golden bee running issue

mitchg95 Thu Jul 12, 2012 10:48 pm

hello, i have had a problem with my golden bee today.
It ran perfectly with one of Bernie's yellow safety props and gave no fits, and as i posted in another topic. I want to turn this engine into a mouse racing engine, and am doing so one step at a time
the things i used today was a apc 4.75x4 1/2a pylon prop with power master 30% nitro fuel and 20% oil.
the problem that i encountered to day is that the engine likes to "surge" at a certain nv setting, but if i lean out the engine when it is surging the problem goes away
also when the engine is surging it seems to have way more vibration as the engine seems to move back and forth about 1/4'' in every direction
what may cause this? im thinking a unbalanced prop may be contributing to this as the engine did not do this with the other prop
and also, i do not have a tach, so could someone tell me from previous experiance what a cox .049 will do rpm wise with a #6 cyl and piston, 30% nitro and a 4.75x4'' prop
thanks, the next mod i want todo with the engine is going to be, swapping out the #6 cylinder, with a #1 black widow cylinder and piston

many thanks in advance, MitchG95

happydad Thu Jul 12, 2012 11:43 pm

mitchg95 wrote:hello, i have had a problem with my golden bee today.
It ran perfectly with one of Bernie's yellow safety props and gave no fits, and as i posted in another topic. I want to turn this engine into a mouse racing engine, and am doing so one step at a time
the things i used today was a apc 4.75x4 1/2a pylon prop with power master 30% nitro fuel and 20% oil.
the problem that i encountered to day is that the engine likes to "surge" at a certain nv setting, but if i lean out the engine when it is surging the problem goes away
also when the engine is surging it seems to have way more vibration as the engine seems to move back and forth about 1/4'' in every direction
what may cause this? im thinking a unbalanced prop may be contributing to this as the engine did not do this with the other prop
and also, i do not have a tach, so could someone tell me from previous experiance what a cox .049 will do rpm wise with a #6 cyl and piston, 30% nitro and a 4.75x4'' prop
thanks, the next mod i want todo with the engine is going to be, swapping out the #6 cylinder, with a #1 black widow cylinder and piston

many thanks in advance, MitchG95

mitch: did you try another prop of similar size after the vibration? i think you are right about an out of balance prop. happydad. Small Cox Logo

microflitedude Fri Jul 13, 2012 9:02 am

I had the same issue with my Killer Bee. The threads in the crankshaft were offset, causing to vibrate badly. Once it peaked out, it stopped. Are you using a Killer crank? Swap out the prop screw too, that can do it. Most likely the prop as HD said.

You need a better mount if the engine can move 1/4".

EXModelEngines Fri Jul 13, 2012 10:11 am

Mitch,

The APC props are notorious for having vibration issues out of the box. Best thing to do is balance them, including blades and hub (they have had a habit of drilling the hubs off-center lately).

Regards, Matt

mitchg95 Fri Jul 13, 2012 10:42 am

microflitedude wrote:I had the same issue with my Killer Bee. The threads in the crankshaft were offset, causing to vibrate badly. Once it peaked out, it stopped. Are you using a Killer crank? Swap out the prop screw too, that can do it. Most likely the prop as HD said.

You need a better mount if the engine can move 1/4".

i have no killer bee crank or the tool to do so, so i am using the stock babe bee crankshaft, i balanced the prop last night and is perfect Smile

i also made a new motortest stand on a 1x6'' hard wood with 1/4'' ply held in with 4 thick wood screws
ill test it again today and see if the problem is gone

does anyone have a used kb shaft that i can use?

microflitedude Fri Jul 13, 2012 11:15 am

mitchg95 wrote:does anyone have a used kb shaft that i can use?

I've got 4 of them, and 3 of those are screwed up. I just traded my last good spare to Ron.

mitchg95 Fri Jul 13, 2012 11:16 am

microflitedude wrote:
mitchg95 wrote:does anyone have a used kb shaft that i can use?

I've got 4 of them, and 3 of those are screwed up. I just traded my last good spare to Ron.

dang, whats whats wrong with em'?

microflitedude Fri Jul 13, 2012 11:17 am

mitchg95 wrote:
microflitedude wrote:
mitchg95 wrote:does anyone have a used kb shaft that i can use?

I've got 4 of them, and 3 of those are screwed up. I just traded my last good spare to Ron.

dang, whats whats wrong with em'?

2 have the threads offset, and the other has oversized splines so that you can't install the drive plate.

mitchg95 Fri Jul 13, 2012 11:18 am

microflitedude wrote:
mitchg95 wrote:
microflitedude wrote:
mitchg95 wrote:does anyone have a used kb shaft that i can use?

I've got 4 of them, and 3 of those are screwed up. I just traded my last good spare to Ron.

dang, whats whats wrong with em'?

2 have the threads offset, and the other has oversized splines so that you can't install the drive plate.

dang, thanks man.
love the avatar lol

mitchg95 Sat Jul 14, 2012 3:02 pm

i got the golden bee running perfect yesterday. the unbalanced prop is the culprit, so i have all my 1/2a props balanced and ready togo now Smile

thanks

Godsey3.0 Sat Jul 14, 2012 3:12 pm

I remember having and issue like this. The engine would rev up and down real bad. If it was dark enough you could see the red in the ports getting brighter and dimmer. The prop would have a wave appear in it as well. I believe it was a Yellow prop. I just switched props and problem was solved.

mitchg95 Sat Jul 14, 2012 3:14 pm

Godsey3.0 wrote:I remember having and issue like this. The engine would rev up and down real bad. If it was dark enough you could see the red in the ports getting brighter and dimmer. The prop would have a wave appear in it as well. I believe it was a Yellow prop. I just switched props and problem was solved.

i noticed the prop flexing on my yellow prop to, it looks weird
ill get some pics of it running, maybe even a video Smile

**Cribbs74** Sat Jul 14, 2012 3:28 pm

Happy to hear you solved the problem Mitch, I guess you know now the difference an unbalanced prop makes.

mitchg95 Sat Jul 14, 2012 4:32 pm

having trouble with video's on camera, so here are a couple static photos of the engine after i had it running
balance propellers - golden bee running issue Sam_2013

balance propellers - golden bee running issue Sam_2013

balance propellers - golden bee running issue Sam_2014

stupid camera wont open the file that it made, jeez hopefully a video soon

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