1001001

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.

I have a hot start procedure that works every time on my airplane. The guy I went to for my Mooney transition training taught me this--he used it in his F model when he still had it. Works fine in my J (should, since it's the same engine setup, pretty much). It works regardless of how long the engine has been resting since shutdown, as long as it's hot. 1. Mixture cutoff 2. Throttle full for 30s 3. Throttle back to 1/2" to 1" open 4. Crank until start 5. Advance mixture, adjust throttle This usually results in a start within a few revolutions.

One thing that works on some aviation windows is an "Automatic center punch" like this: https://smile.amazon.com/General-Tools-78-Automatic-Center/dp/B00004T7RF/ We tested one on some pieces of canopy from a Van's RV aircraft and it worked. One of our local builders has a damaged but intact canopy, and we're going to test it on that and hopefully video the results, when we get around to it. The benefit of the automatic punch is that you don't have to have a long swing to build up energy, and you don't have to be particularly strong to use it. In the cramped quarters of an aircraft cabin, it's hard to get a swing going. Crash axe/hatchet would probably be even better than the window breaker tool, but it still requires space to swing it.

Probably Savvy anonymizing a client's aircraft.

+1. I have also gone through Jesse Saint in Florida. I bought a used 430W for my old Warrior and agreed with the seller that he would ship it there and Jesse would test it. If it passed the tests, I'd send the check to the seller and then when the seller released it Saint shipped the unit to me.

Another cause could be a leaking fuel line on that cylinder. The line could be cracked/broken or maybe the fitting could be loose. ask me how I know...

Yes. If the engine was being operated rich of peak, a partial blockage on that injector would cause the cylinder to go lean, and the EGT would rise, as long as the blockage wasn't so severe as to take the cylinder extremely lean. I just recently experienced this, although I was operating the engine lean of peak, so when the blockage occurred, the cylinder was starved for fuel and I experienced significant engine roughness. Thanks to Our Friends at Savvy for looking at this for me and for helping explain it to me and help me better understand the event. One thing you should see when an injector clogs is that the fuel flow will remain constant, but the EGT on the blocked cylinder will change (down, if you were LOP prior to the clog, and up, if you were ROP prior to the clog) and the other cylinders will likely change as well (in the opposite direction) as the fuel from the clogged injector is redistributed to the others.

Thanks, everyone, for the replies. There is some really useful information here.

Interesting stuff, thanks!

Right, see that extra induced drag is what made me think that the tradeoff would be nil, however, moving mass around inside the airplane should allow favorable trim changes to get best cruise attitude, to a point. There has to be some optimum point at which adding ballast doesn't make an improvement anymore, because any gain in performance of the wing will be countered in drag induced by the tail. But up to that point, you'd think it could be beneficial.

I recently took a long trip in my 201, which lasted just under 5 hours due to ridiculous headwinds. I am not a tall person, at 5' 8", and weigh about 185 (clothed). My legs are kind of short, so I usually fly with my seat all the way forward so I can manipulate the rudder pedals and brakes fully. About two hours into the flight, I was getting a little restless and decided to stretch out, so I moved the seat back to where I could touch the rudder pedals (no yaw damper). After I did that, I noticed the airplane started to climb (single axis autopilot) so I corrected altitude and adjusted the trim downward. After I did that, the airplane seemed to pick up several knots of ground speed (like 3-5, if I recall correctly). I thought maybe that was due to a headwind change, but found that my TAS had increased as well. I guess in theory, a nose-down trim change should result in a small speed increase, but I was surprised at the magnitude of the gain. Does this make sense? I was under the impression that the pilot seat was so close to the CG that it wouldn't make much of a difference, but I probably moved the seat back around 4"-6" or so, so my moment shifted a bit. I haven't done a W&B calc on what that change would do, but I thought the observed effect was interesting. I usually fly with about 30 lb of ballast in the luggage compartment (it seems to help with the flare in landing) when I don't have rear passengers. Would increasing the ballast cause me to have to trim more nose-down and imprive cruise speed? It seems like it should, to a point. Does anyone else experience this?