---------------------------------------------------------- Zenith701801-List Digest Archive --- Total Messages Posted Thu 08/13/15: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:20 AM - 7F3-2 Installation of Longeron Doubler (Perry Delano) 2. 12:36 PM - Re: 7F3-2 Installation of Longeron Doubler (Keith Ashcraft) 3. 02:14 PM - Re: 7F3-2 Installation of Longeron Doubler (pdelano@telus.net) ________________________________ Message 1 _____________________________________ Time: 09:20:50 AM PST US From: "Perry Delano" Subject: Zenith701801-List: 7F3-2 Installation of Longeron Doubler Hi All, I am a bit confused with the building manual for installation of the Longeron Doubler, 7F3-2. The skin is pre-drilled and the longeron has been back drilled to it. The doubler as it comes from Zenith is not pre-drilled. 1. I cannot figure out the purpose of the reference line, and if I could Cleco the doubler to the skin that would mean I'd have drilled the doubler and the job would be done?? 2. Also Because the bottom skin has a bit of a convex curve to it if I remove the clecos holding the forward section of the longeron to the skin it springs away from the skin edge. I have thought of drilling, countersinking and putting a couple of blind rivets in the skin to hold the longeron in place and then installing the doubler, but I don't think that was the intention. I believe I can clamp the doubler to the longeron with the piece of 0.016 sandwiched between them, and then having made a reference mark on th skin push the clamped assembly to this reference point and drill the holes in the doubler, but there would be a tension on the assembly which could result in oval holes or miss drilling especially when back drilling the doubler through the skin and longeron. ???? Any advice would be appreciated. Regards, Perry ________________________________ Message 2 _____________________________________ Time: 12:36:58 PM PST US From: Keith Ashcraft Subject: Re: Zenith701801-List: 7F3-2 Installation of Longeron Doubler Hi Perry, I'm not sure I can remember back to that portion, but.... Also remember that the SIDE skin will also get put between the doubler and longeron. I think this is the piece of .016" material they are talking about. Just make sure it is just a spacer and not pushed down into the bend of the longeron. I think you are on the right track, I think when I had things lined up, I then sandwiched the pieces between a scrap piece of wood screwed down to the work bench, and then finished drilling #20s in the correct places. Oh wait......I just saw it.... I don't know how I would go about it because the skin is pre-drilled.... I am scratch building so I drilled my own holes as a unit. I guess go with the clamping thing then turn it over and back drill through the doubler. The Photo guide might have been made before they put out pre-drilled materials.. It shows 04/2003, so I'm not sure when they started kits with pre-drilled holes. I think as long as things don't move, and are fixed as a unit, I think your drilling should be OK. Keith building my spars plane progress so far: https://picasaweb.google.com/ch701builder ********************************************************************************************** -------------------------------------------- On Thu, 8/13/15, Perry Delano wrote: Subject: Zenith701801-List: 7F3-2 Installation of Longeron Doubler To: zenith701801-list@matronics.com Date: Thursday, August 13, 2015, 10:19 AM Hi All, I am a bit confused with the building manual for installation of the Longeron Doubler, 7F3-2. The skin is pre-drilled and the longeron has been back drilled to it. The doubler as it comes from Zenith is not pre-drilled. 1. I cannot figure out the purpose of the reference line, and if I could Cleco the doubler to the skin that would mean Id have drilled the doubler and the job would be done??2. Also Because the bottom skin has a bit of a convex curve to it if I remove the clecos holding the forward section of the longeron to the skin it springs away from the skin edge. I have thought of drilling, countersinking and putting a couple of blind rivets in the skin to hold the longeron in place and then installing the doubler, but I dont think that was the intention. I believe I can clamp the doubler to the longeron with the piece of 0.016 sandwiched between them, and then having made a reference mark on th skin push the clamped assembly to this reference point and drill the holes in the doubler, butthere would be a tension on the assembly which could result in oval holes or miss drilling especially when back drilling the doubler through the skin and longeron. ???? Any advice would be appreciated. Regards, Perry ________________________________ Message 3 _____________________________________ Time: 02:14:56 PM PST US Subject: Re: Zenith701801-List: 7F3-2 Installation of Longeron Doubler From: pdelano@telus.net Thanks Keith, I just clamped everything down and together, I think like you were suggesting. Cofirmed longeron and skin holes were cocentric c/w .016 spacer and drilled. All still looks good and in hindsight the final holes have to go to 5/32 so any minor sub mm misalignment would get cleaned up. Thanks again. Perry Sent wirelessly from my BlackBerry device on the Bell network. 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