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I have noticed this myself in the 201. When I'm on a long cruising flight, I move my seat to the back stop (at takeoff, I'm all the way forward to compensate for my short legs!) and I gain a few knots.

Fair enough! If I go through with the change I'll report out.

I appreciate people sharing their experiences and observations. I don't wish to be rude, but can anyone answer my original question, which was about a direct comparison in performance between the 3-blade "Blackmac" and the MTV-12 propellers?

I'm not saying in general that the conventional wisdom is wrong in all cases, only that there exist multiple credible sources of information that refute the generalization that 3-blade propellers must have lower cruise performance than two blade propellers. On this very site there are threads with people giving their observations of performance with the same airplane with different propellers. One thread links to a thread over at Van's Airforce, where a poster gives the results of his comparison of 3 or 4 different propellers on the same airframe, corrected to standard atmospheric conditions. The original owner of the engine for my RV-10 did a side-by-side comparison on his own RV-10 of 3 different propellers in the span of one or two days and observed that for the MT and Whirlwind propellers, they both had nearly identical cruise performance to an original two-blade Hartzell. Again, I'm not trying to pooh-pooh real world data, I'm trying to base a decision on it. I'm fairly certain that my old Blackmac 3-blade is a dog in cruise compared to the original 2-blade that was on my Mooney. Not sure why, back in the sands of time, an earlier owner chose to change to it, other than perhaps climb performance or looks.

So, Hartzell's 2-blade (https://hartzellprop.com/products/top-prop/mooney/m20a-g-m20j-2-blade/) weighs 62-64 lb installed. That's aluminum; I tried to find a composite prop that Hartzell advertises for the Mooney but couldn't. Maybe my search-fu is weak. Macauley doesn't list weights for their 2-blade propellers (https://mccauley.txtav.com/en/products?PropType=constant&OEM=MOONEY+AIRPLANE+COMPANY%2c+Inc.&AircraftModel=M20J+201&EngineType=IO-360-A3B6D+(LY))

I'm thinking I could save 25.3 lb on installed weight for the prop alone, plus remove the 50 lb ballast, for a net increase in useful load of 75 lb. I'm told that in both Mooneys and RVs, the MT props are very smooth. My 3 blade Macauley has a lot of vibration to it (which could be taken out with a good balancing, but it seems the wood-based props are inherently lower in vibration than metal.

That is the conventional wisdom, but there are multiple posts on this forum and other places that seem to contradict the OWT that a 3 blade prop is necessarily slower in cruise than a 2-blade. Edit: For instance: In any case, thanks for contributing! I'd like to hear others' experiences with both the Macauley 3 blade and the MT 3 blade.

Title says most of it. My '78 201 currently has a 3-blade Macauley "Blackmac" propeller on it that was installed a long time before I bought the airplane. From what I can tell, this prop weighs over 71 lb on the nose. The airplane climbs very well, but I have never been able to get book cruise numbers at any altitude with it. I have to carry about 50lb of ballast in the baggage compartment to keep from running out of nose-up trim when landing the airplane when solo. I'm considering replacing the Macauley with an MTV-12-B/180-59b propeller. I've read the various threads I could find here on the MT propellers, and the consensus seems to be it is a better option over 2-blade propellers, or at least a wash. I'm interested in other people's experience with the 3-blade Macauley, and especially anyone who's changed it out for an MT-12. What were your performance numbers for the 3-blade Mac versus 2-blade, or vs the 3-blade MT?

It's a 5.2 liter engine, specifications are at the link.

I don't think the comments here about the RV tip-up canopies are correct. Multiple RV pilots report that in flight the canopy, if opened, will "float" about 6" to 8" open, with benign flying characteristics. https://vansairforce.net/community/showthread.php?t=29202&highlight=tipup+canopy+open+flight Edited to add: On the other hand, there is one RV-6 owner that has reported a strong pitch-down moment when the canopy is opened in flight. Perhaps this behavior is specific to the RV-6, but it is by no means universal to the RV types. https://vansairforce.net/community/showthread.php?t=191312&highlight=rv-6+canopy+open

The engine is a UL Power UL520iS. https://ulpower.com/en/engines/ul520/ul520is

The Garmin G3X/GDU460 installation manual has a section (35.4.8) on calibrating the GMU11 or GMU22 magnetometer, so the displayed data is already corrected--the "deviation card" is built in and already taken into account before the magnetic heading is displayed.

For those that aren't familiar, local NWS offices will usually work with you to have a meteorologist visit with a group and present on weather topics of interest. If you have a local IMC Club, EAA chapter, or other aviation group (or even Scouts or other children's org), they'll usually be happy to do a presentation.

Skew-T is definitely useful. I attended a presentation a few years ago on it given by our local National Weather Service office.

On the same day you posted this, I was supposed to fly from western PA to the Gulf coast (MS). I was planning to leave at about 0700, which would have allowed me to get up above an IFR (not low) layer to the west of the Appalachians and skirt the edges of it until southern Tennessee, where it would have cleared up. I got to the run-up pad and wouldn't you know it, Cylinder #2 was totally dead on the left magneto. I taxied to a local shop and between them moving airplanes around inside their crowded hangar and other things, it was 3 hours later that we had diagnosed and replaced a bad lower spark plug, recowled, tested, and test flown around the pattern. At this point, I checked the weather again, and what had been a thin broken layer just to the south of the airport had become a solid overcast of indeterminate thickness, with temperatures in the freezing range, for about 100 miles south of my start point. I technically had the option to file an IFR plan starting at a fix at the southern edge of the overcast and go VFR underneath, but it would have forced me to fly lower than I'm comfortable with, and some of the airports along the way were then reporting LIFR conditions, which would constrain my options in both vertical directions. I made the decision not to go based on: 1. Unknown layer thickness and probable icing inside it (Garmin Pilot's icing model is very useful here) 2. Constrained options for VFR under the layer, with limited airports with approachable weather. I ended up missing some important stuff for work (because I couldn't get a commercial ticket in time to make my appointed time), but it's better than being a statistic balled up on the side of a hill in West Virginia.