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.
Monday, August 29, 2011
The new engine mount for the Continental O-200 is fitted and tacked ready for final welding. Based on Hawkeye's aft C.G. condition and comparison to the weight and geometry of the Jab 3300, I decided to move the O-200 forward by 2" from the position specified in the plans. The plans call for 10" between the firewall and the back of the engine mount but this mount is 12".
At the risk of over doing a simple subject, I have put together a full sequence of fitting a tube to two parallel intersecting tubes using the "tube miter" software to print patterns. www.ozhpv.org.au/shed/tubemiter.htm
We are mating a 3/4" tube with a 1/2" tube. The tube miter program assumes that the 1/2" tube will pierce the 3/4" tube. This means that about 1/2 of the printed pattern will need to be discarded. Note that the tube miter program works in mm dimensions.
This is the part we need.
I use 3/8" flat stock to find the center line of the 3/4" tubes. Clamp the tube to the bench and mark each end on opposite sides. This will be used to align the patterns on each end.
Determine the length of the tube. This requires a little estimating using a tape measure and "eyeballing" the portion where the tape won't fit in. Align the pattern with the center lines on the tube and tape it in place.
Rough cut the tube on the band saw.
Grind the tube to match the pattern and check the fit. Because we are fitting a 3/4" tube to a 1/2" tube, the shaped end of the larger tube will need to be squeezed down for a better fit to the smaller tube.
I was very pleased that I managed to cut and fit all of the tubes for this mount without scrapping a single tube!
Tuesday, August 16, 2011
The short version is: I have sold the Jabiru 3300 engine and ordered a custom built O-200 to replace it!
The long version is after reviewing the cooling problems others are having with the 3300 Jab and considering my options, I decided that it is best to make the change now rather than fight it for a long time and then possibly still have to make the change. I have already sold the Jab/prop/TBI and ordered a "slicked-up" O-200 from Don Swords of Griffin, GA. More about this engine later.
Refitting for the O-200 should go quickly as the plans provide all of the details for the installation. I think that most of the cowl can be salvaged but I have already started on the new engine mount.
In retrospect, all of the extra work required to adopt the Jab has set me back about a year from where I would be if I had originally gone with the O-200. Live and learn!