June 2010 Archives

Tonight I took care of the HS ribs. First I trimmed the aft flanges of the HS-404 ribs to fit between the two front spar angles. Many builders say that one should trim less than specified in the plans, otherwise one is likely to get edge distance problems when drilling the HS-405 ribs to the HS-702 spar channel and the HS-404 ribs. So I trimmed just enough to make the ribs fit between the angles. If needed I can always trim more later.

The rest of the evening was spent with edge finishing all the HS ribs. I have to find a better way to finish the narrow notches, otherwise I'll never get through the wings in my lifetime.

The last three weeks were rather demanding, and I haven't spent a single weekend in the UK. A lot (!) has happened privately, but nothing on the plane; that's why you haven't see any updates here.

Well, anyhow. About three weeks ago I dimpled the center holes of the HS-702 spar channels and started countersinking the corresponding holes in the HS-810-1 angle. Of course I was too stupid to follow the instructions in chapter 5, so I countersank the first hole way too deep. Stopped after that hole, thinking that this can't possibly be right, and last week I ordered a new HS-810-1. It arrived three days later (woohoooo!) and tonight I tapered it, match-drilled it, and bent the ends to 6 degrees. Doing it for the second time went much faster that the first time ... The last step for today was to countersink all four center holes of the HS-810-1 and HS-814-1.

Yesterday I spent some time on the HS-702 front spar channels. First I marked the bend line and used a warding file to make the stress relief hole that is illustrated in the drawings. Funny enough, I found several builder logs on the web where the HS-702 was bent without stress relief. Probably because it's not mentioned in the text, even though I wonder how it is even possible to make a nice bend without the stress relief, since that's where the flange rounds out if you don't cut it away. Well, anyhow, here is the before and after picture:

Making the actual bend was a simple matter of placing the spar channel at the edge of the workbench and applying some pressure with a piece of wood:

I couldn't resist putting the parts together to check if I really got the angle right. And I did! It's a good fit without tension, and already looks like an airplane, doesn't it?

After spending almost a week in Germany and a couple of days at CERN, I'm back home again and even brought a cold as souvenir. Not much progress on the plane, but at least I bent the HS-810 and HS-814 angles. The plans call out for a 6 degree bend at 4 7/16" from the center, so I first marked the center and then the bend lines. With a 3/8" radius and 1/8" thickness the setback at 6 degrees is fairly small -- little less than 1/64", so I clamped the workpieces in the vise with the bend line just above the wood block:

Then I bent the angle by hand (no mallet) little by little and checked the progress with a cardboard template. It took some time, but I like the results: