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looking for a prop

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erwhites(at)bellsouth.net
Guest

Posted: Thu May 03, 2007 9:34 am Post subject: looking for a prop

I need to replace the prop on my RV4. I have been flying a constant speed up to now, but it has become uneconomic   

to maintain/repair.  I am going to try lighter/simpler for a change, so I’m looking for a wood prop suitable for a 160hp O-320.    

Any recommendations based on actual operational experience would be appreciated.    

Also, if you know of one currently for sale please let me know.  

   

Thanks,  

   

Eric  

erwhites(at)bellsouth.net  

   

     

  2:16 PM

     [quote][b]

ronlee(at)pcisys.net
Guest

Posted: Thu May 03, 2007 10:18 am Post subject: looking for a prop

I had an Aymar Demuth on my O-360 RV-6A.  I  converted to a three blade Catto prop

 and only picked up about 3 mph so either is an  option.

  

 Ron Lee

 [quote]   ---

panamared5(at)brier.net
Guest

Posted: Thu May 03, 2007 11:07 am Post subject: looking for a prop

At 01:17 PM 5/3/07, Ron Lee wrote:

 	  Quote: 	
		  I had an Aymar Demuth on my O-360 RV-6A.  I converted to a three 

blade Catto prop

and only picked up about 3 mph so either is an option.




	


I concur, I fly an Aymar Demuth, he custom builds them to your plane 

and type of flying.  My cruise is very close to Vne.  Cruise is much 

faster than what Van publishes, and climb is still better than Van's specs.



BTW, why is the constant speed uneconomical?  I have never owned one.



Bob

RV6 "Wicked Witch of the West"

gmcjetpilot

Joined: 04 Nov 2006
Posts: 170

Posted: Fri May 04, 2007 1:29 am Post subject: looking for a prop

 	  Quote: 	
		  From: "Eric Whiteside" <erwhites(at)bellsouth.net>

Subject: looking for a prop

  By far the TOP fixed pitch prop choice is the Sensenich.

  There is no faster better performing fixed pitch prop on the marked BAR NONE, and that has been proven by Van.

  You could pop for a new BA hartzell for $5,500 and that is the way to go if you want to stay constant speed.

         Ahhh...imagining that irresistible "new car" smell?

 Check out [url=http://us.rd.yahoo.com/evt=48245/*http://autos.yahoo.com/new_cars.html;_ylc=X3oDMTE1YW1jcXJ2BF9TAzk3MTA3MDc2BHNlYwNtYWlsdGFncwRzbGsDbmV3LWNhcnM-]new cars at Yahoo! Autos.[/url]  [quote][b]

Lukasczyk(at)gmx.net
Guest

Posted: Fri May 04, 2007 3:21 am Post subject: looking for a prop

Hi Eric



Take a look at the MT-170_R185-3E. It is a fixed pitch wooden prop with stainless steel protected leading edges. It is also covered by fiberglass. 

I think it is perfectly pitched for a RV-4 powered by an O-320 (160hp). I am reading exactly 2700rpm at full throttle and top speed.



http://www.rv-4.de/



Thomas, rv-4 0-320

-- 

"Feel free" - 10 GB Mailbox, 100 FreeSMS/Monat ...

Jetzt GMX TopMail testen: http://www.gmx.net/de/go/topmail

steve(at)newtech.com
Guest

Posted: Fri May 04, 2007 4:20 am Post subject: looking for a prop

gmcjetpilot(at)yahoo.com wrote:

 	  Quote: 	
		   >From: "Eric Whiteside" <erwhites(at)bellsouth.net>

 >Subject: looking for a prop

 By far the TOP fixed pitch prop choice is the Sensenich.

 There is no faster better performing fixed pitch prop on the marked 

 BAR NONE, and that has been proven by Van.

 You could pop for a new BA hartzell for $5,500 and that is the way to 

 go if you want to stay constant speed.

Dive for the foxholes, I can already hear all of the Catto owners 

pounding on their keyboards.  Stay tuned.  I have a 3 blade catto on 

order for my RV-7A project, but, it will not be flying until early next 

year.  As soon as it arrives, my hangar mate is going to mount it on his 

RV-7 for comparison testing against his fixed pitch Sensenich.  Just 

wait for the documented scientific experiment.  I know there will be 

some replies that comment on how prop efficiency goes down as the number 

of blades increase; the testing will give us the answers.

