Pietenpol-List Digest Archive

Sat 03/29/03


Total Messages Posted: 9



Today's Message Index:
----------------------
 
     1. 02:56 PM - cabane bolt edge clearance (DJ Vegh)
     2. 03:49 PM - Re: cabane bolt edge clearance (John Carmen)
     3. 05:17 PM - Re: cabane bolt edge clearance (Jack Phillips)
     4. 05:35 PM - Re: cabane bolt edge clearance (Kevin Holcomb)
     5. 05:55 PM - Re: cabane bolt edge clearance (John Carmen)
     6. 06:05 PM - Re: SNF (Gene Rambo)
     7. 06:52 PM - Re: cabane bolt edge clearance (clif)
     8. 07:19 PM - Re: SNF (Jack Phillips)
     9. 07:45 PM - Re: SNF (Ted Brousseau)
 
 
 


Message 1


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    Time: 02:56:00 PM PST US
    From: "DJ Vegh" <aircamper@imagedv.com>
    Subject: cabane bolt edge clearance
    --> Pietenpol-List message posted by: "DJ Vegh" <aircamper@imagedv.com> Keep in mind I am building a GN-1 which has a different method of attaching cabanes to wing center section. I'm having a bit of dilemma. I am using Skytec extruded aluminum streamlined struts for cabanes and lift struts. The struts are hollow cored with flats on the insides to allow a 3-6" piece of 3/4" x 3/4" solid aluminum bar to be slipped in which allows you to terminate the ends by having an inch or so of that bar stick out past the strut. You then bolt the strut to the structure with that piece of bar. Problem is, a 3/4" x3/4" solid aluminum bar only allows me an AN3 bolt because of edge clearance issues. As I recall, the rule is 2D from center to edge (where D is diameter of hole). 2D of an AN3 is 3/8" which allows proper clearance, but I feel I really need an AN4 to attach the tops of the cabanes to the wing spar center section fittings. Here's what I can do: 1. Drill out to 1/4" for an AN4 anyway and disregard the edge clearance recommendations. 2. Taper a 1x1" bar to 3/4 x 3/4 and use an AN4 in the 1" portion (this method may look wierd) 3. Use AN3's to bolt the tops of the cabanes to the wing spar fittings. (will 4 AN3's do the job of holding the wing center section in place?) 4. use 3/4" x 3/4" .080 wall 4130 steel instead of solid aluminum bar and drill for AN4's 5. use 3/4 x 3/4" solid steel bar instead of aluminum and drill for AN4's (a heavy solution) No. 4 & 5 makes me wonder if edge clearance guidelines are different for steel than aluminum...... are they?? I need advice! DJ Vegh www.imagedv.com/aircamper Mesa, AZ N74DV This email has been scanned for known viruses and made safe for viewing by Half Price Hosting, a leading email and web hosting provider. For more information on an anti-virus email solution, visit <http://www.halfpricehosting.com/av.asp>.


