Pusher Prop New, but 30 mins later & ovaled out? *Help* What did that?
09-17-2009, 10:36 PM
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Pusher Prop New, but 30 mins later & ovaled out? *Help* What did that?
Help, any advise on this situation,
New APC 11x7P = pusher on my Bobcat 50 pudhrt with a NEW Super tiger .61 ABC.
Broke in the Engine on the plance, used 2 standard props the first 2 to 3 tanks, then used the pusher prop with another 1.5 tanks.
So I take off the prop to verify the direction of prop spin and how it was facing, because the fat edges was turning into the wind, counter clockwise, but my fellow members said that was normal... Soooooooooo what do I discover??
I discovered the BRAND new APC pushe is now loose on the shaft and ovaled to one side; WHAT the HECK?????
> How did a stick'in tight prop even move to get ovaled??? confused???
I used a fairly long 9/16" hand wrench to tight it on the new Great Planes 2-3/4" nylon spinner backing plate???
> Initially I had it bolted on without a spinner and took it off and I think it was fine??? could the nylon spinner backing plate be screwing it up???
-> could it be out of balance, I just borrowed a buddy's prop balancer(non-magnetic one) and will balance it for the first time(I have NEVER balanced a prop, although
I've only flown .15, .25 .40 & .46 engines, this is my first .61
*HELP*
Thanks in advance
P.S. Maiden flight is finally supposed to be tomorrow eve, weather break after 2 weeks, then club picnic sat, so I am scrambling on this last detail???
New APC 11x7P = pusher on my Bobcat 50 pudhrt with a NEW Super tiger .61 ABC.
Broke in the Engine on the plance, used 2 standard props the first 2 to 3 tanks, then used the pusher prop with another 1.5 tanks.
So I take off the prop to verify the direction of prop spin and how it was facing, because the fat edges was turning into the wind, counter clockwise, but my fellow members said that was normal... Soooooooooo what do I discover??
I discovered the BRAND new APC pushe is now loose on the shaft and ovaled to one side; WHAT the HECK?????
> How did a stick'in tight prop even move to get ovaled??? confused???
I used a fairly long 9/16" hand wrench to tight it on the new Great Planes 2-3/4" nylon spinner backing plate???
> Initially I had it bolted on without a spinner and took it off and I think it was fine??? could the nylon spinner backing plate be screwing it up???
-> could it be out of balance, I just borrowed a buddy's prop balancer(non-magnetic one) and will balance it for the first time(I have NEVER balanced a prop, although
I've only flown .15, .25 .40 & .46 engines, this is my first .61
*HELP*
Thanks in advance
P.S. Maiden flight is finally supposed to be tomorrow eve, weather break after 2 weeks, then club picnic sat, so I am scrambling on this last detail???
09-17-2009, 11:19 PM
#4
RE: Pusher Prop New, but 30 mins later & ovaled out? *Help* What did that?
If the hole in the prop is now ovaled throw it away and start with a new one. There is really only 2 things that could cause it to oval out:
1. It was seriously out of balance and loosened off the nut enough to allow it to rotate off center
2. The hole was to big to begin with and the prop was off center causing the prop to rotate off center which then perpetuated the vibration and back to cause #1
You have to balance props if you want success. Balance the spinners too, they are usually ok, but they can be off, I personally hate any form of plastic spinner be it dubro, great planes, or otherwise. I have pretty much always stuck with Tru Turn spinners.
As for direction of the prop, since it is a pusher it does spin backwards obviously, but you still have to mount it with the front face of the prop towards the front of the airplane.
1. It was seriously out of balance and loosened off the nut enough to allow it to rotate off center
2. The hole was to big to begin with and the prop was off center causing the prop to rotate off center which then perpetuated the vibration and back to cause #1
You have to balance props if you want success. Balance the spinners too, they are usually ok, but they can be off, I personally hate any form of plastic spinner be it dubro, great planes, or otherwise. I have pretty much always stuck with Tru Turn spinners.
As for direction of the prop, since it is a pusher it does spin backwards obviously, but you still have to mount it with the front face of the prop towards the front of the airplane.
09-17-2009, 11:35 PM
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RE: Pusher Prop New, but 30 mins later & ovaled out? *Help* What did that?
Are you absolutely positive that the propeller was not oval before you started using it? Try another propeller and see if the same thing happens. You might get more response to this question if you posted it in the engines forum.
09-19-2009, 04:14 AM
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RE: Pusher Prop New, but 30 mins later & ovaled out? *Help* What did that?
10000% sure it was NOT ovaled b4 I started, it was new and I had to drill it.
I drilled the hole only after I used my digital venier calipers and made the hole just snug on the shaft. So i wallowed with that cheap GP nylon spinner, wasted a new apc prop...
I was tight, althout not balanced.
Great tips, I will check the prop squish sat late am...
Thanks
P.S. My fellow club member who flies 5 different jet types (from ducted to .91 nitro) took the first attempted maiden flight of my Bobcat.... BUT, about 20 feet off of take off and the engine shutoff, crap.... so she came in for a fairly good landing at fast high AOA landing and bent the landing gear and broke one of those cheap THIN china plastic screws. So, I am frustrated that it shut down, what the heck????
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I drilled the hole only after I used my digital venier calipers and made the hole just snug on the shaft. So i wallowed with that cheap GP nylon spinner, wasted a new apc prop...
I was tight, althout not balanced.
Great tips, I will check the prop squish sat late am...
Thanks
P.S. My fellow club member who flies 5 different jet types (from ducted to .91 nitro) took the first attempted maiden flight of my Bobcat.... BUT, about 20 feet off of take off and the engine shutoff, crap.... so she came in for a fairly good landing at fast high AOA landing and bent the landing gear and broke one of those cheap THIN china plastic screws. So, I am frustrated that it shut down, what the heck????
Hide Signatures
