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Re: Sensenich Flight Test Report

PostPosted: Fri Feb 13, 2015 5:04 pm
by Av8r3400
I've been told not to trust the adjusting pin solely for pitch setting. You need to confirm with a protractor that all blades match, because they can and will vary.

Has the hub system been improved or does this still apply?

Re: Sensenich Flight Test Report

PostPosted: Fri Feb 13, 2015 6:12 pm
by Jack L
Av8r3400,

If you are referring to the Sensenich propeller we address the alignment pin and digital protractor in this post. The problem is not necessarily with the hub but the pitch pin on the blade. In my case I tried to use the pitch setting gauge several times and when I verify the blade angle with a digital protractor the blades are out. Since I was able to set the blades with the protractor this indicates that the problem is not with the hub. When I told Sensenich about the problem they asked me to return my propeller to them so that they could correct the problem and I chose not to return it until the thaw.

This picture shows that to set the pitch angle the blade is rotated until the pitch pin comes in contact with the pitch setting gauge, it is that pitch pin that may be out of alignment.

Pitch Pin.png


Jack

Re: Sensenich Flight Test Report

PostPosted: Fri Feb 13, 2015 11:19 pm
by av8rps
Mark,

That IVO medium does work well on the Highlander. I actually recommended that prop to Howard. He could cruise at 100 mph on floats with it, and still had a really good climb while still providing a reasonably short water takeoff.

But since all of us are always trying to find the "perfect" prop for our planes, sharing what we experience with other brands is something that can really help us find the best prop for our particular needs. And even though we are flying the same basic airplane, our needs can vary a lot. So the more we can learn from one another about the various props, the better off we all are.

Paul

Re: Sensenich Flight Test Report

PostPosted: Sun Feb 15, 2015 9:34 am
by av8rps
Jack L wrote:I finally got around to testing my Sensenich propeller after setting the pitch with a digital protractor. The blades were set to 12.5 degrees which is producing a WOT just over 5500 RPM in cold air, It should go higher when the OAT increases. Two climb tests were performed starting at 1900 ft and in one minute the aircraft climbed to 3200 feet at both 65 and 60 MPH which equals 1300 FPM. My all up weight was somewhere around 1100 lbs during these tests, I am pretty happy with the climb rate. As for speeds all I ever hoped for was 100 MPH at 5100 RPM and I am pretty close to that so I cannot see pitching the propeller coarser to get more speed ....snip

Jack


Jack,

I've always found with 912's that to get optimum overall speed and climb that you need to get close to 5800 rpm when straight and level and wide open throttle. (I proved that to myself again and again by adjusting my IVO in flight adjustable prop - as it is so easy to adjust pitch to experiment)

Based on that experience I believe you can get a bit better performance out of your sensenich by setting your prop slightly flatter. But that's just my two cents.

I really enjoy your videos. You have a very nice Highlander.

Paul

Re: Sensenich Flight Test Report

PostPosted: Sun Feb 15, 2015 10:13 am
by MarkZ
Thanks!

Re: Sensenich Flight Test Report

PostPosted: Sun Feb 15, 2015 1:18 pm
by Jack L
Paul,

You are right, I was told by a Rotax factory technician that if you are not developing 5800 RPM that you are robbing the aircraft from the available HP that the engine can produce. I also understand that temperature has a significant impact on RPM and to get to 5800 in the cold weather I may have to fine the pitch out a little and once it gets warmer out there I will likely have to pitch coarse again. This is where an in flight adjustable propeller like the IVO you talk about would be so nice because regardless of atmospheric conditions you can always get the most out of your engine.

Thanks for the feedback, I appreciate your comments.

I will be asking for your advice on rigging my Zenair floats on another post, I could PM you but I know there are others that appreciate learning from the knowledge you have on this subject as well.

Jack

Re: Sensenich Flight Test Report

PostPosted: Sun Feb 15, 2015 7:14 pm
by SheepdogRD
Looks like the Ivoprop ultralight in-flight adjustable - specifically for Rotax engines to 100 hp - is currently $1400. Mounting weight with all controls and the spinner is 10 pounds.

