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how to pick a prop? value & other considerations?

flyboy1963

flyboy1963

Well Known Member
Hey guys, at risk of starting another thread, this may actually be informative for existing AND builders who have yet to buy a prop.
there are 100 threads on props, but I'd like to see if someone can share their research on this.
for example: If someone has a 150 hp Lyc., and wanted a prop for a -7, what were the choices?
fixed pitch:
hartzell wood $2000
sense wood $1100
Prince wood/comp $2000

Sense metal $2500
Hatzell metal $3000

ground adjustable:
Ivo $3000
Whirlwind $5000

you get the drift....

personally i have a Sense fixed, and love the low maintenance and long TBO, but of course, wonder if I had one inch less pitch if it would spin up better and give me more overall performance!

there.....I've kicked the nest...let's see what comes out! :)
 
Catto is the way to go ...

Catto props have spectacular performance and you'll pay no more (or even less0 than you would a "standard brand" prop. Personally, I wouldn't go any other way.
 
really? no-one has done this?

Nate, you win the prize for being first to do exactly what I feared.:)
I am looking for someone who has some numbers to share with all of us, from their research.
I HAVEN'T DONE IT! these are NOT real prices, just an example of what I'd like to do if I had, oh, say, a bit more free time.
thanks
 
Sterba

A Sterba fixed pitch wood prop was less than $600 last time I checked. If you're not really sure what you'll want ultimately or if you're running out of money and just want to get into the air, seems like a great option to me.

How long does it take to change a prop? At that price, it wouldn't be out of the question to have one pitched for climb and one pitched for cruise and change them out depending on the mission.
 
flyboy1963 said:
personally i have a Sense fixed, and love the low maintenance and long TBO, but of course, wonder if I had one inch less pitch if it would spin up better and give me more overall performance
Click to expand...

Seems like all the Sensenich fixed pitch metal props for all O-320 equipped RVs have the 2600 RPM limitation, which may be a problem if you want to want to "spin up better". Their metal prop offerings for 180hp O-360, and 118hp O-235 engines on RVs don't have that RPM restriction.

See their application guide here: http://www.sensenich.com/files/docu...luminum_Propeller_Applications_1266529729.pdf
 
painless said:
+1. Extremely happy Catto owner here.
Click to expand...

If I were looking for another prop, I would likely get a 3 blade Catto prop. I loved that prop - smooth, good climb (not as good as constant speed but still good), good cruise, etc.
I would insist on the metal leading edge option though. I have a Catto prop hanging on the wall in my garage because the leading edge did not hold up to the abuse my type of flying would subject it to.
 
Can anyone shed some light on some "real" performance numbers with a Catto / O-360 combo in a RV6 or 7 ?

I own a Sterba, and I can assure anyone that the price shouldn't let you build a negative opinion of it. It's very smooth, I get Van's published performance numbers dead on. Also, a wood prop as a way of bending and flexing that is very diffferent than a metal or composite one... At higher speed, it feels like it adjust itself to the power setting almost as a CS speed prop would do...

But, I've heard a great deal of satisfied Catto owners and would really like to compare numbers. Real numbers that is! :D Often, when people pay much more, they instinctly feel like their getting much more... not always the case!!
 
lockeed said:
Can anyone shed some light on some "real" performance numbers with a Catto / O-360 combo in a RV6 or 7 ?

I own a Sterba, and I can assure anyone that the price shouldn't let you build a negative opinion of it. It's very smooth, I get Van's published performance numbers dead on. Also, a wood prop as a way of bending and flexing that is very diffferent than a metal or composite one... At higher speed, it feels like it adjust itself to the power setting almost as a CS speed prop would do...

But, I've heard a great deal of satisfied Catto owners and would really like to compare numbers. Real numbers that is! :D Often, when people pay much more, they instinctly feel like their getting much more... not always the case!!
Click to expand...

I don't have a RV but I did go from a wood 2 blade to a Catto 3 blade in my plane. My takeoff and climb was noticeably and significantly improved with the Catto. At the same time, my cruise speed increased around 5 knots.
I feel sure you would experience similar results in your application.
I wouldn't pull a perfectly good wood prop expecting to see tremendous gains in performance. If my wood prop was showing signs of imbalance though, now that is another matter and I would go a shoppin for a Catto.
 
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lockeed said:
Can anyone shed some light on some "real" performance numbers with a Catto / O-360 combo in a RV6 or 7 ?

I own a Sterba, and I can assure anyone that the price shouldn't let you build a negative opinion of it. It's very smooth, I get Van's published performance numbers dead on. Also, a wood prop as a way of bending and flexing that is very diffferent than a metal or composite one... At higher speed, it feels like it adjust itself to the power setting almost as a CS speed prop would do...

