Bendix Dual Mags

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ScottS
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Bendix Dual Mags

Post by ScottS »

In speaking with an AME friend the other day about aircraft purchase options, he was regaling me with horror stories of a simple 500 hour service of a Bendix dual mag that turned into an expensive exercise due to the decreasing availability of parts and support to these mags and to stay away from engines that have them for this reason (particularly we had been looking at 177Bs, and in 1973 they started using the 0-360-A1F6D)

I have tried doing some searching on the interwebs but can't find any references to specific concerns for support of these mags compared to singles. It's common for folks of all stripes to have personal biases based on what they have experienced so I am just wondering if there are other similar or differing opinions or experience maintaining these dual mag engines in Canada.

Thanks!


Edit: hmmm, as soon as I post this, I guess I found my answer in Lycoming Service Letter L249. http://www.lycoming.com/sites/default/f ... gnetos.pdf

I must not have been using the right search terms!
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Choppermech1986
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Re: Bendix Dual Mags

Post by Choppermech1986 »

Have been using them for the past 8 years flying about 800hrs a year on average, have had a few moisture issues but that's more of an airframe issue on the type that we're running. We were told parts would an issue but we have some spare units and the most frequently replaced parts are common to the single magnetos as well.

We always replace the distributor gears at 500hrs, you don't want teeth from one gear taking out the other, think of it as cheap insurance. You want an AME who knows the type to adjust the internal timing, as they do go out of time and you can't just rotate it on the flange to adjust it like you can a single magneto, a bit of patience is key to get both sets of points skookum before you offer it up to the engine.

We treat them like the weak point that they are and properly maintained we've never had a complete (Left & Right) failure, touch wood.
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PilotDAR
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Re: Bendix Dual Mags

Post by PilotDAR »

I can't speak to cost or availability of repair parts for the dual mags, but operationally, they send shivers down my spine. I would choose not to own an aircraft so equipped. I do not know how these were ever approved, as in practicality, they do not meet the design requirement for ignition system independence. I used to fly a 182RG which had one. At the 500 hour inspection, the mag was found to have shed two gear teeth on the "main" gear. They work, but they are less independent in the case of failure than all other certified arrangements.
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Chris M
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Re: Bendix Dual Mags

Post by Chris M »

Choppermech1986 wrote:...a bit of patience is key to get both sets of points skookum before you offer it up to the engine.
Failure to chooch is a bad thing.
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Choppermech1986
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Re: Bendix Dual Mags

Post by Choppermech1986 »

DAR, what do you mean by "main" gear? The engine driven metal gear that turns the two plastic distributor gears? I've never heard of a metal gear failing on a magneto, do you have any photos by chance? I've had lots of Bendix magnetos shear the plastic distributor gear on Robinson helicopters (which have two magnetos), fortunately there is no risk of those gear teeth migrating across to the other gear and taking it out as there is with the single drive dual magneto.

Well maintained, a dual magneto is safer than a pair of neglected single magnetos.
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photofly
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Re: Bendix Dual Mags

Post by photofly »

Chris M wrote:
Choppermech1986 wrote:...a bit of patience is key to get both sets of points skookum before you offer it up to the engine.
Failure to chooch is a bad thing.
Don't we have to keep our sticks (or something) on the ice, too?
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Choppermech1986
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Re: Bendix Dual Mags

Post by Choppermech1986 »

Dicks in a vice! All hail the northern 200 pound gorilla.
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Chris M
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Re: Bendix Dual Mags

Post by Chris M »

Release the shmoo! AVE is probably the best YouTube channel I've come across. I use his angry/dancing pixies line to explain electrical things to people now.
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xsbank
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Re: Bendix Dual Mags

Post by xsbank »

Holy crap, where am I? How did I get here? Why are they talking like this? GET ME OUTTA HERE!
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Choppermech1986
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Re: Bendix Dual Mags

Post by Choppermech1986 »

xsbank, search for AvE on YouTube. You're welcome. Unless you hate swearing, in which case, go f*ck your hat :wink:
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7ECA
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Re: Bendix Dual Mags

Post by 7ECA »

xsbank wrote:Holy crap, where am I? How did I get here? Why are they talking like this? GET ME OUTTA HERE!
The AMEs have been sniffing AvGas and JetA again... :lol:
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xsbank
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Re: Bendix Dual Mags

Post by xsbank »

Ok, it was almost as bad as that hip hop site I got into with my fat fingers...

I do know what "...go fzck yourself..." means. Thanks, I needed that.

You realize if I try and get into YouTube I may never be seen again?

Best to you, 'geers! Don't pay any attention to a cheesy pilot!
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gwagen
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Re: Bendix Dual Mags

Post by gwagen »

AvE is definitely the best and his verbiage has permeated my vocabulary, I find myself using or wanting to use some of his terminology but no one else understands.

Focus you fack

Put your wiener in a Wilton

Electrichicken

Electron plumber

Fabricobbled

Stick it in there, but just the tip mind you and only for a minute.

Gentleman welcome back to the wife's sewing room

Corpo shill vids......go fack your hat.....

Skookum bearing.......glass fibre reinforced.....
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photofly
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Re: Bendix Dual Mags

Post by photofly »

DeWilt
Milfuckee

I'm particularly fond of Canadian Pesos.
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all_ramped_up
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Re: Bendix Dual Mags

Post by all_ramped_up »

"Good enough for the Girls I go out with..." :lol:
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plhought
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Re: Bendix Dual Mags

Post by plhought »

I'm so glad I'm not the only aviation guy watching AvE!

In fact, the more I watch the more I'm convinced he's an AME or perhaps works in the mines or something.

He should be giving mini-lectures at the next symposium.
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