Original Posted By: steamlaunch(at)softhome.net
Mike,A few months ago, there was a thread about making cooling eyebrows fromdead-soft 0.24 aluminum. I know what Cub eyebrows look like externally butI don't have easy access to one to inspect and measure--could you give us aquick description of your design process? What, if any internal baffles arethere? Externally, each part looks like it's two pieces. Are they rivetedtogether? What do the hold-down clamps attach to? Are there any questionsI forgot to ask?Thanks,Gene HubbardSan Diego, with woodwork done and trying to get oriented to sheetmetal.________________________________________________________________________________
Pietenpol-List: Cooling Eyebrows
Re: Pietenpol-List: Cooling Eyebrows
Original Posted By: "Hubbard, Eugene"
Gene,Do not clamp on the aluminum, instead attach a steel bracket and rivet the or screw the aluminum to the bracket. Matt Hubbard, Eugene writes: > > Mike, > > A few months ago, there was a thread about making cooling eyebrows from> dead-soft 0.24 aluminum. I know what Cub eyebrows look like externally but> I don't have easy access to one to inspect and measure--could you give us a> quick description of your design process? What, if any internal baffles are> there? Externally, each part looks like it's two pieces. Are they riveted> together? What do the hold-down clamps attach to? Are there any questions> I forgot to ask? > > Thanks,> Gene Hubbard> San Diego, with woodwork done and trying to get oriented to sheetmetal. > > > > > > ________________________________________________________________________________
Gene,Do not clamp on the aluminum, instead attach a steel bracket and rivet the or screw the aluminum to the bracket. Matt Hubbard, Eugene writes: > > Mike, > > A few months ago, there was a thread about making cooling eyebrows from> dead-soft 0.24 aluminum. I know what Cub eyebrows look like externally but> I don't have easy access to one to inspect and measure--could you give us a> quick description of your design process? What, if any internal baffles are> there? Externally, each part looks like it's two pieces. Are they riveted> together? What do the hold-down clamps attach to? Are there any questions> I forgot to ask? > > Thanks,> Gene Hubbard> San Diego, with woodwork done and trying to get oriented to sheetmetal. > > > > > > ________________________________________________________________________________
RE: Pietenpol-List: Cooling Eyebrows
Original Posted By: steamlaunch(at)softhome.net [mailto:steamlaunch(at)softhome.net]
Matt,I think I'm a couple of steps behind you. Just about all I know about theeyebrow structure is that it is open in the front, closed in the back, andis trapped by the valve cover screws on the outside. From pictures, itappears that there is some sort of clamp that fits between the cylinders tohold the structure in place. I have no clear understanding of the internalstructure, the baffling between the cylinders or of how they're held down atthe crankcase end. If someone could e-mail me a digital photo of the insideof an eyebrow, it would answer a lot of questions.I guess my first question is where the bracket is attached?Gene-----Original Message-----
Matt,I think I'm a couple of steps behind you. Just about all I know about theeyebrow structure is that it is open in the front, closed in the back, andis trapped by the valve cover screws on the outside. From pictures, itappears that there is some sort of clamp that fits between the cylinders tohold the structure in place. I have no clear understanding of the internalstructure, the baffling between the cylinders or of how they're held down atthe crankcase end. If someone could e-mail me a digital photo of the insideof an eyebrow, it would answer a lot of questions.I guess my first question is where the bracket is attached?Gene-----Original Message-----
Re: Pietenpol-List: Cooling Eyebrows
Original Posted By: "Hubbard, Eugene"
