Propellor Install - Proper Clockwork Postion?

[charly]

Hello all. Just had my McCauley 1A170 overhauled by Sensenich in Lancaster, PA. I do not have a service manual. I would like to know how to match the prop to the correct "clockwork" position on the hub. I have 1952 B model with a C145. Can anyone help? BTW, Sensenich was extremely accomodating to my unannouced drop off last Friday. Spec'd out my prop on the spot to be sure it met min.s to undergo overhaul. VERY friendly, knowledgable folks. Thank you! R

[1SeventyZ]

Stand in front of the aircraft, looking backward at it.

With the prop flange 0 tick mark (on backside of flange) pointing downward so it's at the 6 o'clock position, aligned with the split in the case, hang the prop so that the #1 blade points up and left to the approx 10:30 position.

This is how I remember it at least. Pretty sure I learned it here. It sure does smooth it out though to have it indexed properly.

[Bruce Fenstermacher]

1Seventy Z has it about right. The crank should be at TDC on the #1 cylinder and then when viewed from the front as you install the prop the #1 blade at about 10:30 (it would be 1:00 if viewed from behind as stated in manuals and service information

From an 2008 post by Gary

Bill,
It sounds like your prop is mounted correctly. The information is on page 45 of the Cessna 170 book. With the # 1 cyl. at TDC your prop should be at the one o'clock position as viewed from behind.

It's interesting to read the "chatty" way service newsletters were written in earlier times:

DATE: 7-8-53
SUBJECT: 45' Advance of 170 Props

Had a chance to fly a '54-170 and what a suprise. Among the several improvements in the '54 Model is the noticeable improvement in engine smoothness. It's been accomplished by advancing the prop 45' or one bolt hole in the crankshaft. Engineering reports as much as 50% reduction in the amplitude of vibration, whatever that is, but it sure does the trick and can be done on earlier 170's in the field.

All 170's beginning with 26110 have the prop advanced.

[charly]

Hi 1SeventyZ and Bruce! That should do the trick! I am very grateful for your prompt replies as I would like to get prop back on this Saturday. Will let you know how it works. R

[GAHorn]

... I do not have a service manual. ...

Did you realize you just published on the WWW that you are illegally performing maintenance?

Even tho' the 100 Series Service Manual, 1962 and Prior does not provide the information you need,... you are still required to have it available, while your certificated repairman (A&P) personally supervises your work.

(I'm on a tear this AM.)

[N2255D]

... I do not have a service manual. ...

Did you realize you just published on the WWW that you are illegally performing maintenance?

Even tho' the 100 Series Service Manual, 1962 and Prior does not provide the information you need,... you are still required to have it available, while your certificated repairman (A&P) personally supervises your work.

(I'm on a tear this AM.)

He just wanted to get familiar with the procedure for when his A&P gets there with the manual to supervise the installation .

[jrenwick]

... I do not have a service manual. ...

Did you realize you just published on the WWW that you are illegally performing maintenance?

He didn't actually say that. This forum is such a terrific source of good maintenance information, I'm sure it makes a significant contribution to overall flight safety. I certainly wouldn't want to see these discussions limited to participants who are licensed to perform maintenance.

On the other hand, people do need to be aware that what you say here can be read by absolutely anybody, in any part of the world, and you have no control over what they may think or do about it.

[cessna170bdriver]

The only place I've EVER seen the proper propeller positioning procedure published for a 170 is in our Association documents, none of which are approved by anyone other than maybe our editorial board. That doesn't change the physics involved, and if you don't believe it's correct, just try moving the propeller one hole one way or another. Ask me how I know...

[bsdunek]

I'm at work and can't look it up, but I seem to remember a Cessna Service Bulletin from the late 50's about repositioning the propeller from the original factory position. I remember Dad doing it and commenting that it was smoother.

[charly]

LOL! Thanks for busting my chops all who castigated me for an illegal maintenance procedure that hasn't yet happened.
I promise you, my IA will be doing the work to make this legal along with proper log entry. I just wanted to provide the recommended service procedure so he wouldn't have to fish for it. Thanks for the sporting remarks!! R

[Bruce Fenstermacher]

I'm at work and can't look it up, but I seem to remember a Cessna Service Bulletin from the late 50's about repositioning the propeller from the original factory position. I remember Dad doing it and commenting that it was smoother.

Bruce I believe the quoted text in my early post is the Service Bulletin verbatim. It is included as part of a Cessna published summary of service information a copy of which was given to convention maintenance forum attendees by George a few years ago. I believe the association has copies for sale.

[GAHorn]

... I do not have a service manual. ...

Did you realize you just published on the WWW that you are illegally performing maintenance?

He didn't actually say that. This forum is such a terrific source of good maintenance information, I'm sure it makes a significant contribution to overall flight safety. I certainly wouldn't want to see these discussions limited to participants who are licensed to perform maintenance.

On the other hand, people do need to be aware that what you say here can be read by absolutely anybody, in any part of the world, and you have no control over what they may think or do about it.

My comment was taken out-of-context. It was tongue-in-cheek (as evidenced by the which was edited-out.) It was merely an attempt to point out that the Service Manual, while not an all-encompassing document, is nevertheless a necessary one, which all owners should have if they intend to participate in maintaining their airplanes.

My method was only intended to add levity to the discussion.

The only place I've EVER seen the proper propeller positioning procedure published for a 170 is in our Association documents, none of which are approved by anyone other than maybe our editorial board. That doesn't change the physics involved, and if you don't believe it's correct, just try moving the propeller one hole one way or another. Ask me how I know...

The Cessna Service Bulletin Index I provided attendees at the Kelowna Seminar has, as it's first topic, a Service News Letter dated 7-8-53 regarding the need to re-locate the propeller.

[bsdunek]

I'm at work and can't look it up, but I seem to remember a Cessna Service Bulletin from the late 50's about repositioning the propeller from the original factory position. I remember Dad doing it and commenting that it was smoother.

Bruce I believe the quoted text in my early post is the Service Bulletin verbatim. It is included as part of a Cessna published summary of service information a copy of which was given to convention maintenance forum attendees by George a few years ago. I believe the association has copies for sale.

Just a couple of the great things about belonging to the association. Guess the service bulletin was earlier than I remember - George says 1953.

[SUNDBY]

Correct me if i'm wrong (heaven forbid), I was of the understanding that a C-145 with an undampened crankshaft doesn't care what position the propellor is placed at. Or maybe I got lucky when I, I mean my FAA licensed mechanic, put my prop on.

[GAHorn]

Correct me if i'm wrong (heaven forbid), I was of the understanding that a C-145 with an undampened crankshaft doesn't care what position the propellor is placed at. Or maybe I got lucky when I, I mean my FAA licensed mechanic, put my prop on.

Yep. You're wrong. The early Service Bulletin specifically applied to undampened cranks (as well as all subsequent, which the factory "clocked" the prop correctly at original assembly.)

(If it helps your self-esteem.... the wooden props which were common in the earliest production were less susceptible to noticeable vibration. It was after metal props became more popular, and complaints increased, that the factory began to pay attention to such matters.)