Sensenich Ground Adjustable Prop
FullThrottle akavidflyer FRIEND Soldotna AK western NY C CWilson Registered User D dgapilot FRIEND Steve Pierce BENEFACTOR Graham RaisedByWolves FRIEND Tx S sixmile MEMBER Nondalton Farmboy MEMBER Middlebury T TomT FRIEND
I have copies of field approvals on 150 Pacer and 180 hp Scout. Steve@pierceaero.com
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SuperCub.Org
Hi Mojo,

My experience with the certified prop was they give you 2 pins for a total of 4 settings …settings 2-3 and 4-5. From what I understand the STC does not include the flatter pitch 0-1 pin settings due to it not passing the noise requirements during testing. Hope that is helpful.

Justin

While this might work for 180HP, it won't work for crap on the 150/160 HP engine. Local guy got his for a 150HP cub and the way the prop hub is drilled and the pins he got, the lowest pitch he can get is 39. That is WAY too much for that engine. 35 works great for take off, 36 is a good compromise between take off and cruise. Why they would send out a prop for a 150 HP with 39 being the lowest pitch he can get is mind boggling to those of us who have done EXTENSIVE testing on MANY airframes including the original 180HP certification testing.

If they want to get a bad rap for performance out of this prop and get people pissed off for paying lots of money for a prop that's not going to give much better performance than a borer, this is the way to do it. The only thing this prop has going for it as they are sending them out the door now is being lighter weight.

This being said, if people want to get some real performance out of the prop, take the pins down to a machine shop and have them turned down so you can get the prop into the 35"-36" range for the 150 and 160 HP engines.

Akavid, I assume you determined the pitch using a pitch gauge and adjusted to get the pitch and performance needed.

(Assuming the smallest pin didn’t work for you, there’s no good reason you can’t mill one down smaller for your mission)

For others that don’t know, and unless they have changed, the pitch numbers that Sensenich uses does not align with metal prop pitch numbers. This was something there engineer told me about when we were testing the small continental (85-100) and O-290 props.

Sent from my iPhone using SuperCub.Org

I did state above that the pins can be machined down, I was the first to do it years ago to really fine tune the prop for my use. We have years worth of testing and data on the prop on many airframes and engine combinations, long before Steve got into the testing etc. They have changed the location of the pin in the hub several times over the years and now the pitch pin numbers no longer correspond to the actual pitches we used, so the pitch pin diameters I am using will mean nothing to anyone who has one of the newer props.

As far as the " of pitch, its "close enough" and the installation instructions show a chart with pin numbers and "pitch" numbers (see table 2 Pitch setting gage and Corresponding Blade Angles) The 0 pin would be 11 degrees or 38" pitch. 38 is the COARSEST I bothered trying on a 160 as take off performance and climb was down remarkably from 36. 34 was great for take off but cruise completely fell on its face. 35.5 was the magic number for my plane that gave me good TO and still keeps cruise around 105.

I would venture that the average guy going for 150 dollar hamburgers wouldn't know the difference as most guys just say it "feels better or it feels worse" Feelings are not very accurate and static pull tests don't tell all. Actually recording data, and having hard numbers to look at does tell the story and takes feelings out of the equation.

I can understand why, for the certified prop, they had to limit the pitch for the sound testing, but it really makes those of us who raved about the performance of the prop and have hard testing data look stupid when a guy gets his new prop that should kick the crap out of his borer, and now he finds that it only performs MARGINALLY better and he is pissed off at the money he just spend on this prop. I would be livid to read all the raves then find out that I spent a lot of cash for this prop that, as sent from the factory, doesn't preform as well as expected. Same goes for having to deal with a dealer that came late to the party and can't tell the pissed off customer why his engine wont pull the RPM that others do or has the performance that others are getting.

I have heard from guys that thought they must have a sick engine because it won't pull even close to the numbers that mine and many others we tested will pull so they start down that rabbit hole of chasing sick engine issues, only to find out that the pin we used now corresponds to 4" more pitch and that they can't get even close to our pitch without having the pins machines or going old school and using a protractor etc. This completely wipes out the advantage and selling point of this prop.

