings per the plans and was wondering if the> brazing> was strong enough. I used " brass" brazing rod with flux. I am concerned> about the> bushings for the bell crank. I know there is not that much stress butany> input> would be appreciated. I tried welding the bushings with 4130 rod and itwarp> the> bushing to where it would not slip over the shaft. My bushings for my> control stick> assembly are also brass brazed.>> I did weld the bell crank with 4130 rod and was happy with the> results. I would recommend welding the airfoil shape bell crank on.>> any input would be appreciated.>> Ron>>________________________________________________________________________________
If done right, clean metal and proper proceedure, brazing is very strong.That is why it is used for repairs on non-airplane equipment. A good brazedjoint is generally stronger than the individual parent metal peices.Hope this helps.Dave>> I have brazed alot of the fittings per the plans and was wondering if the> brazing> was strong enough. I used " brass" brazing rod with flux. I am concerned> about the> bushings for the bell crank. I know there is not that much stress butany> input> would be appreciated. I tried welding the bushings with 4130 rod and itwarp> the> bushing to where it would not slip over the shaft. My bushings for my> control stick> assembly are also brass brazed.>> I did weld the bell crank with 4130 rod and was happy with the> results. I would recommend welding the airfoil shape bell crank on.>> any input would be appreciated.>> Ron>>________________________________________________________________________________
RE: Pietenpol-List: Re: Brazing
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Here's another thought I might throw at the group. Since there is nosidewardforces working on the horns, why wouldn't a good brazing be just as strongto connect the pieces together? With the bushing and the u in place,,, itseemsthat all the horns could be assembled this way... What's everyones thoughton this?Carl-----Original Message-----
Here's another thought I might throw at the group. Since there is nosidewardforces working on the horns, why wouldn't a good brazing be just as strongto connect the pieces together? With the bushing and the u in place,,, itseemsthat all the horns could be assembled this way... What's everyones thoughton this?Carl-----Original Message-----
Pietenpol-List: Re: Brazing
Original Posted By: fishin
Re: Pietenpol-List: BPA newsletter
Original Posted By: Don Mosher
I'm pretty sure I sent dues for 2000 back in '98. Anybody else do the same?Dick G.Ft. Myers, FL________________________________________________________________________________Date: Tue, 04 Jul 2000 10:13:52 -0500
I'm pretty sure I sent dues for 2000 back in '98. Anybody else do the same?Dick G.Ft. Myers, FL________________________________________________________________________________Date: Tue, 04 Jul 2000 10:13:52 -0500
Re: Pietenpol-List: Re: Brazing
Original Posted By: DonanClara(at)aol.com
Subject: Re: Pietenpol-List: Re: BrazingRon, Brazing is done with bronze rods, not brass and bronze is quite strong.The reason brazing is used at all is that it doesn't require as much heatand the possibilities of warpage is reduced. Brazing in bushings or theupright bolt for the rudder bar pivot bolt is plenty strong enough asneither of these are structural in any way. All you're trying to due isto fasten these in position so they won't slip or turn causing a hole toelongate. Use brazing only on non-structural components were warpingcould cause a lot of problems. Also, welding a bolt can cause enoughheat to destroy the temper and strength properties of that bolt. A boltcan crystalize at the weld and cause it to break in time. This is whyBernie said to braze these bolts in place instead of welding. Welding abolt can actually weaken it.John LangstonPipe Creek, TXnle97(at)juno.comBuilding the wing.________________________________________________________________________________
