Adding more rivets to the park brake doubler - 3 hours

 Looking at yesterdays work...I think I need to add more rivets. The spacing is just too far apart. 

Adding extra rivets is not a big deal with the use of the fan spacer. 

Its looking much better now. Now I need to clean up all the corners and debur the holes, most important is to ensure a good fit of the bulkhead grommets. 

The fit is excellent so I need to dimple everything before priming. The stainless steel firewall is easy to dimple with the pop rivet dimpler. Just takes a lot of finishing nails as there are so many rivet holes now.

Revising the park brake location - 4.5 hours

 I struggled a bit lately on where to mount the park brake as the rudder pedal interferes with the location if I mount it in the Vans standard location. So after a bit of research, looks as if some have mounted it higher but this places it where the IO-360 mixture and prop governor control cables penetrate. So I finally decided to place the park brake in an elevated location near the bulkhead penetrations. Before I do anything, I drafted a template on AutoCAD to get the fit right before I did anything.

The initial position was too low and the result is that the brake lines interfere with the horizontal tubes of the rudder pedals.

I will need to elevate the park brake a bit. So I tested a couple of variations.

Once I was satisfied with the placement. I used the CAD drawing to cut out a doubler as the fire wall needs a bit of stiffening at that location. First step is to get the rivet holes set and the openings in the doubler sorted for the bulkhead grommets that I have. To start I used a #40 bit for all of the holes at the center points.

Using the holes in the doubler as a guide...I set the doubler on the firewall and squared it using a carpenter's square. Then I drilled and clecoed all of the holes.

Now its time to open the holes in the firewall for the bulkhead grommets.

It took some time to slowly and carefully open up the holes to final size in both the firewall and the doubler. By the time I was finished, I was really happy with the results. 

 

 

Installed the AN837-4D 45deg elbow at the gear weldments - 1.5 hours

 One task that needs to get done is to install the AN837-4D 45deg elbow at the gear weldments. One of the parts of this task that I have not completed yet was drilling the hole in the F-772 forward bottom skin. The plans have you open up the pilot hole to 5/8" diameter however I purposely did not open it up all the way. The reason why is that I wanted to make sure that the hole was perfectly aligned with the hole in the weldment. The only way to make 100% sure was to actually install the weldments (and bolt them).

Now that it is done, time to center the hole for the AN fitting and open to 5/8" diameter. So after some work with the file and the dremmel I had the opening at 5/8" and perfectly centered. 

Installing the custom fuel lines and bending the rest of the brake lines - 8 hours

I need to install the custom fuel lines from Tom @ TS Flightlines. In my request for order, I asked for the tubes to be bent to allow the lines to run along the top of the cover support ribs. The reason for this is that the top hole is the largest hole and it will give me enough space to enlarge it if necessary. 

The ends of the fuel lines require at least a 3/4" hole to feed the lines through. However the biggest challenge is in getting the grommets for the larger fuel lines. Aircraft spruce's list of available grommets is a bit limited so I have to stick with the following;

• Install AN931-8-13 for inside rib supports (13/16" hole dia. with a 1/2" inside hole dia)
• Install AN931-11-16 for weldments and the fuselage opening. (1" hole dia. with a 11/16" inside hole dia)
  

 I opened up the top-most holes in the cover support ribs to 13/16" by using a unibit. The outside cover support ribs can be simply removed, while the inside support ribs can't. This required me to use a unibit with a wrench and slowly and painfully open up the hole. 

Next I can thread the new fuel hoses through, but I can see they don't perfectly line up in the hole on the innermost support ribs. I needed to bend these just a tad by hand so the hose is centered in the new 13/16" hole. With that done, The fuel lines are slid into position and grommets installed. Surprisingly the grommets were easier to put in then I expected. 

 Now I can start measuring the brake lines that run from the bulkhead fittings in the cover support ribs to the weldment connections. Using a piece of wire I suspect I will need a 12" or longer braided line. I was concerned about how the two braided lines could rub together in such a tight space. So I decided to try bending a short hard line for this space. The bend recipe was fairly easy to figure out;

1. Start with about 12" line straightened.

2. Flair the end with a nut.

3. Bend 90deg as tight as possible (Place the nut tight against the bending tool)

4. Measure 1 1/4", bend 60 deg.

5. Measure 2 1/2", turn about 15deg and then bends up 30deg.

6. Flip 180deg and make an immediate bend of 30deg (The tube should now have a z-bend and be parallel)

7. Check fit, trim if needed. Flair the end with a nut.

The tube fits extremely well in the area with no potential for rubbing anything. It's also very easy to replicate/replace if needed.

