Monday, July 29, 2013

Oshkosh Bound

It is once again that time of the year for the annual pilgrimage to Oshkosh Wisconsin to attend AirVenture. In past years vendor booths have been, for the most part, passed by with only casual glances at products. Now that an airplane is actually in the making, the many vendors offering shiny, cool looking, got to have state of the art goodies will now take on a whole new meaning. Visits will undoubtedly be made to Dynon, Garmin, paint vendors, interior vendors and a host of others.

Since the beginning of the RV-12 project there have been a couple of equipment changes by Van’s and new offerings. In particular, last week an announcement was made that Van’s is switching from the Garmin SL-40 radio to the new Garmin GTR 200 … so a visit to the Garmin booth is in order. This is exciting news because the new GTR 200 radio has more wattage (10 as opposed to 7), a large easy to read display along with a multi-input internal intercom which also supports stereo headsets for music and 3D audio functionality to aid in separating radio and audio alerts from the SkyView. Preliminary reports thus far … it supposedly sounds great! The new radio will also eliminate the need for the separate (and apparently not well loved) Flightcom 430 intercom unit, thus making more room in the instrument panel. Good news for those like myself who plan on installing a couple of backup instruments in the RV-12. Apparently, the GTR 200 will also support the Dynon SkyView 6.0 new capability of pushing radio frequencies from the SkyView’s display to a radio’s serial port by the push of a button thus eliminating the need to fiddle with the radio’s tuning dials.
Photo of the new Garmin GTR 200.
A new option offered by Van’s is the Dynon ADSB-470 traffic and weather receiver which is attached to the Dynon SkyView. The FAA has been busily installing ground stations around the country which transmit weather and air traffic information to airplanes appropriately equipped to receive the signals. Weather maps, air traffic, airport info and more is received by the ADSB-470 and displayed on the SkyView’s screen. Just like cell phone service, there are dead spots across the country. But if you can receive the FAA’s transmission, the information is free for the taking, unlike a quite expensive XM satellite subscription for aviation at $55 a month.

 Screen shot of the Dynon SkyView displaying ADSB weather on the right half of the screen.
There will be a plethora of items to look for while at the show …. control stick grips with switches for push to talk and trim control built in, tie down hardware, “steam gauge” altimeter & airspeed gauges for backup, a sun shade for the canopy, not to mention those items you don’t know you want until you see it.
I know I’ll be motivated to hit it hard upon the return from Oshkosh. Lots of parts are prepped and ready to prime then topcoat. All that is needed is a couple of back to back days of good painting weather and the long overdue fuselage assembly can get under way in earnest.

Friday, July 26, 2013

Prepping Fuselage Parts For Primer

This has been seemingly a lost summer as far as RV-12 production goes. Between being out of town and over two weeks of continuous rainy days not much has been accomplished except for prepping parts for primer. The rains instantly switched to mid 90 degree days with very high humidity - not good for outdoor painting … plus I had no desire to spend time in a really hot humid shop.

Now that the temps and humidity have backed off a bit, hoping to final prep parts tomorrow during the forecasted rain and have two days to prime parts and top coat a few interior panels before leaving for Oshkosh.

A choice of interior paint has been made and now it is a matter of logistics. The application data sheets for the primer says top coating should be done between the first 24 to 48 hours and the top coat paint chosen is a water reducible product and apparently does not like very high humidity … so basically the weather must cooperate for two days straight. The center channel will be top-coated and figured it would be best to do other interior components as well to make the spray gun cleanup worth while … so the baggage floors and seat pans are now being prepped for primer and top coat paint.
Deburring sharp edges on one of the baggage compartment floor panels with a file.
 Using a Scotch-Brite wheel to smooth the edges on one of the seat pans.
The F-1224- L&R baggage compartment floors required lots of dimpling where the nutplates are installed to accommodate the removable inspection plates, along with dimpling some of the holes where the side skin attaches to accomidate the flush rivets being used on the RV-12 project.