Subject: Re: Pietenpol-List: Re: BrazingRon, Brazing is done with bronze rods, not brass and bronze is quite strong.The reason brazing is used at all is that it doesn't require as much heatand the possibilities of warpage is reduced. Brazing in bushings or theupright bolt for the rudder bar pivot bolt is plenty strong enough asneither of these are structural in any way. All you're trying to due isto fasten these in position so they won't slip or turn causing a hole toelongate. Use brazing only on non-structural components were warpingcould cause a lot of problems. Also, welding a bolt can cause enoughheat to destroy the temper and strength properties of that bolt. A boltcan crystalize at the weld and cause it to break in time. This is whyBernie said to braze these bolts in place instead of welding. Welding abolt can actually weaken it.John LangstonPipe Creek, TXnle97(at)juno.comBuilding the wing.________________________________________________________________________________
Re: Pietenpol-List: Re: Brazing
Original Posted By: nle97(at)juno.com
Subject: Re: Pietenpol-List: Re: BrazingCarl, I welded our horns. It wasn't difficult to do at all and in thisapplication I think it would be best to weld. There is some side load atthe base and this needs to be considered. Warpage can be reduced bywelding short sections at a time.John LangstonPipe Creek, TXnle97(at)juno.com________________________________________________________________________________
Subject: Re: Pietenpol-List: Re: BrazingCarl, I welded our horns. It wasn't difficult to do at all and in thisapplication I think it would be best to weld. There is some side load atthe base and this needs to be considered. Warpage can be reduced bywelding short sections at a time.John LangstonPipe Creek, TXnle97(at)juno.com________________________________________________________________________________
Re: Pietenpol-List: Re: Brazing
Original Posted By: "Michael Conkling"
Subject: Re: Pietenpol-List: Re: BrazingHey guys, Thanks for the advice;-) Its nice to have a little piece of mind. Is BRASS good enough for brazing or should we use COPPER?In addition, I am having a problem with corrosion with the flux. I primered themetal fittings and the flux is flaking off causing the primer to come off.Thanks,Ron________________________________________________________________________________
Subject: Re: Pietenpol-List: Re: BrazingHey guys, Thanks for the advice;-) Its nice to have a little piece of mind. Is BRASS good enough for brazing or should we use COPPER?In addition, I am having a problem with corrosion with the flux. I primered themetal fittings and the flux is flaking off causing the primer to come off.Thanks,Ron________________________________________________________________________________
Re: Pietenpol-List: Re: Brazing
Original Posted By: nle97(at)juno.com
You might try silver solder for the bushings -- you will need about .005"clearance in the joint for it to work well -- the heat required is only inthe 1000-1500 degree range. Use a "too long" piece tubing for the bushing &cut it off after you do the process -- sure beats trying to keep a littlebit of tubing centered while you are heating everything up!
Also, checka crafts shop for the flux -- Jewelers have a neat paste flux for the silversolder.I've used brass fillet brazing on about 1/2 dozen bike frames over the past15 years with good success (my bike frames are still in one piece! -- itdoes take a HOT water soak & a wire brush to clean off the flux (if youdon't, it will lift the primer)Mike ConklingPretty Prairie, KS________________________________________________________________________________
You might try silver solder for the bushings -- you will need about .005"clearance in the joint for it to work well -- the heat required is only inthe 1000-1500 degree range. Use a "too long" piece tubing for the bushing &cut it off after you do the process -- sure beats trying to keep a littlebit of tubing centered while you are heating everything up!
