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Wirlwind STOL ground adjustable propeller

For lack of any other input, you can do it the old fashioned way: take a wild assed guess, eyeballing another prop to get you in the ballpark, and then do a static run up. No real need to mess with a torque wrench, just a quick and dirty test, on the ground. It took me 4 tries before I nailed the static I wanted, and just an hour or so. Also not necessary to get all anal about the blades being EXACTLY the same pitch, save that and the torque wrench for the final setup. Same principle as the way we Rotax guys do it, crude but it works.
 
I'm in the process of getting a new to me used WW 75" 3 blader dialed in for my Rotax Rans S-7S combo. A smaller dia then my usual 78" Prince 2 blade, for my winter flying. A few times I've moved a little snow with the Prince so a bit less dia will be helpful.

It didn't occur to me though, until I was perched on the edge of my ski ramp with the tail release still hooked and the engine idling, that I had better make real sure I didn't have a brain fart and set it up backasswards, so I shut down and held the Prince up next to it and determined FOR SURE that everything looked about right! As it was the snow was sticky, and I used every bit of my 400' of runway before finally getting unstuck. Testing a new prop on a sloped short strip on skis is not ideal but so far so good. Subsequent landings elsewhere showed the poor takeoff performance was indeed due to unusually sticky snow. But I still was able to determine that 1 more degree of pitch may be helpful, and in an easy hour, counting taking the cowling off and putting the tools away, made the adjustment. WW vaguely says "level" the prop while you adjust pitch, my scimitar blades made that problematic so I just eyeballed level more or less, and found that my chin was the same height as the blade tip. So I used that to determine the same height/arc of rotation of the blades as I adjusted each, otherwise I would have used a stick, anything to serve as a jig to keep it all consistent. FWIW, I'm at 16 degrees, different planes and engines but I guess similar aero demands of the propellers.
 
I have a WW ground adjustable, 82" for o360, that is for sale, great prop, just went in a different direction. PM me if you are interested.
 
I have a WW ground adjustable, 82" for o360, that is for sale, great prop, just went in a different direction. PM me if you are interested.
Thanks but just bought one and had installed yesterday. Gained 9mph after three adjustments. And sooooo smooth!
 
08D310FC-0B99-4E32-8395-C1C14D5AE0A4.jpegI posted this in another thread but thought would be helpful here. An easy way to set the blade angle by making a jig to hold a smart level. The blade profile was set with the provided Whirlwind protractor to 0 degrees and now the level measures the angle change from 0 degree reference.
 

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Or get the sensenich and toss out the angle finders, protractors and jigs. Change pitch in a couple minutes and be on your way.
 
I have purchased a Sensenich ground adjustable prop from a dealer in Soldotna late last year with the understanding from the dealer that the STC would be issued to the purchased prop for my Super Cub once the STC was finalized. The most recent communication I have heard is that Sensenich is not going to issue STC to any props sold before the certification date.
 
I'm checking in with Sensenich asap to get some props brought in to sell and I'm curious how they're handling that. It's normally pretty rare to be able to pre-sell an item and then have a later STC be applicable to it. I'll check with them and see if that's possible.
 
I'll be interested to see how that 3-blade works with the 390. What's it weigh?

22 pounds.
Prop set at 14.7 degrees got 2350 static for its first full run up today.
Ready for inspection!
 
So 25# lighter than my constant speed. Nice. So is 2350 your target or is that set course for break-in?

One of my prop specification head-scratcher questions will be answered soon. If your fixed pitch prop static is 2350 and mine is 2700 which has more static thrust and how does that translate to acceleration to takeoff? Then there's cruise speed, fuel burn, etc. It should be interesting. When's the first flight? Enjoy!!!
 
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I have purchased a Sensenich ground adjustable prop from a dealer in Soldotna late last year with the understanding from the dealer that the STC would be issued to the purchased prop for my Super Cub once the STC was finalized. The most recent communication I have heard is that Sensenich is not going to issue STC to any props sold before the certification date.

As did I. I was also told by Sensenich that they would be doing the testing on my plane when they were here doing the testing on the 18 and that ended up not happening. The initial discussion was that they would "take care of" the guys that had bought them prior to the STC as nothing was is is changing in the manufacturing process or QC of the components. That is yet to be seen, but regardless, I still love the prop and the ease of changing pitch and the performance increase I got over the Borer.
 
So 25# lighter than my constant speed. Nice. So is 2350 your target or is that set course for break-in?

One of my prop specification head-scratcher questions will be answered soon. If your fixed pitch prop static is 2350 and mine is 2700 which has more static thrust and how does that translate to acceleration to takeoff? Then there's cruise speed, fuel burn, etc. It should be interesting. When's the first flight? Enjoy!!!


The prop is set course for break-in and awaiting inspection for special airworthy certificate. Not going to taxi test as I think it would fly before going 50 yards!
 
I promise it will. My first flight was at Birchwood, so lots of space to get it off the ground and test controls with runway ahead of me. Short takeoff wasn't the priority but the plane leaped into the air. First flights are a mix of excitement and uncertainty. So much fun!
 
Quick update: Spoke with Sensenich today, he said they have the STC for the O-360 GA prop now and are getting that prop added to the certified production list. The O-320 GA prop is estimated to have an STC in June and they will have approved production at that time.

Props sold before STC and approved production WILL NOT be eligible for an STC at a later date. The prop has to be build under the STC/PMA approved production to be able to have an STC applied.
 
Props sold before STC and approved production WILL NOT be eligible for an STC at a later date. The prop has to be build under the STC/PMA approved production to be able to have an STC applied.
This is standard procedure. Any promises to buy now certify later don't happen. Not just Sensenich, but with anyone. The FAA's blessings don't start until the ink on the certification signature is dry.
 
Quick update: Spoke with Sensenich today, he said they have the STC for the O-360 GA prop now and are getting that prop added to the certified production list. The O-320 GA prop is estimated to have an STC in June and they will have approved production at that time.

Props sold before STC and approved production WILL NOT be eligible for an STC at a later date. The prop has to be build under the STC/PMA approved production to be able to have an STC applied.

Did they say anything about O-235 STC?


Sent from my iPad using Tapatalk
 
Nothing about the O-235. They are STCing the O-320 and O-360 models for PA-18-150's in 78", 80", and 82" sizes.
 
85/90/235/290 are all a year away from any sort of stc.


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