What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Catto props

S

smoke

Active Member
I currently have a fixed pitch sensenich metal prop on my RV8. The cruise speed is very accepable, but the take off and climb is somewhat lacking. Does anyone have any thoughts recomendations on Catto propellors? I am considering a 3 blade that Craig says will greatly improve the low speed with little effect on the top end. Any comments, experience ??
 
I replaced my wood Sensenich with a 3-blade Catto and shortened my takeoff roll by 17% without hurting my cruise at all. My cruise at WOT at 8000' is 201 mph TAS. The engine is MUCH quieter and smoother. My engine is a modified O-320-E3D, 9.5:1 compression and roller rocker arms. It developes approximately 177 hp.
 
Close!

I second Mel.
We have a 3 bl Catto on our 6A with stock 180 HP Lyc and asked Craig to pitch it for max cruise. He asked if we mind running 2700 RPM to which I agreed. Solo we True 204MPH and 202 with two people at 190lbs and 135 lbs at 7500-8000 feet. Smooth as silk and quiet too.

I've experimented with different climb speeds and 135 MPH yields 1900 FPM and 160 still gets over 1000FPM, solo......not too shabby! ;) Even at 2450 RPM we run over 185!
 
Wood not Metal

The Sensenich Mel replaces was wood. Everyone says Catto's props are excellent, but does anyone have a direct comparison between Sensenich metal and Catto?
h
 
If you will go to the Sensenich web page and look at the comparrison between the wood and metal prop on the 180 hp, you will find that the preformance is very close. Martin Sutter did the tests and the wood prop actually had a little better climb.
 
pierre smith said:
asked Craig to pitch it for max cruise.
Click to expand...
What is the pitch on your prop? I asked Craig to under-pitch it just a bit (for better t/o and climb) and I ended up with 76 inches. I can hit 2800RPM down low though at full throttle.
 
The pitch on fixed pitch props is not directly comparable between brands, number of blades or materials. Different props use different airfoils and planforms.
 
True Mel, but we're comparing two 3-blade Cattos made for for O-360/ 180HP RV-6s, so the comparison should be as apples to apples as it gets.
 
smoke said:
Craig is proposing a 66 x 75 - anyone else using this prop? How is your performance?
Click to expand...

My prop won't be shipped for probably another month or so, so this doesn't help you much, but I told Craig that I was looking for best cruise and what he told me was:

Hello,
From the performance that you are expecting, you should easily achieve. The
360 RV-7's are getting close to 1800 feet a minute and top ends of over 210
TAS.
Short field operations usually isn't to much of a concern with the RV's as
their takeoff performance is quite good anyway, especially if your running a
360.

The prop I make for this is my 66 inch diameter three bladed and 76 inch
pitch, but the blade width is a bit more than standard for the dual
electronic ignition. This prop fits Vans finish kit parts for a wood
propeller. Bolts, extension, spinner etc.
Cost of the prop is $1850 and delivery is out 6 months. I am trying to get
that down right now, but hard to make any promises.

Regards,
Craig Catto

I'm accepting Craig's suggestion for going with the 66"/76 pitch and it'll be fun to see if I achieve the performance that he's suggesting I will. That would tickle me to death and vindicate those who say "I don't need no (having to pay $7G for a) steeenking CS prop". :D
 
That sounds about right. I asked for more of a climb prop and I believe that mine is a 66 X 74 with the narrower blade.
 
Pitch

Mornin' all. I recall my pitch to be 76" as well. We use around 500-600 feet for takeoff from pavement but the point is kinda moot since it takes a lot more than that to land on anyway,
 
Cg

Dont forget to account for the CG change with your (hopefully) new Catto prop. It weighs 17-18 lbs... compare that to 42 lbs for the Sensenich (if I recall correctly). You can get a heavy prop spacer to offset the difference or there are weights you can put on the starter ring.

Mine is a 66x76. Still haven't pushed the start button but hopefully that will be not too far off. Craigs props are a work of art. Unfortunately they take a while to obtain.
 
Scott Will said:
Dont forget to account for the CG change with your (hopefully) new Catto prop. It weighs 17-18 lbs... compare that to 42 lbs for the Sensenich (if I recall correctly). You can get a heavy prop spacer to offset the difference or there are weights you can put on the starter ring.

Mine is a 66x76. Still haven't pushed the start button but hopefully that will be not too far off. Craigs props are a work of art. Unfortunately they take a while to obtain.
Click to expand...

Already have that covered. I bought the 1" steel plate from Sabre they make as an option that bolts onto the front of the prop.
My intent is to end up with a weight at the nose that would be similar to a CS prop in order to get the CG right from the get-go. The additional benefit is the added flywheel affect from the weight. I haven't weighed it yet myself, but I think he said it was about 18 to 20 pounds.
 
This may be a stupid ? but do the FP spinners from Vans come without holes cut for the blades? Or, do I have to tell them that I'm going to use a 3- blade catto?
 
