SkyoteLog: Matched Hole Spar First Look!

Welcome

*****Skyote #88 gets Bronze Lindy for "Airventure-Oshkosh 2016 Plans Built Champion"******

October, 2007

Welcome to "Skyotelog", the build record of Skyote #88. I assume that you are familar with the Skyote biplane. If not, you should visit http://www.skyote.org/ for a complete introduction to this unique but elusive biplane.

The posts are presented in reverse chronological order (newest first). Or you can click on one of the "Labels" to see all of the posts concerning a specific topic. Click on any photo for a larger image.

All my building experience is limited to Van's RV's so I have no experience with building tube and fabric or "plans building". I have much to learn so take everything I write with a grain of salt and reasonable skepticisim.

I do not intend to follow a "traditional" path for the construction of #88. I intend to employ low level technology and $ to reduce the construction time and difficulty where possible and practical. By low level technology I am referring to CAD, laser, waterjet, CNC. For example:

I have purchased a complete wing spar kit from Jerry Kerr.
A rib kit from Mr. Bartoe.
Brunton Flying Wires and Drag wires from Harvey Swack.
CNC profiled tube kits for the fuselage, tail feathers and landing gear from VR3.

In addition I have converted all of the wing fittings, brackets, links, lugs etc. to CAD and had them cut by water jet. I have designed a laser cut wing spar drill template/jig which positions the five spar components so that all of the holes can be drilled in a complete spar as an assembly. I plan to continue converting as many parts as I can to CAD so that I can reduce the "hand-made" components to a minimum.

Note: As of June 2015 I have over 100 CAD files which provide 600+ water jet cut parts for the Skyote.

While it takes a little time, converting the design to CAD is a great way to truly understand the drawings. plus a huge amount of information has been extracted from the rather complex drawings. This can be a great help to others in understanding and interpreting the design.

The Skyote is uniquely suited for conversion to CAD in that a "computer" was used in it's original design. I have read that Mr. Bartoe used a HP calculator to "compute" the design and dimensions of the Skyote. The plans show all of the critical dimensions to three decimal places for X,Y and Z axes.

Amazingly, when I put the design into CAD the resulting 3D models agree with Mr. Bartoe's thee decimal place dimensions about 99.9% of the time. I have found one discrepancy but less than 0.030"!

If you want to build your Skyote as cheaply as possible, or if you enjoy handcrafting the same parts over and over again then my approach to building is not for you!

If you want to build your Skyote in the minimum possible time with highly accurate parts then this approach may be the answer. I personally get a lot of satisfaction out of organizing the project so that it can be produced accurately. Hopefully some of this work will prove useful to others in the future.

Comments are welcome. I will respond as time permits

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Tuesday, September 22, 2015

Matched Hole Spar First Look!

The "Matched Hole" Spar kit is an out-of-the-park home run! The spar cap to spar web fit is perfect and the pre-bent spar mounted fittings do the same. With the exception of trimming the spar caps for the tapered tip these photos could have been made 5 minutes from the time the spar components came off the water jet table. The extrusioned spar caps make a much nicer spar compared to the formed spar caps. Wish I had them on #88!

This is a "shorty" demo spar made for ease of transport and show and tell. All of the critical features are retained from the full 9'-6" spar. Just the long sections with nothing but rivets have been eliminated. I created all of the CAD models for these components anand built this exact assembly in virtual space so I had a good idea of what the real thing would look like. Even so I wasn't prepared for how simple and elegant it is when actually in hand

The tapered tip uses features cut into the spar web as a template for trimming the legs of the spar. No measuring or layout of any kind is required. It is "automatic". I will post more detail on this soon.