Wednesday, January 31, 2018

Section: 11
Hours: 4

Today I set the hard stops for the elevators. I used the digital level app on my iPhone and measured the max elevator up movement and it came out to 26 degrees. The manual calls out 30. To add more you have to file away the stop at the back of the fuselage.
 I used a variety of files and the dremel to grind away the stop limits.
Here is the final result for 30 degrees of up. Both control arms are in solid contact with the stop at 30 degrees of up elevator.
 I only had to file a little to get the required 25 degrees of down throw. However, it was much more difficult to file the inside stop due to the tight space.

Tuesday, January 30, 2018

Section: 11
Hours: 6

Frustrating day. I worked on aligning the rudder and setting the throw limits. When the rudder is at full throw and hitting the stops, it is supposed to clear the elevator by .75". The manual says you can file down the rudder stops if you don't have enough throw, but isn't very helpful about what to do if you have too much throw. My initial setup had the rudder clearing the elevator by 1/8" or less. I adjusted the rod ends multiple times to improve the clearance. Each adjustment required removing the rudder to get access to the rod ends. Initially I thought I had to move the rod ends out to make more clearance but it kept getting worse. I finally discovered I could limit the throw by moving the rudder closer to the v-stab. Not intuitive, but after looking at the geometry it made sense.

Here is the rudder horn against the stop on the fuselage after adjusting the rod ends in a couple turns. No filing was required.
 3/4"+ clearance between rudder at the stops and the elevator.

Monday, January 29, 2018

Section: 11
Hours: 5

There are 2 nut plates at the back of the fuselage that interfere with the vertical stab spar. The manual specified that they be installed before chapter 11, but I decided to remove them for the following steps. I'll have to check with Van's to see what to do about the interference problem.

I drilled holes and installed the horizontal stabilizer and the v-stab forward mounting plate.

Next step was to install the rod end bearings for the rudder hinges. The drawing in the manual shows dimensions for how to set each of the 3 rod ends, but the dimensions are specified to the middle of the hole in the rod end. How do you accurately measure to the air in the middle of the rod end? I decided to compute and measure the distance to the flat on the head of a bolt inserted in the rod end. This worked, but it too is problematic in that you have to get the bolt parallel to the edge of the rudder and also rotate the bolt head to so the flat is parallel to the back surface.

I set the rod ends to the specified distances and hung the assembly on the tail. Beginning to look like an airplane instead of a canoe!!!

Sunday, January 28, 2018

Section: 11
Hours: 5

I continued work on chapter 11. It was really difficult to space the bolt between the elevators with the required washers. First of all it took me awhile to find the washers because they were hidden under the bottom flap of the bag they came in. Then I tried to insert the washers by hand with no luck. I finally made a 2 layer insertion tool that holds both washers.

I was able to wedge the arms apart just enough to slide the insertion tool with washers in and then slide the bolt into place.

Next I made a drill guide block and clamped it in place after carefully aligning both elevators in trail and triple checking the alignment of the trailing edges.
The manual allows that there can be some misalignment between the control arms as long as both elevators are in trail position. Mine came out pretty close compared to some I've seen.

Saturday, January 27, 2018

Section: 11
Hours: 5

I'm getting really good at mounting and un-mounting the elevators. The manual specifies a starting position for rod end hinges. The trick is to adjust them until you can move the elevator through the whole range of movement specified without the leading edge rubbing on the horizontal stab. I tried some massaging of the leading edges to get a closer fit, but in the end I ended up twisting out the rod ends a couple of turns.
Here I've clamped the elevator in trail position prior to drilling the center hole.

Monday, January 22, 2018

Section: 9
Hours: 4

Today I formed and closed out the leading edge of the elevator. Forming the leading edge is not one of my favorite tasks. Here's the process:

1) Carefully layout 100mph duct tape on the leading edge.

2) Carefully align PVC pipe to tape making sure to attach the sheet metal edge tangent to pipe. Carefully smooth tape onto pipe- no wrinkles allowed or do over. Woody made me redo the tape twice. He's a tough inspector but someone has to ensure quality...
 3) Clamp the pipe to work table. I used some wood blocks with holes, others have used metal j-hooks. Plastic sheet under the elevator lets it slide smoothly. Large handle at end of pipe allows sufficient leverage. Carefully wrap the metal around the pipe. Make sure you wind in far enough to get a full radius- don't stop short.
4) Some hand shaping is required to get correct overlap. You want the inner (lower flap) to not leave a gap when overlapped by the top flap. You may have to relax the curve on the lower flap so when it is tucked under it rests flat at the joint with the upper flap.
5) Rivet starting at the middle of each section and rivet every other hole working towards the edges. Make sure no gaps develop between the flaps. I prefer using the pneumatic puller because it is more consistent than the hand puller and it easier to apply the right pressure to keep the rivet seated while pulling.

