Replies to This Discussion

Permalink Reply by Jim Snyder on November 15, 2009 at 11:57am

Thanks. I guess I missed it in my first scan. I found it on Page 3.

Sorry.

Jim Snyder

Permalink Reply by Matt Heintz on November 15, 2009 at 1:49pm

Good point Jake,
Yes, we intent to add this Q&A to the original Q&A. However, once we will have the next revision drawings, I think that a lot of the questions will be automatically answered.

Permalink Reply by Chris Sinfield on November 15, 2009 at 2:37pm

Mathieu
Ok for those of us wondering
Why was the front extrusion angle 6-zu-1-1 only 1680 long? and not the full length? full length would be stronger as it now has a flexpoint midway along the spar and anyway the leading edges are fully open. Was it was for shipping of the kits? lightness of the wing or just not required.?

also if we can get the top rear spar angle 6-ZU-1-3 as full length, then is the overlap still req?

Chris

Permalink Reply by Matt Heintz on November 16, 2009 at 7:39am

Without the wing lockers / extra range tanks, the extrusion does not have to be as long as it is right now. However, in order to make sure that everyone is getting the proper length, its easier to set it at 1680. Why not longer? It just is not needed as most of the wing loads are at the root area and not at the tip. The flex point is not an issue as the top spar cap angle 6W-3-6 was not designed to be part of the spar cap loads. This is why the load tests passed with no hint of any deformation exceeding ultimate load by more than 6%.

Permalink Reply by Jerold Ebke on November 15, 2009 at 3:58pm

Mathieu, If I missed this earlier, my apology. I have 650 wings completed and on holding cradle. I have wing lockers installed and am happy your father says lockers are OK. How will we address placement of locker lid hinge with the larger angle which now interferes with where the hinge pin sits in relation to the spar since the pin is turned down and cannot assume its previous position with the new and wider angle? Thank you . Sincerely, Jerold Ebke

Permalink Reply by Matt Heintz on November 16, 2009 at 7:41am

The wing locker hinge will have to be riveted to the new "L" extrusion with spacer under it as to simulate the rear top skin in the area.

Permalink Reply by John Partridge on November 15, 2009 at 5:53pm

Hi Mathieu,

I'm probably getting a bit ahead of things, but regarding the mass balancing of the ailerons: If the German research concluded beyond doubt that flutter did not exist on the 601xl, why are the mass balance mods required. I understand the structural mods, no problem but I'd like to only have to do the work that is required to meet the FAA requirements. Is the mass balancing required by the FAA?
Thanks again to you and your brother for the detailed information. It is very much appreciated.
Regards,

John Partridge

Permalink Reply by Matt Heintz on November 16, 2009 at 7:44am

I hope that Zenith will be doing this this week and adding the photos to the blog. Supplying an extra piece of 0.063 to the kit is not a problem for those people who have the wing jig (simulating the outer wing spar at the root).

Permalink Reply by Tim Juhl on November 15, 2009 at 7:01pm

Mathieu,
Much credit goes to you and your family for sticking by the Zodiac builder and flyer community throughout all the controversy that followed the tragic breakup of several aircraft. I appreciate that you just didn't "walk away" and leave us all to work out a solution on our own. It cannot have been easy for you and I just want you to know that I appreciate the way that you have dealt with the problem.

I received my XL kit in 2006 and finished the tail surfaces, flaps and ailerons, wings and part of the fuselage before suspending construction in April 2008 to see how the concerns over the aircraft's structural integrity was going to play out. I am looking forward to receiving the mod kit and getting back to work!

