F-1240 Upper Forward Fuselage Skin Completed

The 18 nutplates for the F-1202D L&R panel attach strips were dimpled then riveted onto the panel attach strips using the AN426AD3-3.5 rivets called for in the plans.

Riveting nutplates onto the F-1202D-L panel attach strip using the pneumatic rivet squeezer.

Once all the nutplates were riveted onto the F-1202D-L&R panel attach strips, they were Clecoed back onto the F-1240 upper forward fuselage skin for riveting. I discovered early on the pneumatic rivet squeezer was difficult to use for riveting the panel strips onto the F-1240 skin for a multitude of reasons. Most importantly every other rivet is very close to a nutplate and it was difficult to stay clear of the nutplates and the pneumatic squeezer was cumbersome to hold upside especially with the hose pulling down. Because it wanted to snag the nutplates, I gave up on it after the second rivet and switched to a more controllable manual rivet squeezer. Riveting began in the center and progressed towards the left and right side of the fuselage.

Securing the F-1202D-L panel strip onto the F-1240 upper forward fuselage skin with Clecos in preparation for riveting.

Using the manual rivet squeezer to rivet the F-1202D-L panel attach strip onto the F-1240 upper forward fuselage skin with AN426AD3-3.5 rivets.

Because I needed to be standing on a step stool, it was impossible to get a visual on the position of the squeezer or the shaft of the rivet so the first few rivets were VERY awkward to set … and I did not have another set of eyes available to use as a spotter. So I decided to make measurements on what it would take for the bottom rivet set to clear the nutplates installed on the F-1202D panel attach strips. A red line was marked adjacent to each rivet and the rivet sets were kept at or forward of the line so the lower rivet set would clear the obstacles.  Took a lot more time doing it this way, but the end result was worth it.

Red lines used to make sure the rivet set stayed forward of the line in order to clear the nutplates on the F-1202D panel attach strips.

Almost done with riveting the F-1202D-L panel attach strip onto the F-1240 upper forward fuselage skin.

Finished – both F-1202D-L&R panel attach strips riveted onto the F-1240 upper forward fuselage skin.

Forward Upper Fuselage Skin Set in Place

After spending most of day of completing errands, was able to spend some productive time in the DOG Aviation production facility.  The F-1240C clip requires fabrication … after pondering a few options, the method finally settled upon was repurposing a drill press tool for the job. The purpose of the F-1240C clip, which ultimately becomes riveted onto the bottom of the F-1240B cover plate, is to secure the hinge pins for the cowling. The ends of the hinge pins are bent to 90 degrees and the clip is slid over the end of the hinge pins to capture them and prevents them from moving. To fabricate the F-1240C clip the plans instruct the builder to bend the clip to 90 degrees to form a V and flatten out the sides so the V is only 3/16" high.

I love repurposing tools and after looking around the shop, decided a set of drill press V blocks would fit the bill for bending the F-1240C clip. The piece of aluminum was bent to shape by compressing one V block into another.

The F-1240C clip after forming the 90 degree bend with the V blocks.

Once the 90 degree bend was formed, the wall of the V block was just about the right height (actually slightly higher) to form the 3/16" bend. The two V blocks were clamped together and the remaining bends were made using the narrow bill of the seaming pliers to flatten out the sides of F-1240C clip onto the V block.

While keeping the two V blocks clamped together, to finish off the clip seaming pliers were used to flatten out the sides of the clip.

Forming the clip as mentioned above was quick and easy. After the F-1240C clip was formed, it was match drilled to the F1240B cover plate.

Finished F-1240C clip match drilled to the F-1240B cover plate with a #40 drill.

After match drilling the F-1240C clip, the rivet holes in the F-1240B and newly drilled F-1240C clip required dimpling because the clip will be mounted with flush rivets per the instructions … however, prior to riveting it will need to be primed.

The plans say the F-1240 upper forward fuselage skin needs to be placed over the edge of a table so the edge can be rolled by hand to put a small downward curve in the skin. No mention as to where the curve should begin or how much. I posted a question on the forums and one builder said he got good results using the edge braking tool and another worked the outer 1 1/2" edge by hand a little and could not see much difference but the part fit great. That told me the amount necessary is small, so I opted to make two passes with the Cleaveland edge tool which resulted in a nice tight fit once the F-1240 upper forward fuselage skin was fitted.

Using the Cleaveland edge tool to break the forward edge of the F-1240 upper forward fuselage skin.

