Category Archives: Center Section

Control Sticks & Smoke Oil Fill

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Time: 6 Hours

Today I worked on installing, at least temporarily, the pilot and passengers control stick grips. I purchased the grips from Tosten Manufacturing after looking at them at AirVenture 2015. First task was to come up with a rough height for the pilots control stick as the original part is too long. After coming up with the link I took the stick out of the aircraft and cut it with a hacksaw. With the stick cut I marked a spot at the lower section to drill a hole for the wires to exit.  

 To make it easier to fish the wires down through I put some shrink tube on the end of the wires   
   once I had the hole drilled in the bottom of the control stick I was able to slide the wires through and do some measurements to see how the grip fit. It took me several tries to get the length just perfect so that it cleared the bottom of the instrument panel and crossmember. 
    
 A nice feature of these grips is the collar that the grip slides into. This gets held in place with a drilled hole and cap head screw which also holds the grip into position. This collar also allow for the grip to be twisted and raise up around 3/8″ as required to get a perfect fit to your hand position. I drilled a 3/16″ hole 1/2″ from the top and inserted the screw and jam but to hold it for now.  

 I basically repeated these steps for the passenger grip with an addition to putting the pilot seat back in place which is the limiting factor to the height as you don’t want the grip to hit the back of the seat when pushed full forward.  

    
 The grips turned out awesome and I love the feel. The pilot grip has a trigger that will be the push to talk button. The left lower thumb button will be for smoke. The hat in the center is for trim and the toggle to the left for flaps and to the right will be for COM 1/2 switching. There is a pinky button below the trigger for autopilot touch steering. The passenger will just have trim and the push to talk. From there I moved to another modification that I’m follow my buddy on. The oil tank obviously needs to be filled with oil at some point. The first way is to reach in and pour oil in via a cap on the tank. The next and better way is to use an external full kit that I bought from smokingairplanes.com. It allow you to open a cap like a fuel cap and pour oil in and not mess with the possibility of making a mess inside you airplane. Glenn showed me a photo of a P-51 Mustang and their center fuel tank fill port on the left side just under the canopy.  

 So we are gonna put ours just like that! Glenn had a side canopy fiberglass skirt from his last project so I used it to mark the location that it will lie on the fuselage.  

 From there I made the mark for the location of the 2″ hole. Glenn helped me hold the skin on the drill press to make the cut with the fly cutter. I used the support ring to mark all six holes for the screws.  

   I drilled the center of the holes with a #40 drill bit followed by a #11 for the #10 screw.  

 After all six holes were drilled I screwed the fill cap into position.  

    
   I will eventually paint the cap red to give that P-51 look. I’m really done with the items in the back except for a couple of wiring harnesses and those will arrive on Monday. So I started cleaning up a few items that I had on hold. First was to trim the cabin heat cable to its final size. I wanted to drill the tee for the smoke tank system that goes through the firewall. This tee will direct oil to both exhaust pipes. I drilled the 9/16″ hole and put the tee in place.  
 With the fitting in place I could cut the cabin heat cable to the correct length so it doesn’t interfere with the tee or my rudder pedals.  

   One last item was to cut the fuel boost pump wired and crimp some ring terminals on the ends. I then screwed them to a two place terminal block. This will allow me to unscrew them in the future for easy replacement as needed.  
Thats where I called it a weekend and will get back at it tomorrow when my parts arrive. 

  

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COM Antanae Cables

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Time: 2 Hours

I started the the time in the shop priming and riveting the parts together that made up the transponder bracket and put it into position. I had received a package from Aircraft Spruce the other day which included several different parts including the ones I needed for the antennas. 

 The parts I would be using is RG – 400 cable (similar to cable tv wire but aircraft grade and has a braided center core vs a solid wire) and crimp in BNC connectors. I watched several videos, including SteinAir, on the process of making these cables. After feeling good about the process I went about making my first one. The BNC crimp ons have three parts, the connector, the crimp sleeve and the pin.  

 The goal is to remove two sections of the cable.  The first is down to the center wire so that you can crimp the pin on. The second is just down to the inner braided sheath for the ground.  

    
 I then grabbed my label printer and printed the cable identification on 3/8″ shrink tube. This is a cool device that allows me to print directly onto white shrink tube that had a 1:3 shrink ratio.  

 I also got to use my new coax head for the crimpers. I will only be using two of the slots for this job. First is the .068 for the little pin then the .213 for the sleeve.  

