dle's Oz Build

[colospace]

Dave,
If you let the Hysol set up just a few minutes, you can then smooth out the bond fillets with a finger wetted in IPA.

[jiott]

I agree with Gary, I think most fillets should get finished off with your finger. It not only gives a nice looking consistent fillet (and a messy finger), but pushes the Hysol into all the little cracks and crevices for a good bond. Alcohol does a great job of cleaning up unwanted areas, fingers, etc.

I personally wouldn't spend any time squaring off that triangular area on the bottom of the rudder. Its not seen, and the fabric will conform fine to the triangle.

[David47]

Dave S, thanks for the photos - the way you've finished off the bottom of the rudder is exactly what I was thinking. But I hadn't thought about finishing of the inboard section of the elevator like that. Very nice job. I'll plagiarise your design, hope you don't mind. So I guess it's back to preschool with the finger in the sticky stuff. Thanks for the input Dave, Gary, Jim, very much appreciated.

[David47]

Another productive weekend. The weathers starting to get colder here in the southern parts of Australia so we all rug up like Penguins ... I'm still bonding some remaining ribs onto the elevator and started on the fixed fin ribs. Not sure if I've messed up here but the lowermost ribs shown in the manual show two seperate ribs. I think I've sorted it by cutting one of the ribs in two and bonding the sections either side of the t/wheel forward bolt attach point. My concern is that the outside profile of the forward rib is inside the adjacent tube. This doesn't look right to me as when the fabric is wrapped in this area, there'll be a weird crease. The photo shows what I mean. I can fix this by bonding some spare rib stiffener sections either side to get a cleaner fabric line. Anyone come across this before or is it just me ... ?

Set the low fuel warning system tank and hardware in place and lock wired the lowermost fuselage tube in position. Rough cut the seat pans and cut the harness slots. Think I'll put an edging on these as they'll abrade the seat belt material.

Fitted up the rudder f/glass LE and trimmed so that the aft edges fair into the recessed section of the ribs. It all seemed to come together well, with a minimum of gap between the rib LE and the glass LE. Slots for the hinge points aren't cut at this stage. Did the same for the fixed fin glass TE and cut the slots for the rod end hinge points. Probably got a bit over excited using the Dremel and cut the slots a little more than needed, so I'll fill with my now favourite adhesive, Hysol 4960 !. I've included a photo of my over exuberance so that others that come later don't repeat the same mistake (Lowermost cutout shown as its the worst ... I should have just cut enough for the rod end hinge and the rudder stop arms). A question that comes out of this though is the gap between the rudder LE and the fin TE fairings. I'm guessing about 1/8" is quite possible without too much trouble - wouldn't want any less - but typically what are other folks setting this at ?. I'm sure I've seen this discussion elsewhere, just can't recall on who's thread it was.

Other than the Dremel sage and couple of other transgressions, progress is happening without too much drama - so far ....

[jiott]

As has been mentioned before, the proper gap between the two rudder fiberglass fairings is difficult to do before covering and paint. You will end up with multiple layers of fabric and paint on these surfaces and will probably need more gap than you think. I think the best way is to make a reasonable guess at the gap then don't bother with it until covered and painted. THEN mount the rudder and set the rod ends for proper gap. When all this looks good, THEN trim the steel rudder stop plate for your + & - 25 degree travel. If you trim it before, the travel stops will be too short if you have to increase the gap for clearance.

[efwd]

AARrggh. The manual says nothing about that but that makes total sense. Too Late.
Wonder if I will have more rudder authority? Actually, I don't even have but one layer of Oratex on the rudder fiberglass leading edge and no fabric in the center of the vertical trailing edge where the tolerance counts. I attributed the need to adjust to simple temperature change. I cant imagine that I had the gap so close that it would not have accommodated that one layer of glue and fabric.
Regarding the fiberglass cutouts, I found I had to enlarge mine so that tools would fit to tighten the attaching hardware. I believe your going to be fine as long as they aren't too small to get a wrench in.
Eddie

[rosslr]

Hi David,

Don't think anyone has directly answered you question re the bottom rib and having to cut it in 2. Yes, we did too. and yes, the fwd part sits inside the frame. I had a look on ours and when the fabric is on and stretched it just forms a smooth curve - not to worry. I text you a pic of ours.

Jim gives good advice about the rudder - worry about it later! And I cut the angles at that stage too - but there is an easy fix later.

great progress!

cheers

r

[David47]

Thanks Jim, what you say makes total sense and I'm sure this must have been discussed years earlier ad nauseous .... The setup of the rudder to fin in the manual gives dimensions for the top and bottom hinge points at the stage I'm at right now. I think it would be better to wait as you suggest and get the fabric on and then get the gap set. I can also see how it would be easty to cut the 25 degree angles too soon ..... if you've done that Eddie then looks like Ross has the solution. And I'll do an access test for tools for adjusting the locknuts at the hinge points and fill the excess removal of the fairing using adhesive.

Thanks for the text picture of the lower rib Ross. Good to know it won't look odd.

[jiott]

You guys using Oratex should have much less problem with the rudder gap changing after cover and paint because the Oratex is much thinner and of course no paint.
Tools for mounting the rudder, what a vivid memory! Its a bear getting those nuts tightened, but very doable with patience. I recall I had to grind some notches on my wrench in order to get enough swing. Fortunately, just slip the bolts in and don't worry about the nuts when you are taking it on and off while adjusting the gap and travel stops.
Some guys go more than the suggested 25 degrees, just so the rudder at full travel doesn't contact the elevator. I see nothing wrong with this approach, getting as much rudder authority as possible. I will say that I used 25 degrees and that gives HUGH rudder authority; I have never wished for more.

[jrevens]

I agree with Jim - good advice. FWIW, 6000 Oratex isn't really thinner than Poly-Fiber medium, but the end thickness of the Poly-Fiber can vary considerably depending on how much & what type of paint you use of course. There are only 2 layers of Oratex in that area on my rudder - well, 3 actually at the limits of left/right travel. I did mine beforehand, as well as setting the rudder stops, and, probably surprisingly, they ended up being OK.