Propeller

[RVCFI]

Considering Sensenich ground adjustable prop. 180hp Lyc. Friend says that the hub will crack? Anyone have any experience with this issuse?

[breister]

Every prop by every maker has had SOME issues, only question is relative reliability. I lost a blade on an Aymar-Demuth, a scenario repeated by many others that seems too common to be acceptable for that single brand. A friend threw a blade on a brand new Hartzell C/S, nearly killed him.

Curious about the choice of a ground adjustable - is it because you found a used one for a good price, or is there another reason for the choice? In the air it is just a fixed pitch, so in theory finding the right fixed pitch would be cheaper and simpler.

[Christopher Murphy]

Originally Posted by RVCFI

Considering Sensenich ground adjustable prop. 180hp Lyc. Friend says that the hub will crack? Anyone have any experience with this issuse?

I have the 160 hp version and I really like it. Not sure why your friend thinks the hub will crack?

Its not just another fixed pitch prop, the blade design , diameter, and the ability to tweak the pitch makes it better and worth the extra cost.

Cm

[gmcjetpilot]

Ground adjustable props have a reputation from the past but not aware of Sensenich having issues. Sensenich is a real propeller manufacture going way back. Their fixed pitch metal props are well respected for RV's.

Ground adjustable props made by small companies in the last 30 years had a lot of issues. Most of these props were made for ultralights, powered parachutes, very low HP engines. Well some prop makers started marketing props for Lycoming, Continental powered experimental aircraft. They did NOT do well, even if they beefed them up. They fell apart. Leave it at that. Not a fan of ground adjustable. I'd suggest you go CS or Fixed. You don't see certified planes with ground adjustable props anymore.

Swapping out a fixed prop can be done in an afternoon. They are not expensive and you could have more than one prop, TO/Climb/General and another for Cruise.

CS Prop, you can pick up a good used Hartzell (not the latest BA but the 7666 bladed one) for $2000-$3000 and an overhauled Woodward Gov for $500-$1000 if you look. Many of the older Hartzell Props are available as people upgrade. If your engine is sold crank well then a good fixed prop is they way I'd go, really light fixed wood or metal Sensenich. Can't go wrong.

[gmcjetpilot]

Ground adjustable props have a reputation from the past but not aware of Sensenich having issues of Gnd adjustable props (but do your research). Sensenich is a real propeller manufacture going way back with a great Rep. Their fixed pitch metal props are well respected for RV's and Certified planes.

Ground adjustable props made by small companies in the last 30 years have had a lot of issues. Most of these props were made for ultralights, powered parachutes, very low HP engines. Well some of them started marketing props for Lycoming, Continental powered experimental aircraft. They did NOT do well. Leave it at that. Not a fan of ground adjustable. Your friend probably remembers the IVO days or other ground adjustable props that could not handle the power pulse from a Lycoming. You don't see certified planes with ground adjustable.

Personally I don't recommend adjustable. Get a fixed prop or spring for a constant speed. Swapping out a fixed prop can be done in an afternoon if you want to "adjust" it. If your engine is sold crank well then a good fixed wood (carbon covered or all composite) Prop or metal Sensenich would be great.

CS Prop, you can pick up a good used Hartzell (not the latest BA but the 7666 bladed one) for $2000-$3000 and a overhauled Woodward Gov for $500-$1000 if you look. Many of the older Hartzell Props are available as people upgrade.

[YellerDaisy]

Originally Posted by RVCFI

Friend says that the hub will crack?

Based on what facts? This is a huge safety issue for some of us - please share.

Originally Posted by RVCFI

Anyone have any experience with this issuse?

~130 hours in front of a 160hp O-320 and no problems yet. Just the opposite in fact, it is incredibly smooth (without dynamic balancing) and I am happy with the performance and adjustability (used when flying high-density altitude and short/backcountry strips).

[steveb]

steve from Sensenich here:
Even with a long gestation with our first RV / Lycoming adjustable pitch propeller, we discovered a very small hub crack many hours after the endurance test, but it was on a fire-breathing high compression electronic ignition engine.
This was a test partner's setup who did a great job of beta-testing it to the hilt.

Some additional finite element study and a minor hub tweak addressed that issue and have since had very good sales and feedback on this two blade adjustable pitch propeller.
Totally agree on the comment that little propellers don't scale up well to the pounding of a big bore direct drive Lycoming;-)

Since then, we took all the lessons learned with the two blade and designed a new three blade 68" diameter propeller which:
-performs as well or better
-is inherently smoother and quieter
-and has great ramp appeal.
Key to multiblade design is not to just add a blade; this will add to the parasite drag and reduce induced efficiency.
You need to maintain or slightly increase solidity (total blade area) and retwist airfoils to the optimum spanwise load distribution (which is not necessarily elliptical and is different as you add blade count).
We also generate all new airfoils for the new design point.

[n816kc]

And, it may be very cost effective. I’ve got a metal Sensi on my -6, thinking about the adjustable. Lots of Catto salesmen out there, for good reason. Price wise they’re pretty close, unless...

To put a Catto on my plane I need a new Sabre extension, crush plate and hardware, an extra $1000-1200. The adjustable Sensi bolts right up. The turnaround on a pitch adjustment is an afternoon instead of weeks.

Good reports from the RVs running them so far.

[N941WR]

A neighbor bought a new Cub-a-Like that was powered by an O-200D spinning the Sensenich GAP.

The prop was so stiff, his mags wouldn't last 30 hours.

The solution was to go with a Catto, which he has been VERY happy with.

I realize there is a BIG difference in engines and props here, but if that small prop is stiff enough to cause those types of issues on the little engine, I wonder what the long term impact to the bigger Lycoming would be.

[vfrazier]

I just installed one and, so far, am quite pleased with the improved performance. And it looks great too.

http://www.vansairforce.com/communit...d.php?t=178056