Now I'm ready to work on the left brake line. From my previous work I had the initial bend recipe figure out. But I need to keep working on it. Figuring out this line took quite a few tries until I was happy with what I had. Here is the bend recipe for the left line;

Measure out 47" of tubing and straighten it. 

1. Align the end of the tube with the outside of the bending tool.

2. Bend 45deg down.

3. Measure 1 1/4"

4. Bend 45deg up.

5. Move the tube so that the 45deg bend now sits outside of the bending tool

6. Bend 45deg down so that the tub sits horizontal in its final position.

7. Measure 1/2"

8. Now make the bend that jogs around the angle - bend the tube aft 45deg.

9. Flip the tube 180deg and make an immediate bend 60deg.

10. Flip the tube 180deg again and bend 45deg. to complete the jog. The tube should be close to parallel with the start. (Bend by hand if necessary to get it all to sit flat on a table). 

11. Measure approximately 1 1/2", then bend down 90deg. (This dimension sets the position where the tube sits in the center tunnel area. I need mine to sit close to the angle to clear the nutplates that hold the fuel pump.)

12. Measure approximately 1 1/2", then bend the tube aft 90deg.

13. Measure 24 1/8"

14. Bend 75deg up.

15. Measure 2 1/8" and bend the tube 90deg so the tube runs to the left side of the cockpit.

16. Put a z-bend in the tube to help get the tube up and aligned with the bulkhead fitting on the outer mounting flange. (15deg bend up...then 15deg bend down to get it back parallel)

17. I also put a couple of small 10deg z-bends in the long horizontal line that sits in the center tunnel to help with clearance from ribs.  

18. Insert and mark the end for final trim. Cut as required.

19. Slide the tube back into place, install bushings and nut, etc. Rotate the entire tube to allow for the flairing tool to fit. Finish the flair.

I am super happy with how it turned out. I will need to make some spacers by 3D printing them, but will do that later. 

Installed nutplates in the cabin area - 3 hours

 Well, this is the first time I've had a chance to really work on the plane in quite a while. Its been so busy at work and if I haven't been working overtime, I'm so exhausted I cant keep my eyes open. 

So back to it. I had prep'd and primed all of the nutplates and they are ready to install on the center tunnel ribs.  

Next I need to install the nutplates I had to remove from the front edge of the F-704 center section/bulkhead in order to fit the gear weldments. Getting these in was a pain in the but just because the access is really tight with the weldments and the bolts. 

The only other nutplates that can be installed now is the two in the bulkhead recess. After drilling and deburing I used the pop rivet dimpler for the thin stainless steel. 

 

I used the alligator squeezer for dimpling the nutplate. 

The nutplate is easy to install using backrivets. 

 

Spot priming the cabin area floor - 2.5 hours

 After removing the plastic from the floor area, I noticed that I had some areas that had small scratches or scuffs. There was also an area at the front where the control column is where the plastic wasn’t on well when I applied the acid etch previously. The result is that the aluminum is a little unsightly at this area. So I decided I will buff out these areas and prime them just to be safe for any future corrosion issues that may arise.

 

Removing plastic from the Cabin Area and preparing for nutplates - 3 hours

 I need to do some priming touchup's on the cabin area floor. As well I also primed the back of the sidesteps.

I am also ready to pull up the plastic on the floor., so I did that as well. Everything gets a good vacuum as I have primer pieces everywhere. 

At the suggestion of another builder, the recommendation was to install nutplates in the centre control rod tunnel to secure future wiring. I know some folks use zip tie mounts prosealed to the side of the rib, but I much prefer the use of adel clamps where possible. After reading up on AC43.13 with respect to wiring, supporting wiring and maintaining distances from control rods. I feel confident in proceeding with installing nutplates for this area. I ended up drilling the nut plates centred in the rib vertically and two of them for each rib. I needed to adjust the spacing for the forward left rib to account for the aileron trim servo.

