Practice frames completed

I finished welding up a couple of frames to practice fabric covering before we cover real plane parts.  The frames were made from electrical conduit, and welded up with the TIG machine.  The galvanized coating on this cheap conduit causes issues with TIG welding (sparking and sputtering), so we used a buffing wheel to remove the coating before welding them up.  Hours: 3.0

Two completed frames

Tool fabrication

I had previously made a special wrench when we were going to use a Sonex connector for the vent line in the wing tanks.  But then we later realized that this connector woudn't work so we changed to an alternate aluminum fitting.  Unfortunately, this alternate fitting was a different size, and required me to make a new special "thin" wrench that will allow us to install it easily.  But it wasn't too hard since I had practice. I traced the shape out on paper, transfered it to a sheet of steel, cut it out, and buffed it smooth.  The final part came out nice and fits the new connector well.  Hours: 2.0

Paper template and fabricated wrench

More Welding

We continued to work on our practice frames.  Ed welded up the first frame while Michael started working on the second practice frame.  Since these are practice frames we're using all available pieces of conduit.  Ed is going to have to weld two pieces together in order for us to get the needed pieces.  Hours: 1

Ed welding

Fabric Covering

Ed and I decided that we'd do some practice covering before starting the covering job on the actual airplane.  We decided to to build some 18" x 18" panels with curves.  We bought some 1/2" electrical conduit from the local home improvement store.  Using a conduit bender we bent two pieces of conduit.  Then the ends were cut at 45 degrees.  A supporting brace was cut to go down the middle and the ends of it were shaped to give a nice tight fit.  Ed tack welded all the joints using his TIG welder.  All the joints were completely welded on one side.

Practice Frame being welded

We started working on the second panel.  The design is going to be a little different but the same 18"x18".  Rather than the bends being on opposite sides, they'll be on adjacent corners.  The bends were made on one piece of conduit.  More work on be done later.  Hours: 1

Conduit bent to shape

Miscellaneous Work

Long time since posting to our Blog!  We've done quite a few things and spent four days at the Triple Tree Aerodrome Fly-in.  If you've never been to Triple Tree (SC00) you should make a point of going.  It's a 7000 foot grass runway that is perfectly manicured.  Ed and I pulled a camper and spent the days watching everything from a Citation Jet to a DC-3 to quite a few Just Aircraft arriving and departing.  We also attended a fabric covering workshop.  Although the process used was the Polyfiber process and we plan to use SuperFlite, it was very similar and we got a lot of good tips. Will definitely plan to go back again next year!

Mike at the covering workshop

Ed at the covering workshop

One the building front, the template created for the left side of the cockpit are was transferred to the aluminum piece that had already been fitted.  The hole for the aileron cable was passed through the opening and it was found that it needed to be made larger.  The problem with the paper template is that is flexed enough that it appeared to have enough opening, but once it was installed on the aluminum piece it really did not.  So a slight modification to the hole and now it fits perfectly.

Side aluminum piece (F-2120) with cable hole

We've also been working on getting the Roll autopilot worked out.  The roll autopilot will us a servo with capstan to move the control cables going to the aileron.  In order to connect the autopilot into the existing control cables we needed a way to join the autopilot cable and the aileron cables.  What we needed was "bridle cable clamp".  Doing a search online, I didn't find any that were easily purchased.  I did find some "used" clamps on eBay, but they didn't quite match what we wanted.  What they did do was give us some ideas on how to construct our own clamps.  The first prototype was made by drilling through two aluminum halves.  This we extremely difficult and the results were less than perfect.  The next parts were made on Mike's mini mill and these parts came out perfect.  We purchased a 1/16" ball nose end mill for the autopilot cable and a 3/32" ball nose end mill for the aileron control cable.  The key to getting them all aligned was to mill the slots on a 6" piece of aluminum and then once completed cut the parts to size (about 1-1/4" each).  The key to a tight fit was to mill the depth of the slot a little less than half of of 1/16" and 3/32".  When they two halves are mated and clamped together they hold the cables nice and tight.

At the top if the completed clamp, and the bottom shows the opened clamp.  Correct hardware will be used in the final installation.

And finally, we've also been working on a vent line from the header tank to the right main wing tank.  In order to get the flexible tubing to the feed point on the wing and allow the wing to fold, we are going to have to cut some of the root rib webbing.  To replace some of the strength, we are going to sister an aluminum plate to the area where the web was cut.  A tracing was made of the root rib and transferred to aluminum.  After some cutting, filing, drilling and dressing a nice part was made. 0.040" aluminum plate was used to make the part.  Total hours for this update: 12

Part ready to be installed

Aluminum web fits perfectly

Fuel vent lines

We ran into several issues with the original plan for a vent line to the wing tanks.  The engine (Rotax 912is) installation manual states that a 1/2 inch vent line should run from the header tank to the wing tanks.  We reviewed the plans of other builders who have installed a vent line, but it looks like the few other builders who used this engine installed 3/8 inch lines and not 1/2".  The larger diameter is a much larger challenge because the vent holes, fittings, and hoses all have to be larger, and the area we are working in is already tight.  But we now have a plan (well, actually we had multiple plans, but had to scrap them and rework our plan until we had something that will work).

