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Catto Propellers On Certified Super Cubs

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....§ 4a.597 Propellers. Propellers shall be of a type and design which has been certificated as airworthy in accordance with the requirements of Part 14 of this subchapter or shall have been approved as airworthy in accordance with previous regulations, except that wood propellers of a conventional type for use in light airplanes need not be certificated. ....

In this case, it seems to me that "of a conventional type" are the key words.
I wouldn't classify a Catto prop as a conventional wood prop-- would you?
 
In this case, it seems to me that "of a conventional type" are the key words.
I wouldn't classify a Catto prop as a conventional wood prop-- would you?
Not unless you can strip the encasement, apply varnish, go flying and expect to return to where you once departed for many years to come.
 
Conventional? How is it defined? Is it by the blades not changing angle?

Is a constant speed prop with wood blades conventional?
 
In this case, it seems to me that "of a conventional type" are the key words.
I wouldn't classify a Catto prop as a conventional wood prop-- would you?
All of the wood propellers of which I've been involved, have had a fabric covering extending inboard from the tip. Nowhere have I seen anything which defines how far inboard this fabric is allowed to go. Also I seem to recall that Catto used to offer the same prop without the "fabric" covering. Not on their web site anymore. Any definition of "conventional" which we can come up with would need to be confirmed by FAA legal. Do you remember the Flottorp Armor coated props? They were wood with a "plastic" covering over the entire prop.
 
Glenn
he has fallen for Nichol at Catto. I think he spends more time talking and thinking of her
Lately than the rest of us
i know what the cash was for his airplane and mine as well. Sure has made me stop
and look at the fun he is having for a lot less dinero than dad has invested
It's about the best performing Citabria I have been around it's light with a really strong 0320
will he interesting when Nichol takes about 3 airplane units from his checkbook. Of coarse the prop is for my plane since mine is experimental

iim

Hearts are breaking as she just announced her engagement to her long time boyfriend.
 
All of the wood propellers of which I've been involved, have had a fabric covering extending inboard from the tip. Nowhere have I seen anything which defines how far inboard this fabric is allowed to go. Also I seem to recall that Catto used to offer the same prop without the "fabric" covering. Not on their web site anymore. Any definition of "conventional" which we can come up with would need to be confirmed by FAA legal. Do you remember the Flottorp Armor coated props? They were wood with a "plastic" covering over the entire prop.

I wonder what the Aeromatic props have on them?
 
Conventional Design is spelled out in Advisory Circular AC 35-1, pg. 6


Sent from my iPhone using SuperCub.Org
 
Conventional Design is spelled out in Advisory Circular AC 35-1, pg. 6
AC 35-1 12/29/08
j. Fixed pitch wood propellers of conventional design. A propeller that has the following physical properties:
• One piece laminated wood construction
• Two or four blades
• The surface coating does not contribute to the propeller strength
• The surface coating only provides environmental protection
A fixed pitch propeller with a composite shell over a wood core is not a conventional design when the composite shell contributes to the strength and frequency response of the propeller. A fixed pitch wooden propeller with a fabric or composite covering that does not alter the structure for environmental protection is of conventional design.
 
"One piece laminated wood construction"....... ?? I kinda thought laminated was more than one piece by definition, but that's just me.
 
"One piece laminated wood construction"....... ?? I kinda thought laminated was more than one piece by definition, but that's just me.

ya, i had to digest that line a few times too....
I think that they mean once all of the layers are glued together they become one piece. A multi piece prop would be one which the blades attach to a hub or have two or more pieces which can be separated by simple mechanical means.

I don't believe that you will ever find a single piece wood prop which was carved from a single piece of wood without laminating. It would lend itself to warping.
 
Oh I know, and I agree completely. I just couldn't help but point out the oxymoronic qualities in that document. Its so out of character for the FAA....
 
Got this message from Nicole yesterday.
Hey! Saw the thread on SuperCub.org. The rewrite will only cover "simple aircraft" so many two seat aircraft under 250mph. So unfortunately the PA-20/22 and PA-12 won't be covered.
 
