rpigeek

rpigeek

Member
Just finished my e-prop installation and did a bunch of testing by flying at 3500 density altitude. I’m curious to compare this to others and what you settled on.

Baseline, old Sensenich 2-blade on an E-LSA w/ULS and no wheel pants.

PitchDensity Altitude (in Cruise)Cruise KTASCruise SettingsTakeoff RPMClimb RPMStatic RPM
Sensenich Baseline350011027”, 5500 RPM550055005500
~26.6 (Initial)350012428” WOT, 5420 RPM50005000~5200
25.83500125
121		28” WOT, 5640 RPM
27”, 5500 RPM (not WOT)		520052005490
25.1350011726.8”, 5490 RPM (not WOT)530053005590

I’m curious what others are seeing and choosing as a trade off with this prop? I’m debating keeping the 5300 climb or go back to the 5200 climb pitch. At the 5300 pitch it has a bit of cavitation until it starts rolling. I did find I can “roll in” the throttle to help with the cavitation.

It’s a nice prop. Very light and easy on the gearbox and shutdown. A lot quieter and less vibration. I haven’t dynamically balanced it yet, and suspect it won’t need anything With how smooth it is. The center pitot tube is really nice and integrates well with the spinner. Adjusting it as frustrating as any other prop you have to make small adjustments per-blade, I did find if I loosen up all the screws a half turn it’s easy to do a .5 degree adjustment, and if I loosen up the screws a quarter turn it’s easy to do a .1 degree adjustment.
 
I think your Sensenich was a bit under-pitched. I cruise “gross weight”, that will make a difference, at 5400 rpm @ 118kts in smooth air on a 2 blade Sensenich. Your climb performance, fpm difference between the two props would be interesting to compare for the rest of us.
 
seagull said:
I think your Sensenich was a bit under-pitched. I cruise “gross weight”, that will make a difference, at 5400 rpm @ 118kts in smooth air on a 2 blade Sensenich.
Click to expand...
I agree and think it could have been pitched for 5200/5300 static on the old prop.
seagull said:
Your climb performance, fpm difference between the two props would be interesting to compare for the rest of us.
Click to expand...
On the Sensenich with that pitch I was seeing 900 FPM at gross. On all the pitches on the e-prop I was seeing about 900 FPM. It’s a bit hard to read on the G3X. I’ll see if I can download logs to compare.
 
rpigeek said:
Just finished my e-prop installation and did a bunch of testing by flying at 3500 density altitude. I’m curious to compare this to others and what you settled on.

Baseline, old Sensenich 2-blade on an E-LSA w/ULS and no wheel pants.

PitchDensity Altitude (in Cruise)Cruise KTASCruise SettingsTakeoff RPMClimb RPMStatic RPM
Sensenich Baseline350011027”, 5500 RPM550055005500
~26.6 (Initial)350012428” WOT, 5420 RPM50005000~5200
25.83500125
121		28” WOT, 5640 RPM
27”, 5500 RPM (not WOT)		520052005490
25.1350011726.8”, 5490 RPM (not WOT)530053005590

I’m curious what others are seeing and choosing as a trade off with this prop? I’m debating keeping the 5300 climb or go back to the 5200 climb pitch. At the 5300 pitch it has a bit of cavitation until it starts rolling. I did find I can “roll in” the throttle to help with the cavitation.

It’s a nice prop. Very light and easy on the gearbox and shutdown. A lot quieter and less vibration. I haven’t dynamically balanced it yet, and suspect it won’t need anything With how smooth it is. The center pitot tube is really nice and integrates well with the spinner. Adjusting it as frustrating as any other prop you have to make small adjustments per-blade, I did find if I loosen up all the screws a half turn it’s easy to do a .5 degree adjustment, and if I loosen up the screws a quarter turn it’s easy to do a .1 degree adjustment.
Click to expand...

Can you elaborate a bit more on your observation of cavitation? I typically associate that term with water props that are generating bubbles of water vapor when they deliver too much power for the situation. What does cavitation mean for a prop operating in air? How can you tell, etc. ?


Thanks in advance,
-dbh
 
I'll be following this thread closely to see the performance changes as you dial in the E-prop.

Did the forum ever reach a resolution on the legality of installing this E-Prop (CS Variable Pitch) on a United States Based E-LSA? If I recall some of the posters here mentioned that installation may totally invalidate the Ops Limits for an E-LSA or at least require a new issuance. Or worst-case scenario may be entirely prohibited in the US...

