1.5 factor of safety?
1.5 factor of safety?
(OP)
Ok, here is a question. How did the FAA settle on the 1.5 factor of safety? Did it come from the proposed handbook for airplane design Oct 1927? Or does it even have it's origins in aircraft design? Anyone have any idea?
Nigel Waterhouse B Eng (Hon's)
Can-Am Aerospace,LLC, Canadian Aircraft Certification Centre
www.canamaero.com





RE: 1.5 factor of safety?
Regards,
Steve
RE: 1.5 factor of safety?
The plane aaw production, and combat, and did not suffer a reputation for structural failures.
Mike Halloran
Pembroke Pines, FL, USA
RE: 1.5 factor of safety?
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: 1.5 factor of safety?
The factor of safety is 1.5 as required by the FAA. The military can choose their design requirements. I've seen military aircraft that exceed limit load frequently and intentionally.
RE: 1.5 factor of safety?
Nigel Waterhouse B Eng (Hon's)
Can-Am Aerospace,LLC, Canadian Aircraft Certification Centre
www.canamaero.com
RE: 1.5 factor of safety?
RE: 1.5 factor of safety?
Although he comes at the numbers from empirical sources at the US Army and Navy, the factors he ends up using aren't too different from what we use today (Nman=3.98 instead of 3.8). Some are related to power loading, which is also interesting. Again, different terminology is used, but he does mention the "factor of safety". He used a factor of 2. That is:
"The load factor times the basic load is, then, the 'design load' or twice the maximum probably load that the plane is required to withstand."
Which is as close as he gets to saying that you multiply the limit load by the factor of safety for ultimate load.
Aeronautics Bulletin 7 was published by the Dept. of Commerce in 1934. It states:
"The minimum factor of safety for any aircraft structure or component thereof shall be 1.50 unless
otherwise specified."
And it's been that way ever since.
Why do you ask (If I may ask).
Steven Fahey, CET
RE: 1.5 factor of safety?
-RP.