Gene, Matt, I copied mine from an old Cub. got the old sheet of oak tag( sorry todate myself) and masking tape, and went to work.I did a "rubbing" of the rear area, and then a outline of the large upperarea. Then kind of fudged the rest. Made 4130 tabs in two places on eachto catch the top screws on the valve covers.for the inboard bracket, made it out of fairly thin 4130 plate. First madeit out of alum. but my AP said no to that. so redid them in 4130 and addednutplates to hold the eyebrows down.Made them to contour over the bases of the cyl. and catch the top nut oneach cyl.I only had non soft alum ( forget what grade) little harder to work withthough. My AP showed me the knack of leaving an extra 1/4 in. on thepattern and rolling a piece of 1/16" welding rod into the edge. Gives anice appearance that won't crack.Even had to dimple out the top rear for plug clearance.Let me know and I can send pics. but they're not that much detailwalt----- Original Message -----
Gene, Matt, I copied mine from an old Cub. got the old sheet of oak tag( sorry todate myself) and masking tape, and went to work.I did a "rubbing" of the rear area, and then a outline of the large upperarea. Then kind of fudged the rest. Made 4130 tabs in two places on eachto catch the top screws on the valve covers.for the inboard bracket, made it out of fairly thin 4130 plate. First madeit out of alum. but my AP said no to that. so redid them in 4130 and addednutplates to hold the eyebrows down.Made them to contour over the bases of the cyl. and catch the top nut oneach cyl.I only had non soft alum ( forget what grade) little harder to work withthough. My AP showed me the knack of leaving an extra 1/4 in. on thepattern and rolling a piece of 1/16" welding rod into the edge. Gives anice appearance that won't crack.Even had to dimple out the top rear for plug clearance.Let me know and I can send pics. but they're not that much detailwalt----- Original Message -----
Re: Pietenpol-List: Cooling Eyebrows
Original Posted By: "walter evans"
Oh, forgot to say that I put auto type plugs in the A-65 with some snazzyspark plug wire that I got from an antique magneto co. Very reasonable.walt----- Original Message -----
Oh, forgot to say that I put auto type plugs in the A-65 with some snazzyspark plug wire that I got from an antique magneto co. Very reasonable.walt----- Original Message -----
Re: Pietenpol-List: Cooling Eyebrows
Original Posted By:> "Hubbard, Eugene"
Mr. Evans has given a clear picture of where you are going, sorry my first email was so perscriptive. And incomplete. The reason you do not want to clamp the aluminum under the valve cover screw is it will over time with heat and vibration squish out from under the head of the fastener and cause an oil leak. Ergo clamp steel tabs in this posistion and fasion your plenum to fit. Is this for a continental Lycoming or Corvair? The latter would require retaining the tins under the cylinders pr WW directions! Good luck! Matt walter evans writes: > > Gene, Matt,> I copied mine from an old Cub. got the old sheet of oak tag( sorry to> date myself) and masking tape, and went to work.> I did a "rubbing" of the rear area, and then a outline of the large upper> area. Then kind of fudged the rest. Made 4130 tabs in two places on each> to catch the top screws on the valve covers.> for the inboard bracket, made it out of fairly thin 4130 plate. First made> it out of alum. but my AP said no to that. so redid them in 4130 and added> nutplates to hold the eyebrows down.> Made them to contour over the bases of the cyl. and catch the top nut on> each cyl.> I only had non soft alum ( forget what grade) little harder to work with> though. My AP showed me the knack of leaving an extra 1/4 in. on the> pattern and rolling a piece of 1/16" welding rod into the edge. Gives a> nice appearance that won't crack.> Even had to dimple out the top rear for plug clearance.> Let me know and I can send pics. but they're not that much detail> walt> ----- Original Message -----
Mr. Evans has given a clear picture of where you are going, sorry my first email was so perscriptive. And incomplete. The reason you do not want to clamp the aluminum under the valve cover screw is it will over time with heat and vibration squish out from under the head of the fastener and cause an oil leak. Ergo clamp steel tabs in this posistion and fasion your plenum to fit. Is this for a continental Lycoming or Corvair? The latter would require retaining the tins under the cylinders pr WW directions! Good luck! Matt walter evans writes: > > Gene, Matt,> I copied mine from an old Cub. got the old sheet of oak tag( sorry to> date myself) and masking tape, and went to work.> I did a "rubbing" of the rear area, and then a outline of the large upper> area. Then kind of fudged the rest. Made 4130 tabs in two places on each> to catch the top screws on the valve covers.