The XL kit has evolved a bit since I got mine and of course you came out with the 650. I hope that your kit and instructions will address the various differences between earlier and later versions of the aircraft. To do so I believe it will require a basic mod kit and options for those who have additional issues to address. I would ask that you:

1.) Be sure to address how the mods affect those of us who chose to install wing lockers.
2.) If the kit does not include sufficient rivets to replace all those that will need to be drilled out to gain access to the underlying structures it would be helpful if you could provide guidance on how many are needed for each component to save us each from having to go out and count them one by one.
3.) Any special guidance you have on how to drill out the solid rivets in the spar without damaging it will be appreciated. It would be nice to have a little tool (like a steel block machined to fit over the head of the rivet) that would make sure the drill bit went where it is supposed to.
4.) Provide information on any special tools (clecos, clamps, etc.) that were not required for the original kit that will be needed to do the modification.
5.) Option: Allow for attachment of the upper spar angle with rivets or bolts and allow the kit to be ordered either way. A short pro vs con discussion on the merits / problems of each fastener might help in the decision making process.
6.) Option: For those of us who originally chose to go with hingeless ailerons provide a kit and instructions that will allow us to convert the existing ailerons to hinge type if required.
7.) Option: For those of us who are supposed to use a Wing Jig to set the positions of the front and rear spar fuselage attachments provide modification instructions and parts for the jig so it matches the new wing dimensions if needed.
8.) Option: For those of us with the XL wing, you should make a determination as to whether the L angles added to the 650 wing to prevent "oil canning" should be added and provide parts and instructions as an option.
9.) When preparing your instructions it might be a good time to summarize some of the earlier suggested mods (elevator stop - aileron gussets & etc.) so that all needed changes are accomplished at one time.

I'm sure much of this has been covered by others but I just wanted to share my concerns.
Tim Juhl

Permalink Reply by Matt Heintz on November 16, 2009 at 8:19am

Tim,
Good points. Zenith is upgrading their demo aircraft right now which is one of the oldest 601XL's. Their blog on this site is proving to be very effective, so I am confident that everyone doing the upgrade will not have any problems if following the drawings (to be updated) and the blog.
1, For those of you who have wing lockers, we hope to add something to the drawings on this.
2, The kit will include all the rivets and hardware needed. If you think you need anything extra, make sure you let Zenith know before they ship your upgrade kit. If you will be bolting the new extrusion, let them know so that you do not get the solid rivets.
3, Yes, see the Zenith blog and AC 43-13.
4, If you follow the details of the upgrade on the Zenith blog, I think that it will give you a good idea of what you will need. If you do not have a solid rivet gun, you do have the option of installing bolts.
5, The only reason why you may want to install bolts instead of the solid rivets would be - you do not have a solid rivet guy - you cannot do the riveting properly - the rivet hole diameters are too big.
6, There is nothing wrong with the hingeless ailerons and we do not recommend changing them to the hinge system. However, this has been addressed in an earlier Q&A. To change to the hinges, add an "L" angle to the aileron so that the hinge is sandwiched between the "L" angle and the aileron skin.
7, There is no need of the wing jig. Fitting the wing to the fuselage is just fine. The wing jig is just a spacer representing the wing root cap thickness that slides into the centre spar. It can be made out of wood, aluminum etc.
8, The "L" angles on the top skin (parallel to the spar and between the front and rear spar) will be added to the upgrade drawings. They are easy to install and since the wing is already open, its a good idea to install them. And yes, they do a great job to prevent "oil canning"
9, When doing the upgrade, you still need to follow all the points in the 41 page inspection list. We also strongly recommend that you download the AMD Service Manual as there are some good check lists in that. Same goes for the POH.

Permalink Reply by Gary Ray on November 15, 2009 at 8:29pm

I have a 601XL. Is it possible during the upgrade to set the angle of incidence of the main wing so as to match
the 650? This would resut in a lower deck angle and improved forward visibility.

Permalink Reply by Matt Heintz on November 16, 2009 at 8:23am

Yes, you can do this but you are adding a lot of extra work as you will have to change the fuselage side skins, your seats and arm rest area etc. We really did not see much change in performance or visibility with the new angle. Big reason for changing was to make the European and USA 601XL more the same as it makes it a lot easier for us to build and ship similar items. If you want to do this, you will need to purchase the 650 drawings.

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