Can that prop really provide the best of both worlds - climb and cruise?

They weigh a little more than a ground adjustable, and they can't be operated by a Sport Pilot. Any other reasons I wouldn't want one?

Re: Sensenich Flight Test Report

PostPosted: Sun Feb 15, 2015 8:24 pm
by Jack L
It sounds really good at $1400 Sheepdog, let us know how it works out.

Jack

Re: Sensenich Flight Test Report

PostPosted: Sun Feb 15, 2015 10:59 pm
by SheepdogRD
Jack L wrote:It sounds really good at $1400 Sheepdog, let us know how it works out.

:D I'm not ready to order a prop yet, Jack, but it's on my list. I'm down to a half dozen choices on the short list. I figure the best information will come from Highlander and SuperSTOL pilots, and second-best will be pilots of other Dean Wilson-inspired designs.

Re: Sensenich Flight Test Report

PostPosted: Mon Feb 16, 2015 2:33 pm
by av8rps
Richard,

If I recall correctly, Steve Henry's "Dead Stick Takeoff" was made with a Highlander with a standard 95 hp Rotax 912ULS and a 3 blade IVO ultralight in-flight-adjustable prop. So if I'm correct, that should be the best testamonial for the IVO IFA.

Plus, if you hang around the Kitfox group you will learn that if you want to fly with the gang out west you are going to need an IVO IFA, or you won't be able to keep up with them. And that doesn't mean just in cruise speed, but also in the ability to climb over the mountains.

I fly an IVO IFA on my Kitfox 4 amphib floatplane with an 80 hp 912ul. Ironically, I didn't install an IFA for the speed, I was more interested in takeoff performance because I only had 80 hp. Plowing a floatplane deep through the water onto the step is where you need the most power, and that IVO allows me to pitch to 5800 rpm on initial throttle application, which allows me to use all 80 ponies. That ability basically reduces my takeoff time to half of what it would be with a ground adjustable prop, if it were set even at a higher static setting (E.g.; 5450 Static - or in other words, set for a better climb rate).

So unless I were to set a ground adjustable prop for 5800 rpm static, I would need a larger engine to get similar takeoff performance to what I have now. And even though I was prepared to install a 95 hp 912 ULS if I had to (I even have a spare engine just waiting to be bolted in), with the IVO IFA I really don't see a need to change it. In fact, I am blown away by how my little 8o hp Kitfox amphib performs; On floats it will go 125 mph wide open, cruise at 100 mph at 3.1 gallons an hour, and climb at a thousand fpm with me and a bit of gear and 4 hours of fuel. And if I want to show off, if I keep less than 10 gallons of fuel in it and have near perfect water conditions, I can get it off the water in 6 seconds! (fwiw - that would be excellent performance from a 160 hp lightly loaded straight float Super Cub in similar conditions. It's not uncommon to see 25 - 35 second takeoff times from larger amphibs like Cessna's, Beavers, etc)

I have tested my IVO prop by adjusting it for various static rpms simulating a ground adjustable and have learned that the IFA option gives me about 6 mph, and probably 200 fpm in climb. Ironically, based on what others have experienced, that is about the same performance I would gain if I went to a 95 hp 912 with a ground adjust prop. But of course if you had an IVO IFA AND a 95 hp 912, you'd have incredible performance :shock:

So if you can live without LSA status, I'd highly recommend the IVO IFA prop. BUT, there will be a few downsides. One is increased maintenance as it is more complex having an electric motor and gears that a regular prop doesn't have. Another is the IVO stainless tape (you will need for flying water) has a tendency to need replacement at least every season. The medium blade IVO is better than the UL blade for that, but it will still need it.

Paul

SheepdogRD wrote:Looks like the Ivoprop ultralight in-flight adjustable - specifically for Rotax engines to 100 hp - is currently $1400. Mounting weight with all controls and the spinner is 10 pounds.

Can that prop really provide the best of both worlds - climb and cruise?

They weigh a little more than a ground adjustable, and they can't be operated by a Sport Pilot. Any other reasons I wouldn't want one?

