[Michael Burbidge]

I'm installing my catto prop. I have a few questions. I'm building an RV-9A, with a Lycoming O320-D3G, standard Vans Pink Cowl. I have the standard Sabre prop extension.

My question is, where do the two spinner mounting plates go in relation so the other components?

And what is the technique and torque values for installing the prop to the extension. Sabre comes with instructions for installing the extension to the engine.

Here's a crude diagram of the components, as I understand them.

In relation to these components, where does the backing plate go? And where does the forward spinner mounting plate go?

Thanks for your help!
Michael-

 

[Greg Arehart]

In front of the crush plate and between the prop and extension.

42 pound-feet in typical (should give this number on the label on your prop). Install bolts and torque to ~32, then 37, then 42 (or whatever the final torque is for your prop if different from 42). Safety wire. Go fly for an hour, come back and check the torque. Mine has never needed adjustment once properly torqued, but worth checking.

Greg

 

[N941WR]

The spinner bulkheads go on either side of the prop, flanges facing aft.

 

[Michael Burbidge]

Like this...

Greg and Bill contradicted each other on the front plate, I think. Is the complete picture like this?

Yup, the torque is on my prop. 38 lbs. is what it says. Obviously ft-lbs.

Thanks,
Michael-

 

[crabandy]

Bill and Greg are correct, I found a couple pics. Torque for the 0-360 bolts on the Catto for my prop were 42 ft/lbs, not sure if it's the same for the smaller bolts on the 0-320.

 

[N941WR]

Greg and Bill contradicted each other on the front plate, I think. Is the complete picture like this?

Yup, the torque is on my prop. 38 lbs. is what it says. Obviously ft-lbs.

Thanks,
Michael-

That is correct.

Once every thing is set, mark all the parts and one prop blade so you can reassemble it in exactly the same way. (This also helps, when and if, you get it balanced.

 

[Michael Burbidge]

Thanks!

Perfect. Thanks for the pictures and responses!

Michael-

 

[crabandy]

I had Craig cut my spinner and drill it to the bulkheads, It fits very well but only when clocked properly. As said above mark 1 blade cutout on each spinner bulkhead to align the bulkheads to the prop and there is just enough play in the bulkheads (while the prop bolts are still loose) that I must twist the rear spinner bulkhead counterclockwise and twist the front bulkhead clockwise to get the screws to line up. It is a very slight movement but I've safety wired the prop bolts on before and my spinner to spinner bulkhead holes didn't line up.

 

[Michael Burbidge]

My bad...

When you are at the finishing stages of the build, you just get used to having no instructions or drawings. It's been awhile since I've looked at either. I pulled out the manual to see if there were instructions describing fitting the spinner and low and behold there was a drawing detailing the very questions I've been asking here.

Sorry,
Michael-

 

[Greg Arehart]

Sorry, my mistake, Bill is correct, the crush plate is in front of the bulkhead. And like others have said, worth clocking all these parts so that the spinner ends up with the holes lined up properly.

You may want to add some tape to the front bulkhead between the bulkhead and spinner if they don't fit really tight. I recently had a spinner screw break off (yes, broke, not just backed out) and hit one of the blades. Just a ding at first, then turned into a stress fracture after ~10 hours of flying. I had Craig replace the metal leading edge (when he took it off, it really fractured!). His take was that if there is any space between the spinner and bulkhead, it puts a lot of stress on the screw, so it is best to add a layer or two of tape (we used leading edge tape, but probably anything would work) to fill that gap.

Greg

 

[N941WR]

...You may want to add some tape to the front bulkhead between the bulkhead and spinner if they don't fit really tight. ...

Greg

I did the same and then a friend suggested I use some bathroom silicone between the bulkhead and the inside of the spinner.

Great idea BUT...

If you get any silicone on the surfaces to be painted, you will never get paint to stick. (My spinner was painted when I tried this trick.)

Finally, I glued that stinking spinner to my bulkheads and it was close to a year before I could get spinner off. DUH!

The good news is that the spinner fits tight.

I think my mistake was that I put the silicone around the bulkheads, put the spinner on, screwed it in place, and waited for it to dry. On second thought, it would have worked better had I screwed the spinner in place and then removed it and waited for it to cure before reinstalling it.

 

[Neal@F14]

If you run a bead of RTV silicone around the edge of the front spinner bulkhead, wrap a strip of Saran Wrap around the RTV, then put the spinner on and secure with a few screws, then let the RTV dry overnight and remove the spinner. The Saran Wrap will keep you from gluing the spinner to the bulkhead. Next, remove the Saran Wrap and trim away any excess cured silicone rubber from the bulkhead with a razor blade. Next, smear a paper thin layer of fresh RTV over the cured RTV and let it dry completely to fill the tiny gap left from the Saran Wrap. That will give you a gapless, silicone-filled layer between the front bulkhead and the inside of the spinner that will be a perfect fit. The spinner will come off easily when you need to remove it, since it isn't glued to the bulkhead, and you'll have a nice rubber-cushioned tight fit between the front bulkhead and inside of the spinner cone. Some folks do this with Pro-Seal instead of RTV silicone. I used Permatex "Ultra Gray" RTV this way on my front spinner bulkhead. The Ultra Gray dries a little harder than other RTV silicones, and is just about the same hardness as cured Pro-Seal.