201 MT Propeller vs 3-Blade Macauley "Blackmac"

[1001001]

On 4/19/2024 at 10:52 PM, Will.iam said:

No one has directly answered your question because nobody had a 3-blade blackmac and went to the MTV-12 propeller or if they did they did not post their results here with before and after test.  You are the first, please post your results here after you do the switch so you can help other people out when they face that same decision, although with the factory not putting on a 3-blade blackmac I doubt there is very many other pilots in your shoes. Maybe ask the bonanza forum to see if they have had someone make this very switch before.

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

[Shadrach]

On 3/29/2024 at 1:02 PM, 1001001 said:

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.
 

It’s not an old wive’s tail. It’s physics. All other things being equal, each additional blade decreases efficiency.  Efficiency isn’t everything. However in the power ranges of the Mooney fleet, a 2 bladed prop is more efficient. Now, MT’s three blade may rival other two blades. If that’s the case, that just makes me wish they would make a two-blade version.

[Pinecone]

Like more things, there are trade offs.  More blades tends to improve take off and climb, but hurt cruise speed. 

To ME, a 3 blade that has little to no affect on cruise speed is a win - win.

[Will.iam]

On 5/10/2024 at 4:57 PM, 1001001 said:

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

I think why some are getting no speed loss at cruise with the three blade MT is due to partly a better blade design but also cg position. A more aft cg is less the horizontal stab has to counter thus less drag. You can see this yourself by flying at cruise with autopilot on and your seat as far forward as possible. Let the airplane settle on a speed. Now slide your seat as far back as possible and i see a few more knots of speed. So reducing weight off the nose if you are nose heavy like the K’s mid bodies and all the long bodies would help. So would moving the landing lights from the cowl to the wing. 

[KSMooniac]

I believe the fastest cruise performance for the J on the market right now is the metal 2-blade Hartzell Top Prop.  Behind that, I would say the original 2-blade McC 214 (round tip prop) and perhaps the MT MTV-12 3-blade composite prop.  The '77 2-blade McC 212 and other STC 3-blade metal props are the slowest.  If Hartzell follows through with their 2-blade composite Trailblazer prop that has the same profile as the current metal Top Prop, I expect that will be the optimal choice for us.  However I don't expect it to be reasonably priced after their changes this year.  

I've read a ton of anecdotal reports of Hartzell spinner cracking over the years, and Hartzell has a habit of getting AD's published every decade or two when then need to boost sales.  That is one big reason I went with MT and am still happy.  The Trailblazer prop is very appealing though! 

[Shadrach]

Optimal propeller application was explained to me thusly.  The most efficient choice is the prop with the minimum number of blades required to convert available power into thrust. Blade length, profile and RPM will determine how much power each blade can convert into thrust before it begins to lose efficiency. Once the the power delivered exceeds the capacity of the current blade configuration, it is advantageous to add another blade.  If a prop is well matched to the the power plant and rpm range, and all parameters are held constant, each additional blade will decrease efficiency.   At the power range, RPM range and and blade length of most any Mooney, two blades seems to be optimal.  I am dubious of the climb and acceleration claims as I do not see how a less efficient prop yields more performance. Perhaps there are some scenarios where there is a momentary advantage.  There are certainly other factors to be considered. NV&H, weight and aesthetics are all important considerations. The 4 blade MT looks absolutely menacing on a Mooney, but I have yet to see any hard data that shows it is a step up in performance.  Seems like it is mostly marketing.  I am willing to be educated, but I have not found a lot of easily digestible technical information on the subject that is centered on powerplants of 300HP or less.

[Tx_Aggie]

I have the two blade original Macauley. My cruise is 155-160 TAS, ambient air dependent. 1980 M20J. I am pleased with the performance / sound. 

[1001001]

On 5/14/2024 at 11:03 PM, Will.iam said:

I think why some are getting no speed loss at cruise with the three blade MT is due to partly a better blade design but also cg position. A more aft cg is less the horizontal stab has to counter thus less drag. You can see this yourself by flying at cruise with autopilot on and your seat as far forward as possible. Let the airplane settle on a speed. Now slide your seat as far back as possible and i see a few more knots of speed. So reducing weight off the nose if you are nose heavy like the K’s mid bodies and all the long bodies would help. So would moving the landing lights from the cowl to the wing. 

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.