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CS/FP Price Difference

P

pilot28906

Well Known Member
I am narrowing down on an engine solution (IO-360 180HP) so am now looking at props.

Am I reading this correct?

Hartzell CS: $7775 Sench FP: $3675
FWF Kit: $5750 FWF Kit: $3825
Total: $13,525 Total: $7500

Cost delta for CS vs FP: $6,025

Is this correct?

Is the CS really worth $6K? I understand the difference but that is a lot of $.
 
The value of the difference is a builder preference. There is no correct answer, only the correct answer for YOU. Do a search in on this site of "Fixed Pitch vs Constant Speed" and you'll likely have hours of reading to do with no clear answer in sight.

The reality is that FP props will be less expensive to own and operate. CS props will offer better takeoff, climb, and landing performance, but may or may not offer an improvement at cruise. CS props can be expensive to maintain.

Back to your financial comparison - there are FP wood props available for ~$1,000, so the cost gap can be bigger than what you showed if you choose one of the inexpensive props.
 
Depends on your mission. Yes the improved takeoff and climb performance is very nice. Also, don't discount the improved braking action of the cs prop. I fly a lot of formation and aerobatics; I would not have a fixed pitch prop!
 
RV8Squaz said:
Depends on your mission. Yes the improved takeoff and climb performance is very nice. Also, don't discount the improved braking action of the cs prop. I fly a lot of formation and aerobatics; I would not have a fixed pitch prop!
Click to expand...

I was fine with my Sensi FP prop until a couple of NOTEWORTHY underruns/overshoots sold me cold on the absolute NEED for a CS Hartzell if I'm gonna fly formation. (...and, yes, I do fly a LOT of formation.)

Result: An overwhelming need to answer the question, "Why, oh why, did I EVER waste my time and money on a FP prop?"
 
Very personal decision indeed but burning less fuel in cruise if you travel a lot plus resale value alone will probably get your money back.

This has been discussed so much you might want to read stuff from the archives.
 
I bought a sterba prop for about $600. Still waiting for it in the mail, but I couldn't justify the money for a fancy prop. I will buy a constant speed prop eventually, but that wont be for several years. Constant speed is better, no doubt. But money is a thing, so I'm going with a wood prop for now.
 
One other key factor, the CS prop is SIGNIFICANTLY heavier than a FP orop, more so if you compare it to a composite FP prop like a Catto.

The good news is, you can start flying with a FP and change it to a CS prop later, if you buy the correct engine.

I have a FP prop on my O-360 powered -9 and the only time I wish I had a CS prop is when flying formation and lead chops the throttle. All I can do then is sail on by.

PM me your number and I'll run up and give you a ride.
 
Longer takeoff runs

I've been flying for about four years in my 6A behind a FP Sensenich on an 0320. I wish the ground adjustable Sensenich had been available when I was making the prop decision. Takeoff runs can be over 1200' when I'm heavy on a hot day, and initial climb is slow due to 2100 to 2200 rpm engine speed. I think a little finer pitch would be much better but you're limited to 2600rpm at the top end with the aluminum FP. John
 
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We fly superbly designed, high performance airplanes.

They cost a lot of money to build........ But !

If you invest 5 years of sweat and toil to build your dream machine, wouldn't you want the best ?

I have flown FP and C/S, there is no comparison.

C/S gives you a gearbox to play with, it gives you flexibility and even more grin than the adverts show ( sorry, we have an MT which is awesome )

You are building an RV7, a truly great airplane. A 180hp fuel injected c/s installation will satisfy every need you want, especially if you want to do aerobatics.

Set power, go stunting - simple.

FP - worry about overspeed, wait for recovery time etc etc.

It is a lot of money, but find a buddy who has one and enjoy the Whooooa !
 
Not to mention, there is a whole page (cant remember the chapter) in Van's preview plans where they recommend the CS prop for all the reasons mentioned above. I look at it as tge cost of doing business.
 
CS initial rate of climb is greater until about 125 knots where CS and FP both perform comparably. CS gives better braking for formation flying. CS are heavier by about 40 pounds on the nose adversely affecting cg and handling. CS has a higher initial cost and higher continuing maintenance costs.
A composite FP like a Catto will run considerably smoother with noticeably less vibration than a CS. A FP has lighter weight for more favorable handling which accentuates the sport flying qualities of the design and a better cg. A Catto is as fast or faster than a CS. For the small percentage of the flight when accelerating to 125 knots on takeoff a FP may be limited to only 2000 ft per minute climb rate.
My flying is sport flying with occasional cross country. I built it light to keep it agile. My Catto suits this type of flying quite well. If you want to fly a lot of formation or primarily fly cross country, CS may suit you better.
Vans recommendation was build it light and keep it simple
 
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to prime or not to prime?

