Shortened McCauley Propeller on an O-300

A year or so ago there was a thread about shortened aluminum prop blades,
especially on Sensenich props, going into flutter and departing O-320's.
And I recall that Rich Shankland decided not to use the bargain prop he had
bought for his Emeraude.

Now here's an aluminum McCauley which was originally 76" and is now 75.188.
In other words 13/32" have been removed from each blade, reducing its
diameter by 13/16".

It seems ac 43.13A, McCauley, or the tcds ought to say something about this
and the limits a prop may be shortened but I haven't found it yet. Anybody
know if this prop would be legal on a certified aircraft with a Continental
O-300? Or can direct us to the pertinent specs?
Thanks.

What is the prop Model?
"Larry Smith" wrote in message
...
A year or so ago there was a thread about shortened aluminum prop blades,
especially on Sensenich props, going into flutter and departing O-320's.
And I recall that Rich Shankland decided not to use the bargain prop he
had
bought for his Emeraude.

Now here's an aluminum McCauley which was originally 76" and is now
75.188.
In other words 13/32" have been removed from each blade, reducing its
diameter by 13/16".

It seems ac 43.13A, McCauley, or the tcds ought to say something about
this
and the limits a prop may be shortened but I haven't found it yet.
Anybody
know if this prop would be legal on a certified aircraft with a
Continental
O-300? Or can direct us to the pertinent specs?
Thanks.

If it was on a Cessna 170, then ...
Propeller
(a)
McCauley 1A170
33 lb.
(-39)
(-39)
(-39)
Static r.p.m. at max. permissible throttle setting:
Landplane: Not over 2330, not under 2230
Seaplane (Models 170A and 170B): Not over 2525, not under 2300.
No additional tolerance permitted.
Diameter: Not over 76 in., not under 74.5 in.
Propeller spinner, dwg. No. 0550101-3
-eligible-
Propeller spinner, dwg. No. 0550162
2 lb.
(-39)
(-39)
(-39)
So you current length should be O.K. The problem of prop shortening I believe was when they chopped several inches below the minimum approved length.

"Larry Smith" wrote in message ...
A year or so ago there was a thread about shortened aluminum prop blades,
especially on Sensenich props, going into flutter and departing O-320's.
And I recall that Rich Shankland decided not to use the bargain prop he had
bought for his Emeraude.

Now here's an aluminum McCauley which was originally 76" and is now 75.188.
In other words 13/32" have been removed from each blade, reducing its
diameter by 13/16".

It seems ac 43.13A, McCauley, or the tcds ought to say something about this
and the limits a prop may be shortened but I haven't found it yet. Anybody
know if this prop would be legal on a certified aircraft with a Continental
O-300? Or can direct us to the pertinent specs?
Thanks.

"Larry Smith" wrote in message
...
A year or so ago there was a thread about shortened aluminum prop blades,
especially on Sensenich props, going into flutter and departing O-320's.
And I recall that Rich Shankland decided not to use the bargain prop he
had
bought for his Emeraude.

That's correct, so I sold it for a wall hangar, with the warning that it
should not be used. Then later as I was talking to a fellow who, along with
several friends, were facing the purchase of new props to replace those on
their RV's which had been similarly shortened. He told me that they had
solved the problem by having their props harmonically tested, finding the
critical frequency, and placarding them for operation in that rpm range
(with adequate safety margins above and below the critical center).

I'm just as happy without it, though; as I like to be able to select "slow
cruise" rpm settings which would fall right at the common critical rpm
range. Another factor in my decision was that Northwest propellers declined
to inspect or magnaflux it, stating that they do not touch props which have
been modified beyond factory limits, due to the liability involved. This
prop was shortened something like 3" on each end - well beyond the factory
limits for that model.
]
Besides which, I paid $75 for it at a garage sale and got $375 for it on
eBay - as a wall hangar!

Rich S.

"Rich S." wrote in message
...
[...] Besides which, I paid $75 for it at a garage sale and got $375 for
it on
eBay - as a wall hangar!

Rich S.

Good for you. Shrewd fella.

Thanks, Cy, for your usual splendid courtesy. I found the tcds for the AIQ and it permits a prop of diameter no less than 75.5" so I don't think this prop is legal for it.
"Cy Galley" wrote in message news:jPl7b.406837$uu5.73583@sccrnsc04...
If it was on a Cessna 170, then ...
Propeller
(a)
McCauley 1A170
33 lb.
(-39)
(-39)
(-39)
Static r.p.m. at max. permissible throttle setting:
Landplane: Not over 2330, not under 2230
Seaplane (Models 170A and 170B): Not over 2525, not under 2300.
No additional tolerance permitted.
Diameter: Not over 76 in., not under 74.5 in.
Propeller spinner, dwg. No. 0550101-3
-eligible-
Propeller spinner, dwg. No. 0550162
2 lb.
(-39)
(-39)
(-39)
So you current length should be O.K. The problem of prop shortening I believe was when they chopped several inches below the minimum approved length.

