Wing Tips

Time: 4 Hours

I worked for several hours today working on the wing tip hinge modification. I removed the top and bottom hinge on the left wing and countersunk the fiberglass filler strips. I also used the pneumatic squeezer to dimple all the holes in the top and bottom wing skin. With those tasks done I clecko’ed the hinge halves back into the wing skin and riveted them in place. 

After I had the left wing skin hinges done I grabbed the left wing tip to work on its hinge halves. The idea is to rivet theses just as I did with the wing side with some modifications. The first is that I would use soft rivets, still aluminum solid rivets just a softer version, so that I wouldn’t damage the fiberglass. The second would be to apply a layer of epoxy between the hinge and the inside surface of the wing tip. The third thing would be to drill 1/4″ holes between the river holes on the hinge flange. This would allow me to put a small amount of epoxy/cotton flox into the hole essentially creating a epoxy rivet in between the soft rivets. All this to mate an aluminum hinge to a fiberglass tip. Here’s how it looked after I was done. 

 I will let the left side cure overnight and start working on the right side tomorrow. 

Flap Sensor

Time: 4 Hours

One nice feature of the VP-X is the flap control. With a position sensor, a smal device the translates the actual position of the flaps into a digital signal, you can take advantage of several features. The first is exact control of the flap motor either up or down with a single switch movement. The second is intermediate flap steps. Once the sensor is set up you can define the value of the flaps full up and flaps full extended. With those two numbers you can use any value in between to have intermediate flap stops. First up is to instal a sensor, I’m using a Ray Allen POS-12 that I got from Aircraft Spruce. There are no plans for how to attach this sensor but a few builders have documented how they did their install. The sensor is just a small potentiometer that has a rod that slides in and out for a total travel of 1.2 inches. The idea is to attach this sensor to the side bulkhead below the flap motor. Then attach the rod end to the flap push tune so that when the rod moves up and down as the flaps do it would either extend or retract the sensor rod. I went to a local hobby shop to get a few parts, clevis’s and threaded rod, that I used to bridge the sensor to the adel clamp I put on the flap push tube. I mounted the sensor to a scrap piece of sheet and put in an approximate 30° bend in the top end to give the sensor a straight shot to the flap tube when I clamped it to the bulkhead. 

It ended up working really well after I made a few adjustments. The idea was to have the sensor rod extend almost completely and retract almost completely. Once I had that adjusted I drilled the bulkhead for a screw to attach it. I hooked up my laptop to the VP-X and brought up the flap settings. The sensor was showing up perfect and just indicates a number between 0-255. That’s the digital number of where the flaps are. The up position was showing 0 so I set the VP-X at 1 to allow the motor to shut off. The number with the flaps full down was 233 so I set that for the flaps full setting. So now when I click the flap switch down on my grip the flaps run to full down and then the motor stops. The same happens with a single click up which brings the flaps full up. The VP-X also allows for two intermediat flap stops. So with the flaps full up or 0° I used my digital level to zero out for 0°. I adjusted the flaps down till the level read 10° down and looked at the sensor number. I plugged that number into the first flap stop. I repeated this process for 20° down flaps for the second flap stop. So now the VP-X goes to 10° flaps with the first click down on the flap switch. Click it again and you get 20° and once more for full flaps down at 40°. One click up and the they retract fully. I will be able to use the sensor data to create a flap indication on the Dynon screen as well later down the road. Turned out to. E a cool feature of the VP-X for just a little extra work. 

VP-X and Communications

Time: 6 Hours

The other day I recieved a box of goodies from Aircraft Spruce that contained several items including the Vertical Power VP-X Pro, Dynon COM and Dynon Intercom. The VP-X is a solid state circuit breaker technology that allows for a lot of customization and control of your electrical system. The pro version is a two buss system for redundancy and safety. I went agead and bought these items so I could power up the plane to check my wiring. I got the COM and intercom so that I could check my intercom harness and the headset jack for squeals and interference. First up was to mount the VP-X and get it into position.  

