First pieces tack welded

Quick update to mention that the lower longerons were tack welded in place yesterday! The forward gear bolt bushing alignment was also checked to ensure that the gear was going to be at the desired location:

Square channels were used as a guide to check the gear alignment:

Mark is also going to weld a reinforcement plate for my wobble pump attachment bracket that was cracked. I took the opportunity to drill nutplate holes to ease up the installation:

Next step is the final welding of the lower longeron reinforcement sleeves. Stay tuned!

Preparing the sleeves

This week, progress was made on the preparation for the bottom longeron reinforcement. The longeron section that was removed was replaced with new sections and welded in place. Also, the external sleeves were cut and trimmed to fit the shape of the adjacent tubes:

As you can see on the picture above, the forward gear attachment bushings were slid in place to check the fit. They will be welded a little longer and then will be trimmed using a counterbore tool such as this one:

In the meantime, I worked on my nosebowl attachment. My nosebowl is a two piece type such that you don't have to remove the prop to remove the cowl. When I bought the airplane, the two halfs were riveted together at the center which was kinda dumb. I decided to install piano hinges last year to make them splittable again:

However as you can see, there was some chafing with the flywheel and one side was getting close to failure. I realized this the morning I was leaving for my last contest of the year last year. I had to cut and fix a plate (therefore the two holes on the outboard edge) as a last minute fix and managed to leave on time for the contest. While the fuse is getting fixed, I took the time to work on a new attachment design (inspired on Wes Liu's S2-A I saw at the contest in question). An aluminium plate riveted on one side and nutplated on the other side.

First I determined the best nutplate location, cut the aluminium brackets, bent them and drilled them. Here is a shot with both plates clecoed in place:

Then I made alumiprep and alodyne treatments to protect them from corrosion (thanks to my friend Scott for the chemicals):

And finally riveted them in place:

The nutplates are riveted on the foward side of the top piece. The holes beside the bolt hole on the bracket above will serve as rivet head clearance holes. I will upload pictures of the final nosebowl once it's back from the paint shop.

The plan for this week is to weld the bottom longerons sleeves in place as well as the gear bushings. These will be a challenge to fix since they need to be aligned such that the gear beam is perpendicular to the fuselage axis.

The repair is progressing step by step. Thanks all again for you encourangements, it really helps keeping the morale up, especially for days like today with wonderful wx!!

Reach out and build something

Last week I received the 4130 steel tubes and plates required for the repair : ) I also took the opportunity to order new ignition cables (as recommended by my friend and Pitts mentor, François) as well as plenty of AN hardware to replace the old one:





The 1" OD X 0.120" wall tube that is going to serve as a sleeve over the bottom longerons per Steen plans is impressively massive:

I brought all this to the welding shop last week-end. My welder Mark did a great job of removing all the crap from the bad repair with minimal intrusion to the tubes to be preserved. In the process, he discovered that the lower longerons already had internal sleeves in good shape, and securely welded! This is good news since it's going to provide better stiffness continuity all the way up to the forward end of the longerons. However, the sections of each lower longerons where the side diagonals were welded were in such a bad condition that we chose to saw them off:

These will be replaced with sections of 3/4" OD X 0.035" tube (same as the longeron) over which the 1" external sleeve will be welded later on.

Next step is to perform a dye-penetrant inspection on many locations of the foward fuse to ensure we are aware of all the cracks to be repaired before welding the new tubes in place. The items I intend to focus on during this inspection are:

1. Lower longerons (in case there is more than the 2 cracks I found)
2. Fuel tank attachment bushings
3. Lower wing attachment bushings
4. Flying wire attachment lugs

While the clean up process was being finished at the welding shop, I made some work on my nosebowl at the hangar. I intend to dedicate a post on this shortly. Stay Tuned!