With carbon 3-blades getting harder to find and staying expensive, is there a suitable APC prop for the PA40 UL? Model is 603-inch Oriental Plus, with carbon pipe. Not sure on finished weght but estimate 50-55 oz.

I would use a wood Zinger 11 x 4 Pro, or a Cyclone 11 x 4.5 , before I used an APC, both of those props have been used with great success

Randy

Hi Kim:

Don't  know how many come in a plethora but a kind offer nonetheless. I have one or two, and do have a couple of carbon 3-blades, but nothing lasts forever. I will keep your plethora in mind.

Mike I used the APC 11-4 on my RO Jett .40s for a couple years.  They worked fine.  Flew 60-64 ounce birds at about 10150 rpm launch.  The engine ( on pipe ) wouldn't be too different I don't think.

Dave

  I would also try a 11.75-4.25, which was originally designed for the PA40 (not UL).

    Brett

Steve,  you are saying 'not good' but not saying why or how.  What I and some others have done is to drop 'Rs' some, up pitch and pull the pipe out.  I've never run that engine but I'd try pulling the pipe back in 1/4" increments and then squeeze up the needle-or leave the needle and go up on pitch- not diameter.  I'm thinking 12" is nearly as far on dia. as I'd go on that.  If nothing else you'll get a good sense of how all the pipe, settings and pitch all work together on your particular set up. I fine tune pipe length to get equal lap times from start to finish of the run once the engine likes the setting and I've set the pitch to get the bite I'm happy with.

Dave

Steve,  you are saying 'not good' but not saying why or how.  What I and some others have done is to drop 'Rs' some, up pitch and pull the pipe out.  I've never run that engine but I'd try pulling the pipe back in 1/4" increments and then squeeze up the needle-or leave the needle and go up on pitch- not diameter.  I'm thinking 12" is nearly as far on dia. as I'd go on that.  If nothing else you'll get a good sense of how all the pipe, settings and pitch all work together on your particular set up. I fine tune pipe length to get equal lap times from start to finish of the run once the engine likes the setting and I've set the pitch to get the bite I'm happy with.

Dave

Dave...The current setup only gives me about 50 rpm leeway at launch between too slow, just right, and too fast. Can't see anything good about that. Needless to say, I'm pretty careful about getting it warmed up before I head to the handle. The .46 VF seems to want to run faster than I'm running it. Pipe length is set at 18.75", which looking at Randy's charts, may be too long? Exhaust timing should be stock at 145 deg., I believe. Pipe length has not been changed since I got the plane from Norm Whittle (his last IC model). It certainly seems too long, based on Randy's charts. Looks like I need to shorten the pipe quite a bit, but maybe I'm wrong? 

To complicate things, this model only has clearance for 11.5" dia. I have a few 12" CF three bladers that are nominally 4" pitch...but I'd like to save them for next year's model, with a PA .51, rather than cut them to 11.5" and make them useless on the .51, since this season is over and done. Yet, when the weather is ok, I'd still like to fly this one, and also improve it for use as a backup next season.    Steve