Sensenich Flight Test Report

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Sensenich Flight Test Report

Postby Jack L » Tue Jun 24, 2014 2:56 pm

I tested the Sensenich 3 blade 72” propeller for 9 hours on my Highlander and have some performance data and lessons learned to share with you.

The manual that comes with the 72 inch propeller is the original manual derived for the 69 inch propeller so some of the pitch setting information does not apply to the 72 inch propeller. Sensenich provides 6 Pitch Setting Gauges that are numbered 0 – 5, the instructions state that for a 100 MPH aircraft to start by setting the pitch with gauge #3. At this setting my first WOT ground run up registered 4800 RPM, with gauge #2 and WOT I registered 5000 RPM and with gauge #1 I registered 5200 RPM. These RPMs were verified with a remote tachometer.

Both the Sensenich manual and the Rotax manual caution that Take Off RPM at WOT must be at least 5200 RPM for the Rotax 912, therefore of the 6 possible pitch options only two are useable with this length propeller. Often design engineers will set limits with a safety factor so I decided to check with Rotax tech support, Sensenich tech support and Billy Payne who is a Rotax qualified technician that does all the engine work for Just Aircraft and they all stated the same, do not to not fly with any propeller unless you are turning at least 5200 RPM on the ground. The result would be overloading the engine and robbing it of available HP; I am told that this has led to detonation and significant damage to engines thereby voiding warranty claims.

At the request of Sensenich I agreed to try gauge #1 as it was felt that as the aircraft gained forward momentum the propeller would spool up faster. I monitored pitch attitude and RPM to ensure that I did not go over 5200 RPM and the result was a shallow 70 MPH climb. The top end speed was much better but I need the climb performance as well and I do not want to overload the engine. After discussing the results with Sensenich they recommended pitch gauge #1 as a minimum for my aircraft.

The numbers registered on the attached PDF were flown with gauge #1. At this setting the climb out is impressive to those watching on the sidelines but I have seen better climb performance from other Highlanders. Billy believes that If I pitch down to gauge #0 that I will drop 5 MPH so I am having a pin machined with a setting between gauges 0 and 1 and will let you know how that works out.

Sensenich Pros: Made in USA, smooth and quiet, easy to adjust, 2000 hour TBO, light weight, great tech support.

Sensenich Cons: Expensive, may not be the best performing propeller choice, two useable pitch gauges.

Sensenich Test Results.pdf
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Re: Sensenich Flight Test Report

Postby scubarider2 » Tue Jun 24, 2014 9:39 pm

Thanks for such a detailed report. I was thinking about buying this prop but from what you are saying the performance does not match the cost. :roll:
Currently flying with the Rotax 912uls with a 72in 3-blade Warp Drive. :mrgreen:
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Re: Sensenich Flight Test Report

Postby RV6 » Wed Jun 25, 2014 8:28 pm

Jack
Let me know the dia of gauge 0 ....As I have a Sen 72" also with fuel injection on my 912 so this may be
good info that I can use....
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Re: Sensenich Flight Test Report

Postby Jack L » Thu Jun 26, 2014 5:54 am

John,

The diameter of pitch gauge 0 is .2850 and pitch gauge 1 is .3150

Could you tell me what the OD of your prop to engine flange bolts are and what the ID of the flange bushings are? Mine are significantly different which concerned me in the beginning. Two calls to Sensenich and they assured me that this was normal. Just curious if yours are the same.

Pitch Gauge 0.jpg
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Re: Sensenich Flight Test Report

Postby RV6 » Fri Jun 27, 2014 7:15 am

Jack
My prop is off site but I will try to get the numbers for ya...
Send me your E-Mail add.....
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Re: Sensenich Flight Test Report

Postby Jack L » Tue Feb 10, 2015 8:29 pm

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. Here are the numbers from today's test:

Sensenich Test Results 2.jpg


Related to speed does anyone have personal experience and know if the leading edge wrap wing is faster that the scalloped leading edge? My wing does not have the leading edge wrap and I wonder what the difference is with regard to speed.

