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prop pitch question

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tigerrick(at)mindspring.c
Guest

Posted: Mon Apr 17, 2006 1:25 pm Post subject: prop pitch question

Hi, Thomas!



I also have a '76 that is now equipped with a 63" pitch Sensenich, and 

it does just fine high and hot when flown right.  Dave Fletcher 

maintains that the 62" is the ideal for most applications, and I don't 

doubt him at all.  I don't have the PF exhaust either, but I'm a nut 

about engine maintenance, leaning, and a third flap on take off, so I've 

been happy with the 63" while getting all out of the O-360 that it has 

to offer.



The 64" can be repitched down to 63", but it sounds like you'd be better 

off with the 62" - fly it awhile, and if you want a couple more knots at 

cruise and a bit less climb, you could pitch it up an inch.



Just my opinion, obviously.



Rick Lindstrom

N74613

N4526B

N9738U



airman(at)appledumplings.com wrote:



 	  Quote: 	
		  



Originally sent this to the grumman-gang list with an "unacceptable  

subject line" and got bounced by the gg-list nazi. figured I would  

try here.



  



>I bought a 76 tiger and am getting a new sensenich prop. The  

>problem is that the only pitch that they have is the 64" pitch prop  

>available ... i was looking at 62"  or  63" pitch but they say 6-12  

>weeks. Repitching is extra So either I go with the 64   or i go  

>pick it up and  do the prop later.

>It doesnt have any performance mods like the power flow or anything  

>so I am unsure what the max pitch I  should consider.

>I have no experience in tigers so recommendations would be  

>helpful.   I plan to use it for my ifr training and flights back  

>and forth to in-laws  about 4-500 miles. I also will be going to a  

>sea level airport of 2300' long on and off.

>Thanks in advance,

>Thomas

>N74225

>    

>

flyv35b(at)ashcreekwirele
Guest

Posted: Tue Apr 18, 2006 6:09 am Post subject: prop pitch question

With your longer x-country flights I'd go with the 64" and see how it works. 

You can always repitch it later on or add the PF exhaust and then you 

wouldn't want to.  I doubt if a 2300 ft. strip will be a problem with a 64" 

pitch prop unless there are tall obstructions right off the end.  I have 

flown a Tiger in an out of a 1500 ft. strip in the past with a 63" pitch.



Cliff  A&P/IA

---

GrummanDude

Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA

Posted: Tue Apr 18, 2006 10:52 pm Post subject: prop pitch question

Most Tigers won't do very well with a 64" pitch.   The original blank, if I'm 

not mistaken, is made with a 62" pitch, so, it's already been twisted 2 

inches.   If you twist it back 2 inches, that's 4 inches it's been twisted already. 

  It can only be twisted a total of 8 inches ........    So, with that said, 



Depending on how strong your engine is, I'd see if I could get a custom twist 

with the twist at 64-62-60.   The average is 62 which is a legal pitch for 

the Tiger.   But, you get back about 75 to 100 rpm and you don't give up much in 

cruise.   maybe 2 knots.

_________________
Gary
AuCountry Aviation
Home of Team Grumman

bruce.smith(at)york.com
Guest

Posted: Wed Apr 19, 2006 4:07 am Post subject: prop pitch question

Gary,



What is the position of the measurements you have listed below for 

pitch. I'm guessing that the 62 is midpoint on the blade. Correct?



Bruce



Depending on how strong your engine is, I'd see if I could get a custom 

twist

with the twist at 64-62-60.

GrummanDude

Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA

Posted: Wed Apr 19, 2006 10:59 am Post subject: prop pitch question

In a message dated 4/19/06 5:08:00 AM, bruce.smith(at)york.com writes:

 	  Quote: 	
		   64 (first third, near the hub) - 62 (middle) - 60 (tip).

 

 


	


And, I should have said you'll get back about 150 rpm for climb.   



A certain someone I know had one of the new Cheetah Sensenich props pitched 

63-62-61, gained 200 fpm rate of climb AND gained 2 knots.   But, he was able 

to run WAY over redline at 7500 feet.     Now, he can turn redline at 9000 

feet.

_________________
Gary
AuCountry Aviation
Home of Team Grumman

bruce.smith(at)york.com
Guest

Posted: Wed Apr 19, 2006 11:37 am Post subject: prop pitch question

I would imagine that this is in a Cheetah with the HC mod that's been 

further massaged by the folks at Lycon. I wonder what that kind of an 

engine might produce on a dyno...

Bruce

TeamGrumman(at)aol.com said the following on 4/19/2006 2:57 PM:

 	  Quote: 	

 In a message dated 4/19/06 5:08:00 AM, bruce.smith(at)york.com writes:

> 64 (first third, near the hub) - 62 (middle) - 60 (tip).

>     

 And, I should have said you'll get back about 150 rpm for climb.   

 A certain someone I know had one of the new Cheetah Sensenich props pitched 

 63-62-61, gained 200 fpm rate of climb AND gained 2 knots.   But, he was able 

 to run WAY over redline at 7500 feet.     Now, he can turn redline at 9000 

 feet.

