Not a 10-6, but did use a 10-5 Master Airscrew on a B40 mounted to a P-40. Results were ok, but have since switched to an 11-4 Rev up which got me a little more RPM and lower lap time. (Line tension)

    You want to try different props from 10-4/5 through 11-4 and 4.5. I had good results with the APC 11-4.5. The Thunder Tiger 11-4.5 is another one people like. get as many as you can and try them all. You will probably like the 11" props best, or something between 10.5" and 11"
  Type at you later,
  Dan McEntee

I have had good success with APC 10x5 trim plane out and then try and find a better prop , only one better I have found is 10x6 Rev Up extra wide. But they will demand more nitro in engine to make the B 40 pull the prop. The APC prop always worked well for me 10 to 20 percent nitro fuel running in hard four stroke.

Joe Gilbert

Thanks so much for your recommendations.  There's a lot there to try and I have most of them and some others.  I was going to try today but I had put the B-40 in mounting holes that were originally used for an LA-40 which has a longer shaft. The 10/5 APC I was going to use wouldn't clear the end of the nose of the plane.  I did put some washers next to the thrust washer and a Brodak round 1/2 oz. round weight but I didn't try running it.  It's a used engine which I have never run, so I decided to go with another Banshee with an LA 40 on it which started fairly easily but was way too fast on 60 ft. lines with a 10/4.5 APC. I then used an old 11/3 wooden propeller but the needle didn't work right.  Other suggestions and experiences with props for the B-40 are still welcome.

Has anyone had success on the Brodak 40 with a MAS 10-5 three blade prop?

  Yes. If checked on a Prather pitch gauge, these pitch out at 4" pitch. If I remember the story correctly, this prop came about through the efforts of a Stunthanger member, I just can't remember who. He contacted Windsor propeller, told them what he wanted in a prop for all the modern .40s out there, they gave him a price and a minimum order number before production could begin. He took orders on the forum here, met the required numbers for production and then collected from everyone after they were shipped to him. I had some good results with the 12-6 three blade on bigger engines, so I ordered 6. When I got them, they checked out just like I thought they would on a pitch gauge andf flew them on several .40s. I was affraid that they would make these any more after that, so bought a few left overs. It came to pass that they were enough of a success that Master Airscrew has kept that size it it's line up, and I think have even added a left hand version. Another benefit is that you can repitch them pretty easy if desired, and price is pretty reasonable when carbon props are out of reach of most of us. If you really gotta have that three blade prop look, these work well and look good also.
  Type at you later,
  Dan McEntee

I have one of those 3 blade props.  I will try it along with others mentioned here.

     When you do and if you tach it, don't forget to set it for 3 blade!!! I have really messed with my own mind that way a lot!
    Type at you later,
   Dan McEntee

I've never had a three blade prop.  Is it safe to hand prop/chicken stick a three blade prop, or is using an electric starter the only safe way to go?

Joe Ed Pederson

    Nothing much different with a three blade. I don't think I've whacked my fingers any more with a three blade than a two. You want to be a little more positive with the motion and follow through, or if you have enough compression, back flip the prop. A chicken stick would be used as normal. If you have a model with a .40 on it, I'll lend you one to try out and see if you feel any difference, just for the experience. With a three blade you generally run an inch less diameter, and that may get you some better ground clearance on a short legged model if you need it, like flying in grass. And like I said, sometimes you just want that look!!
   Type at you later,
   Dan McEntee