First new wing ribs installed
Yesterday I glued up the first two new ribs with the corner blocks. It was a little tricky getting the clamps set, but easy to adjust once they were in place. I'm using the West Systems epoxy and it is a bit different than the T-88 that I used on the Airbike. I've got the longer curing hardener, but with the temp in the garage around 85 degrees, it would fire off after about twenty minutes. I had to work fast and have a plan, or end up wasting some glue. It's nice that after a couple hours, I can pull the clamps. I usually didn't remove clamps until the next day using the T-88.
Here's a picture with the two new ribs and the tip rib. The tip rib isn't glued yet.
Teardown complete
My dad helped me finish the last of the teardown on the Pitts fuselage. Now that everything has been removed, I can start working on updates and clean-up. It's not quite a clean slate, but pretty close.
Ribs fit on first wing
I finished up the new ribs for the Pitts lower right wing today. They are ready to install, but I need to order up some corner blocking sticks first. In the pictures, you can see the details of the spar extensions for the square wing tips. The splices still need the plywood doublers. I plan on installing the ribs and possibly the doublers next weekend.
Pitts cabane stiffener
The Pitts had a cabane stiffener that was mounted on the upper wing attach bolts. It consisted of two 1/2" tubes welded to plates on each end that butt up against the inside wing attach brackets. Because the bolts are above the bottom of the airfoil, the tubes were curved slightly to keep from touching the bottom of the wing. It may have been sufficient for stiffening up the rear cabane, but it seemed like on odd part that was a non standard solution to a known issue.
Today, I fit a new stiffener made from 5/8" X .035 4130 and welded it near the top on the left side of the cabane. This is the solution I'm familiar with, though I've seen a variety of tubing sizes used. The new stiffener is without a doubt superior to the old part. It is out of the way when installing the fuel tank and also opens up access to the wing tank vent and flop tube connections. Installing the fittings for the wing tank was a real chore with the old part in place.
I also did some prep work on the backup lap belt mounts. They need to be moved lower and further back than their current location. The Hooker lap belts are a little too long and I use up most of the adjustment getting the second belt snug. I ran out of time to do the welds, but that should just take a few minutes when I get out there this weekend.
Squared off elevator tips
I got out to the hangar tonight after work. I cut the rounded portion off of the Pitts elevator tips and fabbed up the new squared off tips. They came out very well and were easier to do than I was expecting. My dad stopped by and gave me a hand. He helped with more of the fuselage tear down. He pulled the rudder pedals and associated parts, the rudder cables, the wobble pump and also the smoke pump and lines. That knocked out most of what is left to remove.
Here's a picture of the new elevators and rudder.
Spar glue up
Made the extensions for the rear spar on the bottom right wing for the Pitts tonight. Got them glued to the scarfed rear spar. It looks pretty good so far. I need to finish up the new ribs and get them installed. That will be enough to start working on the first aileron.
Getting Hirth ready to ship
I brought the Hirth home the other night and got it cleaned up a bit. After sitting in the hangar for so long, it needed the dust and grime knocked off before shipping to Matt at Rec Power for a once over. I'm hoping the internals still look as good as the outside. I suspect that rust on the crank may be an issue by now because of the humidity here in Dallas. Judging from the prop flange, there is bound to be rust inside as well. I'll find out soon.
Finished rudder ribs
I managed to finish up the ribs on the rudder this afternoon. I will need to trim down the arms on the bellcrank for the tailwheel later. I'll wait until I've got the gear dialed in before doing that bit. No surprises and it all stayed straight. There are a couple more pictures in the Rebuild gallery.
Another rudder rib and Airbike progress
I got rib number two made and welded. Amazing how long it's taking me to get that finished. It must be the result of only working a couple hours a week.
I decided to see what it would take to get the Hirth engine back on the Airbike. It was running when the Airbike was disassembled, but that was four or five years ago. Since then, it has been sitting on a dolly in the hangar. I emailed Matt at Rec Power to see about getting a gasket and seal kit to let me do a full teardown and inspection. He offered to do it for under $300 and that includes labor and new gaskets.
This seems like a good deal since he sees the inside of these engines all the time. He is a better judge of the state of the parts than I am. Chances are good that the crank is rusted and needs to be replaced. If that is the case, the price of the parts will determine whether it gets fixed or not. If the crank and other internals are still servicable, then I'll start getting the Airbike back together immediately. It shouldn't need much other than the usual maintenance items. I'll replace all the fuel lines, filters, etc. The tanks need to be cleaned out. They had auto gas in them last and it gunked up the tanks.
The rest of the work will mostly be cleaning it up and replacing a few bolts that got re-assigned to Pitts duty. The covering and paint is still in great shape and just needs to be washed. As long as the engine hasn't been junked from lack of attention, I could be flying the Airbike again pretty soon. Just have to wait for the results from Matt's inspection.
Here's a picture of the rudder with rib number two.
New tailwheel mounted
I got out to the hangar for a couple hours tonight. I was able to get the tailwheel spring drilled to mount the new tailwheel. It took a while to drill through the steel spring, but it worked fine. I used a clamp-up drilling guide to keep it square. There is still some work to do on the spring mount, but it is pretty close. The old tailwheel horns on the rudder need to be cut down. They extend down too far for the new setup. That will be an easy job.
You can also see the first rudder rib that got welded in last weekend. I ended up working on the wing ribs last Sunday, but this week, the plan is to finish up all the welding on the rudder and move on to the engine mount and landing gear details.
