VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Model Specific > RV-12/RV-12iS
Register FAQ Members List Calendar Today's Posts

Reply
 
Thread Tools Search this Thread Display Modes
  #31  
Old 11-25-2011, 03:48 PM
rvbuilder2002's Avatar
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
Default

Quote:
Originally Posted by DonFromTX View Post
I would bet you have not a single Viking powered aircraft incident, nor any propellor statistics from this maker.
Don,
I think Darwins point is, that because there is only a few Viking engines flying, and no to very little reliability data available on the propeller, equipping a new airplane with both would be configuring a new airplane so that it was operating at the fringe edge of "Experimental" (in the amateur built category anyway),and all of the additional risks that go with that.

I would say that I agree.

You are right. The experimental category is all about experimenting. But often people are a bit naive as they cross into a much riskier part of it ( I am not directing that comment at you specifically Don, just speaking of the home building community in general). I think it is important for those of us that have long term experience, pass along the gained wisdom to others.

In this case I would say the message is... "Just because a company has a nice looking web site and is willing to take your order", doesn't mean it is a proven or safe product. As long as someone goes in with eyes wide open, and is aware of the risks and realizes that they are actually doing testing for the manufacturer(s), I say go for it.

The problem is that very few people who purchase the next new promising ___________ (fill in the blank) are aware of that, even though I would bet that the majority of the people that participate in this forum have no desire to knowingly put them self in that position.
Reply With Quote
  #32  
Old 11-25-2011, 06:54 PM
DonFromTX's Avatar
DonFromTX DonFromTX is offline
 
Join Date: Oct 2010
Location: La Feria Texas
Posts: 3,822
Default

This attack was in response to my comment of having paved the way for an engine developer to try it out to see if it was really snake oil, nothng about my trying one out.
I am sure you would agree that if everytime someone mentioned the Rotax/Sensenich combo, there was a string of stuff about broken crankshafts, engine mounting bolts falling out, Bing floats sinking, gascolator overheating, sprag clutches failing, fuel pumps failing, and even the Sensenich prop hubs machined wrong, and the fuel tank spraying you with gasoline in a hard landing, it would simply not be productive. Look at the pile of AD's on certified planes for example. Lets just get along, have a positive look at problems and look for solutions, is that asking too much?
__________________
A&P, PP-SEL, Pathological Flier, EAA Technical Counselor
EAA Chapter 595 President,http://www.595.eaachapter.org/index.htm
Retired US Army Officer
Reply With Quote
  #33  
Old 11-26-2011, 05:42 AM
BigJohn BigJohn is offline
 
Join Date: Nov 2008
Location: Gloversville, NY
Posts: 1,587
Default In the spirit of a gentlemanly discourse..................

Ok boys, let's see if we can keep this discusion objective, and not let it get so personal that it gets shut off! I would like to make a point based on many years in the computer software development business.

If you can possibly avoid it, never make more than one change at a time. Because, if something doesn't work just right, you won't be able to tell which change is causing the problem. I believe that principle applies in this case. Nothing against experimentation, or this particular engine or propellor. It's just that I would want to see some time put on one new system, before introducing another into the mix. No matter what the application.
__________________
John Peck, CFII, A&P, EAA Tech Counselor, Flight Advisor.
?Master Pilot? Award, UFO Member.
RV-12 N37JP 120176 Flying since 2012.
One Week Wonder Build Team, OSH 2018.
VAF paid through 10/2019.
Reply With Quote
  #34  
Old 11-26-2011, 05:43 AM
woodmanrog's Avatar
woodmanrog woodmanrog is offline
 
Join Date: May 2005
Location: Florida
Posts: 774
Default

In reading this forum, I see a lot of bickering and arguing about new design and how it may apply to what we use now. I only saw one response that referred to asking real experts (prop manufacturers) what they thought of a new design. If no one tried something new, Craig Catto would never have developed one of the best products on the market. (My opinion) Wouldn't you think he may have experimented with the same type of design after reading or seeing it and redesigning his own props if there was a distinct advantage? Anyway as far as engineering is concerned, remember that the Titanic was designed by "Expert engineers". LOL
Reply With Quote
  #35  
Old 11-26-2011, 06:56 AM
AlanTN AlanTN is offline
 
Join Date: Apr 2011
Location: Linden, TN
Posts: 79
Default Pilot Error!