 I crimped the pin then slid the sleeve in place. The connector them slides on and under the braided wire. You push hard enough to feel a snap as the pins ridge catches on the connector. Slide the sleeve back to the connector and crimp.  Then check your crimp to check for a short between the pin and the shield.  

   I then figured out the final length needed for each cable and cut. I then put the cable in its place in the fuselage going through all of the snap bushings. I didn’t repeated the process of adding the connector on the final and as it’s now in place and not forgetting to put the label on this and before crimping.  I secured the cable alongside of the flexible conduit with zip ties and put the 90° adapter on the end that will connect to the actual antenna. I left plenty of cable in the back to connect to the radio’s when they get installed. 
    
    
 A new skill learned and feeling accomplished! 

Prepping for the Turtle Deck Riveting

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Time: 8 Hours

I started the tasks that I need to get finished up before I can or want to start riveting the aft top skin, turtle deck, on. The first thing up was to drill all the required holes for snap bushings for wire runs. I have two runs that head to the back, pitch trim and tail light.  

    
 In the 1″ holes in the gear towers I used rubber grommets I got from McMaster Carr this week. Once all the holes were drilled and either a grommet or snap bushing was in place I started routing the wires. First up was the tail light and its 3 conductor shielded wire. I started in the tail and ran my way forward going through the snap bushings as well as some well placed adele clamps along the way.  

    
    
 After I had the wire run up behind the panel I used some 1″x 1″ adhesive backed zip tie anchors from Home Depot to add some anchor points.  

    
 I also ran some flexible conduit along the left and right side along the bottom ribs so that after the floor gets riveted in place I can run wires later if needed.  

    
 With the conduit run and secured with zip ties I ran the pitch trim wire from the tail to the pack of the panel. I used 5 conductor shielded wire the SteinAir recommended.  

    
    
   I ran the remainder of that wire from the panel to the aileron trim servo tray as well. I then moved to the static port installation in the afte side skins. For the non-aviation readers these ports give a “static” air reading to compare to ram air as the aircraft is moving for airspeed or a sealed pressure in an altimeter to measure altitude. I’m using the SafeAir pitot-static line system. I came up with the locations on both sides and drilled the holes to 1/4″ with a step drill bit.  

   I placed one of the ports in place to check the clearance on the bulkhead rib.  
 The next process is to secure the ports to the side skins. You can rivet these but I decided to just use ProSeal to secure them as many other builders have done. So I broke out the ProSeal stuff and mixed some up and sealed the ports to the skins. I cut a piece of wood to act as a brace to hold them until they cute.  

    
   Next up was to tackle the 2 shelves that I want to house the avionics. The first one I started on was for the to ADAHRS units that will supply the instrument screens with the attitude references it needs. I started with some 3/4″ x 3/4″ angle to make two supports across the upper longeron. This is a perfect place as they are level with the longitudinal axis and that’s what the ADAHRS need.  

 I added some .032 sheet to the cross supports to make a shelf for the units to sit on.  

   I also made a bracket out of some angle to bolt a Tee for the static line to.  
   After the static ports cure I will run the lines to them and to the new shelf I built for later installation. Fun day in the Hangar! 

Final Fuselage Assembly Begins

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Time: 6 Hours

Today was the start of the rebuilding process. All the priming and paint has been finished and parts are ready to be riveted together. So to start I grabbed the lower forward longerons and slid them into place. They each get 4 AN3 bolts that tie them to the lower engine mounts and angles. They also get 2 screws that tie them to the lower gear tower weldaments.

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(null)With those in place and torqued to the right settings I put a little or he torque seal on the nut side. This will be a visual cue to see if the nut has loosened. After doing that I realized the the 4 bolts at the forward end will be permanently covered with the bottom skin and I won’t have access to check the torque seal. I clecko’d every other rivet hole of the lower longeron and started the riveting. I used some painters tape to minimize any scuff of the new paint as well.

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(null)Next up was the mid cabin braces that get riveted and bolted to the center section. There is also a nutplate that gets riveted here as well. The bolts are AN4’s which required me to open the holes to 1/4″. I started with a smaller drill bit and final sized with my 1/4″ reamer.

(null)The plans next have to work with the forward/aft outboard seat ribs. These ribs get riveted to the aft spar attach point which has a spacer between the two parts to make room for the aft spar of the wings. I first clecko’d the ribs to this bulkhead and place the bolt into positing. I then was able to rivet all the pieces together.