Received the TS Flightlines Custom fuel lines - 1/2 hour

 Today I received the custom fuel lines from Tom @ TS flightlines. I had ordered them Nov 20th so they came reasonably quick (for Canada). At first I was scared they may have been damaged as the box arrived a bit crushed.

I was relieved when I opened the box and found the cables in perfect condition. I am so happy to receive these.I don't have time to get these into the plane as work is so busy. But come the holidays I will get on it.

Started fabricating the left cockpit brake line - 3.5 hours

 I started in on developing the bend recipe for the left brake line. This one is a bit more tricky to work out as there is quite an amount of bends within the first 10" or so of tubing. I made quite a few attempts to get the bulkhead portion correct. So I don't blow through too much tubing I start by working with 10" pieces of tubing... Also straightening the tubing a re-bending to work out dimensions also helps.   

After I have the forward part of the bends worked out. I started in on the aft/spar area bends, but I was getting concerned on how to get it fit with the braided fuel lines. I don't have those ordered yet as I am waiting on a few things on my end (money) but in a few days I should be in good shape to go ahead with the order. I decided to pause the fuel line fabrication until I can the fuel lines in.

 

Fabricating the right cockpit brake line - 6 hours

 I'm really struggling with what to do for the cabin area brake lines. Originally I was thinking braided nylon brake lines. I also feel pretty confident in making them out of 1/4" 3000 series aluminum.  Each has its pros and cons. (Braided lines are easy, but they make the braking feel less firm and they don't bend corners as well. I know I will have space issues with my install. Hard lines are difficult to fit, but are cheap and fit in tight spaces). The disadvantages that I am focusing on right now are the braided line is how to insert the tubes through the cover support ribs on the front of the spar. The holes are not large enough for the fittings so I would need to do some surgery. The difficult part with the aluminum lines is getting the line through the gear weldment and flaring them in place for the fitting through the bottom of the skin.

I finally decided that I will at least attempt to make them out of soft aluminum tubing and if I fail, I'll go with the braided lines. After a couple hours making templates with scrap tubing. I finally figured out my bend recipe. I made the complete right brake line, and fit in into the plane. Getting the tube routed through the gear weldment was interesting (a pain). Turns out that I just struggle too much trying to flare that end near the weldment. Also take into the account if I ever have a leak or need to replace this line...This is likely impossible to re-do when the plane is complete. 

 

It just wasn't working to my liking, so I abandoned the idea. I was deflated. I wasn't fully on board yet with switching to braided lines. Getting the cover support rib issue worked out was not going to be fun, nor easy. After some head scratching..I though back to a suggestion from my buddy mike who mentioned a bulkhead fitting in the cover support rib could be an option. Well that does solve the impossible part of the aluminum tubing option. 

 

 I went to work again...this time using a bulkhead fitting in the most outboard cover support rib. Yes, is slightly interferes with the lower hole. But if I shave down that one flat on the fittings...Bingo! We have a solution. I started working away at making a couple of lines again and by the end I have my bend recipe for the right brake line worked out. 

Measure out 50" of tubing and straighten it. 

1. Start with flare for the firewall fitting. 

2. Measure 2 1/2"

3. Bend 45deg aft. 

4. Allow short length, bend 60deg fwd.

5. Immediately bend 30deg aft so the tube is back parallel (For and offset S bend....yes the math doesn't checkout but with the consecutive bends in my tool, the original bends relax a little)

6. Measure 3", bend 90deg down.

7. Measure 2", bend 90deg aft

8. Measure 24", bend 75deg up.

9. Measure 1 1/2" (or just a tad more), bend 90deg to the right side of the plane. This gets the line through the large "S" in the fuel supply line 

10. Measure 3 1/2", bend up 30deg, Allow about an 1" then down 30deg (For an S bend). This will allow the line to get up and through the first inboard cover support rib.

11. Measure about 2", bend up 30deg, then down 30deg (For another S bend). This gets the tube aligned for the outboard support rib/bulkhead fitting. 

12. Trim to final fit (you will remove about 3/4"). Slide on the bushing, the AN collar and nut. Then bend the tub fwd enough to allow a flare to be fabricated. Bend the tube back by hand to the bulkhead fitting.