Replies to This Discussion

Permalink Reply by Alberto Martin on November 14, 2009 at 2:33am

Hello Michael,

I´m Alberto builder of an US ZAC 601 XL serial 6-7011, and helping my friend Jorge with the building of his XL serial 6-7036, both are located in Barcelona, Spain

The question is about two other friends of mine and theirs CZAW 601 XL UL version and the FAA upgrade.

Does a CZAW 601 have to comply to this upgrade? . One is a QB that has flown 400+ hs, and the other one is at 85% of completion with wings and fuselage ready.

Please, let us know, Thanks in advance,

Permalink Reply by Matt Heintz on November 14, 2009 at 7:19am

Chris Heintz will be issuing a similar upgrade but less extensive for the European Micrlights at 450-470kg in the very near future. For the Experimental / home-built version at 600 kg, same upgrade is required.
We understand that it is frustrating for an owner to upgrade his/here aircraft especially with +400 hours of trouble free flying. However, to be on the safe side, it is better that we all upgrade.

Permalink Reply by Julio Cuenca Soria on November 14, 2009 at 4:50am

Hola Mathieu.
Estoy terminando la construcion de mi zodiac 601 xl . CZAW . ¿deberia instalar el kit de actualizacion? .
En caso afirmativo ¿ Donde y como podria pedirlo?.
Gracias de antemano.
Saludos.
Julio.

Permalink Reply by Matt Heintz on November 14, 2009 at 7:24am

In English, I believe that this translates (google translation) to:

Hi Mathieu.
I'm finishing the construction of my zodiac 601 XL. CZAW. Should I put the upgrade kit? .
If so, where and how to ask?.
Thanks in advance.
Greetings.
July.

You will be able to purchase the upgrade kit from Zenair Europe.
http://www.zenairulm.com/Home/index.htm
We will have more information on this at the above Zenair Europe web site shortly.

Permalink Reply by Alan Uhr on November 14, 2009 at 7:32am

Mathieu,
On many vehicles made in this country, the structors are bonded together with a special tape. I have also seen rotorblades bonded this way on their trailing edges. That said, instead of drilling out the solid rivets on tha main spar, could the angle be match drilled where the rivets are so the angle just fits flush with the spar and then bonded with this special bonding tape. It would eliminate the drilling out of all solid rivets.
Alan Sorry for the double post.

Permalink Reply by Matt Heintz on November 14, 2009 at 7:37am

Interesting concept. However, we did not do our structural load tests with this bonding system, so I cannot recommend it. See the Zenith video on how they removed their solid rivets. It does take a bit of time, but there are not that many.
http://www.zenith.aero/profiles/blogs/part-3-installing-the-upgrade

Permalink Reply by Matt Heintz on November 14, 2009 at 4:17pm

Your existing part 6W7-2 does not get removed. 6W7-3 gets replaced with 6-ZU1-5.

Permalink Reply by Mark Hubelbank on November 14, 2009 at 4:42pm

Although I agree with many that the original design was good, I am doing the upgrade and appreciate the detailed support.

While we are doing this, is it a good time to use better bolts on the wing attachment? They appeared to be the only thing that failed at ultimate load. My calculations are that using high strength bolts, hardened washers, or even better a strip of steel and then higher torque would increase the clamping force and take some of the load off the sides of the bolts and holes. Even if it only increased the point of "damage" by 1 G, it seems worth it.

I still wonder if these aircraft need all the elevator and rudder control they have. Perhaps they still have too much.

Permalink Reply by Matt Heintz on November 15, 2009 at 11:39am

We passed and exceeded the ultimate by about 6% without the bolts failing. The same bolts were used for other tests, so I am not sure how perfect they were before the last test. Note that the LSA load requirements are significantly higher than typical FAR 23, to what the original 601XL was designed for. I would stick to the original bolts as harder bolts could create new problems.

Regarding elevator/rudder deflections, 99% of the time, you do not need that much deflection. Its when you are doing very slow flying that you may need it.

Chris likes to design his aircraft with lots of control at low speeds, but when flying fast, over controlling is possible. This is why its important to understand Va and Vc and to have a good calibrated and well marked ASI.

Permalink Reply by Matt Heintz on November 15, 2009 at 11:41am

In the upgrade, we are adding 0.063 to the spar bolt area, which will increase the structure around the bolts.

Permalink Reply by Matt Heintz on November 15, 2009 at 11:43am

Absolutely and very good idea. Add 0.063 to the jig as to represent the total width of the spar cap area, top and bottom.

Permalink Reply by Jim Snyder on November 15, 2009 at 8:51am

There is a lot of talk about light stick forces, especially pitch control. I thought I saw early-on that springs would be added to increase stick forces. Are these part of the upgrade kit, and if not, why not? If they are not part of the kit, can someone advise as to where and how they could be installed? I was considering doing this even before all the problems arose. I fly a Cherokee, and don't like twitchy controls.

Jim Snyder

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