Steve Eberhart

RV-7A - On it's gear and O-360-A1A mounted

do not archive

panamared5(at)brier.net
Guest

Posted: Fri May 04, 2007 5:11 am Post subject: looking for a prop

 	  Quote: 	
		  By far the TOP fixed pitch prop choice is the Sensenich.



There is no faster better performing fixed pitch prop on the marked 

BAR NONE, and that has been proven by Van.




	


And how do we know this?



Where I can I find the raw data or the source information?

How about a list of all the props used in the comparison evaluation?

Was standard off the self props used, or did the tester test all 

variations of a prop from all manufacturers?

Did the tester test custom built props?

Was the exact same pilot, plane, altitude, weather used to evaluate 

all the different props?

Was all the testing on the same day?

If not, what errors were induced by different days?

Did all the fuel used come from the same fuel batch?

What sort of instrumentation was used to evaluate the prop?

What were the props evaluated for?  Speed, efficiency, climb, 

smoothness, vibration, weight etc?

What  testing methodology was used?

Who did the data analysis?

How confident was the tester in the final result based upon the data analysis?



Bob

RV6 "Wicked Witch of the West"

Bob Collins

Joined: 11 Mar 2006
Posts: 470
Location: St. Paul, Minnesota

Posted: Fri May 04, 2007 5:27 am Post subject: looking for a prop

Information that may be of interest to folks in this discussion about props.

Using the handy, dandy Rvator index,

( http://rvhotline.expercraft.com/articles/2006/rvator_index.html ), I found

two articles that folks may want

To read.



2003 Issue 5, page 3  "The best damn prop west of the Pecos: How much of a

difference is there really?" (Van)

2004 Issue 1  page 4  "More on Props" (Van)

2002 Issue 5, page 14 "Behind the Scenes: There's more to matching engines

and props than you might think" (Ken Scott, I presume)



I don't know if all the answers people are seeking are in these articles --

probably not. But they might provide some points of reference.



You know, in that last issue, there was a good article on the canopy frame

that I'd forgotten all about until I used the index and searched on a lark.



Bob

 



--

_________________
Bob Collins
St. Paul, Minn.
Letters from Flyover Country
http://rvnewsletter.blogspot.com/

klwerner(at)comcast.net
Guest

Posted: Fri May 04, 2007 6:52 am Post subject: looking for a prop

Really,  I would prefer a Catto  Composite (2 or 3 blade) over that heavy sucker any day!  That would  be "MY" best choice in a FP Prop!

  

 But I do agree that the blended  airfoil Hartzell is probably the best constant speed choice.   do not  archive

 [quote]   ---

lors01(at)msn.com
Guest

Posted: Fri May 04, 2007 7:03 am Post subject: looking for a prop

<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->  Music to my ears Ron.   There is usually a speed penalty for  going to 3 blades from 2.  Catto must do a really fine job to give any  increase at all.  Any RPM difference in this swap?

  

 Tracy Crook  (Catto 3 blade on 20B powered RV-

 [quote]   ---

ronlee(at)pcisys.net
Guest

Posted: Fri May 04, 2007 8:39 am Post subject: looking for a prop

Tracy, I got right at 2700 RPM at full throttle at 8000'  DA with the Aymar Demuth.

 I have yet to check the RPM under similar conditions with  the Catto prop.  If my

 recollection is right the speed delta was at 11,500' DA  since it was too time consuming

 to fly southeast to get to lower altitude.

  

 Ron Lee

 [quote]   ---

gmcjetpilot

Joined: 04 Nov 2006
Posts: 170

Posted: Sat May 05, 2007 2:21 am Post subject: looking for a prop

 	  Quote: 	
		  From: "Eric Whiteside" <erwhites(at)bellsouth.net (erwhites(at)bellsouth.net)>

 Dive for the foxholes

   
	


  ha ha funny you are right see.....

   

   

  >>From: Bob <panamared5(at)brier.net (panamared5(at)brier.net)>

 	  Quote: 	
		  >

  >>Where I can I find the raw data or the source information?
	


 	  Quote: 	
		  >How about a list of all the props used in comparison evaluation?

>blaaa blaaa blaaa blaaa blaaa blaaa

   
	


   

  Bob I usually don't respond to some one that's sporting what 

seems to be an chip or attitude. How about you tell me what 

prop turns you on and I say GREAT and tell you what you 

want to hear, its the best.

