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Converting N159SB from FP to CS...the complete story

Awesome!

Great stuff Brantel! Congrats on the successful upgrade and great write-up! Where were you 3 years ago when I was trying to figure out how to convert mine (before it first flew)?

The blended airfoil is gorgeous!
 
Glad it all worked Brian. I had the governor set at 2680 because some prop guru in a land far far away told me that it was fastest just a tad below redline.. May be old wives tale..
Glad you got it all done.
 
Brian,

I'm guessing the speed comment was tongue in check, but I would be very interested in hearing the speed difference between the Hartzell and Sensenich. Your pitch was 85, correct?

Thanks,
Scott
YA
 
tx_jayhawk said:
Brian,

I'm guessing the speed comment was tongue in check, but I would be very interested in hearing the speed difference between the Hartzell and Sensenich. Your pitch was 85, correct?

Thanks,
Scott
YA
Click to expand...

Yes and yes. I hope to get some speed runs this week.

With the FP, 174-176kts TAS was about all I could get @ 8000ft WOT 2700 RPM.
 
Congratulations Brian - don't let your face crack from the "even bigger" RV grin !

BTW, back on your comment, "I got the impression that the FSDO and the DAR thought I was a moron for following the rules" - I had a similar experience with the State Board of Aironautics when filing papers for my runway. They asked why I had not sent th papers in earlier and I explained that their forms clearly say that I needed my FAA evaluation *before* submitting to the state. Their replay was, "Oh. Yeah. No one pays attention to that."

Anyway, now I'm wishing I had a Blue Knob!
 
Just a suggestion. Where the safety wire crosses the flanges on the prop hub, over time the wire can eventually cut into the flange due to vibration. If this happens, the prop hub is "throw away".
Many people sleeve the safety wire with nylon-flow, or some similar, tubing.

As far as notifying the FSDO; changing from F/P to C/S or vice versa, a new 8130-6 is required to update information in Oklahoma City.
If changing F/P to F/P or C/S to C/S, the notification is only to confirm test area.
 
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Mel said:
Just a suggestion. Where the safety wire crosses the flanges on the prop hub, over time the wire can eventually cut into the flange due to vibration. If this happens, the prop hub is "throw away".
Many people sleeve the safety wire with nylon-flow, or some similar, tubing.
Click to expand...

You mean like this:

null%255B1%255D.jpg


On the helicopters I used to maintain, they had this stuff all over the place. We called it spaghetti.

I saw many warnings in the archives to use something similar on this wire so I put it on when I installed the wire.
 
Brantel said:
Click for bigger version:
Click to expand...

Thanks for the GREAT writeup Brantel, I've been following along on the edge of my seat. Do you happen to have the same performance chart of takeoff with the FP prop? Would love to see those side by side!

-jon
 
mosquito said:
Thanks for the GREAT writeup Brantel, I've been following along on the edge of my seat. Do you happen to have the same performance chart of takeoff with the FP prop? Would love to see those side by side!

-jon
Click to expand...

Here is a similar chart log with the FP prop....

Click for bigger:
 
Brantel said:
You mean like this:

null%255B1%255D.jpg


On the helicopters I used to maintain, they had this stuff all over the place. We called it spaghetti.

I saw many warnings in the archives to use something similar on this wire so I put it on when I installed the wire.
Click to expand...

EXACTLY!
Thanks for posting picture.
 
Mel said:
EXACTLY!
Thanks for posting picture.
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You guys are a pain. Now I am going to have to re-safety my prop. Well, I knew it when I saw Brian's pic that it was a good idea. guess I will have something to do this weekend before launching for Osh, 7-31.
 
AltonD said:
You guys are a pain. Now I am going to have to re-safety my prop.
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Yep, me too.

Would a gob of RTV work as a vibration isolator------just put it on the area where the safety wire crosses the hub???
 
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One weird thing that has changed since switching props...

With the FP during mag checks, running on the Mag only would drop about ~50 rpm. Running on the P-Mag only ~10 rpm.

Now with the CS, running on the Mag only drops about ~60 rpm. The P-Mag only drops about ~50 rpm.

Nothing changed on the ignition, no ignition components were removed, no timing adjustments were made.

Why does the P-Mag now drop ~40 rpm more? I noticed that the higher the RPM during the Mag check, the less the P-Mag dropped.

I know there is more inertia involved now and less load on the engine at typical mag check RPM of 1700 RPM but would this make the difference?
 
What is the manifold pressure change? I don't know anything about P-mags but I assume they adjust timing for MP. That could be a factor.

On the -6 I bought the failure of the Electoair ignitions manifold pressure sensor caused the rpm drop to go from perhaps 10 to about 60. Don't know how that may relate, just a data point for you.

Enjoy the performance!

Doug
 
Brian, just curious, are you setting up the stops to avoid the possibility of exceeding 2700 rpm during the takeoff roll? If so, I am curious why since Lycoming defines momentary overspeed as <10% over redline for less than 3 seconds. You only need to be concerned if you exceed the 10% for more than 3 seconds:
http://www.lycoming.com/support/publications/service-bulletins/pdfs/SB369L.pdf

With my CS prop, I often see a bit of momentary overspeed during power application on the takeoff roll (especially if power is applied rapidly) and have never been concerned about it given the guidance in Lycoming SB 369.
 