GrummanDude

Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA

Posted: Wed Apr 19, 2006 8:38 pm Post subject: prop pitch question

In a message dated 4/19/06 12:37:54 PM, bruce.smith(at)york.com writes:

 	  Quote: 	
		   I would imagine that this is in a Cheetah with the HC mod that's been

 further massaged by the folks at Lycon. I wonder what that kind of an

 engine might produce on a dyno...

 

 Bruce

 


	


actually, no.   This engine has 1500+ SMOH.   77 Cheetah.   Nothing trick on 

this plane except a red rudder cap.   Trues at 132 knots.

_________________
Gary
AuCountry Aviation
Home of Team Grumman

aa1bflyboy(at)msn.com
Guest

Posted: Wed Apr 19, 2006 8:53 pm Post subject: prop pitch question

Has anyone evr done this with a prop for an AA1x model?

Steve Roberts - AA-1B N9664L (at) ILG

In a message dated 4/19/06 5:08:00 AM, bruce.smith(at)york.com writes:

 > 64 (first third, near the hub) - 62 (middle) - 60 (tip).

 >

 >

And, I should have said you'll get back about 150 rpm for climb.

A certain someone I know had one of the new Cheetah Sensenich props pitched

63-62-61, gained 200 fpm rate of climb AND gained 2 knots.   But, he was 

able

to run WAY over redline at 7500 feet.     Now, he can turn redline at 9000

feet.

FLYaDIVE(at)AOL.COM
Guest

Posted: Thu Apr 20, 2006 3:15 am Post subject: prop pitch question

Steve:



ALL PROPS have different pitches at different stations along their length.  

This is not a speed mod or a magic dust trick.



The only trick in picking a pitch is to go has high as you can without 

failing the ground static check.



Barry

"Chop'd Liver"

============================



In a message dated 4/20/06 12:54:23 AM Eastern Daylight Time, 

aa1bflyboy(at)msn.com writes:



 	  Quote: 	
		   

  

  Has anyone evr done this with a prop for an AA1x model?

  

  Steve Roberts - AA-1B N9664L (at) ILG

  

  

  

  

  In a message dated 4/19/06 5:08:00 AM, bruce.smith(at)york.com writes:

  

  

   > 64 (first third, near the hub) - 62 (middle) - 60 (tip).  

  And, I should have said you'll get back about 150 rpm for climb.

  

  A certain someone I know had one of the new Cheetah Sensenich props 

pitched  63-62-61, gained 200 fpm rate of climb AND gained 2 knots.   But, he was 
	


 	  Quote: 	
		    able to run WAY over redline at 7500 feet.     Now, he can turn redline at 

9000
	


 	  Quote: 	
		    feet.

bruce.smith(at)york.com
Guest

Posted: Thu Apr 20, 2006 3:38 am Post subject: prop pitch question

Barry,



I thought this was the case, but had never heard it expressed in this 

manner. It was always that this Tiger has X pitch or this Cessna has Y 

pitch.



Thanks.



Bruce



FLYaDIVE(at)aol.com said the following on 4/20/2006 7:15 AM:

 	  Quote: 	
		   



 Steve:



 ALL PROPS have different pitches at different stations along their length.  

 This is not a speed mod or a magic dust trick.



 The only trick in picking a pitch is to go has high as you can without 

 failing the ground static check.



 Barry

 "Chop'd Liver"

 ============================



 In a message dated 4/20/06 12:54:23 AM Eastern Daylight Time, 

 aa1bflyboy(at)msn.com writes:



   

> 

>  

>  Has anyone evr done this with a prop for an AA1x model?

>  

>  Steve Roberts - AA-1B N9664L (at) ILG

>  

>  

>  

>  

>  In a message dated 4/19/06 5:08:00 AM, bruce.smith(at)york.com writes:

>  

>  

>   > 64 (first third, near the hub) - 62 (middle) - 60 (tip).  

>  And, I should have said you'll get back about 150 rpm for climb.

>  

>  A certain someone I know had one of the new Cheetah Sensenich props 

>     

 pitched  63-62-61, gained 200 fpm rate of climb AND gained 2 knots.   But, he was 

   

>  able to run WAY over redline at 7500 feet.     Now, he can turn redline at 

>     

 9000

   

>  feet.

>

flyv35b(at)ashcreekwirele
Guest

Posted: Thu Apr 20, 2006 5:20 am Post subject: prop pitch question

Yes there are different blade ANGLES specified for a PARTICULAR pitch at 

ever station.  What Gary is saying that these specific angles are deviated 

from to essentially achieve what would be the angle for a 64" pitch at the 

inner third and changing to what would be a 60" pitch angle at the tip. 

This is not common and some prop shops simply won't do it, saying they can 

legally deviate from the specified angles for a particular pitch.



Cliff

---

flyv35b(at)ashcreekwirele
Guest

Posted: Thu Apr 20, 2006 5:56 am Post subject: prop pitch question

Should have said "they can't legally deviated"

---

aa1bflyboy(at)msn.com
Guest

Posted: Thu Apr 20, 2006 8:20 am Post subject: prop pitch question

Yeah that's what I though too..