"Larry Smith" wrote in message ...
A year or so ago there was a thread about shortened aluminum prop blades,
especially on Sensenich props, going into flutter and departing O-320's.
And I recall that Rich Shankland decided not to use the bargain prop he had
bought for his Emeraude.

Now here's an aluminum McCauley which was originally 76" and is now 75.188.
In other words 13/32" have been removed from each blade, reducing its
diameter by 13/16".

It seems ac 43.13A, McCauley, or the tcds ought to say something about this
and the limits a prop may be shortened but I haven't found it yet. Anybody
know if this prop would be legal on a certified aircraft with a Continental
O-300? Or can direct us to the pertinent specs?
Thanks.

Propeller and propeller
limits from the 172 TCDS
1.
Propeller
(a)
McCauley 1A170
Static rpm at maximum permissible throttle setting:
Not over 2360, not under 2230
No additional tolerance permitted
Diameter: not over 76 in., not under 74.5 in.
"Larry Smith" wrote in message ...
Thanks, Cy, for your usual splendid courtesy. I found the tcds for the AIQ and it permits a prop of diameter no less than 75.5" so I don't think this prop is legal for it.
"Cy Galley" wrote in message news:jPl7b.406837$uu5.73583@sccrnsc04...
If it was on a Cessna 170, then ...
Propeller
(a)
McCauley 1A170
33 lb.
(-39)
(-39)
(-39)
Static r.p.m. at max. permissible throttle setting:
Landplane: Not over 2330, not under 2230
Seaplane (Models 170A and 170B): Not over 2525, not under 2300.
No additional tolerance permitted.
Diameter: Not over 76 in., not under 74.5 in.
Propeller spinner, dwg. No. 0550101-3
-eligible-
Propeller spinner, dwg. No. 0550162
2 lb.
(-39)
(-39)
(-39)
So you current length should be O.K. The problem of prop shortening I believe was when they chopped several inches below the minimum approved length.

"Larry Smith" wrote in message ...
A year or so ago there was a thread about shortened aluminum prop blades,
especially on Sensenich props, going into flutter and departing O-320's.
And I recall that Rich Shankland decided not to use the bargain prop he had
bought for his Emeraude.

Now here's an aluminum McCauley which was originally 76" and is now 75.188.
In other words 13/32" have been removed from each blade, reducing its
diameter by 13/16".

It seems ac 43.13A, McCauley, or the tcds ought to say something about this
and the limits a prop may be shortened but I haven't found it yet. Anybody
know if this prop would be legal on a certified aircraft with a Continental
O-300? Or can direct us to the pertinent specs?
Thanks.

"Bela P. Havasreti" wrote in message ...
On Tue, 9 Sep 2003 09:49:51 -0400, "Larry Smith"
wrote:

What model McCauley prop?

My B model Cessna 170 Type Certificate sheet says the permissible
lengths for a 1A170DM McCauley prop is 76" max and 74.5" min.

I see the 1A170 74-76" on O-300's on Aeronca 15AC,
74.5-76 on the Cessna 172
73-74 on the Maule M4

1A175 78.4-80 on the 172 Seaplane.

1C172 74.5-76 on the Maule M4
74-76 on the Super Rallye

That's the only combinations of MacCauley fixed props and O-300's I can find
in the type certificate database.

In article ,
Rich S. wrote:
"Larry Smith" wrote in message
...
A year or so ago there was a thread about shortened aluminum prop blades,
especially on Sensenich props, going into flutter and departing O-320's.
And I recall that Rich Shankland decided not to use the bargain prop he
had
bought for his Emeraude.

That's correct, so I sold it for a wall hangar, with the warning that it
should not be used. Then later as I was talking to a fellow who, along with
several friends, were facing the purchase of new props to replace those on
their RV's which had been similarly shortened. He told me that they had
solved the problem by having their props harmonically tested, finding the
critical frequency, and placarding them for operation in that rpm range
(with adequate safety margins above and below the critical center).

I'm just as happy without it, though; as I like to be able to select "slow
cruise" rpm settings which would fall right at the common critical rpm
range. Another factor in my decision was that Northwest propellers declined
to inspect or magnaflux it, stating that they do not touch props which have
been modified beyond factory limits, due to the liability involved. This
prop was shortened something like 3" on each end - well beyond the factory
limits for that model.
]
Besides which, I paid $75 for it at a garage sale and got $375 for it on
eBay - as a wall hangar!

An a-prop-riate ending for it!

"Robert Bonomi" wrote in message
...
In article ,
Rich S. wrote:
That's correct, so I sold it for a wall *hangar*, (snip)
Besides which, I paid $75 for it at a garage sale and got $375 for it on
eBay - as a wall *hangar*!

An a-prop-riate ending for it!

Gadzooks! I just spotted my spelling error. Have at me, BOb.

Rich "Habit forming" S.