As you may have read in the last post, I had a heck of a time trying to rig the fuselage. I went from the nose to the tail, squaring each bay as I moved aft. By the time I got to the tail, I could not get the last two bays to twist square.
Well, I now know why.
Philippe Villard from Saint Julien de Chedon, France was nice enough to e-mail me and give me an answer. Philippe wrote:
I greatly enjoyed to witness your huge progress made in the restoration of your Hisso powered Jenny. Hisso sounds something for a french citizen...
I'm an Aerospace Engineer,, working as VP Marketing (after a long decadence into aircraft structure design !) for DAHER , a Tier One Aerostructure company. We are also Aircraft Manufacturer (TBM 850 : the fastest certified mono turboprop) from Morane Saulnier, ante WW1origins ! Spare time is quite scarse so I'm very frustrated to be unable to finish some restoration / homebluiding projects.
I guess, following advice from guys working on the rigging of Bleriot XI or equivalent fuselage structure that you have to start from the aft end to the nose of the fuselage.
Explanation : larger the "cross section" of the fuselage, larger the counter acting momentum to recover "squareness" and eliminate twisting of the fuselage. If you work your way rearward, from the front end, the fuselage sections are getting smaller and smaller ,and momentum forces cannot counter act forces to "untwist" the structure.
Sorry for my poor engineering explanation and moreover my poor english... Just my two cents !
That made perfect sense to me. I never thought about it that way. So, those of you rigging a Jenny someday - start at the tail and work forward!
Jenny restorer Chet Peek also took the time to e-mail me. He also rigged his Jenny from the tail to the nose and it worked well for him too.
So, I loosened all the wires this afternoon and started over - from the tail - and I had the fuselage rigged in about an hour and a half.
Thank you Philippe and Chet!
It's nice to know there are people out there willing to help.
More later this week