GrahamC

It is a bit confusing, perhaps we have fronts and backs confused - to me the backside is the one that goes against the prop driver (closest to the engine) and the front is the other side. When reading APC's site that is the same impression I get. APC also recommends reaming from the front non-precison hole so as not to touch the precision hole (on the back).

The only reducers I have gotten with the APCprops always fit the larger hole on the backside. I primarly use the 4.2x4, 4.5x4, 4.75x4, 5.7x3, 6x2 and 6x3. Ihave a vague recollectionof some of the larger (ie 6.5x4 combat prop) being different but Idon't recall the details. I guess perhaps I assumed all APCprops where the same and I shouldn't - APChas such wideproduct rangeand I am notfamiliar with the whole line.

I run across many discussions on a variety of forums about this subject. Many complaints about why APCjust can't make a prop with one size hole that is centered (among others), some old wives tales and some well thought solutions to dealing with the props. I get the impression that a lot of users just buy the props and bolt them on the engines (electric, glow, diesel or gas) and don't give it any other thought. If it doesn't fit they drill out the hole, wrap some tape around the crankshaft or what ever short cut gets them to where they want to be. Irecall seeing someone enlarging the hole on a large APCprop with his pocket knife to put on his .60 size plane having broken the previous one on his last flight.

I should take some time an poke around on APC's website again, refresh my memory and perhaps correct some of my own mis conceptions.

While off topic for this thread it is an interesting topic.

cheers,Graham