Prop angle of attack vs age

Rich Ahrens wrote in news:48790786$0$60071
:

on 7/12/2008 1:39 PM Bertie the Bunyip said the following:
"Maxwell" luv2^fly99@cox.^net wrote in
:

"Bertie the Bunyip" wrote in message
...
You don't need those drugs, Maxie, you just need a bit of electro
shock. Try sticking your tongue in a light socket.
You'll not only enjoy it, you'll notice the difference n your outlook
in a matter of days, if not hours.


Bertie
Sounds like the voice of experience to me.

Now we know the rest of the story. Good day!

Awww, IKYABWAI lames.

You adorable!

You have quite the chewtoy there, Bertie! I think you can set the drag
on high with this one and he won't throw the hook.


Absolutely. You don't get one like this every day!

Bertie

"Bertie the Bunyip" wrote in message
...


Oh sorry, i thought you were talking about the improvements on the
tailwind. Never heard of anything like that before



Try to keep up dumb ass.

"Maxwell" luv2^fly99@cox.^net wrote in news:ADaek.20360$%q.1443
@newsfe24.lga:


"Bertie the Bunyip" wrote in message
...


Oh sorry, i thought you were talking about the improvements on the
tailwind. Never heard of anything like that before



Try to keep up dumb ass.




Do give us a dissertation on efficiency luser boi.



Bertie

On Sat, 12 Jul 2008 08:45:36 -0700 (PDT), More_Flaps
wrote:

On Jul 13, 12:53*am, wrote:
On Jul 12, 8:37*am, Stealth Pilot
wrote:



On Fri, 11 Jul 2008 06:00:22 -0700 (PDT), wrote:
On Jul 11, 7:09*am, Stealth Pilot
wrote:
On Fri, 11 Jul 2008 08:57:13 +0000 (UTC), Bertie the Bunyip
wrote:

sid wrote in news:702f8b8d-b77e-452c-904c-
:

On older planes, does the angle of attack change ? Does the prop angle
relax like a motorboat prop does after 1 or 2 decades of constant
use ? (fixed pitch of course)

There are some older warriors on the field (20 - 25) years, and it
seems that there props don't have the bite that the new warrior (10
years old) does.

No, but years of wear and dressing the prop because of nicks and what not
doesn't do them any good at all.

Bertie

I have a fibreglass covered wooden prop which makes it reasonably
resilient in light rain. I paint it.
when the aforesaid light rain has eroded the paint *near the leading
edge I lose 5 knots in cruise speed.

also If I alter the shape with a poor paint coat I lose cruise speed.

the other factor with some commercial aircraft is that there are often
3 props approved for them. a climb, a utility and a cruise prop.
on little cessnas they are each 2 inches of pitch apart.
memories of cruise with a cruise prop would make cruise on a climb
prop seem quite anaemic.

....and what bertie wrote.

Stealth Pilot

I can understand why a poor -- as in not smooth -- paint job would
alter the prop's efficiency, but never would have guessed having a
fractional mm of paint ablated from the leading edge of the prop would
affect it that much. Tongue in cheek question -- did the natural color
of the prop clash with that color and scare the air, or something?

On a serious note, have you any thoughts as to why such a minor change
in shape would have such a remarkable change in efficiency? A 5 knot
change in airspeed is like reducing the manifold an inch or so, isn't
it? That's huge! It also suggests there may be very minor changes in
prop that could improve performance too.

l

the prop had a fairly average sheath put on it. average workmanship.
I use the paint layers to fair the surface to a smoother shape.
the face I see is painted matte black to make it invisible.
the leading edge is blue, the rest varnish.
chipped paint just creates a turbulator which seems to affect this
blade section. (clark Y, aka naca 44xx series)

I got 5 extra knots in cruise for nothing when I cleaned up the prop
and got the shape right the first time. the damaged leading edge paint
just drops me back to the original slower cruise.