You cut your own holes. Not difficult at all. BTW, I recommend that you do this yourself. While Craig will cut them for you, in my opinion, he cuts them too big.
 
Spinner cut out

Hi All
I have a 3 blade Catto on my RV4 and I had Craig cut the spinner out for me. I belive that he save me at least 2 spinners worth of cost. :D
 
Cutouts too big

Mel, I found just the opposite, and I ended up opening up the cutouts a bit. Maybe he's changed his technique over the years?

In any event, I highly recommend making up a set of prop "booties" to slide over the roots and protect the finish when taking the spinner on/ off. I made mine from some leftover UHMW flap tape. Just big enough to slide in between the prop and the spinner where they contact. I don't have a picture handy but it should be easy enough to figure out if you look at it.
 
sprucemoose said:
What is the pitch on your prop? I asked Craig to under-pitch it just a bit (for better t/o and climb) and I ended up with 76 inches. I can hit 2800RPM down low though at full throttle.
Click to expand...


I have the 3 blade 66x76 prop but only obtain 2620-30 rpm down low.
At 8500msl, I'm getting 198 mph 4way gps. I still have no paint and the airframe can still be cleaned up a bit. I suspect I'll pick up another 5mph once clean. I'm running the XP-IO-360 with horizontal induction.
My rpm matches Craig Catto's formula of static + 500.
 
Last edited:
DanLandry said:
I have the 3 blade 66x76 prop but only obtain 2620-30 rpm down low.
At 8500msl, I'm getting 198 mph 4way gps. I still have no paint and the airframe can still be cleaned up a bit. I suspect I'll pick up another 5mph once clean. I'm running the XP-IO-360 with horizontal induction.
My rpm matches Craig Catto's formula of static + 500.
Click to expand...


Update
I stand corrected. I hadn't done any low altitude speed tests since around 40 hours. I'm in the process of cleaning up the cowl and fiberglas in prep for painting and thought I'd do a run at 2000 msl tonight. Craig was right on the money. This is the first time I was able to get 2700rpm wot.

2700rpm wot at 2000msl, DA=3550
192 IAS
203 TAS
205 GPS
16.3gph fuel flow.
 
The only "pitch" that really counts is effective pitch. You get it by TAS(mph) X 1056 / RPM! That formula gives you how many inches forward per revolution you are actually getting. If the prop is pretty efficient, you should obtain the same value +/- 1% over a range of TAS, RPM, and DALT.
 
DanLandry said:
Update
I stand corrected. I hadn't done any low altitude speed tests since around 40 hours. I'm in the process of cleaning up the cowl and fiberglas in prep for painting and thought I'd do a run at 2000 msl tonight. Craig was right on the money. This is the first time I was able to get 2700rpm wot.

2700rpm wot at 2000msl, DA=3550
192 IAS
203 TAS
205 GPS
16.3gph fuel flow.
Click to expand...


Another Update from 8000msl, DA=11300, wot, solo, 20gls autofuel:
Hdg rpm IAS TAS GPS
360 2600 165 196 179
120 2650 178 209 217
240 2600 165 195 193

Ave 169.3 200 196.6

It matches Van's numbers.
Still no paint. Soon...
 
Catto Prop Pro and Con

Pros:
1) It is easier to hold the nose off the ground on landing since the front end is lighter (A friend sold the CS prop off his -6A and installed a 3-blade Catto after bending the nose gear on landing.).
2) If you do screw up a landing, there is more ground clearance.
3) My -9A goes a calibrated 6 mph faster than Van's -9A demo (as determined by CAFE) but a higher RPM.
4) I know of two sixes that gained top speed after installing Catto's, one from a CS and the other from a 2-blade wood prop.
5) Pilot/paggengers have remarked than my plane seems smoother and quieter.

Cons:
1) My Catto has several chips after only 180 hours, and I have only landed on paved strips.
2) It is necessary to reduce the RPM in rain.
3) With less weight on the nose, it is easier to get in an aft CG condition.

Leland
RV9A with an unmodified O320D1A
 
My Catto has zero chips after operating off my 1500' gravel strip for 3 1/2 years.
The secret is to not add full power until after the airplane is moving.
 
2.25" EXTENSION- what size bolts?? for Catto Prop

Is the bolt sizes determined by the engine or the prop?

Is there a "standard" size for Catto 3 blade props for the bolts? Vans has 3 choices on website.
Thanks
 
Bolts

Kind of a multiple answer, but...

The crank will determine the diameter of the bolt per the bushing size.

The type of spacer will determine the bolts you use.

Call Saber MFG. in Grandbury TX and talk to Sam.

You will not be disappointed! :D
 
LifeofReiley said:
Kind of a multiple answer, but...
.......The crank will determine the diameter of the bolt per the bushing size......
Click to expand...


Sort'a, but those bushings are easy to change if need be.

Cheers,
Stein.
 
You must log in or register to reply here.
Back
Top