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e-Prop Pitch

rpigeek

rpigeek

Active 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
 
scottmillhouse said:
Since it is the front side that should be 63.5 from back side that relates to Vans suggested 71.4 or my 70.0. So it is a narrower thinner blade at a coarser pitch. Would like to know more about how this works.
Click to expand...
You can't compare the angles of the two props. The reference for the Sensenich is the longeron, reference for the e-prop is the spinner plate or engine. Also the position on the blades and the tool is different. You are correct that it is a narrower thinner blade at a coarser pitch.
With the Sensenich pitched fine you can get a very good take off performance and climb but you loose 10kts in cruise because the rpm redlines before WOT. If you pitch for cruise your take-off performance is far less than good. With the e-prop there is only a small gap between take-off and cruise rpm. I now have the same take-off performance as a fine pitched Sensenich but the cruise WOT is 17kts higher (110 vs 127). Climb is about the same as a fine pitched Sensenich. Also during descent you can keep higher speeds while the rpm doesn't redline.
I also will not go back to the Sensenich and that is mainly due to the smoothness off the prop, the gain in performance is a nice extra.
The 'stability' in rpm during turbulence and the 'ESR' effect is explained in the underneath youtube clip and links;

Youtube E-prop ESR effect

ESR effect explanation

Pitch adjustment e-prop
 
Thanks for the back ground information. I may switch with all the good I’m hearing. What about prop balance? My Sensenich 2 blade appears to need to be balanced with harmonics at some lower load RPMs. Just have not done balance yet. Have always wanted to swap to a CS once Mosaic kicks in. This prop appears to perform similarity. Anyone have one installed in the Southeast that I can check out?

Never mind. Got sold on the prop and have one on order. I will stride to do an apples to apples comparison and be a resource for others considering the swap.
 
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scottmillhouse said:
Thanks for the back ground information. I may switch with all the good I’m hearing. What about prop balance? My Sensenich 2 blade appears to need to be balanced with harmonics at some lower load RPMs. Just have not done balance yet. Have always wanted to swap to a CS once Mosaic kicks in. This prop appears to perform similarity. Anyone have one installed in the Southeast that I can check out?
Click to expand...
My Sensenich was dynamically balanced with a Dynavibe prop balancer. The vibration reduced to almost zero but when touching the instrument panel during flight you always felt some vibration. The e-prop is only balanced static but no vibration at all. According e-prop dynamic balance is not needed. I still want to balance the prop with the Dynavibe just to see if there is any unbalance.
Startup and shutdown also improved and no 'clunk' at shutdown. The only thing is the prop is much lighter in weight, check your CG after install. The Sensenich hub is the same weight as the complete e-prop (hub/blades/spinner)
 
Agree on the vibration from the Sensenich to the e-Prop. I haven't dynamically balanced the e-prop yet, as it's pretty good as-is. But still plan to.
 
The E-Prop three-blade looks very intriguing. Has anyone had any issue with an E-Prop three-blade on a legacy RV-12 (912-ULS) particularly with respect to removing and installing the lower cowling during maintenance? Any physical mods to the lower cowling required or suggested?
 
Just installed my e-prop, they said set pitch at 27 but based upon these posts I started with 26, way too coarse. Could get 5300 static but climb out was slow and at about 5100. Dropped to 25 and climb improved but could not get to 5500. Ended up about 5400 and around 126 knots TAS after a long slow build up. Going to try 24 tomorrow. Are you all putting the gage on the metal leading edge protection, edge where it stops or am I checking it wrong?

Result- The prop gauge was off by almost by about 1.3 degrees so the tests actually were at about 27.3, 26.3 and 25.9 degrees. I settled on an actual 25 degrees that comparers to Rpigeek's posted results.
 
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Scott, I can't give you much help with this since I just ordered my e-prop a week ago. I can tell you when I was talking to Larry to order it, he said that I should set my prop up at 24°.and not 27 as instructed. Keep us posted on your progress.
 
scottmillhouse said:
Are you all putting the gage on the metal leading edge protection, edge where it stops or am I checking it wrong?
Click to expand...
On the metal leading edge where it stops on the upgoing blade.
I received a form from France with the initial angle 26.5º. I didn't change it since. Static 5400 (MSL), climb 5200, WOT 2500' 5550RPM.
You won't get your climb RPM up to 5500, the only RPM that really counts is the WOT level flight (see below)
Initial static RPM between 5000 and 5800 -> make a flight. Test WOT RPM at 2500'. Adjust according 06º/100RPM.

Schermafbeelding 2024-10-23 om 09.46.27.png​



Schermafbeelding 2024-10-23 om 09.27.45.png
 
Just posted initial results in thread “E-prop in the southeast”. Prop balance tool became erratic so it needs to be adjusted flatter, still too coarse with RPM too low and speed too high.
 
Updated flight test results posted in thread “E-prop in the southeast”, also I know a number of RV-12 drivers are interested in changing props, especially with the recent prop SB. I've talked to Larry at Evolution and he will offer a special rate of $2500 total delivered with the new prop gauge and spinner included for Vans through the prop pitot until 1 January for the group. Cheaper if you relocate the pitot to the wing. About a $500 savings. Just mention scottmillhouse on order to get special rate. (I gain nothing, just interested in sharing a good deal)
 
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