Also, checka crafts shop for the flux -- Jewelers have a neat paste flux for the silversolder.I've used brass fillet brazing on about 1/2 dozen bike frames over the past15 years with good success (my bike frames are still in one piece! -- itdoes take a HOT water soak & a wire brush to clean off the flux (if youdon't, it will lift the primer)Mike ConklingPretty Prairie, KS________________________________________________________________________________Pietenpol-List: Video Inquiries
Original Posted By: "Greg Cardinal"
Subject: Pietenpol-List: Video Inquiries>>Piet Group->>Recently I have received some renewed interest in my 1999 home>video about the building and flying of my Pietenpol Air Camper>and thought I would post this site (below) which has all the info about the>tape.>>http://users.aol.com/bpabpabpa/cuyvideo.html>>>Best Regards,>>Mike Cuy>NX48MC>>________________________________________________________________________________Date: Thu, 06 Jul 2000 10:09:11 -0600
Subject: Pietenpol-List: Video Inquiries>>Piet Group->>Recently I have received some renewed interest in my 1999 home>video about the building and flying of my Pietenpol Air Camper>and thought I would post this site (below) which has all the info about the>tape.>>http://users.aol.com/bpabpabpa/cuyvideo.html>>>Best Regards,>>Mike Cuy>NX48MC>>________________________________________________________________________________Date: Thu, 06 Jul 2000 10:09:11 -0600
Re: Pietenpol-List: BPA newsletter
Original Posted By: "Warren D. Shoun"
Subject: Re: Pietenpol-List: BPA newsletterIn a message dated 07/04/2000 9:23:49 AM Central Daylight Time, dickmarg(at)peganet.com writes:>I paid the full dues through the end of the year...then for some reason Grant 'schedule of dues' printed in the Newsletter indicated additional money was required for the last two months of my already paid up membership. Rather than argue what was a minor point I sent the additional few bucks. Then to add insult to injury I was never sent the last two issues. I'd like to know what caused him to take such a sudden turn. I don't buy the "busy with remodeling" excuse. I'm sure there's a logical reason but he has never, to my knowledge told anyone what it was. I'm not angry, just disappointed in a guy I know to be a fine person. Anyone else with a similar experience ? Don Hicks________________________________________________________________________________Date: Wed, 05 Jul 2000 07:02:33 -0700
Subject: Re: Pietenpol-List: BPA newsletterIn a message dated 07/04/2000 9:23:49 AM Central Daylight Time, dickmarg(at)peganet.com writes:>I paid the full dues through the end of the year...then for some reason Grant 'schedule of dues' printed in the Newsletter indicated additional money was required for the last two months of my already paid up membership. Rather than argue what was a minor point I sent the additional few bucks. Then to add insult to injury I was never sent the last two issues. I'd like to know what caused him to take such a sudden turn. I don't buy the "busy with remodeling" excuse. I'm sure there's a logical reason but he has never, to my knowledge told anyone what it was. I'm not angry, just disappointed in a guy I know to be a fine person. Anyone else with a similar experience ? Don Hicks________________________________________________________________________________Date: Wed, 05 Jul 2000 07:02:33 -0700
Re: Pietenpol-List: BPA newsletter
Original Posted By: fishin
Re: Pietenpol-List: BPA newsletter
Original Posted By: Michael D Cuy
Subject: Re: Pietenpol-List: BPA newsletterI also sent in the extra money and am disappointed. Most of all, I'mjust glad to see it's going again. Grant did a great job and if he wasunable to continue I'm sure he had a very good reason.John LangstonPipe Creek, TXnle97(at)juno.com________________________________________________________________________________Date: Wed, 05 Jul 2000 14:04:30 -0400
Subject: Re: Pietenpol-List: BPA newsletterI also sent in the extra money and am disappointed. Most of all, I'mjust glad to see it's going again. Grant did a great job and if he wasunable to continue I'm sure he had a very good reason.John LangstonPipe Creek, TXnle97(at)juno.com________________________________________________________________________________Date: Wed, 05 Jul 2000 14:04:30 -0400
Re: Pietenpol-List: Pietenpol Center of Gravity Standards (?)