   

  If you want the truth Van (Richard Vangrusven) did the test. I 

have been involved in RV's for +20 years and I can tell you his  

test abilities are scientific and meaningful. The test results where 

published in the RVator. Because I like you I scanned it and its 

here:

   

  http://img82.imageshack.us/my.php?image=prop200415me.jpg

  (might have to click to make full size)

   

   

  Now of course this is the Sensenich against all constant speed 

props and at one "cruise condition". Lets just say the Hartzell 

BA (blended airfoil) prop is the best of the best and also like the 

Sensenich, designed, engineered and test specifically for the RV, 

unlike generic props that are made for the RV market. 

   

  The Sensenich was almost as fast as the Hartzell in this test and 

faster than many of the other constant speed props. 

   

  Note you can debate and whine about how this test did not  test 

XYZ condition or ABC condition, but I don't care. This is a 

significant test that is meaningful and gives a good bench mark 

and is consistent with theoretical predictions and results others 

have seen. I did flight test for a living and now fly large jets; I 

know what I am talking about, and I am not going to argue with 

you. Believe what you want. I can tell by your post you know 

everything.)

   

   

   

  Before you lecture me, the Professor, I have a masters in 

Aeronautical engineering and fly big jets so I am smarter than 

you. (ha ha ha ha). Seriously let me spell it out two truths:

   

  1) Metal bladed props are thinner and more efficient than any 

wood bladed or wood / fiberglass prop. Fact 

   

  2) Three bladed props are slower than two bladed in the horse 

power and speed range RV's run in. When you get  into 600 HP 

and 250 kts you might have an advantage with three blades. Fact

   

  

Catto makes a nice prop but its not the fastest, sorry. They 

are well made and only heard of one break apart, spit a blade 

clean off. That was on Reno racer. There are advantages of 

wood like lower weight and less vibration. 

   

   

  Now the soft advantage of Sensenich is its a BIG company that 

has been in business like 80 years and made a prop specifically 

for RV's. I think their engineering and testing is probably better 

than say Catto, a guy carving props out in his shop, no offense. 

Keep in mind when we talk 4 or 6 mph it may be only  2% or 3%

difference in performance.



   

  Cost? Sensenich with all the hardware is  $2000. 

What does a Catto cost? $3000 with out hardware? 

   

  Nuff said, but I would beg guys to not  be blinded by the sexy look 

of a painted three blade wood prop over a boring grey two blade 

Sensenich, which although is boring to look at on the ground is 

technically superior. Last Catto guys (guys flying Catto or other 

props)  who don't lie estimate they are about 4-7 mph slower than 

the Sensenich. 

   

  The problem with testing props is there are so side by side prop  

test.  Swapping props out on the same plane is a pain. Ideally you 

would get two similar planes and fly them side by side and than 

swap props. Because of this hassle there is a lack of information 

and data. The prop makers don't want to do it. They would rather 

float a myth that theirs is the best. This opens the field to tall tails, 

unsupportable claims and really bad flight test data. When so called 

test are done sometimes like a MT prop dealer Lessdrag in CA,  

who although is well meaning, has no clue and  ends up with results 

that are clearly garbage. That does not apply to Van who has an 

impeccable reputation for accurate and repeatable test data. 



   

   

  However despite the lack of test data I know the math and prop 

theory , the basics. Just on paper the Sensenich is faster than 

other fixed props. Look at the above data, the slowest is a wood-

fiberglass MT three blade prop. That is NOT an accident. One  

reason is as I mentioned above, I'll repeat:



   

   

  *****

  Wood props are thicker than metal and therefore wood props are 

less efficient (slower). This effect is not as prevalent on slow planes 

or in climbs (slow speed).

   

  The Sensenich was DESIGNED specifically for the RV and was 

tested by professional prop designers, engineers and technicians



  *****

   

  You  can flame me, that is fine. If you just want to believe your 

prop or the one you want to buy is the the best in the world and 

will not consider the info I presented, I'm OK with that, but don't 

waste your time flaming me; I don't care and you are clearly 

smarter than I am. And if your buddy is going lickity split in 

his RV with a Catto (turning 2,950 rpm) than great. BTW 

Lycoming says your engine should be torn down if you turn 

higher than 2,970 RPM. Don't shoot the messenger, Lycoming 

service bulletin. Even rpm over 2835 rpm is serious and requires 

major repeated inspections. Yes, you will go faster if you over 

rev your engine, but RPM for RPM the Sensenich is more efficient 

with its thinner blades.



