Michael – Page 69 – RV8-Hangar

Mid Fuselage Work

Posted on October 1, 2014 by Michael — No Comments ↓

Time: 6 Hours

Today I started with debuting all the edges and large holes of the two mid fuselage side skins. Not too much to show with that process so there are no photos of it. When I finished that work up I ran to Home Depot to grab a 4′ section of 3/4″ x 3/4″ aluminum angle for the bending of those skins. The plans give you several measurements that you use to make some lines for reference as you bend. The first is a line 1/4″ below the rivet line that lies at an angle. The other is a line that is 5/8″ up from the bottom of the skin.

The plans then tell you to bevel the two edges of a 2″x4″x24″ board at 45° angles. I then cut two 24″ pieces out of the angle I just bought.

I then clamped the skin between the workbench and the beveled 2″x4″ board on the line I drew below the rivet line. With the skin in place I clamped one of the 3/4″ angles to the underside of the skin lined up with the 5/8″ line I drew.

I matched drilled to two outside holes of the skin to the angle so they matched. I removed the angle from the skin and clamped it to the other angle and match drilled the two holes so that the two angles now match the skin. I also had to cut the web on one end of the top angle so that as the skin/angles are rolled that it wouldn’t interfere with the wood.

I replaced the two angles to the skin, checked them and added 3 clamps to hold it all together. I then grabbed my large vise-grips and placed them at the aft end of the angles. I used the vise-grips to rotate the skin slowly. I made this process in several steps rechecking the bend. The goal is to have a conical shape starting with an 1/8″ forward to a larger come aft.

The plans say it’s better to under do the bend than over do it. I stopped short of 90° and was very pleased with how it looked. I removed all the parts and repeated the whole process on the other skin making sure that I did the bend in the proper direction so I ended up with a left and right skin. Before I could put these skins on the seat structure I needed to drill a 2 5/8″ hole in the right outboard seat rib and the right side skin. This will allow a tube for fresh air to run from the NACA vent in the right wing thru to the eyeball vent for the passenger. Van’s punched a hole in both pieces so all I had to do was break out the fly cutter and make the cuts.

With that done I checko’ed the forward and aft outboard ribs in place as well at the edge floor support that runs along the top of those ribs. Now that they were in place I could add the side skins. I was very pleased at how the bend looked when installed.

I then added all the substructure to the side walls including the arm rests, side bulkheads, aft bulkhead, floor side support and gussets.

Another fun day in the Hangar and things really taking shape. Here is a view of the hole fuselage with some skins on. I have to fly the next couple days and have training next week so the build will be on hold for a week and a half but I will hit it hard when I’m back.

Mid Fuselage Side’s

Posted on September 30, 2014 by Michael — No Comments ↓

Time: 4 Hours

Today I started on the fun deburring process of all the parts that make up the mid fuselage side walls including the bulkheads and arm rests.

I then countersunk all the nutplate holes in the various parts that I just deburred. When that was all done I grabbed the side skins down from the ceiling racks where all the flat skins get stored.

I got the soldering iron out and removed the blue film on the exterior side just over the rivet holes. The inside of the skin I removed the entire film as I will be priming and painting the surface as it will be seen in the cockpit area.

That was enough for today. Tomorrow I will debur all the skin edges and roll the aft corner of the lower part of the skins. This will make the transition from square to rounded edges for the tail cone.

Longeron Drilling #2

Posted on September 29, 2014 by Michael — No Comments ↓

Time: 6 hours

I finished up the left lower longeron today by removing it and Deburring all the holes and edges. I also deburred the holes in the lower skin and weldements where I had drilled through. One last task before reinstalling the longeron to continue the build was to round over the last 2″ of the aft end of the longeron. This is done so the skin that starts to roll up here makes a nice transition and doesn’t have a sharp corner.

I marked off the section and hit the scotch-brite wheel and made the transition.

I put that longeron back in place with clecko’s and the temporary bolts in the forward section. I also put the 2 flush screws in place at the gear tower weldement. When I was done with that I repeated the entire process on the right side with nice results. I then grabbed the spacer that goes between the gear tower weldement and the gear tower plate and deburred both the left and right one. I also reamed all the 1/8″ holes in the gear weldement to clean out all the powder coating. I then placed the aux longeron, spacer and plate in position on the left side. You clecko from the inside to make it easier to put the skins on for fitting. I repeated the process for the right side but had an issue. When everything was in place the aft end of the longeron was almost a 1/4″ higher than the gusset it will be riveted to.

After discussions with my buddy Glen we decided that it was the spacer that was preventing the longeron from settling where it needed to be. My guess is that the weldement is off just a little and it’s tweaking it a little. So my fix was to shave off a little of the spacer so the longeron could slide down as needed. I made several small attempts at this until I got it just right and the fit was good.

After match drilling a few holes on the mid-braces I separated the center section from the forward section and cleaned up all the mess.

The next step in the plans are to build out the walls of the seat section including the skins, vertical bulkheads and arm rests. I took some time and located all the parts for this section.

That’s where I called it a day as all those parts need deburring which I will get to in the next couple days. Another good day and Fall is playing nice with beautiful weather.