Having already dimpled all the necessary holes in the F-1240 upper forward fuselage skin many months ago, the skin was ready to be screwed in position on the fuselage. The F-1240 skin also performs a second task in that it is also the cover for the instrument panel along with becoming an integral part of the front panel mounting. The F-1202D panel mounting strips are riveted onto to F-1240 skin and receive nutplates for mounting the front panel components.

Screwing the F-1240 upper forward fuselage skin onto the fuselage assembly.

Securing the F-1202D-R panel mounting strip onto the F-1240 upper forward fuselage skin with Clecos.

Just after taking the above photo I realized I was getting ahead of myself in that the F-1202D panel mounting strips should have the nutplates installed first … so off it came and decided this was a good time to end the work session.

Riveting Of Panel Base & Canopy Ribs

Had a productive afternoon in the shop today riveting the panel base and associated items.  The F-00027-L&R com support brackets which have been held in place with Clecos for many weeks were finally riveted in place on the F-1202B instrument panel base. Next in line to be riveted onto the F-1202B panel base was the F-00026-L&R instrument stack angles. The instrument stack angles begin to give definition to the instrument panel.

Riveting the F-00026-L instrument stack angle onto the F-1202B instrument panel base with the hand rivet puller. The F-00027-L&R com support brackets in front of the instrument stack angles have already been riveted in place.

Work continued by way of riveting the F-1202B instrument panel base to the upper firewall and longerons.  Care must be taken when riveting the F-1201A upper firewall onto the F-1202B panel base in that the rivet’s factory heads should to be placed on the forward side of the firewall. Also, there are 8 rivet holes which are to remain un-riveted at this point in time as shown in one of the photos below.

Using the pneumatic rivet puller to rivet the F-1201A upper firewall onto the forward flange of the F-1202B instrument panel base working from the center out.

On the right side of the F-1201A upper firewall are eight rivet holes that are not riveted at this time designated with blue tape on the Clecos … starting with the third rivet hole in from the right side of the aircraft.

After the forward flange of the F-1202B instrument base and upper motor mounts were riveted onto the F-1201A upper firewall, the panel base was riveted onto the F-1255-L&R longerons. This was done without the F-1202H-L&R canopy ribs in position … however, care must be taken not to rivet the two rivet holes for the F-1202Y strut attach angles yet.

Using the pneumatic rivet puller to rivet the F-1202B instrument panel base onto the F-1255-R longeron with LP4-3 rivets.

After both sides of the instrument panel base were riveted onto the F-1255 longerons, the F-1202H-L&R canopy ribs were secured onto the panel base with Clecos. Of note, builders need to pay attention when riveting the F-1202Y strut attach angles because the rivets used here need to be much longer … they are LP4-5 pop rivets because of the combined thicknesses of the strut angle and the longeron.

Using the pneumatic rivet puller to rivet the F-1202H-L canopy rib onto the F-1202B instrument panel base. The two rivet holes in the F-1202Y strut angle with Clecos in them will require a much longer LP4-5 pop rivet.

Panel base, com supports, instrument stack angles and canopy ribs riveted in place.

F-1202Y Strut Attach Angles Match Drilled

Short work session today but managed to make more forward progress by way of match drilling both the F-1202Y strut attach angles.  The strut attach angles were riveted onto the F-1202H-L&R canopy ribs many weeks ago and now that the top of the longerons were drilled for the panel base, those holes are now used to match drill the F-1202Y strut attach angle. The F-1202H-L&R canopy ribs were secured onto the panel base with Clecos so that two holes could be match drilled into the F-1202Y strut attach angles.

F-1202H-L canopy rib Clecoed in place so the F-1202Y strut attach angle can receive two holes there my fingers are pointing.

 Match drilling the F-1202Y strut attach angle to the recently drilled holes in the left longeron.

After the F-1202Y strut attach angle on the left side was match drilled, the F-1202Y on the right side was match drilled in the same fashion. The assemblies were then removed for deburring.

Longerons Matched Drilled To Panel Base

The original task for the day was match drilling the top of the longerons to the F-1202B panel base. Before getting involved with the drilling, the plans were closely scrutinized because a small issue caught my eye regarding the F-1201B firewall shelf. The page of the plans calling for the match drilling of the panel base to the longerons also has a detail showing the mounting of the F1295-L&R stiffeners. Close inspection of the detail revealed a small issue … four rivets would need to be drilled out to install the F-1295-L&R stiffeners. Thinking I may have made yet another screw-up, paged back through the plans to the page that calls for the riveting of the F-1201B firewall shelf to have a look. The plans made no mention of leaving those four rivet holes open. There was mention of leaving holes in the firewall shelf open … just not the holes in question.

