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  #11  
Old 09-22-2017, 07:25 AM
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DonFromTX DonFromTX is offline
 
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Thanks Scott, that is the info I needed. I was unable to get that from the archives, and supposed it was not a Vans option. Sensenish sold me on their idea that the old nylon button was not accurate, but that the new pins were to be totally accurate. I guess that is not the case. I have the Sensenish blade angle tool, guess I will have to fine tune the settings that way.
Quote:
Originally Posted by rvbuilder2002 View Post
It has been discussed in the archives in the past.
As Tom mentioned, pin 3 is the recommended starting point.
The difference between each pin # is quite a bit so most people end up somewhere in between.
Since a smooth running engine requires blades to be pitched within .1 degrees of each other, you have to measure it. Neither the old style or new style hub gets the blade pitch relationship accurate enough.
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  #12  
Old 09-22-2017, 08:33 AM
rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by DonFromTX View Post
Thanks Scott, that is the info I needed. I was unable to get that from the archives, and supposed it was not a Vans option. Sensenish sold me on their idea that the old nylon button was not accurate, but that the new pins were to be totally accurate. I guess that is not the case. I have the Sensenish blade angle tool, guess I will have to fine tune the settings that way.
The current Rev. KAI section for propeller installation mentions using pin 3 as the starting point.
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  #13  
Old 09-22-2017, 08:47 AM
rvbuilder2002 rvbuilder2002 is offline
 
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[quote=AirHound;1205923]
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Originally Posted by rvbuilder2002 View Post
I agree it sounds just a bit too course, but maybe Tom is cruising around down low at 125 kts and just not telling anyone

Hi, I'm Doug in IL. In bound is hub replacement IAW theSeninich B revision exchange program. I bought my 12 built/used and it had a dynamic bal job 3 years ago. What to do now. I don't have dynamic balance capability nearby? Any suggestions opinions welcomed. I took the B hub off because of a 1.15 dif in blade angle and it's a b hub??
From my experience, anytime a propeller is removed from an engine (Rotax, Lyc., etc.) and then reinstalled, it will have some level of influence on the overall balance and that rechecking the dynamic balance afterwards is typically warranted.

If that wont be possible, you can label all of the parts positions so that is gets reassembled with the blades and the spinner reinstalled in the exact same clocking positions on the crank shaft and see what happens. If it feels as smooth as it has previously then you could just leave it as is. If not, then finding someone to check the balance would be a good idea.

P.S. I am somewhat hesitant to recommend this because physical evaluation of smoothness is very subjective. The only truly accurate way to know is to measure it. Having engine vibration low in an aircraft has many benefits far beyond passenger comfort (airframe longevity, etc.), so knowing for sure that the vibration level is as low as possible is worth traveling to have it checked in my opinion.

Also keep in mind that a very close match in blade pitch has a major influence on smoothness. Doing a dynamic balance without confirming that the pitch of the blades is within .1 degrees of each other is a waste of time and money.
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  #14  
Old 09-22-2017, 12:34 PM
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Quote:
Originally Posted by DonFromTX View Post
Sensenish sold me on their idea that the old nylon button was not accurate, but that the new pins were to be totally accurate. I guess that is not the case. I have the Sensenish blade angle tool, guess I will have to fine tune the settings that way.
I wouldn't even use Sensenich's blade angle tool. I would get the sheetmetal pitch gage from Van's. Very accurate and repeatable...
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  #15  
Old 09-22-2017, 03:07 PM
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Default I don't think it can get any closer by the gage method

I know that there people that think that they can set the prop angle better with a pitch gage and maybe they can.
The pin setting method is in my view as close as 95% of the all the props set with a gage
The pin method is designed to change two inches of bite in one revolution .
If you want something in the middle you can turn down the larger pin to the one half the difference in the next smaller pin.
I have reviewed this possess add I don't think it can get any closer by the gage method
I went to Sensenich for a Factory tour on 09/06/17 for this same question.



