A version of this article first appeared in the June 2019 edition of our free newsletter, to subscribe click here
I have been thinking about what to do about the removal of data from the public domain and the unjustified de-validation of the remaining public domain data.
Part of the problem is that we are relying on older and disparate sources of information. As they get older the FAA are getting more nervous about them (even though the materials and fasteners are made to the same standards)
I have started a second book – a companion volume to Analysis and Design of Composite and Metallic Flight Vehicle Structures.
It will be a compilation of all of the material and fastener allowables from every credible source. It will cover metallic materials, composite materials (Mil-Hndbk-17, AGATE and NCAMP data) and fasteners.
The hope is that collecting them in a referenceable volume it will retain accessibility and credibility.
We will make the book available for free for everybody.
In the last month I have digitized all of the Mil-Hndbk-5H mechanical joint data (I was sleeping too much anyway), for each set of fastener strength data I created a graph.
The reason for this was to help me spot my errors in data entry. I always like fastener strength data presented like this – I find it much more intuitive.
I have not included the fastener limit strengths – would that be useful? Let me know by contacting us
In the process of doing this I found several obvious errors in the data.
In the book we issue, these will be highlighted and corrections suggested to keep to the shape of the curves consistent for the fastener in question.
My aim is to continue with this until I have all of the public domain data collected and presented in a more intuitive format than we currently have.
I intend to cover all standard hardware and include all of the useful data from the specifications so there is no need to go hunting for the specification sheet to figure out which grade of steel that particular washer is made from.
I already have about 300 pages completed with all standard public domain specification rivets and all Mil-Hndbk-5H fastener strengths.
Next – Metallic material strengths!