Original Posted By: Don Mosher
Doc, Thanks for clearing alot of things up. This explains alot.There was only one paragraph that I think that you got backwards,,,""Anyone deciding to cant the cabane struts to move the wing aft must acceptthe fact that the wing itself is a significant portion of the weight of thePiet, weighing something like 150 pounds. Even the weight of the steelwing struts moves aft. Moving all that weight aft to correct a rear CGproblem seems hardly the way to correct the original problem.""The way I see it is , what you are doing in theory, is holding the wing atone spot and moving the body and struts forward under it, you are movingweight forward , not aft.Since the whole aircraft is hanging under the wing, ( the wing is the real "flying" " plane") the body has to be "slid" forward to a sweet spot.I'm not to that point yet, and hope that I don't have to modify.walt evans-----------------------------------------------------Click here for Free Video!!http://www.gohip.com/freevideo/-----Original Message-----
Doc, Thanks for clearing alot of things up. This explains alot.There was only one paragraph that I think that you got backwards,,,""Anyone deciding to cant the cabane struts to move the wing aft must acceptthe fact that the wing itself is a significant portion of the weight of thePiet, weighing something like 150 pounds. Even the weight of the steelwing struts moves aft. Moving all that weight aft to correct a rear CGproblem seems hardly the way to correct the original problem.""The way I see it is , what you are doing in theory, is holding the wing atone spot and moving the body and struts forward under it, you are movingweight forward , not aft.Since the whole aircraft is hanging under the wing, ( the wing is the real "flying" " plane") the body has to be "slid" forward to a sweet spot.I'm not to that point yet, and hope that I don't have to modify.walt evans-----------------------------------------------------Click here for Free Video!!http://www.gohip.com/freevideo/-----Original Message-----
Re: Pietenpol-List: Video Inquiries
Original Posted By: Michael D Cuy
To the discussion group, I have a copy of Mikes' video and would highly recommend it toanyone building or even thinking of building a Piet. Although it is anamateur video, there is a wealth of information available. I refer to itfrom time to time just to better understand some details that are unclearto me on the plans. Mike has also added some terrific scenes of his Piet inflight. You won't regret the cost of the video, it's well worth it. Sam-----Original Message-----
To the discussion group, I have a copy of Mikes' video and would highly recommend it toanyone building or even thinking of building a Piet. Although it is anamateur video, there is a wealth of information available. I refer to itfrom time to time just to better understand some details that are unclearto me on the plans. Mike has also added some terrific scenes of his Piet inflight. You won't regret the cost of the video, it's well worth it. Sam-----Original Message-----
Re: Pietenpol-List: Pietenpol Center of Gravity Standards (?)
Original Posted By: Isablcorky(at)aol.com
Walt, your point about moving the wing is the way I thought about it also,your really not moving the wing your moving the fuselage. I helped a friendwith his CG on a Piet some years ago and we had some problems dependablecalculating the effects of a move between wing and fuselage. After lots of thought and chicken scratches on paper I realized that thisis not true. Only if the wing was lighter than air would this be the case.Because the wing has weight it also applies pressure on the loading of thelift surface(itself) and it produces the center of lift. If you look at thecenter of lift of the wing and then figure the moment(CG) of the wing,different parts of the wing have different loads applied.(lbs. per squareinch) When we figure wing loading we calculate the average lb./in sq.. notthe real loading at any given point. This is what CG effects and what thebuilder wants is to have this moment of loading centered over the center oflift. So in effect by moving the struts you effect the CG relative to thecenter of lift but not exactly at the same ratio of effect as you would ifyou placed a weight in the tail or nose at a given distance from the datum.This is what in effect is happening with the 'moving datum' the datum isreally a reference to the center of lift. Which the leading edge of thewing is good for. Because we are moving the relationship of the weight ofthe fuselage to the wing it just makes it much more difficult to calculatethis distance because we need to know the exact moments end to end. Whichis why when I helped a friend do this to his plane we got different resultsthan expected. At the time we attributed it to the scales being non linearbut in fact it was the relationships of the different moments changing. Sowe made small changes until we got the desired results.Or I'm completely nuts. You decide.This will come across as rambling and not make much sense I'm sure.Greg>>Doc,> Thanks for clearing alot of things up. This explains alot.