How many g's?

[dale gleason]

I hesitate to join in this discussion, no calcium or mathematics to back up my observations, but some time ago we installed a surplus "G" meter in a J3 Cub, a "Normal" category airplane. It may be stressed about +3-1 or so. We flew out of a fairly rough grass pasture and the "dead man" recorded over 6G just taxiing, twice the rated stress load. But, the wings didn't break loose.
It takes quite a man, or woman, even with a G suit to withstand anywhere in the 9G realm for very long, and it is incredibly uncomfortable. My reference is that USAF training film where the student passes out and the instructor isn't aware of it.   dg

[Shultzie]

Henning Forbech's photo sequence tells a lot. You can enlarge it and measure the length of the airplane and the AOA.  The AOA looks like 23 degrees, the accepted stall point of an airfoil.

A standard Viko F2D is 18 inches ( one point five feet in The King's English).   The loop is 7.5 airplane-lengths in diameter.  Thus, the Radius is 5.6 feet, very close to the Holy Grail of stunt.

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The plane would need to make 90 pounds of lift to pull 63 G's.  That would trigger about 8 pounds of induced drag, which would instantly kill his airspeed, just as the data indicates.

My condolences for nappin' this high tech talk....but after reading all this....I just removed the left bank of my brain and brain stem and all seem much betta now...

[Brett Buck]

I hesitate to join in this discussion, no calcium or mathematics to back up my observations, but some time ago we installed a surplus "G" meter in a J3 Cub, a "Normal" category airplane. It may be stressed about +3-1 or so. We flew out of a fairly rough grass pasture and the "dead man" recorded over 6G just taxiing, twice the rated stress load. But, the wings didn't break loose.

     That's because the load path was through the landing gear, not the wings. But bear in mind that if it is stressed to 3gs, it can probably be expected to handle 6 gs+ as long as there is nothing wrong with it.

     Brett

[dale gleason]

Thanks Brett! "load path through the landing gear!"  Airliners are "normal" category, too, I think plus 2 and minus zero and, although I never experienced one, harumph!, I've heard of other flyers experiencing landings of much greater than 2 G, and the wings stayed on. Now I know the rest of the story.    dg