We drilled a hole in the side of the fiberglass tank for the vent hole.  Originally we planned on using a fitting from Sonex, but had to scrap that because it required access from inside the tank, so instead settled on a more common alumninum fitting. We wanted to minimize any dust or debris that ended up in the tank during drilling, so prior to drilling, we attached a blower (actually a vacuum hooked up in reverse) to the fuel door on top of the wing to put positive pressure in the tank so most of the debris would blow out of the tank.  This worked great.  We started with a small 1/8 inch drill bit, then used a step drill to increase the size of the hole until it was slightly undersized for the fitting.  Next we actually used a large (3/4" NPT) tap to thread the fiberglass hole.  We don't expect it to seal well at the threads because there are so few threads, but it will help hold the fitting in place.  We will be using West Systems epoxy and flox for final installation to assure a leak-proof seal.

Hole drilled in fiberglass tank.  Blue fitting temporarily installed

A finger-strainer will be installed inside this fitting, and then a 1/2 inch elbow (on order) will be installed.  1/2 inch fuel hose (also on order) will attach to this elbow.  The fuel hose will run to the cockpit above the door, and will have enough slack to allow the wings to be folded (same as the fuel outlet hose).

Hours: 10

Aileron Cable Routing

Decided to make a paper template for the cockpit side pieces (F-2120) located on the outside of each seat.  A hole/slot needs to be located and cut where the aileron cable goes from the top side to the bottom side.  After quite a bit of experimenting the hole was located in the template.  We'll transfer this to the actual aluminum part later.  Hours: 1

Paper Template. 
You can see the orange temporary string going through slot

Fuel Feed

Finished the supply side of the fuel line from the header tank to the fuel cut off switch.  Installed some mounting adel clamps to make the fuel line more stable.  Finally the fuel like was cut to length, fuel fittings were installed and the end flared for connection to the fuel cut off switch.   Hours: 1

Fuel supply line to the cut off switch

Aileron Autopilot Servo

Had to make a slight adjustment to the aileron servo mount.  When I fitted the parts, I found that two moutning bolt heads for the servo interfered a bit with a bracket.  This was a bummer, and I contemplated drilling out all the rivets on the bracket to fix it.  But then I thought it might be easier to use Michael's mill and (very) carefully mill out a slot in part of the bracket to fix the interference.  This worked out pretty good, and I didn't have to remove any rivets.

Milling the right angle bracket to fix some interference

Notch in right angle bracket provides room for bolt

I spent some time aligning the position of the motor, and found that I needed to make some additional 1/4" alum. spacers to drop the servo down a little bit.  By doing this, the cable that runs to the pulleys (that are doubled up under the existing aileron pulleys) lines up nicely with the pulley on the capstan servo.

Servo with 1/4 inch spacers under the servo bracket

Next I mounted the whole shebang in the airplane, right under the control stick mixer.  I double checked alignment with some orange string just to make sure I didn't screw anything up.  Alignment looks great, and one of the next steps will be to get a cable made that will replace the string.  I'm attaching several pictures below of the installation as it is hard to see how it all fits together from just one angle.  Hours: 6

Autopilot Servo pic1

Autopilot Servo pic2

Autopilot Servo pic3

Autopilot servo pic4

Autopilot Servo pic5

Autopilot Servo pic6

Autopilot Servo pic7

Fuel Lines

The past few days, we've been running 3/8" aluminum fuel line from the header tank to the front of the fuselage.  The hardest part was finding points on the fuselage to install adel clamps for mounting.  The first line to be run was the fuel return line.  The fuel return line runs from the firewall directly to the header tank. The fuel line runs through a notch in the floor panel, turns 90 degrees and then runs down the middle of the fuselage.  

The next line to run was the fuel supply line.  The fuel supply line will run from the header tank to the fuel selector valve.  Like the return line, the supply line runs through the notch in the floor panel, turns 90 degrees and runs down the middle of the fuselage.  The supply run still needs it's installation completed.  Hours: 3

Header Tank with Fuel Lines

Fuel Lines with Adel Clamps for mounting

Fuel Line heading toward the firewall

Front autopilot servo, Header tank drain

I continued work on the mount for the autopilot servo that will control the ailerons.  A right angle stiffening bracket was riveted to the mounting plate that mounts under the control stick mixer.  There are two gaps in the rivet line to avoid interference with a secondary mounting bracket that holds the servo.  I actually had to make the bracket twice because I screwed up the first one by not making the bracket wide enough.. and the rivets would have been too close to the edge.  But nothing wrong with a little extra practice.  The second stiffening bracket came out just fine.