I am suppose to be getting copies of a signed 337 for a PA12 as well but have not received it yet. This prop has a type certificate and is approved on the Lycoming O-320 and O-360 and has vibe test per Note 9 which makes it doable via field approval. The small Continental prop has not as of yet and I have no knowledge of any field approvals for those propellers. I will share this paperwork and help where I can. All I ask is consider buying the propeller through me. I have spent a considerable amount of time on this project and selling props is how I recoup that time.

Hey, Steve. Regarding the prop for smaller engines, I can understand why Sensenich isn't in a rush for certification on standard category airplanes. I'm guessing the market for them is much smaller than thst fot the larger props. In a seminar at Sentimental Journey about a decade ago, Don Rowell mentioned that they were considering standard catagory certification for the small prop, but thats as far as it got.

If you happen to be in contact with the folks at Sensenich you might mention this. I have access to a a PA-11 90 and two PA-12s with O-235s. All of them are absolutely stock with no modifications. I have an A&P certificate [not with IA, unfortunately]. I am also retired and have the time to devote to an extended project. If Sensenich ever considers standard certification, I would like to help.

While this might work for 180HP, it won't work for crap on the 150/160 HP engine. Local guy got his for a 150HP cub and the way the prop hub is drilled and the pins he got, the lowest pitch he can get is 39. That is WAY too much for that engine. 35 works great for take off, 36 is a good compromise between take off and cruise. Why they would send out a prop for a 150 HP with 39 being the lowest pitch he can get is mind boggling to those of us who have done EXTENSIVE testing on MANY airframes including the original 180HP certification

If they want to get a bad rap for performance out of this prop and get people pissed off for paying lots of money for a prop that's not going to give much better performance than a borer, this is the way to do it. The only thing this prop has going for it as they are sending them out the door now is being lighter weight.

This being said, if people want to get some real performance out of the prop, take the pins down to a machine shop and have them turned down so you can get the prop into the 35"-36" range for the 150 and 160 HP engines.

Pool

I had an issue with not getting enough RPM out of my O-320 when I first installed the propeller. I called Sensenich and had a visit about the issue. It turned out the blades were set up for an O-360. I sent the blades back to get the pitch pins positioned correctly for an O-320. I had the blades back in a week. Sensenich’s customer service was excellent! Figure out your problem before you start machining.

The STC'd prop comes with pitch pins 2-5 (41-46 pitch). Yes, the pitch limits were made due to the results to the noise tests. If you want a 0-1 pitch pin I am sure you can get one. What can get approved and what people do in the real world can be two different things. I run pitch pin 3 on my 160 and it will overspeed if you stop pulling the stick without pulling the the throttle. It is nice that you can try different settings and see what works best for you. Still hands down better than my Borer ever was.

What diameter are you running? If you are pulling the "new" 3 with 160 its gotta be a shorter prop, or you have one of the props that has the base pins in the original location. I have to pull power back as soon as I start pushing the nose over as well. Take off I turn 2650ish and pulled back in cruise I run 2500 to 2550 and 20.5 to 21" MP at 1500 ASL. At 11K pulls 17.7" @ 2550.

The base pins have been drilled a few different ways since the beginning so the actual pitch (or semblance there of) is the only constant we can compare. your #3 pin could be anywhere from (36 original) to (43 today) and I know for a fact that a 160 is not gonna pull 43. We have WAY too much empirical data on way too many different planes and engine combinations.

What diameter are you running? If you are pulling the "new" 3 with 160 its gotta be a shorter prop, or you have one of the props that has the base pins in the original location. I have to pull power back as soon as I start pushing the nose over as well. Take off I turn 2650ish and pulled back in cruise I run 2500 to 2550 and 20.5 to 21" MP at 1500 ASL. At 11K pulls 17.7" @ 2550.

The base pins have been drilled a few different ways since the beginning so the actual pitch (or semblance there of) is the only constant we can compare. your #3 pin could be anywhere from (36 original) to (43 today) and I know for a fact that a 160 is not gonna pull 43. We have WAY too much empirical data on way too many different planes and engine combinations.

I have no idea. All I know is that I like pin 3, it gets off better than my Borer and is faster. I will not be reinstalling my Borer prop. I have sold a lot of props and have not had a complaint and I know several were for 150 hp. I guess we will see.