Steve Pierce
BENEFACTOR
Sensenich Ground Adjustable Prop
- Thread starter FullThrottle
- Start date
Supercubrancher
PATRON
NE
So what is the difference between the certified and experimental prop, besides the sticker that says FAA approved?
Steve Pierce
BENEFACTOR
Graham, TX
Paperwork
supercrow
FRIEND
Smith Pond near Millinocket, Me
Yup. That would be the difference. And the props already in the field will always be exp. and the approved will be twice as much money. One more of the reasons I fly an exp.
Steve, do you know if approval is being pursued for installation on a 150 hp PA-12 for this ground adjustable prop or only PA-18 at this time? Thanks
Steve Pierce
BENEFACTOR
Graham, TX
PA18 with 150 and 160 hp O-320. The prop will then be Type Certified which will make it easier for others to get STCs for other aircraft. There have been DER approvals on O-360 powered Cessnas based on the data from the PA18 180 hp STC.
I sure wouldn’t want to be the DER that approved that. The PA-18 STC is an airframe STC based on the “new” Part 23. The approval is based on the airplane being a “Level 1” airplane, defined as having 0 to 1 passenger seats. The engineering rigor for a Level 1 is much less than for a higher level. FAA changed the certification rules based on “risk to the public”, so less seats is less risk. That’s part of the reason Sensenich changed gears and is now working on getting a TC for the prop. That opens up the availability to aircraft with more than 2 seats.
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akavidflyer
FRIEND
Soldotna AK
Sensinich changed up because anything government related is a pain in the ass and next to impossible to deal with as they keep moving the target. Kind of like the full lotus float testing. Drops at gross, double gross then triple gross didn't result in airframe failure as the floats absorbed the impact. Without a "known failure mechanism" they refused to certify the installation. Makes a lot of sense to essentially remove the safety of airbags from being used in the certified world, yet there are so many examples flying safely in the "experimental" world.
Steve Pierce
BENEFACTOR
Graham, TX
The flight test engineer that was here was on the committee that wrote that. He interpreted it differently than it was sold to us. He is right at home with the FAA.
BritishCubBloke
SPONSOR
Bellingen, NSW, Australia
Do we have any idea when the 320 STC will be completed?
Steve Pierce
BENEFACTOR
Graham, TX
No idea, waiting on the FAA. Will updater this thread as things move along.
BritishCubBloke
SPONSOR
Bellingen, NSW, Australia
Thanks. Presumably Catto has given up on the STC process now?
Last I heard.
Flight testing not quite complete due to wreck. ( When will this start again?)
Things should happen fast after testing (fed’s slow down complete.)
Props are being built, and should be sent out fast after the rubber stamp.
Utah-Jay
MEMBER
Heber City, UT
Don’t bet on that, mine was supposed to ship Feb 28th, they are a least a month behind as mine might ship in the next couple of weeks. I think the experimental market is keeping them busy at the moment
edited to add: it’s shipping today
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Steve Pierce
BENEFACTOR
Graham, TX
Cooling and dive tests complete. Have to do performance test now, take-off, climb and landing. After that data is compiled they put the noise test criteria together but the FAA noise test engineer has ass chap with the noise test DER. The DER has an amazing reputation around here and works with McCauley and Hartzell but someone has a burr up their butt. Sensenich does not have enough production to keep up with demand. Can't hire enough people. I am going to Sensenich the week after next to tour the plant. Will report back.
and therein lies the the problem. Being married to someone that has worked for both state and federal government for nearly 30 yrs, I can tell you that Government competence is not allowed, seriously discouraged, and will always be punished.
BC12D-4-85
SPONSOR
Fairbanks, AK.
Local experimental PA-18-160 will get back to back Borer/Sensenich adjustable starting this weekend. Prop arrived this week. Will report tho not my plane. It's on Aero skis so the pull in deep snow will be interesting.
Edit: Will also try to get him to do climb rate and cruise speed vs fuel flow and airspeed at his preferred rpm.
Gary
Edit: Will also try to get him to do climb rate and cruise speed vs fuel flow and airspeed at his preferred rpm.
Gary
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BC12D-4-85
SPONSOR
Fairbanks, AK.
Here's the initial test results from 3/26/22 in Fairbanks for the 82" Sensenich. It was +40F at ~450 msl with wind less than 5 mph. Plane is EXP PA-18-160 w/Dakota Cub wings, long gear, and Thrustline engine mount. Owner is pleased. So far better performance compared with a Catto 82/40 and Borer 82/42.
Capt. Eddie at the stick
Capt. Eddie at the stick
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BC12D-4-85
SPONSOR
Fairbanks, AK.
^^^^There will be more testing in the coming weeks as the owner explores the prop's performance envelope. Things like cruise performance vs fuel flow and rpm. One thing I noted while he was testing was it cranked and started quickly...same for shutdown. It spun up fast if power was needed in flight. Weight of about 19# compared with metal Borer at 33# we had just removed.
Edit: One thing I noted as an observer was the sound signature on takeoff. At the "0" pin full flat pitch setting it sounded smooth during takeoff and pulled good like the Borer 82/42. At "2 and 4" pins it initially sounded like ducks farting in shallow water...typical for some blade cavitation common to getting on step with a floatplane until it starts really pulling.
Blade track was checked to be within 1/8" and it reportedly ran very smooth with no rpm-related rough spots. It truly took 5 minutes to change the prop pitch with the supplied variable diameter setting pins. The supplied Nord-Lock washers under the bolt heads make it easy and secure. We checked the torque of the bolts after an initial run and after every pitch change. They held true after a few flights.
The only concern now may be to add a cover plate over the adjusting pin holes to exclude water and debris. There's threaded holes next to them to attach a cover (or just duct tape :lol
I was impressed with the quality of the setup and would own one. They make an EXP for my Taylorcraft.....hmmmm.
Gary
Edit: One thing I noted as an observer was the sound signature on takeoff. At the "0" pin full flat pitch setting it sounded smooth during takeoff and pulled good like the Borer 82/42. At "2 and 4" pins it initially sounded like ducks farting in shallow water...typical for some blade cavitation common to getting on step with a floatplane until it starts really pulling.
Blade track was checked to be within 1/8" and it reportedly ran very smooth with no rpm-related rough spots. It truly took 5 minutes to change the prop pitch with the supplied variable diameter setting pins. The supplied Nord-Lock washers under the bolt heads make it easy and secure. We checked the torque of the bolts after an initial run and after every pitch change. They held true after a few flights.
The only concern now may be to add a cover plate over the adjusting pin holes to exclude water and debris. There's threaded holes next to them to attach a cover (or just duct tape :lol
I was impressed with the quality of the setup and would own one. They make an EXP for my Taylorcraft.....hmmmm. Gary
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BC12D-4-85
SPONSOR
Fairbanks, AK.
Here's a final test sheet for Post #169 above. It includes a test flight with adjustment pin #5 of the six available (0 through 5; 0 is the flattest pitch). Capt. Eddie said #5 still performed well on takeoff but was best for cruising. Next testing will be with a loaded airplane. Current fights were pilot and half or less fuel in the Dakota tanks.
Gary
Gary
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This was my Cessna that was able to get the field approval. The local FSDO was great to work with and forwarded it to the Chicago ACO engineers. So no DER was involved, it was all FAA. I just completed the O-360 engine swap, so still flying with the prop in the middle pitch setting but the performance is incredible.
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DJ
MEMBER
Bolivia
jrussl
BENEFACTOR
Madison, WI
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