As has ben said above there or a lot of styles of flying, needs to fill while flying, and configurations of aircraft and engine power out there. I agree, picking a prop is one of those things you just have to do a lot of home-work on and then have a long honest talk with yourself over. As Brad mentioned and Van's has set out. Keeping the weight down is a good thing to try and do while building an "RV". There are good merits to both F.P. and C.S. some of each are lite and some of each or heavy. In general there is more hardware that is used to install a C.S. so you will be building that into you W.& B. figures. We have found F.P. props that can out preform some of the high end C.S. props for a lot less that we had expected. As has also been said if you are going to fly Aero or Formation a C.S. has an edge over most of the F. P. props, but again we have found that there are some guys and props out there that can and do work well in Areo or Fromation flying. We like to fly in flights of two, three or four when we can but do very little Areo, so we are very happy with a F.P. carbon over wood prop that weight only about 12 Lbs.
This lets us take 792 Lbs. useable into the air by the book and cart it a long ways or load light with half fuel and go have some fun. Again this is our flight style, yours may be a different matter. Yours, R.E.A. III #80888
 
pilot28906 said:
I am narrowing down on an engine solution (IO-360 180HP) so am now looking at props.

Am I reading this correct?

Hartzell CS: $7775 Sench FP: $3675
FWF Kit: $5750 FWF Kit: $3825
Total: $13,525 Total: $7500

Cost delta for CS vs FP: $6,025

Is this correct?

Is the CS really worth $6K? I understand the difference but that is a lot of $.
Click to expand...

Short answer - yes.

I put a FP prop my 180hp RV-8A, flew it for 300 hours and it did everything expected of the set up. I replaced the FP prop with a Hartzell BA prop and had a totally new airplane. My only regret was not having this CS prop for the first 300 hours.

If you just fly the $100 hamburger missions and such it make little difference what engine and prop you select. The mission for my RVs has always been high efficiency cross country. Considinering the speed range on the RV, achieving this objective is only practical with a CS prop.

Make a mission choice and build on.
Carl
 
pilot28906 said:
I am narrowing down on an engine solution (IO-360 180HP) so am now looking at props.

Am I reading this correct?

Hartzell CS: $7775 Sench FP: $3675
FWF Kit: $5750 FWF Kit: $3825
Total: $13,525 Total: $7500

Cost delta for CS vs FP: $6,025

Is this correct?

Is the CS really worth $6K? I understand the difference but that is a lot of $.
Click to expand...

Probably, like already said, depends on your expected mission/use.

The CS will allow greater control of power and engine speed with various cruise altitudes. And therefore fuel burn. Others should have some good data. If you save .75 gal/hr, your cost (capital+fuel) at 2000 hrs could be equal.

I see you have a -7 - lower weight may not be your friend - 7's tend to be a touch tail heavy due to design for the angle valve engine. You may want to do some research on that one. It would be unhappy to add weight (if FP) for this later.

All said, you can always install the CS later if 1st flight and $ are the focus.
 
Thanks for all the great input and all are good points I am considering. Mission will be fairly local flights with most cross countries under 200 miles with an occasional one up to 500. I have little interest in formation (for now) but am interested in doing aero but only at the gentlemen's level. Or at least this is how I see it now but could change in the future. Anyone with experience doing aero with a FP and your thoughts on controlling speed?


Thanks,
 
Loops, rolls, spins, wingovers and chandelles are no problem with a fixed pitch. I keep positive g's just to keep the belly clean. I don't do snap rolls, but the plane is capable. A long down line is not intentionally in my future either. But these are great planes for aerobatics with FP.
 
In that case make sure you have fuel injection.....

Carbs stop the prop at the most inappropriate moment ;)
 
I love my CS prop for my RV6. I love my FP prop for my Bucker. As mentioned, different missions.
I think your numbers are reasonable if they included the adaptor and governor.

However, the single most expensive maintenance item on my RV6 has been the CS Prop. The typical CS prop not only carries a TBO, many carry a calendar time for rebuild. This is often simply ignored.
Many Governors do too, also often ignored. But hey, many ignore the calendar time on hoses too. Don't want the discussion to go down that rabbit hole, but something to consider.

Although not a big deal, it isn't just the weight of the prop. You have an adaptor, a governor, cable, some oil, and another hose. Not much, but a few pounds added FFW in addition to the Prop.

With all choices, there are many things to consider. I love the CS prop, but I prefer the feel of the FP in handling.

For Aero, the CS you set power and forget it. With the FP, you just have to manage your power. I find FP to be very intuitive and it seems to help with my timing like when to unload etc.... you get some feedback you don't get with a CS prop.

As you are looking at products, look closely at weight and TBO both hours and calendar. This can make a difference in your cost to own vs initial purchase.

There is no wrong choice.
 
JonJay said:
With all choices, there are many things to consider. I love the CS prop, but I prefer the feel of the FP in handling.

For Aero, the CS you set power and forget it. With the FP, you just have to manage your power.
Click to expand...


I am not selectively removing stuff, just leaving stuff I want to comment on.


Determine your normal mission.

Aeros - Constant Speed

Plain touring - FP - it's OK, we won't say anything....

