Fixed pitch (Catto) prop on O-540?

[kestrel]

I was (finally) reading the latest Beartracks and noticed a couple of things. Most important was a splendid picture of 6JC at Bob's fly-in this fall. ;-)

The other thing I noticed was the write-up on Heath Sneller's 4 place Bearhawk. It is equipped with an O-540 and a Catto prop. Since I'm looking for ways to take some weight off my wonderful beast, I'm intrigued by this cunning choice. Is Heath on this forum or can anyone PM me some contact info? Does anyone else have experience with fixed props on O-540's?

I'd be interested in knowing things like:

- full throttle static rpm
- full throttle climb rpm
- rpm/manifold pressure at 55% power in level flight

I typically run about 21-22 "squared" burning 9-10 gph. I'm wondering what cruise a 55% rpm might be like with a prop pitched to not give up much on take-off.

Thanks!
Ty

[X'N]

Shoot markphillips1228 on this forum a pm I believe he may have Heath's info. Sent from my iPad using Tapatalk

[bearhawk2015]

delete......

[tf104]

I have a two blade catto for my o540 , I do not have any performance data as I am still building but I do know that it weighs sixteen pounda and is a work of art.

[kestrel]

Heath, thank you! ...one more question (besides eagerly awaiting more data): What is the HP of your 540? Mine is a 260hp.

tf104, 16 lbs sounds a LOT better than the 54 lbs plus governor of the Hartzell I'm flying now. What is the power rating of your motor?

How did each of you decide on 3 vs. 2 blades?

Since I'm not trying too hard to go fast and generally care more about runway performance, I think I'd lean toward a longer 2 blade?

My bird is 1600lbs empty and heavy on the nose, so I'm looking for ways to shed some pounds up front to improve handling and performance.

[tf104]

250 hp at 2575 rpm I told Craig that I was willing to give up a bit of take off and climb performance for a better economy cruise and he recommended his two blade prop.

[alaskabearhawk]

This may be a silly question, but why on earth would you put a fixed-pitch prop on an O-540? I know you can, but it's like having your transmission on your car stuck in second gear...for as long as you own it.

[tf104]

That's easy, Less cost , less maintenance, lighter weight

[bearhawk2015]

delete.............

[jaredyates]

I got a note from Larry T. in Louisiana after the Beartracks came out. He is running a fixed-pitch Catto on his 4-place with a 360. He pointed out that folks should be sure to check the torque on the mounting bolts at each oil change. His became loose an caused some problems.

[alaskabearhawk]

"That's easy, Less cost , less maintenance, lighter weight" Ok, I can see that. But the question still stands. I can have a car with one gear. Less cost, less maintenance, lighter weight. I know there are crop dusters that have fixed-pitch props, but those are specific for one mission. I guess if you have only one thing in mind it would be ok. It just seems so limiting, especially if you fly any distance.

[tf104]

Please understand this thread was not started as a fixed versus constant speed debate the individual was asking for data on a fixed prop. I went through this about a year ago when I posted the question , all of the constant speed guys came on with how great constant speed props are and none of the fixed pitch guys chimed in.

[bearhawk2015]

delete........

[kestrel]

When comparing the 84" Hartzell constant speed that I have now, an MT may be 10-15 lbs lighter. Changing to a Catto could save nearly 40 lbs. ...that's 40 lbs on a bird that (though I love it dearly!) is both heavy and nose heavy (I'm referencing both weight and balance). Taking 40 lbs off the most forward point of the airplane with a properly matched prop may well improve not only its takeoff performance, but also its landing performance. Since I normally cruise at lower power settings, the only compromise might be a slightly higher rpm in cruise?

Also consider that this airplane gets off the ground and clears trees. It does that without any question! Esp. if trees are a factor, I can get out of MUCH smaller places than I can get in to. ...power does nothing to improve landing performance. Taking weight off the nose not only reduces weight, it also reduces the down force of the elevator which the wings must also carry. Further, an airplane that is nose heavy is harder to manage with power changes as the power causes greater pitch trim changes. Thus, taking weight off the nose will also improve landing consistency. How far you roll after you've burned off extra energy and finished bouncing doesn't matter. What matters is how far you've traveled from the first point of safe touchdown. ...every time, worst case.

So, "yes", I am considering changing out a constant speed for a fixed pitch. I've flow MANY fixed pitch airplanes and they run great! I'm also considering an MT to keep the "full performance" and lose some of the weight. ...or I may never change it at all. If I don't ask, I can't make informed decisions.

[BML1221]

Heath,

Do you still have the fixed pitch Catto on your Bearhawk? If so, after 3 years of use, how are things going with it?