After finishing the rear spar you have one task to complete before moving on to the fuel tank attached brackets. The fuselage bottom skin overlaps the wing by a few inches. The usual eventually get combined together with screws after the wings are attached for the final time. The wings skins add the holes drilled in them already but the fuselage skin does not. What you were supposed to do is mark all the holes on the wing skin with lines before attaching the wings so that you have a reference point and distance in order to drill the skin on the fuselage. However they make a cool drill jig that my buddy Glenn had so I borrowed it and made quick work of these holes. This tool basically as one side with a nipple that will identify the hole on the wing skin and sandwiches the fuselage skin between the tool so that you can drill the skin and it will match up perfectly.
I know that’s not the best description hopefully the pictures will help describe it better. So now when I remove the wings I will dimple the fuselage skin and put nutplates in the wing skin. With that tool I was able to get all these holes done really quick. From there you move on to the fuel tank attach brackets. When I built the fuel tanks I had put a bracket on each forward inboard corner that would eventually mate up with the brackets I need to make. The plans call for these brackets to be made out of U channel aluminum.
So I took the dimensions and measurements and marked them on the two pieces of U channel.
After four hours of drilling, cutting, grinding, sanding and filing I had the two final pieces. This is where they will fit eventually.
As you can see that they don’t fit completely flush up against the fuselage, and flush against the tank bracket. Van’s says to hit them with the large hammer in a vice to bend them to get them to sit flush at both locations. That is an understatement! These things are thick and not easily bent. It took me an hour to bend and manipulate the right side to get it to fit flush against the fuselage and the tank bracket. From there you clamp the brackets together with it tight against the fuselage and drill from inside the fuselage through the bracket. This is not an easy task as it’s pretty tight inside the fuselage. I started with a 12″ #30 drillbit from inside and finished with the #12 drillbit in my angle drill from the outside. with the first hole drilled I put in AN 3–7 bolt in and tightened it down to hold it tight against the fuselage. I then drilled the second hole and repeated the steps to finish that bracket.
I moved on to the other side and finished it up a little quicker than the first as I had a little insight as to where to bend.
With both brackets secured to the fuselage I marked the brackets for the single AN4 bolt and drilled the hole.
So now all the wing attach points have been completed. This will no allow me to build and rig things like the aileron attachment, flap rigging and fuel line connections.
Once I had the wings initially attached I set out to make their final adjustments. Even though the wings are securely attached at the main spar they still have a little bit of play since the rear spar is not drilled yet. This allows you to make adjustments before drilling and finalize their position. There are three adjustments that need to be done. First is the sweep forward and aft with regards to the wing tip and fuselage. To measure this you run four plum bobs along the wings. Then you run a taught string along the floor so that all four of the plum bob’s a line on that string. You can make adjustments forward and aft to get them to line up. The plans allow for up to 1/2″ in the difference. My wings were wishing 1/8″ and I tweeted them a little to tighten them up a little more.
The second measurement is to make the wings square with the fuselage. To do this you make a measurement from the tip of the leading edge on the vertical stabilizer to the seam on the wing top skins at the wing tip. Again you get a 1/2″ play in the two sides and I had less then a 1/16″. The final and most critical measurement is the angle of incidence. Every wing has some angle of attack built in to it with reference to a level fuselage. Van’s tells you that with a level fuselage you can run a level from the leading edge of the main spar flange to the aft edge of the rear spar flange and there should be exactly 2 51/64″ space between the aft end of the level and the wing skin. The easiest Way to do this is to make a spacer that you can place at the aft and underneath the level. My buddy Glenn had saved his spacer from his first airplane so I borrowed it to make my adjustments.
With the spacer and my 4 foot level and my digital level I worked my way along each wing at several different points checking the measurement. I had to make some small adjustments on both sides to get them just perfect.
With all three of those adjustments perfect I clamped the rears are in place. I then took the day off and came back at it the next day and re-did each of the measurements to doublecheck and triple check that they were perfect. After confirming that all the measurements remain the same I prepared to drill the rear spar to do this I used my drill cup and a #30 drill bit. The drill cup made sure that I drilled square to the surface. From there I stepped up using two readers and two drill bits to get the final size of 5/16″.
