Hi everyone,
First post, so please be gentle!
After spending hours and hours in the archive, I'm not seeing anything that addresses my specific question, so I'll throw it out here.
I'm considering an adaptation of the venerable Bearhawk aircraft so that it better meets the desires of my mission. This essentially "scales up" the design 15% in all dimensions so it's roomier. As a side effect, I'm hoping to gain some useful load.
Beginning with the wing, it is an all-aluminum NACA4412 with a 65-5/8" chord, with rib spacing of 14".
I located a NASA tech note in the archive:
Relation of rib spacing to stress in wing planes (May 1, 1920) - A. Zahm
https://archive.org/details/nasa_techdoc_19930080799
In it, it states:
Doing the math, the rib spacing in the existing wing design is 1/5 of the chord as described in the above tech note. Scaling up that wing (and all of its associated innards, structural and all) 15% returns a chord of 75-1/2" and a spacing of 16", which is also 1/5 of the chord of the upscaled wing.
Given the age of the report, and that math doesn't change that often, does this remain a valid observation? Is it reasonable to use this as a starting point before going down the road?
I'm confident in the strength and the durability of the original wing, as it met failure at 6774 pounds static weight, 6.4g. Any thoughts or concerns on proportional dimension changes?
I'll address the fuselage updates in a later post, but thought I'd start here.
Many thanks and best regards,
Chris
First post, so please be gentle!
After spending hours and hours in the archive, I'm not seeing anything that addresses my specific question, so I'll throw it out here.
I'm considering an adaptation of the venerable Bearhawk aircraft so that it better meets the desires of my mission. This essentially "scales up" the design 15% in all dimensions so it's roomier. As a side effect, I'm hoping to gain some useful load.
Beginning with the wing, it is an all-aluminum NACA4412 with a 65-5/8" chord, with rib spacing of 14".
I located a NASA tech note in the archive:
Relation of rib spacing to stress in wing planes (May 1, 1920) - A. Zahm
https://archive.org/details/nasa_techdoc_19930080799
In it, it states:
Doing the math, the rib spacing in the existing wing design is 1/5 of the chord as described in the above tech note. Scaling up that wing (and all of its associated innards, structural and all) 15% returns a chord of 75-1/2" and a spacing of 16", which is also 1/5 of the chord of the upscaled wing.
Given the age of the report, and that math doesn't change that often, does this remain a valid observation? Is it reasonable to use this as a starting point before going down the road?
I'm confident in the strength and the durability of the original wing, as it met failure at 6774 pounds static weight, 6.4g. Any thoughts or concerns on proportional dimension changes?
I'll address the fuselage updates in a later post, but thought I'd start here.
Many thanks and best regards,
Chris
