What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Sensenich ground adjustable prop - real world experience?

S. Soule

Active Member
I just installed a Sensenich ground adjustable prop and set the blades to "4" per the instructions. The engine is an Aerosport O-320 D2G 160 hp. The ramp is too icy for a static power test, so I thought I would ask two questions: First, what static RPM have others observed when the blades were set to "4" and second, what blade setting did others end up settling on. Steve
 
It depends on what type of aircraft it is on

On my 160 hp Rv4 I used the highest pitch pin setting 7 or 8, I dont recall off hand. The prop was still under pitched. ( I could exceed 2700 RPM in level flight at 8000 da. I eventually had the index pins on the prop changed to the 180 hp setting and after some testing ended up using pitch pin number 6. I get 2200 static and 2700 full throttle at 8000da.

Once you get it dialed in you will like the performance you get

Cm
 
My results are the same as Christopher on my 180hp RV4. Pitch number 6, static 2200, full throttle 2700. However, when they made my prop, they set my pitch pins on the prop blade a little more aggressive then standard, due to the skinny light weight airplane with 180hp. Number 6 works perfectly for me, and it’s a beautiful smooth operating prop.
 
8-9 Pin

I used different settings when I first installed the prop. RV9 IO320 D1A. Never got the top end at altitude I was looking for. Used the 7 pin but still to high RPM in cruise. One method is to set prop angle by hand with a protractor. Did it with Don down at Airflow Performance. Worked out fine, but needed to be redone every time I did an inspection and became a pain.

Called Sensenich and found out they had a 8-9 pin but didn't include it in the kit. The 8-pin was close to what I had been running when I set it by hand.

I got the drawing and had a local machinist make one, works great and I use the 8-pin setting now.

Climb performance is great, gets off in 1000 or so. Don't remember what the static was as it was not a good indicator for me of how the prop performs at cruise altitude. Never have had to reset the pitch for a shorter ground run as the RV9 and engine are well matched.
 
8-9 Pin (slight thread drift/steal)

Is Sensenich actually offering a 8-9 Pin or just the drawing and you have to make it yourself??

I am very interested as i have 2300 static and redline in cruise running on #7.

And i love this prop!!

Apologies for “highjacking” the original thread.
 
8-9 pin

Apparently, they didn't think people would need it and so, I guess, only made a few early on but never more than a few. So I couldn't buy one from them but they sent the drawing. Easy for any machinist to follow.
 
Sensenich ground adjustable prop

Hi there, I have a RV-6A with an IO-320 Lycoming with 160 HP pistons. I have a Holy Cowl, plenum, Superior cold air sump and EFII injection/ignition.

I’m using pin #8, I went through all the pins that came with the prop and was still over speeding at altitude. I spoke with Sensenich about it and they sent me the drawing for the larger pins (8 & 9). It’s an easy machining project.

I turn 2200 static and can still over speed if I don’t watch it carefully. I may try the 9 pin setting this summer when it warms up.

Terry

One more thing, the 6 and 7 pin I received was miss labeled. Check the dimensions on your pins to ensure they are stamped correctly.
 
I have about 250 hours with mine (high time 160hp O-320). It appears you are located in Vermont. If so and not operating from a very short airstrip, any pin setting will be fine to get started but I'd pick mid-range.

I'm based at 5,000' MSL. Most takeoffs/landings are performed at fairly high density altitude (7,000' and up), many above 10,000' DA. When operating from backcountry/short airstrips, I typically set the prop to the finest/climb pin/setting and takeoff/climb performance is very good, even at that high DA (though not fast at cruise). I used #7 for a couple months this summer and didn't care for it. As I recall, takeoff rpm (~7,000' DA) was around 2100. At full throttle cruise (10,000' DA) I could only get about 2600 rpm (all from memory). I suspect none of that matters to anyone as very few people routinely operate an RV-4 as I do. However; my real point that this prop offers some really nice flexibility/options if you need them - in addition to being a very nice prop (good performance, smooth, etc.).
 
I set mine at 4 (the nominal setting) on my 160hp 6A. My static RPM is 2300+. I have to be careful not to over-rev doing loops etc. But, like YellerDaisy said, you will really appreciate better take-off/climb performance if you fly in the southwest during the summer. I give up a little fuel economy but it's worth it to me. John
 
Thanks very much. This is really useful. I’ll start with the 4 setting and see how it goes. Even on a hot summer day, the DA at airports around here in Vermont don’t get much above 1,800 feet. The ramp is still too icy to get out today so I’m waiting on better conditions. Steve
 
Is it standard practice to use a prop space with the O-320 and this prop?

