Hi everyone,
Need some advice ... newby busy with my first project. I am building a Druine Turbulent (50s orginally French design, all wood single seater with cantilever wing). Or strictly speaking, completing a project that came with fuselage, tail feathers and the wing ribs.
The main spar is now finished. For those who don´t know the Turbulent, the wing has a classic laminated box spar, with a 2mm ply D-section in front and fabric and a thin rear spar behind. Although the local (Spanish) regs do not require me to do a load test, I’ll likely be happier and enjoy my flying a lot more if I do one anyway (first project, remember). Now, I could wait to do this until the wing is complete – but I’d kind of prefer doing it now, on the spar only, so that if it all goes pear-shaped and I'm left with a pile of kindling I won´t have spent many hours and lots more €€€ on a doomed wing.
Now, the question is: is there any way of calculating or “guesstimating” the load the spar on its own should be able to carry (without the ply D-section)? According to the Turbulent flight manual from Rollasons, who series produced a certified version of the aircraft for a few years, it was rated for 4.4G – so I would have thought loading the complete wing to say 5G would indicate that the build is good. Should I just load the spar to the same weight, or does it make sense to reduce this a bit to avoid breaking a perfectly good spar?
Any advice appreciated!
Regards
Peter
Need some advice ... newby busy with my first project. I am building a Druine Turbulent (50s orginally French design, all wood single seater with cantilever wing). Or strictly speaking, completing a project that came with fuselage, tail feathers and the wing ribs.
The main spar is now finished. For those who don´t know the Turbulent, the wing has a classic laminated box spar, with a 2mm ply D-section in front and fabric and a thin rear spar behind. Although the local (Spanish) regs do not require me to do a load test, I’ll likely be happier and enjoy my flying a lot more if I do one anyway (first project, remember). Now, I could wait to do this until the wing is complete – but I’d kind of prefer doing it now, on the spar only, so that if it all goes pear-shaped and I'm left with a pile of kindling I won´t have spent many hours and lots more €€€ on a doomed wing.
Now, the question is: is there any way of calculating or “guesstimating” the load the spar on its own should be able to carry (without the ply D-section)? According to the Turbulent flight manual from Rollasons, who series produced a certified version of the aircraft for a few years, it was rated for 4.4G – so I would have thought loading the complete wing to say 5G would indicate that the build is good. Should I just load the spar to the same weight, or does it make sense to reduce this a bit to avoid breaking a perfectly good spar?
Any advice appreciated!
Regards
Peter
