Adding constant speed prop

So the new (to me) RV-9A will come with a fixed pitch prop, and I really want a c/s, as much for the drag on landing as anything else. Talked to a prop shop and it looks like a reconditioned prop would be about a grand less than a new prop from Van's, if the shop had one. Thoughts! Comments? And governor recommendations, pro and con? Thanks!

Ed_Wischmeyer said:

So the new (to me) RV-9A will come with a fixed pitch prop, and I really want a c/s, as much for the drag on landing as anything else. Talked to a prop shop and it looks like a reconditioned prop would be about a grand less than a new prop from Van's, if the shop had one. Thoughts! Comments? And governor recommendations, pro and con? Thanks!

Click to expand...

Ed, I suggest you fly the 9A for a while before you decide to change the prop. A C/S prop is the most expensive single item on your aircraft to maintain if you go by the book. There is no reason to install one just to help you land the airplane. An RV does not need a C/S prop to be a great performer. It adds weight, cost and complexity to your airplane.

Ed_Wischmeyer said:

So the new (to me) RV-9A will come with a fixed pitch prop, and I really want a c/s, as much for the drag on landing as anything else. Talked to a prop shop and it looks like a reconditioned prop would be about a grand less than a new prop from Van's, if the shop had one. Thoughts! Comments? And governor recommendations, pro and con? Thanks!

Click to expand...

Constant Speed Prop is the best performance gain for dollars spent that you can get for your RV. I also would want a Constant Speed prop on any RV that I own.

Buy the new prop from Van's. PCU is the best governor that you can buy. Do not forget that you need to change the soft plug in the crankshaft, governor drive adapter, oil line, and fittings. Lycoming has a Service Instruction for the conversion.

The only new maintenance item you add is the grease every 100 hours or once a year. The overhaul cost after 2,000 hours a fraction of the money you can save on gas over 2,000 hours. According to Allen Tolle, one can save 1.5 gallons of fuel per hour with a constant speed prop over the fixed pitch. Over the 2,000 hour time between overhauls, one saves enough fuel to pay for the constant speed prop.

Ask your friends that have changed from constant speed to fix if they would do it again. Ask your friends that have changed from fix to constant speed if they would do it again.

gasman said:

Ed, I suggest you fly the 9A for a while before you decide to change the prop. A C/S prop is the most expensive single item on your aircraft to maintain if you go by the book. There is no reason to install one just to help you land the airplane. An RV does not need a C/S prop to be a great performer. It adds weight, cost and complexity to your airplane.

Click to expand...

Respectfully, I could not disagree more.
Shorter take offs, better climb, better fuel economy, AND shorter landings.

Yes, RVs will have great performance with a good fixed-pitch prop, but only in cruise (unless one has a climb prop but then the phrase will be "only on take off, climb, and landing").

RVs work well with fixed pitch props but REALLY COME ALIVE with a Constant Speed prop.

I have flown quite a few RVs. Whenever I fly one with a fixed pitch prop, it performs like something's missing.

Convert to CS

I have a good condition used governor drive adapter and stainless oil line (w/steel nuts) for sale. Reasonable price. Photos of parts if you want them.

Don B

RV 9. Rebuild in Progress

While an RV with a CS prop is impressive, I'm not sure it worth the extra weight, complexity, and maintenance.

My Catto prop is cut as an Uber Cruiser and yet I can easily climb between 1600 and 2100 FPM. Granted the initial acceleration doesn't match that of a CS prop but it does cruise faster than one with a CS prop.

The only time I wish I had a CS prop is when flying formation with someone with a CS prop.

The -9 is speed critical on approach. Too fast and you will land LOOooong! But that is easy enough to learn to deal with.

I would love to fly a -9(a) with a CS prop for a bit to get a good comparison. The -9(a) cruises so well up high and lands so slow that I find it hard to believe there is an ideal prop for such a wide range of speeds. I've had both a catto two blade and a whirlwind ground adjustable and with both props I've experienced a static run +\- 2100 yet can over rev well beyond 2700 up to 10,000 DA or more. I usually have to get lean of peak, or back off the throttle so I don't redline. That's with a carb'd superior O-320.

My experiance converting to CS Prop

I did convert my RV6 from a Sensenich fixed pitch to a Hartzel CS compact hub prop after about 200 hrs flight time. Issue 1...does your Operations Letter permit it without getting a new Ops Letter from the FAA. It amounts to recertification & new Phase 1. My letter, which is from over 10 years ago, allowed me to modify without FAA or DAR assistance which some later letters will not permit. Issue 2...does your engine support the change such as hollow crank, Crankcase oil source, and governor pad on Accessory case or crankcase. My 0-320 had all this but the model number said it would not so one has to look.

What did I gain? Better takeoff performance since I can turn 2700 RPM on take off verses only 2200 RPM with the FP. Cruise? I feel, and I did not track the data well, that I lost some cruise speed slightly but gained rate of climb and better short runway performance. Landing? Airspeed control was not as critical with the CS verses the FP. With the FP airspeed had to be right on but CS allowed a wider tolerance and still land the plane which happens to be a taildragger. On landings the FP required me to start slowing about 3 miles from the airport to reach flap speed while the CS still requires some planning it is nowheres as critical.

Would I do it again? No question...YES!!! Is it needed, no, but it is very nice. I would rather go to a VFR steam gauge panel to save the $$$ for a CS prop if needed, BUT I would not fault anyone for going FP. The airplane changed from a small well balanced machine which handled very well to a more heavy airplane which smooths out any mistakes a ham fisted pilot can come up with (that would be ME!). The heavier prop added 15 pounds net to the weight and added some sort of gyroscopic qualities which adds considerable stability on the runway so it is a tradeoff. It makes you look like a better pilot than you really are...that's me again!! BTW, after I flew with this prop, I relocated to the New Mexico where there are mountains and high density altitudes and now I really like this prop!!!

I hope this helps with your decision.

Dick DeCramer
RV6 N500DD
RV8 Finish kit...CS prop planned
Las Cruces, New Mexico

I've owned an RV-4 fixed pitch (350 hours) and RV-8 and -8A with constant speed (100 hours). The question for me is not whether or not, the question is how -- which prop, which governor. This thread is NOT about pros and cons of c/s vs f/p.

Please stay on topic. Thanks. (And yes, I could have been clearer that the decision is already made.)

Back to your original questions....I'd take a fresh overhaul to save money - sure (as long as it wasn't one of those with the 100 Hour AD hub...). I've got a couple of Jihostro/PCU governors, and one old Hartzell, and the new governors are easier to adjust - but that could be because the old one is a bit dirty externally and has been painted a couple of times, making the adjusting screws hard to move. They all work fine.

Paul

I too think an overhauled prop is okay, BUT ask the shop how much metal is left. Each time they grind the blades a little metal is removed. What you do not want to buy is a reconditioned prop which is at minimum limits - at next overhaul you'll need new blades.

+1 on Bob's comment. Even if there is no damage, blades loose metal at overhaul. Nothing wrong with used blades as long as they have life left in them. A "first overhaul" with no damage should have plenty of life left in them at a fraction of the cost of new. On the other hand, the OH prop you buy today may not have another rebuild left. Know what you're buying.

comments from the experts?

....so Ed's original question was that he wanted a CS, and how to best go about it.
..but following comments about not 'needing' a CS made me think about performance.
As near as I can tell, from the Lyc. power chart, if you start the takeoff roll and are turning up 2150 initially, your are making about 75 hp....am I right?
Why would you not want to get more of the power out of your engine, when you really can 'appreciate and make good use of it'.? ( maybe 'need' is the wrong word!)
FP driver here.....Just askin'.