MOONEY M20j : Propeller 2 or 3 Blades?

[Ragsf15e]

11 minutes ago, David M20J said:

like @Ragsf15e mentioned its the Engine/Prop combination that there isnt anything for.  The STC i have for the prop lists the -A3B6D but not the -A3B6.  Half the people I talk to say its fine and the other half say it isnt lol

Not sure who you’ve been working with, but it might be worth calling one of the bigger MSCs and talking to them.  I guarantee they’ve seen this before.  I’d try DMax or SWTA.  Don Maxwell Aviation, at KGGG or SW Texas Aviation which I think is between San Antonio and Austin.  They should be able to give you a relatively solid answer.

[David M20J]

@bluehighwayflyer McCauley 3 blade C3D36C415/82NGA-8 with STC SA704NE

[hubcap]

Some folks advocate the use of 2-blade propellers on 4-cylinder aircraft engines for "balance" reasons. Apparently a 3-blade propeller's harmonics don't play as well with 4-cylinder engines?

I am not advocating one way or the other. FWIW I have a two blade Hartzell on my 6 cylinder TSIO-360-LB

[EricJ]

6 hours ago, David M20J said:

@bluehighwayflyer McCauley 3 blade C3D36C415/82NGA-8 with STC SA704NE

Is the text of the STC available anywhere?    I tried to find it and didn't come up with anything.   An AML would be important if there is one.

 

[David M20J]

17 minutes ago, EricJ said:

Is the text of the STC available anywhere?    I tried to find it and didn't come up with anything.   An AML would be important if there is one.

 

this is what I have

[EricJ]

39 minutes ago, David M20J said:

this is what I have

That's an AFM page, which isn't encouraging, but it's not the STC/AML.   The FAA page for the STC says it applies to M20 models B through J, but doesn't include the text of the STC.

https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/2C5365F822D4F55485256CCB0060191A?OpenDocument

 

[David M20J]

10 minutes ago, EricJ said:

That's an AFM page, which isn't encouraging, but it's not the STC/AML.   The FAA page for the STC says it applies to M20 models B through J, but doesn't include the text of the STC.

https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/2C5365F822D4F55485256CCB0060191A?OpenDocument

 

sorry I thought I selected the right picture

[EricJ]

That's only the first page.  Somewhere there will be a page that shows any engine limitations for the M20J.   If it restricts it to IO-360-A1/A3B6D like the AFM says, I'd try to contact McCauley and see if there's a later revision of the STC that allows installation on an IO-360-A1/A3B6.

 

[carusoam]

@David M20J see Eric’s note above…

-a-

[David M20J]

ill see if i can give them a call tomorrow

*UPDATE*

I called McCauley, they don't own the STC im looking for, they gave me the info of the current owner.  the -A3B6 is not on the STC and the current owner no longer wants to deal with it so they never added it...

time for a new prop...

Edited March 28, 2022 by David M20J

[201Mooniac]

If you are looking at a new prop, I'd suggest a call to Peter Marshall at MT as he was incredibly helpful when I upgraded and he had a prop in stock and quoted a much shorter delivery than the dealers.

Peter Marshall

Vice President

1180 Airport Terminal Drive

Deland, Florida 32724

Phone: (386) 736 7762 Extension-204

Fax: (386) 736 7696

[John Mininger]

On 3/28/2022 at 1:16 PM, 201Mooniac said:

If you are looking at a new prop, I'd suggest a call to Peter Marshall at MT as he was incredibly helpful when I upgraded and he had a prop in stock and quoted a much shorter delivery than the dealers.

Peter Marshall

Vice President

1180 Airport Terminal Drive

Deland, Florida 32724

Phone: (386) 736 7762 Extension-204

Fax: (386) 736 7696

I completely agree. 

I had a 3-MT installed on my 1977 J in Deland last month. It was $14,200 installed and balanced. Pete Marshall said that they try and keep one in stock for the Mooney's with 4-cylinder engines. But if I got the last one they had in stock, I don't know what the lead time would be.

Tim Jodice did a very complete Pirep on the MT that he installed on his J, so I won't repeat everything here except to say that my experiences mirror his. Look up 201 MT Propeller pirep from 8/5/2020

I would definently buy an MT again.

[John Mininger]

Tim Jodice's Pirep is at:

There's also a good article about composite props in the February 2022 issue of The Aviation Consumer.

 

[DEGWS]

Hi,

anyone have an idea how to index the 3 blade prop on the A3B6D Engine?

Does it make any difference regarding vibrations in the cabin. 
With the two blade it was a big difference after converting from A1 to A3 Engine.

How it is with a 3 blade?

 

thanks!

[EricJ]

5 hours ago, DEGWS said:

Hi,

anyone have an idea how to index the 3 blade prop on the A3B6D Engine?

Does it make any difference regarding vibrations in the cabin. 
With the two blade it was a big difference after converting from A1 to A3 Engine.

How it is with a 3 blade?

 

thanks!

The conversion between A1-A3 just relocates where the bushings are on the hub flange, and the prop manual should show how to install it relative to the bushings.   So the prop manual should have that info.

[Pinecone]

On 3/27/2022 at 4:59 PM, hubcap said:

Some folks advocate the use of 2-blade propellers on 4-cylinder aircraft engines for "balance" reasons. Apparently a 3-blade propeller's harmonics don't play as well with 4-cylinder engines?

I am not advocating one way or the other. FWIW I have a two blade Hartzell on my 6 cylinder TSIO-360-LB

Just saw an article in Mooney Flyer from Top Gun about this.  And he recommended to not use 3 blade props on 4 cylinder engines.

[201Mooniac]

1 hour ago, Pinecone said:

Just saw an article in Mooney Flyer from Top Gun about this.  And he recommended to not use 3 blade props on 4 cylinder engines.

Seems not to be true for the MT 3 blade prop as it was suggested by Top Gun when I needed a new prop two years ago.  Also, they put a 3 blade MT on their M20F/J.

[Pinecone]

Good to know.  Article was from 2013.

[Ragsf15e]

On 6/30/2022 at 7:18 AM, Pinecone said:

Just saw an article in Mooney Flyer from Top Gun about this.  And he recommended to not use 3 blade props on 4 cylinder engines.

You do hear that a lot, but my old 3 blade mccaully on my F seems fine.  I have heard a few folks that thought theirs had more vibration than a 2 blade, something about 3 blades on a 4 cylinder, but hasn’t been my experience.

[Hank]

18 hours ago, Ragsf15e said:

You do hear that a lot, but my old 3 blade mccaully on my F seems fine.  I have heard a few folks that thought theirs had more vibration than a 2 blade, something about 3 blades on a 4 cylinder, but hasn’t been my experience.

Yep. The 3-blade Hartzell on my C is balanced to below 0.1 is. It's pretty smooth, climbs well, and with a 201 windshield I cruise 145-148 KTAS, pretty good for a 140-knot plane. But my CG is a little forward.

[KSMooniac]

Wait until you try 0.01 IPS!

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