spitzy

I think I may have found out the answer to my own question. CHP14 PG5 provides dimensions of the finished spar. These dimensions match what I built quite closely. Also, when I measured the cutout for the spar in my fuselage side pieces, it matched almost exactly what I built. It's still a mystery to me why my templates don't match what I built though!!! I must be missing something. When my next shipment of epoxy comes in I'm going to move forward with what I've got and cross my fingers. -Mike

Looks like I picked the wrong day to stop sniffing hardener!! For the main wings we are to build 5 jigs. The first 4 come in 4 pieces. The 5th one comes in two pieces. I've looked through all the drawings and cannot find a template for the 5th jig. Anyone know how to build that 5th jig? -Mike

I meant for and aft faces not top and bottom faces.

To verify the spare is shaped correctly before installing the shear web we are to utilize spar templates. Each template is to be loacated at a specific "BL location. My interpretation is that the templates should be placed along a specific "BL" line. This means the templates are all oriented parallel to each other as you go out from BL = 0, 37, 52, and 67.5. This means the templates are not perpendicular to the aft face of the spar at BL= 37, 52, and 67.5. If anyone remembers please verify I'm seeing this correctly. Also, please verify the depth of the spar caps will be 3" deep into the top and bottom faces at all locations. Thanks!

I got my jig and foam pieces cut perfectly but... Bonding the top of the box to the sides creates a gap which is filled with micro. Similar to the top, there is a gap between the bottom of the box and the sides. Adding these gaps results in an extra 1/8" distance between the top and bottom face in a few spots when checking with the spar cap templates. All other dimensions came out very acurate. I've not glassed any of the outside of the box. Is it critical to get this distance exact? Should I bother sanding to make up the difference or is there slop up an down when installing the spar into the plane?

Anybody remember how much Resin and Hardener went into the spar caps and shear web for this thing? Looks like I could go through a couple jugs... Thanks!

The instructions say we are to drill a 1" diameter hole in each of the spar bulkheads befor installing them to allow for cables etc... 1) None of the pictures in the book show these holes cutout. I wonder why. 2) Assuming we are to cut 1" holes do we cut them in the two ends, the two halfways, and the middle bulkhead for a total of 5 holes. 3) Assuming we are to cut the holes, why do we cut the foam first then do the layups? Thanks for your last reply Wayne. I'm going to do the inside layups per your suggestion.

Looks like it's going to be pretty tough to get a good layup in that box given all the right angles... Any suggestions or experiences with that?

How do those goofy looking rivits work that we are to use on the lift tab inserts? -Mike

In regards to saving the wing core: 1) Is it OK to glue foam where it's missing even if it is a perfect match. 2) I thought the best way to get a very close fitting piece of foam to "micro" on the trailing bottom edge was to nail the bottom contour checking template to the bottom piece scrap foam from my initial cut (this bottom piece is "the negative" of the resulting wing core). When I cut along the bottom contour template, I will shave a chunc of foam out that should perfectly match the bottom of my faulty wing core... 3) Would microing this piece in there reduce the strength? Doesn't seem like a problem because we are glueing piece of the wing together in ways that would be more likely to reduce the strength of the wing. Also per the Rutan video, the micro bond is stronger than the foam anyway. 4) Would microing in this piece screw up the trim of the plane by adding weight? Probably there is more error when you lay up the wings than this little bit of micro. Probably the density of foam and micro is very nearly the same anyway. 5) Would this interfere with the hing points some how? I'm using .032 SS safety wire per Rutan. Were can I get the iconal stuff?? I'm also going to experiment with a spring system. In case the wire stretches during the cutting process or incase the pipes rotate thus reducing wire tension.

Dag blamit! I had too much wire sag and or went too fast when turning the bottom aft corner of template "A" and "B". The wing core looked great right next to the template but I lost at least a 1/4" off the lower aft portion of the wing core moving towards the center. I was afraid of that happening and it did. Suggestions? I wonder if I need to modify the hot wire saw some how using a spring to keep the wire tight... Anyone else experience this? All I can figure is to go REALLY slow around that bend.

