Saturday, July 25, 2015

#17 Rigging and Final Assembly

This post will be the last one for this project.  It was intended to cover the repair of an Easy Riser damaged in a training flight. Subsequent modifications to the Easy Riser is being covered in a seperate blog titled "Re-Thinking The Easy Riser" and can be found at
www.easyriser3.blogspot.com

RIGGING & FINAL ASSEMBLY
Ready for rigging now I've moved the right wing panels onto the frame I had bolted to the floor when I completed the pre-rigging from sheet #3.

As I put the struts in place, I recalled the problems I had noticed when learning to fly. I took great pains to patch all the tears and holes in the glider I inherited only to have the leading edge root strut bracket rivnut punch a hole right through the nice patch I had put over the previous hole. Here is a photo of that bracket “after” I drilled out the rivets, flipped it and re-installed the pop rivets.

It turns out that there is plenty of clearance now on both sides of this bracket and I get no contact with either the fabric or the gusset with the bracket in this orientation. The strut fit is not changed. If you don't do this, expect to see a nasty hole punched through the fabric by the rivnut end as shown below on Darrel's upper wing panel trailing edge which I had just patched prior to realizing what was causing it.

I found it far easier to do the tail swage first, fit the cable loop over the bracket bushing, snug up the main swage and then compress it. The plan sheet says to do the main swage first which I tried at first and right away switched to doing the tail first. Another thing I'd do different would be to thread on shrink tubing PRIOR to all swaging. When I got to the end and saw where the cable ends contact the fabric I found it necessary to tape over all the swaged cable ends. In the folded storage/transit position there was a fair amount of abrasion happening not to mention getting holes poked in my finger tips from the cable wire sticking out of the secondary swage during set-up & tear down.



In this shot I am setting the final tension on this flying wire using two vise grips held with my left hand while tightening the wire clamp with my right hand. Otherwise I'd have needed to find someone to help. This worked fine.

I made multiple trials to get the tension on all the cables just right and it took a fair amount of time to do a decent job of getting them all “just right”. My swage tool (I finally had to buy one) was a short handled Nicopress model 32 VC-VG which does both 3/32 and 1/16 swages. It required quite a bit of muscle for the 3/32 swages so I ended up cutting a pair of extension “handles” from 1 ½ inch PVC pipe. The other critical tool I was lucky enough to borrow from one of the EAA members was a Felco cable shears. This made all the cable cuts a piece of cake producing nice, clean ends.


No photos of my trials locating the control cable inside the tip of the lower wing panel. Located a hole based on how Darrel's cable was deforming the fabric and hot knifed it free-hand. Turned out fairly crappy. Should have taped a nice circle template and cut to that instead. Since this was a re-build, the bushing was already swaged onto the cable end so I had to make the hole big enough to fit the entire thing through the fabric. Rather than do an actual fabric patch (would require me to do a spot re-paint) I just used adhesive-backed sailboat Dacron patch tape which worked OK.
Next I rigged the rudder return spring exactly like I re-configured Darrel's where I removed the bungee approach specified in the UFM plans (a poor solution I felt) and installed a nutsert (that's what the guy at True Value Hardware called it).
The nutsert can be seen above laying on the wing to the right of the hole it will be installed into.


This shows the nutsert fully installed.  It is nearly flush with the tip tube surface.

I picked out a spring from the hardware store spring selection and attached it to the wing tip using two nylon washers and a small bolt.  I also picked out a steel pin, drilled it to accept a safety pin and used this as a quick connect to attach the rudder control cable during assembly.  I replaced these soon afterward with a stainless steel spring (sourced on-line through Grainger) and aluminum binding post pin (commonly available at hardware stores).



The next step was to rig the control cable which involved wrapping it around the twist grips per the plan so that the rudders come back to neutral when released.


I really liked the grip material Darrel had on his glider which was cloth handle bar tape for bicycles. I had a hard time getting anything close to long enough. The best I did was less than 10 ft so that's what I used. The underwrap was just electrical friction tape followed by the cable winding then covered by the bike tape and terminated with vinyl electrical tape on both ends.


Now I am nearly done. I got worried about the paint sticking to itself in the folded storage and transit position so I decided to wax every surface except the bottom of the lower panels using the Poly Fiber recommendation of a non-silicon based Carnuba wax which took me a good part of a day to do but I'm glad I did as you will hear about in a minute. So here's the completed glider ready to pack up and take it's second flight (recall the first one ended in disaster over 30 years ago...hence this project).

Here I am at the local test flight area the next day on the Oregon coast (Cape Kiwanda) in perfect conditions....low tide, dune to myself with a 9mph breeze right up the hill.

Although you cannot tell from this photo, the glider is sitting on a tarp I staked down in the sand so that the glider never touched the sand.  I just could not bring myself to allow that after putting all this effort into the build.
I weighed the finished glider just to have an idea how much over weight I was and it came out at 66 lbs which is about 16 lbs over. I can feel the difference just carrying the individual wing assemblies and knew I was going to have my hands full getting this thing up the dune. I was right, I made it up to about 2/3 of the way to the very top and just decided I'd be so wasted if I went any further that I'd be too exhausted to safely launch it. I was determined to not even allow it to touch the sand that when I got as far as I was going I basically took off in what felt like 10-11mph breeze. Launched fine, flew fine, rudder response was fine and the landing was easy. I could not even visualize making another climb up the dune so I packed it up and went home with a smile on my face. This makes 19 launches in an Easy Riser for me to date. I have not yet learned to reliably get my feet up onto the leading edge to assume the proper flying pilot position.  This is a critical skill in order to be in the air for any length of time and certainly at any significant altitude.  If you are interested in my experience learning to fly, please visit my other blog dedicated to the learning aspect of the Easy Riser at

easyriser2.blogspot.com

I hope this helps anyone out there in building an Easy Riser as that was my original intent.  Refinement of the rigging, designing a parachute pack mount, re-design of the internal rib layout are some of the things to be covered in a follow-on blog which you can find here:

easyriser3.blogspot.com


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