Original Posted By: "Chris Rusch"
No flames ... just a question.The step button seems like a good, simple method to lock the tube in position.I'm just curious as to how you will be able to push the button to collapse thestep when you're sitting in the pilot's seat. Maybe you have exceptionally longarms, or is there a secret?BCRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: W/B QUESTION
Pietenpol-List: W/B QUESTION
Original Posted By: KM Heide CPO/FAAOP
When calculating weight and balance, where do you locate the arm? in the centerof the cg range? From the leading edge?and you use negative numbers for distance in front of the datum correct?ThanksRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 20 Sep 2011 09:59:59 -0700 (PDT)
When calculating weight and balance, where do you locate the arm? in the centerof the cg range? From the leading edge?and you use negative numbers for distance in front of the datum correct?ThanksRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 20 Sep 2011 09:59:59 -0700 (PDT)
Pietenpol-List: Re: W/B QUESTION
Original Posted By: "TOM STINEMETZE"
Now here's a serious answer to what I think is your question.1. You can locate the datum (reference point) anywhere you want. For example,most big planes use an imaginary point in front of the aircraft so that all armsare positive. Many small aircraft use something like the prop flange, firewall,wing leading edge, whatever, as long as it can give you a single verticalreference plane perpendicular to the long axis of the aircraft. Most Pietenpolbuilders use the firewall since it's a vertical plane and easy to measurefrom.2. The "arm" is simply a distance from the datum, aft is positive and forwardis negative. In the case of initial weight and balance calculations, you simplelevel the aircraft and measure the distance from the datum/firewall to eachof the 3 wheels. Weight x Arm = Moment. Add the weights, add the moments toget a total weight and moment. Then divide moment by weight and that gives youanother arm. That arm is the distance of the cg from the datum. Then measurefrom the datum to the wing and if it falls within the acceptable range, you'realmost done. You now have the empty weight and cg and all other calculationsstart from that. 3. To add people, fuel, baggage or equipment, just do the weight x arm = momentcalculations for each item and then add the empty weight and cg info. Justremember that weights and moments add but the overall arm is a calculated number.To figure out whether you are withing cg limits in a flyable aircraft, takejust the aft cg items (on a Piet, that's typically just the pilot) and calculatethe maximum aft cg. If it is forward of the max aft published, then youare good. Do the same with forward cg (typically a "light" pilot as min crew)and add fuel, max pax weight and do the W x A = M calculations. Again, ifthe calculated arm falls withing the cg range, go forth and sin no more. If not,move the wing until it does.This is a little like telling you how to build a watch when you just wanted toknow the time but it should answer your question. DaveRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 20 Sep 2011 13:04:21 -0500
Now here's a serious answer to what I think is your question.1. You can locate the datum (reference point) anywhere you want. For example,most big planes use an imaginary point in front of the aircraft so that all armsare positive. Many small aircraft use something like the prop flange, firewall,wing leading edge, whatever, as long as it can give you a single verticalreference plane perpendicular to the long axis of the aircraft. Most Pietenpolbuilders use the firewall since it's a vertical plane and easy to measurefrom.2. The "arm" is simply a distance from the datum, aft is positive and forwardis negative. In the case of initial weight and balance calculations, you simplelevel the aircraft and measure the distance from the datum/firewall to eachof the 3 wheels. Weight x Arm = Moment. Add the weights, add the moments toget a total weight and moment. Then divide moment by weight and that gives youanother arm. That arm is the distance of the cg from the datum. Then measurefrom the datum to the wing and if it falls within the acceptable range, you'realmost done. You now have the empty weight and cg and all other calculationsstart from that. 3. To add people, fuel, baggage or equipment, just do the weight x arm = momentcalculations for each item and then add the empty weight and cg info. Justremember that weights and moments add but the overall arm is a calculated number.To figure out whether you are withing cg limits in a flyable aircraft, takejust the aft cg items (on a Piet, that's typically just the pilot) and calculatethe maximum aft cg. If it is forward of the max aft published, then youare good. Do the same with forward cg (typically a "light" pilot as min crew)and add fuel, max pax weight and do the W x A = M calculations. Again, ifthe calculated arm falls withing the cg range, go forth and sin no more. If not,move the wing until it does.This is a little like telling you how to build a watch when you just wanted toknow the time but it should answer your question. DaveRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 20 Sep 2011 13:04:21 -0500
RE: Pietenpol-List: Re: W/B QUESTION
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Good post, Dave.Jack PhillipsNX899JPSmith Mountain Lake, Virginia-----Original Message-----
Good post, Dave.Jack PhillipsNX899JPSmith Mountain Lake, Virginia-----Original Message-----