Interested to hear yalls opinion!
 
Has anyone done a pitch comparison on the Sensenich 2 blade prop that we can directly compare to the e-prop? It appears his installation was greatly under pitched like mine was for initial installation per Vans recommendation. As I recall they said 71.4 and I kept making it coarser ending up with 70. Not sure why it is off so much, perhaps my level. Seeing 120 now at 5490, 4600’ density altitude and 118 at 9000’. Lost some climb performance but cruise is now at 115 around 5300 about where I think I want it. I’ll down load data from Dynon and see if I can summarize my recent efforts.
 

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I looked up some of my past flights with differing pitches. The Vans pitch at 71.4 was similar to his at 111-113 TAS with my current pitch at 119-120. RPMs went down as well as climb rate. Kind of apples to oranges comparison with different days, temperature and altitudes but you can see the trend. Results to me are more similar to the e-prop than as represented.

PitchrpmTASPALvertical speed
70​
5276​
83​
510​
850​
5471​
119.4​
3200​
0​
5498​
119.3​
7400​
0​
70.9​
5347​
85​
1300​
910​
5501​
116.5​
3800​
0​
5480​
116​
5100​
0​
71.4​
5305​
79​
1200​
919​
5534​
113​
7500​
0​
5489​
111​
7500​
0​
 
Still begging for someone who is planning this change to fly the 10,000 climb and speed box tests that are published by Van's and referenced in the PAP. That would let us normalize some of this with respect to climb/cruise pitch as well as the temp changes. This would take a big bite out of the apples and oranges thing.

I know, new prop shows up and it's hard to have the patience to go test fly the old one again.
 
I did the PAP tests but decided they are worthless until you have your pitch refined to where you want. With the added bite I now can not do the 70 knot climb to 10000’ and have rpm above the Rotax target of 5200, 75 is possible but 80 is more realistic.

I don’t understand how for both props one can get a static of 5500 on the ground and then get over 120 knots on the e-prop. Does the e-prop change pitch under load by blade deflections? Even at my flattest setting the Sensenich would do less than 5300 until take off. Then you set the rpm by climb speed If too flat you could red line it. As an example depending on my pitch a 5200 rpm climb could be 60 knots or 80.
 
dbhill916 said:
Can you elaborate a bit more on your observation of cavitation? How can you tell, etc. ?
Click to expand...
It makes a sound that sounds like cavitation in a boat and doesn’t really bite. If you ”roll in” the throttle it’ll bite more than just holding brakes with a wide open throttle.
 
scottmillhouse said:
I don’t understand how for both props one can get a static of 5500 on the ground and then get over 120 knots on the e-prop. Does the e-prop change pitch under load by blade deflections?
Click to expand...
Yes, that's exactly how it works. It flexes and changes pitch depending on load. On takeoff roll, if you are holding breaks it will be 5,600 RPM yet once it moves 100 feet it'll drop to 5,300 RPM as an example.
 
I did a bit more testing today on it.
Pitch: 25.1 degrees
Static RPM: 5,600'ish
Takeoff Roll RPM: 5,300'ish
Climb RPM @ 65 KIAS: 5,300'ish
Ground Temp: 65-70F (about 15 degrees cooler than last time)
No fairings or wheel pants

With this I saw about 1,200 FPM at sea level at 65 KIAS

The following are all at about 5500 RPM.
AltitudeDensity AltitudeKTASManifold
1500210011927.1"
2500290012026"
3500400012025.2"
4500490012024.3"
5500590011923.5"
6500710011822.8"
7500810011822.1"
8500930011821.2"

I suspect the Sensenich would also perform a lot better at this temperature.

What's interesting is lower is better for the prop, likely it responds better to more bite. I may add a half degree to the pitch to have the climb be at 5200 RPM. I'll be adding wheel pants and leg/interface fairings so likely I'll wait to re-pitch it then in a couple months.

vs. the Sensenich
* I won't going back, it's just so much quieter and easier on the gear box
* With how I have it pitched I'm seeing about the same takeoff & climb performance with more top end
 
N8DAV8R said:
I know, new prop shows up and it's hard to have the patience to go test fly the old one again.
Click to expand...
Unfortunately, I have no desire to swap these props on/off for an apples to apples comparison. I do wish I had the foresight to do some of this testing with the old prop before installing the new prop. The ESR behavior of the prop makes it hard to compare comparable static, climb and cruise performance.
 
rpigeek said:
Just finished my e-prop installation and did a bunch of testing by flying at 3500 density altitude. I’m curious to compare this to others and what you settled on.