   

  PROP for PROP the Sensenich is the best performing and BEST 

value of any fixed prop available for the RV, period. Now weight 

and looks is another factor. I also like the  feel of a fixed wood prop, 

but a well balanced metal prop on a balanced engine is plenty 

smooth if properly installed and balanced. No offense to Catto 

or MT or other wood bladed props, but there are compromises 

in life and no free lunch.

   

  Bob, don't be offended I am only raging on you because of your 

  20 questions you demanded answers for.

  

Sincerely the Professor, 

  George ATP/CFI-II-ME, RV-7/RV--4/B757



         Ahhh...imagining that irresistible "new car" smell?

 Check out [url=http://us.rd.yahoo.com/evt=48245/*http://autos.yahoo.com/new_cars.html;_ylc=X3oDMTE1YW1jcXJ2BF9TAzk3MTA3MDc2BHNlYwNtYWlsdGFncwRzbGsDbmV3LWNhcnM-]new cars at Yahoo! Autos.[/url]  [quote][b]

steve(at)newtech.com
Guest

Posted: Sat May 05, 2007 3:39 am Post subject: looking for a prop

gmcjetpilot(at)yahoo.com wrote:

[snip]

 	  Quote: 	
		   Cost? Sensenich with all the hardware is  $2000.

 What does a Catto cost? $3000 with out hardware?

Really hate to detract from a good professional rant by bringing facts 
	


to the table, but, just to keep the record straight here is my invoice:

Invoice

  Catto Propellers

  15301 Jesus Maria Rd.

  Mokelumne Hill, CA  95245

  209-754-3553



+-----------------------------------+

|     DATE      |     INVOICE #     |

+-----------------------------------+

|    2/11/07    |        826        |

+-----------------------------------+



     +-------------------------------------------------------------------+

     |             BILL TO             |             SHIP TO             |

     +-------------------------------------------------------------------+

     |         xxxxxxxxxxxxxx          |                                 |

     |      xxxxxxxxxxxxxxxxxxxx       |                                 |

     |      xxxxxxxxxxxxxxxxxxxx       |             Same                |

     |          xxxxxxxxxxxx           |                                 |

     |        xxxxxxxxxxxxxxxxx        |                                 |

     +-------------------------------------------------------------------+



+---------------+

|   DUE DATE    |

+---------------+

|    6/4/07     |

+---------------+



+----------------------------------------------------------------------------+

|     ITEM     |           DESCRIPTION           |  QTY  |  RATE  |  

AMOUNT  |

+----------------------------------------------------------------------------+

|3-Bladed      |3-Bladed Wood/Glass Composite    |    1.0|1,850.00|  

1,850.00|

|              |Propeller for RV-7A              |       |        

|          |

|              |66" Diameter x 76" Pitch         |       |        

|          |

|              |0-360  180HP(at)2700RPM             |       |        

|          |

|              |Top Speed at Target RPM-         |       |        

|          |

|              |205mph(at)2800rpm                   |       |        

|          |

|              |4.375" Finished Propeller        |       |        

|          |

|              |Thickness                        |       |        

|          |

|              |7" Diameter Prop Flange          |       |        

|          |

|              |SAE-2 Pattern,  1/2" Bolts and   |       |        

|          |

|              |3/4" Lugs                        |       |        

|          |

|              |Color White with Customer        |       |        

|          |

|              |supplied tip color..   Crescent  |       |        

|          |

|              |Tips                             |       |        

|          |

|              |                                 |       |        

|          |

|Shipping      |Shipping Charges                 |    1.0|   65.00|     

65.00|

|Labor         |Fitting of Customers Spinner     |    1.0|  110.00|    

110.00|

|              |Kit, cutouts, tracking and       |       |        

|          |

|              |drilling of mounting holes.      |       |        

|          |

|              |Call customer to when to ship    |       |        

|          |

|              |Spinner Kit.                     |       |        

|          |

+----------------------------------------------------------------------------+

|7.25% Tax     |                                 |                       

0.00|

|Subtotal      |                                 |                   

2,025.00|

|              |                                 

+---------------------------+

|Total         |                                 |                   

2,025.00|

+----------------------------------------------------------------------------+



Steve Eberhart

RV-7A, on it's gear with engine mounted

DO NOT ARCHIVE

gcomfo(at)tc3net.com
Guest

Posted: Sun May 06, 2007 10:26 am Post subject: looking for a prop

[quote]   

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