Stiffening bracket riveted to mounting plate

I temporarily installed the mount, and also clamped on the servo bracket temporarily to figure out the alignment.  Once more I broke out the orange string to precisely determine the best spot to place the servo.  I found that I needed to drop the servo down just a bit more, so added some spacers between the servo bracket and the base plate to until I got the string to align within a degree or two of all the pulleys.

Servo temporarily clamped to the bottom of the mounting plate

On Friday Ed and Michael located and drilled the mounting holes for the fuel selector valve plate.  On Saturday, Michael installed the fuel selector valve on the fuel selector plate.  This involved drilling a large hole in the plate and locating the mounting screw holes.  Since we wanted to have the valve removable, nutplates were installed on the fuel selector plate to accept the mounting screws.  We realize that the valve needed to be rotated 180 degrees so that the PILOT could read the markings.  So a new fuel selector plate was made from 0.040" aluminum plate using the original as a template.  The second one was completed much quicker.


Mike also installed a flexible connection from header tank to sump valve.  6AN fittings were installed into the header tank and the sump valve.  Stainless steel braided fuel line was added between the header tank and sump valve.  We went with a flexible hose here because of the short distance and vibrations during flight.  On each end of the SS braided fuel line a 6AN fitting was installed.

Fuel Selector Plate Drilled and Cleco'd

Fuel Selector Valve Installed in the Correct Orientation

Hours: 6

Front autopilot servo mount

Construction began on a mount for the autopilot servo that will control the ailerons.  A 3 5/8 x 10 1/2 inch aluminum plate was cut from a sheet, deburred, and four holes were precisely measured and drilled so that they match up with the mounting holes for the control stick mixer.  This plate will mount under the control stick mixer.   Hours: 1.5

Al plate for the autopilot mount (viewed from the bottom)

The new parts arrived from Aircraft Spruce and a new push rod on the pitch aileron servo needed to be made.  The part was clamped and the solid aluminum rod was centered drilled.  One side was drilled so it could be tapped for a 1/4-28 and the other side so it can be tapped for 10-32.  The correct rod ends were installed on each end.  The push rod was then installed between the pitch servo and the elevator bellcrank.  Hours: 1.5 ( Additional Time)

Center drilling the Pitch Servo push rod in Drill Press

Pitch Servo Mounting

After finishing the pitch servo mount yesterday, today's task was to get it installed on the mounting plate that was previously installed.  Due to the space required for the servo mount, it was found that some rivets for stiffening bracket were going to interfere.  Two rivets were drilled out.  The holes from the removed rivets line up with the mounting holes in the servo mounting bracket.  After positioning the servo and mount to the needed location it was clamped in place.  The four mounting hole locations were drilled for AN3 hardware.  Once drilled it was disassembled, deburred and then re-assembled with the correct AN3 bolts/washers/nuts.  Hours: 1.5

Pitch servo in it's final location

Pitch Autopilot Servo Mount

We had one servo mount from a previous project, but we needed two!  So, using the existing mount as a baseline, Michael created a paper template.  He then transferred it to 0.040" Aluminum sheet.  The part was cut out and filed to final shape.  The angles were bent on a brake and finally the holes were drilled.  The Garmin autopilot servo was mounted in the bracket using AN hardware.  Hours: 1.5

Original autopilot servo bracket

Paper Template created

Garmin servo mounted in new bracket

Autopilot and Fuel vent update

We did some more planning and prep for installation of the autopilot servos.  We plan on tying into the bell-crank (for the push-pull tube) to control the elevator.  Below is a picture of Michael who is working on installation of the mounting plate for the servo.

Michael with one of the autopilot servos

We also did more planning for installation of the autopilot servo that will control of the ailerons.  We had heard that other builders had mixed success with autopilot control of the ailerons... but we already had purchased the servo, so we figured we might as well install it and see how well it works for us. The method of installation we plan on using is based on another builder who put the info out on the Wings Forum.  We will add a second pulley underneath the front two aileron pulleys, and run a secondary cable to a capstan servo to control the ailerons. We are currently still in the planning phase, but I put together a quick mock-up, running orange string instead of cable to make sure everything worked and all the clearances are good.  Below is a picture with everything clamped loosely in place... but it looks good so now we will have to build the mount and make it all work.  Actually have to buy some more aluminum to make the mount.

Servo temporarily clamped in place; Orange string used to check clearances

Also ran into a bit of a setback with the installation of a fitting for the vent line.  The fitting we purchased WOULD have worked great... except it requires access from the inside of the tank.  But I forgot to account for the fact that there are 3 permanent baffles in the tank, so there's no way of getting to the inside edge of the tank (where the vent will be) from the top fuel cap access hole.  So now onto plan B.  We plan on screwing in and epoxying a fitting from the outside.  A new fitting was ordered, and that will be installed in the not too distant future.

Hours: 4.0