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Last of the Aeromatic Props - Advice Needed

GottaAV8

Registered User
Hi all,

I need some sage advice from the Cub Gods.

I have a PA-12 with an O-235-C1. I acquired what I believe is the last certified Aeromatic prop ever produced. The problem is that the prop has a type 1 flange, and my 235 has a type 2 flange.

Looking for a way to get the prop (legally) on my plane. Any ideas?

Is it even worth it?

Thanks!
 
There is a retired airline pilot out in the pacific northwest that has the type certificate rights and repairs and makes new
blades for the Aeromatic prop. can't think of his name now but someone on this site will probably respond. If not, I can probably find it !!!
 
Hi all,

I need some sage advice from the Cub Gods.

I have a PA-12 with an O-235-C1. I acquired what I believe is the last certified Aeromatic prop ever produced. The problem is that the prop has a type 1 flange, and my 235 has a type 2 flange.

Looking for a way to get the prop (legally) on my plane. Any ideas?

Is it even worth it?

Thanks!

Is this prop approved on the airframe? Is it called out on the Type Certificate? If not, good luck getting it approved.

Why do you want to install this prop?

MTV
 
thanks everyone for their posts!

To answer the questions:

1. jcrowles - Are you thinking of Tarver LLC near Reno? I bought this prop from Tarver about a week before they lost their ability to make/service certified props. It's beautiful, has new blades, but shipped with the wrong flange and there's nothing Tarver can do to help me now. It's a darn shame, and I have lots of respect for Tarver, but this isn't really about them. I now have a prop with a type 1 flange and I need to find a way to bolt only my type 2 flange.

2. mvivion - The prop is on the type certificate for the PA-12, and may be paired with a O-235-C1 engine. I bought it primarily because of the substantial improvement in take-off performance. I also liked the fact that it kept my stock PA-12 stock.

3. n40ff - If this doesn't work, I'll be taking up a collection for a new O-320 (or maybe a O-290-D2). I didn't go that way for a couple of reasons. Money, weight, and I really only wanted to improve climb performance. I'm very happy with my cruise performance and fuel burn. The Aeromatic looked like a good idea. I know you don't get something for nothing though.


I could try to get a prop extension/converter made (by Saber) and try to get a 337 approval? I could simply drill Type 2 holes in the aeromatic plate, but I don't know how to do that legally? Can a DAR help me?

Any other ideas?
 
Find someone with a type 2 hub. Hubs are out there, it is good blades that are hard to find. Kent probably has serviceable hubs.
 
Hi Skywagon. Sorry I left you off my reply... unintentional.

Check out the latest news on that link. They're out of buisiness. That's my problem :-(

I see from previous posts that you're pretty familiar with Aeromatic. Any advice would be greatly appreciated.
 
thanks Steve,

I agree that the blades are hard to come by, and I'm lucky to have new ones. I can certainly get a Type 2 hub from Tarver, but I'm told that there isn't anyone who has a repair station for Aeromatics. (there also isn't anybody who has the manufacturing rights for the blades either).

know of someone who can swap hubs?

jeff
 
Hi Skywagon. Sorry I left you off my reply... unintentional.

Check out the latest news on that link. They're out of buisiness. That's my problem :-(

I see from previous posts that you're pretty familiar with Aeromatic. Any advice would be greatly appreciated.

See if Tarver can swap your hub with the correct one. I don't believe you need a repair station to do that.
Talk to Kent or Glenn. They are good people. I'm sure that they will try to help you find a way to solve your dilemma. I saw that note on their web site and do not know the reason for it.

Generally a "repair station" is restricted to specific functions on specific items. However a person with a "propeller repairman's" certificate may be able to work on any propeller. Again, talk to them about replacing the hub.
 
thanks Steve. I spent about a year working with Tarver, trying to get the hubs swapped. They can't do it legally and issue the new paperwork. I've never considered having them/someone do it under a 337 form though? I can certainly get a hub. I'll call Tarver again and ask.

If that doesn't work, I'm back to the beginning of this thread :)
 
The new requirements for a repair station and the associated paperwork are unbelievable. You practically have to have a full time employee to deal with it. I am sure Tarver told them to stick it. If someone brought me an Aeromatic prop to install I believe I could look at it and make a determination to it's airworthiness. I have seen plenty of log book entries of mechanics installing an "Owner Provided Part".
 
you nailed it, Steve. The requirements are excessive, and have drummed a lot of really good, and dedicated people, out of the business... but that's a different fight.

I would happily fly from VA to TX with a McCauley on the front and an Aeromatic in the back if you could help me fly from TX to VA with an Aeromatic on the front and a McCauley in the back ;-)

jeff
 
I don't see any problem installing the Aeromatic prop on your plane. The problem that I see is that an A&P mechanic is not allowed to dismantle and reassemble the prop in order to change the hub. At least this used to be so, unless something has changed of which I am not aware.

There is an adapter plate/spacer for installing certain metal props on the 0-235 with different flanges. Perhaps if you could find one of these adapters the solution would be relatively easy?
 
Thanks Skywagon. I agree. I don't think anybody can legally replace the hub right now.

What I have is a perfectly legal, beautiful, aeromatic prop with a type 1 flange. The Reno FSDO has been all over the paperwork and dataplate, and they're good. I don't want to do anything to ruin that.