Now the wings are all set in their final position, hopefully the plane will fly straight and won’t have a heavy wing. Now that I have the wing secured in its position I can start to work on all the extra wing attach chores like rigging the ailerons, flaps and other items.
So it’s SuperBowl Sunday and I don’t have a team in the battle this year or since 1985, thanks Bears! I had my usual breakfast with Glenn and headed to the shop to tidy up some wiring stuff. Really all I had planned to do was finish the four wires that came off the intercom wiring harness that I made yesterday. Three were for the Skyview system to give unmuted audio alerts through your headset for things like warnings. The fourth was for a dimming feature for the intercom panel so when the Skyview dims so do it. Once that was done I just set out to really clean my work space from all the wiring. During this process I decided to move the fuselage for the eventual addition of the wings. I needed to place it so that I had room to work all the way around but also didn’t get in Glenn’s way for his shop work. With those requirements I came up with the location and we swung the fuselage around.
As we are sitting and talking about the planes and future pancake fly-in’s Glenn says let’s put them on! I say heck yeah and grabbed the tools needed. Glenn had some temporary bolts that he ground the threads off so they wouldn’t damage the wing spars. My girl, Tricia, wanted to be here for the wing mating so I called her to come to the shop. While we waited for her I taped up the wiring at the wing root and removed the pitot and angle of attack tubes from the left wing so they wouldn’t be in the way. I also filed a chamfer on the spar doubler to allow the spar to slide in a little easier. I sprayed a little silicone spray on the mating surfaces to help as well. Once they arrived my son Chandler helped Glenn and I to lift the wings and carry them to the fuselage. Chandler helped me align the wing root and Glenn manned the wingtip to make the required adjustments to help the wing spar slide into place keeping the bottom skin in place as well as the rear spar. Once in place I inserted the four main bolts in place. We repeated the whole process for the opposite wing. That’s all it takes and you can stand on the wings! This is a huge milestone for me and I was grinning from ear to ear. Thanks to my girl for taking photos for me. The wings are not on permanently but now I can drill the rear spar, adjust the ailerons and flaps and make the lower alumina flap fairings along with other important tasks. I will also get to work with the fiberglass wing tips, a new skill to be learned for me. For now I’m going to continue grinning and watch the SuperBowl!
So there it is! What a big deal for me to mate these two parts that have such a big amount of time between build times. I finished the wings over a year ago and now they are finally in place. Lots of work to do but days like these really drive me to work hard to achieve the end goal.
This blog post is for several days of work since it is mostly about wiring. After the last post on the start of the VP-X power connectors I finished up the remaining two connectors with all their power wires. I started by cutting and crimping all the pins in place.
I was getting a good rhythm on prepping the wires and crimping before too long. The tool that they loan out works really well and I had the remaining plugs done pretty quick.
So that finished up the power connectors so I packaged up the crimper and ran it to the post office to ship back to Vertical Power, thanks Chad Jensen for the great customer service. After getting that done I moved on to the Dynon harnesses. I will have to build one for the autopilot panel, intercom and both com units. I started with the autopilot panel and orginized the wires, labeled, cut and crimped the d-sub pins on. I followed this up with inserting the pins into the housing and put the d-sub backshell in place. I repeated these steps for each of the com units and finished their harnesses.
I decided to skip the intercom for the moment and moved on to the ADSB and transponder. Both of these have a power wire, and ground wire and two data wires that are orange and purple. These data wires are what the system uses to transmit and receive data. The Skyview screens have a 37 pin harness which has 5 sets of data transfer wires. Each is a different color with a matching purple and orange stripe. So you pick a color or port and match the orange wire from the equipment like the transponder to the colored wire that has the orange stripe and repeat with the purple. I used port #1 for the VP-X so that it can communicate with the Skyview system giving all kinds of information like how tha battery is doing and other electrical draws. Port #2 was used for the transponder and port #3 for the ADSB. Since I’m having dual screen, a 10″ and a 7″ I have to split the wires from the items, transponder, ADSB etc., to both screens so that they both receive the information. I hung the two 37pin harnesses on the back wall of the avionics area so that the length of the wires would be at a good distance to make the harness reach the screens.
Since I started with port #1 I finished up the last d-sub connector for the VP-X which houses the data wires as well.
