Tuesday, April 30, 2013

Right Landing Light Instillation Completed

The idea of trying to get an early start in the shop to mount the right landing light came to a grinding halt within minutes. Van’s does not use the bolt that is shipped with the landing light because it is an Allen bolt and there is just no room to get hands on an Allen wrench through the landing light's opening. In place of the bolt shipped with the landing light, Van’s has the builder use a AN3-3A bolt because there is only barely enough room to get a box end wrench onto the bolt.

While searching for the hardware to mount the light, it was discovered there were no AN3-3A bolts in the shop. Early in the project, an order was placed to Aircraft Spruce for a small assortment of bolts, nuts, washers, ect. just to have on hand. It was thought that AN3-3A bolts were in that stock, so bolts were not ordered with the additional landing light hardware. Surprise!! Unfortunately, the shortest bolt purchased was an AN3-4A.

Because the EAA technical councilors will be performing the pre-closeout inspection on the right wing Thursday, wanted to have the landing light fully installed. Unfortunately, aircraft hardware is not something you can find at the local hardware store (if you can find one) or big box home improvement store … so the search was on to find the hardware locally because there was just not enough time to order from the normal sources.  After chastising the DOG Aviation purchasing department for the oversight, a computer search began followed by numerous phone calls.  As luck would have it, probably the nation’s single largest supplier of AN aircraft bolts (and so much more) was literally in my back yard!

Airfasco was contacted and they were gracious enough to let me purchase the necessary hardware plus a few spares to add to stock. While at Airfasco, it was discovered Aircraft Spruce distributes their products ... and hearing Van’s Aircraft purchases from Airfasco as well, brought a smile to my face.

With AN3-3A bolts in hand, the instillation of the right wing’s landing light was completed without any problems. First the tops of both landing light ribs were riveted, then the bottom holes were riveted, followed by the mounting of the landing light.
Riveting the landing light ribs in place prior to installing the landing light.
Landing light installed - note how tight it is to get to the mounting bolts.
Installed right wing landing light viewed from behind ... note the shims on top of the ribs.
Even thought the wing can’t be closed out until Thursday, there are a few things that can still be worked on in the meantime. The wing tip ribs can be dimpled, locations where the top skins are overlapped can be primed and the bottom wing tip skin with all the tabs that require being bent to various angles can also be worked on.
                                   The three top skins were stripped of the blue protective film where the skins
                                          will be overlapped, then primed and set onto the right wing skeleton to dry.
Dimpling of the right wing’s forward tip rib was accomplished using the same procedure as on the left wing. The pneumatic squeezer was used with a ‘no hole” yoke. A female dimple die of the type for use with a nail and hand rivet puller was set onto the male die for centering and then the squeezer was activated so the plunger was pushed into tape which was placed on the yoke. When the squeezer is activated, the pressure on the die squishes it into the tape. This is quite effective in holding the female die in position because it is literally glued in place by the sticky tape.
                                          About to dimple the right wing’s forward tip rib using the pneumatic squeezer
                                          and a “no hole” yoke with tape on it to hold the female dimple die in place.
                                  Outcome of the dimpling of the right wing’s forward wing tip rib – looks good!

Monday, April 29, 2013

Preparing Shielded Cable For Landing Light & Tweaking Right Landing Light Mounting Ribs

The holes for the right landing light mounting ribs turned out to be much closer to spot on than the holes for the ribs on the left wing. Believe this is due, in large part, to the method used to align the template. However, after temporarily placing Clecos through bottom rivet holes only, there was still a small gap between the ribs and the top wing skin ... not quite as much as there was on the left wing but a gap none the less. This is certainly preferable to a bulge and honestly, it is really fine … so most RV-12 builders will likely rivet and move on but the decision was made to make .040 shims and place them between the wing skin and the top of the landing light ribs. The trial fit went well so the shims were then dimpled and primed. Admittedly, it would be easier to place the shims under the landing light ribs because there are only two holes on the bottom of the ribs as opposed to three on the top. However, shims placed on the bottom will be visible … but one would have to get on their hands and knees before seeing them on the top, so that is where they will be placed.
Drilling holes in the shims that will be used to close the small gap between the landing light ribs and top skin.
Successful trial fit of landing light ribs with .040” shims in place above the ribs.
After the trial fit, the shims were dimpled as well as the W-1203R wing skin using the dimple dies that have a hole in them for a nail that gets pulled with a hand rivet puller. The eight screw holes that will secure the landing light lens were also dimpled for #6 screws.
Getting ready to set a dimple into the W-1203R wing skin for the flush rivets being used on the RV-12 project. The hand rivet puller will pull up on the nail going through the dimple dies, squeezing them together, thus creating a dimple.
After finishing all the preparations for mounting the landing light ribs, attention was turned towards wiring of the landing light’s Molex electrical connector. As with the landing light placed into the left wing, shielded cable is being used. Not sure if the wig wag mode generates noise in the electrical system as does the wing tip strobe lighting, but since I have the shielded wire, it is being used.
Questions have been asked about the process of preparing the shielded wire, so photos were taken of each step utilized. First, three to four inches of the Tefzel coating is lightly scored with a razor knife and I mean lightly … don’t go into the shielding. The Tefzel at the very end of the cable is then cut all the way so it can be grabbed and pealed back. It may be necessary to deepen the score in spots to get the outer coating to peal evenly.  Next the shield is pushed up and opened so the wires inside can be fished out one at a time. Heat shrink is placed over the shield then its pulled back and the transition point is dressed with another piece of heat shrink. Pictures are worth a thousand words….
Tefzel shielded cable about to be prepared for the landing light’s Molex electrical connector.
Using a razor blade knife to lightly (and I mean lightly) score about three to four inches of the Tefzel coating.
Outer Tefzel coating removed without cutting the thin shield wires.
Shielding is then pushed up the wire so it bunches up.
                                         The thin shielding strands are carefully pushed aside, trying not to break
                                          any of the strands, to create a “hole” revealing the inner wires.
 A small jewelers screwdriver or similar object is used to begin drawing the wire out of the “hole”.
                                      After a loop is obtained, the wire can be completely pulled out through
                                      the "hole". This process is repeated for the remaining wires.
Once the wires have been removed from inside the shielding, the shielding is pulled tight making it a long braided wire.
Using a heat gun to cover the shield wires with black heat shrink tubing.
The shield wire is then pulled back parallel with the cable and a piece of heat shrink is used to dress the transition point.
Heat shrink with wire designations printed on it is then placed onto the wires.
A more frugal way of designating the wiring is to use a printer to print designations , then cut the paper and place it under clear shrink tubing.

