APC props center hole

crankbndr Wed Jul 11, 2012 8:56 am

I just got some APC props and the holes are so off center I can see it just by eyeball.
What a piece of junk. I'll never get the hole centered.

andrew Wed Jul 11, 2012 10:21 am

Doug --

The through holes in APC props are not centered --- the props are injection molded with a long-fiber re-enforced resin thru the hub section. The actual hole is drilled only to remove the injection sprue and may be off center both horizontally and vertically. I'm holding a 10x5 that's mis-drilled by almost 1/32".

Some props ship with adapters and some do not. When the prop is molded, the recess on the front and the larger hole on the backside are centered and in many cases, the drilled hole will be larger than the shaft the prop mounts on. To accurately center the prop on the shaft, you will need a locating ring that snugly fits the recess and prop shaft. This locating ring is used only to hold the prop in position until the mounting screw is tightened -- after that, the prop screw will hold the prop in position.

Unfortunatly, your only options are to turn or make your own bushings or find adapters on-line. If you're interested, I can go thru how I've made mine.

Here's a link into APC that gives a more complete explanation: http://www.apcprop.com/v/index.html

Choose Technical Info from the menu on the left, then Technical Support Notices.

andrew

Ken Cook Wed Jul 11, 2012 12:04 pm

Campbell's custom kits had bushings for APC props. http://www.campbellscustomkits.com/ You have to download the catalog and the parts are at the very end. Currently they're out of stock. I would certainly inquire about them. I had a few which were brass and they used the larger recess in the back of the prop to center the 5-40 screw. Ken

crankbndr Wed Jul 11, 2012 7:18 pm

Thanks for the help, think I know now how to make these props work.
Wow Campbells Custom Kits, Anderson In., where I was born many years ago.

dckrsn Wed Jul 11, 2012 8:10 pm

Ha! See Doug, you can go home again(at least via the internet). Smile

**Cribbs74** Wed Jul 11, 2012 9:30 pm

I picked up these APC 4.2x4 props this evening and I saw these spacers in bag so I grabbed a couple. They are still too large for the prop screw to center the prop but, I snatched em anyway. So what are they for? Better yet what can I use 4.2x4 props for? I grabbed them because they said 1/2A performance on the bag and besides how often does one come across props less than 7" anymore......

Ron APC props center hole KIjWt

mitchg95 Wed Jul 11, 2012 10:19 pm

cribbs74 wrote:I picked up these APC 4.2x4 props this evening and I saw these spacers in bag so I grabbed a couple. They are still too large for the prop screw to center the prop but, I snatched em anyway. So what are they for? Better yet what can I use 4.2x4 props for? I grabbed them because they said 1/2A performance on the bag and besides how often does one come across props less than 7" anymore......

Ron

i want to use those on my .049's but they always say "not for use on gas engines" so that always deters me from getting them, has anyone used these with good effects?

**Cribbs74** Wed Jul 11, 2012 10:24 pm

mitchg95 wrote:
cribbs74 wrote:I picked up these APC 4.2x4 props this evening and I saw these spacers in bag so I grabbed a couple. They are still too large for the prop screw to center the prop but, I snatched em anyway. So what are they for? Better yet what can I use 4.2x4 props for? I grabbed them because they said 1/2A performance on the bag and besides how often does one come across props less than 7" anymore......

Ron

i want to use those on my .049's but they always say "not for use on gas engines" so that always deters me from getting them, has anyone used these with good effects?

These ones said "For 1/2A Cl/stunt" or performance. Definitely nitro anyway. If you want I can swing by tomorrow and grab you a couple. They had some for electric too but, they were on another shelf.

mitchg95 Wed Jul 11, 2012 10:30 pm

thanks for the offer Ron, im stopping into the hobby shop next monday to buy a couple babe bee's, ill search for some when i go
thanks Smile

those props look mean for sure

**Admin** Thu Jul 12, 2012 12:08 am

Hub Hobby has a bunch of those spacers and an entire (well, close to entire at least) line of APC props including Master Airscrew and Zinger wood props if anyone ever needs something they can't find. They used to be loaded with every size of Cox prop but those have ran out (and I helped lol)

**Cribbs74** Thu Jul 12, 2012 12:11 am

Admin wrote:Hub Hobby has a bunch of those spacers and an entire (well, close to entire at least) line of APC props including Master Airscrew and Zinger wood props if anyone ever needs something they can't find. They used to be loaded with every size of Cox prop but those have ran out (and I helped lol)

By spacers do you mean like the ones I posted or ones that actually fit our engines?

**Admin** Thu Jul 12, 2012 12:16 am

cribbs74 wrote:
Admin wrote:Hub Hobby has a bunch of those spacers and an entire (well, close to entire at least) line of APC props including Master Airscrew and Zinger wood props if anyone ever needs something they can't find. They used to be loaded with every size of Cox prop but those have ran out (and I helped lol)

By spacers do you mean like the ones I posted or ones that actually fit our engines?

Not sure, I should really run up there soon anyway, I have a TD .15 to run! I need to get a prop and a mount LOL. Plus see how much more they raised the price of the Sure Start they have sitting in their case. I think it is up to $35 now!

Ken Cook Thu Jul 12, 2012 5:26 am

Depending on the prop, I just use small or large fuel tubing as a spacer. Even though the prop is off center, You can pretty much eyeball up the prop on the drive washer. Even though we can all agree it's not the best way to run it. Ken

stevej Fri Jul 13, 2012 2:46 am

I use Bob Mattes' trick spinners with APC props.
http://www.flyfreeflight.com/Site/Custom_Parts.html

crankbndr Fri Jul 13, 2012 2:40 pm

Ordered more APC props right from the APC web store. Larger selection, shippings a little high but fast.

**RknRusty** Sat Jul 14, 2012 9:36 pm

Just got back from vacation and saw this. Otherwise I would have a picture.
I use a donut of thick fuel tube that is the same outside diameter and thick enough to just fill the back hole in the prop without squishing, and balance it like that. They balance very easily. Then I screw the prop screw through the donut all the way(wet the screw first) and spin it onto the drive plate and tighten it. They all align and spin up with no vibration. I think the APC electrics are the only ones they ship with spacers.

gcb Sun Jul 15, 2012 12:03 pm

andrew wrote:Doug --
Here's a link into APC that gives a more complete explanation: http://www.apcprop.com/v/index.html

Choose Technical Info from the menu on the left, then Technical Support Notices.

andrew

Thanks Andrew, that link plus your explanation was great info. I knew some were offset but I didn't know why. I usually bush mine with fuel tubing.

George

**RknRusty** Mon Jul 16, 2012 10:10 pm

Here is a picture of what I do with APC props. 1/4" fuel tube works great.

Screw the prop screw and spinner all the way into the prop and donut before screwing it onto the engine.

Sand all the excess molding off the blades and the back of the hub. Balance it with the donut installed and use the flat ends of the balancer hubs on both sides of the hub.

stuntflyr Tue Jul 31, 2012 2:54 pm

Those APC 4 1/2x4's are perfect for hot reedies on Mouse Racers or Tee Dee's on Profile Proto models. Good planform, thin so they accelerate quickly, I like them.
I had a friend index my sons spinners and props for his 061 Profile Scale P-38. We needed all the power we could get with no vibration allowed, so i knew one stop at my machinist buddies would do the trick. For my stuff I use tubing and stuff.

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