>There was only one paragraph that I think that you got backwards,,,>>""Anyone deciding to cant the cabane struts to move the wing aft mustaccept>the fact that the wing itself is a significant portion of the weight of the>Piet, weighing something like 150 pounds. Even the weight of the steel>wing struts moves aft. Moving all that weight aft to correct a rear CG>problem seems hardly the way to correct the original problem."">>The way I see it is , what you are doing in theory, is holding the wing at>one spot and moving the body and struts forward under it, you are moving>weight forward , not aft.>Since the whole aircraft is hanging under the wing, ( the wing is the real">flying" " plane") the body has to be "slid" forward to a sweet spot.>I'm not to that point yet, and hope that I don't have to modify.>walt evans>________________________________________________________________________________
Walt, your point about moving the wing is the way I thought about it also,your really not moving the wing your moving the fuselage. I helped a friendwith his CG on a Piet some years ago and we had some problems dependablecalculating the effects of a move between wing and fuselage. After lots of thought and chicken scratches on paper I realized that thisis not true. Only if the wing was lighter than air would this be the case.Because the wing has weight it also applies pressure on the loading of thelift surface(itself) and it produces the center of lift. If you look at thecenter of lift of the wing and then figure the moment(CG) of the wing,different parts of the wing have different loads applied.(lbs. per squareinch) When we figure wing loading we calculate the average lb./in sq.. notthe real loading at any given point. This is what CG effects and what thebuilder wants is to have this moment of loading centered over the center oflift. So in effect by moving the struts you effect the CG relative to thecenter of lift but not exactly at the same ratio of effect as you would ifyou placed a weight in the tail or nose at a given distance from the datum.This is what in effect is happening with the 'moving datum' the datum isreally a reference to the center of lift. Which the leading edge of thewing is good for. Because we are moving the relationship of the weight ofthe fuselage to the wing it just makes it much more difficult to calculatethis distance because we need to know the exact moments end to end. Whichis why when I helped a friend do this to his plane we got different resultsthan expected. At the time we attributed it to the scales being non linearbut in fact it was the relationships of the different moments changing. Sowe made small changes until we got the desired results.Or I'm completely nuts. You decide.This will come across as rambling and not make much sense I'm sure.Greg>>Doc,> Thanks for clearing alot of things up. This explains alot.>There was only one paragraph that I think that you got backwards,,,>>""Anyone deciding to cant the cabane struts to move the wing aft mustaccept>the fact that the wing itself is a significant portion of the weight of the>Piet, weighing something like 150 pounds. Even the weight of the steel>wing struts moves aft. Moving all that weight aft to correct a rear CG>problem seems hardly the way to correct the original problem."">>The way I see it is , what you are doing in theory, is holding the wing at>one spot and moving the body and struts forward under it, you are moving>weight forward , not aft.>Since the whole aircraft is hanging under the wing, ( the wing is the real">flying" " plane") the body has to be "slid" forward to a sweet spot.>I'm not to that point yet, and hope that I don't have to modify.>walt evans>________________________________________________________________________________
RE: Pietenpol-List: Brazing
Original Posted By: owner-pietenpol-list-server(at)matronics.com
I thought we pounded through this a while back...if it is 4130 no brazingallowed....chris bobka-----Original Message-----
I thought we pounded through this a while back...if it is 4130 no brazingallowed....chris bobka-----Original Message-----
Re: Pietenpol-List: Brazing
Original Posted By: "D.Dale Johnson"
Subject: Re: Pietenpol-List: Brazing
Subject: Re: Pietenpol-List: Brazing
Re: Pietenpol-List: Brazing