   Once I got it’s perfect placement I removed it and the brackets it came with to drill four holes for the screws that I would use to attach it. I then returned the VP-X to the spot and clamped it into position so that I could match drill the holes.  
 The forward side of the box I used the shelf I built and screwed it directly to the VP-X instead of the supplied bracket. After all the holes were drilled I removed the front bracket and primed it as well as put in two nutplates.  

 To get power from the battery to the VP-C I needed to run a #4 cable from the battery contactor to the VP-X. I figured out the best run path and needed to drill a hole in a flange just aft of the battery compartment which was just above the battery contactor giving me a straight path to the lug I need to attach to. I had to remove the contactor to get access for the drill.  I also was drilling blind up through the flange and used a mirror to align the drill bit with a mark I made in the center of the flange. I then stepped up the hole size to a 1″ hole for a grommet that allow the cable and terminal to fit through. 

   I then made up the cable for the right length and attached the terminals. With it built I put it into two adel clamps to hold it into place and attached both ends to the VP-X and the contactor. Holding my breath I flipped on the battery master switch and watched as the VP-X lights came on! First test complete – pass. From there I grabbed my laptop I just bought off eBay, it’s a PC and I’m a MacBook guy, since the software is windows based. The VP-X comes with a crossover cable to allow you to transfer information from their configurator  application to the VP-X. The cool thing is the online planner that I designed my electrical system on the website creates a file you can use to upload to the VP-X. So that’s what I did and in a few seconds my system was loaded with all my switch inputs and all the avionics I loaded. So when I flipped the boost pumps switch on my pump actuall came on! Test two complete – pass! Now I grabbed my COM unit and intercom and screwed them into the panel for testing. The COM unit is just a head and has a box that I placed in the tail to conect the antanae and power harness up to. With all the harness’s and antanae connected I flipped the avionics switch on….they powered up!  Test three – pass! 

 The knobs and switches all worked and looked great. Now Glenn grabbed his headset and we plugged it in. Glenn turned on his handheld radio and I pulled the PTT switch and whoa it worked and worked very well! No squeals or static, at least not right now. So this proved that all my wiring for the intercom was a success and had no issues with all the grounds I had to deal with in that one harness. I tested both the pilot and passenger headset jacks and changed the com to both the number one spot and number two spot to check both sides wiring. The other thing I was able to test was the flap switch on the pilot grip. I found that I had the two wires backwards and the up went down and the down went up. That was an easy fix with the harness that went to the VP-X. One thing that I didn’t like was that the flap switch had to be held either up or down to make the flaps run continuously. In order to get the full benefits of the VP-X flap control you need to have a flap position sensor installed to allow the system to know where the flaps are at all times. So that’s the next install for me. 

Back to Work

Time: 8 Hours

The first task I started back at when I finally got back to my project was to work on the fiberglass wing tips. The plans call for these to be held on with screws so that you can remove them as needed in the future. Many pilot house different things in them like antanaes and remove compass heads to keep them from the main structure where they may get interference. The only thing I’m going to have in them is the landing/taxi/nav lights. One down side to using screws is that when you removed them post painting they always seem to crack and chip. This ends up being a eye sore if you have ever seen them repainted with touch up paint. Our Lears have the same issue and they look bad once you remove the screws for anything. One cure for this on the RV’s is to use piano hinge to attach the tips. This isn’t for the purpose of having anything hinge open or closed but for a hidden, clean hinge pin to hold the two parts together. There are many builder and many directions online for just this task. I have read several and discussed with my buddy Glenn on how he did his and came up with my plan. First up was to drill additional holes in the wing skin between the holes that were for the screws as you will need extra support for the hinge. Then I cut my hinges to length for the top and bottom of the tip.   

   I then drew a center line on each wing of the hinge so that I could align them with the row of holes I just drilled. I am using two different sizes of hinge combined together, -3 and -4. The reason is so that the hinge center is off center as you look at the seam between the tip and wing skin toward the wing tip. This ensures that the notches of the hinge are hidden and if there was any gap you would just see solid aluminum of the flange. It would also help prevent moisture from getting inside.   