So on to the intercom, the worst one. So for the record I am not a avionics guy and have no training on this stuff, with that said this is the hardest harness for me to build and this is why. From reading all about avionics specifically the communications parts the biggest problem is for noises to come through your headset like buzzing or static. To prevent these noises you use shielded wire, or wires that are encased with a braided cover under the white tefzel coating. This braided shield is to prevent other electronics like servos or motors from introducing noise into the communication wires. Makes sense to me that having these shields is a good thing. Here is the second thing that you have to do to prevent that noise introduction, grounding. So this shield needs to be grounded or connected to the airframe so that electrical charges can be dissipated. The biggest cause of noises in the system come from ground looping. Something new to me but the idea is that if you ground each end of a wire run there is the possibility that there is a different charge on each end of the shielding and could create a bad situation. So you leave one end ungrounded and ground the opposite one. Dynon wants you to have the ground come into the intercom and then to the ground block. So here is the fun part, I have 8 shielded wire bundles that need to be grounded. On top of that there are 6 of the wires that are inside those eight bundles that need to be grounded too. So what I have is 8 shields, 6 internal wires, a wire that will go to the pin in the d-sub and a wire that will go to the ground block that need to be connected together. This basically brings all grounds to one point and prevents any chance of ground looping. With all this chaos I had to really plan out my attack on them and figure what I wanted to do.
Here is what the block view of the d-sub looks like from the manual. You can see my chicken scratch on it helping me to understand what I was doing.
I used solder sleeves, like I have in the past, to terminate the shielding. I used one wire to figure out the best length for the harness and cut the wire. I then measured back 3″ to and removed that covering, trimmed the shielding and connected the solder sleeve.
So now I had the 8 shields terminated and a lead off of them. My plans was to solder these together and fold them back over so that a single wire could be added going towards the d-sub and a single wire back to the ground block. I also needed to add the 6 internal wires to tie into this bundle. I zip tied the ends together to hold them in place so I could solder.
I didn’t think that my solder iron would heat up this large bundle so I used my small torch to heat the wires and solder them. I added the wire that will go to the d-sub pin, each time I added wires I used a strand of wire to wrap around the bundle to hold them in place and just soldered over it.
Now that I had all the shield wires, the ground wire and the pin wire soldered I needed to add the 6 wires from inside the shielded wires. These wires are directed towards the d-sub connector so they needed to be bent back to be able to connect to the soldered part, and I didn’t forget the heat shrink before soldering them.
So now I had all 23 wires completed with their pins installed and needed to insert them into the d-sub housing. Before doing that I slid a large piece of heat shrink over all the wires to finish them off when done.
I then spent some time straightening out the wires so they looked good and zip tied the harness and added the backshelll.
So that was a very tough harness to make and took a lot of thought and planning. I’m real happy with how it turned out and think that it will work just fine. I would say I’m probably 85% done with my wiring which makes me happy thinking that all I need to do is screw in the avionics and connect these harnesses and I will be good to go, keeping my fingers crossed as I say that. I few more items left for me to then I’m off to connecting the wings to the fuselage which is a really cool thought.
I recieved the loaner crimpers from Chad at Verticle Power this weekend. So I decided to start the work for the power connectors so that I could get them back to him as soon as possible. These crimpers have a slot for the pins to slide into to hold it into perfect position. Once in position there is a sliding do-hicky that come down from the top to limit the wire that’s being inserted from going in to far.
Here is what the pins look like out and inserted into the crimpers.
Here’s the wire stop do-hicky lowered. So with the basics down, Vertical Power has a pretty good instruction manual, I started with the J8 power connector. There are three connectors that use this type of pin, J8 (8 pins), J10 (10 pins) and J12 ( yep 12 pins). The process is fairly straight forward as long as you follow their instructions. After crimping the insertion is done by aligning a little tab on the back of the pin to a notch next to the hole you are inserting it in. This is different from the other Molex connectors I have done which don’t require alignment during insertion. I figured out a good final length that I wanted for the harness. One that made sure I could reach the VP-X as well as giving me plenty of slack to install and move things around. Keeping my fingers crossed that when the day comes to install the VP-X I will have measured correctly.
Once I had all 8 pins done I cleaned up all the wires and zip tied them to create a nice harness.
It definitely helps to clean up all the wires in this side of the space. Now off to the other two connectors.