Hatz Biplane Association

Oh, so THAT's what those holes are about. Thanks Jeff.

Nicl

You can measure the length needed pretty easily if you are using clevis fork ends. You'll notice there is a small hole in the barrel of the fork which is the depth indicator for the rod. When the rod is inserted in the fork and everything is tightened, try to push a piece of safety wire through the hole. If it doesn't go, the rod is inserted enough. Using this premise, put a fork on each attach point and measure between the holes to get the rough dimention to which you would add a small amount to the rod lenght to compensate for any variation.

Jeff Moore

Good morning gents.

I had an interesting experience this weekend and thought I'd pass it along in case it interests anyone else.

With all this talk of "stress risers" in cut threads, I thought I'd look carefully into it. Last thing any of us want is cracks in our drag/anti-drag wires. So I asked my son for his microscope and had a peak. I see precisely what they are now, the head end of the cut where the teeth dig in. So I picked up a couple of tiny precision files and filed out the stress risers under the microscope. That may sound like over-kill but here's the interesting part. The stress riser did not exist only in the last thread. There was always another one on the second thread as well, from the second set of cutting teeth, i'd imagine. So I filed those out as well. Now I feel very confident about the quality of those threads.

Hope that helps someone else.

Nick

Hi Hatz folks,

As we posted earlier, we cold formed our drag/antidrag wires from stainless AISI 316 material be rolling the 10-32 threads and reduceing the wire between the threads by cold forming to a 1/8" square section. Thus we achieved a weight saving of about 33% compared to a full 3/16 rod with cut threads. Strength is tested and meet the AN 703 spec!
Due to a lenght error we have to remake some wires in the next 2 weeks and if somebody is interested, we can make some more. Lenght is 40" from clevis pin to pin, but can be made different if desired. Prices depend how many we can produce in a bulk (our model streamline wire machine has to be especially set up for that purpose, so we have to make those in a row). If anyone is interested, please send an email (see http://www.aeroplaneworks.ch)
By the way: We have now compleded the wook work on all wings and are now building the aluminum ailerons. See picture included!

Hope to meet you all at Brodhead this summer!

Best regards
Hans & Sam, H.C.#78, Switzerland

Regarding cutting threads, I just read an article that says once you've cut the thread to the length you want, turn the die around and cut the last thread with the other side. This will give you a tapered end to the thread. Sounds like this might resolve the stress riser concern and the need to file out the sharp end of the thread. Has anybody heard of this method?

Nick

Thanks very much, Scott. That is, as usual, very useful.

Nick

No need for 2-1/8". I checked my completed top wings and all wires have at least 1" of unused thread. See picture below. Your 1-1/4" should provide at least 1/8" more thread than you'll need. BTW, I measured the pin-to-pin lengths and found the middle and outboard bays are approximately 39-5/8" and the inboard bay is 39-15/16".

[img]http://www.thehatz.com/gallery/albums/userpics/10002/normal_DSCI0201.JPG[/img]

Thanks Scott. Did you find you need the full 2-1/8" thread? I was thinking I'd only need about 1-1/4" on each end, but haven't acutally put them together yet.

Nick

Nick,

I just measured a Bruntons-made drag wire. 38-1/2" long. Each end is threaded 2-1/8".

-Scott

Good evening gents,

Stainless steel rods are threading like butter using a die holder in my Taig microlathe. Next question, wire length. The plans call for the drag/antidrag wires to be 40" pin to pin including clevis ends. To me that looks to be about 39" of rod. Can anyone confirm or correct this?

Thanks

Nick