The story I posted on our chapter 1298 web page

http://eaa1298.com/Members/1298_FS_09_06_17.html

MY view

Joe Dallas
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Last edited by joedallas : 09-22-2017 at 03:13 PM.
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  #16  
Old 09-22-2017, 03:30 PM
smithflys23 smithflys23 is offline
 
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I'm going to be pretty upset if the pin system is not accurate. I paid a premium for this prop over the Whirlwind GA, because this pitch pin system promises easy pitch adjustments.
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  #17  
Old 09-22-2017, 04:07 PM
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Default 1 tenth of a degree is .0017 in a inch.

Scott is dismal point on the wrong side of the 1 ?

1 tenth of a degree is .0017 in a inch.

Joe Dallas


[quote=rvbuilder2002;1205961 Also keep in mind that a very close match in blade pitch has a major influence on smoothness. Doing a dynamic balance without confirming that the pitch of the blades is within .1 degrees of each other is a waste of time and money.[/QUOTE]
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  #18  
Old 09-22-2017, 04:08 PM
AirHound AirHound is offline
 
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[quote=rvbuilder2002;1205961]
Quote:
Originally Posted by AirHound View Post

From my experience, anytime a propeller is removed from an engine (Rotax, Lyc., etc.) and then reinstalled, it will have some level of influence on the overall balance and that rechecking the dynamic balance afterwards is typically warranted.

If that wont be possible, you can label all of the parts positions so that is gets reassembled with the blades and the spinner reinstalled in the exact same clocking positions on the crank shaft and see what happens. If it feels as smooth as it has previously then you could just leave it as is. If not, then finding someone to check the balance would be a good idea.

P.S. I am somewhat hesitant to recommend this because physical evaluation of smoothness is very subjective. The only truly accurate way to know is to measure it. Having engine vibration low in an aircraft has many benefits far beyond passenger comfort (airframe longevity, etc.), so knowing for sure that the vibration level is as low as possible is worth traveling to have it checked in my opinion.

Also keep in mind that a very close match in blade pitch has a major influence on smoothness. Doing a dynamic balance without confirming that the pitch of the blades is within .1 degrees of each other is a waste of time and money.
Thanks Scott, say do the slsa versions come off the line dynamic balanced?
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  #19  
Old 09-22-2017, 05:04 PM
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DonFromTX DonFromTX is offline
 
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Me too. I chose to spend the bucks because my EAB 12 has so many differences than an ELSA, I figured I would be playing with the pitch a lot getting it all dialed in where I wanted it, and wanted the quick and easy method.
The ferry pilot (Bob Bogash) who brought my ELSA down reported it was pitched far too coarse, but I think that I will like it that way. Fuel economy was very nice and so was the ground speed. It has the old Nylon button system.
Quote:
Originally Posted by smithflys23 View Post
I'm going to be pretty upset if the pin system is not accurate. I paid a premium for this prop over the Whirlwind GA, because this pitch pin system promises easy pitch adjustments.
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Last edited by DonFromTX : 09-22-2017 at 05:21 PM.
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  #20  
Old 09-22-2017, 06:33 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by joedallas View Post
Scott is dismal point on the wrong side of the 1 ?

1 tenth of a degree is .0017 in a inch.

Joe Dallas
No, I meant 00.1 degrees

Your are of course welcome to your opinion if you think it doesn't matter.

I rarely provide info based on opinion (I try and use actual testing or in service experience).

I have seen, felt, and measured the vibration difference that more than .1 degrees of mismatch makes.

I have also measured the blade pitch differences that result from just using the pins on quite a few different props (Van's flight tested one of the early prototypes, and has sold more than a few S-LSA's so there is experience with a lot of different props.

The very first S-LSA's did not get the props Dyn. balanced, but they have been for a number of years now (not sure when exactly it was started).
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Last edited by rvbuilder2002 : 09-22-2017 at 06:36 PM.
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