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Sensenich Ground Adjustable Prop

They just received the Type Certificate on the prop. This is a big deal because now it is easier for others to obtain other STC's on different aircraft. As far as the STC on the 150/160 hp Super Cub is concerned it is in a quagmire between FAA noise test engineers and their pother engineers as to the testing procedures. We are finishing up repairs on the aircraft the FAA ran off the runway this week. I can say this has been a frustrating experience on so many levels. The good thing is I have learned a ton and the Sensenich engineers are great to work with and have taught me a lot about props. Just installed an STC'd 180 hp prop on an Amphib Super Cub on Tuesday, saved 24.5 lbs, leading edge won't erode away like aluminum and the pilot tells me it is getting off the water quicker as well.
 
Looking forward to hearing more - these McCatto lengths/pitches are all over the place so I think it would be hard to get an apples to apples test short of measuring thrust output on the same powerplant for all the combinations.
 
Seat of the pants, after going back and forth from an 84” Catto to the GA, says the GA pulls as hard out of the hole but is considerably faster even on the finest pitch. Also glass smooth if care is taken keeping the pitch and clamshell halves lined up.

One area the Catto may win on is the strength of their nickel leading edge. The stainless leading edge on my GA appears softer or maybe it’s just not as lucky as my Cattos;-)

Maybe Ford will chime in. He’s had a chance to play swap-a-prop on both wheels and floats.
 
Seat of the pants, after going back and forth from an 84” Catto to the GA, says the GA pulls as hard out of the hole but is considerably faster even on the finest pitch. Also glass smooth if care is taken keeping the pitch and clamshell halves lined up.

One area the Catto may win on is the strength of their nickel leading edge. The stainless leading edge on my GA appears softer or maybe it’s just not as lucky as my Cattos;-)

Maybe Ford will chime in. He’s had a chance to play swap-a-prop on both wheels and floats.

You almost didn’t get it back. It’s really impressive that everything is the same except the pitch, how much cruise you will get.
On the climb pitch (0) I got 2560 static, 2550 indicates 85mph

On the cruise pitch (5) 2350 static 105mph cruise. There’s a noticeable difference in takeoff performance.


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A little more info on setting prop pitch and torqueing.
Steve,

The most common source of vibration after repitching a propeller is incorrect blade angle.The clamp gap on each side of the blades should be equal prior to setting pitch. A visual check is generally sufficient, but feeler gauges or similar tools may be used if desired.
sensenich1.png

Hand-tighten the clamp and through mount bolts until turning the blades requires some effort to counteract the friction. The blades should be snug but movable with moderate effort. Ensure the clamp gap is kept equal during this process.


After setting the pitch for a blade, tighten the clamp bolts(roughly 1/4 to 1/2 turn) around that blade to ensure it does not change pitch while adjusting the remaining blade. Ensure the clamp gap is kept equal during this process.

sensenich2.png

Torque the 4 mount bolts incrementally to full torque. Applying full torque to 1 bolt prior to tensioning others can rock the mount cover and change pitch of the blades(one blade goes up and one blade goes down).


Torque the 4 clamp bolts incrementally to full torque. Then re-check all bolts. It is common for a clamp bolt to turn another 1/8-1/4 turn after torquing the clamp bolts.


Recheck that clamp gap is approximately equal. You can also use the next pin size down to check that neither blade de-pitched during installation.



 

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Who does FAA authorize to adjust the prop pitch on an aircraft with a standard airworthiness certificate? What, if any, log entries are required?

Just curious because the closest I can legally get to the propeller on my PA-28 is to check/replace the safety wire. I'm not considered competent to remove/replace/torque the bolts that secure its fixed pitch prop.
 
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A little more info on setting prop pitch and torqueing.
Steve,

The most common source of vibration after repitching a propeller is incorrect blade angle.The clamp gap on each side of the blades should be equal prior to setting pitch. A visual check is generally sufficient, but feeler gauges or similar tools may be used if desired.
View attachment 61386
Hand-tighten the clamp and through mount bolts until turning the blades requires some effort to counteract the friction. The blades should be snug but movable with moderate effort. Ensure the clamp gap is kept equal during this process.


After setting the pitch for a blade, tighten the clamp bolts(roughly 1/4 to 1/2 turn) around that blade to ensure it does not change pitch while adjusting the remaining blade. Ensure the clamp gap is kept equal during this process.

View attachment 61387
Torque the 4 mount bolts incrementally to full torque. Applying full torque to 1 bolt prior to tensioning others can rock the mount cover and change pitch of the blades(one blade goes up and one blade goes down).


Torque the 4 clamp bolts incrementally to full torque. Then re-check all bolts. It is common for a clamp bolt to turn another 1/8-1/4 turn after torquing the clamp bolts.