> for the inboard bracket, made it out of fairly thin 4130 plate. First made> it out of alum. but my AP said no to that. so redid them in 4130 and added> nutplates to hold the eyebrows down.> Made them to contour over the bases of the cyl. and catch the top nut on> each cyl.> I only had non soft alum ( forget what grade) little harder to work with> though. My AP showed me the knack of leaving an extra 1/4 in. on the> pattern and rolling a piece of 1/16" welding rod into the edge. Gives a> nice appearance that won't crack.> Even had to dimple out the top rear for plug clearance.> Let me know and I can send pics. but they're not that much detail> walt> ----- Original Message -----
RE: Pietenpol-List: Cooling Eyebrows
Original Posted By: owner-pietenpol-list-server(at)matronics.com
One of the big cautions is to never, I mean NEVER, put anything that issofter than 4130 steel under a cylinder hold down nut. Better yet,literature, including SBs from both Lycoming and Continental as well as theBingelis (Firewall Forward page 129) and EAA How To books, implore you notto put ANYTHING under the hold down nuts. The reason? Vibration andcyclical stresses will tend to loosen the nut or allow the material betweenthe nut and the cylinder base to squeeze out, lowering the tightness of thenut on the stud and allowing the nut to loosen up. History has shown thatwhen one nut loosens up then the others will too. It is just a matter oftime.How can it ever happen? Just ask my buddy Danny Doyle of McKinney, Texaswho had a cylinder loosen up in flight. By the time he made the ground, thecase and the cylinder were toast. And that was at idle power. He says toalso always use PAL nuts on each stud as an extra precaution. If you visithis strip, he will do a subtle inspection of your engine. If he sees you donot have PAL nuts, he will pull a packaged set from his pocket and GIVE themto you, making you promise to put them on.Now I know that you don't have much of a choice with the eyebrows so goahead and use the cylinder hold down studs as an attach point but definitelymake the attach fittings out of 4130/4140. This material is comparable inhardness to the 4140 the cylinder barrels are made of.Also it is prudent to make some 1/4 circles back to back that can beattached to the lower side between the two cylinders on each side to helpguide the air through the fins on the underside of the cylinder. Likewise,the rear of the Cub-style air scoops should wrap around the back of thecylinder to a point at about the 7:30 position. This should attach with alittle spring to the rear of the 1/4 circle just ahead of it. See Bingelis'Firewall Forward page 127. This is all to keep the cooling uniform. It isimperitive that the air go through the fins and nut just past the cylinderswith an offhand chance the fins might see enough of it. Your engine mightappear to be running well now but what about in 600 hrs?Go look at the cylinder underside of a taylorcraft or a cessna 140/150 tosee a really good way to keep the air in the fins and not around them.Gaps in the baffling are to be kept to a 1/16" maximum. Also, it is wise togive the baffling a good shove in the direction of the air load to see howfar it moves away from its intended placement. You do not want air to takea least path of resisitance around the fins. The baffling must be held inplace to force the air THROUGH the fins.It is also a good idea to direct undisturbed cold air along the bottom ofthe case with the intent to spill it onto the oil sump to enhance cooling.See Bingelis' Firewall Forward page 131 for a tray to accomplish this orlook at a taylorcraft or cessna 140/150. Otherwise you have to rely on veryturbulent air that is already warmed by the cylinders to cool your oil. Notvery good for flying to Brodhead in July.chris bobka-----Original Message-----