Sorry for the poor quality of this video but it gives you an idea of my climb rates at takeoff.... not a Super STOL but not so bad regardless. The Go Pro battery died so I didn't get on board video of the take offs recorded from the ground. The ski flying is a blast, typically the tail is up in one second and I'm airborne in 4-5 seconds. Ski flying is all new to me so I am experimenting and getting the feel for various snow conditions before tempting small lakes... can't wait to get out there and go fishing.

https://www.youtube.com/watch?v=Z-WsYYbvgnw

Jack
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Re: Sensenich Flight Test Report

Postby scubarider2 » Tue Feb 10, 2015 9:46 pm

Jack, thanks for all the info. I GOT MY PROP! BEAUTIFUL!!! :mrgreen:
Mine is a 68in 3-blade. Would you recommend starting at the #3 or #5 pitch?
See picture...
Dennis
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Re: Sensenich Flight Test Report

Postby Jack L » Wed Feb 11, 2015 5:20 am

Hi Dennis,

They are a nice propeller and you can't beat receiving it 4 days after placing your order!

The manual says 3 for climb and 5 for speed so start at 4 to see what your static RPM is and go from there. Maybe Pat Caron can tell us what setting he is on. Be sure to check your tracking before starting, the blades should track within 3/16" and I also like the I Handy level APP on my IPhone to double check the degrees of pitch on each blade. There should be a flat spot 9 - 10" in from the tips where you will get an accurate measurement.

I can't wait to hear what you think.

Jack
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Re: Sensenich Flight Test Report

Postby carpat » Wed Feb 11, 2015 2:31 pm

Hi Dennis,

Jack is right with the pitch pin set at 4. I started at 3 and got a static at 5450 rpm and a WOT level flight at 5750 rpm in warm summer air. So I reset the pitch pin to number 3 and now I have 5250 static rpm and 5650 WOT rpm. I flew yesterday in a clear blue sky and the temp was -7c with 30.12 altimeter. At 3000ft I had those speed:

5200 rpm = 105 mph IAS
5300 rpm = 109 mph IAS
5400 rpm = 112 mph IAS
WOT 5650 = 116 mph IAS

Climb rate was at 55 mph at about 1200 -1300 FPM. Hope that helps...

By the way, I have a little question for you guys. Yesterday I've been cruising around for about 1/2 hour and noticed that the speed wasn't there when I realised that I forgot to retract the flaps after take off. They were set at the first notch. I inspected everything once landed and didn't find anything to worry. Should I be worry or our flaps system is built to face that situation?

A good reminder to always use checklist in all flight phase.

Pat
Sorry guys for my limited English.
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Re: Sensenich Flight Test Report

Postby scubarider2 » Wed Feb 11, 2015 3:31 pm

Thanks for your help Jack and Pat. I will start at a #3 and am shooting for a 5200rpm at takeoff roll. I want all the speed it can give me. :mrgreen:
And Pat, if you did damage to the flaps you would be able to tell pretty easily from the exterior.
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Re: Sensenich Flight Test Report

Postby scubarider2 » Wed Feb 11, 2015 5:31 pm

Jack, was that you that called? The message was all garbled up. :? I heard something about settings #3 and #4. But that is all I made out. Do you recommend I start with a #4 if I want cruise speed over climb?
Thanks.
Dennis

Pat you can chime in too. I do have the iPhone app that Jack recommended.
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Re: Sensenich Flight Test Report

Postby Jack L » Wed Feb 11, 2015 7:04 pm

Denis,

That was me calling from a remote area and I was recommending pitch pin 4 for speed. I think Pat agreed and may of had a slip of the fingers stating "So I reset the pitch pin to number 3" because he started at 3 and had too high a static RPM, he changed it to pitch pin 4 which gave him a static RPM of 5250. For the Sensenich the lower pitch pin numbers provide greater climb while the higher pin numbers provide more speed.

Jack
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Re: Sensenich Flight Test Report

Postby carpat » Thu Feb 12, 2015 1:55 pm

Dennis,

Sorry I made a mistake when I typed the post. I started with pin 3 and then the pin 4. The pin 4 will give you speed and a good climb rate.

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Re: Sensenich Flight Test Report

Postby MarkZ » Fri Feb 13, 2015 11:48 am

Not to derail this thread but the only experience I have in a Highlander is behind a 912/Ivoprop combo and it seems to be a perfect match. Any comment?
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Re: Sensenich Flight Test Report

Postby Jack L » Fri Feb 13, 2015 3:58 pm

Mark,

Unless someone has flown with both props it is difficult to compare or comment. There are a lot of propeller posts on this forum and people are generally promoting the brand they fly, fortunately for all of us we have so many to choose from. I am not so sure that the perfect match exists, if it did, everyone would be flying it.

The IVO is heavy and if you do a Google search on "IVO propeller mass moment of inertia" you will find that the IVO Medium exceeds the Rotax recommendation. To some that doesn't matter and to others it does. The answer to the perfect propeller is so subjective.

Jack
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