    Message 2


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    Time: 03:49:23 PM PST US
    From: "John Carmen" <jlcarmen@bellsouth.net>
    Subject: Re: cabane bolt edge clearance
    --> Pietenpol-List message posted by: "John Carmen" <jlcarmen@bellsouth.net> DJ I would make one hole 1/4 and the other 3/16. larger one inboard, and make both bolts NAS1103. These bolts are under shear thus 1/4 and 3/16 NAS should be plenty strong enough. A NAS bolt will allow you to tighten more thus allow more binding force to the aluminum bar and strut. make the hole close tolerance .247 and .186( use a reamer to final the hole). and use chamfered washers on the heads. And if you can get a piece of 7075-T6 aluminum bar, it will be stronger than 2024-T6. How's this? John ----- Original Message ----- From: "DJ Vegh" <aircamper@imagedv.com> Subject: Pietenpol-List: cabane bolt edge clearance > --> Pietenpol-List message posted by: "DJ Vegh" <aircamper@imagedv.com> > > Keep in mind I am building a GN-1 which has a different method of attaching > cabanes to wing center section. > > I'm having a bit of dilemma. I am using Skytec extruded aluminum > streamlined struts for cabanes and lift struts. The struts are hollow cored > with flats on the insides to allow a 3-6" piece of 3/4" x 3/4" solid > aluminum bar to be slipped in which allows you to terminate the ends by > having an inch or so of that bar stick out past the strut. You then bolt the > strut to the structure with that piece of bar. > > Problem is, a 3/4" x3/4" solid aluminum bar only allows me an AN3 bolt > because of edge clearance issues. As I recall, the rule is 2D from center > to edge (where D is diameter of hole). 2D of an AN3 is 3/8" which allows > proper clearance, but I feel I really need an AN4 to attach the tops of the > cabanes to the wing spar center section fittings. > > Here's what I can do: > > 1. Drill out to 1/4" for an AN4 anyway and disregard the edge clearance > recommendations. > > 2. Taper a 1x1" bar to 3/4 x 3/4 and use an AN4 in the 1" portion (this > method may look wierd) > > 3. Use AN3's to bolt the tops of the cabanes to the wing spar fittings. > (will 4 AN3's do the job of holding the wing center section in place?) > > 4. use 3/4" x 3/4" .080 wall 4130 steel instead of solid aluminum bar and > drill for AN4's > > 5. use 3/4 x 3/4" solid steel bar instead of aluminum and drill for AN4's (a > heavy solution) > > > No. 4 & 5 makes me wonder if edge clearance guidelines are different for > steel than aluminum...... are they?? > > I need advice! > > DJ Vegh > www.imagedv.com/aircamper > Mesa, AZ > N74DV > > > This email has been scanned for known viruses and made safe for viewing by Half Price Hosting, a leading email and web hosting provider. For more information on an anti-virus email solution, visit <http://www.halfpricehosting.com/av.asp>. > >


    Message 3


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    Time: 05:17:32 PM PST US
    From: "Jack Phillips" <pietflyr@bellsouth.net>
    Subject: cabane bolt edge clearance
    --> Pietenpol-List message posted by: "Jack Phillips" <pietflyr@bellsouth.net> DJ, I would go ahead and use the AN4 bolt. The 2D edge distance is primarily a consideration for riveted joints, where the spreading rivet can cause cracking of the base metal if too close to the edge. I pulled out my old rivet installation standard from my days in the aerospace business and found that for 1/4" rivets the standard edge distance was .50", but the "Engineering Minimum" was .40" for material .064" thick and thicker, and the "Inspection Minimum" was .37" for those conditions. The Engnieering Minimum was the minimum value that could be specified on the drawing without having a special signoff by the stress analysis group, but the inspection minimum allowed the shop to screw up a little bit and go a little below the minimum engineering standard. Bear in mind that this was for supersonic jet fighters. I think it will be OK for a Pietengrega. As John Carmen pointed out, these bolts are loaded in shear (double shear, actually) and I would be concerned about the aluminum piece shearing with a 3/16" hole in it. Since the aluminum is considerably softer than the steel bolt, the bolt would likely wallow a hole in the aluminum and allow you wing to clunk up and down every time you hit a little turbulence. An AN4 bolt offers 33% more shear area than an AN3. Good Luck, Jack Keep in mind I am building a GN-1 which has a different method of attaching cabanes to wing center section. I'm having a bit of dilemma. I am using Skytec extruded aluminum streamlined struts for cabanes and lift struts. The struts are hollow cored with flats on the insides to allow a 3-6" piece of 3/4" x 3/4" solid aluminum bar to be slipped in which allows you to terminate the ends by having an inch or so of that bar stick out past the strut. You then bolt the strut to the structure with that piece of bar. Problem is, a 3/4" x3/4" solid aluminum bar only allows me an AN3 bolt because of edge clearance issues. As I recall, the rule is 2D from center to edge (where D is diameter of hole). 2D of an AN3 is 3/8" which allows proper clearance, but I feel I really need an AN4 to attach the tops of the cabanes to the wing spar center section fittings. Here's what I can do: 1. Drill out to 1/4" for an AN4 anyway and disregard the edge clearance recommendations. 2. Taper a 1x1" bar to 3/4 x 3/4 and use an AN4 in the 1" portion (this method may look wierd) 3. Use AN3's to bolt the tops of the cabanes to the wing spar fittings. (will 4 AN3's do the job of holding the wing center section in place?) 4. use 3/4" x 3/4" .080 wall 4130 steel instead of solid aluminum bar and drill for AN4's 5. use 3/4 x 3/4" solid steel bar instead of aluminum and drill for AN4's (a heavy solution) No. 4 & 5 makes me wonder if edge clearance guidelines are different for steel than aluminum...... are they?? I need advice! DJ Vegh www.imagedv.com/aircamper Mesa, AZ N74DV


