Sunday, December 2, 2012

"For awhile, they were asking how long it took to build."

"Now they're back to asking when it will be done."

One of the nice things about working in the hangar on a nice Saturday morning is the steady stream of visitors that are either stopping by for an update or those intrigued by the sight of an airplane being built. Both groups have been known to ask both of the questions above, but the latter group, the first-time visitors, had recently starting to ask only the latter question.

Not anymore.

The reason for that has to do with the number of things that have been undone as I prepare to receive the new landing gear reinforcement parts from Van's. As usual, that is a somewhat open-ended commitment from Van's - they do things at their own pace and aren't always particularly precise when it comes to telling us when to expect things. It's a lot like having the cable service department tell you on Monday morning that the repairman will be there sometime between 9:00 am and..... Thursday.

"They'll be there when they get there," if I may paraphrase.

No sense lying idle while waiting, though. The landing gear legs are off already, as you may recall, so this weekend I did the next couple of steps. Van's seems to have decided to address all issues with the landing gear installation big and small, and one of the smaller ones was a slight interference between the two big landing gear attachment brackets and the large end of a few rivets. Rather than have us remove the rivets (which wouldn't be easy or smart), Van's has us grind the edges off of the steel brackets.

That may be smart, but it's not necessarily easy. It involves the grinding wheel - one of my least favorite power tools. Parts being ground (grinded?) get very hot, there are a lot of sparks flying around, and I'm always a little nervous that something is going to break and get flung off of the wheel in the general direction of my head. And I don't need any more damage to my head, thank you very much!

As predicted, the bracket got pretty hot. I could feel it getting too hot to handle even with gloves on, so I had to set it down to let it cool off between grinding sessions. Luckily it was pretty chilly in the hangar and it cooled off relatively quickly. I filled the time by drilling out the rivets that will be replaced when the new doubler than Van's is sending to beef up that part of the side skin arrives. The gloves came in handy for that job too, but to protect them from the cold rather than the heat.

I made a special tool for drilling out the rivets based on a tool I had seen before. It was as simple as sacrificing a $5 Harbor "THE Place for Fine Sacrificial Tools and Furry Mammals"  Freight center punch by grinding down its point so that it would fit into the mandrel hole of an LP4-3 rivet.

Usually it only takes a punch or two to knock the remaining mandrel out.  Once that's done, slow drilling with a #30 bit will take the cap of the rivet off. Once that's done, another punch or two will knock the rest of the rivet out. In some cases a light spin of the drill is needed to add encouragement. Mostly, though, it's pretty easy.

Right up until it's not. In this case, the tab that the rivet went through just pushed away from the punch.

I tried grabbing the tab with a cleco clamp.

That still wasn't enough. I added the blade of a small screwdriver to the mix. That held the tab firmly enough to let the center punch do its thing.

There! One side done!

Between bouncing from grinding to rivet removing and back again, I mostly finished up the preparation for installation of the Service Bulletin parts.  The foresight and extra effort that went into getting ready for the parts before they get hear will surely be paid off with a nice, lengthy wait for the parts to get here. 

 Because that's the way these things go.


Anonymous said...

For what it’s worth, here’s a data point. I’m about five serial numbers after you, but I’ve been flying about two and a half years. FedEx emailed me on Thursday the 29th, my parts just shipped.


tec said...

Great idea on the punch tool! Thank you.



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