Do a lot, get a little;

Do a little, get a lot;

Do nothing, get it all.

Steve Roberts - AA-1B N9664L (at) ILG



----Original Message Follows----

From: Bruce Smith <bruce.smith(at)york.com>

Reply-To: teamgrumman-list(at)matronics.com

To: teamgrumman-list(at)matronics.com

Subject: Re: prop pitch question

Date: Thu, 20 Apr 2006 07:37:58 -0400






Barry,



I thought this was the case, but had never heard it expressed in this

manner. It was always that this Tiger has X pitch or this Cessna has Y

pitch.



Thanks.



Bruce



FLYaDIVE(at)aol.com said the following on 4/20/2006 7:15 AM:

 > 

 >

 > Steve:

 >

 > ALL PROPS have different pitches at different stations along their 

length.

 > This is not a speed mod or a magic dust trick.

 >

 > The only trick in picking a pitch is to go has high as you can without

 > failing the ground static check.

 >

 > Barry

 > "Chop'd Liver"

 > ============================

 >

 > In a message dated 4/20/06 12:54:23 AM Eastern Daylight Time,

 > aa1bflyboy(at)msn.com writes:

 >

 >

 >> 

<aa1bflyboy(at)msn.com>

 >>

 >>  Has anyone evr done this with a prop for an AA1x model?

 >>

 >>  Steve Roberts - AA-1B N9664L (at) ILG

 >>

 >>  

 >>

 >>

 >>  In a message dated 4/19/06 5:08:00 AM, bruce.smith(at)york.com writes:

 >>

 >>

 >>   > 64 (first third, near the hub) - 62 (middle) - 60 (tip).

 >>  And, I should have said you'll get back about 150 rpm for climb.

 >>

 >>  A certain someone I know had one of the new Cheetah Sensenich props

 >>

 > pitched  63-62-61, gained 200 fpm rate of climb AND gained 2 knots.   

But, he was

 >

 >>  able to run WAY over redline at 7500 feet.     Now, he can turn redline 

at

 >>

 > 9000

 >

 >>  feet.

 >>

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

GrummanDude

Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA

Posted: Thu Apr 20, 2006 10:16 am Post subject: prop pitch question

In a message dated 4/20/06 4:16:30 AM, FLYaDIVE(at)AOL.COM writes:

 	  Quote: 	
		   ALL PROPS have different pitches at different stations along their length.=A0

 This is not a speed mod or a magic dust trick.


	


true, and not true.



for a 64" pitch, there are specific angles, in degrees, for each station.  

For a 62" pitch likewise.   Making an airfoil that conforms to the different

primary pitches, really changes the way the prop performs.  



It's used in racing at Reno all the time.

_________________
Gary
AuCountry Aviation
Home of Team Grumman

FLYaDIVE(at)aol.com
Guest

Posted: Thu Apr 20, 2006 6:12 pm Post subject: prop pitch question

In a message dated 4/20/06 2:17:10 PM Eastern Daylight Time, 

TeamGrumman(at)aol.com writes:

 	  Quote: 	

  > ALL PROPS have different pitches at different stations along their 

length.> A0

 	  Quote: 	
		    > This is not a speed mod or a magic dust trick.

  >

  >

  true, and not true.

  for a 64" pitch, there are specific angles, in degrees, for each station.  

  For a 62" pitch likewise.   Making an airfoil that conforms to the 

different

 	  Quote: 	
		    primary pitches, really changes the way the prop performs.  

  It's used in racing at Reno all the time.

===============================

So ... Isn't that what I said?

Chop'd Liver rides again!

GrummanDude

Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA

Posted: Thu Apr 20, 2006 9:31 pm Post subject: prop pitch question

In a message dated 4/20/06 7:12:51 PM, FLYaDIVE(at)aol.com writes:



 	  Quote: 	
		   So ... Isn't that what I said?

 

Oh, hell, I guess.   From your understanding of what I said, that is what you 
	


said.   Yes,  "ALL PROPS have different pitches at different stations along 

their length."  I don't think you understand the concept of variable twist 

along the blade as used by racers with fixed pitch props. That is what I was 

talking about.   And that is what Cliff was referring to.   It really isn't worth 

trying to explain.   



Let's just say a stock Cheetah Sensenich prop Model 74DM7S10-1.5-61P (61 inch 

pitch) on a Cheetah that trues at 128 knots (at 5500 feet and 2650 rpm) and 

has trouble pulling over 2700 rpm at 10,000 feet, when given a custom twist 

with an average 62 inch pitch across the blade, GAINED 200 fpm rate of climb at 

an airport at 2000 AGL, Trues at 132 knots (at 5500 feet and 2650 rpm) and can 

still turn 2700 rpm at 10,000 feet, well.....   



Anytime something can be done to increase climb rate, increase true airspeed, 

and not give up horsepower (RPM) at altitude by over loading the prop, I'd 

say that's a magic dust trick.

_________________
Gary
AuCountry Aviation
Home of Team Grumman

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