Installing a wood prop...

On Tue, 19 Jul 2005 09:54:02 -0700, "Rich S."
wrote:

Don't forget to track the prop to make sure the blades run in the same plane
within the limits established by the prop maker (usually 1/16" - 1/8" or
so).

Rich S.

Rich, if it isn't, how do you fix that? I've heard this a lot and it
makes sense that you want the prop tracking properly, but how do you
do it?

Corky Scott

On Wed, 20 Jul 2005 09:05:52 -0400, Corky Scott
wrote:

Rich, if it isn't, how do you fix that? I've heard this a lot and it
makes sense that you want the prop tracking properly, but how do you
do it?

Nevermind Rich, jls answered the question.

Corky Scott

"Corky Scott" wrote in message
...
On Wed, 20 Jul 2005 09:05:52 -0400, Corky Scott
wrote:

Rich, if it isn't, how do you fix that? I've heard this a lot and it
makes sense that you want the prop tracking properly, but how do you
do it?

Nevermind Rich, jls answered the question.

Corky........

I've been able to adjust the track on my prop about 1/16" by varying the
torque on the bolts slightly (but still within upper & lower limits). It is
now within 1/16" of perfect - close enough for me. If it was 1/8" and
wouldn't straighten out further, I'd send it back to the maker; assuming my
prop flange was dialed in.

Speaking of that, I guess if a prop flange was off a few thousandths, you
could set up the prop on the flange so the errors would tend to cancel out.

Rich S.

"Corky Scott" wrote in message
...
On Wed, 20 Jul 2005 09:05:52 -0400, Corky Scott
wrote:

Rich, if it isn't, how do you fix that? I've heard this a lot and it
makes sense that you want the prop tracking properly, but how do you
do it?

Nevermind Rich, jls answered the question.

Corky Scott


To find the prop's track, I stand a stool or small ladder as close to the
tip as possible, first fore, then aft of the prop's circumference. You
pull the prop through with all wheels tightly chocked and the top plugs
removed. When the prop is tracked properly, both tips will track the same
cat's hair -- in the direction of the longitudinal axis of the aircraft--
from the edge of the stool, or whatever makeshift pointer you may erect for
the purpose, like for example a screwdriver tip or ice pick c-clamped to a
small stepladder. You can also find if the prop blades are same length
too.* Do it in the hangar, not outside in the wind.

Sometimes a crankshaft flange out of limits will throw you when the prop may
be OK. I've seen it and done a lot of head-scratching until we did a runout
on the steel flange. There are prop-struck flanges out there with big
double-digit runouts on them, which of course you find with a good dial
indicator. 36 or so inches out to the tip and that flange slop is
magnified.


*We had an aircraft which had a pre-buy done, and the owner was upset to
hear his aluminum blades were unequal by a quarter inch. We set up a
pointer and showed him they were in fact dead nuts equal. Measuring helps
too, of course.

Pointers or dial indicators are also great for meticulous installation of a
spinner. There's nothing more obnoxious than a spinner wobbling like hell
while the engine idles.

Yesterday at KFQD I saw the world's most beautiful 1946 Globe Swift. That
thing was a joy to behold and when the 6-cylinder IO-360 Continental engine
sprang into motion, the polished aluminum spinner tracked to the naked eye
like it had been put on using a dial indicator. It is said you can buy that
aircraft for something in excess of 100k. See Van Van der Ploeg in
Greenville, SC.

Newspaper shims work very well for wood props.

"Rich S." wrote in message
...
"Corky Scott" wrote in message
...
On Wed, 20 Jul 2005 09:05:52 -0400, Corky Scott
wrote:

Rich, if it isn't, how do you fix that? I've heard this a lot and it
makes sense that you want the prop tracking properly, but how do you
do it?

Nevermind Rich, jls answered the question.

Corky........

I've been able to adjust the track on my prop about 1/16" by varying the
torque on the bolts slightly (but still within upper & lower limits). It
is now within 1/16" of perfect - close enough for me. If it was 1/8" and
wouldn't straighten out further, I'd send it back to the maker; assuming
my prop flange was dialed in.

Speaking of that, I guess if a prop flange was off a few thousandths, you
could set up the prop on the flange so the errors would tend to cancel
out.

Rich S.

What happens if you fly through rain? Wouldn't waxed paper or plastic cut
from a baggie be a bit more robust?

Jim


"Cy Galley" wrote in message
news:SgxDe.190403$nG6.163164@attbi_s22...
Newspaper shims work very well for wood props.