Baseline, old Sensenich 2-blade on an E-LSA w/ULS and no wheel pants.

PitchDensity Altitude (in Cruise)Cruise KTASCruise SettingsTakeoff RPMClimb RPMStatic RPM
Sensenich Baseline350011027”, 5500 RPM550055005500
~26.6 (Initial)350012428” WOT, 5420 RPM50005000~5200
25.83500125
121		28” WOT, 5640 RPM
27”, 5500 RPM (not WOT)		520052005490
25.1350011726.8”, 5490 RPM (not WOT)530053005590

I’m curious what others are seeing and choosing as a trade off with this prop? I’m debating keeping the 5300 climb or go back to the 5200 climb pitch. At the 5300 pitch it has a bit of cavitation until it starts rolling. I did find I can “roll in” the throttle to help with the cavitation.

It’s a nice prop. Very light and easy on the gearbox and shutdown. A lot quieter and less vibration. I haven’t dynamically balanced it yet, and suspect it won’t need anything With how smooth it is. The center pitot tube is really nice and integrates well with the spinner. Adjusting it as frustrating as any other prop you have to make small adjustments per-blade, I did find if I loosen up all the screws a half turn it’s easy to do a .5 degree adjustment, and if I loosen up the screws a quarter turn it’s easy to do a .1 degree adjustment.
Click to expand...
You think air can cavitate?
rpigeek said:
Just finished my e-prop installation and did a bunch of testing by flying at 3500 density altitude. I’m curious to compare this to others and what you settled on.

Baseline, old Sensenich 2-blade on an E-LSA w/ULS and no wheel pants.

PitchDensity Altitude (in Cruise)Cruise KTASCruise SettingsTakeoff RPMClimb RPMStatic RPM
Sensenich Baseline350011027”, 5500 RPM550055005500
~26.6 (Initial)350012428” WOT, 5420 RPM50005000~5200
25.83500125
121		28” WOT, 5640 RPM
27”, 5500 RPM (not WOT)		520052005490
25.1350011726.8”, 5490 RPM (not WOT)530053005590

I’m curious what others are seeing and choosing as a trade off with this prop? I’m debating keeping the 5300 climb or go back to the 5200 climb pitch. At the 5300 pitch it has a bit of cavitation until it starts rolling. I did find I can “roll in” the throttle to help with the cavitation.

It’s a nice prop. Very light and easy on the gearbox and shutdown. A lot quieter and less vibration. I haven’t dynamically balanced it yet, and suspect it won’t need anything With how smooth it is. The center pitot tube is really nice and integrates well with the spinner. Adjusting it as frustrating as any other prop you have to make small adjustments per-blade, I did find if I loosen up all the screws a half turn it’s easy to do a .5 degree adjustment, and if I loosen up the screws a quarter turn it’s easy to do a .1 degree adjustment.
Click to expand...
You think you can get cavitation in air?
 
RV12M4 said:
You think air can cavitate?

You think you can get cavitation in air?
Click to expand...

You will find if you look around that the e-prop defies physics in mystical ways that can always be described but never measured.

I kid because I'm interested and just wish someone would be the guinea pig so I won't eventually have to myself.
 
WJaviation said:
Did the forum ever reach a resolution on the legality of installing this E-Prop (CS Variable Pitch) on a United States Based E-LSA? If I recall some of the posters here mentioned that installation may totally invalidate the Ops Limits for an E-LSA or at least require a new issuance. Or worst-case scenario may be entirely prohibited in the US...
Click to expand...
Now, no. Cannot legally fit an in-flight adjustable prop to any LSA.

Check back in 1-2 years once MOSAIC is in effect and they will be legal in all LSAs, as the FAA has recognized they are not THAT more complicated to operate, and are a safety tool since more power can be extracted.
Automatic prop control doesn’t require any training (an option if you have a 912is).
Manual prop control will require an instructor endorsement if you are flying as a Sport Pilot.

On either RV-12, you’ll need to move the pitot out to the wing.
 
I used the 26.5º from the manual and didn't change it since. Static WOT 5400RPM MSL. 127kts at 2500ft 5550RPM WOT. 120kts at 1000ft 5200RPM.
The prop is so smooth. During turbulence I was always playing with the throttle because of RPM fluctuations with speed. With this prop it is just one setting and it stays there.
With the standard -15 spacer the space between cowling and spinner is 1/8". Really happy with this prop

tempImageCM5wTV.jpg
 
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