Noah said:
Brian, just curious, are you setting up the stops to avoid the possibility of exceeding 2700 rpm during the takeoff roll? If so, I am curious why since Lycoming defines momentary overspeed as <10% over redline for less than 3 seconds. You only need to be concerned if you exceed the 10% for more than 3 seconds:
http://www.lycoming.com/support/publications/service-bulletins/pdfs/SB369L.pdf

With my CS prop, I often see a bit of momentary overspeed during power application on the takeoff roll (especially if power is applied rapidly) and have never been concerned about it given the guidance in Lycoming SB 369.
Click to expand...

No, while a real OS as defined by Lycoming might happen if you had a mismatched prop/engine, I doubt it is possible with these normal configurations. (talking on the ground or during the initial takeoff roll here, in the air it is entirely possible!)

The research I did gives priority to properly adjusting the low pitch stop for the following reasons. They seem to be valid reasons so I decided to follow the recommendations:

  • Reduces the surge you get when on the takeoff roll before the governor catches up.
  • Reduces excessive prop disk drag in the event of an engine/governor/control cable failure where the prop goes fine.
  • Ensures the prop can produce enough thrust without exceeding redline in the event of a prop control failure where the prop goes fine
  • Reduces the risk of a OS event in the event that oil pressure is lost in flight for short durations
  • Both Hartzell and the governor manufacturers recommend it be set properly to 2600-2650 RPM static
 
Brantel said:
  • Reduces the surge you get when on the takeoff roll before the governor catches up.
Click to expand...
Aww, I love that surge when your head gets thrown back on T/O!
memorex-ad-2.jpg


Now that's 2 things I have to address (safety wire being the other) as a result of this thread! Very educational writeup, BTW...
 
Today I finished the 4th hour of Phase I testing. I have done a few speed runs to compare with my past performance with the FP.

Many people say that the Hartzell BA CS has little to no advantage over the 85" pitched metal Sensenich on an O-360 when it comes to top end speed.

I can say that I am right in line with the same top speed I was seeing with the FP. Seems the sweet spot on this Hartzell is somewhere around 2675 RPM at the DA I was at.

I was able to pull 174kts TAS WOT @ 2675 rpm with a DA of 4635ft with the CS and that is very similar to what I would have done with the FP.
This thing was guzzling 15.6 GPH during that run...so I am not sure I was at best power mixture, I think I was still a little rich.

Granted my airplane is not optimized for speed. I have a few Go-Pro mounts that could be removed and stuff.

Looks like I can confirm what those folks say about the top end speed performance of the two props. Same airframe results in similar top end speed numbers.

I know that this:

2zpum40.png


Put a damper on my plans today and caused me to have to sit at a nearby airport for almost an hour waiting it out. It was moving so slow that I was afraid it was going to block me from both of my best options for airports. So I picked the one close to my house to wait it out in case I had to leave the plane overnight...
 
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that looks pretty rich to me. I think you're leaving some power on the table.

with your FP at 4500'DA and 2675rpm what was your Fuel flow?
 
hydroguy2 said:
that looks pretty rich to me. I think you're leaving some power on the table.

with your FP at 4500'DA and 2675rpm what was your Fuel flow?
Click to expand...

The more I look at the data I think you are very right Brian. I am having to develop new leaning techniques because the old ones for FP don't seem to work the same now..

I looked at my logs and the closest I can come is this one with the FP: 3000'DA 2720 RPM 174kts TAS 16GPH
 
hydroguy2 said:
I know you have the data stored somewhere. What's your peak EGT? and what was it during this test?
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Brian, I have the logs from every flight since the new G3X install.

I was mistaken on my FF during my top speed test, it was 15.6 GPH after I had leaned. The 17.2 was prior to leaning.

Peak on #1 was 1520°, during this test I was 1425° on #1. I understand that best power is 125° ROP.

My problem is that with my carb, I have to compromise due to the wide spread on the other cylinders.

I will eventually find the happy place to run like I did with the FP.
 
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Foretelling the obvious....

Brantel said:
My problem is that with my carb, I have to compromise due to the wide spread on the other cylinders.
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Lets see here, first you upgrade the panel, and then the prop----------

Carnac says the next upgrade is going to be F.I.

the-tonight-show-starring-johnny-carson-carnac-the-magnificent.jpg
 
With a trip to Osh and back under my belt with the new prop, I can say that I am very well pleased with the new performance of the setup!

The other half of our two ship has a FP Sensenich just like I had and he tells me that his impression is that I am at least as fast all out as I was before the swap.

The extra climb performance is just amazing. He hung with me during some serious cloud avoidance but before my swap I would have been much more limited by CHT's. He must have some better baffles/seals than I do! Now I can climb like crazy even at altitude and this makes for a happy me.

Takeoffs are a rush! Landings are awesome due to the built in air brake!

Power on high rate descents are super cool. Free airspeed!

The new CG helped when loading the plane for the trip. No worries now!

I averaged ~3 gallons less fuel burn up and similar back than he did. He as an injected Superior O-360 and I have a carb but we both ran ROP. This is an unexpected benefit!
 
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