3 bladed prop on vintage Mooneys

[NotarPilot]

Is this something to avoid when looking at older 4 cylinder Mooneys for a purchase?  I heard they can have vibration issues.  Thoughts, comments, concerns?

[GeorgePerry]

Seems to be airframe specific.  Some have a funky harmonic...some don't.  The issue seems to be more prevalent on E's and F's than on J's.  Don't know why...just what I've seen from personal experience. 

I wouldn't pass on an older Mooney just b/c they have a 3 blade prop.  The up side to a 3 blade prop is the prop hub will be newer and won't be subject to the Eddy Current inspection AD that effects early Hartzel "A" hubs.

 

 

 

[gregwatts]

A three blade prop is generally a sign of a previous gear up. I can only speak of a C model that had a three blade prop........the vibration caused me to sell the plane. The new owner of that same C model had the prop dynamically ballanced twice.....and then sold the airplane.

[Shadrach]

The reason that I believe the J models do better with the 3 blade is that the cranks on all of them a counterweighted. Also the prop on the latest J models indexed differently.

While the 3 balde works fine on some vintage birds, the speed loss is noticeable. They do look sexy though.

[Scott Aviation]

I have an "A" model and did quite a bit of homework 2 years ago when i replaced my hub/ prop and spinner with the new scimitar top prop.

I have to agree that the 2 blade is the way to go. As noted some planes do fine with the 3 blade and some have a noticeable vibration. I also picked up 5 pounds of useful load and 1 inch of ground clearance with the 2 blade. ( It does not sound like much but i have to taxi on grass to get to the hanger.)

[skyking]

Sorry Chris. That was my post. I have no idea why it came up under your handle.

[DrBill]

I have a 65 E and a 3 blade prop. Like Gregg indicated, previous owner had gear up.  It's really nice and quiet and I feel that I climb a lot faster than a 2 bladed F on the field.  I'll keep it !

BILL

 

[SkyPilot]

I have a Hartzell three blader. Nice prop no vibration trouble. Mind you, I used to fly a PZL engined Otter so anything seems smooth : )

If I could get 5 mph more out of a 2 blader that would go on at next overhaul, but I have a few years to go before worrying about that

[Hank]

A 3-blade prop is not a reason to avoid a particular aircraft. Review the logs, check the plane; if it looks good, test fly it. Many vintage pilots are happy with the 3-blade prop; many others insist that they cannot operate smoothly. The only way to tell if an airplane is smooth or vibrates is to ride in it. Mine is great, and apparently the speed loss is balanced out by the 201 windshield because I still make book speed.

[Seth]

As mentioned - the vibration issue is plane specific. 

Personal experience:  I owned a 1967 F Model with a three blade that ran very smoothly.  It was a great climber, and frankly, was still pretty quick for an F at 145 to 148 knots and twice touched 150.  The three blade was added after a gear up by the previous owner.  The engine had 100 hours on it when I purchased it and  sold it with about 600 hours on it. 

And yes, the three blade prop is sexy.  One of our Mooneyspace members showed me a picture of a four blade prop on a Mooney!  He said that was even smoother.

The Missile also has a three blade prop - but it also has 300 HP!

Take care,

-Seth

[Shadrach]

Quote: JimR

Wow, Hank. I'm impressed with any vintage Mooney that makes book speed. Don't change a thing!  

[Guest]

I added my three blade during a complete restoration, not all three blades are due to a gear up. The reason I added the three blade was pretty simple, initial climb rate too me with the 2  blade on my 1970 C and most E and F models I have flown on a typical summer day stunk.

I have no vibration problems with the Hartzel and cowling enclosure and several others I've talked with report the same. 

[NotarPilot]

Thanks for the comments and great info.

[Shadrach]

Quote: JimR

Mine does so easily.

[banjo]

with a 3 blade prop you are going to lose about 5 to 7 knots on your cruise speed

for a small gain in climb

 

 

[clh]

Quote: banjo

with a 3 blade prop you are going to lose about 5 to 7 knots on your cruise speed

for a small gain in climb

 

 

[KSMooniac]

Any prop replacement should lead a savvy buyer to investigate what prompted the change.  I too elected to replace my OEM prop with an MT as an upgrade.  My bird has never been on it's belly <knocking on wood> and someday I'll probably do the 1-pc belly upgrade as well on my own dime.  Hopefully after I've replaced the prop and belly (and maybe o/h the engine) on my own dime I won't then have a gear-up landing!  

[jetdriven]

Cardinal RG loses 3 knots in cruise when going to the 3 blade.  I think the mooney is about the same from what owners say here.

[flyboy]

I have a '61 model  B with a 3 blade McCauley. As far as I can tell this airplane has never been on its belly. I can't say if the two blade is faster or not, as the 3 blade was there when I bought it. I do know that this is a super smooth running 4 banger. I would love to fly/ride in the same model with a two blade prop in order to compare how smoothly it runs. One thing that really hurts with the 3 blade is balance. That extra blade adds quite a bit of weight to the nose of an airplane that is already nose heavy. The fuel bladders also move the CG forward. With 2 real people (not 170 lb. FAA people) on board the airplane is well out of CG limits. I can load the baggage compartment with cases of oil to bring the CG in. This however, makes the airplane a little unstable to me. After rotation the nose wants to keep climbing skyward, I have to really be on top of it during the first few seconds of flight. Retracting the gear does move the CG back slightly as the nose wheel retracts aft in Mooneys. By that point I have plenty of airspeed to make me feel more comfortable.

[flyboy]

^{A 3 blade composite might be a good choice due to less weight.}

[mcpilot]

THe 66E that I used to own had a 3 blade.  The gent that I bought it from had a C model and this E model.  He took the two blade off of my E and put it on the C and took the 3 blade off of the C and put it on my plane before he sold it to me.  

 

Long story short is that that plane was such a shaker, I sold it.....  It shook so bad that the small screw holding the doghouse engine baffling would unscrew themselves and I would find them in the cowling when I preflighted....

[stevesm20b]

I have a 61 B model with the 3 blade Hartzell prop. I don't have any vibration problems. I went to the light weight starter and the Plane Power Gen to Alt conversion and it is actually lighter than it was with the two blade with the stock starter and generator. I didn't notice any speed loss going to the 3 blade. But I had the engine overhauled at the same time. I did notice a 150 to 200 feet per min climb increase with the 3 blade prop. My plane has most of the speed mods. 201 windshield, cowl enclosure, aileron seals, flap gap seals, wing root fairing, dorsal fin, tail root, rudder and elevator covers and brake cylinder rotation. I usually cruse 150kts between 7,000 and 9,000ft.