General fun etc etc - Constant Speed

Threepence well spent....:cool:
 
One quick note: The discussion to this point makes the assumption that CS will always be significantly heavier than FP, but this isn't necessarily true. The lightest option will undoubtedly be a FP composite prop like a Catto or Prince, and the heaviest will undoubtedly be a metal blade CS like the BA Hartzell. However, a WhirlWind composite CS, a Hartzell composite CS, or a set of GT Propeller wood/composite blades retrofitted on a Hartzell hub are very close in weight to the Sensenich aluminum FP that so many of us have, so the the presumed CS weight penalty and associated CG issues are not a given.

Something to keep in mind, and which may make the option of trying the Sensenich first and perhaps converting to CS at a later date a more viable and less disruptive possibility.
 
If the original question was about cost, then how about used? when I started the build I wanted that cool 50K engine prop setup but at the end, a lot of funds where used up, so I started looking for a nice used setup, found a 200HP angle valve 250 Hr SMOH and a CS Hartzell with new hub for 16 K. CG allows full 100 Lb baggage if needed.
 
One data point

I don't fly formation, or aerobatics of course (my plane is a -9A). I bought my -9A used, with the Hartzell installed by the builder. I love the CS prop, but it hasn't bit me for maintenance yet, either.

I think I could be perfectly happy with a FP on the 9A. The performance gains of the 9A over my trusty Piper Warrior are so astoundingly massive that I suspect a reduced climb wouldn't remove my grin. :)

In any event, if I were building a 9 or 9A, had a limited budget (most of us do), and didn't want to do aerobatics or formation, I'd probably put the money into avionics and paint rather than the CS.

Certainly reasonable people can differ -- and I know so little about formation and aerobatics that I may be wrong about that as well!
 
I'm running the Whirlwind on my 9A, and the weight is much less an issue than with some others. The price is a little higher but you are trading dollars for pounds to get the carbon-fiber composite prop. I moved my battery aft of the baggage firewall and my CG is just fine. As for the performance, I wouldn't trade it for anything. Takeoff rolls are SHORT short, initial climbs solo with full tanks are 2000 fpm easily, and deceleration on a steep final is quite nice.

It's ultimately a builders individual choice - but in my opinion it's not much of a choice. I'll never run a FP again.
 
It looks like Hartzell requires an overhaul at 6 years or 2400 hours, whichever comes first. One internet search came up with an average cost of $3000. Is this accurate?

Whirlwind props have a teardown requirement, but they avoid saying what the interval is and instead refer you to the documentation that came with the prop. A quick search did not turn up an estimated cost either. Anybody know the teardown time period and cost? WW also lists a non continuous operating limitation between 2060 and 2300 rpm's and 2600 to 2700 rpm's.

MT props appear to require overhaul at 2400 hours or 72 months whichever comes first. But it varies depending on engine application. Anybody know the cost of overhaul?
 
Choices

pilot28906 said:
I am narrowing down on an engine solution (IO-360 180HP) so am now looking at props.

Am I reading this correct?

Hartzell CS: $7775 Sench FP: $3675
FWF Kit: $5750 FWF Kit: $3825
Total: $13,525 Total: $7500

Cost delta for CS vs FP: $6,025

Is this correct?

Is the CS really worth $6K? I understand the difference but that is a lot of $.
Click to expand...


John:
I see you're a CFII and MEI. First, the differential is about right. If you've got a wide budget, who wouldn't want more performance? On the other hand, if I was weighing a CS prop against say an SL30 vs. a GTN, I'd opt for the enhanced instrument capability. Then again, I use my plane for travel.
Too many choices and not enough $$$.

Terry, CFI
RV9A N323TP
 
brad walton said:
Whirlwind props have a teardown requirement, but they avoid saying what the interval is and instead refer you to the documentation that came with the prop. A quick search did not turn up an estimated cost either. Anybody know the teardown time period and cost?
Click to expand...

500 hours. I don't know the typical cost.

As another data point... My metal prop fixed pitch 6A also has an initial climb rate of 2000 FPM when flying full fuel solo.
 
rvbuilder2002 said:
500 hours. I don't know the typical cost.

As another data point... My metal prop fixed pitch 6A also has an initial climb rate of 2000 FPM when flying full fuel solo.
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Scott,

Curious if you have a 360. I have a 320 and only get about 1500-1600 in that configuration in the warmer weather (@2000' MSL).

Larry
 
One more data point regarding formation flying. I have a FP 3 blade Catto. I have recently begun flying with the local Red Star pilots, CJ's and Yaks. After about 20 hours of formation work so far, I have no problems, and neither have my instructors, who are used to the CS props.
 
Thanks all. I know this is a never ending debate. I will be looking for a used CS prop or FP. Love to have it all; new engine, new CS carbon fiber prop, and IFR panel; but budget is a lot smaller. I think in the end the plane will be great with either prop. Thanks again.
 
pilot28906 said:
Thanks all. I know this is a never ending debate. I will be looking for a used CS prop or FP. Love to have it all; new engine, new CS carbon fiber prop, and IFR panel; but budget is a lot smaller. I think in the end the plane will be great with either prop. Thanks again.
Click to expand...

Just a final note - since you opened this thread you can close it if you so desire.
 
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