Seat Belt fun

Thanks Mike and Alan for comments about the seat belt. This is very valuable experience for you guys to share. In light of your feedback, I'm going to make sure to change or at least seriously evaluate how easily the belt opens before any flying. I can find a replacement lap belt with the push button type buckle with the same steel end plates, so I figure installing this belt won't be a backward step.

The original location Sandlin used was to loop the webbing material aft of the rear seat tube, just forward of the structural wing cable/strut attach point. Since I'm using the steel plate style with a 5/16" bolt, this location doesn't work exactly. The belt would rub on the end of the lower seat tube. My option is to move the belt to frame attach point forward.

Trying to figure out where to mount the lap belt, I have turned to aircraft standards, which are less descriptive for this mounting location than I hoped. From my student club days, I know the Formula SAE car competitions have stringent requirements on the students' creations, so I consulted the 2009 rules: http://www.sae.org/students/mbrules.pdf. Section 33.3 covers lap belt and in particular Figure 9 (shown here).

The Formula SAE regulations give a minimum of 45deg to a maximum of 65deg for the lap belt centerline to body angle. I clamped my belt in my proposed location and took a side-on self-portrait to compare the angle. I'm relatively happy with this angle, maybe even fine sliding the bolt forward a bit, and figure my updated seat will put my behind in a similar location for the belt angle. I'll probably sit on this (pun intended!) for a few days and pull out my 5/16" drill bit.

Some stainless hardware

No, not knives ... stainless steel clips, buckles, and coolness!

Berkley Point has the cutest little micro spring-clips that will do great keeping the horizontal tail secured. The extra spring-gate clip is actually going to be for the seat belt. The thimbles I purchased simply to have some on hand. And the "web threading plates" are for the shoulder harness of the seat belt, for 1" webbing.

The Aircraft Spruce order arrives tomorrow afternoon. What perfect timing for the weekend :-)

4th of July order

Okay, I bit the bullet and ordered all the remaining hardware for the wing & miscellaneous areas. It's a hodge-podge of bolts, some tubes that Dillburg didn't carry, and a seat-belt in there for good measure. On the seat belt, I'm going with a Style 2A and think I'll use the steel end-plates and 5/16" bolts through the frame instead of simply using rope. I'm pretty sure all the other tubes would be bent before the tied version of the seat belt broke, but I feel more secure with a massive bolt.

Steady progress

I did a bunch of work last weekend and figured I'd share. The control line came in sometime I think two weeks ago. In the same order from West Marine, I picked up two RF1853 Wide-D shackles. I was worried because they are 1/16" too narrow, but other folks seem to have them listed in their parts lists. After drilling out the threaded end to a 1/4" thru-hole, I had the anticipated problem fitting the shackle over the cabane end. These little parts are rather stiff too, being hard to force open a bit to slip over the ends; I tried to permanently deform the part, which might have helped a little. Anyway, they're on now and I'm sure a bit of tweaking will help the fit over time.

The major win last weekend was some time spent with a home-brew bending jig made from scrap 2" tubing and piece of MDF. I finally bent the elevator 3/8" x 0.035" trailing edge tubing and the other matching half. I'm pretty sure I've had this tubing since the very first order, so it's almost funny how long it has taken for me to get to this point. Now that I have the trailing edge on though, it makes the tail so much cooler ... when I move the elevator stick, something actually moves back there!

I am debating with the right inner trailing edge to hinge tube connection whether to use the fiberglass attachment method or borrow an idea I saw on another Goat construction site to make a more typical gusset plate type attachment. Right now I'm leaning toward the more rigid, but heavier, method. I've flown enough RC planes with similar torque rod arrangements for the opposite elevator half to know that a symmetric elevator is really nice to have.

As part of the elevator work, I was on a roll and also pulled out some foam and a new X-Acto blade to cut the ribs. Because these have a taper to them, they have to be cut individually instead of the all-at-once method I was able to use on the horizontal tail ribs.

Just last night during a really bad movie on TV, I made the slit to install the carbon rod spar caps. Unfortunately, I have now finished my carbon rod stock and was two ribs short. Fortunately, I recently came across a cheap site for more carbon rods (http://www.goodwinds.com). I need to get some 0.020" rod for hand-launch glider pushrods anyway, so it's convenient timing.

I also re-made the two right angle brackets that hold on the tail struts to the vertical tail. One of the previous ones I accidentally ovalized when drilling the 3/16" hole. This time I also took more time to make sure the strut can rotate around freely without binding. Yay.

In forward thinking news, I struck a deal for the timing of purchasing tubing for the wings. Aircraft Spruce was really expensive and would destroy me for shipping 12' tubes, so I'm going with a less-advertised company that is only 2hrs of driving time away: Dillsburg Aero Works in Pennsylvania. Their price was much better and I can go pick up the tubes in person to save on shipping. Look for a huge aluminum order around mid-August :-)

First time assembly :-)

Thanks to Matt for coming over and helping move Goat outside for the first time ... nice to get some grass underneath the wheel!

It was a neat test on the assembly procedure too. It's a pretty quick assembly, maybe 5 minutes for what you see put together. I imagine adding the wings and associated cables would double the time, but even that isn't too bad. It'll take more time driving than it will to get through the fun assembly time.

It's a little bit rickety right now without the cable bracing. The rudder makes the tail rack a bit, even with the stretchy line. I'm looking forward to having the real low-stretch control line. The wings and cables will be nice too of course, heh.

Oh yeah, the neighbor kids of course found us. They were a bit rough on the rudder. Sonya sure is cute not reaching the pedals though!

The only casualty is two $0.18 bolts that fell in the grass, DOH.

Wheee!

Cooking with gas again!

I was never really satisfied with 25deg rudder for only 1" rudder pedal deflection, so I started the morning by making a longer rudder control arm. I lengthened the part by 1" each side and now the pedals feel much better.

I also ordered 1/8" AmSteel-Blue 12-strand rope (very-low stretch) for the rigging. At only $0.43/ft, it wasn't too hard of a choice to use the "free shipping" that West-Marine has going on this weekend. I did a LOT of research yesterday to move away from the Lightning Rope. The AmSteel-Blue looks to be the updated version of Lightning Rope. It has a similar low-stretch: less than 1% elongation at 30% of breaking strength (2500 lb). Sandlin spec'd 7/64", so since I'm deviating I thought it was prudent to go the next size up to 1/8", which costs only two-tenths of a pound per 100ft of rope and gives almost 1000lb extra breaking strength. I'll consider this well-purchased insurance and eat the nose weight.

Speaking of control rigging, I finally used some of that Berkley Point hardware to connect the lines in a similar fashion to how it's supposed to work. Previously I had been simply tying new knots every time I assembled the plane. Now, I can get used to connecting the quick links to the snap hooks and start making a mental procedure to keep from connecting them incorrectly. I haven't set these up for the right lengths yet, so don't stress. I did install four new line guides on the bottom of the main fuselage carry-through tube. Coolbeans.

Last, I installed the tail strut end brackets on ~Thursday evening. They sure make quick assembly of the horizontal stabilizer onto the vertical tail. It's super nice to have the horizontal structurally held in place rather than with the stupid string I was using.

Feels like it's all coming together. 'bout time to get material for and start on the wings and feel under-whelmed again, heh ;-)

A whole evening for two parts

Does anyone have a better way to cut square holes?

I made the upper two ends for the horizontal tail support struts tonight. They are supposed to fit over an AN-42B eye bolt on either side. Sandlin has the builder to cut a row of holes and file down in-between to make a slot. I have a set of pin files that I've practically worn smooth now... whew, a few hours ticked away, but I'm done with the two strut ends.