Yes - assuming one of the two (I think only two) standard RV-4 cowls. What you require is engine and cowling dependent. My RV-4 is very old (SN 107) with an O-320 having 7/16" bolts (crank). I needed a 4" extension (7" dia) with 7/16" bolts on both ends. Sam at Saber set me up quickly and easily.
 
I went from a fixed pitch Sensi to the ground adjustable Sensi. Was able to use my existing prop extension. The new prop required new bolts however. John
 
9A/160HP 320

I settled on 4.5 for my GA on the 9A. Pin 4 climbed, but I could easily blow through 2700rpm at 8000’DA. Now with a wrap of ‘hard’ tape around the #4 pin (hence pin 4.5), I hit 2700rpm at full rich at 8000’DA and 165 kt true. Static is roughly 2250 rpm, as I recall.
 

Attachments

  • B9AF503E-D9FE-4323-9B67-7A6682368E3B.jpeg
    B9AF503E-D9FE-4323-9B67-7A6682368E3B.jpeg
    102.5 KB · Views: 211
I suggest you mic that #4 pin with the “hard tape”, send that dimension to Sensenich, and have them make you a pin at that diameter. Tape doesn’t sound like a permanent solution.
 
Mike, I bought my fixed pitch Sensinich prop and prop extension from Vans. The extention was specific to my cowling and engine as I recall. I'm guessing the specs for the prop extension are still in th Vans catalog. Don't know which GA prop you're planning to use but would talk with the manufacturer and see if the extension Vans sells will work. John
 
I was thinking of using "hard tape" to make a micro change in the pitch if I needed to. What did you use for tape? Steve
 
Sensenich ground adjustable prop.

I’ve never heard of a Holy Cowl but I think I need to get one now. What is it? 😀

Hi Tim:

A Sam James holy cowl is an aftermarket cowling with round inlet holes. The company has been sold a few times since I purchased mine and I've lost track as to who has it now.

I remain pleased with my cowling, it works well.


Terry.
 
Are you guys referring to the 2 or 3 blade prop? I'm considering a 3 blade version but I'm pondering if having another adjustment like this is just complicating matters.
 
4.5 pin?

I settled on 4.5 for my GA on the 9A. Pin 4 climbed, but I could easily blow through 2700rpm at 8000’DA. Now with a wrap of ‘hard’ tape around the #4 pin (hence pin 4.5), I hit 2700rpm at full rich at 8000’DA and 165 kt true. Static is roughly 2250 rpm, as I recall.

I have a chart that shows the actual pitch associated with each pin setting. Im thinking a half setting would be pretty negligible Im curious how you made hard tape contour to the radius of the area of the pin that contacts the index pin on the prop. Did you measure it to compare it with. A 4 and 5 pin?

Cm
 
4.5 pin

Everything is at the hanger, but it only took one layer of tape to get me to where I ended up. I trimmed for no overlap. It only needs to be on a rather narrow place on the longest part of the pin. The tape....may have been the anti chafing tape I used for the flaps. It didn’t deform through the setting process. I had to use a little heat to get it to confirm the diameter of the pin. I’ll amend this Saturday when I get to the hanger. ** #4=0.500”, #5=0.520, my 4.4=0.508. **

If I had to buy something, I’d try Mylar foil tape or aluminum tape.
 
Last edited:
Every Van's RV-12 comes with a Sensenich ground adjustable fixed pitch prop. Van's sells a $8 steel pitch adjustment tool, combined with a digital level that allows you to set the pitch of each blade to 0.1 degree changes, or less, on the Rotax 912 ULS and 912 iS motors.

The sweet spot on these motor seems to be about 5150 to 5200 rpms at a Vy climb out rate of 75 Kts indicated airspeed.

Get a little closer to 5125 rpm, if you cruise a lot at higher altitude, and you'll sacrifice some climb rate. Use a 5200 rpm setting if there's obstacles to clear on your runway. 5150 to 5170 seems to be the best of both worlds.

Be aware that 0.3 degrees change in pitch nets 15 to 25 rpms more or less depending on more or less bite on the pitch of the prop. Vans suggests a pitch of aproximately 71.4 degrees as the best in their extensive testing.
 
Yes - assuming one of the two (I think only two) standard RV-4 cowls. What you require is engine and cowling dependent. My RV-4 is very old (SN 107) with an O-320 having 7/16" bolts (crank). I needed a 4" extension (7" dia) with 7/16" bolts on both ends. Sam at Saber set me up quickly and easily.

What did you do about your spinner? Old cowlings require a 12 inch spinner verses a 13 inch spinner on the later cowlings. Like you, I have the older cowl.
 