But, I've heard a great deal of satisfied Catto owners and would really like to compare numbers. Real numbers that is! :D Often, when people pay much more, they instinctly feel like their getting much more... not always the case!!
Click to expand...

Real numbers for you.

I TAS 150kts
I must pull RPM back to 2200 MAX in rain.
I have around 100 hrs on my 3 blade, and im now seeing lots of stone chips. I have the leading edge tape. ( well whats left of it )
I feel im a little slow to other rv7s in my area.
its not much fun with a 3 blade when you have to pull the cowls off. always one blade in the way.
It looks cool ! :)
Watch your CofG if building a "A" model, I had to use a steal crush plate.
go with saber for prop extension.
Over all im happy with Catto.
 
Sensenich to Catto

There's a problem when making general comparisons in prop performance from brand-to-brand - You can't just say "Catto props will perform better than Sensenich" without publishing blade specs (pitch and diameter).

I'm installing a new Catto 3-blade today in place of my wood Sen prop.

I have detailed performance numbers for the wood prop and will conduct the same tests with the Catto and plot results and post.

I'm not concerned about how much I spent and will not let the $ get in the way of the truth. I'll use a referred weight method of obtaining the data which accounts for DA and weight and assures an apples-to-apples comparison of the data.

Data I'll provide:
Prop specs
Weight
Cost
Time from order to delivery
Static RPM
Ground Acceleration to V1
Steady State ROC at Vy
Steady State ROD at Vg
Power Required vs Airspeed (the difference from prop to prop will be a measure of prop efficiency for the same W/delta)
Qualitative assessment of vibration
Qualitative assessment of cowl installation/removal
Qualitative assessment of cool factor (judged through a woman's POV)
 
I have to say Catto does make a good prop but his production line to RV'ers has really slowed down since the Cub Crafter deal was put together. I've been waiting a LONGGGGGGG time. :(
 
If you were to buy a Sterba or something else inexpensive to get in the air and wanted to upgrade to a 3-blade Catto later, would you be able to use the same Saber extension and crush plate? Something to consider if you want to get in the air cheaply now.
 
Yes, I'm a bit biased but, Performance Propellers USA is an excellent choice for either a Two blade or Three blade Multi-laminate Propeller. Great Price and fantastic performance and personalized service. Performance is customized for what you want out of your plane.
 
Some Numbers!!!!!!!

Tested 2/24/2011 on my RV-9A
Catto Three Blade/Nickel Edge

Just finished flying the new 68x70.
Here are the numbers.
This is on a stock RV-9A, 171hp,
1556lb takeoff weight.

Full throttle static rpm at brake release 2168 RPM
RPM at 60kt liftoff 2255 RPM
110kt Climb rpm 2365 RPM

Initial climb rates 1575 FPM

Climb rate going through 5000 1350 FPM

Again my RV is a bit fast, 171 KTS
This was max at 5000’. @ 2910 RPM


Throttle pulled back to 2700rpm – 163kts
2600rpm – 155kts
2500rpm – 149kts
2400rpm – 144kts
Hope this helps.:D
 
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great feedback! keep it coming.....

Allan, I'd kill for performance like that.........

Sensenich metal - 70x79.

stock RV-9A, 150hp, (maybe.)
1500lb typical single pilot loaded weight.

Full throttle static rpm at brake release 2150 RPM

Initial climb rate 975 FPM @ 90 kts aprox.

150 KTS max at 5500’. @ 2400 RPM WOT
speed from GPS only on a calm standard day.
 
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Bang for the buck. . .Sterba

I had an Aymar Demuth prop come apart almost 3 years ago shortly after I bought my Rv6a. No one could get me a prop quickly except for Ed Sterba.

He made me a prop and had it shipped within 2 weeks and it cost me $650 including shipping !!!!

It was at least a third the cost of any comparable wood prop, has a leading edge protection, and looks very nice.

It is a 70" by 86" and to be honest is a little overpitched. My plane has old wheel pants, and antennas sticking out everywhere.

At 8000ft and WOT I get 156kts to 160kts depending on whether loaded with two adults and full fuel or solo and half tanks. Thats turning 2530rpm WOT and burning about 8.5gph leaned. I never had Ed repitch since almost all my flying is a few thousand feet, 2100rpm, 130kts and burning about 5gph. My personal favorite sweet spot.

I have saved and am upgrading to a Catto two blade, carbon composite overlaid, and metal leading edge. Im also getting a matched spinner, cut, trued, and painted to match prop for $272. Thats less than half of the price of an unpainted matched spinner from one of the other wood prop makers.

Im getting the advantages of a wood prop but in a rain ready IFR prop and the spinner painted ready to bolt on for under $2500. If it performs as well as it looks. .. Ill be happy.

Value, if your wanting a wood prop, I cant imagine a better value than Ed Sterba's.
 
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