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don.honabach(at)pcperfect
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 Posted: Mon Aug 15, 2011 5:32 pm Post subject: Update! - 601 owners... something to watch for - engine mou |
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Thanks for sharing this!!
Don
Do Not Archive
From: owner-zenith-list-server(at)matronics.com [mailto:owner-zenith-list-server(at)matronics.com] On Behalf Of Michel Therrien
Sent: Monday, August 15, 2011 5:55 PM
To: zenith-list(at)matronics.com
Subject: Re: Zenith-List: Update! - 601 owners... something to watch for - engine mount fittings
Hello Group!
Attached are pictures of my two upper fittings. There is a crack next to the weld on the right fitting. There is one long crack that follow the weld and then curves around the bottom on the other fitting. There is also another horizontal crack starting from the bolt to the left side.
I got a response from Zenith Aircraft. They state that I am the only one that they are aware this happened. I learned today that one of my friend had a similar issue years ago. I also found an email about this in the 2004 archive of this list. The fittings are design to support engines of up to 300 lbs according to the response I got. I intend to make them using thicker 4130. I will also verify with my welder why there are cracks next to the welds.
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Michel Therrien CH601-HD, C-GZGQ
http://mthobby.pcperfect.com/ch601
http://pages.infinit.net/mthobby
From: Michel Therrien <mtherr(at)yahoo.com>
To: "zenith-list(at)matronics.com" <zenith-list(at)matronics.com>
Sent: Sunday, August 14, 2011 9:31:21 PM
Subject: Zenith-List: Update! - 601 owners... something to watch for - engine mount fittings
Today, I cleaned up the firewall after I removed all remaining parts related with my Soob installation.
The upper left engine mount fitting is broken at the weld seam and also at the lower bend... the firewall side of that fitting was no longer attached to the rest of the fitting and therefore was not pulling on the longeron at all. It was only pulling on the firewall.
The upper right fitting is broken on the side weld joint.
I tried to see if I could easilly see that upon inspection... not really easy. I was able to see the right fitting defect by playing with the bolt (the engine mount is removed). Otherwise, I dont really see that it is broken if I don't move it.
The lower fittings appear to be OK.. I will remove them for inspection however.
I will make new parts and I am considering using 0.080" 4130 instead of 0.050". I intend to paint them in yellow to ease seeing cracks. Right now, they are black. I'm a bit nervous putting a still heavier engine that will pull more HP on that frame... (my Franklin), but I know people installed O-235 and O-200.
I will contact Zenith Aircraft. Larry's explanation may be very much right.... the Soob installation is about 100 lbs heavier than a Rotax install. I cannot say that the Soob is a vibrating engine however, mine was very smooth.
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Michel Therrien CH601-HD, C-GZGQ
http://mthobby.pcperfect.com/ch601
http://pages.infinit.net/mthobby
From: Larry McFarland <larry(at)macsmachine.com>
To: zenith-list(at)matronics.com
Sent: Sunday, August 14, 2011 10:27:12 AM
Subject: RE: [Probable Spam] Zenith-List: 601 owners... something to watch for - engine mount fittings
Hi Michel,
I’m not surprised that that part failed. It was a very delicate construction from the beginning. This part was probably designed when the 601 was powered by lighter engines. The Subaru has some heft to it. I inspect this piece every year at the apex of the bend from both sides. Much harder to do with the solid cover. It’s not a bad idea to make the cover removable. Several years ago a Brit that flew from an old military airfield sent pictures showing both broken pieces and the firewall was doing most of the work before it was repaired. Good piece to add to the Annual
Inspection routine. Thanks for the heads up!
Larry McFarland 601HDS at www.macsmachine.com
From: owner-zenith-list-server(at)matronics.com [mailto:owner-zenith-list-server(at)matronics.com] On Behalf Of Michel Therrien
Sent: Saturday, August 13, 2011 10:25 PM
To: zenith-list(at)matronics.com
Subject: [Probable Spam] Zenith-List: 601 owners... something to watch for - engine mount fittings
Hi group!
I had a major unpleasant surprise today when I dismantled my firewall-forward installation. While removing the engine mount, I felt there was too much "play" in the movement of an upper engine mount fitting bolt. This is part 6-F-7-2 in the plans.
My upper left fitting was indeed cracked in such a way that the side angle was no longer united to the front side of the fitting. There might be more and I will know later when I remove the four fittings to inspect, sand blast and repaint them. At first glance, the lower fittings appear OK.
These are parts I never really inspected when I did my annuals so I don't know if I have been flying with broken engine mount fittings or not and for how long. But I don't like the idea that I did.
----------------------------
Michel Therrien CH601-HD, C-GZGQ
http://mthobby.pcperfect.com/ch601
http://pages.infinit.net/mthobby
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carlossa52(at)gmail.com
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| Posted: Mon Aug 15, 2011 7:19 pm Post subject: Update! - 601 owners... something to watch for - engine mou |
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Hello, Michel
I remember Larry M made these fittings differently, exactly because he thought this could happen.
This was years ago, but I am sure it's in the archives, and more than likely, in Larry's construction log.
Salut!
Carlos
On 15 August 2011 20:55, Michel Therrien <mtherr(at)yahoo.com (mtherr(at)yahoo.com)> wrote:
[quote] Hello Group!
Attached are pictures of my two upper fittings. There is a crack next to the weld on the right fitting. There is one long crack that follow the weld and then curves around the bottom on the other fitting. There is also another horizontal crack starting from the bolt to the left side.
I got a response from Zenith Aircraft. They state that I am the only one that they are aware this happened. I learned today that one of my friend had a similar issue years ago. I also found an email about this in the 2004 archive of this list. The fittings are design to support engines of up to 300 lbs according to the response I got. I intend to make them using thicker 4130. I will also verify with my welder why there are cracks next to the welds.
[b]
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