Originally posted by JimD
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1:4 1928 RRG Professor
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The outer panel was taken off the board so that the bottom edges of the ribs could be sanded fair. The ribs for the other panel were put next to their counterparts so that these could be sanded to match. Other than the nose portions being a little 'fat' the ribs match up nice! That's a good testament to the drafting exercise early on! Next, the outer panel and inner panel were laid together inverted so that the bottom spar notches could be cut into the outer panel using the inner as a guide or reference. A straight edge was used to guide the saw and a scrap piece of spar stock was used to guarantee the fitment as the notches were sanded to the proper depth. Remember... the spar gets thinner toward the tip by design. The wing rod tube was let into the ribs. A jig was made to guide the 'hole cutter'. The 'hole cutter' is just brass tube with serrated edges on one end. The serrations were made with a Dremel cut-off wheel. The jig just keeps the cutter at the proper depth. The spar temporarily placed was used as a guide for the 'hole cutter'. When satisfied this was pulled off the board so I could start on the other outer panel. More work will get done to these later.
The wing tube and joiner rod are in place in the last picture. More to come.Last edited by ARUP; 03-05-2018, 02:02 AM.
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First pics shows the beginning of ribs to LE and TE assembly. It's pretty fragile and 'floppy' at this stage! The second pic shows the center and outer panels being aligned in order to cut spar slots. The third pic shows straight edge being used to cut one side of spar slots. The scrap spar will be used to guide the saw for the other side and for proper depth of the slot. Once the spar was dry fitted it was used to guide the 'hole cutter' for the wing rod receiver tube. The fourth pic shows packing fitted to the wing tube then the packing and spar were epoxied in place. The straight edge was used to make sure the spar stayed flat. The fifth pic shows outer panel connected to center panel.with joiner tube. Time to build the other panel.
More...
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The first outer panel was used as a guide to make the other. The root ribs were all made together so are perfect with respect to each other. Misalignment errors do creep into the build so to make sure that doesn't happen with respect to the second outer panel dimensions were taken off the first and transferred to the second. The spar to LE is 11mm at the tip so this was used for the second panel. A straight edge from this tip point to the spar slot at the root was then fixed to the panel then the panel was aligned to the inner one making sure the spars will be aligned for each. The first pic shows packing being fabricated. This was done after dry fitting the spar and using the 'hole cutter' for the wing tube. The groove was sanded into the edge then the cut was made to fit the depth from the tube to the spar. Just as with the first outer panel the packing was epoxied along with the spar. The straight edge was used to make sure the spar stayed flat. The last pics just show the epoxy curing.
Next to put onto the panels is the bottom portion of the 'D' tube sheeting. After this the panels will be placed onto a jig for proper washout before fitting the top spar and closing the 'D' tube with sheeting.
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Thank goodness for a nice 'stash' of Ambroid! It is great for edge gluing balsa because, after sanding, the joint 'disappears'! Sheeting was made up from 1/16" balsa for the outer panels. The piece near the tip was put onto the wing first. There is a bit of scrap balsa laminated onto one of the ribs so the sheeting has a place to land. Once the glue dries the other part of the sheeting will get put onto it.
Buenas noches!
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We got a snow surprise! It rained and the wind blew, then it sleeted and then the snow stuck to all of that! It sure was pretty! I slipped the outer panels onto the inner for grins. That's a lotta wing area! Currently, the aileron spars are getting 'cut in' to the structure and a neat method will drive the ailerons to use cables in scale locations without the need for crummy servo hatches spoiling the 'scale look'! It's all about 'smoke and mirrors'... baby!
Gute nacht!
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The aileron false spar slots were cut and the false spars were let into the structure. The outer portion of the spars are thinner stock because the aileron (and wing) tapers in chord and thickness. After this was done the wing was put back onto the board top side up and with the wash out jig in place so that the upper spar and wing tube packing could be epoxied in place. A bit of masking tape acts as a depth-of-cut gauge for the slots. The same method of using a straight edge to guide the saw cuts was used. A scrap of appropriately wide scrap was used to make the slots an interference fit for the spar so even if the spar isn't dead straight it will be after being let into the structure.
The aileron false spar is in two parts so that separating the two will be easier. They are pinned together so that they could be glued to the structure as a unit. More to come.
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The outer panels have their upper and lower spars along with their lower aileron spars installed. Next will be the 'cutting-in' of the upper aileron spars into the structure so not much of a photo-op, there. It would just be a repeat of the previous stuff! The shear webbing is getting installed. That is a visually boring job but a 'cute' little device was fabricated to clamp the webbing in place while the epoxy cures. This pair of doo-dads were made necessary because the wing tubes are a bit wider than the spars. The webs have to bend around the wing tubes a tiny bit. The spar edges were sanded fair to the wing tubes to get as tight a fit as possible. The root end of the spar will be under the most stress, I reckon. The shear webbing is cut 'on the bias' as per full scale practice and is probably over kill but that's all right! The first pic shows epoxy curing while the 'doo-dads' were holding the shear webs in place with the aid of a clamp. The next pic shows the root end shear webs in place with the doo-dads and loose shear webs lying about. Two tiny thin spacers keep the doo-dads from getting stuck to the sheeting in case some epoxy squeezes out.
The next post will be when the shear webbing and upper aileron spars are done. Cheers!
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I thought you already were missing part of your ear Michael ??? I must have mistaken that...
kevin
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