Longeron Drilling #1

Posted on September 28, 2014 by Michael — No Comments ↓

Time: 4 Hours

I got 4 hours in the Hangar before giving to grabbing the Harley and hitting the road to see the fall colors on this 80° Sunday. First up was to do some final tweaking of the 2 aux longerons. I wasn’t happy with the way they were lining up with the aft gussets and needed a little twisting for them to line up just right. After that it was time to line up the lower longerons and clamp them into their final position for match drilling. You want to make sure the longeron is tight against with engine mount as well as the gear tower weldements. I used various type clamps to hold the longeron in place after lining it up.

You start with the aft most hole of the bottom skin and drill up using the skin as a guide into the longeron. You then move to the forward most 4 holes that go through the skin, the longeron and the engine mount. Opening those holes up with a #12 drill to allow for AN3 bolts. I inserted the forward and aft bolt in those 4 holes to maintain the longeron position.

Now that I had the forward end and aft end locked down I just worked my way down the longeron drilling each hole and cleckoing them as I went.

There are 2 holes drilled up through the gear tower weldement that got opened up to a #19 hole. These will have screws in them and will need a flush head on the underside of the skin. This will allow the landing gear to sit flush on the underside. So after drilling those holes I grabbed the #19 countersink bit and cage to drill those holes.

That’s where I stopped and went for the Harley ride. Not a whole lot today but any work in the Hangar is good!

Longeron Bending

Posted on September 27, 2014 by Michael — 4 Comments ↓

Time: 6 Hours

There are 4 longerons, aluminum angle, that run along each side of the aircraft. These structural angles tie all the parts together and create an incredibly strong substructure. On each side there are a lower longeron running from the firewall aft to the center section at the bottom of the gear tower weldements. A mid longeron that runs the same length on the top of the gear tower weldements. A upper longeron that will run from the firewall to the tail cone and a aft mid longeron running the length of the tail cone. The lower forward is the first up and comes with a bend already in it for the bend in the floor. You have to create a couple twists, one at each end as well as spreading the angle at one end open. Van’s gives you the angles in relation to 90° to make the twists. I bought some bench vise jaw protectors that are plastic and have magnets to hold them in place. I also bought a 4lb dead blow hammer and a 15″ adjustable wrench at Harbor Freight.

The first bend is on the forward end at 7.25° off of 90°.

You then place the aft end, open face down, on the cement floor and use the dead blow hammer and hit the vertex of the angle and essentially open up the face and increase the angle. There is a guide on the plans for the correct angle and I just kept at it until it was perfect. Now you can put the twist in the aft end that you just opened up. It is in the opposite direction at the forward end. After a few trial fits and a little bit of tweaking I got the left side just right.

I repeated all those steps for the right side.

I then moved to the aux middle longerons, they just needed a little curve placed in them. I didn’t take any pictures of that process but just used the bench vise and a little pressure at 2″ increments to make the bend. I then grabbed the 15′ long longerons to do their bends. There are 4 bends that need to be done per longeron. There are 2 reference spots measured from the forward end. At each of these spots you have a bend in not planes, horizontal and vertical. I laid out a chalk line on my garage floor and used tape to make some reference lines. At the end I used tape to make 4 different measurements from center that represent to amount of deflection for each of the 4 bends.

I used the bench vise and my dead blow hammer to make all the bends. I worked in small increments and checked my progress. All in all I think they turned out good and will tweak them as needed as I install them with the aft tailcone bulkheads.

There are plates that cover the outboard edge of the center section bulkheads and the gear tower. You need to curve the top of these plates to match the curve of the bulkheads. I used a piece of oak 1×4″ wood and two 1/8″ aluminum pieces to create a bending tool.

I placed all the plates in place as well as the 4 lower gussets and the 2 larger upper gussets, which needed curving as well.

I then clekoed the forward section, center section and seat substructure to each other.

That’s where I stopped today, another great day in the Hangar. On a side note the RV-8 is not the only thing requiring metal work lately. While on my 3 day trip to St. Louis I was putting the engine covers on our Lear Jet 45 when I struck my head on the underside of the left engine on a oil drain tube the size of my pinky finger. After running my hand on the freshly made ouch I realized I was bleeding pretty good. Low and behold I had a 2″ laceration on the top of my noggin. This required 9 staples to repair and a stupid painful tetanus shot.

Total Time – 1938 Hours

Empennage Total – 218 Hours
Horizontal Stabilizer – 83 Hours
Elevators – 53 Hours
Vertical Stabilizer – 22 Hours
Rudder – 37 Hours
Fiberglass – 23 Hours

Wings Total – 536 Hours
Wing Structure – 216 Hours
Fuel Tanks – 135 Hours
Ailerons – 53 Hours
Flaps – 42 Hours
Wiring – 11 Hours
Fiberglass – 56 Hours
General – 23 Hours

Fuselage Total – 1184 Hours
Canopy – 124 Hours
Engine: 115 Hours
Cowl – 64 Hours
Firewall – 62 Hours
Firewall Forward – 16 Hours
Forward Section – 285 Hours
Center Section – 57 Hours
Seat Substructure – 27 Hours
Mid Fuselage – 131 Hours
Aft Fuselage – 190 Hours
Wiring – 113 Hours