High Mountain Doings

From 8200 feet along one side of the Upper Arkansas River Valley in central Colorado, my blog is about many things: travel including river and bicycle trips, and other experiences as well. The focus is on photography, not lots of text.

Saturday, January 23, 2010

Elevator Control Mechanism

Here is the recently-mounted elevator control mechanism at the top rear of the vertical fin. When the horizontal tail mounts here, the elevator fits into this white piece and is thereby controlled. This will allow the horizontal tail to be removed at will--a very convenient feature for some people.

Since I don't yet know exactly how I'll set the elevator (equal movement up and down, or something else) I am not going to use threadlocker on the connection where the twistum is, yet. I put the twistum there to remind myself of this. Note that the other nuts seen here have red paint on them and also (invisibly) had blue threadlocker applied. The red paint will allow me to instantly see if these have moved, come inspection time.

Monday, January 18, 2010

Rudder Cable Connection

Here are two photos of the actual swaging of the rudder pedal cables as they're connected to the bracket that will provide a base for the rudder.
The red paint marks the position of the cable against slippage as it doubles back around the horseshoe-shaped fitting and through a small piece of a rather soft metal.  This will soon be squeezed (swaged) into very tight contact with the two cable segments. It did slip, as cable wrapped around like this is likely to do. But recovery was easy with the marks I'd made. Once swaged, the two cable segments are fixed in position forevermore.

The bottom photo shows the actual swaging of the rudder cable into its loop, for connection to the left hand hole in the rudder mounting bracket, which can turn 30 degrees in either direction, also turning the rudder. These cables come from the rudder pedals in the cockpit. This is a swaging tool, where you put it over the metal to be squeezed, and tighten the bolts to deform the metal around the two cables.

Rudder Cable Attachment

This is a hard job that's continuing. That is, I didn't get it finished today. Mostly because it has to be right the first time, because a swaged cable isn't something that's easily changed.
The rudder cables connect to the ends of the bracket on which the rudder mounts. Pins in the rudder will fit through the two holes that are just inboard of the cables. Simultaneously, a fitting in the other (top) end of the rudder will slide down over the upper hingepin which was just mounted.

The thing here is, if there's too much slack in the cables, it appears that the rudder will work less well. In fact, if there's slack, the pedals will lean a bit farther forward though I want them to be 5 degrees aft of vertical. Too much of this, and the pedal would bottom out before it deflects the rudder fully! This can't be.

Get it right, and the pedals will turn the rudder without a lot of free play, and travel will be full.

Speaking of rudder deflection, I had to change the right hand rudder stop. This is one of the two hex screws seen here, with locking nuts on them. And blue threadlocker, to prevent problems.

I'm hoping I can get it all like I want it, marked, ready to be pulled out (I think it'll come out far enough, without me having to disconnect cables on their forward ends) to where I can swage it. That is, use my swaging tool to squeeze the bushings down around the cable for a good, solid connection.

Tightening the Nuts

I saw that I needed a wrench unlike any I had. So off to town, where I got a wrench on which the wrench-head could turn to slightly less than 90 degrees to the handle. I taped the head onto the handle, to make sure it wouldn't come off. I also got some cord, taped the end of that to the wrench handle, and tied the other end to the hole there where the stabilizer will mount. This was, of course, so I wouldn't drop the wrench and have it go clank, clank, clank way down inside the fin.

Thus, after applying red threadlocker, I was able to tighten those nuts while easily holding the bolts with a hex key.                                                                                                                                                                           

Upper Rudder Hinge mounting

When I mounted the upper rudder hingepost, I first epoxied it on and was soon going to drill the bolt holes and get it bolted on as soon as I could. I didn't do this soon enough the first time, and the hingepin assembly got bumped and knocked off. At least, I now had a smooth base of epoxy to mount it to!

The mounting with epoxy went very well, per the last photo here. I peeled off the Peel-Ply after a while, didn't do any more work that day, and on the next day I drilled the bolt holes.

Getting the nuts onto the ends of the bolts would be a tricky business. I'd Dremeled the access opening larger, as directed, but the space below was still not very accessible. It called for ingenuity.

I used a Twist-um to hold back the vertical pushrod. Then I had to put washers on the two bolt-ends. I put a piece of masking tape around my finger, and folded another piece to make it sticky on both sides. I stuck this onto the tape that was on my fingertip, and stuck the washer to the other side (double sided tape would also have worked). Then I reached into the opening, washer stuck to my finger, put the washer onto the bolt, and sort of brushed my finger away from it, leaving the washer on the bolt-end. Then I could put my finger back in (sans tape now) and slide the washer down to the base of the bolt, so it wouldn't fall off.

Then I taped the locknut lightly into a 10 mm open-end wrench and was able to get it started onto the bolt.  Snugged it up with the socket wrench that's in the next photo.

Sunday, January 17, 2010

Lower portion of the tool in use

The lower part of the hinge pin installation Bracket, and Paul Kuntz's alignment tool.

Thursday, January 07, 2010

Closer View of Hinge Pin Brackett

This is the upper rudder hinge pin being held by the jig. Once the jig is gone, it'll be ready for the two bolt holes to be drilled, and bolts installed. That won't be an easy job, as a later photo will show. The white dacron tape across the bottom of the bracket, held in place by some tape, is "peel-ply," which is for holding wet epoxy in place. When the latter is hard, the tape is easily peeled off. It worked really well. It didn't stick, even where it's saturated with epoxy.

Wednesday, January 06, 2010

Overall View

The big view of the Sinus, with the stabilizer temporarily mounted. No elevator or rudder yet. The pile of parts underneath the aircraft is considerably smaller than it was. The wings, of course, will not fit on until I get the fuselage finished and moved outside.

Rudder Mounting

These photos are of the installation of the upper rudder hinge pin, which gets epoxied, and also bolted, to the dark fiberglass surface at the rear of the vertical fin.The jig seen here fits into the same holes at the bottom as the rudder will, and holds the upper hinge pin in the proper location for bonding and bolting.

Paul Kuntz in Washington state, a fellow Sinus-builder, lent me his jig. This saved me a day or two, and a trip to the hardware store to buy material and parts. One of the parts I'm sure I would have had to search all over Denver for. That's the small, cylindrical part on top with the set screw attaching it to the actual hinge pin that's being mounted.

The bottom of the jig mounts to the bracket that the rudder will mount to. I created two depressions in the bottom of the rudder so that the heads of two bolts can fit there.

The bungee cords hold the top of the jig, and the rudder hinge pin, in place while the epoxy hardens. After that, the bolts are installed. The first time I did this, Patty and I were trying to get it disassembled and the hinge pin got knocked off. Next time, I was more careful to keep it in place, drilling holes and installing the bolts quickly.

Sunday, January 03, 2010

Horizontal Tail

Here is the horizontal tail on my bench, which I padded with the very convenient packing material that came wrapped around these parts.

The job here is to install the pins into the fittings that extend from the left hand piece (the elevator), and tighten the nuts on each. You can't scratch the other end of the pins because they need to fit smoothly into the brackets on the right-hand piece (the stabilizer).

The piece of plastic tubing on the nearest pin is there because I found that with the tubing in place, I could grasp the pin without scratching it. Then I could tighten the nut.

I also installed a bolt mechanism in the hole that goes through the stabilizer, top to bottom, lining up with the threaded receptacle in the top of the vertical fin. The mechanism will allow the bolt to be turned (to remove the stabilizer) if the metal part surrounding the bolt is depressed, with the rim of the socket wrench or by some other means. When that part is up, it prevents the bolt from turning. This is a safety mechanism that will allow removal if desired.