Construction progress and builder's log for my Van's RV-7 project N769WB
I finished the other taper pin on the tail wheel bracket. I also went out and bought a couple more special drill bits to open up the first taper pin hole. I was hoping that this would allow my dull reamer to work but I had no success so I ordered a new reamer.
The rest of the time was spent working on the aft fuselage bulkhead and getting parts ready to prime.
I continued working on the taper pin mod to the tailwheel mount.
A little background: normally the tail spring and tailwheel bracket are secured using standard AN bolts. This is an area that is prone to issues as the plane ages. In short the standard bolts allow a tiny bit of play but the tail wheel assembly is subject to a lot of abuse. Over time the tiny amounts of play grow larger leading to difficult maintenance to replace bolts, parts etc.
I came upon the taper pin mod in the VAF forum and decided to do it on my RV-7. The mod involves using the tapered pins (AN386) in place of the standard bolts. The advantages are that the holes for these pins are reamed, the fit is super tight and the fit is self correcting.
Unfortunately I did not research quite enough at the start and I did not realize that the parts need to be drilled out a bit to get them closer to the taper pin size. Long story short is that I spent a lot of time trying to ream the forward tail spring bolt to size and made only a little progress while dulling the expensive reamer.
Once I opened up the holes first the reaming for the pins went smoothly.
I got stalled on the first pin. After opening up the holes I was able to get the fit of the aft taper pins done with little effort.
I also continued working on fine tuning the fit of the aft most fuselage bulkhead.
I triple checked the tailwheel mount alignment (using the the autoleveling laser) and drilled the forward part of the mount to the fuselage.
This took a long time due for several reasons: I had to reach into the fuselage with the drill, the tailwheel mount is made of very hard steel, the alignment of the drill is critical - not much room for error and the hole starts out small and gets opened up to 1/4".
I went through about 7 graduated sizes of drill hits then finished the holes with a reamer.
Everything turned out great.
I also started on working on a taper pin mod to the tailwheel mount.
The tail spring mount is another part where the Van's instructions are fairly vague. I spent a lot of time studying the plans and researching on line.
I started by cutting out a section of the skin where the tail spring extends out. This process took a while to get an exact fit.
I also enlarged a hole to allow clearance for the tail spring nut.
The rest of the time was spent measuring the tail spring mount, checking alignment and coming up with a plan to drill holes for the bolts that secure the mount.
I got the seat back adjusters riveted on to the f705 bulkhead fairly quickly. I then removed a few temporary pop rivets in the cockpit.
Following this I went forward through the instructions checking off completed items and came to the tailwheel mount.
I went ahead and removed a large number of temporary pop rivets holding in the aft bulkhead then took the bulkhead out.
I also started test fitting the wd409 bracket that holds the tail spring.
I got the seat back adjuster parts and modified reinforcement plates prepped and primed.
I started to rivet various rivets that are left open on the sides of f705 bulkhead (where the seat back adjusters are mounted). I got off on a tangent when I tried to figure out if I needed any additional holes for the static system air line before riveting. I burned a lot of time researching this but I think I have a good handle on how I want to route the static air line now. This is one area that Van's instructions are fairly vague on.
I finished riveting the f705 bulkhead and the f757 reinforcement plates. Some of the f705 rivets are very tight so I opted for Cherrymax structural blind rivets in several spots rather than risk a bad driven rivet that would be very tricky to drill out.
My new longer engine mount arrived from Van's while I was at work (thanks to Britt for picking it up at Fedex). I got the new mount unpacked and everything looked good. It's about two inches longer than my original mount which should help offset the aft weight of the parachute system. Van's has been great about this whole motor mount swap. The mount is $1200 but Van's is letting me swap it for no charge other than shipping.
While I was packing up my old mount to ship back to Van's the first shipment from BRS arrived. I had time to unpack the two boxes and take a quick look. Everything seemed to be very high quality and well thought out. I'm excited to start working on installing it. The only part of the install kit that was back ordered was the fiberglass fairings that cover the suspension lines. I will order the actual parachute and rocket when the aircraft is close to flight ready.
As far as actual work on the fuselage I did get some countersinking and a few rivets done in the cockpit / baggage area.
Posted with Blogsy