Magnum spinners, just curious but.......
09-06-2003, 04:07 PM
#1
Magnum spinners, just curious but.......
How many of you have had your spinner part company in the air on your magnums?
I was flying a couple weekends back and the engine was running great! come by on a low pass.......
whhhhheeeeeeeeeeeeeeeeeeeeeeeeeeee ZING!!!! pop..... whhhhhhhhheeeeeeeeeeeeeeeeeeeeee
at first I thought I'd lost a prop blade but it was still running fine. Then I saw no spinner anymore, so I landed. We did find the spinner, it was literally splayed out near flat and the bolt was sheared at the nut. I first thought it must have loosened and came off, but the little lip that fits in the backplate was gone on the cone. My best guess is that the bolt loosened enough to allow the spinner to shake just a bit, sheared off that bit of aluminum, spun it outwards snapping the bolt. The weird part is, it didn't mark the prop at all, but it did scrape the anodized purple thrust washer
Anyway, I have a new spinner now, but I think I'm gonna retap the prop nut for an SAE spinner bolt and use a higher grade bolt. I always checked it for tightness, and I dont' think I ever over tightened it, but man, don't wanna go through that again!
I was flying a couple weekends back and the engine was running great! come by on a low pass.......
whhhhheeeeeeeeeeeeeeeeeeeeeeeeeeee ZING!!!! pop..... whhhhhhhhheeeeeeeeeeeeeeeeeeeeee
at first I thought I'd lost a prop blade but it was still running fine. Then I saw no spinner anymore, so I landed. We did find the spinner, it was literally splayed out near flat and the bolt was sheared at the nut. I first thought it must have loosened and came off, but the little lip that fits in the backplate was gone on the cone. My best guess is that the bolt loosened enough to allow the spinner to shake just a bit, sheared off that bit of aluminum, spun it outwards snapping the bolt. The weird part is, it didn't mark the prop at all, but it did scrape the anodized purple thrust washer
Anyway, I have a new spinner now, but I think I'm gonna retap the prop nut for an SAE spinner bolt and use a higher grade bolt. I always checked it for tightness, and I dont' think I ever over tightened it, but man, don't wanna go through that again!
09-08-2003, 06:09 PM
#3
Join Date: Dec 2002
Location: Kortessem, BELGIUM
Posts: 3,607
Likes: 0
Received 13 Likes
on
11 Posts
RE: Magnum spinners, just curious but.......
The center bolts supplied with the spinners are of the "chocolate" type...
The one I got with my plane was slightly too long also, so I had to replace it anyway and I put a good steel one in... it doesn't move one bit... it even survived when my Magnum nosed in due to a broken aileron servo and the spinner was destroyed...
Hard to believe actually that a company tries to save money on something as cheap (but important) as that bolt... I mean COME ON, how much is the price difference between a good steel bolt and a "chocolate" one...?
Don't forget to balance your spinners in high rpm applications.
And if you don't have a habit of breaking props you could also try putting a drop of CA where the spinner meets the backplate...
Tighten the center bolt until the spinner backplate just starts to deform... you can see it when you move the prop back and forth... then loosen about 1/8 turn... and set her free and let her rip
The one I got with my plane was slightly too long also, so I had to replace it anyway and I put a good steel one in... it doesn't move one bit... it even survived when my Magnum nosed in due to a broken aileron servo and the spinner was destroyed...
Hard to believe actually that a company tries to save money on something as cheap (but important) as that bolt... I mean COME ON, how much is the price difference between a good steel bolt and a "chocolate" one...?
Don't forget to balance your spinners in high rpm applications.
And if you don't have a habit of breaking props you could also try putting a drop of CA where the spinner meets the backplate...
Tighten the center bolt until the spinner backplate just starts to deform... you can see it when you move the prop back and forth... then loosen about 1/8 turn... and set her free and let her rip
