Ercoupe propeller installation

[Strutwipe]

I am request help from the forum. I am working, for free, on an Ercoupe 415C owned by a 85 year old gentleman. The idea is to get him back up and flying but I've came across a propeller problem.

I've installed propellers before but the bolt head has been on the aft side of the backplate. Throw on the propeller, torque down the castle nuts and pin, no problem. This propeller is installed with the bolt heads on the forward side of the prop. The threads go into the backplate of the C-75. My concern is there is no running torque on the backplate female fastener. The Ercoupe manual say to "Install" propeller. The continental manual has the bolt head on the aft side like I'm use to seeing. Continental has limited their tech support due to COVID so I've been waiting for a call back. I called Sensenich and they referred me to Continental.

Any gray breads out there that have dealt with this configuration and is there a running torque requirement? Also, where does one find the the required torque for the bolt head? SB maybe? I could not find one on FAA RGL pointing to this.

 

[Tom-D]

Wooden or metal?
Prop data please.
is that a prop that requires bel-ville (sp) washers?

 

[Bell206]

where does one find the the required torque for the bolt head?

Back in the day, prop install info was put out by the prop mfg'r. But as mentioned above, without the specific model prop you have, can't offer a direction to follow.

 

[Strutwipe]

Thanks guys. And I thought of everything......duh

Sensenich model M76A K-2 (aluminum). The bolts are installed only with flat washers, I doubled checked when I called Sensenich today. That is the weird thing, the only locking mechanism is the safety wire. The only instruction Sensenich offers is to install bolts clean with no lube, aka no loctite. They did provide one piece of trivial information that maybe important, the prop is 52 years old. The IA made sure all ADs and time till overhaul were good when he did the annual last year. The plane never went back together due to write ups that the gentleman could not afford to complete.

 

[Tom-D]

Sensenich model M76A K-2
doesn't require anything but the washers, head to the engine flange, and the flat washers and the nuts torqued to 25 foot pounds. and keyed.
http://www.sensenich.com/wp-content...ons_General_Metal_Instructions_1261679488.pdf

 

[Bell206]

That is the weird thing, the only locking mechanism is the safety wire.

Get your required torque from the install instruction link below. That's the whole purpose of the wire. If you think that's weird then don't look close at a helicopter. The whole thing is safety wired togather.
http://www.sensenich.com/documents/

 

[Strutwipe]

Thanks guys. I got hooked on the running torque. I did see these instructions but discounted them when they referred to installation of a spacer. But it does say when applicable. Looking over the TC clears things up.