Redbeard's blog

Wind Compression/machinists gone wild

Wed Aug 13, 2008 10:01 pm

[  Mood: Sleepy ]

Well done is better than well said.
- Benjamin Franklin


After getting about 10 hours of flying in the month of June, and being on track to double that in July, I ended up having to take a break due to a frayed nose wire.

I went out to Ed Levin went to the top, set up, flew a sled run, and landed all completely uneventfully. I intended to use the training hill to play with a crude camera mount the rest of the afternoon. I set everything up, moved over to the training hill and made several flights trying some different things with the mount. After the 4th or 5th flight, I took a break got something to drink and thought of calling it a day. I started to break down, then I thought of a couple more things I wanted to try. I set back up to head back the training hill…as I was doing yet another preflight, I grabbed my nose wire and it felt strange…different…I gave a good close once-over and didn’t notice anything right away. It was not “right” however. I unhooked the wire and really moved it around and found 1 broken strand. Damn. I’m done until I get a new nose wire.

Since I was grounded until I got new wires, I figured I would do some destructive testing. I really started working the wire right where it came out of the stainless “V” that rides in the leaver at the nose. I ended up easily breaking about 5 or 6 strands.

Since I was grounded, I figured I may as well make use of my time and make a GOOD camera mount for the glider. The inspiration was one of my days at Waddell Bluff. I went out on a Friday and it was blowing 35-45 mph late into the evening, the next day however was perfect. My wife came along this trip and I was wishing she could have been up there with me. It was so smooth!

As I was making diving passes along the cliff I noticed all the stones and driftwood on the beach. I slowed down and had a proper look. From the air you could see what the wind had done the day before, and was currently doing, as easily as if someone had drawn it as a description for a book. Behind each object on the beach were long lines of sand in small ridges where the stone or driftwood had slowed the wind enough to deposit sand in the lee side. Clear as crystal you could see the direction it was coming from. I think, the most interesting thing was how clearly defined the change in direction of the wind as it interfaced with the ridge and the compression lines that were drawn in the sand. At this site the wind doesn’t often blow straight into the cliff, it usually hits it at an angle, but still generates plenty of lift. Where the lines in the sand curved in a direction that was more parallel to the cliff, the compression was obvious. Not only were the lines showing compression visible, but the dead air space at the base of the cliff was clearly visible. I wish I had a camera up there, as it’s difficult to describe how clearly marked the wind movement was in the sand. I attempted to take a few shots once I was back on the ground but it was not nearly as clear from the launch.


Above is one of the photos I took from launch trying to capture the lines in the sand. Look at the base of the cliff where the wind failed to erase the human tracks in the sand.

That was the straw that broke the camels back, I had to make a mount for my camera.

So let it begin…

I broke out my trusty Sony HC96 MiniDV video camera and Canon A620 still camera and started measuring the location of the threads on the bottom. A quick trip to the garage with my Mitutoyo calipers to take some measurements of the glider, and I was ready to fire up SolidWorks. After about 5 minutes I decided to knock up some quick 2-D sketched in Graphite to work out some options. After a bit, I decided to keep it simple and went back to the 3-D modeling. About 45 minutes of head scratching and drawing, I had my CAD ready to be CAMed…



I launched SurfCAM opened my part and started the CAMing. 30 minutes later, voila, ready to cut. As I ran the verify program, I prepped my block of 7075-T6 aluminum, and set it up on the HAAS VF2SS machining center. (below)


I CAMed it pretty tight since I’m a geek/dork and I could let it run all night if necessary. I wanted it to look sexy!...Load the programs…cycle start! mosh


Above: Front side Z-Rough


Above: Front side Z finish (actually more of an intermediate tool path)

The next day I flipped it over and ran the backside programs.


Above: Backside Z-Rough


Above: Backside after the finish program


Above: The coolant we use tends to discolor the aluminum, but I thought it looked pretty cool all gold and rainbow colored. If I decide I like the mount, I intend to have it anodized, but for now I’m leaving it raw.

I happened to have a piece of tubing the same size as my keel from one of my other projects, so I drug it to work and sewed up the Velcro straps.


Above: Yes, I'm a member of the "seam-sters" union Laughing

If I end up liking the system, I will eventually cast room temperature vulcanizing rubber on the surface that interfaces with glider for some grip, but for now I will use a cleaned, sanded piece of bicycle inner tube.

This is piece 1 of 3 for the camera mount, more to follow on completion! Soon to be well done!

*EDIT*...and here it is! http://www.hanggliding.org/weblog_entry.php?e=406

Until next time, never land on your face.

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Author Message
Windlord
3 thumbs up

Joined: 20 Nov 2007
Posts: 5241
Location: Montana


PostPosted: Thu Aug 14, 2008 8:04 am    Post subject:    

That is some unreal engineering on the mount.
Ya gotta love computerized tooling, anything is possible.
Very, very nice! thumbsup thumbsup
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BubbleBoy
1 thumbs up

Joined: 31 Jan 2008
Posts: 3192



PostPosted: Fri Aug 15, 2008 5:31 am    Post subject:    

That's a piece of art Dude. Very nice.

JB
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HangDiver
3 thumbs up

Joined: 06 Nov 2007
Posts: 2152
Location: Salida, Villa Grove, Colorado


PostPosted: Fri Aug 15, 2008 8:00 am    Post subject:    

Redbeard - that is awesome. I have no talent for that kind of stuff - I'm impressed.

One Question - are the "fins" at each end needed? Will they add a little drag to the mount? Although it might be insignificant relative to what the entire mount/camera contribute....

Thanks for posting.
Rich
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soarass
3 thumbs up

Joined: 24 Jun 2008
Posts: 245
Location: Desert California
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PostPosted: Fri Aug 15, 2008 11:19 am    Post subject:    

Smile Hangdiver: If I understand the design intent here, the "fins" are called flanges, and they provide rigidity to the curved section, to resist deformation due to the velcro straps' tension, and drag/deflection forces from the camera itself. Also keeps the keel tube protected by not allowing dings from the corner of a deformed base. Any drag would, as you surmise, be negligible compared to the camera itself. Cheers, Joel
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saltoricco
3 thumbs up

Joined: 13 Jul 2007
Posts: 984
Location: Portland, OR
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PostPosted: Fri Aug 15, 2008 1:36 pm    Post subject:    

Wow, look at that part! What a beauty. Highly impressed here. thumbsup thumbsup
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