Stealth Pilot

Five knots is a huge gain. I remember reading some years ago of a
homebuilt getting a new paint job, and the color change on the wings
led to a paint 'bump' or seam near the leading edge which so altered
the airflow the airplane could not fly (probably changed the
stagnation line).

Sounds like a myth to me. How thick is a paint line?


not a myth at all. it was a well documented problem on one of the
early fibreglass canards. the addition of a decorative tape stripe on
the top of the canard resulted in the aircraft not being able to
takeoff. removal of the stripe fixed the problem.

in an allied situation a friend complained of a sudden 45 knot
reduction in the speed of his RV6. it really put the wind up him.
a cursory inspection and I could see that the heavyweight polyurethane
protective tape he'd applied to the prop had destroyed the aerofoil
shape. he removed it at my suggestion and immediately had his 45 knots
back.

remember being told to remove frost from the wings before flight?
more than one aircraft has crashed because they didnt.

same effect.

Stealth Pilot

On Sat, 12 Jul 2008 18:25:42 +0000 (UTC), Bertie the Bunyip
wrote:


I got 5 extra knots in cruise for nothing when I cleaned up the
prop and got the shape right the first time. the damaged leading
edge paint just drops me back to the original slower cruise.

Stealth Pilot

Five knots is a huge gain. I remember reading some years ago of a
homebuilt getting a new paint job, and the color change on the wings
led to a paint 'bump' or seam near the leading edge which so altered
the airflow the airplane could not fly (probably changed the
stagnation line).

Sounds like a myth to me. How thick is a paint line?

Still, that big a change in cruise speed seems
remarkable.

I'd say unlikely.

Not in an airplane like the Tailwind. A small change in somethign like a
Cherokee might not get you much, though a series of changes will get you
quite a lot evn in one of those, but something that acts more of a whole
like a talwind or a Midget mustang can be hugely affected by one single
ingredient being out.


Bertie

on an allied note there was a cherokee that had been flown up in the
North of Australia all it's life. every year to protect the aircraft
the owner had hand painted it. the paint eventually looked so crappy
that when it was sold the new owner immediately put it into the paint
shop.

the painters were intrigued by the thickness of the paint. on careful
examination made easier because each year it was painted a new colour
the painters discovered that it had 26 distinct layers of paint.
needless to say the professional paint job removed all of this re
alodined the skin and applied the thin paint coats.

the new owner reported that after repainting it felt like the aircraft
had an extra 50 horsepower.

paint matters.

Stealth Pilot

On Sat, 12 Jul 2008 13:41:49 -0500, "Maxwell" luv2^fly99@cox.^net
wrote:


"Bertie the Bunyip" wrote in message
.. .

Snort!

I'm so far ahead of you i know what you had for lunch next thursday.

It will be Spaghetti-ohs, BTW

Bertie

You're a legend in your own mind.


maxwell you are such a dimwit that if bertie was as thick as two short
planks he'd still be brilliant compared to you.
god you're a f@@@@@@t.

Stealth pilot

Stealth Pilot wrote in
:

On Sat, 12 Jul 2008 18:25:42 +0000 (UTC), Bertie the Bunyip
wrote:


I got 5 extra knots in cruise for nothing when I cleaned up the
prop and got the shape right the first time. the damaged leading
edge paint just drops me back to the original slower cruise.

Stealth Pilot

Five knots is a huge gain. I remember reading some years ago of a
homebuilt getting a new paint job, and the color change on the
wings
led to a paint 'bump' or seam near the leading edge which so
altered
the airflow the airplane could not fly (probably changed the
stagnation line).

Sounds like a myth to me. How thick is a paint line?

Still, that big a change in cruise speed seems
remarkable.

I'd say unlikely.

Not in an airplane like the Tailwind. A small change in somethign like
a
Cherokee might not get you much, though a series of changes will get
you
quite a lot evn in one of those, but something that acts more of a
whole
like a talwind or a Midget mustang can be hugely affected by one
single
ingredient being out.


