Prop Bolts

[gellisor]

Having trouble finding the torque specifications for a wood prop on a 7ac 65 hp. What are they and are they the same for all brands of wood props? Thanks for help & suggestions.

[Guest]

If you have a Sensenich wood prop you can go to www.sensenich.com and they have a pdf download with torque specs for your particular application. Hope this helps......

Mike Berg

[Tim Juhl]

I assume you have the metal crush plate that goes on the front of the prop and are not inserting the bolts directly in the prop hub. I wouldn't even ask except there was a guy around here that didn't know one was needed and did a real number on his prop. Bolts are typically torqued to 200 inch-pounds. The Sensenich website also has some good downloadable pdf's on proper prop care and installation advice. One thing many wood prop users are unaware of is the fact that wood props should periodically be re-torqued. I live in Michigan and re-torque in winter and summer.

Tim

[gellisor]

Yep, the metal face plate is there. New hup, prop and all, looks proper. The prop is made by Falcon. I could not find a web site regarding their product. I viewed the Sensenich site and it has good info; however, I am unsure about the bolt size and if all wood props would be considered the same. Believe the bolts are 3/8"? I know Sensenich is the recommended manufacturer. Anyone with experience with Falcon? Was told that it is approved for the 7ac.

Thanks.

[gusc]

gell,

I sure would check the Type Data Sheets and with the Falcon manufacturer before I used a prop based on what someone said. I never heard of a Falcon prop but that doesn't mean it is not ok. It sounds like a prop for homebuilts to me?

Search the internet for Falcon information. Surely you got some paperwork with the prop? What did your A & P write in the logbook?

[gellisor]

Here is the deal on the Falcon Propellers. They are a small manufacturer located at Route 1, Box 262, Washington, Ok. 73093. Phone (405) 288-6778. The prop was manufactured in accordance with FAA approved design data and airworthiness. It was signed of by the FAA and all logs, paperwork, and installation is proper. They make 1-2 props a week. It is a beautiful prop and good performance. I recently bought the Champ and the prop was on the plane. A picture of which is on page 70 of the June issue of PrivatePilot. It is the red & white Champ.

I did not look hard enough at my paperwork and was tring to get public information about Falcon; of which there is very, very little. All's well, ends well.

[Guest]

Falcon Wooden Propellers (formerly Fahlin) www.modernwoodenpropellers.com/fahlin.htm
Also see Watson Propellers

[visitor]

A propeller may have FAA design & manufacturing approval, but is it approved for "that" airplane?

For a propeller to be legal to install on a US type certificated airplane one of the following must exist:

1. Listed in the airplane TCDS.
2. STC'd for the airplane. (337 form)
3. Field Approval for Make, Model & Serial Number of airplane. (337 form)

Because an airplane has had the prop on it for the last 10 years & has been signed off as airworthy by numerous IA's every year does not mean that the prop is legal for "that" airplane.

I've seen airplanes that had un-approved parts installed on them and had been signed off as airworthy by numerous IA's over the years. Thus, the aircraft owner assumes that everything is legal & airworthy until I break the bad news to them.

Choose your IA,s wisely.

[visitor]

Looking at the propeller section of the 7AC "Aircraft Specification NO. A-759" (TCDS), indicates that a wood propeller not listed by make/model would be a legal installation on a 7AC provided it meets the limits specified in 1 (c).

[gellisor]

The prop was made to specs for the 7ac and has the sign off of an FAA official. Not just an IA.

[jerrymjr]

You should see a new revision to A-759 really soon.
Rev 67.

However, I garuntee there are no changes for the 7AC in it. hehe

Anyway, Don't take the TCDS as gospel all the time. Its only up dated once in a while and its NOT FAA approved data. Sure, they publish it, but its not actual technical data. Its only there for helpful information.

Where the above list of 3 items is missing is TC changes that are not listed on the TCDS. We see it alot with newly completed projects. For example, we have had a gross weight approved for the 7GCAA for about 5 years now. Do you see it on the TCDS? nope. (its in rev 67 though)

How does this affect you guys in this forum?
Not a lot, since we focus on the Citabria line and the 8 series. Sorry.

Ok, enough of a digression.

In order to put that Falcon prop on, you will need an STC. Either, they have one, or you'll have to get one of your own. (likely the One Time STC version). Feild Approval is still posible if its been done before to the point where the FISDO is happy with that. The trend in the last few years is to phase Feild Approvals out since the policy was far too inconsistant and FISDO is not responsible to be a Certification Engineer.