    Message 4


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    Time: 05:35:03 PM PST US
    From: "Kevin Holcomb" <ksholcomb@mindspring.com>
    Subject: Re: cabane bolt edge clearance
    --> Pietenpol-List message posted by: "Kevin Holcomb" <ksholcomb@mindspring.com> Here is a bit of background that may help you. The Aerospace industry requires substantiation of structures, and to show something is strong enough you need to know it's material properties. Years ago the US government did the industry a huge favor by developing a handbook on materail properties for metals (MIL-HDBK-5.) This handbook gave bearing data for 1.5D and 2D edge distance. It is of course conservative to use the 2D values if you have a larger ED. However, if you want to use something less than 1.5D in a design you have to come up with your own material properties. As it is much more accepted, cheaper and quicker to use the published ones the industry demands at least 1.5D. At less than 1.5D there will of course be some strength, but there is not an accepted chart documenting what that strength must be. Thus virtually anything designed will require at least 1.5D. This is where the 1.5D rule came from. It should also be noted that this practice will keep you out of trouble as the material properties drop off rapidly as you get closer than 1.5D. For initial design, most manufacturers start with at least 2D. This is because you can upsize the bolts at least once and still have at least your 1.5D provided of course the hole was drilled where it was supposed to be. In fact some manufacturers use 2D+.06 as an initial ED requirement as that allows for the bolts to be upsized if the hole is miss-drilled, or if it is later determined that the bolts need to be stronger. The +.060 is two +/-.03 tolerances (one incase the edge is cut short and one in case the hole is drilled short). These rules exist to reduce scrap rates. The simple facts are that in the manufacturing industry to be profitable you cannot avoid to throw away much of what you build. To cut scrap you design things such that there is margin for imperfections in the manufacturing process (it is not reasonable to expect that every hole will be located perfectly and drilled perfectly.) If you decide to use 1.5D, you need to first do the calculations and carefully consider your design to make sure that it will be adequate. Also, when fabricating your parts be very careful as this is 1.5D as drilled (measured from the center of the hole to the edge of the part). Which means you must not oversize the hole and it must be located where you need it to be. My advice is use at least 1.5D+.032 and be very careful. My advice, when possible build per print. At the very least the design on the print has been tried before which often means more to me than a shelf full of engineering models. Kevin ----- Original Message ----- From: "DJ Vegh" <aircamper@imagedv.com> Subject: Pietenpol-List: cabane bolt edge clearance > --> Pietenpol-List message posted by: "DJ Vegh" <aircamper@imagedv.com> > > Keep in mind I am building a GN-1 which has a different method of attaching > cabanes to wing center section. > > I'm having a bit of dilemma. I am using Skytec extruded aluminum > streamlined struts for cabanes and lift struts. The struts are hollow cored > with flats on the insides to allow a 3-6" piece of 3/4" x 3/4" solid > aluminum bar to be slipped in which allows you to terminate the ends by > having an inch or so of that bar stick out past the strut. You then bolt the > strut to the structure with that piece of bar. > > Problem is, a 3/4" x3/4" solid aluminum bar only allows me an AN3 bolt > because of edge clearance issues. As I recall, the rule is 2D from center > to edge (where D is diameter of hole). 2D of an AN3 is 3/8" which allows > proper clearance, but I feel I really need an AN4 to attach the tops of the > cabanes to the wing spar center section fittings. > > Here's what I can do: > > 1. Drill out to 1/4" for an AN4 anyway and disregard the edge clearance > recommendations. > > 2. Taper a 1x1" bar to 3/4 x 3/4 and use an AN4 in the 1" portion (this > method may look wierd) > > 3. Use AN3's to bolt the tops of the cabanes to the wing spar fittings. > (will 4 AN3's do the job of holding the wing center section in place?) > > 4. use 3/4" x 3/4" .080 wall 4130 steel instead of solid aluminum bar and > drill for AN4's > > 5. use 3/4 x 3/4" solid steel bar instead of aluminum and drill for AN4's (a > heavy solution) > > > No. 4 & 5 makes me wonder if edge clearance guidelines are different for > steel than aluminum...... are they?? > > I need advice! > > DJ Vegh > www.imagedv.com/aircamper > Mesa, AZ > N74DV > > > This email has been scanned for known viruses and made safe for viewing by Half Price Hosting, a leading email and web hosting provider. For more information on an anti-virus email solution, visit <http://www.halfpricehosting.com/av.asp>. > >


