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Which would you pick ?

D

Darren S

Well Known Member
I know this issue has been discussed at lengths in the past but I still am having difficulty deciding which road to take. Maybe others opinions will help clarify the issue for me.

I have a choice of getting an #1 :O-360 with C/S or #2: IO-360 with Fixed Pitch.
The IO is 180 HP.

As we know, advantages of #1: pitch variability, fuel economy, aerobatic downlines,
disadvantages : weight, cost, maintenance

advantages of #2: no carb heat, easy/reliable start, fuel economy, weight, simplicity
disadvantages: aerobatic downline overspeeding

The C/S option is about $ 2000 more. Which would you pick ?

Darren
 
The one you want.

Every time I've had a choice like that I knew which one I really wanted all along and ended up spending all kinds of time trying to justify it to myself and/or my wife. Pick what you really want and be happy.

Good Luck,
 
CS for sure

Darren, I would go with the CS prop for sure. You can back the RPM down during cruise while keeping full throttle and that makes for a MUCH nicer cruise experience. Quieter, and more efficient. I've flown both props extensively, and that's my take...
 
Bill Wightman said:
Darren, I would go with the CS prop for sure. You can back the RPM down during cruise while keeping full throttle and that makes for a MUCH nicer cruise experience. Quieter, and more efficient. I've flown both props extensively, and that's my take...
Click to expand...

Mine too. But then I've repeated it many times here! I MUST have a C/S prop, unless it's for something such as flying a single seat RV3 around the airport area once or twice a week. Then a cute little wood prop would do! :D

L.Adamson --- RV6A (flying)
 
Thanks for the answers,

Craig, you hit the nail on the head. I better pass on the IO and go with the C/S as it's what I really WANT and will use every time I fly. I can compromise and save the $2000 but always wonder in the back of my mind how she might fly with a C/S prop. And this particular IO doesn't have the capability to convert to a C/S later.

Thanks again,

Darren
 
I went C/S too.

I went the same way. I got the Whirlwind 200RV and have been happy with my choice (although I haven't flown it yet). I like the weight savings.

Take care,
 
CG? & Gross Weight?

Darren,

I did not see any concern for CG or gross weight? What are you building?

I have an RV6 with a Mattituck O-360 turning a Catto 3-Blade prop. I REALLY love how smooth the prop is and it looks COOL! I do think at some point I will convert to some form of three blade CS because I would like to move the CG forward. The extra weight total is a non-issue for my configuration.
 
Ain't necessarily so

robertahegy said:
C/S Prop for sure. Actually the carby is easier to hot start.

Roberta
Click to expand...


The AFP FI system uses a purge valve (which you could fit to the bendix system as well)..Using the urge I've not had any harder time hot starting than with a carb.

Frank
 
suggestion on best place to get C/S units

Any suggestions on the best place to get a C/S governor, prop and associated hardware. I know Van's sells some, but was wondering if there are other places.

I don't have an engine yet. It's a -7 I'm building and will likely go with an O-360. The mount is a Dynafocal.

Thanks,

Darren
 
I've changed my mind yet again :) I'm usually a pretty decisive person but this C/S vs. FP issue has me in a knot. I know I'm not the first !

I read some good thing about Catto props. Not sure yet about 2 blade or 3 blade, but I think a good combo for my RV-7 will be....... IO-360 (180 HP) and Catto FP prop.

For $2K, a quiet, low maintenance prop seems to fit the bill better than $9K for a C/S. My airfield is at 3400 ASL, runways are 2400 feet.

I know the take off and climb out will be a bit less than the C/S but weight savings and simplicity is winning out. This is my thoughts at the moment.

If anyone sees a major flaw with my thinking then please chime in :)

Thanks,

Darren
 
You will get a LOT of people saying that you NEED a C/S prop. It just ain't so! If you want a C/S they are great. But certainly not necessary. I've been running a F/P on my -6 for over 16 years and love it. I fly out of a 1500' strip in Texas and have flown many times out of Colorado airports, including Leadville, with no problems.
I have a 3-blade Catto and love it.
 
Consider the importance of slowing down

I picked an O-360 and FP cruise Sensenich for my 9A. I get 1200 fpm climb from a 3000 msl airport with full fuel. For my xc 400 mile runs, fp is perfectly suitable. However, cs gives you the ability to slow down a lot better than my fp. Recently, my friend took me for a ride in his IO-360 CS RV6A. We approached final at almost twice the speed I usually arrive with, but he changed the pitch and it felt like speed brakes.

Obviously, CS is the best of both worlds. If a cruise fp is your choice, learn to slow down a lot sooner or get good at slipping the airplane.

Barry
 
This is probably debated to death elsewhere, but I'll get current opinions anyways. These Catto props seem, from what I've been reading, to be a smooth running, decently priced FP prop.

Three blades are only advantageous for ground clearance ?
They are lighter than metal so a big nose weight is needed to keep CG in check?
They are custom made to suit a builders cruise performance needs ?

I'm building a -7 so these are some things I wondered.

What are the disadvantages ?

Darren
 
Darren S said:
For $2K, a quiet, low maintenance prop seems to fit the bill better than $9K for a C/S. My airfield is at 3400 ASL, runways are 2400 feet.
Click to expand...

A Hartzell is only $6649 instead of $9K. :)
As explained in the last reply, one of the biggest advantages of a C/S is a wide range in controlling airspeed during a landing.

L.Adamson
 
Darren, You'll "get the job done" either way, whether its FP or CS. The RV's acro just fine with a FP on the nose, and I'll point out that on an RV4, the FP keeps the airplane light and in balance which is really important. Allowing the propulsion package to get too heavy kinda ruins the feel, IMHO.

But, the RV7 will handle a CS propeller and stay in balance if built right. It was designed from the get-go for either FP or CS. So, in the end, you just have to list all the variables - pro and con - and make your own decision.

If you want simplicity, the lightest weight, lower cost, and don't care much about some minor performance tradeoffs, I'd recommend FP.

If you want to extract the most performance & efficiency possible, and/or if you place a higher value on short field takeoff/climb performance, the the CS might make more sense. I personally like the CS for a different reason: its great in formation, and pulls the plane through low speed stuff much better. Besides, the WW 200RV looks great. But that will set you back a few more $$...

Either way, pay close attention to how the plane will balance, and be mindful of weight creep.

ps: in my avatar, that's a FP 68-86 Amar-Demuth on the nose of my 4.
 
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