Aluminum Prop Dings

Hi All

I'm repainting my McCauley Aluminium prop and was wondering if anyone can
give me some guidance in regards to the little aluminums dings that occurred
on the back side of the tip on the prop. These are tiny dings the prop has
picked up over the years from sucking up debris while taxing. They vary
from tiny pin pricks to small scratches, maybe .015" at the deepest and
maybe about .05" inches long.

I'm not sure if I should try and dress these out with a sander (grinder)
because to get them all out, I'd be taking off some serious aluminium.

Any tips on sanding would be appreciated.

Thanks

Eugene

This is a very serious question and one that deserves a professional answer.
Visit a propeller shop and look at their scrap pile. There's plenty of
evidence of what a pit or scratch can do. Talk it over with the shop
manager.

Warning, this will be a VERY sobering visit.

bildan

"canflyboy" wrote in message
...
Hi All

I'm repainting my McCauley Aluminium prop and was wondering if anyone can
give me some guidance in regards to the little aluminums dings that
occurred
on the back side of the tip on the prop. These are tiny dings the prop
has
picked up over the years from sucking up debris while taxing. They vary
from tiny pin pricks to small scratches, maybe .015" at the deepest and
maybe about .05" inches long.

I'm not sure if I should try and dress these out with a sander (grinder)
because to get them all out, I'd be taking off some serious aluminium.

Any tips on sanding would be appreciated.

Thanks

Eugene

The curved side of the blade is called the "back" or "cambered side". The
flat side is called the "face" or "thrust side". The back usually doesn't
get many nicks in it. AC43-13-1B change 1 has all the information you
could desire about blending out nicks in your propeller, including
limitations. You shouldn't repaint the blade without closely inspecting
and repairing the nicks, You might paint over a developing crack.



"canflyboy" wrote in
:

Hi All

I'm repainting my McCauley Aluminium prop and was wondering if anyone
can give me some guidance in regards to the little aluminums dings
that occurred on the back side of the tip on the prop. These are tiny
dings the prop has picked up over the years from sucking up debris
while taxing. They vary from tiny pin pricks to small scratches,
maybe .015" at the deepest and maybe about .05" inches long.

I'm not sure if I should try and dress these out with a sander
(grinder) because to get them all out, I'd be taking off some serious
aluminium.

Any tips on sanding would be appreciated.

Thanks

Eugene





--
J Kimmel

www.metalinnovations.com

"Cuius testiculos habes, habeas cardia et cerebellum." - When you have
their full attention in your grip, their hearts and minds will follow.

guynoir wrote:
The curved side of the blade is called the "back" or "cambered side". The
flat side is called the "face" or "thrust side". The back usually doesn't
get many nicks in it.

I get more dings in the back (the side facing the pilot) than I ever get
in the front.

The side facing the pilot is the face. The side away from the pilot is the
back, unless you fly a pusher.

Ron Natalie wrote in
m:

guynoir wrote:
The curved side of the blade is called the "back" or "cambered side".
The flat side is called the "face" or "thrust side". The back
usually doesn't get many nicks in it.

I get more dings in the back (the side facing the pilot) than I ever
get in the front.




--
J Kimmel

www.metalinnovations.com

"Cuius testiculos habes, habeas cardia et cerebellum." - When you have
their full attention in your grip, their hearts and minds will follow.

On Wed, 25 May 2005 14:00:21 -0500, guynoir
wrote:

The side facing the pilot is the face. The side away from the pilot is the
back, unless you fly a pusher.

That terminology is as intuitively backwards as some of the computer
stuff I work with.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Ron Natalie wrote in
om:

guynoir wrote:
The curved side of the blade is called the "back" or "cambered side".
The flat side is called the "face" or "thrust side". The back
usually doesn't get many nicks in it.

I get more dings in the back (the side facing the pilot) than I ever
get in the front.

In article ,
Roger wrote:
On Wed, 25 May 2005 14:00:21 -0500, guynoir
wrote:

The side facing the pilot is the face. The side away from the pilot is the
back, unless you fly a pusher.

That terminology is as intuitively backwards as some of the computer
stuff I work with.

Just think of it as 'little endian' vs. 'big endian'. *GRIN*

It makes sense, if you think of it in terms of which 'side' of the prop is
doing the work. It's the one to the rear that actually pushes the air around.

Filing or dressing out prop nicks is a job for a licensed
mechanic, since there are legal specs that must be adhered to, and the
prop manufacturer has more dimensional limits that need to be checked.
They learned these things the hard way; don't you go doing the same.
The right sort of nick, in the right place, given enough time in
operation, will result in a crack that could see a chunk of prop
disappear, and the imbalance could tear the engine off the airplane.
The airplane will not glide with its engine missing, so nicks need to
be taken seriously.
I've seen some badly repaired nicks that actually make the
prop more likely to fail.
Dan

Do NOT try to dress out the prop yourself. Even a small nick can cause a
prop to fail in flight. If this happens at full power, the engine can be
ripped off the airplane in less than a second! Without the engine, the
airplane becomes extremely tail heavy and a violent crash is unavoidable.

Certain types of nicks on certain models or propellor are fixable. A
licensed mechanic with a powerplant rating knows how to properly dress a
prop if it's possible, and rebalance and repaint the prop. Don't try to
paint the prop yourself. Even a small amount of paint on one side can
seriously unbalance a prop. Some propellors are balanced by simply
applying varnish to one side...that's all it takes! Get a prop shop or a
powerplant mechanic to work on it.

wrote:
Filing or dressing out prop nicks is a job for a licensed
mechanic, since there are legal specs that must be adhered to, and the
prop manufacturer has more dimensional limits that need to be checked.
They learned these things the hard way; don't you go doing the same.
The right sort of nick, in the right place, given enough time in
operation, will result in a crack that could see a chunk of prop
disappear, and the imbalance could tear the engine off the airplane.
The airplane will not glide with its engine missing, so nicks need to
be taken seriously.
I've seen some badly repaired nicks that actually make the
prop more likely to fail.
Dan

Here's another perspective on blimps.

Interesting factoids from chief engineer: Fins are in 2 parts so they
fit easily into a standard container. They usually operate the blimp as
well as manufacture it. American Blimp in Hillsboro, OR has manufactured
80% of all blimps flying. American Blimp is manufacturing and operating
new blimps for Goodyear. All blimps currently flying have bullet holes
in them, and there is a standard, FAA approved bullet hole repair.
Pressure inside the envelope is a few inches of water, maintained by
either a duct collecting propwash or by electric fans at low power. It
costs $40,000US for the helium for each inflation, and it's not practical
to try and recycle the gas. The next project is to put those goddamned
annoying television billoards on their blimps. The blimps are called
"lightships" because the envelope is translucent, and they shine a couple
1000 watt light bulbs in it, so it glows in the dark. This means that
the evelope is also vulnerable to UV from the sun, which means that it
has to be replaced every few years.


"canflyboy" wrote in
:

Hi All

I'm repainting my McCauley Aluminium prop and was wondering if anyone
can give me some guidance in regards to the little aluminums dings
that occurred on the back side of the tip on the prop. These are tiny
dings the prop has picked up over the years from sucking up debris
while taxing. They vary from tiny pin pricks to small scratches,
maybe .015" at the deepest and maybe about .05" inches long.

I'm not sure if I should try and dress these out with a sander
(grinder) because to get them all out, I'd be taking off some serious
aluminium.

Any tips on sanding would be appreciated.

Thanks

Eugene





--
J Kimmel

www.metalinnovations.com

"Cuius testiculos habes, habeas cardia et cerebellum." - When you have
their full attention in your grip, their hearts and minds will follow.