    Message 5


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    Time: 05:55:14 PM PST US
    From: "John Carmen" <jlcarmen@bellsouth.net>
    Subject: Re: cabane bolt edge clearance
    --> Pietenpol-List message posted by: "John Carmen" <jlcarmen@bellsouth.net> Jack and DJ I agree that two 1/4 inch bolts not cause any problems as Jack indicates, but I feel that using a 1/4 and then a 3/16 above it will distribute the load better and eliminate a stress riser. We do have two struts and not much of a moment arm at the attach points and predictable dynamic loads, thus distribution of load to the strut should be primary consideration, over brute strength. DJ, I think Jack's idea or mine would work just fine. Just make the hole close tolerance to eliminate any "wallowing" ----- Original Message ----- From: "Jack Phillips" <pietflyr@bellsouth.net> Subject: RE: Pietenpol-List: cabane bolt edge clearance > --> Pietenpol-List message posted by: "Jack Phillips" <pietflyr@bellsouth.net> > > DJ, > > I would go ahead and use the AN4 bolt. The 2D edge distance is primarily a > consideration for riveted joints, where the spreading rivet can cause > cracking of the base metal if too close to the edge. I pulled out my old > rivet installation standard from my days in the aerospace business and found > that for 1/4" rivets the standard edge distance was .50", but the > "Engineering Minimum" was .40" for material .064" thick and thicker, and the > "Inspection Minimum" was .37" for those conditions. The Engnieering Minimum > was the minimum value that could be specified on the drawing without having > a special signoff by the stress analysis group, but the inspection minimum > allowed the shop to screw up a little bit and go a little below the minimum > engineering standard. Bear in mind that this was for supersonic jet > fighters. I think it will be OK for a Pietengrega. > > As John Carmen pointed out, these bolts are loaded in shear (double shear, > actually) and I would be concerned about the aluminum piece shearing with a > 3/16" hole in it. Since the aluminum is considerably softer than the steel > bolt, the bolt would likely wallow a hole in the aluminum and allow you wing > to clunk up and down every time you hit a little turbulence. An AN4 bolt > offers 33% more shear area than an AN3. > > Good Luck, > > Jack > > > Keep in mind I am building a GN-1 which has a different method of attaching > cabanes to wing center section. > I'm having a bit of dilemma. I am using Skytec extruded aluminum > streamlined struts for cabanes and lift struts. The struts are hollow cored > with flats on the insides to allow a 3-6" piece of 3/4" x 3/4" solid > aluminum bar to be slipped in which allows you to terminate the ends by > having an inch or so of that bar stick out past the strut. You then bolt the > strut to the structure with that piece of bar. > Problem is, a 3/4" x3/4" solid aluminum bar only allows me an AN3 bolt > because of edge clearance issues. As I recall, the rule is 2D from center > to edge (where D is diameter of hole). 2D of an AN3 is 3/8" which allows > proper clearance, but I feel I really need an AN4 to attach the tops of the > cabanes to the wing spar center section fittings. > Here's what I can do: > 1. Drill out to 1/4" for an AN4 anyway and disregard the edge clearance > recommendations. > 2. Taper a 1x1" bar to 3/4 x 3/4 and use an AN4 in the 1" portion (this > method may look wierd) > 3. Use AN3's to bolt the tops of the cabanes to the wing spar fittings. > (will 4 AN3's do the job of holding the wing center section in place?) > 4. use 3/4" x 3/4" .080 wall 4130 steel instead of solid aluminum bar and > drill for AN4's > 5. use 3/4 x 3/4" solid steel bar instead of aluminum and drill for AN4's (a > heavy solution) > > > No. 4 & 5 makes me wonder if edge clearance guidelines are different for > steel than aluminum...... are they?? > I need advice! > DJ Vegh > www.imagedv.com/aircamper > Mesa, AZ > N74DV > >


