Does a constant speed propeller ever pay for itself?

[Echo Tango]

I understand that fuel economy will increase with a constant speed prop.

And climb performance increases. But are they really necessary with the increased maintenance and upfront cost? Where is the break-even point?

I admittedly don't know much about them

[Andy Hill]

Hi Frank

I understand that fuel economy will increase with a constant speed prop.

IMO, not really. You will spend 90% of your time cruising at a specific altitude band and power setting. Buy a FP Prop optimised for that regime, and the VP Prop will have no better economy.

You might save a few cents each climb, but will lose that (and more) in weight, parts, overhauls, cost etc.

So if $$ is your priority a FP Prop is almost certainly the winner, but then is even an RV the right choice?

To me, the VP Prop "pays for itself" the moment I take off, and my 180HP engine gives 180HP through the Prop, not 100HP. I can do aeros from 60K to 200K and have carefree throttle handling. I have drag on approach/landing.

Only you can decide where your priorities and budget lead you - there is no one answer for all

[humptybump]

Frank, if you are only looking at "fuel ROI" then the constant speed propeller may not be a sound investment for you. However, a CS prop has other factors to consider. For example, if you have a fixed pitch propeller and it's been set primarily for cruise then you may find some high altitude runways are too short for you. Even at lower altitudes, the CS prop could one day "safe more than gas".

For those interesting in more than the occasional "gentleman's aerobatics", the CS prop has benefits to consider as well.

I'm not saying everyone should invest in a constant speed propeller. I didn't. I'm only pointing out that fuel burn is not the only "ROI" that may be relevant.

[Echo Tango]

Originally Posted by Andy Hill

Hi Frank

IMO, not really. You will spend 90% of your time cruising at a specific altitude band and power setting. Buy a FP Prop optimised for that regime, and the VP Prop will have no better economy.

You might save a few cents each climb, but will lose that (and more) in weight, parts, overhauls, cost etc.

So if $$ is your priority a FP Prop is almost certainly the winner, but then is even an RV the right choice?

To me, the VP Prop "pays for itself" the moment I take off, and my 180HP engine gives 180HP through the Prop, not 100HP. I can do aeros from 60K to 200K and have carefree throttle handling. I have drag on approach/landing.

Only you can decide where your priorities and budget lead you - there is no one answer for all

Thank you for the write-up. So it's not so much an economy thing as a performance item, related mostly to take-off and approach to landing/maneuvers.

Can you expand on the bolded part?

[PerfTech]

....The main benefits of the CS prop are stated already, but I must add that the performance in my aircraft is so phenomenally improved that it makes me feel its worth every dime, every time I fly it. One other consideration that should be stated is this fact. When the day arrives to sell the plane, you should recover 60% to 80% of the initial cost of the propeller in increased value. That makes it somewhat more cost effective. Thanks, Allan...

[rjbob]

I have the opportunity to fly several RVs besides my own and anytime I am piloting one with a FP prop, I think about how much better the experience would be with a CS prop on the nose.

My 7 has a blended airfoil CS prop up front.

Economy? The CS prop cost me many dozens of thousands of dollars more than a FP prop...because I wouldn't have bought my plane if it had a fixed pitch prop installed.

[BobTurner]

Originally Posted by Echo Tango

Thank you for the write-up. So it's not so much an economy thing as a performance item, related mostly to take-off and approach to landing/maneuvers.

Can you expand on the bolded part?

The engine will only put out full rated power at sea level, full throttle, and red line RPM. With a fixed pitch prop pitched for cruise takeoff RPM will be way lower than red line.

[Larco]

I have the 180 C/S. Anyone with a FP uses about 2 gallons an hour more using a higher RPM in cruise to keep up. Some have converted and are very happy, some have not and just keep spending the money on fuel and are very happy. Do the math and then do what makes you happy. It becomes a very personal decision really. 8-10K savings in a 1000 hrs and better resale value? :-)
Larry

[Neal@F14]

A CS prop will pay for itself the first time you need the extra takeoff and climb performance to clear obstacles on a high density altitude takeoff

[Greg Arehart]

Originally Posted by LARCO

Anyone with a FP uses about 2 gallons an hour more using a higher RPM in cruise to keep up.

I challenge that assertion. A properly pitched FP prop (i.e., pitched for cruise) will achieve a similar fuel burn to a CS prop. I won't argue that there are a lot of advantages to CS, not the least of which is the combined climb and cruise performance.

Greg