Orion, Billski -
Following along the (very interesting) discussion about various composite wing structures elsewhere in this section, I'm curious about weights estimation. I'm looking to confirm some numbers I've gotten for weight of full-depth foam/glass wings. I'm still early enough along that I don't really want to do a full component weight build-up yet (the wing is still changing size too frequently), but I'd like to at least be 'in the ballpark' for my early estimates.
Raymer is giving 1.6 to 2.2 pounds per square foot of wing area (reference, not wetted)
Roncz quotes 1.52 psf, also for reference area.
Do these sound about right? I've run the Cessna general-aviation wing-weight formula quoted in both Raymer and Roskam over my wing, and get considerably lower values (like about half as much: 0.78psf). Obviously the Cessna formula is geared towards optimized aluminum structures, but the difference is so significant, I'm a little uneasy. The Cessna formula takes many more factors into account - AR, taper, thickness, etc.
If not, what is the sort of number you'd use for a first-pass weight estimate for this type of structure?
Following along the (very interesting) discussion about various composite wing structures elsewhere in this section, I'm curious about weights estimation. I'm looking to confirm some numbers I've gotten for weight of full-depth foam/glass wings. I'm still early enough along that I don't really want to do a full component weight build-up yet (the wing is still changing size too frequently), but I'd like to at least be 'in the ballpark' for my early estimates.
Raymer is giving 1.6 to 2.2 pounds per square foot of wing area (reference, not wetted)
Roncz quotes 1.52 psf, also for reference area.
Do these sound about right? I've run the Cessna general-aviation wing-weight formula quoted in both Raymer and Roskam over my wing, and get considerably lower values (like about half as much: 0.78psf). Obviously the Cessna formula is geared towards optimized aluminum structures, but the difference is so significant, I'm a little uneasy. The Cessna formula takes many more factors into account - AR, taper, thickness, etc.
If not, what is the sort of number you'd use for a first-pass weight estimate for this type of structure?
