Whirlwind GA vs Catto 2 blade ??

I'd appreciate all of your input...thx in advance.
Currently have a Sensenich metal 70/79 on my -4 (O320 - 160 HP). I want more/higher maximum cruise speed at my typical 2300-2350 cruise RPM (I don't run higher RPM's because of higher noise levels). Which of these two props would you prefer for my application (higher speed) & why? Also how much increased speed could I expect to gain?

Marvin

At 2300-2350 rpm, I've got my doubts you'll see much difference between the metal Sensenich, a Whirlwind GA, Catto, or even a Sensenich GA prop. They are all very efficient props. The GA props may give you some ability to tune the thrust produced at a given rpm & power setting, but you still have to pitch them to place your static rpms in an acceptable range at full throttle.

Where the Catto and the GA props really shine is above 2600 rpm, when you're getting more horsepower out of the engine.

Next Generation...

autoglide said:

I'd appreciate all of your input...thx in advance.
Currently have a Sensenich metal 70/79 on my -4 (O320 - 160 HP). I want more/higher maximum cruise speed at my typical 2300-2350 cruise RPM (I don't run higher RPM's because of higher noise levels). Which of these two props would you prefer for my application (higher speed) & why? Also how much increased speed could I expect to gain?

Marvin

Click to expand...

Marv,
Neal is spot-on. I will add that THE most efficient prop at lower RPM is the Constant Speed. Where FP props perform best is mid-higher RPM where the mid-lower portion of the blade really starts biting. (blade tip is performing best during takeoff)
Craig Catto nailed this "sweet spot" on his Next Gen props he currently produces. My RVX 0-360J "sweet spot" was 2400 RPM for 150KIAS at 7GPH. At 2550 I was getting maximum performance even though it would turn up to 2700 with a 2% gain between 2550 and 2700.
The WW GA prop has the advantage of being adjustable to set this sweet spot yourself with experimentation.

Either way getting rid of the Sensy Metal is a home run for three reasons:
1. Less weight and flywheel effect.
2. No 2600 RPM restriction.
3. Aerobatics and smoothness.

Both the CC and WW are great improvements, I lean toward the Catto as I have known Craig for 25 years and tested his first RV prop on my RV4. They (his daughters too) are a class act...

V/R
Smokey

Props

As a side note some addl. info:

1. Don't want a constant speed prop
2. At 7000' + will probably turn 2400-2500 RPM in cruise
3. Leaning towards a GA for reasons that Smokyray described

Marvin

WW GA

I have a WWGA for my -8 but I'm not far enough along building to test it so I can't supply any flight data.
Prop is beautiful as is the spinner that came with it. Cattos are too. I considered a Catto three blade but the cost of shipping back/return in case of a pitch adjustment was just too much.
Bill

The Sensenich GA prop is a great performer too, and much easier to set the blade pitch using the pitch pin tools that come with the prop. However it is significantly more expensive than the WW, and with the special carbon fiber spinner, costs almost identical to a 3-blade Catto with metal leading edges, custom paint and spinner. If I could go back and do it again, I'd probably buy a sexy 3 blade Catto instead, but I needed my plane back in the air quickly and back in 2013 there was a very long wait for Catto props and the Sensenich GA was available for immediate shipping.

If you've got the extra money, I'd take a hard look into the 3 blade Catto... they sure look and perform great on an RV-4.

Ordered my 3 blade, nickel leading edge, spinner kit, painted to match catto prop yesterday. $4400. 6 weeks lead time.

I ordered a WW GAP when they first came out and thought it was beautiful; however, at that time, they were only set up for the O-320 bolt size so I returned it and ordered a Catto.

The Sensenich GAP is also a nice looking prop but my neighbor has had a number of issues with his, which is mounted to an O-200 powered Cub-alike. It was so stiff it kept chewing up his mags. In a 120 hours he went through three mags so he sold it.

He now flies behind a Catto, which he loves.

autoglide said:

I'd appreciate all of your input...thx in advance.
Currently have a Sensenich metal 70/79 on my -4 (O320 - 160 HP). I want more/higher maximum cruise speed at my typical 2300-2350 cruise RPM (I don't run higher RPM's because of higher noise levels). Which of these two props would you prefer for my application (higher speed) & why? Also how much increased speed could I expect to gain?

Marvin

Click to expand...

Before you make the change, if the ONLY reason is speed at 2300-2350 RPM, have you done a FULL comparison of the alternatives at that RPM?

The metal Sensi often does not get due credit because of other more-important-to-some features.

All of the recommended props are great. Have flown behind them all as well. BUT !!!!!! A friend of mine was flying next to me with his metal Sensi and I even had a CS and he was doing just fine.

As others mention, the higher RPM is where you the extra speed for the most part on the others.

Just food for thought.

James

Sensi GA prop

I have used the metal prop, a catto 2 blade, and now the GA prop.

They all performed well for mission they were made for. The only complaint i have about the GA prop is that you cant get pitch 8 or 9 with out having the alignment pin relocated..
My 0320 rv4 need just a bit more bite
Cm

autoglide said:

I'd appreciate all of your input...thx in advance.
Currently have a Sensenich metal 70/79 on my -4 (O320 - 160 HP). I want more/higher maximum cruise speed at my typical 2300-2350 cruise RPM (I don't run higher RPM's because of higher noise levels). Which of these two props would you prefer for my application (higher speed) & why? Also how much increased speed could I expect to gain?

Marvin

Click to expand...

I don't think you'll get a higher cruise speed at that RPM than you will with a properly pitched metal Sensenich. Those are very efficient props due to their thin airfoil. They also don't need to be re-torqued, and don't erode in the rain.

To help the commentary, what is your typical cruise altitude, and what manifold pressure do you normally see at that altitude and RPM? Without this information, it is difficult to tell if your prop is correctly pitched for your intended mission.

I installed the WW GA prop on my RV-4 o-320 160hp about a year ago. Have about 75 hours on it now and am very pleased with it. It does take a while to master setting the blade angle. I have probably reset my angle 5 or 6 times trying different settings. I use an app on my iPhone to set the angle. Have been thru a few rain showers and the prop still looks like new.

Performance figures

Tommy

I am in the process of rebuilding my 9A and am likely to use my Sensenich from y RV 4 on it in which case I will be looking for anew prop for the 4.
I like the Catto and the whirlwind seems interesting. So some performance figures would be helpful.

What cruise are you seeing at 22, 23, 24, 25, 26 ,2700 RPM. What climb rate at say 120 MPH. These are things that will help me and people like me to decide which prop to go for.

Thanks in advance.