(null)With that task done I moved on to the forward outboard seat ribs to the floor. I slid the fuselage so that the edge hung over and gave me access to the floor rivet holes. Since I was going to be riveting from the bottom up I used scotch tape to hold the rivets in place.

(null)That went fairly fast and I didn’t have to drill out any rivets, surprisingly since I haven’t riveted for a while. I then grabbed all the parts for the mid side skins and all the armrest/bulkheads. I first riveted the lower gussets to the forward bulkhead bottoms.

(null)Then the aftarm rest and mid armrest get riveted to the forward and aft bulkheads.

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(null)Normally the forward arm rests would get riveted as well, but since I’m doing a custom armrests I don’t do them now. With both the left and right done I grab the skins and clecko’d the armrest structures to them. I used my back rivets to rivet the armrest structures to the skin except for the aft armrest which will get done later.

(null)I was real happy with how they turned out and only a couple minor scratches in the paint. Next up was to grab the outboard Cito rib angles, the center section exterior plate in the mid side skins and clecko them into position. With all those parts in position I grabbed a long upper longerons and slip them into position supporting the aft end with my stand.

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(null)I grabbed my pneumatic squeezer and riveted the five rivets at the top of the gear tower structure.

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(null)I was able to get a couple of the rivets the tie the upper longeron to the forward upper engine mount with my squeezer. The rest of the rivets in that section will need to be done with my rivet gun and bucking bar. Since it was getting late and I didn’t want to make a bunch of noise for my neighbors I decide to call it a night at that spot. Another good day in the Hangar and it’s fun to see the parts going back together for good!

Build it up, Tear it down

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Time: 6 Hours

As the title says, everything you do with this building process you first build the section with all the parts in place and do your fabrication and match drilling. When that’s done you get to tear it all down so that the holes you just match drilled can be deburred and dimpled(if necessary). But Before I got started on the tear down I had received a small package in the mail from Van’s containing 2 parts I had ordered. The first was the replacement gussets that I accidentally match drilled in the wrong place last week. The other was a replacement of the left arm rest where the rear seat throttle is. I had made the rectangular hole I cut a little bigger than it needed to be. Would the first one have worked ok, yes but it was bugging me a little. So when I ordered the gussets I added it to the order. Fast forward to today when I got it out of the USPS plastic envelope that Van’s used and this is what it got:

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IMG_4985.JPGThe aft end of the arm rest has been smashed down flattening out the 3 flanges a little. I could fix those but the flat part of the arm rest has a dent in it due to the smashing and that I couldn’t fix. So I called Van’s and sent them photos and all the info hoping they will send me another one soon. The gussets were fine and that’s where I started today. It was a quick hop to clean up the edges of the gussets and put a bevel on one edge to fit with the inside corner of the mid longeron. Then match drilled and they were done.

IMG_4986.JPGAfter that little detail was finished it was time to do the tear down. Not much to show in this process as I just worked backwards from assembly.

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IMG_4988.JPGThat took a an hour or so to tear everything down and I had a close call with the long tailcone skins as I had removed the forward most bulkhead early which gave the skins structure when I installed them. Without them there as I removed the last side clecko’s the 2 skins started to fall away from the main section of the fuselage. Basically they tried to curl outward at the aft end. Luckily they didn’t go to far and I was able to coral them before they creased themselves! Whew! I organized the parts from this year down and moved on. The next list of steps on several pages in the manual are simply countersinking the various holes that will accept the bottom skins and the side skins. I slid the main section of the fuselage to the back of my bench, with ballast in the front part, so the center section was hanging off so I had access to the two rows of holes that are on the forward and aft flanges of the center section wing attach points. I needed to counter sink those holes so they would accept the dimples of the mid fuselage bottom skin. After that I moved the fuselage back to the proper place on the workbench. I then started the fun process of countersinking all the parts I removed. The plans lay out the order and I just check each item off as I go. The items I got done today were the lower longeron, mid aux longeron and the gear tower box plates.

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IMG_4991.JPGNot a lot of cool photos today since it is just boring drilling. I use my cordless drill on its slow speed as it gives me better control of the countersinking. I’m glad I have 2 batteries for this as there are a lot of holes. Tomorrow I will get back at the drilling and keep forging on.