The prop is clamped so tight that water just can't into the crack. Unless
you dunk it into a lake everything should be ok. Remember wood also absorbs
water. If you feel better about using a bond paper, be my guest. I have
heard people using pop can material as well.





"RST Engineering" wrote in message
...
What happens if you fly through rain? Wouldn't waxed paper or plastic cut
from a baggie be a bit more robust?

Jim


"Cy Galley" wrote in message
news:SgxDe.190403$nG6.163164@attbi_s22...
Newspaper shims work very well for wood props.

"Cy Galley" wrote in message
news:SgxDe.190403$nG6.163164@attbi_s22...
Newspaper shims work very well for wood props.

Not to pirate the thread, but I decided to do absolutely everything I could
to insure a safe and comfortable trip to Oshkosh (Leaving at oh-dark-thirty
tomorrow!). I have the honor of being navigated this year by Lt. Col. R.
"Ken" Wheeler, USAF (ret). He flew in B-17's of the 12th. AF out of Italy.
He deserves every amenity my poor Emeraude can offer.

Towards that end, I flew to Thun Field (1S0) this afternoon and engaged the
gentlemen at NW Propellers to dynamically balance my wooden prop.

This prop is an Ed Sterba 74" x 62" which is three years old. I just
refinished it and statically balanced it. I tapped a 3/4" cold-rolled steel
rod through the center hole and suspended that on two jointer blades which
were set up level. Well, the prop vibrated somewhat before I refinished it
and I can't really say it was any better or worse when I got done. I did
feel a bit of vibration at cruise rpm, say 2400, which increased as the
throttle was reduced, peaking out at 1800 rpm when I could actually see
Weird Jim's audio panel blur.

So, off to the prop men. They had me remove the upper cowl and tie the tail
securely. The prop guy installed a transducer on the forward crankcase
center bolt and had me get back in the plane. The procedure would be to
start the engine, let the oil pressure stabilize, then when I was ready, run
it up to 2000 rpm. I did so, he looked at his gauges, shone (shined?) a
strobe at the prop, then signaled me to back off the throttle and cut the
engine.

He looked things over, picked one of the holes on the starter ring
gear/flywheel and added a bolt, nut, and three washers. One of the other
lads hollered over and said, "How close was it?". He answered, "Point six
four". I had no idea what that meant, so he explained. ".64 Inches per
second (IPS) is the extent of the vibration. Most folks show up with about
that or a bit less. Our goal is to get it less than .2 IPS."

We reran the test and he removed a washer. Ditto again. The next time he
spread out the weight over two bolt holes. That did it! The reading now was
..18 IPS. He said that occasionally they get lucky and make .15 IPS, but not
often.

I can't say that the vibration at cruise is a great deal less, but it is
noticeably reduced. Where it makes a big difference is at somewhat reduced
rpm. Now, when the throttle is backed off, the vibration just flat goes
away. I guess the $150 fee is worth it in the long run for comfort, if not
for instrument longevity and fewer cracks in things like the engine baffles.

Rich S.

Thinking about your question, wax paper is out as props are driven only by
friction. Wax paper would cut that friction.


"Cy Galley" wrote in message
news:j1zDe.190425$xm3.63278@attbi_s21...
The prop is clamped so tight that water just can't into the crack. Unless
you dunk it into a lake everything should be ok. Remember wood also
absorbs water. If you feel better about using a bond paper, be my guest. I
have heard people using pop can material as well.





"RST Engineering" wrote in message
...
What happens if you fly through rain? Wouldn't waxed paper or plastic
cut from a baggie be a bit more robust?

Jim


"Cy Galley" wrote in message
news:SgxDe.190403$nG6.163164@attbi_s22...
Newspaper shims work very well for wood props.

In article XE9De.40420$DC2.33578@okepread01,
Gig 601XL Builder wr.giacona@coxDOTnet wrote:

"SteveR" wrote in message
...

Tonight I'm going to install a prop on my plane (Pietenpol with a
Continental A-75) and go up for a quick flight. I've never done a prop
install before, so I want to make sure I get it right.

I figured I'll torque the bolts, run the plane for 10-15 minutes on the
ground, check the torque, take it up for a brief test flight, then check
the torque again. Any tips or things I should be careful for or watch
for? I'm a little nervous as I'll be doing it without anyone looking
over my shoulder.


--
SteveR


If the prop flys off land immediately.

If the prop flys off -- make sure that the rest of the plane stays in
formation with it! *grin*