Creative Speculation
In reply to the discussion: Skygate 911 [View all]William Seger
(10,923 posts)> So, you are claiming that the 50% margin of safety required for a positive load factor acting upwards relative to the aircraft results in a 122% increase in speed?
If you don't understand your own argument, nobody should be surprised that you don't understand mine. I'm not being snarky when I say that you do seem to have a serious reading comprehension problem that is rather annoying. I say "seem to" because of your reputation for being disingenuous -- perhaps you think this "play dumb" routine is better than admitting you were wrong, or perhaps you're just playing to your gullible fan club.
No, I certainly did not claim "that the 50% margin of safety required for a positive load factor acting upwards relative to the aircraft results in a 122% increase in speed." Here, I'll list what I'm claiming, to make it harder for you to deliberately misrepresent it:
- FAR 25.301(a) says, "Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and ultimate loads (limit loads multiplied by prescribed factors of safety). Unless otherwise provided, prescribed loads are limit loads."
- FAR 25.303 says, "Unless otherwise specified, a factor of safety of 1.5 must be applied to the prescribed limit load which are considered external loads on the structure."
- FAR 25.305(e) says, "The airplane must be designed to withstand any vibration and buffeting that might occur in any likely operating condition up to VD/MD, including stall and probable inadvertent excursions beyond the boundaries of the buffet onset envelope."
- By the definition in FAR 25.301(a), the Vd/Md in 25.305(e) is the limit case, not Vc.
- A "load" in structural engineering means any force that puts stress on the structure.
- Pushing a plane through air puts many loads on the structure, including but obviously not limited to the Flight Loads defined in 25.321.
- The load imposed by the dynamic pressure of simply moving through air is roughly proportional to the square of the velocity.
- If a plane's structure has been designed with ultimate loads of 1.5 times the limit loads, then it should withstand the loads created at speeds up to sqrt(1.5) times the limit case speed, Vd.
- Sqrt(1.5) is approximately 1.22.
Please refer to this list, by number, when you are pretending to represent my claims. But first, I strongly recommend re-reading them until you understand them. As it is, you're just wasting everyone's time.