And the Titanic went down because of pilot error, not faulty design! Knowing the ice field was there they should have diverted south. They should also have reduced speed. They did neither because they were in such a hurry to get to New York. Lessons for us.
Reply With Quote
  #36  
Old 11-26-2011, 10:00 AM
E. D. Eliot E. D. Eliot is offline
 
Join Date: Dec 2005
Location: San Pedro
Posts: 1,013
Default Cato three blade prop

If I had a finished and flying 12, I'd be begging Mr. Craig Catto to produce a 3 blade prop for me. It's purely subjective but I really like to look of a three blade prop - nothing complicated here. Hope that there will be a Catto 3 blade available by the time that my 12 is completed - also hope that Van's will be offering it as part of the finishing kit. Dream on???
Reply With Quote
  #37  
Old 11-26-2011, 10:28 AM
DonFromTX's Avatar
DonFromTX DonFromTX is offline
 
Join Date: Oct 2010
Location: La Feria Texas
Posts: 3,822
Default

For reasons I don't profess to fully uderstand, two bladed props and PSRU do not get along well at all. Think of all the gear reduction units, most have had more than 2 blades. The RV12 is somewhat of an exception. The Viking for instance does not recommend using a two blade because of this. The one at Oshkosh this year that flew up with a two blade prop has now changed to a 3 blade. Might be somethig for Vans to investigate further, and certainly something for thinkng owners to try out. I too think they look cool!

Quote:
Originally Posted by E. D. Eliot View Post
If I had a finished and flying 12, I'd be begging Mr. Craig Catto to produce a 3 blade prop for me. It's purely subjective but I really like to look of a three blade prop - nothing complicated here. Hope that there will be a Catto 3 blade available by the time that my 12 is completed - also hope that Van's will be offering it as part of the finishing kit. Dream on???
__________________
A&P, PP-SEL, Pathological Flier, EAA Technical Counselor
EAA Chapter 595 President,http://www.595.eaachapter.org/index.htm
Retired US Army Officer
Reply With Quote
  #38  
Old 11-26-2011, 10:48 AM
Tony_T's Avatar
Tony_T Tony_T is offline
 
Join Date: Dec 2008
Location: Lacey, WA
Posts: 1,365
Default Seen before...

...in a previous post. Good looking Sensenich 3-blade mounted up on a 12.



An update on this installation regarding performance would be interesting.

Tony
__________________
Tony
E-LSA RV-12 ULS
Reply With Quote
  #39  
Old 11-26-2011, 10:54 AM
n5lp's Avatar
n5lp n5lp is offline
fugio ergo sum
 
Join Date: Apr 2006
Location: Carlsbad, NM
Posts: 1,912
Default

Quote:
Originally Posted by AlanTN View Post
And the Titanic went down because of pilot error, not faulty design! Knowing the ice field was there they should have diverted south. They should also have reduced speed. They did neither because they were in such a hurry to get to New York. Lessons for us.
Just as in many airplane accidents there were several things that contributed to the sinking. It appears that there were questionable decisions by the captain but that is not enough to account for the severity of the accident. There is a very interesting modern analysis available.

http://www.writing.eng.vt.edu/uer/bassett.html

The Rivets. The wrought iron rivets that fastened the hull plates to the Titanic's main structure also failed because of brittle fracture from the high impact loading of the collision with the iceberg and the low temperature water on the night of the disaster. Figure 2 shows the Titanic during her construction, with the riveted hull plates of her stern visible. With the ship travelling at nearly 25 mph, the contact with the iceberg was probably a series of impacts that caused the rivets to fail either in shear or by elongation [Garzke and others, 1994]. As the iceberg scraped along sections of the Titanic's hull, the rivets were sheared off, which opened up riveted seams. Also, because of the tremendous forces created on impact with the iceberg, the rivet heads in the areas of contact were simply popped off, which caused more seams to open up. Normally, the rivets would have deformed before failing because of their ductility, but with water temperatures below freezing, the rivets had become extremely brittle.

A lot of this is very familiar to those who read aircraft accident reports. A chain of events, conditions and a lack of materials and construction understanding were all important.
__________________
Larry Pardue
Carlsbad, NM

RV-6 N441LP Flying
Reply With Quote
  #40  
Old 11-26-2011, 10:55 AM
Snowflake's Avatar
Snowflake Snowflake is offline
 
Join Date: Oct 2009
Location: Victoria, BC, Canada
Posts: 3,932
Default

"FSTexan - Join Date: Nov 2011 - Location: x - Posts: 1"

Please consider the source when someone revises a dead thread with inflammatory info... Please do not feed the trolls.
__________________
Rob Prior
1996 RV-6 "Tweety" C-FRBP (formerly N196RV)
Reply With Quote
Reply



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 06:46 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.