CHP 10 Figure 5 instructs us to cut a foam block to dimensions that don't allow for any excess foam around the A and B templates. Seems I'm going to throw away perfectly good foam that could have been used in the part prior to cutting out the airfoils. I've got just about the same width as my cutting wire if not a little less on the leading edge. Is there a reason why we are instructed to do this? Is it ok to move the templates aft past the trailing edge mark to allow for a little more error on the leading edge?

Just started cutting out large blocks of foam for my canard using the straigh templates I made. (masonite templates seem to work better than wood)... Anyway, I set the temperature per the video (using a small piece of foam to adjust cutting speed) but when it's time to cut the foam on a large piece there seems to be a pretty big sag in the middle of the wire. I don't like how long it takes for the middle of the wire to come out of the foam once each side is out. If I don't push the hot wire through the foam it REALLY seems to cut slow. Also, the foam cuts much slower as the piece to be cut gets bigger. Has anyone recorded an optimal current per span of cut using the .032 SS safety wire supplied by aircraft spruce? I'm making 70" cuts using a very acurate 3.6 amp dc current through the .032 wire. This is resulting in what I "think" is a slow cut...

Why would they corrode?

On the plans they show a dimension of 8.7" below the bottom edge of the top longeron. This represents the top edge of the rectangular cutout of 8.7 x5.5. Seems like this would introduce error into the location of these cuttouts given the potentially different locations of the longerons on each side of the plane. Any thoughts here? Seems like we should be measuring from the top of the fusalage forms...

I've completed the bulkheads and sides of the plane but don't have the space to assemble. So... I'm starting on the Canard. Before I start cutting into the foam with two people, I'd like to know if anyone has used a device like the following description. The cutting arm would be suspended from a pully for easy movement along the airfoil. Separate strings would be attached to the arm on each end of the wire and pulled with equal, constant, and adjustable force over the correct distance. A friend of mine did this with his model glider wings and said they come out much cleaner. I've also been playing with differnt gauge wire for cutting. The wire specifid in the kit requires a stout supply of current and seems to be less acurate than smaller gauge wire. Any thoughts or experience with this? Love, Mike

Thanks Guys! Did/are you going to layup the 4 layers of unidirectional along the entire length of the longerons and thus covering up the doubler in the front and the strange doubler all the way aft? If we are to glass the entire longeron it looks like we will need to do some shaping of the wood to allow the glass to lay flat...

I'm getting ready to layup the insides of the fuslage but can't figure out how to place the upper longerons. The upper longerons have a small piece of wood floxed to them about 5" from the front edge of the long wood strips. I assume they are only meant to provide support for the F28 Bulkhead. When looking at the plans it looks like you "eyeball" it so there would be an inch or so of this wood piece forward of F28. The longerons have a tapered doubler that will be installed facing down. It looks like if you moved the longeron and therefore this taper too far forward it would interfere with the controls. There are doublers installed almost all the way aft on the longerons. I have not been able to identify thier purpose. I can only guess they are used to provide bracing in front of the firewall to load from engine thrust. Given this assumption it seams important to place them correctly. Are we meant to "eyball" this installation based on the F28 bulkhead or is there a dimension I'm not seeing here?

Thanks for the information guys! If I'm lucky the details will be worked out when I'm ready for an engine. Why 2" inserts instead of 1"?

Hi All, I'm about 3 or 4 months into my Cozy project and am almost done with CH4. Pretty much just need to build the firewall and it's on to CH5. Before I get into building the firewall I want to verify I'm not creating re-work for myself should I end up using the Deltahawk engine instread of Lyoming. Any Cozys flying w/ Deltahawk engines? Any Gotchas I need to know about? Thanks, Mike