Cont. A-65

[Dan Carlson]

I am receiving conflicting stories about the A-65. Are there two different shafts--- one for a metal prop and one for wood? It's amazing the stories you here in "the hangar". Thought I would pose this to the experts. It's for my BD-12 project. ( Sorry--I couldn't pass that up)

[VictorBravo]

Re: Cont. A-65

I am receiving conflicting stories about the A-65. Are there two different shafts--- one for a metal prop and one for wood? It's amazing the stories you here in "the hangar". Thought I would pose this to the experts. It's for my BD-12 project. ( Sorry--I couldn't pass that up)

There are two different shafts, one with an integral flange and one with a tapered end plus a flange adapter. If your data plate says "A-65-8F" then you have the integral flange.

[M Towsley]

Re: Cont. A-65

Dan,

If you have a tapered shaft you will also need a propeller hub for that shaft. A lot of people use wood propellers with a tapered shaft, but with the correct adapters, a metal one may also be used.

[Ragwing nut]

Re: Cont. A-65

Wood or metal props can be used on either crankshaft.

Mike

[Len Petterson]

Re: Cont. A-65

Are there different tapered hubs?
One for wood propps and one for Metal?
Would they have different part numbers from Continental?
Mine had a Flottorp wood proop at one time but for the last 1000 hr + it has flown with a metal one.
Am I asking a valid Question or -------
Len

[Robert Lees]

Re: Cont. A-65

Either prop will fit on either crankshaft.

Rob

[crispy critter]

Re: Cont. A-65

Either prop will work on both flange and taper shaft engines. NO, you do not have to change the taper shaft prop flange to use a different prop as long as the prop is for an A-65(or any 4 cylinder cont for that matter).The only thing you will have to change are the prop bolts because one uses longer bolts than the other. You also want to make sure to use crush plate over the front of a wood prop on either flange. The metal props don't need the crush plate but the wood props do, if you don't use the crush plates on the wood prop then your bolts will never stay tight and the bolt holes threw the wood prop will quickly become oversized.

[Ragwing nut]

Re: Cont. A-65

There are many different tapered prop hubs, but only one for the 65,75,85 Continentals. The only difference in the propellers in using them on either flange is on the intergal hub, the prop must be counterbored to go over the prop nuts in the flange. That same propeller can be used on a removable hub if aluminum bushings are installed in the holes. If the prop is not counterbored, to use it on a intergal flange, it will need to be counterbored.

Mike

[Robert Lees]

Re: Cont. A-65

Most props I've seen (both wood and metal) have the counterbore already there
...and if using the removable hub, please install the prop bolts before torquing the hub on.

I still use the crush plate even on metal props, if only to help the cg a little bit.

[crispy critter]

Re: Cont. A-65

Rob,
I had a friend with a champ once and it had a vibration we never could find until we decided to change the prop to see if that would solve the problem. It had a metal prop with the crush plate on the front of it. When we removed the crush plate from the front of the prop the problem was very obvious, it had let moisture get trapped in there and the entire front, inside, bolt & bolt holes of the prop, and the prop flange were completly eat up in corrosion. There was also bad pitting on the tapered part of the crank causing him to replace the crank. It's a wonder the prop was still attached to the engine......it was that bad. I told a couple of old school IA's about what we found and they said never use a crush plate on a metal prop. I asked them why, it looks like a skull cap spinner would do the same thing( I was young and didn't know much).They said no because the spinner was not a tight metal to metal fit and would allow it to breath and let moisture escape, also it was as simple as removing one screw to let you access the front of the prop for inspection(which they said most IA's neglect to do) and with the crush plate there to hide everything it would be easy to go un-noticed for years because no,or very few,IA's even look at this place for problems unless an AD comes out to inspect.

[Robert Lees]

Re: Cont. A-65

...but shirley everyone removes the prop at annual time to check for corrosion?

Well we do.

The crush plate nicely centres the skull-cap, too!

[M Towsley]

Re: Cont. A-65

Rob,

When you say install the prop bolts, you mean install the prop, torque the bolts, then install the prop/hub onto the engine? Or, just install the bolts because there may not be clearance behind the hub? Just got a spare A-75 with a tapered shaft and these are new to me. Thanks.

[Robert Lees]

Re: Cont. A-65

That's it, Marty, the bolts need to be inserted through the hub of a tapered crank before the hub is tightened on, else you can't get the bolts in!

(Not a problem with the flanged crank, because the bolts go in from the front)

[high time cub]

Re: Cont. A-65

More pros and cons....

Like Robert, I use a crush plate with a metal prop. The 45 degree chamfered edge of the plate spreads and centers the scull cap spinner giving it a bit more purchase.
Aesthetically, I like the visual transition it makes between the flat prop surface and bulbous spinner as in the base of a Roman column.

35 years ago, I had a scull cap (sans plate) come off in flight, the prop cut it in two and received a nice ding from the center self tapping screw.

Most crush plates have a center hole so you can inspect the bore. A friend of mine, has an original "Powered By Continental" solid center plate on a wood prop installation.

To crush or not to crush? Whatever.....If you have a scull cap, do your expensive propeller a favor and replace the center self tapping screw/ tinnerman with a proper AN screw and nut plate.

[crispy critter]

Re: Cont. A-65

I agree, anytime you use a skull cap spinner always replace the sheet metal screw with a machine screw and nut plate.. As for the crush plate on a metal prop....I will never use it, and if you do please make sure to pull the prop,clean,lubricate, and inspect every year. Also just to add to the subject for anyone using a wood prop, please never use the wood prop without the crush plate.