Bertie

on an allied note there was a cherokee that had been flown up in the
North of Australia all it's life. every year to protect the aircraft
the owner had hand painted it. the paint eventually looked so crappy
that when it was sold the new owner immediately put it into the paint
shop.

the painters were intrigued by the thickness of the paint. on careful
examination made easier because each year it was painted a new colour
the painters discovered that it had 26 distinct layers of paint.
needless to say the professional paint job removed all of this re
alodined the skin and applied the thin paint coats.

the new owner reported that after repainting it felt like the aircraft
had an extra 50 horsepower.

paint matters.

On a prop, definitely. I'm sure the thing was getting a substantial
boost in HP if the revs were down static!

Bertie

Stealth Pilot wrote in
:

On Sat, 12 Jul 2008 08:45:36 -0700 (PDT), More_Flaps
wrote:

On Jul 13, 12:53*am, wrote:
On Jul 12, 8:37*am, Stealth Pilot
wrote:



On Fri, 11 Jul 2008 06:00:22 -0700 (PDT), wrote:
On Jul 11, 7:09*am, Stealth Pilot
wrote:
On Fri, 11 Jul 2008 08:57:13 +0000 (UTC), Bertie the Bunyip
wrote:

sid wrote in
news:702f8b8d-b77e-452c-904c-
:

On older planes, does the angle of attack change ? Does the
prop angle relax like a motorboat prop does after 1 or 2
decades of constant use ? (fixed pitch of course)

There are some older warriors on the field (20 - 25) years,
and it seems that there props don't have the bite that the
new warrior (10 years old) does.

No, but years of wear and dressing the prop because of nicks
and what not doesn't do them any good at all.

Bertie

I have a fibreglass covered wooden prop which makes it
reasonably resilient in light rain. I paint it.
when the aforesaid light rain has eroded the paint *near the
leading edge I lose 5 knots in cruise speed.

also If I alter the shape with a poor paint coat I lose cruise
speed.

the other factor with some commercial aircraft is that there
are often 3 props approved for them. a climb, a utility and a
cruise prop. on little cessnas they are each 2 inches of pitch
apart. memories of cruise with a cruise prop would make cruise
on a climb prop seem quite anaemic.

....and what bertie wrote.

Stealth Pilot

I can understand why a poor -- as in not smooth -- paint job
would alter the prop's efficiency, but never would have guessed
having a fractional mm of paint ablated from the leading edge of
the prop would affect it that much. Tongue in cheek question --
did the natural color of the prop clash with that color and scare
the air, or something?

On a serious note, have you any thoughts as to why such a minor
change in shape would have such a remarkable change in
efficiency? A 5 knot change in airspeed is like reducing the
manifold an inch or so, isn't it? That's huge! It also suggests
there may be very minor changes in prop that could improve
performance too.

l

the prop had a fairly average sheath put on it. average
workmanship. I use the paint layers to fair the surface to a
smoother shape. the face I see is painted matte black to make it
invisible. the leading edge is blue, the rest varnish.
chipped paint just creates a turbulator which seems to affect this
blade section. (clark Y, aka naca 44xx series)

I got 5 extra knots in cruise for nothing when I cleaned up the
prop and got the shape right the first time. the damaged leading
edge paint just drops me back to the original slower cruise.

Stealth Pilot

Five knots is a huge gain. I remember reading some years ago of a
homebuilt getting a new paint job, and the color change on the wings
led to a paint 'bump' or seam near the leading edge which so altered
the airflow the airplane could not fly (probably changed the
stagnation line).

Sounds like a myth to me. How thick is a paint line?


not a myth at all. it was a well documented problem on one of the
early fibreglass canards. the addition of a decorative tape stripe on
the top of the canard resulted in the aircraft not being able to
takeoff. removal of the stripe fixed the problem.


Yeah, I remember that. On the flip side of that the additin of a turbulator
strip in the right place will enhance lift..

http://www.standardcirrus.org/Turbulators.html


Bertie