Comment

Comment by Charles L Smith on December 6, 2009 at 11:36pm

I am happy that Zenith has decided to make an upgrade kit for the 601 XL aircraft. I
am a builder and have enjoyed this project. As I've progressed along on the fuselage
I have compaired it with the RV-12 design and noticed that the RV-12 wings have a longer spar that
goes into the main spar and are attached to the longerons. I am gradtified that there are hard attachments
being added in and around the main spar of the Zenith 601 XL. Thank you for your attention in this area.

Comment by Larry Whitlow on December 5, 2009 at 1:54pm

Greg

From my perspective, it's about the same amount of work to prep new spar webs as it is to add the pieces to the ones I have. I agree with Jake that ZAC has done its damndest to keep from changing the interior in any significant way.

In regards to your concern about your spars being different that factory new spars, things like that are the case all along. My kit (purchased in 2005) has a slightly different wing config that the first ones ( 3 instead of 4 nose ribs, different stiffener positions, thicker skins, and so on) Its the nature of the beast. The engineers find a better/stronger/lest costly way of doing something and it gets rolled into the fleet, and the new units differ from the old ones.

In short I'm very happy with the add ons to the center spar. If Zenith told me to scrap the webs and go with new ones I'd do that too

I just want to get the fleet back in the air and my aircraft reassembled with the list of mods ZAC tells me to do

Larry

Comment by Jake Reyna on December 5, 2009 at 1:34pm

Greg, I believe this was addressed in the Q&A with Matthieu. You'll have to go find the post, but I think it went something like, ZAC will be offering new wing spars and a center wing spar for those seeking that path. So, you can have it your way.

Happy Trails!

Comment by Greg P Couttie on December 5, 2009 at 10:15am

My biggest concern is given all the work involved to upgrade the existing center spar webs ,I dont see the point in doing this, there is not much more effort to just replace the webs ,period. I believe the concern is MATCHING up the holes ,granted this would be difficult, but not impossible .In a nutshell I do not want my aircraft wing spars to be ANY different from a brand new aircraft ,I dont care if it takes longer to carry out the mod .

Comment by Jake Reyna on December 5, 2009 at 8:06am

My biggest concern is that I can use the existing holes in the fuselage to remount the Center Spar and as usual, ZAC is doing an excellent job of addressing these issues. Other issues to consider are mating to the seat pan and console. ZAC has done a great job in minimizing the impact on the interior. I was expecting that a doubler would be added to the underside of the fuselage.

I'm wondering about the Aileron Control Stop, it won't be easy to install. Will this be required? Why can't we use Stops on the Rear Spar like those used for the Flaps? Will this fall under the category of, we're the Manufacturer and can create our own solution as long as it accomplishes the goal. Would it be possible to add an adjustable stop to the Aileron Bellcrank, like an idle screw, that can be accessed via the Inspection Panel?

So, after reviewing the "Draft" drawings of the Center Spar, I'll give ZAC an A+ for engineering a solution that required no solution. I would expect the Center Spar delivered with new Kits to be different, not better, due to manufacturing efficiencies.

Comment by Greg P Couttie on December 5, 2009 at 7:33am

I believe that going forward Zenair will be making the center section "completely "out of 0.063" .just a thought but can you provide a complete set of new webs for us instead of "patching over" the old ones ,this will allow full coverage of 0.063" across all SIX holes .If we have to strip out the 4 center spar caps ,all you have to do is (cut the top and bottom flanges and the lightening flange lip off of the old 0.032" webs ) allowing us to lay it FLAT -AS A TEMPLATE on top of the NEW ones, BACK DRILL all the RIVET HOLES ONLY re-attach the spar caps to the NEW webs with clecos then MATCH DRILL the twelve wing attach holes to the new spars. This would obviously require some very carefull thought to ensure alignment but would result in a much stronger and nicer job .this also gives us CLEAN FLANGES with no holes drilled in them allowing a better fit onto the existing holes in the floor,we would also end up with a spar that is 0.064" narrower as you are not overlapping the old webs.
Greg

Comment by Greg P Couttie on December 5, 2009 at 6:50am

I have two questions regarding the photographs above...
1.The( 4 ) 0.063" doublers you are adding dont match your drawings ,the drawing show them stopping "short" against the wing attachment uprights ,your pics show them as full length (span)of the spar .
2. I do not like the way the new doublers (do not cover the spar caps fully)as again your drawing shows otherwise ,in the above photographs the new doublers " look to short" with the rivet holes rather close to the edge .
Greg