One of the big cautions is to never, I mean NEVER, put anything that issofter than 4130 steel under a cylinder hold down nut. Better yet,literature, including SBs from both Lycoming and Continental as well as theBingelis (Firewall Forward page 129) and EAA How To books, implore you notto put ANYTHING under the hold down nuts. The reason? Vibration andcyclical stresses will tend to loosen the nut or allow the material betweenthe nut and the cylinder base to squeeze out, lowering the tightness of thenut on the stud and allowing the nut to loosen up. History has shown thatwhen one nut loosens up then the others will too. It is just a matter oftime.How can it ever happen? Just ask my buddy Danny Doyle of McKinney, Texaswho had a cylinder loosen up in flight. By the time he made the ground, thecase and the cylinder were toast. And that was at idle power. He says toalso always use PAL nuts on each stud as an extra precaution. If you visithis strip, he will do a subtle inspection of your engine. If he sees you donot have PAL nuts, he will pull a packaged set from his pocket and GIVE themto you, making you promise to put them on.Now I know that you don't have much of a choice with the eyebrows so goahead and use the cylinder hold down studs as an attach point but definitelymake the attach fittings out of 4130/4140. This material is comparable inhardness to the 4140 the cylinder barrels are made of.Also it is prudent to make some 1/4 circles back to back that can beattached to the lower side between the two cylinders on each side to helpguide the air through the fins on the underside of the cylinder. Likewise,the rear of the Cub-style air scoops should wrap around the back of thecylinder to a point at about the 7:30 position. This should attach with alittle spring to the rear of the 1/4 circle just ahead of it. See Bingelis'Firewall Forward page 127. This is all to keep the cooling uniform. It isimperitive that the air go through the fins and nut just past the cylinderswith an offhand chance the fins might see enough of it. Your engine mightappear to be running well now but what about in 600 hrs?Go look at the cylinder underside of a taylorcraft or a cessna 140/150 tosee a really good way to keep the air in the fins and not around them.Gaps in the baffling are to be kept to a 1/16" maximum. Also, it is wise togive the baffling a good shove in the direction of the air load to see howfar it moves away from its intended placement. You do not want air to takea least path of resisitance around the fins. The baffling must be held inplace to force the air THROUGH the fins.It is also a good idea to direct undisturbed cold air along the bottom ofthe case with the intent to spill it onto the oil sump to enhance cooling.See Bingelis' Firewall Forward page 131 for a tray to accomplish this orlook at a taylorcraft or cessna 140/150. Otherwise you have to rely on veryturbulent air that is already warmed by the cylinders to cool your oil. Notvery good for flying to Brodhead in July.chris bobka-----Original Message-----
Re: Pietenpol-List: Cooling Eyebrows
Original Posted By: Michael D Cuy
RE: Pietenpol-List: Bingelis on eyebrows
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Mike,Hard aluminuam ain't hard enough, please. Use the 4130/4140. It is only amatter of time...Chris Bobka-----Original Message-----
Mike,Hard aluminuam ain't hard enough, please. Use the 4130/4140. It is only amatter of time...Chris Bobka-----Original Message-----
Pietenpol-List: Bingelis on eyebrows
Original Posted By: "Gary McNeel, Jr."
> Pietenpol-List: Bingelis on eyebrows
Original Posted By: Michael D Cuy
Pietenpol-List: Cooling Eyebrows
Original Posted By: Isablcorky(at)aol.com
What is the thinnest 4130 that brackets can be made of that fasten to the cylinderattach studs, and are they placed between the nuts and the palnuts?DickG. in Ft. Myers________________________________________________________________________________
What is the thinnest 4130 that brackets can be made of that fasten to the cylinderattach studs, and are they placed between the nuts and the palnuts?DickG. in Ft. Myers________________________________________________________________________________
Re: Pietenpol-List: Cooling Eyebrows
Original Posted By: Ken Rickards
Subject: Re: Pietenpol-List: Cooling EyebrowsI would think about .025 to .032 would be plenty strong as you have a flange for added strength. Mind is bolted between the case and the hold down bolt. I have no pal nuts.Corky________________________________________________________________________________
Subject: Re: Pietenpol-List: Cooling EyebrowsI would think about .025 to .032 would be plenty strong as you have a flange for added strength. Mind is bolted between the case and the hold down bolt. I have no pal nuts.Corky________________________________________________________________________________