Dimpling one of many nut plate rivet holes on one of the baggage compartment floor panels.
 Using a small diamond file to file the seat belt attach slot on a seat pan.
In a photo that was posted earlier, one could see how the F1270A stiffener plate modification from Van’s is attached to the center channel. To make life easier, I’ve elected not to install flush rivets in this area because the F1270A plates are ultimately hidden by the wings. Because the forward 10 rivet holes on the left and right F-1224 baggage compartment floor panels are behind the F1270A stiffener, they will not be dimpled.

Wednesday, July 10, 2013

Seat Ribs Dimpled For Flush Rivets

The RV-12 has eight F-1215 seat ribs … four left and four right which needed to be placed into position on the bottom skin so rivet holes in the “no dimple zone” (defined in a previous post) could be identified and marked. In a nut shell, the outermost seat rib on each side of the fuselage (one W-1215R and one W-1215L) are the only seat ribs which will have all the holes in the bottom flange dimpled. The remaining three W-1215R and three W-1215L ribs will receive dimples in all the rivet holes on the bottom flange with the EXCEPTION of the three aft most holes which are within the “no dimple zone”.  Once all the ribs were marked, the bottom flanges were dimpled accordingly.
Dimpling the bottom flange on a W-1215R seat rib for flush rivets.
After dimpling the appropriate holes in the bottom flange of all the seat ribs, the components of the center section that show above the side skin doubler plate (mentioned in a previous post) were also dimpled as well as the center channel aft bulkhead.
Dimpling rivet holes of center channel components that are above the level of the side skin doubler plate.

Tuesday, July 9, 2013

Dimpling RV-12 Fuselage Components Begins

After a thorough review of the RV-12’s assembly instructions, it appears the only areas that posed complications to dimpling was the doubler plate attached onto the side of the fuselage and the doubler plates attached onto the fuselage’s bottom skin.

It has been determined the doubler plates added onto the sides of the fuselage are a non issue since they are hidden by the wing … as such, they will not receive flush rivets. However, there are a few holes in the forward portion of the W-1270D side skin doubler that can be seen from below the wing … so those holes will receive countersinks because that doubler lies on top of the W-1270A skin doubler.

The bottom of the fuselage receives 10 triangular shaped stiffener plates which come on one stamped strip and require being separated on the band saw.  The plates are labeled W-1268A to E and the hole patterns differ slightly between the plates. Of course, these parts are not installed until much later … but they need to be addressed now because they are too thick to dimple and will require countersinking for the flush rivets. Because the stiffeners are too thick to be dimpled and will receive machine countersinks, the bottom skin and internal ribs underneath these stiffeners will not be dimpled. So the stiffeners needed to be laid out on the bottom skin at this time so marks can be placed on the bottom skin defining the areas that will not require dimples.
W-1268 stiffener plates. Prior to separation, the plates need to be marked A to E according to the plans.
Separating the W-1268 stiffener plates on the band saw.
After the stiffener plates were separated from one another, the edges were smoothed on the Scotch-Brite wheel and the parts positioned on the bottom skin for marking.
W-1268 stiffeners placed in their relative positions onto the bottom skin to mark the “no dimple zones”.
After the outside of the bottom skin was marked, the skin was flipped over and the W-1268 stiffeners were repositioned so “no dimple zone” marks could be placed on the inside of the bottom skin. Now that the no dimple zones are defined, the baggage floor and seat ribs along with the forward and aft center channel bulkheads can be easily marked and dimpled accordingly.
Marking the ‘no dimple zones” on the W-1204D aft center channel bulkhead.
There are three pairs of baggage compartment ribs. The W-1223R&L ribs are not affected by the doubler plates and all the holes on the bottom flange of those ribs will be dimpled. However, the forward most three holes on both the W-1222R&L + W-1221R&L ribs fall into a “no dimple zone” and were marked accordingly for no dimples.
                                     The first three holes of the W-1221L baggage floor rib can be seen falling
                                     within the “no dimple zone” and was marked for no dimples.
Dimpling holes on the bottom flange of one of the six baggage floor ribs.