    Message 6


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    Time: 06:05:58 PM PST US
    From: "Gene Rambo" <rambog@erols.com>
    Subject: Re: SNF
    --> Pietenpol-List message posted by: "Gene Rambo" <rambog@erols.com> Are we all going to be able to meet at the Piet forum tent again this year? I want to make sure I get together with everyone. I am going down Thursday, coming home Sunday. Gene ----- Original Message ----- From: "Richard Navratril" <horzpool@goldengate.net> Subject: Pietenpol-List: SNF > --> Pietenpol-List message posted by: "Richard Navratril" <horzpool@goldengate.net> > > Hey Guys > The camper is all packed and the stock of beer and taco chips has been checked and verified. I'm leaving in the camper tomorrow morning for Sun N Fun. Hope to see everybody again this year. I brought along a roll of yellow " caution - do not enter" tape. I'll try to mark off the camping area, same as last year. > > Dick N. > > do not archive > >


    Message 7


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    Time: 06:52:01 PM PST US
    From: clif <cdawson5854@shaw.ca>
    Subject: Re: cabane bolt edge clearance
    --> Pietenpol-List message posted by: clif <cdawson5854@shaw.ca> Why not use a 1" X 3/4" bar, chamfer the 1" sides to slide past the arc, front and rear, of the streamline. You could make it 11/4 or 1 1/2 " if you wanted. I just bought a piece of 6061-T6 3/4" X 4" for $2/lb ( US $1.35) And what about that Fortal aluminum? www.mousebar.com Clif.- Never fly anything with wings traveling faster than the fuselage. ----- Original Message ----- From: "John Carmen" <jlcarmen@bellsouth.net> Subject: Re: Pietenpol-List: cabane bolt edge clearance


    Message 8


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    Time: 07:19:04 PM PST US
    From: "Jack Phillips" <pietflyr@bellsouth.net>
    Subject: SNF
    --> Pietenpol-List message posted by: "Jack Phillips" <pietflyr@bellsouth.net> I'll be there Friday and Saturday. Jack -----Original Message----- From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Gene Rambo Subject: Re: Pietenpol-List: SNF --> Pietenpol-List message posted by: "Gene Rambo" <rambog@erols.com> Are we all going to be able to meet at the Piet forum tent again this year? I want to make sure I get together with everyone. I am going down Thursday, coming home Sunday. Gene


    Message 9


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    Time: 07:45:17 PM PST US
    From: "Ted Brousseau" <nfn00979@naples.net>
    Subject: Re: SNF
    --> Pietenpol-List message posted by: "Ted Brousseau" <nfn00979@naples.net> I noticed there are two Piet forums. Is there a difference? Ted ----- Original Message ----- From: "Gene Rambo" <rambog@erols.com> Subject: Re: Pietenpol-List: SNF > --> Pietenpol-List message posted by: "Gene Rambo" <rambog@erols.com> > > Are we all going to be able to meet at the Piet forum tent again this year? > I want to make sure I get together with everyone. I am going down Thursday, > coming home Sunday. > > Gene > > > ----- Original Message ----- > From: "Richard Navratril" <horzpool@goldengate.net> > To: <pietenpol-list@matronics.com> > Subject: Pietenpol-List: SNF > > > > --> Pietenpol-List message posted by: "Richard Navratril" > <horzpool@goldengate.net> > > > > Hey Guys > > The camper is all packed and the stock of beer and taco chips has been > checked and verified. I'm leaving in the camper tomorrow morning for Sun N > Fun. Hope to see everybody again this year. I brought along a roll of > yellow " caution - do not enter" tape. I'll try to mark off the camping > area, same as last year. > > > > Dick N. > > > > do not archive > > > > > >




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