Re: Sensenich Flight Test Report

PostPosted: Mon Feb 16, 2015 4:05 pm
by SheepdogRD
Thank you, Paul... that helps a lot, and it makes the Ivoprop sound like a pretty good system.

You mentioned the medium IFA prop. Going from the light IFA to the medium IFA adds weight (from 9.5 pounds to 19.2 pounds), and cost ( from $1400 to $2740). Are there enough advantages to the medium to justify twice the weight and almost twice the money?

Re: Sensenich Flight Test Report

PostPosted: Mon Feb 16, 2015 6:49 pm
by av8rps
The ultralight version is certainly lighter, and less costly. But the medium is a much nicer prop.

And while the UL blade will work with the 912ULS, the medium is much more appropriate. The IVO UL blade will cavitate on initial throttle application, but it doesn't if used on the 80 hp 912UL. I think that is just a function of how light, narrow, and thin the blade is. To most the UL blade will appear to be downright flimsy, but in reality it is designed to flex a lot, which is what I believe makes it so efficient.

The medium blade is much sturdier appearing, so therefore heavier. And while it will still flex as it needs to, it is still sturdy enough to handle the higher horsepower of the 912ULS.

If I wanted to run an ultralight IVO IFA version to save weight and cost (vs the medium), I would order the IVO UL blade they call the "Patriot" blade. It has more built in pitch than the regular UL blade, has more efficient tapered tips, and is the most capable of handling the horsepower and torque of the 912ULS. A friend of mine flies that blade on a 912UL, but it won't go flat enough for that engine to get max takeoff performance. So it is not the blade to have for the 80 hp 912. I'm thinking they probably designed that blade for the 912ULS before developing the medium blade for the 912.

With all that said, with what we have been learning about different props lately, I'm not so sure it is worth giving up LSA options for the IFA prop. We are seeing some pretty good performance from some of the props being used. Especially the Prince and the Sensenich lately. When we start seeing 116 mph top speed from 912ULS Highlanders, while still having 1300 fpm climb rates, I think those blades might be even more efficient than the IVO's? And even though the IVO IFA can be adjusted, I'm not so sure it would be worth giving up on LSA, or adding the complexity of an IFA?

Mark, can you tell us how that Highlander you fly with the IVO medium ground adjustable performs? I know Howard loved that prop on floats, so I'm guessing it should do well even without the IFA option installed when on wheels.

Re: Sensenich Flight Test Report

PostPosted: Mon Feb 16, 2015 7:55 pm
by Jack L
What do you guys mean by giving up LSA options?

With regard to airspeed and propellers, our pitot static systems are not calibrated so be careful not to put too much creedance in IAS. The IAS on all of our aircraft will vary.

Jack

Re: Sensenich Flight Test Report

PostPosted: Mon Feb 16, 2015 9:31 pm
by FlyerChief
Hi Jack,
I'm sure they meant to say that the in-flight adjustable prop is not allowed under LSA rules, just like advanced ultralights in Canada. Their planes would have to be registered as experimental to use an IFA prop as do ours under the amateur-built rules.
Dan

Re: Sensenich Flight Test Report

PostPosted: Tue Feb 17, 2015 11:50 am
by av8rps
Jack L wrote:What do you guys mean by giving up LSA options?

With regard to airspeed and propellers, our pitot static systems are not calibrated so be careful not to put too much creedance in IAS. The IAS on all of our aircraft will vary.

Jack


Yes, I do realize that our IAS numbers can be all over the place with these homebuilt airplanes. But if it is even close to accurate, we have come a long ways with these Highlanders. I did verify my Highlander at 108 mph at 5450 rpm with a 912uls using an open tube landing gear with 8.50 tires and a sensenich 2 blade set more for climb than cruise. So I don't think it would be that hard to get another 8 mph. But I haven't tried that yet. But maybe I'm a bit too optimistic...

It wasn't that long ago that we had people on this forum talking about getting past 85 and 90 mph. But now we are getting much higher numbers that turn these fun airplanes into fun little traveling machines. Andn in my opinion, the combination of more efficient props and a little streamlining here and there seems to be the core to that success.


Paul