Pietenpol-List: Re: W/B QUESTION
Original Posted By: "TOM STINEMETZE"
Pietenpol-List: Re: W/B QUESTION
Original Posted By: Jim Markle
On "balance" I imagine your "arm" is tired after typing that fine explanation.....When you could have just explained that "if you give me the money for a 120 it'lltake a 120........"--------Jake Schultz - curator,Newport Way Air Museum (OK, it's just my home)Read this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 20 Sep 2011 15:41:12 -0400 (GMT-04:00)
On "balance" I imagine your "arm" is tired after typing that fine explanation.....When you could have just explained that "if you give me the money for a 120 it'lltake a 120........"--------Jake Schultz - curator,Newport Way Air Museum (OK, it's just my home)Read this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 20 Sep 2011 15:41:12 -0400 (GMT-04:00)
Pietenpol-List: Re: W/B QUESTION
Original Posted By: Jim Markle
Pietenpol-List: Re: Retractable sliding step
Original Posted By: "rvanengen"
dgaldrich wrote:> Now here's a serious answer to what I think is your question.> > 1. You can locate the datum (reference point) anywhere you want. For example,most big planes use an imaginary point in front of the aircraft so that allarms are positive. Many small aircraft use something like the prop flange, firewall,wing leading edge, whatever, as long as it can give you a single verticalreference plane perpendicular to the long axis of the aircraft. Most Pietenpolbuilders use the firewall since it's a vertical plane and easy to measurefrom.> > 2. The "arm" is simply a distance from the datum, aft is positive and forwardis negative. In the case of initial weight and balance calculations, you simplelevel the aircraft and measure the distance from the datum/firewall to eachof the 3 wheels. Weight x Arm = Moment. Add the weights, add the momentsto get a total weight and moment. Then divide moment by weight and that givesyou another arm. That arm is the distance of the cg from the datum. Then measurefrom the datum to the wing and if it falls within the acceptable range,you're almost done. You now have the empty weight and cg and all other calculationsstart from that. > > 3. To add people, fuel, baggage or equipment, just do the weight x arm = momentcalculations for each item and then add the empty weight and cg info. Justremember that weights and moments add but the overall arm is a calculated number.To figure out whether you are withing cg limits in a flyable aircraft,take just the aft cg items (on a Piet, that's typically just the pilot) and calculatethe maximum aft cg. If it is forward of the max aft published, then youare good. Do the same with forward cg (typically a "light" pilot as min crew)and add fuel, max pax weight and do the W x A = M calculations. Again, ifthe calculated arm falls withing the cg range, go forth and sin no more. Ifnot, move the wing until it does.> > This is a little like telling you how to build a watch when you just wanted toknow the time but it should answer your question. > > DaveDave thank you, that helps clear things up.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Retractable sliding step
dgaldrich wrote:> Now here's a serious answer to what I think is your question.> > 1. You can locate the datum (reference point) anywhere you want. For example,most big planes use an imaginary point in front of the aircraft so that allarms are positive. Many small aircraft use something like the prop flange, firewall,wing leading edge, whatever, as long as it can give you a single verticalreference plane perpendicular to the long axis of the aircraft. Most Pietenpolbuilders use the firewall since it's a vertical plane and easy to measurefrom.> > 2. The "arm" is simply a distance from the datum, aft is positive and forwardis negative. In the case of initial weight and balance calculations, you simplelevel the aircraft and measure the distance from the datum/firewall to eachof the 3 wheels. Weight x Arm = Moment. Add the weights, add the momentsto get a total weight and moment. Then divide moment by weight and that givesyou another arm. That arm is the distance of the cg from the datum. Then measurefrom the datum to the wing and if it falls within the acceptable range,you're almost done. You now have the empty weight and cg and all other calculationsstart from that. > > 3. To add people, fuel, baggage or equipment, just do the weight x arm = momentcalculations for each item and then add the empty weight and cg info. Justremember that weights and moments add but the overall arm is a calculated number.To figure out whether you are withing cg limits in a flyable aircraft,take just the aft cg items (on a Piet, that's typically just the pilot) and calculatethe maximum aft cg. If it is forward of the max aft published, then youare good. Do the same with forward cg (typically a "light" pilot as min crew)and add fuel, max pax weight and do the W x A = M calculations. Again, ifthe calculated arm falls withing the cg range, go forth and sin no more. Ifnot, move the wing until it does.> > This is a little like telling you how to build a watch when you just wanted toknow the time but it should answer your question. > > DaveDave thank you, that helps clear things up.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Retractable sliding step
Pietenpol-List: Re: W/B QUESTION
Original Posted By: Doug Dever
