[bret]

I am still on the fence to go FP or CS prop, some day I will finish my 7 and I want to go with 200-230 HP. Can anyone give me some rate of climb #s in their FP and CS aircraft. I know CS will climb better but trying to justify the 10-15K added cost to the project. Thanks.

 

[DanH]

I am still on the fence to go FP or CS prop, some day I will finish my 7 and I want to go with 200-230 HP. Can anyone give me some rate of climb #s in their FP and CS aircraft. I know CS will climb better but trying to justify the 10-15K added cost to the project. Thanks.

Put a Hartzell BA on it...bulletproof and doesn't cost 10-15K.

 

[Neal@F14]

Put a Hartzell BA on it...bulletproof and doesn't cost 10-15K.

This.

The BA prop for a 180-200hp is $6980 from Vans.
The prop governor is $1250
You've gonna buy a spinner kit anyway no matter FP or CS prop.
Add in a couple hundred more for cables, brackets, misc hardware.

$8500-8700 ballpark cost.

If I had the money, I'd convert my RV-6 in a heartbeat, and I've only got 160hp on the nose (could use some more weight up front anyway).

 

[jjconstant]

...and SUBTRACT the cost of the fixed pitch to get the actual difference in cost. $1650 for a 3 bladed Catto for an IO-360, so realistically it's a ballpark of 7K$ additional. WAAAAY less than 10-15K$ "added" to the cost of the project

 

[Neal@F14]

...and SUBTRACT the cost of the fixed pitch to get the actual difference in cost. $1650 for a 3 bladed Catto for an IO-360, so realistically it's a ballpark of 7K$ additional. WAAAAY less than 10-15K$ "added" to the cost of the project

Very good point indeed.

 

[RV7ator]

Don't forget the superior loadability of a Hartzell out front vs. anything lighter. The more forward empty c.g. lets you put more pig iron in the baggage area.

When FP friends ride in my Hartzell-equipped -7, the usual comment is something like, "This thing's a rocket!". Numbers will be tough to normalize because FP may not all be the same pitch, yet the seat-of-the-pants difference from a CS is very obvious. Broadly, the CS is turning 2700 rpm, the FP maybe 23-2400 at Vy, that's that much less horsepower.

For my pricy opinion I ask why are you leaning toward performance with 200-230 hp, then hobbling the engine with a FP? That's quite a concept dissonance.

John Siebold

 

[gtmule]

Solo, full fuel, i show about 1500 fpm at 100-150 mph. 180 hp carbed 7 with metal fp...

 

[n5lp]

I find that people rarely leave the CS prop at 2700 RPM for long. When it comes back to 2400 the CS and FP perform about the same. So what is that, one minute per flight or so? Well worth it for some and there are other CS advantages but for me, I have been able to hold out when I look at what that one minute a flight would cost me.

 

[mosquito]

Three Bladed Catto is $2150

...and SUBTRACT the cost of the fixed pitch to get the actual difference in cost. $1650 for a 3 bladed Catto for an IO-360, so realistically it's a ballpark of 7K$ additional. WAAAAY less than 10-15K$ "added" to the cost of the project

A new three bladed Catto is $2150, two blades are $1650. I've seen the old price on the website, but I have this on pretty good authority. You're also going to want the nickel leading edges, at $200/blade, so you're at $2750. The gap narrows... Personally, I'd have gone CS by now were it possible w/my O-320.

-jon

 

[hydroguy2]

during the winter I see >2400fpm at 100kts, 1/2 tanks and solo. 190hp 360

coming home from Osh2012, Mobridge, SD it was 97*F and we were FULL! max weight. I was still showing 1200fpm+ climbing through 8500' (>10000'DA)

BTW-I leave my prop all the way in quite often.

 

[plehrke]

Can anyone give me some rate of climb #s in their FP and CS aircraft. .

I have not seen anyone post number yet, just opinions. Here is a link to a thread where several of us actually did some testing to compare numbers. Will not stand up to an engineer review at my company but pretty good. And it is numbers you asked for. See post #39 for some results.

 

[bret]

Join Date: Dec 2006
Location: Arroyo Grande, CA
Posts: 938

Quote:
Originally Posted by Ron Lee
David, I fly with CS RVs (180 HP) a lot. They perform far better than my FP prop with 180 HP.

A CS prop performs better than a FP prop. I don't need numbers. I see it often in side by side climbs.
Here's the real skinny for what it's worth. A properly designed, high efficiency FP will always have the efficiency edge on a CS because any CS now available will not have as good an efficiency as the FP; a CS has more loss in the root and tip region. In a climb at low speed the CS will always be less efficient than a good FP, but it has the advantage that it can give rated rpm for more power, and it is excess power over what is needed for the drag that is used to climb. Both FP and CS props suffer in a climb from low mass flow due to low forward speed which keeps their efficiency to 75%-80%. If your FP prop at best climb speed turns 2400 rpm vs 2700 rpm rated, your power will be down to 89%. But if you put in a 180 for your 160, you get that back and you will actually climb better than the 160 CS at rated rpm! So, which costs more in the long run? A 160 with a CS or a 180 with an FP, and which has better all-around performance?

This makes sense to me, is he wrong? Runway length is not an issue for me, but where I depart from is cradled by the Sierra Nevada Mt. Range, so my question is, can I get away with a simple FP 3 Blade, or do you think I will be happier going CS prop. Most of my air will be a jump from 4500 to 12,500 ish within 7nm. Thanks again for the help here.

 

[airguy]

I find that people rarely leave the CS prop at 2700 RPM for long. When it comes back to 2400 the CS and FP perform about the same. So what is that, one minute per flight or so? Well worth it for some and there are other CS advantages but for me, I have been able to hold out when I look at what that one minute a flight would cost me.

The CS prop really shines during high cruise - which not everybody does.

 

[PerfTech]

Love Those C/S Props!!!!

...I love my Whirlwind C/S propeller. Shorter take offs, far better climb, better economy, RPM selectable for less vibration or noise, and it really goes fast up high. As for numbers, my home airport (KREI) is 1500' high, my 9-A with me @ 280 lb. and full fuel on standard day will climb at 2400 FPM with 1200 FPM @ 10,500 ft. also love the braking I get from the C/S in the pattern that makes approaches or formation work much nicer. Thanks, Allan...