Sunday, January 21, 2018

Section: 9
Hours: 3

I had put off attaching pins to the elevator trim servo because I didn't have crimpers. I took an EAA SportAir class on electrical wiring last March and learned how to crimp and what crimpers to get. I ordered a set from SteinAir.
I found the small molex pins were very difficult to crimp properly. They are difficult to handle or see, and it is hard to get wire, pin and crimper all aligned to make a good joint.
After much trial and tribulation I got all the pins attached and shoved into the molex connector, but I'm not real happy with the result. This is a flight critical component- failure in this connector could result in un-commanded elevator trim. I think I will cut out this connector and replace it with d-sub pins in shrink wrap per SteinAir's recommendation- 008:SIMPLE CONNECTION FOR AIRCRAFT TRIM WIRES

Saturday, January 20, 2018

Section: Avionics
Hours: 5

Before I assembled the position lights, I made a copy of the backs of the boards so I would have a guide for trimming the wing tips to clear the heat sinks. I cut out the paper and transferred it to the wing tips and then used a drill, dremel saw, files and sand paper to remove fiberglass.

Thursday, January 18, 2018

Section: Avionics
Hours: 6

I trimmed and fitted the 2nd wing tip lens today. I was more aggressive in trimming after figuring out the process yesterday and the job went much faster today.

I spent the rest of the day inside the warm house soldering. The LED packages are surface mounted and require some attention to detail to orient correctly for polarity. The + / - markings are hard to see on the smaller colored LEDs. These are surface mount devices and the large white LEDs required a little more heat to get the solder to flow properly under the tabs.
 Large resisters are mounted on the other side of the board.
Make sure to leave an air gap below the resisters to help with cooling.

Power transistors are surface mounted to the back of the control board.
 The front of the board has a variety of devices, some with fine pitch leads that require a steady hand.
Assembled boards with heat sinks attached with thermal tape. 
The instructions specify that you test the circuits using a small 9 volt battery. The control board has 3 colored LEDs that simulate the 3 positions so you can run diagnostics and try out the various blinking patterns. All the boards worked perfectly first try. Don't look directly at the LEDs when you apply power- you'll be seeing spots for an hour afterwards. I imagine that these will be very bright on ship power. I'll have to remember to turn them off before doing any formation flying...

Wednesday, January 17, 2018

Section: Avionics
Hours: 5

Some time ago I purchased a position/strobe light kit from FlyLEDs I had priced out other position lights and was disappointed about how expensive they are. I heard about FlyLEDs and thought it would be fun to build my own lights. I have soldered together quite a few projects over the years so I was confident I could build it. The company is based in Melbourne, Australia but the kit arrived surprisingly quickly after I ordered it and then sat on my desk for a year before I got to it :-(

I ordered the wing position lights and the tail light as well as the heat sinks (it gets hot in the CA Central valley during the summer). The kit includes all parts, solder, thermal paste and nicely detailed assembly instructions.
The first step in assembly is to trim the circuit boards to fit in the wing tips. I started fitting the circuit board and realized I first needed to fit the plexiglass lens cover to determine how much margin to leave.

The plexiglass lens covers are oversized and must be cut down to fit. Make sure you get an optimal fit of the curves of the plexiglass to the wing and then trim off a little at a time and refit before trimming more. I used the bandsaw with a 1/8" blade to do the first 2 rounds of trimming and then used the belt and disc sander to do the rest. I used a single edge razor blade to scrape and chamfer the edges when I got to the final fit.

Monday, January 15, 2018

Section: 9
Hours: 3

Time to finish up some tasks that I had previously put aside. I've been working on the control system and now I needed to hang the elevators. I discovered that screwing in the rod ends for the elevator hinge system was a little difficult using standard tools. After searching Vans Air Force, I discovered a nifty tool made from PVC pipe. I turned down the end of a 3/4" pipe on the belt sander to let a small piece slip over the end. Then I cut a slot wide enough to fit the rod end. The slip on piece prevents the slots from expanding or breaking. Works great!

On page 9-18, figure 2 marks out 6 rivets as "do not rivet yet" which I followed. Somehow I missed the step where these rivets were supposed to be installed and ended up closing the skin to the point where I could no longer reach this area with the bucking bar. I contacted Vans support and they said it was ok to use pull rivets. I didn't have enough MK319-BS on hand so I ordered more from Aircraft Spruce. They arrived today and I installed them. Luckily these are on the bottom surface so they won't be easily noticeable ;-)

Friday, January 12, 2018

Section: 36
Hours: 3

I fit and installed the prewired control sticks from Vans today. First I filed off the excess powder coat paint and cleared the bolt holes.
 I used this tool to hold the washers in place while I inserted the bolts.
 I had to do a little filing to get the control stops to the specified angles, but luckily my stops as fabricated were very close.

Section: 54
Hours: 2

I purchased the flap position sensor kit from Vans. The Ray Allen sensor connects to the flap controller with a piano wire pushrod.
Unfortunately a hole has to be drilled in the flap crank for one end of the pushrod. The location of the hole is not reachable with a drill. The instructions recommend that you remove the flap crank, which would be a major job considering how hard it is to reach the bolts that hold it in place. I was able to use the 90 degree drill adapter to drill the hole. This is job that would have been much easier if it had been done back in chapter 34.

Tuesday, January 9, 2018

Section: 38
Hours: 4

I heated up the garage 70 degrees with the propane heater and drilled and counter sank holes in the rear canopy.
 There is a hole at the top center of the tail cone that must be dimpled. The top canopy brace makes for a tight fit for the squeezer, and I had to force the skin into the jaws. The dimple turned out fine and the skin bounced back to proper shape. I would have been easier to dimple this before installing the brace- just saying...