Recheck that clamp gap is approximately equal. You can also use the next pin size down to check that neither blade de-pitched during installation.



thanks Steve will try this
 
Who does FAA authorize to adjust the prop pitch on an aircraft with a standard airworthiness certificate? What, if any, log entries are required?

Just curious because the closest I can legally get to the propeller on my PA-28 is to check/replace the safety wire. I'm not considered competent to remove/replace/torque the bolts that secure its fixed pitch prop.

Off the top of my head, unless the ICA that comes with the STC says otherwise - Given that adjusting ground adjustable props is not listed in 14 CFR 43 Appendix A under Preventive Maintenace or as a Major Repair, that would put it as a Minor Repair by the definition in 14 CFR 1.1. No matter who does it, 14 CFR 43.9 would require a maintenance record entry.
 
Steve - any more info behind the curtain? I tore my leading edge on my Borer on my last flight. I'm not sure it's dressable. I might have to hold tight and wait for the STC to pop.
 
I’ve had a few people try and order some for exp, sensnich must be really busy already. They never got back to them.


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They are very busy. Chief engineer and president are down here with the flight testing. Got the take-off performance testing done and Vx and Vy climb testing done at high and low pitch on the ground adjustable and hope to do the base line testing on the Sensenich 74DM stock prop in the morning. Got the base line and high pitch setting landing test done this morning before the wind got up. Have a 7 mph limit on wind flying a 3 degree PAPI approach. Kinda weird flying a stock 150 hp Super Cub with 600x6 tires at gross weight with a 250 lb FAA test pilot in the back seat. The Baby Bushwheel was shimmying pretty bad so after the take off performance tests I convinced them to let me put a Scott 3200 on it and that was a lot easier to land. Would have gotten the Vx and Vy climbs done today but blew out a starter button at Breckenridge and had to improvise to get it home and a new switch installed. By the time I did that we had clouds and couldn't climb to 8k feet. I still really like the prop, still out performs any of the certified alternatives and the benefit of 15 or so pounds off the nose and a stainless steel leading edge. I was able to get a field approval on my airplane and have been running it for a few weeks. Will update more as I get a break.
This is the test airplane with the baseline Sensenich 74DM that most PA18-150s came from the factory with. Unlike last time when they made us test against a 1A175 McCauley (Borer) prop.
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Mine with the field approved Sensenich 2GoM6/C82 prop.
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Starter button!? The cub gods are trying to send you a message. You don’t need the button or the starter attached. What you need is a good shoulder surgeon;-)
 
Those are some little tiny tires!

sj

They make it challenging with a cross wind, shimmying Baby Bushwheel tailwheel 250 lb passenger at gross weight. No shimmy today with the 3200 and the landings were a piece of cake but you better not drop it in cause it'll jar your teeth. Add in the comments from the back seat FAA test pilot when the landing isn't so smooth. :lol: :oops:
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Starter button!? The cub gods are trying to send you a message. You don’t need the button or the starter attached. What you need is a good shoulder surgeon;-)
Keeping my starter and foregoing the shoulder surgery at this point. I'll leave that hand propping to you young bucks. ;)
 
LOL, he has been good, I have gotten some interesting sounds when I pull the stick all the way back in the flare. :Ghuh:
 
I’ve had a few people try and order some for exp, sensnich must be really busy already. They never got back to them.


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I have had my 82” GA prop for several months, but then I figured once the certification happened (long over due obviously) they would be hard to get. Hence I ordered mine a LONG time ago.

I like having things in hand even well before I need them.
 
Steve why is your gear splayed soooo far OUT??? Can't imagine how far that must tilt those tires when your at GW??? Is that being caused by the shocks not having correct tensions; to hold the weight of the plane?? Not being critical here, just an honest question?
The new Cub looks great.
E
 
Earle, it will be interesting to get Steve's take on this but I think you will find it works best for the type of off airport landings he is making down his way. The developers of the shock systems we are seeing the last few years refer to the travel limits of there systems as compression and sag. Most recommend exactly what you are referring to as preferable because it increases the overall distance the unit is allowed to travel which simply means more usable shock absorbtion in particularly rough ground. And I suspect the slight splay out might also increase stability at touch ground on very rough areas? Interested to hear the take others have on this. The monster shock system I use talks about setting them up to allow that extra movement. I prefer a more level stance for mine, but i am not generally using like Steve does down along the river.
 
Steve why is your gear splayed soooo far OUT??? Can't imagine how far that must tilt those tires when your at GW??? Is that being caused by the shocks not having correct tensions; to hold the weight of the plane?? Not being critical here, just an honest question?
The new Cub looks great.
E

Spinning it around and it wasn't bottomed out.
 
Steve why is your gear splayed soooo far OUT??? Can't imagine how far that must tilt those tires when your at GW??? Is that being caused by the shocks not having correct tensions; to hold the weight of the plane?? Not being critical here, just an honest question?
The new Cub looks great.
E

This is just pushing it straight back, Burl's AOSS.
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