I would really love to put a prop extension/adapter on it and have an A&P bless it (as Mr. Pierce described). This adapter will need to be a non-certified, "Owner provided" adapter as far as I can tell. McCauley had made a Type1 to Type 2 adapter for their Met-L props... I have one on my PA-12 right now (it's what caused me to measure/order the wrong flange in the first place!) it cannot be used with the aeromatic because the center "boss" is too big. it goes over the existing flange boss, and it cannot be machined down because there is not enough metal.

I could have Saber make one for me if I could get it signed off. They make nice stuff.

I'm also told that there are other flanges out there? Someone mentioned that a Diamond DA-40 has an prop adapter? I have no idea.


Thanks again,

jeff
 
Would this work? The Aeromatic props are type certificated. They were certified under the Civil Aircraft regulations. I could not find in the CARs where a prop needed a repair station for a minor alteration. Changing one approved part for another approved part is a minor alteration , is it not? Any mechanic can change the hubs, can he not? There is no machining or special tools involved? Just changing one approved part for another airworthy approved part. Why would it need a repair station? It's not getting an overhaul or the blades reprofiled. jrh
 
Would this work? The Aeromatic props are type certificated. They were certified under the Civil Aircraft regulations. I could not find in the CARs where a prop needed a repair station for a minor alteration. Changing one approved part for another approved part is a minor alteration , is it not? Any mechanic can change the hubs, can he not? There is no machining or special tools involved? Just changing one approved part for another airworthy approved part. Why would it need a repair station? It's not getting an overhaul or the blades reprofiled. jrh

I dunno... it's a good question. Is changing the hub a major or minor alteration? I think that the hub contains shims, etc. that require great care to properly set up if you change the blades. I'm pretty sure that a good mechanic could figure it out if he had the manual in front of him. I'm guessing that the FAA would say that you need to be a repair station to work on the hub.

Any prop experts out there that can help?
 
Read FAR 43, appendix A, (a), (3) propeller major alterations. A hub change is a minor in accordance with these specs. You are not changing the hub design and you are not installing parts not approved for this prop. Swap the hub and sign it of in the log book.

Web
 
Would this work? The Aeromatic props are type certificated. They were certified under the Civil Aircraft regulations. I could not find in the CARs where a prop needed a repair station for a minor alteration. Changing one approved part for another approved part is a minor alteration , is it not? Any mechanic can change the hubs, can he not? There is no machining or special tools involved? Just changing one approved part for another airworthy approved part. Why would it need a repair station? It's not getting an overhaul or the blades reprofiled. jrh

I dunno... it's a good question. Is changing the hub a major or minor alteration? I think that the hub contains shims, etc. that require great care to properly set up if you change the blades. I'm pretty sure that a good mechanic could figure it out if he had the manual in front of him. I'm guessing that the FAA would say that you need to be a repair station to work on the hub.

Any prop experts out there that can help?
An A&P Mechanic is not allowed to do very much at all to propellers other than minor dressing of nicks and refinishing. A propeller repair station can do what you need IF they have the proper manuals. An old prop shop may have the manuals on the shelf in which case you are golden. Start calling different prop shops and ask some questions. I'm sure that the Tarvers will help you with the proper hub if they have one.
 
..I would really love to put a prop extension/adapter on it and have an A&P bless it (as Mr. Pierce described). This adapter will need to be a non-certified, "Owner provided" adapter as far as I can tell. McCauley had made a Type1 to Type 2 adapter for their Met-L props... I have one on my PA-12 right now (it's what caused me to measure/order the wrong flange in the first place!) it cannot be used with the aeromatic because the center "boss" is too big. it goes over the existing flange boss, and it cannot be machined down because there is not enough metal.

I could have Saber make one for me if I could get it signed off. They make nice stuff.

I'm also told that there are other flanges out there? Someone mentioned that a Diamond DA-40 has an prop adapter? I have no idea.


Thanks again,

jeff
The problem with "owner provided" is that it still needs to be made in accordance with an approved drawing or direct copy of an approved part. You can't just cobble up a homemade adapter and be legal. Unless you can get your local FSDO guy to give you a field approval for your home-brew adapter. With a little research this may be possible.

I don't know about the DA-40 adapter but it may just be a spacer to push the prop further from the crank flange.
 
I dunno... it's a good question. Is changing the hub a major or minor alteration? I think that the hub contains shims, etc. that require great care to properly set up if you change the blades. I'm pretty sure that a good mechanic could figure it out if he had the manual in front of him. I'm guessing that the FAA would say that you need to be a repair station to work on the hub.

Any prop experts out there that can help?

Hello GottaAV8,

Do you still have that Aeromatic with the Type I hub? I can get you an Aeromatic with a Type II hub that came off a O-235 powered Piper. Can I get your Aeromatic with the Type I hub for my Continential powered Cub? I have been searching high and low for an Aeromatic for my C-85 powered J3.
 
I was considering a Hartzelite ( ground adjustable) and had found one with good blades and the wrong hub. I had the correct hub with no blades.
Talking with my PMI he suggested a propshop, H&S Propeller in White Lake, MI, that had approvals for all propellers. They said they could do it, but the price for everything got to high so I dropped the project.



Dave
 
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