Friday, July 5, 2013

More Countersinking Of Center Section

The plans call for machine countersinking 13 holes on the aft right portion of the RV-12’s W-1204 center section using a 100 degree #30 countersink bit. All of the holes requiring countersinking are located on the upper row of holes between the two holes that were previously drilled out to #11. Van's points out the countersink needs to be just a little over 1/4" wide which allows a rivet to sink way into it. Guessing this is because the rear bulkhead is a little thicker and after it is dimpled, the dimple is not as "crisp" as it would be on thinner material. The wider/deeper countersink allows the dimples in the aft bulkhead to properly set into the countersinks. My countersink width ended up being approximately .263" well within the maximum width guidelines given in the instructions. 
Using a countersink cage outfitted with a #30 100 degree bit to machine countersink the center section.
Completed machine countersinking of center channel – fingers show span of countersunk holes.
After machine countersinking the center channel, the plans call for dimpling the corresponding holes in the W-1204D aft bulkhead. Once the dimpling was completed, I was planning to dimple the fuselage ribs along with the sides of the center section. Looking way forward in the plans reveled there are stiffener plates that attach onto the bottom fuselage skin. The stiffeners are probably too thick to dimple, so they will likely require being machine countersunk. If that is the case, the rivet holes in the fuselage ribs common to the stiffener will not be dimpled. Will need to lay the parts out and mark the fuselage rib holes that will not be dimpled.
Since the introduction of the RV-12, Van’s has made a modification to the center section by adding hardware and stiffeners making it stronger to better distribute landing gear forces.  A portion of that modification incorporates a stiffener plate which is added on top of the fuselage’s side skins. I’ve done some research and this stiffener is positioned where the wing meets the fuselage and is not visible from above the wing and only a very small portion of the stiffener extends below the wing forward of the center channel.
                                  Trial mockup of F-1270A stiffener plate onto the center section to help determine
                                  where the dimpling for flush rivets will need to begin on the center section.
Because the wing hides the vast majority of the F-1270A stiffener plate except for a few of the holes on the bottom portion that extends forward of the center channel, I’ve decided not to dimple or countersink the stiffener plate for flush rivets. However, flush rivets will be used at the few locations where the rivet holes will not be hidden by the wing and those would be hard to see unless on hands and knees. Basically, only the center channel components above and bellow the stiffener plate will be prepped for flush rivets.

Thursday, July 4, 2013

Countersinking F-1204 Center Channel

Today a little progress was made in the shop … finished up the deburring and smoothing of edges on the remaining fuselage ribs and the center channel’s aft bulkhead. The last thing remaining to do to the F-1204 center channel before priming and paint was to machine countersink eight rivet holes for nutplates which attach onto the center channel’s forward bulkhead.
                                      Machine countersinking one of the eight rivet holes which will secure four
                                       nutplates onto the center channel’s forward bulkhead with flush rivets.

The center channel’s aft bulkhead requires some countersinking as well, so will try to finish that off tomorrow and hopefully begin dimpling ribs and parts which will contact the side skins.

Tuesday, July 2, 2013

DOG Aviation Spared From Mother Nature's Wrath

Work in the shop was suspended for a couple of days this week due to the wrath of Mother Nature. The property adjacent to the DOG Aviation production facility has(had) a huge majestic oak tree which did not survive recent storms … resulting in a large section of the neighboring oak tree falling into the neighboring house. The location where the limb broke away from the tree trunk was at a node where an adjacent limb, which looms over the DOG Aviation facility, meets the main trunk of the tree. The tree’s open wound revealed the limb looming over the shop was also compromised internally, so felt it would be unwise to work in the shop until the limb was removed.
Large section of the oak tree which fell and smacked into the neighboring house.
Before the oak tree diversion, prep work began by running a couple of center section parts through the band saw to separate them for deburring. Also fished out the baggage compartment ribs and filed the edges of those smooth along with the center section aft bulkhead. Today the Scotch-Brite wheel was used to smooth the edges of fuselage parts previously filed so they will be ready for dimpling and primer/paint.
Using the band saw to separate fuselage center section parts.
 Filing the edges of holes in the center section’s aft bulkhead.
Using the 1” Scotch-Brite wheel to smooth the edges of fuselage center section parts.