Replies to This Discussion

Permalink Reply by Jonathan Porter on January 18, 2009 at 12:48pm

I do not know about the reactions.... but.... as a training excercise with our trainee African girls we mounted a test piece of wing skin with one rivet on a rafter at the in the workshop and slung a rope 'swing' off of it - and it just broke with one girls (about 60kg/130lb) in tension/sheer - with two rivets and 100kg/220lbs it was the skin that started to tear around the mounting - NOT around the rivets. I think we underestimate how strong the rivets are. On other aircraft types I have replaced alu rivets with SS rivets when 'BCAR-S' (the British extreemist movement) insisted on higher strengths - but it seems that nobody actually had a problem (this is where 3 rivets were used to hold a jury strut on an tube and cloth aircraft).

I am sure that some techo-somebody on the site can specifically answer your question - but I also wonder whether treating the hole with Cortec or Zinc Chromate prior to inserting the rivet would absolve you of Galvanic corrosion by providing a treatment layer?

Ultimately, I think that if you are planning to stay within the prescribed limits the prescribed drawings and specs are good... Now, if you are planning to exceed Mach 2.00 that could be another matter...

• ▶ Reply

Permalink Reply by John E.Worsdale IV. on January 28, 2009 at 7:46am

Peter,
I believe your answer would be found on the Sonex site. Under FAQ's it states.

" With the stainless steel rivets against the aluminum skin, isn't there a galvanic corrosion problem?

No. We have been using this combination for 25 years and have not experienced galvanic corrosion."

That being said, I would have faith and trust in Chris Heintz that he has designed all of his aircraft with adequate safety margins. If you decide to rethink and re-engineer a well thought out design, remember that you would then find yourself in the role of an aeronautical engineer and eventually test pilot. Surely this is a good question and I have thought about it myself, but I have come around to realizing that I haven't the credentials or adequate ability to take on such an endeavor. I understand that Zenair batch tests all the rivets they supply in their kits. If you care to find out more, then I would suggest you read Chris' technical papers found on the Zenair site. Good luck.
JW

• ▶ Reply

Permalink Reply by Peter Sonders on January 28, 2009 at 8:43am

J.W.

Thanks for your information and "links".
I have faith and trust in Chris Heintz design, (otherwise I would not build a Zodiac) and I am not "re-engineering" the well thought out design. Replacing some of the AA rivets with SS rivets will strengthen the structure without adding weight and no design changes. If you pull hard on a aluminum strip with AA rivets you will rip it apart, and when you try the same with SS rivets it will not. I know it is most probably "overkill" to add SS rivets..... The Zodiac 601XL/650, when built to the plans and flying in the given limits is a very safe Airplane.

Peter

• ▶ Reply