---------------------------------------------------------- Falco-List Digest Archive --- Total Messages Posted Mon 01/16/06: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:39 AM - Re: Introduction (Graeme Lean) 2. 03:50 AM - Cove Ribs (Rob Phillis) 3. 05:22 AM - Cove Ribs (Al Aitken) 4. 10:18 AM - Re: Cove Ribs (George Richards) ________________________________ Message 1 _____________________________________ Time: 01:39:53 AM PST US Subject: RE: Falco-List: Introduction From: "Graeme Lean" --> Falco-List message posted by: "Graeme Lean" Hi Al - welcome to the list. If I remember correctly - I installed the spar then the cove ribs and float sanded the whole mess to accommodate the skin. This seemed to work O'K for me - it wasn't easy, but then there's very little about building a falco that is easy. Cheers - Graeme --- On Sun 01/15, Al Aitken < votorschair@earthlink.net > wrote: From: Al Aitken [mailto: votorschair@earthlink.net] Subject: Falco-List: Introduction Hello everyone, Having been tipped off by my good Canadian buddy, Mike Wiebe, about the Falco List, I thought I would sign up and introduce myself to all of you. Many of you have heard of me in the Falco community, as I have had the opportunity to test fly a number of Falcos, and I am of course building one. I am the meticulous builder Mike referred to in his last post. I think he wanted to use the word anal, but he was kind. George Barrett, another builder suggested strongly to me that I install all of the cove ribs and the cove skin on the aft face of the aft wing spars before I glue the spars in place. At first that sounded like a good idea to me, but as I prepared to do that, I wondered how accurately I could place those cove ribs to ensure proper clearance with the aileron/flap assembly and also whether I would get the cove ribs at the right elevation on the aft spar to avoid sanding too much of the cove rib trailing edge strip away when I float sanded. So there you have it. I just joined the list and Im already whining for help. Anybody have any ideas on this? Al Aitken ________________________________ Message 2 _____________________________________ Time: 03:50:37 AM PST US From: "Rob Phillis" Subject: Falco-List: Cove Ribs --> Falco-List message posted by: "Rob Phillis" Al, Welcome to the list. If I may I'd like to add my 2 cents worth on the subject of when to install the cove ribs. I'm at the stage where I have a completed, but unskinned, airframe. I'm now in the process of installing all the internal systems which is much easier when you can reach in through the "skeleton" to get to things. I too pondered over the cove rib issue but have decided, (maybe incorrectly, time will tell) to leave them until after I've skinned the wings. The top skins are, from memory, 2mm and 1.5mm ply, which is very stiff over a short span. It is my intention to fit them with a considerable amount protruding past the aft spar, then trim the skin to provide a nice straight line and clear of the flaps / ailerons by the minimum amount, probably 5mm or so. The skins will only be cantilevered around 60 - 70mm unsupported during this process and given their thickness I can't imagine they will be at all floppy. It should then be a simple matter to shape the cove ribs to suit and glue them in place under the top skin, then install the cove rib trailing edge and skin to close things out. We shouldn't lose sight of the fact that the wing skin is the important item here, the cove ribs are just there to provide it with some support for the very small amount of overhang it has past the rear spar. Given the inherent stiffness of the ply it could be argued that the cove ribs are almost unnecessary . . but I'm not brave enough to advocate leaving them off all together! Just for the record, those in cold climates may be alarmed by my comment above regarding a 5mm clearance between the skin and the control surfaces, but in this part of the world, and at the altitudes I'll be flying, icing is not a concern. Anyway, that's my plan - if it doesn't work I'll be sure to let you all know! Cheers, Rob -- ________________________________ Message 3 _____________________________________ Time: 05:22:57 AM PST US From: "Al Aitken" Subject: Falco-List: Cove Ribs The consensus seems to be to wait until after the aft spar is in place before cluing on the cove ribs. That is more in line with my thinking as it will ensure more accurate placement of those ribs. I like Rob Phillis's idea of waiting until after the wing skins are glued on. That would allow waiting until the wing is out of the jig and mounted in the fuselage jig, making it much easier to work with the cove ribs without having to lay on my back. Thanks to both Rob Phillis and Graeme Lean for their thoughts on this. AL Aitken ________________________________ Message 4 _____________________________________ Time: 10:18:10 AM PST US From: George Richards Subject: RE: Falco-List: Cove Ribs --> Falco-List message posted by: George Richards One minor issue with shaping the cove ribs is the fact that the hinge bolts protrude from the spar making it a little difficult to use a long rod shaped sander in the lower half of the ribs. Didn't have any impact on me since I went conventional Falco and didn't skin them. If you didn't have lower wing skins on you could leave the bolts out while sanding cove ribs.. The top wing skins are supposed to be last but I don't see any real difference. GR's 50c worth www.falco.co.nz -----Original Message----- From: owner-falco-list-server@matronics.com [mailto:owner-falco-list-server@matronics.com]On Behalf Of Rob Phillis Sent: Tuesday, 17 January 2006 12:50 a.m. Subject: Falco-List: Cove Ribs --> Falco-List message posted by: "Rob Phillis" Al, Welcome to the list. If I may I'd like to add my 2 cents worth on the subject of when to install the cove ribs. I'm at the stage where I have a completed, but unskinned, airframe. I'm now in the process of installing all the internal systems which is much easier when you can reach in through the "skeleton" to get to things. I too pondered over the cove rib issue but have decided, (maybe incorrectly, time will tell) to leave them until after I've skinned the wings. The top skins are, from memory, 2mm and 1.5mm ply, which is very stiff over a short span. It is my intention to fit them with a considerable amount protruding past the aft spar, then trim the skin to provide a nice straight line and clear of the flaps / ailerons by the minimum amount, probably 5mm or so. The skins will only be cantilevered around 60 - 70mm unsupported during this process and given their thickness I can't imagine they will be at all floppy. It should then be a simple matter to shape the cove ribs to suit and glue them in place under the top skin, then install the cove rib trailing edge and skin to close things out. We shouldn't lose sight of the fact that the wing skin is the important item here, the cove ribs are just there to provide it with some support for the very small amount of overhang it has past the rear spar. Given the inherent stiffness of the ply it could be argued that the cove ribs are almost unnecessary . . but I'm not brave enough to advocate leaving them off all together! Just for the record, those in cold climates may be alarmed by my comment above regarding a 5mm clearance between the skin and the control surfaces, but in this part of the world, and at the altitudes I'll be flying, icing is not a concern. Anyway, that's my plan - if it doesn't work I'll be sure to let you all know! Cheers, Rob --