Climbing Prop

[Bnwii62]

I have a 1968 Mooney M20F and I want to upgrade to a three blade climbing prop. I'd like to get input on the Hartzell, McCauley, and MT propellers. Can I buy rebuilt as well as new? Anyone with experience with rebuilt or used props? I'm trying to keep expenses down. Which prop do you believe it's the best?

[Hank]

Calling our local prop guy, Cody! @Cody Stallings

[gsxrpilot]

Isn't the whole purpose of a constant speed prop, that it is climbing when you need climb and cruise when you need cruise? 

[carusoam]

Welcome aboard bnw...

What are you looking to do?

By the answers above, you can see the climb prop is a term used to describe a prop with fixed pitch...

Your prop, when set to max rpm is your climb prop...

Now...

If you are hoping a three blade prop will do better than a two blade prop... sure, that can help...

But, it is going to be small percentages of efficiency...

It won’t change the important part... how much HP the engine is producing...   

 

Use the search function... and find the experiences of MSers that have gone with the MT prop... there are a few around here...

Cody is our prop guy...

The more you organize your questions the better the responses will be...

hmmmm... Mooney props and power distribution.... averages about 100hp per blade...

A two blade prop on a Long Body Mooney was not very good at getting off the ground... but, that is with nearly 300hp of an IO550...

Best regards,

-a-

[Shadrach]

2 hours ago, Bnwii62 said:

I have a 1968 Mooney M20F and I want to upgrade to a three blade climbing prop. I'd like to get input on the Hartzell, McCauley, and MT propellers. Can I buy rebuilt as well as new? Anyone with experience with rebuilt or used props? I'm trying to keep expenses down. Which prop do you believe it's the best?

Do you feel that your F model needs more climb performance? It’s likely going to weigh more and slow you down. I flew my 67 F around the patch last Sunday. A deficiency in climb was not the first thing that came to mind...

 

[carusoam]

Great point, Ross...

Back to bnw, does your climb rate resemble Ross’ at all...

Of course, weight, OAT, and engine health will matter...

Best regards,

-a-

[Ragsf15e]

I have the Mccauley 3 blade on a 68F. Changing from a 2 blade to a 3 blade wouldn’t be my first “upgrade” choice. In my opinion, the change in TO & climb is negligible, and it probably costs you a couple knots.  It will definitely cost more to overhaul and it definitely weighs more.

I think a bunch of Mooneys got 3 blade props in years back when they had a prop strike and mccaulley was selling theirs cheaper than most 2 blades.  That’s just a guess, but mine had a prop strike in 2004 and thus the 3 blade.

Heres the deal though... it looks cool and chicks dig it, so I say go for it if that’s what you’re looking for!

[Bnwii62]

I live in Utah and I fly into a lot of airports that are at high elevations so I thought the climbing prop would help. It also gets pretty hot up here too. Do you feel like the 3 blade is worth it in these higher altitude airports?

[Bnwii62]

I also have a turbo normalizer and oxygen, so I can get up high. Is the 3 blade as good or better up in the higher altitudes?

[TTaylor]

Not sure where you are located in Utah.  Our F has a 3 blade prop and works well. That said, I don't think there is a significant difference in performance between a 3 and 2 blade worth changing props.  Are you operating off of a very short strip? If not, then climb performance is really a function of horsepower and not the prop.  As others have said, a constant speed prop is designed to give you good performance in climb and cruise.  Are you using your engine rpm for maximum performance?  HP is a direct function of rpm and fuel flow.  When you need better climb you need to use higher rpm, fuel flow, and in your case manifold pressure.

[gsxrpilot]

I fly a 252 with the original two blade canoe paddle prop. I've been talking with Hartzel about developing a new, composite scimitar prop for the 252. But they claim they haven't been able to come up with a design that is better than what I've got for high altitude flight.

[Ragsf15e]

1 hour ago, Bnwii62 said:

I live in Utah and I fly into a lot of airports that are at high elevations so I thought the climbing prop would help. It also gets pretty hot up here too. Do you feel like the 3 blade is worth it in these higher altitude airports?

Your TN is the best TO/climb bang for your buck.  I really don’t think the prop will add much except weight.  Density altitude affects more than just engine power (which your TN helps get back).  It’s prop and wing efficiency as well.  You’ll need longer to accelerate to a given takeoff speed because the IAS is lower at high DA.

Even with TN, these things are still gonna hurt, but the 2 vs 3 blade hasn’t really proven to help much on the older Mooneys in practice.

[carusoam]

Potential Next steps...

Get a copy of CloudAhoy for your iPad...

Connect it to a portable WAAS source like a SkyRadar...

Measure actual T/O and climb performance... on various days of various OATs.

 

-or-

For a lot more... you can get something with 300, 305, or 310hp to significantly improve your climb rate...

The 310hp comes with a modern three blade TopProp...

 

Hanging a TopProp without adding power probably won’t get that seat of the pants feeling that comes with the HP....

PP thoughts only, not a mechanic...

Best regards,

-a-

[Bnwii62]

Thanks all of you for all your advise.

[Tim Jodice]

On 2/24/2021 at 7:32 PM, Bnwii62 said:

I have a 1968 Mooney M20F and I want to upgrade to a three blade climbing prop. I'd like to get input on the Hartzell, McCauley, and MT propellers. Can I buy rebuilt as well as new? Anyone with experience with rebuilt or used props? I'm trying to keep expenses down. Which prop do you believe it's the best?

What model of propeller do you currently have?

[M20F]

On 2/25/2021 at 12:12 PM, Bnwii62 said:

I also have a turbo normalizer and oxygen, so I can get up high. Is the 3 blade as good or better up in the higher altitudes?

1-11000K feet probably not.  As you get higher and the air gets thinner probably yes but not enough to matter.  The TN allows the engine to make the same power but the prop is what uses that power and it becomes less efficient as the air gets thinner.   This why back in the day big giant props and geared engines were the rage.  
 

That being said you start crunching the numbers you are going to climb about 500-750FPM give or take at 120 mph IAS (it takes me @ 52 mins to FL250 as example). The amount of speed I loose climbing for an hour and burning 1/3 of my gas makes climbing to FL250 not very worthwhile unless it is a very long flight or the winds are crazy strong.

You will find 9-12.5K is the sweet spot for a TN.

[carusoam]

Great details Mike!

Thanks for sharing them...

Best regards,

-a-