Yes, that is correct. I have a 13" spinner with the old cowl - so a mismatch. Sensenich does offer a 12" spinner but I haven't bothered as the existing one only bothers me occasionally.

Here's a photo I took during the prop install.

2018_12_23_RV4_SensenichProp1.jpg
 
For you guys with the ground adjustable Sensenich prop, what RPM gain or loss is associated with each change of pitch using the pitch pins that come with the prop? Steve
 
For you guys with the ground adjustable Sensenich prop, what RPM gain or loss is associated with each change of pitch using the pitch pins that come with the prop? Steve

I wish I could say that I know for certain but I don't. :-( I occasionally think of doing a serious of tests to document that for the same weight, DA, etc.

A crude estimate is 50-75 rpm.

Based on failing brain cells... (at 5,000' AGL, high-ish DA, high time O-320 (160hp), near gross weight)

Early in the takeoff roll, RPM varies from about 2450 (pin 2) to about 2100-2150 (pin 7).

At 8,000' DA and S&L, max rpm with pin 7 is about 2650, pin 6 is about 2700, the others allow me to exceed 2700 fairly easily.
 
Lots of good experience with this prop on this thread. I’ve got a vibration I’m trying to eliminate and after dynamic balancing down to .03 there is still a noticeable wobble. I noticed that my prop is not “clocked” to where it stops at the 10/4 o’clock (the hand propping position) it instead stops at 2/8. I’d be interested in hearing where others have their prop indexed to for the smoothest operation?
 
Sensenich ground adjustable prop.

I noticed that my prop is not “clocked” to where it stops at the 10/4 o’clock (the hand propping position) it instead stops at 2/8. I’d be interested in hearing where others have their prop indexed to for the smoothest operation?

Hi Jeff: Just this past weekend I was given a copy of Lycoming Service Instruction No. 1098J which deals with this very subject. There is more involved than you would think at first glance.

Be glad to email it to you if you want to PM me with your email address.


Terry.
 
My experience on Sensenich G/A prop

I was lucky that i had my prop clocked right the first time. When the engine stops, seen from the front facing the aircraft, the prop comes to a halt in the 10/4 o’clock position.
I have minor vibrations throughout the whole range but no dynamic balancing done yet. I bet on further improvements after that’s done.
I use pin #7 on my (dyno tested) 195hp XIO-360. Static Rpm is 2320-2360 depending on atmospheric conditions.
No data so far on takeoff distance and climb performance, but she behaves like a homesick angel. I am impressed every time.
Cruise data max power (WOT, ROP) ist still to be declared.
Cruise data @7500 feet, WOT, LOP was 166KTAS @ 8 US gallons/hour. RPM came out at 2650.

I wrote Sensenich after i heard about the existence of the #8 + #9 PIN. They answered within 6 hours and sent me the spec sheet of this pin. Included is a list of diameter data of the other pins. A machine shop can easily make you this or any other pin (like the 4.5 it was talked about).
I don’t publish this spec sheet here as it is still property of Sensenich.


To put it in a nutshell: i love my prop! Would not hesitate to buy anotherone!
I am still testing to find my “sweet spot”.
 
Closing the loop on my cruise vibration issue, I re-indexed the prop according to Van’s instructions that can be found in post #9 of this thread: https://vansairforce.net/community/showthread.php?t=193268&highlight=Prop+clocking WOW, I am now running smooth through the whole RPM range, maybe a little rougher at idle but will gladly trade that for the smoothness in cruise. Thanks everyone for the input, I’m going flying!

Thanks for the link. I purchased this same propeller but have been thinking about how to mount it when that time arrives. Now I know.
 
Went from 4 to 5 setting

Since I was doing the annual on my 0-320 6A and needed to remove the spinner anyway, I decided to set my Sensi. GA prop at 5 instead of 4. I've only flown an hour since, but I think my plane is much happier at 5. The takeoff run may be a little longer, but the rpms are not flirting with 2700 as often. I think I've gained 10 knots on the cruise speed and am optimistic about improved fuel economy and better cooling of the engine. I checked the static rpm at the new setting and got 2350.

John
 
RPM Info Request for RV8 with IO-360-M1B

I did my full power run on my RV8 with the IO-360-M1B with the Sensenich propeller set on pin #4.

The max RPM was 2380. There was about 1" of throttle travel left before when the RPM reached 2380 and it stayed at the same RPM at full throttle.

Is there any RV8 builder with this same set up, and what is your RPM in flight? Does it often get into the 2700 RPM range? I am thinking of increasing the pitch to pin#5 for my first flight

Thanks.
 
Back
Top