The one footnote I should have included is that when you weight the airplane, younormally include engine oil and unusable fuel when you do the empty weightcalculations.The one mantra of weight and balance is "Weights and moments add; arms do not".And for Bill Church, fingers also add.DaveRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 20 Sep 2011 18:10:49 -0700 (PDT)
The one footnote I should have included is that when you weight the airplane, younormally include engine oil and unusable fuel when you do the empty weightcalculations.The one mantra of weight and balance is "Weights and moments add; arms do not".And for Bill Church, fingers also add.DaveRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 20 Sep 2011 18:10:49 -0700 (PDT)
Re: Pietenpol-List: Re: W/B QUESTION
Original Posted By: "Jack"
So! Just for Billy Canuck, How do you countto 1023 on ten fingers?ClifThe one mantra of weight and balance is "Weights and moments add; arms do not". And for Bill Church, fingers also add.>> Dave________________________________________________________________________________
So! Just for Billy Canuck, How do you countto 1023 on ten fingers?ClifThe one mantra of weight and balance is "Weights and moments add; arms do not". And for Bill Church, fingers also add.>> Dave________________________________________________________________________________
Re: Pietenpol-List: W/B QUESTION
Original Posted By: Ryan Mueller
Chris; I'll pass along a few comments from when I have done the W&B onmy airplane (once after the rebuild, the second time after the enginechange). I go with what others have said... include oil and unusablefuel in the basic empty weight. However, those are easy enough toadd and deduct. And use a W&B spreadsheet... there are several ofthem available from the archives or just ask on this list and you'llget one or more. Makes doing "what-ifs" much quicker and easier.So I used the wing leading edge as the datum since the usual CG limitsare stated as a range that is a percentage of the wing chord (60" chord inthe case of our wings). I started out by setting the fuselage leveland stable, wheels blocked or chocked, tailwheel elevated on a steadystand. I placed a level on the cockpit longeron (actually on the undersideof the longeron), clamped in place, and leveled the fuselage. That's veryimportant.I took a line and plumb bob and dropped them over the leading edge ofthe wing right where the centersection and wing panel join, but reallyanyplace convenient where the plumb bob can drop down to just at thefloor. Let it stop moving and mark that as the reference againstwhich everything else is measured.I laid a line of tape down from the center of the contact patch of onetire across to the other tire as the line that represents the mains.I dropped a plumb bob from the center of the tailwheel down to the floorand marked that spot, and also dropped a plumb bob from the center ofthe firewall down to the floor and marked that spot, then connected thosewith a line of tape representing the long axis of the airplane. youcould also do it from the center of the prop, if you don't have any offsetin your engine thrust line. Now you have everything you need to measurethings from, and you should write down all the essential dimensionsbecause you'll need them when you go to weigh the airplane. Tailwheelfrom datum, mains from datum, fuel tank from datum, passenger and pilotfrom datum (although you can determine the latter three by weighinglater).While the airplane is in the level position you can also measure theangle of your cabanes and other stuff. You can measure the approximatewheelbase, but that will change after you install the wings and thesprings or bungees are compressed. You don't need that value forW&B though.Knowing where your main gear axle centerline falls relative to the datumis very useful in light of the recent articles that William Wynne wrotein the newsletter (thanks, Ryan and others, too). This is a good timeto make adjustments if they are needed, but you'll know more as youbegin to add the wings and accessories and you determine where yourfinal CG is. Oscar ZunigaAir Camper NX41CC "Scout"Flying Squirrel N2069Z "Rocket"Medford, ORwebsite at http://www.flysquirrel.net ________________________________________________________________________________Date: Wed, 21 Sep 2011 22:07:16 -0500Subject: Re: Pietenpol-List: W/B QUESTION
Chris; I'll pass along a few comments from when I have done the W&B onmy airplane (once after the rebuild, the second time after the enginechange). I go with what others have said... include oil and unusablefuel in the basic empty weight. However, those are easy enough toadd and deduct. And use a W&B spreadsheet... there are several ofthem available from the archives or just ask on this list and you'llget one or more. Makes doing "what-ifs" much quicker and easier.So I used the wing leading edge as the datum since the usual CG limitsare stated as a range that is a percentage of the wing chord (60" chord inthe case of our wings). I started out by setting the fuselage leveland stable, wheels blocked or chocked, tailwheel elevated on a steadystand. I placed a level on the cockpit longeron (actually on the undersideof the longeron), clamped in place, and leveled the fuselage. That's veryimportant.I took a line and plumb bob and dropped them over the leading edge ofthe wing right where the centersection and wing panel join, but reallyanyplace convenient where the plumb bob can drop down to just at thefloor. Let it stop moving and mark that as the reference againstwhich everything