Original Posted By: "Christian Bobka"
Larry,Yeah, it seems that on the old steel tubing it was great. But if you'reusing chromoly, the braze isn't compatible with either the chromium orthe molibdenum, I forget which.Seems to be common knowledge out there. Thats one of the first things mymentor told me while looking over my new plans.one of the things that pushed me to learn Oxy-Acet. welding, and I'm glad Idid.A few on this list are really good on the metalurgy , and posted some reallygood notes on this. Check the archives.waltNX140DL----- Original Message -----
Larry,Yeah, it seems that on the old steel tubing it was great. But if you'reusing chromoly, the braze isn't compatible with either the chromium orthe molibdenum, I forget which.Seems to be common knowledge out there. Thats one of the first things mymentor told me while looking over my new plans.one of the things that pushed me to learn Oxy-Acet. welding, and I'm glad Idid.A few on this list are really good on the metalurgy , and posted some reallygood notes on this. Check the archives.waltNX140DL----- Original Message -----
Re: Pietenpol-List: Brazing
Original Posted By: "John Dilatush"
Subject: Re: Pietenpol-List: BrazingIn a message dated 5/22/02 9:58:55 AM Pacific Daylight Time, llneal2(at)earthlink.net writes:> Well, I didn't have any trouble remembering how to braze, in fact this > is fun!> I put together my control tube a couple of weeks back and last night > made up the elevator bell crank. It was easier than it looks, I wish > I'd started on this end of things sooner.> One question though, my brazing rod leaves a glass-like slag that's a > bear to get off afterwards. Does anyone have any tips on how to remove it?> > Larry> > Larry,Boiling water will remove the flux. Doug Bryant ________________________________________________________________________________
Subject: Re: Pietenpol-List: BrazingIn a message dated 5/22/02 9:58:55 AM Pacific Daylight Time, llneal2(at)earthlink.net writes:> Well, I didn't have any trouble remembering how to braze, in fact this > is fun!> I put together my control tube a couple of weeks back and last night > made up the elevator bell crank. It was easier than it looks, I wish > I'd started on this end of things sooner.> One question though, my brazing rod leaves a glass-like slag that's a > bear to get off afterwards. Does anyone have any tips on how to remove it?> > Larry> > Larry,Boiling water will remove the flux. Doug Bryant ________________________________________________________________________________
Re: Pietenpol-List: Brazing
Original Posted By: "Larry Neal"
Steve Wittman I believe Brazed the tail feathers on his tailwind. I could bewrong so I am sending this message on to the tailwind group.Cy Galley, TC - Chair, Emergency Aircraft Repair, Oshkosh----- Original Message -----
Steve Wittman I believe Brazed the tail feathers on his tailwind. I could bewrong so I am sending this message on to the tailwind group.Cy Galley, TC - Chair, Emergency Aircraft Repair, Oshkosh----- Original Message -----
> Pietenpol-List: Brazing
Original Posted By: Mpj01(at)aol.com
Re: Pietenpol-List: rudder pedals
Original Posted By: Steven Schaefer
Re: Pietenpol-List: Brazing
Original Posted By: clif
Subject: Re: Pietenpol-List: BrazingIn a message dated 5/23/02 8:09:29 AM Central Daylight Time, cgalley(at)qcbc.org writes:>This is correct. I got a case of builders withdrawl, and have started building a W10. The Tailwind plans call for braizing 1 1/8" X .025" stainless steel trailing edges to the 4130 tubing on the tail, as well as the ailerons and flaps. The plans also specifically call out braizing the channel, in the tail section, to the tubing. All tubing in the plans call out 4130 steel. Everything else is welded, preferably oxy / accy weld.Chuck GantzerNX770CGStill waiting for my next sojourn in the sky.________________________________________________________________________________Date: Fri, 24 May 2002 01:34:13 -0700
Subject: Re: Pietenpol-List: BrazingIn a message dated 5/23/02 8:09:29 AM Central Daylight Time, cgalley(at)qcbc.org writes:>This is correct. I got a case of builders withdrawl, and have started building a W10. The Tailwind plans call for braizing 1 1/8" X .025" stainless steel trailing edges to the 4130 tubing on the tail, as well as the ailerons and flaps. The plans also specifically call out braizing the channel, in the tail section, to the tubing. All tubing in the plans call out 4130 steel. Everything else is welded, preferably oxy / accy weld.Chuck GantzerNX770CGStill waiting for my next sojourn in the sky.________________________________________________________________________________Date: Fri, 24 May 2002 01:34:13 -0700