My fingers are pointing to the two rivets which need to be drilled out … this will allow the F-1295-R stiffener to be riveted to the underside of the F-1201B firewall shelf.

One can see all six rivet holes in the F-1295-R stiffener that need to attach to the underside of the F-1201B firewall shelf.

I believe this is a case where the F-1295-L&R stiffeners were added later to the RV-12 kit and the wording in the instructions had not caught up yet. Sure glad I discovered this prior to having the side skins installed, otherwise it would have been much tougher to remove the two offending rivets on each side of the F-1201B firewall shelf. As it was, the two rivets closest to the upper firewall posed a bit of a challenge because the rivets were so close to the upper firewall that the body of the drill prevented a straight shot at the rivets. Ended up using a 12" drill bit to drill out the two rivets closest to the upper firewall.

Flexing a 12" drill bit to get a reasonably straight shot at the head of the rivet so it could be drilled out.

Right side of the F-1201B firewall shelf after the two rivets were removed. The outermost row of rivet holes needs to be open like this on each end of the F-1201B firewall shelf to allow instillation of the F-1295-L&R stiffeners.

After correcting the above issue, work began on match drilling the F-1202B panel base to the top of the longerons. Following the instructions, the outer edge of the longerons were aligned with the edge of the F-1202B panel base and clamped in position for match drilling.

Match drilling #30 the F-1202B panel base to the right longeron.

Once the right longeron was match drilled to the panel base, the same procedure was used to match drill the left longeron. After both longerons were match drilled to the F-1202B panel base, the Clecos were removed and the parts were deburred.

Finished match drilling of the F-1202B panel base to the left and right longerons.

Shielded Cable Grounding Completed

Had a short session in the shop but was able to finish up the grounding of the shielded cables used for the nav/strobe & wig-wag wiring. A butt splice was used to connect all the ground wires together to a single ground point on one of the inboard seat ribs. The ground wires are a little long … but that made it easier to crimp the butt splice and the ring terminal. After the connector crimping was completed, the ring terminal was connected to the ground point on the inboard rib. Also, the stick grip and spare ground wires assemblies made yesterday were connected to the ground point on the inboard seat ribs. Once all the wiring was in place and connected, the wires were dressed with cable ties.

 

The shielded cable's ground wires all dressed with cable ties.

The other item completed in today’s shop session was finishing up connecting the ground wire to the +12 power outlet and dressing the power outlet’s wires and auxiliary audio cables with wire ties. Van's suggests securing the auxiliary audio connector to the top of the power outlet with a wire tie so that is what was done.

Auxiliary audio wires and power outlet wires dressed with wire ties.

Tying Down Some Lose Ends - Wires

Thought today would be a good time for tying down some lose ends - wiring. The accessory power socket still required a +12 volt wire connection, along with the accompanying ground wire which attaches to the ground point on the inboard seat rib.  Another lose item that required attention is the termination of all the ground wires from the shielded cables used for the strobe and wig-wag lighting.  The current plan is to group the grounds for the shielded cables together using a butt splice and run a single wire from the butt splice to the ground point on the inboard ribs.

Connecting the +12volt wire to the accessory power socket after a female spade connector was crimped onto the end of the wire.

While about to attach the accessory power socket’s ground wire to the ground point, it occurred to me I’ll need yet another ground wire for the switches in the control stick grips that were procured at Oshkosh. So not knowing if there will be a need for additional grounds down the road, decided to crimp two wires together in a ring connector so if something comes up that needs to be tied to a ground point, there will be a spare ground wire available on each side of the fuselage to do so. A contributing reason for doing this is although the ground point on the seat rib looks accessible, trying to attach the multiple ground ring terminals while holding the screw of the Adel clamp, then placing on the screw and threading the nut in place using only finger tips is difficult.

The ring connector that has the two ground wires and the ring connector for a shielded cable ground need to join the ground wire seen on the Adel clamp.

Sadly, I did not finish the job of tying down all the grounds. By the time I got to this point, the shop was very hot and humid so I decided it would be best to work on it in the morning.