Whats the deal on APC props? Do they only work well on 4 cycle engines? I am running a MAS 11-7 on my FX46 which is on the front of my Midwest Zero. Flys fairly fast if you want or will hover at a few clicks above idle. I thought I would try some APC porps for better performance if thats possible. I was getting 14.5 K rpms with the MAS prop. I tried a 11-7 APC and the engine would only rev up to about 10K and was hard to adjust. I thought this too slow for a takeoff so I tried a 10-7 APC prop. Now I was in the 12K range which was fast enough to fly. I adjusted the engine and took off. The plane flew ok but not as fast as with my MAS 11-7. When I throttled down below 1/2 throttle the plane started to lose altitude very quickly. There was not going to be any hovering with this prop! I didn't realize that I would lose so much rpms with the APC prop. Is there an APC prop that does work well with the 46 size engines or do I just go back to my the MAS props?? I was going to try one on my FX61 engine but I am reluctant to risk my warbird based on my efforts so far.

Try Master Airscrews' Scimitar series!
They're the best (IMHO) for engines below .60 cu.in. above that APC's are better
Regards,
Patrick

MAS and APC don't measure Pitch the same way. An APC 11-7 would act more like a MAS 11-8 or 11-8.5 Or conversly the MAS 11-7 is more like an APC11-6 or 11-5.

All I know is on engines I run over 12K the MAS seem to work better on engines I run less than 12K the APC's seem to work better.

If you attend any competitive (any discipline) event that requires the absolute most out of any given engine you will find the Mas is in the minority compared to APC. Beleve it or not there are very real reasons for that and performance is only just one.

Now lets just talk about composite props a moment. All props experiance a negative pitching moment from aerodynamic forces (a tendency for the blade to flatten with rpm), propellors are very dynamic devices. The standard Mas is a very flexable design considerably more so than APC, now this is nice if your training simply because if you dig it into the runway all the time it won,t break quite as easy however this flexing plays havoc with performance. With a Mas as you increase RPM you can see a considerable forward flex and flattening of the blade. What is happening here is the pitch is considerably less than what it is marked. The Mas is far worse than the APC in this regard The Mas scimitar is somewhat better though.

The effect of this is a Mas and an APC both 11-7 are not even close in pitch when running. Now to really add to the confusion, I have checked many of both types among others new on the trusty Prather pitch gauge and the Mas is frequently not even close to the stated pitch. All mass produced props are subject to this error even wood type but the Mas is more so compared to APC.

Fred Burghdorf (spelling) 'Mr. APC' makes over 300 varietys of props and most you will never see in LHS with many special purpose sizes. Fred is a very active Pylon racer in 422 (thats the awesome ones) all over the country and thinks nothing of coming up with oddball diameter, pitchs, hub design, patterns and thickness ratios for all sorts of competitive venues beyond pylon.

Fastsky it sounds as though 3d stuff is your thing, great but may I suggest a 11-7 is not an ideal size for that use on a modern .40/.46 perhaps the APC 12.25X3.75 would be better or in the case for that use with a modern sixty the APC 13X4w. The ideal setup for funfly and 3d is not going to be for high speed flight. If that is what you want for your .40/.46 try among others APC D-1 8.8X 8.0,8.5 or even 9.0 narrow That D-1 means special hub design to withstand the 17,000 rpm range yo u will now be turning. Once agine with that set up if its a clean airplane you will be going far faster than you ever had before but you won,t be hovering.


Props are like ladies, try them all before you make your selection.


John

I agree with JohnBucker,most of my props are apc, combat planes I use mas because they don't break as much on landing in the grass,but for the quality and price I like apc,if mas or any other brand gives you the desired results,then use it.
Have a goodun,John

I race dominator quickee-500's and we are limited to only using a 9x6 apc prop. I spin that prop at about 17500 rpm, I just recently ran an apc prop at 19,000 rpm talk about speed I was cooking at about 130 m.p.h. with a thunder tiger motor .40 size with a 9x6. So apc are what i stick with.

APC are much stiffer and don't lose their pitch at RPM. You should put a 11x5 APC on that 46 and I think you will feel a difference!

Jason

Where do I get a porp?

At the porp store,don't you no nutton? Good tuck shopping.
Have a goodun, John.

Thankx Jason, I will give that a try with the APC 11-5!

John gave you a good report on props but from a fun flyers view the apc costs more and when you tip one they lose the tips real quick. A mas will not cost a much and they hold up better when you nose a bird over, you might take a small piece off a mas but a apc will take off a lot more.

Ditto the 11x5. Pete

I would run an 10-7 apc or 11-6 apc or 11-6 graupner.
Seth