Q&A - Zodiac 601XL -650 for the latest upgrade drawings of November 24 2009

This Q&A is for the upgrade kit of the Zodiac 601XL & 650 based on drawings of Nov. 24, 2009 and AMD Safety Alert of November 7. 2009

New drawings:
Nov. 24, 2009: We've updated the draft Drawings 6-ZU-1, 6-ZU-2, 6-ZU-3 and 6-ZU-4, and LAA Aileron Balance.

For very detailed questions (or if you must complain or vent), email me at newplane@gmail.com

Please post all your questions on the last page.

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Replies to This Discussion

I can only believe what I've been told by Allan, whom I have no reason to doubt.
Some builders in Oz have paid extra to have their kits air-freighted and even they, I am told, have not received deliveries.
I am sure you should be able to confirm or deny the existence of any order from OZ. Please check and let me know as I would have no hesitation in dealing with any problem this end. I think based on my comments you should be on the phone to Allan since you are casting doubt on whether Allan has in fact ordered kits. Zenair Australia is our representative here. There's no point individuals ordering outside the dealer process. That's what he's there for.

Paul Toone

Zenair Australia has ordered 36 kits in mid Dec 09 from Zenith Aircraft Company USA
Please note Paul, Mathieu works at Zenair in Canada so he may not be aware of all things happening at Zenith USA. At the end of Dec all Aussies' who had ordered kits had the option to have their kits sent by air or sea freight your chose was sea freight. I have been chasing these kits constantly with the Zenith but you must remember that there are over 1500 kits needed world wide, we are in line like the others people who have ordered mod kits. I have not tried to send out info that would give Aussie builders false hopes as to when the kits would arrive. Once I have set dates for shipping, I will inform all the Aussie's who have ordered kits of the facts not rumours. The latest info I have been told is the final parts for the 13 (airfreight) kits have been sent on Thursday last week. The crate for the sea freight has been ordered and once that arrives at Zenith USA the kits will be shipped, I have already set in motion arrangement for the shipping to Aust. I was waiting for emails to confirm this information as thing can go wrong with the best plans. I say again, once I have the facts I will let you know .
I hope this clears up you questions

The FAA and NTSB have a problem with flutter. That's why all of this is going on. If I were going to pick just one mod to do to my Zodiac, it would be the mass balance. Even with all of this structural strengthening, if for some reason your ailerons started vibrating out of control, your wings are still going to fail. Just because most of us have not experienced this before, it could be caused at anytime by any of us, unintentionally, during an emergency maneuver. The balance will dampen the flutter. The big hole in the rear spar way out there on the end of the wing is practically inconsequential.
I'd suggest caution in abandoning the LAA mass balance design, Steve. At the very least, you should verify that any new design meets established criteria including the attachment criteria in A&E Report No. 45 or MIL-F-25352. Your new design may be compliant. However, if you do not know for sure, I would suggest that you might want to run your design past a DER who specializes in flutter analysis.
I think you've made the best choice, Steve. Good luck with your upgrade.
I received my upgrade kit and am looking it over preparing to begin putting the plane back together tomorrow. I have a 601XL TD and there are some differences in the fuselage between tri-gear and TD that aren't addressed in the instructions.

1) Drawing 6-ZU-3 has a "Side Doubler", 6-ZU-3-2. The shape and location of this doubler appears to be more to strengthen the main gear attachment than the wing spar carry through. The 125mm side is next to the gear attach at the rear and the 40mm side is next to the spar at the front. Is this piece necessary on the TD which has no gear in the location shown? Should this doubler be made similarly, but turned around so the tall side is next to the spar?

2) Drawing 6-ZU-3 shows an added "Z" angle reinforcement between the lower front edge of the spar and the fuselage top longeron at the next forward vertical angle. This area is where the TD main gear attaches and there are two 0.75" OD 4130 steel tubes approx 220mm apart, 6-TD-3-1, riveted to the skin extending from the bottom up to the top longeron. My question is whether the "Z" angle is still needed here. There will be about 50mm space between the top of Front Wing Upright 6-ZU-2-6 and the landing gear tube so the Z would fit, but seems superfluous.
Good questions for the TD.
1, 6-ZU-3-2. Install as per the upgrade drawings. The bracket is for re-enforcing the skin in that area, in +g loads.
2, Yes, the "Z" angle is still needed but the exact location is not important. Like 6-ZU-3-2, it re-enforcing the skin in that area, in +g loads.
A lot of loads are transfered from the spar to the fuselage side skins front and rear in high +g loads. Both parts minimize bucking in the skins.

When we completed the static load tests which exceeded ultimate load, we noticed that there were certain areas that were getting some deformation. By adding a few simple angles, the deformation disappeared. People keep asking why we are making the aircraft stronger. The answer is that there is a good possibility that some of the accidents may be due to overloading of the airframes (as stated in many of the NTSB reports).
Thanks for the clarification.
I dont want to do all this work and later be told I have to pull the skin back again and add mass balances

The aileron mass balance is part of the upgrade and is included in the kit. The mass balance balance is not optional. Zenith wants us to install them.

Ken Pavlou
Greetings Mathieu,

I am wondering about drilling a hole large enough to accommodate a socket used in conjunction with a torque wrench in the upper left corner of the left front seat panel and the upper right corner of the right hand seat panel -- how this would affect the structural integrity. It would make torquing the wing bolt/nuts easier when attaching wing spars to the main spar!
If this is a doable modification can you offer a recommendation on how it should be done?

I want to thank you and your staff for all that you have done in engineering, producing and supplying a retrofit kit that puts my mind at ease.

Mack, the poh-ol-unemployed farm boy from Idaho
Dang, just use the wrench on the other side?


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