RE: Pietenpol-List: GN-1 vs. aircamper
Original Posted By: travis battreal [mailto:travisbattreal(at)yahoo.com]
Both the GN1 and the Pietenpol have steel fuse versions. Although bothAircraft look similar there are some differences. The wing construction inthe GN1 is different, some may say overbuilt, the wing on the Pietenpol ismoveable, fuse construction is also different with the GN1, plans callingfor the plywood sides to extend beyond the rear cockpit to the tail post.DJ Vegh has eliminated this on his GN1 to save weight and I will be doingthe same thing. The GN1 fuse is longer than the original Pietenpol, but thePietenpol also comes in a long fuse version. The GN1 also allows for the useof Cub parts, fuel tank, main gear etc. No matter which way you go you willend up will a classic homebuilt.Ken -----Original Message-----
Both the GN1 and the Pietenpol have steel fuse versions. Although bothAircraft look similar there are some differences. The wing construction inthe GN1 is different, some may say overbuilt, the wing on the Pietenpol ismoveable, fuse construction is also different with the GN1, plans callingfor the plywood sides to extend beyond the rear cockpit to the tail post.DJ Vegh has eliminated this on his GN1 to save weight and I will be doingthe same thing. The GN1 fuse is longer than the original Pietenpol, but thePietenpol also comes in a long fuse version. The GN1 also allows for the useof Cub parts, fuel tank, main gear etc. No matter which way you go you willend up will a classic homebuilt.Ken -----Original Message-----
RE: Pietenpol-List: Cooling Eyebrows
Original Posted By: Dick and Marge Gillespie [mailto:dickmarg(at)peganet.com]
Dick,I made an angle of .032 4130 about 3/4" on a side that spanned the fore andaft cylinder. I put this between the nuts and palnuts with the flangefacing the centerline of the engine (easy way to put it on). I then mountedfive rivnuts to screw the eyebrow itself onto. This helps support theeyebrow itself. It hasn't flown yet, but it looks official.Gene-----Original Message-----
Dick,I made an angle of .032 4130 about 3/4" on a side that spanned the fore andaft cylinder. I put this between the nuts and palnuts with the flangefacing the centerline of the engine (easy way to put it on). I then mountedfive rivnuts to screw the eyebrow itself onto. This helps support theeyebrow itself. It hasn't flown yet, but it looks official.Gene-----Original Message-----
Re: Pietenpol-List: Cooling Eyebrows
Original Posted By: "Dick and Marge Gillespie"
Does everyone roll welding rod wire in the exposed edges of the eyebrows?Guess everyone does, but I thought I'd bring it up again, since the threadstarted again. also used it in all the openings of the engine cowl.Makes for a really nice job.walt evansNX140DL----- Original Message -----
Does everyone roll welding rod wire in the exposed edges of the eyebrows?Guess everyone does, but I thought I'd bring it up again, since the threadstarted again. also used it in all the openings of the engine cowl.Makes for a really nice job.walt evansNX140DL----- Original Message -----
RE: Pietenpol-List: Cooling Eyebrows
Original Posted By: owner-pietenpol-list-server(at)matronics.com
I did it on the cooling eyebrows, since they were made of 3003-H14 (soft)aluminum. My cowling is .025" 2024-T3 so I didn't roll the wires in theedges of the cutouts on the cowling. By the way, the December 1999 issue ofSport Aviation (the one with the article about Mike Cuy's plane) has a verygood description of how to do this and a lot of other metal workingtechniques in the article on building a cowling for a Curtiss Robin.Jack -----Original Message-----
I did it on the cooling eyebrows, since they were made of 3003-H14 (soft)aluminum. My cowling is .025" 2024-T3 so I didn't roll the wires in theedges of the cutouts on the cowling. By the way, the December 1999 issue ofSport Aviation (the one with the article about Mike Cuy's plane) has a verygood description of how to do this and a lot of other metal workingtechniques in the article on building a cowling for a Curtiss Robin.Jack -----Original Message-----
Re: Pietenpol-List: Cooling Eyebrows
Original Posted By: "walter evans"
WaltI used copper wire rolled into mine.Dick N.----- Original Message -----
WaltI used copper wire rolled into mine.Dick N.----- Original Message -----