 The tips have a flange that slides into the wing in the normal configuration. In the hinge method this is removed and used as a spacer between the skin and the hinge flange to keep everything even. So the next steps are pretty easy. First measure the space between the two lines drawn on the hinge flanges, one for the wing side and the other for the tip side. Transfer that measurement into the tip and mark the holes for the tip even with the wing side holes.  



 Second clamp the hinge in place so that the line you drew, on the wing side of the hinge, is lined up with the holes you drilled through the wing and tip.  

Then you match drill the holes from the tip to the wing side. After that you drill the tip and tip side of the flange at the same time using the marks you just made.  

   The flange on the left of the next photo will be cut off to use as the spacer. I will sand the edge up to the lip to create a tight seal between it and the wing skin.  
 After I had all the holes drilled I grabbed the Dremel and cut the flanges off. With those cuts I separated the hinges and clecko’ed them to their respective parts, using the removed flange as a spacer on the wing side.  

   Based on the advice of some builders I planned each of the hinges to have a eyelet start on the aft end of the wing side on both the top and bottom. The reasoning is that you can insert the hung pin just enough on that eyelet on the wings and have it just sitting there ready to go. Then when you grab the tip to attach it you can hold it in place with one hand and use the other to insert the already started pin making this a one person job.  
 I am real happy with how the left tip turned out and how the hinge looks. I will work on the hinge pin and how I deal with those later, now on to the right side tip. I just repeated the entire process on the right wing as I did on the left side. In the process where I split the hinge and clecko’ed the pieces to the wing skin and tip I realized I made an error on the top hinge. Somehow I got the hinge alignment off and it wasn’t squared up with the aft end of the top skin of the wing. A couple of options was to just cut the hinge overhang off and make it flush. The downside to that would be that there would be just about a 1/3 of an eyelet remaining on the wing side hinge. The other option was to just redo the top hinge, that’s what I did since I had a lot of extra hinge left over. This presented with a new challenge since I have already cut the fiberglass. What I did was thrilled that he inch to the wing skin first and clecko’ed into position.  Hi then attach the wingtip using the bottom hinge in it’s  hinge pin. I was then able to use the holes in the fiberglass top to match drill the hinge that was underneath.  Everything turned out very nice even though I had to go at this one a little backwards.  

  For now they are on, I still have a lot of work to finish this modification up. 

Life Update

For many of you, my blog readers, are family and friends and know my family’s recent tragedy. For the other readers I will explain my blog absense for the last month or so. On evening of March 7th my world as a father came crashing down with one single phone call. I had recieved this call from my ex-wife that our oldest son, Tanner 19, was in an ambulance on the way to the hospital. Through her tears all she could say was that they were doing CPR and she was scared. Where they live to the closest hospital is 35 min if driving fast as an ambulance would. I waited with my iPhone in my hand until they arrived at the hospital to receive word from her on my sons condition. That call came just a few minutes after they stopped CPR and pronunced the time of death at 11:54PM from a blood clot in his lungs.  My world changed with that one 30 second phone call, I couldn’t breathe or talk. The following days were a blur from the next day traveling to Iowa to make funeral arrangements to the end of the week when we finally got to say good bye and bury my son. The last few weeks have been very tough for me as a father and for the rest of the family. I have always found great peace in working on my RV-8 and the joy of building. I was having trouble just getting through a day let alone wanting to do something productive. As the days have gone by I have been able to get back to work and adjusting to a new normal. Thanks to great family and friends, especially Tricia, Thomas and Glenn, I have a great support system. This last weekend I had breakfast with Glenn and made it to the shop for a couple hours to get a little aluminum dust on my hands. It felt great to get my mind off of our tragedy and on to the project even for just a short time. He will always be with me in my heart as he will with all who he touched in his short life.