The new Part 23 rewrite only applies to "simple aircraft". So any two seat aircraft less than 250mph. Since the PA-12 has three seats it won't fall into the new process of certification. I'd assume once some of the props are certified it would easy to get a field approval for a PA-12.
 
There has been a lot of talk about the construction and composition of our props. The FAA is very confused as well. It's not a "wood" or "composite" prop by definition. Although the prop is over 50% wood by volume it's not considered a "wood" prop reason being the composite is the structure. The wood cannot exist without the carbon and the carbon cannot exist without the wood.
 
The new Part 23 rewrite only applies to "simple aircraft". So any two seat aircraft less than 250mph. Since the PA-12 has three seats it won't fall into the new process of certification. I'd assume once some of the props are certified it would easy to get a field approval for a PA-12.

actually... the PA-12 has ONLY TWO seats... the back seat, just happens to be able to accommodate 2 passengers with using ONLY the ONE lap belt....

I bet that will fly...
 
Fly by night maybe like Mr. Whitekeys when the FSDO is asleep...Days TCDS A-780 lists 3 PCLM and 3 PCSM for Normal category at 1750 and 1838 respectively. But in Utility on standard gear it's a 2 PCLM at 1500.

Don't get pissed. It's in the Book. But sometimes my tri-focals grab the wrong image.

Gary
 
AC 35-1 12/29/08
j. Fixed pitch wood propellers of conventional design. A propeller that has the following physical properties:
• One piece laminated wood construction
• Two or four blades
• The surface coating does not contribute to the propeller strength
• The surface coating only provides environmental protection
A fixed pitch propeller with a composite shell over a wood core is not a conventional design when the composite shell contributes to the strength and frequency response of the propeller. A fixed pitch wooden propeller with a fabric or composite covering that does not alter the structure for environmental protection is of conventional design.

It in the third n forth line. Surface coating that get you.
 
Although the prop is over 50% wood by volume it's not considered a "wood" prop reason being the composite is the structure. The wood cannot exist without the carbon and the carbon cannot exist without the wood.

It in the third n forth line. Surface coating that get you.
Yes until CattoProps provided us with the above statement, we didn't have the definitive answer.
 
I had called the Anchorage Aircraft Certification Office to see if anyone had recorded the webinair they did on props about a month ago. They called yesterday and I was on a conference call with two of the engineers there. Seems that drew at Above Alaska got this whole ball rolling when he wanted to get a Catto prop approved on the Airman raffle Cub. The Super cub is considered a Class I airplane according to the new Part 23 rewrite which means it is a single passenger aircraft. With this rewrite a prop dos not have to have a Type Certificate to be installed on a Class I aircraft as long as it meets the ASTM standards for light Sport aircraft, meets the CAR3 over speed tests and the engine manufacturers rpm ranges and proper prop to ground clearance. There were two expensive tests that were dropped in this Part 23 rewrite. One was the lightning test which probably wouldn't apply to a non-metal prop anyway and the other is the bird strike test. It does have to go through a 50 hour continuous run test and a similar test on a prop with repaired damage. there is also a flight test which can be done in a day. None of this was specific to the Catto prop because they could not speak of any specifics on anything in the works right now but I believe it is safe to say that is what is in the works. It was an educational conversation and I really appreciate them taking the time to get me up to speed on the process. Thought I would pass this information on to the rest of you that might find it as interesting as I did.

Hope to eliminate more of this. :oops:
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Thanks for checking on the Catto progress.
Ya, filing down the prop is not the best weight lose method for a cub.
 
Got this message from Nicole yesterday.

Hey! Saw the thread on SuperCub.org. The rewrite will only cover "simple aircraft" so many two seat aircraft under 250mph. So unfortunately the PA-20/22 and PA-12 won't be covered.

So the PA22/20 colt can be covered. It is only a 2 seater. ?
 
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