Replies to This Discussion

Permalink Reply by Rick George on April 8, 2014 at 9:18pm

Sherman,

I found that much of the 750 construction does not lend itself to solid flush rivets - many of the components don't allow access to the backside of the rivets. I did use solid flush rivets on the fuselage diagonals and the wing skin doublers because it was easy to do. I did not consider using countersunk pulled rivets. I felt it was venturing too far from the designers intent, and not wanting to "engineer" and test strengths. Besides - I'm rather lazy - pulled rivets are sooooo easy!! 

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Permalink Reply by Sherman F. Childers on April 9, 2014 at 6:42am

 

Rick,

      Thank you for your response. What you say makes perfect sense.

                 Blue Side Up,

                                       Sherm 

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Permalink Reply by Doug MacDonald on April 8, 2014 at 10:15pm

I flush riveted rear fuselage on my 701 but not for performance, more for ease of cleaning the large flat surfaces.  The first time I saw Chris Heintz talk at Oshkosh he pointed out that flush rivets on a 200mph RV made complete sense but on a plane with a VNE of 110-125 mph as found on the Zenith STOL aircraft, flush riveting makes no performance difference at all.  

Flush riveting adds a bunch of time to the build so limiting its use speeds the project along. When I start my scratch built Cruzer I plan on flush riveting much of the structure but I am not going to be in a rush as I already have a plane to fly.  Also , since the Cruzer is faster than the STOL aircraft, it might actually help with performance (still not at the magic 200mph though).

The other issue to keep in mind if that the Zenith planes are not designed with solid rivets in mind.  Much of the structure does not have adequate access to the back side for solid riveting.  RVs are designed to be solid riveted so therefore there is access to the underlying structure.  Zeniths, not so much.

If this is your first build, go with the way the kit is designed as custom work can add significantly to the build time.  If you have some kit experience and want to experiment, then go for it.

Hope this helps

Doug M

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Permalink Reply by Sherman F. Childers on April 9, 2014 at 6:42am

 Doug,

      Thank you for your response. What you say makes perfect sense.

                 Blue Side Up,

                                       Sherm 

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Permalink Reply by John Austin on April 9, 2014 at 8:19am

As I'm often known to say, " Remember, you're building a pickup truck ... not a Ferrari!"  ;>)

John

N750A

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Permalink Reply by Sherman F. Childers on April 9, 2014 at 10:22am

 John,

       Excellent Advice!

        

                 Thanks,

                             Sherm

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Permalink Reply by Timothy Aanerud on April 9, 2014 at 11:45pm

The turbine powered 701 that was at Airventure had flush rivets almost everywhere.  I think the article in Sport Aviation said there was a weight savings of 14 pounds too.

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Permalink Reply by Sherman F. Childers on April 10, 2014 at 5:20am

Timothy,

        Thank you for your response. I missed the Sport Aviation article. 

             More for me to consider.

                   Thanks again,

                                     Sherm

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Permalink Reply by Timothy Aanerud on April 10, 2014 at 11:49am

Scott Ehni is the builder of the Turbine Powered CH701.  The article is the April 2013 issue of EAA Experimenter.  Google for it. you'll find it.

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Permalink Reply by Jon Crew on April 13, 2014 at 1:53pm

I have a good friend that built a sonex while I built mine.  He flush riveted and I used the factory blind rivets.  He used flush pull stainless rivets.  I used the dome head stainless rivets.  I could venture a guess, that my plane has less drag with the round head rivets because his has a big dimple at every rivet as opposed to my plane having straight skins with just a round head sticking up in line with the others without a dimple at every rivet.  Additionally, with the sonex using stainless rivets, they are stronger than solid aluminum rivets.  Not so with the Zenith rivets.  

The advantage is polishing when using flush rivets.. I am not sure that polishing a Zenith with it's thin skins is the result you want?  Besides, everyone I have talked to does not like rebuffing every month.  To each their own I guess.

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Permalink Reply by Sherman F. Childers on April 14, 2014 at 5:07am

Jon,

      Thank you for this info. Interestingly enough I had originally planned to build a Sonex however I finally have focused in on a Zenith CH750 because of it's utility.

          Thank you again,

                                   Sherm 

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