Posts Tagged ‘Firewall’

Planecation 2011: Day Five

May 20, 2011

I concentrated on the F-717 lower longerons today. In the morning, I trial fit them until getting the twist and the length just right.

In the afternoon, I decided to go ahead and drill the holes for the AN3 bolts that attach the lower longerons to the lower firewall mounts. These are 3/16″ holes so there isn’t much room for error here. First I drilled a #40 pilot hole and then opened it up in steps up to a #13 drill. I used a squared piece of wood to make straight holes. Finally, I finished them to final size with a 3/16″ reamer for super clean holes. They turned out really nice. I’m super happy to get done with this step.

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Planecation 2011: Day Three

May 18, 2011

Yesterday I got to clamp the firewall on for the first time. Today’s mission was to drill it to the main structure; time to get out the ruler! I spent most of the day aligning the firewall well before drilling it. A straight firewall minimizes adjustments to the engine mount later. The instructions say to measure 5/8″ from the front face of the firewall to the end of the side skin. This is because the stainless steel flange of the firewall has minor variations in its dimension so you can’t just align the flange with the skin.

I must have put on and taken off the firewall about two dozen times as I filed the longerons and remeasured over and over. After I got it as close as I thought I could, I drilled a hole on either side of the 772 bottom skin to the lower firewall brace. This set the distance for the bottom dimension while the longerons determine the top dimension. Then I drilled all the holes in the side skins to the firewall.

With that completed I started work on the 1/8″ holes that attached the top firewall weldments to longerons. Vans has you insert rivets into the holes you’ve already drilled through the skin and longeron here to keep everything aligned before drilling into the steel.

This is as far as I got today. Progress is a little slower than I would like but these attachments are critical to get right so I don’t mind taking the extra time.

Planecation 2011: Day Two

May 17, 2011

I dropped the kids off at daycare, grabbed a Starbucks, and got back to the airplane factory around 10am. First up, I finished the leftover longeron drilling. Next it was time to trim back the front of the longerons so they are exactly 3/4″ shorter than the 770 side skins. So far so good.

I had been bothered before that I didn’t get a good crisp bend when I made the downward bend in the longerons. The side skins make a revatively sharp angle where the downslope starts at the forward fuselage. The result is about a 3/32″ gap between the vertex of the longeron and the edge of the 770 skin.

My solve was an idea I came across in another builder’s log (I forget which one). I took one of my bucking bars and wrapped it in tape. Then I clamped it to the longeron and to the sawhorse. Pulling up on the longeron and giving it a whack with the hammer I tried to get a more exact bend on the longeron. I was able to reduce the gap by about half in the end.

After that I clamped the rest of the skin to the longeron and drilled the remaining holes.

Next up I had to fabricate some straps that marry the tops of the 704 bulkhead to the longerons.

And here they are in place on the fuselage. It was getting later in the day so I just had time to get the firewall temped into position.

There’s some critical measurements to make sure the firewall is perpendicular to the trust line of the aircraft. I will be studying that tonight before proceeding further. I’m also running out of clecos so I will need to scrounge up some more as I start drilling the firewall tomorrow.

Firewall Finished!

February 16, 2009

Annabelle was kind enough to let me make some man noise over the weekend and rivet the last parts together on the firewall. I have 4 rivets to tangle with tonight where the lower center mounts are. They can’t be back riveted or squeezed, so I’ll need to don the big boy pants and do it the old-fashioned way.

Finished Firewall Prep

April 13, 2008

Tonight Annabelle helped me finish the dimpling on the stainless steel firewall.

Tasks Completed:

  • Finished firewall dimpling
  • Final test fit of firewall parts before priming

Firewall Countersinking

April 1, 2008

I finished all the countersinking tonight on all the stiffeners and gussets. The hard wood jig I use to hold the part while using the microstop in the cordless drill is working great. I started to dimple the firewall, but after a few holes trying to holding the part and dimple by myself I thought better of it. I’ll get Annabelle to help out later this week.

Tasks Completed:

  • Finished countersinking stiffeners and gussets
  • Started to dimple firewall

Finishing Firewall Drilling

February 24, 2008

Tasks Completed:

  • Finished drilling stiffeners and gussets to firewall
  • Drilled spacers, doubler and L/R F601J
  • Disassembled firewall structure for deburring and countersinking

Firewall Drilling

February 23, 2008

Tasks Completed:

  • Fabricated F601E stiffener
  • Started match drilling stiffeners and gussets to firewall

Firewall Parts 2

February 20, 2008

Tonight I snuck in an hour fabing the rest of the firewall parts. I fit and clecoed everything together in preperation for match drilling tomorrow.

Tasks Completed:

  • Fabricated the brake line doubler and spacers.
  • Deburred the remaining parts for the firewall skeleton.

Firewall Parts

February 18, 2008

I made the rest of the firewall parts including the right F601J. The sequnece of parts is pretty straight forward but it looks to be challenging to get everything lined up to drill–especially the two gussets behind 601J. Another hour of parts prep and then I can drill everything.

Tasks Completed:

  • Made F601J-R
  • Made the right spacer and brake line doubler