SkyoteLog: Elevator Travel Stops

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

To receive email notices of new posts just enter your email address in the block at the left. It will be confidential, only Google will know!

Wednesday, December 7, 2011

Elevator Travel Stops

When the elevator travel stops are installed the tail feathers will be ready to cover. The horizontal stab/elevator assembly was clamped to the welding table and leveled. A digital level was used to measure the angle of deflection.

I decided that the travel stops could be simple shims of the appropriate thickness to fill the gap between the elevator horn and the main spar tube of the horizontal stab when the elevator was at it's travel limit. The shim thickness was determined by inserting feeler gauges when the elevator was deflected the prescribed 24 degrees up and down.

The down stop needed a .160" shim and the up stop needed a shim .068". A collar was lathe turned to have a 3/4" ID with a .160" wall thickness. A sanding belt was used to reduce a portion of the wall thickness down to .068" thickness at the point of contact with the elevator horn. Half was cut away leaving a one piece shim to accomplish the up and down stop function.