Torque for prop bolts

Scott wrote:
Quick question for the group. When setting the torque on prop bolts (I
have bolts with nuts), if the hole for the cotter pin doesn't line up
with the castleated nut at the proper torque setting, is it better to go
tighter or looser to get the hole lined up. My gut instinct says
tighter, but....

Scott
Use a pair of Belleville washers rated for about 2000 lb under each
bolt head, installed with their conacave sides facing each other. See
if you can get to the recently-deceased Vance Jaqua's web site, and see
his write-up on the Belleville use.

I have a metal prop on a tapered crank and as far as I know, there is no
requirement to check the torque periodically. The washer fix sounds
reasonable. Now, is there a limit of one washer or is two or three
acceptable?

Scott



wrote:
Why are you using castlelated nuts? Does the airframe or prop
manufactuer require their use?

Diamond aircraft uses fiberlock nuts on the DA-20 C1 which uses a wood
prop on the IO-240 engine.

My glider club uses fiberlock nuts on the Hoffman 4 bladed wood prop of
a PA-25 Pawnee 250 used for towing gliders.

Both these aircraft are type certificated, if fiberlock are good enough
for them.....

If you check the torque on a regular basis as all wood prop
manufactuers I know of require than you whill have no problems with
loose bolts.

Robert Mudd
Moriarty, NM
A&P I.A.



Scott wrote:

Quick question for the group. When setting the torque on prop bolts (I
have bolts with nuts), if the hole for the cotter pin doesn't line up
with the castleated nut at the proper torque setting, is it better to go
tighter or looser to get the hole lined up. My gut instinct says
tighter, but....

Scott

That is the answer I was looking for (a quote from AC 43.13)...I can't
find my copy. Now, can you define "friction drag" ? If I know what
that is, I'll have 'er whipped! Thanks!

Scott



Jester wrote:

Scott wrote:

Quick question for the group. When setting the torque on prop bolts (I
have bolts with nuts), if the hole for the cotter pin doesn't line up
with the castleated nut at the proper torque setting, is it better to go
tighter or looser to get the hole lined up. My gut instinct says
tighter, but....

Scott



From chapter 7 of the AC 43.13-1B


"f. When installing a castle nut, start
alignment with the cotter pin hole at the minimum
recommended torque plus friction drag
torque.

NOTE: Do not exceed the maximum
torque plus the friction drag. If the
hole and nut castellation do not align,
change washer or nut and try again.
Exceeding the maximum recommended
torque is not recommended."

This is also what I remember from school.

Jesse M.
PP-ASEL
A&P

Scott wrote:
That is the answer I was looking for (a quote from AC 43.13)...I can't
find my copy. Now, can you define "friction drag" ? If I know what
that is, I'll have 'er whipped! Thanks!

Scott

Friction drag is the drag exerted by the locking feature of the
nut, whether it's a nylon ring or a crimped metal collar. The amount of
torque required to turn the nut on the threads before any tension is
put on the bolt is added to the torque spec so that the proper tension
is achieved in the bolt (or stud). It can be critical especially with
all-metal locknuts; they are pretty tight on the threads.

Dan

Thanks! Got it! So I think there would be hardly any friction drag
with a castleated nut since there is no inherant locking mechanism built
into the nut...

Scott


wrote:

Scott wrote:

That is the answer I was looking for (a quote from AC 43.13)...I can't
find my copy. Now, can you define "friction drag" ? If I know what
that is, I'll have 'er whipped! Thanks!

Scott


Friction drag is the drag exerted by the locking feature of the
nut, whether it's a nylon ring or a crimped metal collar. The amount of
torque required to turn the nut on the threads before any tension is
put on the bolt is added to the torque spec so that the proper tension
is achieved in the bolt (or stud). It can be critical especially with
all-metal locknuts; they are pretty tight on the threads.

Dan

"jerry wass" wrote in message
.. .
pbc76049 wrote:

Hey, never thot of swappin nuts--thanx

My Pleasure... It's the simple stuff that makes life a joy.
Have a great say.....
Scott.