Crimping .062” Molex connector pins onto the ends of the wires.
Presto … finished Molex connector for right wing’s landing light in place and ready to be connected to the landing light.

Prior to mounting the landing light tomorrow, thought it would be prudent to test the light using a couple of 9v batteries wired in parallel.
Yep … the lights work … now try the horn!

Sunday, April 28, 2013

Pete’s RV-9A Makes Successful First Flight!!

Those following the DOG Aviation Blog know from time to time references have been made to Pete’s RV-9A project. After retiring (and still living in California) I gladly, and with much glee, spent countless hours over a period of a hand full of years pounding rivets and aiding Pete assemble his state of the art Van’s RV-9A.

Pete’s RV-9A slipped the surly bonds of earth and took to the air for the first time yesterday and successfully carried Pete on its maiden voyage into the blue wild yonder.  Sadly, I was not there to witness the momentous occasion or to see the huge RV grin I’m absolutely sure was permanently etched onto his face.

Pete forwarded a short QuickTime video taken by Keith (who visited DOG Aviation last month) of the first landing in his RV-9A at Cable Airport in Upland California. Pete greased the landing and reported in an Email to DOG Aviation the airplane had no temperature issues, engine ran strong and smooth, and the RV-9A flew straight and true in trim at 179 miles per hour true airspeed. Pete said summing it up in one word that it was …. AMAZING!!!
A short QuickTime video of Pete’s first landing in his awesome RV-9A.
For those interested in seeing the complete and well documented building of Pete’s RV-9A, visit www.myrv9.com to see the complete building process.
                                             Pete’s RV grin after having a successful first flight in his RV-9A.
Can’t wait to see what it looks like painted after initial flight testing is completed.
Congratulations Pete, she is a wonderful bird!!!!!!!!!!

Saturday, April 27, 2013

Right Landing Light Lens Fitting

The reshaping of the landing light lens for the left wing’s light was a pain … here again there has been a few weeks to come up with a better way to fit the lens.  The lens was inspected closer and it was determined the process of bending the lens at the factory left the lens not only over bent but it also created a small rise at the far outer edges in the area of the leading edge. I think this went unnoticed the first time around and contributed to my fighting with the lens to get it to set flush (or close to) on the inside of the W-1203 skin’s leading edge.

First the lens was coated with painters tape to prevent unwanted scratches while working on it. Knowing that quite a bit of material is ultimately removed from the lens, the outer edges of the lens were zipped through the band saw to remove the portions of the lens that were raised from the bending process … while at it, most of the material that would ultimately be removed anyway was also removed. Now having flat Plexiglass to work with made the rest of the process much simpler than last time.
Using the band saw to trim the excess material off the landing light lens prior to reforming the lens with heat.
Earlier in the morning the DOG Aviation R&D department played around with scraps of Plexiglass from the first lens after placing painters tape on them. It needed to be determined if using a heat gun would fuse the tapes glue into the Plexiglass when it got hot enough to reshape a bit … it does not.
Donning a pair of gloves, the lens was heated up with a heat gun set to low until it was good and hot (but not pliable soft or almost melting) and the bend was gently relaxed a bit. The Plexiglass was given a good heating a second time and then pressed up against the leading edge of the wing to cool … it dawned on me the perfect shape the lens needed to be was sitting right in front of me … staring at me. Because there is a tendency for thicker Plexiglass to want to go back to its original shape, the process needs to be repeated a few times. The end result was a much faster and better initial fit than the lens for the left wing.
                                      Holding the hot Plexiglass lens firmly up against the wing’s leading edge
                                      to cool so the lens gets reshaped to match the wing's leading edge curve.
After the landing light lens was reshaped, it was placed behind the cutout in the W-1203 skin aligned for best fit then drilled and secured with Clecos.
Match drilling the right wing’s landing light lens to the holes in the W-1203 skin using a special Plexiglass drill bit.
The landing light lens was drilled to #30 then the holes are re-drilled to #27 because screws will be going into the lens. After drilling the holes out larger, the lens needs to be machine countersunk. This is because the W-1203 skin gets dimpled for a #6 screw … that dimple will rest into the countersunk portion of the lens. The #6 screws that secure the lens have a 100 degree taper so the #27 countersink bit was installed into the countersink cage and all the mounting holes in the lens were machine countersunk to accept a #6 dimple. A scrap piece of aluminum was dimpled to a #6 for the purpose of being used as a gauge to set the countersink cage to the proper depth for machine countersinking the lens holes.  After the right landing light lens was countersunk, the left lens was removed from its resting place and also countersunk.
                                           Using the countersink cage with a #27 bit to machine countersink
                                            one of the landing light lenses clamped onto a piece wood.