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  #1  
Old 07-08-2019, 08:16 PM
PhatRV PhatRV is offline
 
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Default Slightly OT: Extra 330 with Horizontal Solenoid

I came across this video from Erik Johnson Youtube channel about the "conditional" inspection of an Extra 330. In this video, the solenoid is mounted horizontal because the high Gs of this aircraft. Has anyone mounted his solenoid this way? Or any problem mounting the solenoid upside down and get it to trip flying inverted?

https://www.youtube.com/watch?v=XDLBpp2vaA0&t=113s

Jump to 50 seconds mark.
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Last edited by PhatRV : 07-09-2019 at 11:24 AM. Reason: Fixed Link
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  #2  
Old 07-08-2019, 09:19 PM
Mich48041 Mich48041 is offline
 
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If a contactor has a drain hole, it should be at the bottom to prevent water from accumulating inside of the case.
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  #3  
Old 07-08-2019, 09:43 PM
rv7charlie rv7charlie is offline
 
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First, listen to Joe. Next, explore need. Weigh the moving parts in a solenoid, and multiply by 10 (or 15, if you want headroom for for an Extra). Now, measure the force needed to collapse the return spring in the contactor. Is it less than, or greater than the 15G weight of the moving parts?

I'm always impressed at the myth & metaphysics in aviation....

;-)
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  #4  
Old 07-08-2019, 10:57 PM
PhatRV PhatRV is offline
 
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I read the solenoid is mounted upside down to prevent inadvertent start of the engine in high +G maneuver. I can't recall where I read it, aeroelectric or Marc Ausman's book. I don't have my hand on a solenoid yet, not for at least a year from now when I will be ordering the finishing kit, so I can't tell how strong the spring/mass, etc.

This whole experimental thing is about learning and doing so I guess I better ask rather than stay ignorant. Knowing the pilot in video pulls some serious Gs in his demo routine so I guess it's a good idea to listen to what he has to say, I suppose. But dang, must all answers in VAF come across like admonishments.

Anyway, thanks for the information.
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  #5  
Old 07-08-2019, 11:21 PM
rv7charlie rv7charlie is offline
 
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I sincerely apologise. I promise that my flippant remark wasn't intended to put you down, or directed at you, at all. I was referring to how unsubstantiated stuff gets passed forward, as it apparently was to you (and likely the Extra guy, since his contactor is sideways), and it gets acted on without test or verification. A couple more are the 'no oversquare' and 'no lean of peak' rules, which have existed for decades and are only slowly being tamped down by actual evidence.

We all learn by asking; I was just trying to say we should verify new knowledge.

BTW, the Aeroelectric list was where I first saw the contactor thing challenged.

Again, sorry for my poor choice of words.

Charlie
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  #6  
Old 07-09-2019, 08:10 AM
PhatRV PhatRV is offline
 
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Thanks for the aeroelectric reference. I need to review the material from its website again.
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  #7  
Old 07-09-2019, 09:05 AM
rv7charlie rv7charlie is offline
 
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One reference to the start contactor issue is at the end of chapter 11 in AEC v.12A. He does mention horizontal motion (fore/aft) of the start contactor that's sold by B&C ( https://bandc.com/product/intermitte...ter-contactor/ ), but I suspect that's more a byproduct of mounting it on the firewall. Many a/c would have the same type contactor mounted on a tray.

If memory serves, my info was drawn from Nuckolls' more extensive writing about the subject on the AEC email list.

BTW, for some reason, when I click the link for the condition inspection video, youtube is taking me to a girl's music page.

Charlie
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  #8  
Old 07-09-2019, 09:30 AM
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DanH DanH is offline
 
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Quote:
Originally Posted by PhatRV View Post
But dang, must all answers in VAF come across like admonishments.
Perception based on cultural difference. In Mississippi, it's just an answer.
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  #9  
Old 07-09-2019, 10:48 AM
Mich48041 Mich48041 is offline
 
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I have hit bumps in turbulence that pulled more G force than any aerobatic maneuver. No contactors in the plane opened or closed.
Bob Nuckolls' POST about contactor orientation. His bottom line: "Maneuvering g-loads in airplanes you and I like to fly are not a risk to your various contactors."
Listen to Charlie.
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  #10  
Old 07-09-2019, 11:25 AM
PhatRV PhatRV is offline
 
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Quote:
Originally Posted by rv7charlie View Post
BTW, for some reason, when I click the link for the condition inspection video, youtube is taking me to a girl's music page.

Charlie
Link is fixed.

Some more research led me to an EAA video about the starter solenoid.

https://www.eaa.org/Videos/1198141598001

He did mention the aerobatic guys mount their starter solenoid in the horizontal position so I think is the common practice this that world.
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Last edited by PhatRV : 07-09-2019 at 11:28 AM.
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