Answers to Questions
Gary,
The sheared tips are Vans. As far as performance, it is too close for me to call. Vans tips have more of a rounded edge which are rumored to have better speed performance than the competitor...but it's all pretty close. I would like to think I got a knot or two, but it was more about the look for me. Personal preference, but I like the way the sheared tips break up the Hershey bar look in plan form. I also like being able to get the tip lights inside a fairing. (There are others at my field that would disagree, but that's what makes for friendly banter. I may switch back to the Hoerner style if one of the guys at the field starts to tell me he likes the sheared tips!). The tips add wing area, so stall speed should be a bit lower, and roll rate a bit slower, but again, to close for me to tell.
Grant,
My Sensenich had an 86 pitch. I was lucky if I got somewhere between 1900 - 2000 static, so I was missing out on quite a bit of power on takeoff and initial climb out. Even with this fairly aggressive cruise prop, the airplane would still unload and allow me to exceed 2700 rpm at full throttle. In addition, keeping up with the 180 hp constant speed crowd flying out of Hicks required over 2600 rpm when they were at 24 square. (Pushing too hard for my liking)
The choice for the 151 was pretty simple for me. I had a long cowl (with 12" spinner) and short gear. Since I didn't want to switch the cowl, I needed a CS prop with extended hub. Hartzells with extended hub for the O-360 were too heavy for my liking, and just about as expensive as the Whirlwind. The 3-blade prop is 68" in diameter and that helps with the short gear. Additionally, the Whirlwind 200RV is not available in an extended hub version so that was out of the running. I used the Lancair spinner (sold for the 151 by Whirlwind) since it is just a shade over 12 inches in diameter. (I did end up refairing and repainting the cowling to blend the spinner a bit better....I could have lived with the minor mismatch, but I'm anal-retentive like that)
In the end, I got 14 lbs off the nose by switching to a constant speed prop. The aircraft still unloads well. I typically run 20 inches at 2400 rpm when the 6s are running 24 square. With respect to aerobatics, the 151 goes flat with no oil pressure, for serious aero you want the blades to go course with no pressure. I typically only do rolls & Immelmans so I really don't get into many things that require quick transients. But I will say that the 151 has a fairly small actuation piston requiring high (475 psi) relief pressure in the governor. That coupled with the very low inertia of the prop make the prop hunt more that others with rapid throttle transients. (Again, counter to what you want for serious aerobatics)
For the way I fly, I love the prop! Everything is a compromise, but I don't find the RPM restrictions to be a problem, and the the climb, cruise and braking performance more than make up for the drawbacks. IMHO