else is measured.I laid a line of tape down from the center of the contact patch of onetire across to the other tire as the line that represents the mains.I dropped a plumb bob from the center of the tailwheel down to the floorand marked that spot, and also dropped a plumb bob from the center ofthe firewall down to the floor and marked that spot, then connected thosewith a line of tape representing the long axis of the airplane. youcould also do it from the center of the prop, if you don't have any offsetin your engine thrust line. Now you have everything you need to measurethings from, and you should write down all the essential dimensionsbecause you'll need them when you go to weigh the airplane. Tailwheelfrom datum, mains from datum, fuel tank from datum, passenger and pilotfrom datum (although you can determine the latter three by weighinglater).While the airplane is in the level position you can also measure theangle of your cabanes and other stuff. You can measure the approximatewheelbase, but that will change after you install the wings and thesprings or bungees are compressed. You don't need that value forW&B though.Knowing where your main gear axle centerline falls relative to the datumis very useful in light of the recent articles that William Wynne wrotein the newsletter (thanks, Ryan and others, too). This is a good timeto make adjustments if they are needed, but you'll know more as youbegin to add the wings and accessories and you determine where yourfinal CG is. Oscar ZunigaAir Camper NX41CC "Scout"Flying Squirrel N2069Z "Rocket"Medford, ORwebsite at http://www.flysquirrel.net ________________________________________________________________________________Date: Wed, 21 Sep 2011 22:07:16 -0500Subject: Re: Pietenpol-List: W/B QUESTION
Pietenpol-List: Re: W/B QUESTION
Original Posted By: "dwilson"
HI John,The engine is actually out of a Allis Chalmers forklift..that is why it makes powerat such a low rpm. The bottom end is built like a tank, forged nitrited crankfrom the factory and a great oiling system. The head is an aluminum crossflow hemi type. The OHC is chain driven.They were also used in Mitsubishi and Clark forklifts. I used an Electromotive distributorless ignition, it has a magnetic pick up andcoil packs, so far it works awesome.The engine is a 4G54 non balanced engine..they were used in cars too, but mostof them had balance shafts with crappy heads and oil pumps..........so my recommendationwould be the forklift variety. The cams are also different.ChrisRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: W/B QUESTION
HI John,The engine is actually out of a Allis Chalmers forklift..that is why it makes powerat such a low rpm. The bottom end is built like a tank, forged nitrited crankfrom the factory and a great oiling system. The head is an aluminum crossflow hemi type. The OHC is chain driven.They were also used in Mitsubishi and Clark forklifts. I used an Electromotive distributorless ignition, it has a magnetic pick up andcoil packs, so far it works awesome.The engine is a 4G54 non balanced engine..they were used in cars too, but mostof them had balance shafts with crappy heads and oil pumps..........so my recommendationwould be the forklift variety. The cams are also different.ChrisRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: W/B QUESTION
Original Posted By: Oscar Zuniga
Here's how Bernie did it.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ttachments: http://forums.matronics.com//files/piet ... __________
Here's how Bernie did it.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ttachments: http://forums.matronics.com//files/piet ... __________
> RE: Pietenpol-List: Retractable sliding step
Original Posted By:>
> > > > > > > > > > > > > > > > > > > Ken, looks> good, where did you get the button> clips? > > Thanks,> > > Jack> > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Ken, looks> good, where did you get the button> clips? > > Thanks,> > > Jack> > > > > > > > > > > > >
> Pietenpol-List: Re: Retractable sliding step
Original Posted By: JOSEPH SWITHIN
> --> Pietenpol-List message posted> by: "Bill Church" > > No flames ... just a question.> The step button seems like a good, simple method to lock> the tube in position. I'm just curious as to how you will be> able to push the button to collapse the step when you're> sitting in the pilot's seat. Maybe you have exceptionally> long arms, or is there a secret?> > BC> > > > > Read this topic online here:> > http://forums.matronics.com/viewtopic.p ... 759#352759> > > > > > > > Email Forum -> FAQ,> - MATRONICS WEB FORUMS -> List Contribution Web Site -> -Matt> Dralle, List Admin.> > > > ________________________________________________________________________________Date: Tue, 20 Sep 2011 10:44:28 -0700 (PDT)
> --> Pietenpol-List message posted> by: "Bill Church" > > No flames ... just a question.> The step button seems like a good, simple method to lock> the tube in position. I'm just curious as to how you will be> able to push the button to collapse the step when you're> sitting in the pilot's seat. Maybe you have exceptionally> long arms, or is there a secret?> > BC> > > > > Read this topic online here:> > http://forums.matronics.com/viewtopic.p ... 759#352759> > > > > > > > Email Forum -> FAQ,> - MATRONICS WEB FORUMS -> List Contribution Web Site -> -Matt> Dralle, List Admin.> > > > ________________________________________________________________________________Date: Tue, 20 Sep 2011 10:44:28 -0700 (PDT)