Metal Prop vs. Wood Prop

Looking at the article, there is a sentence..."However, it also reduces the fatigue life by up to 50%." This is not the same as 1/2! It also doesn't attribute the numbers to Van. Read it carefully!

"Bob Kuykendall" wrote in message om...
Earlier, Ed Wischmeyer wrote:

what's the source that the anodized spars
have half the fatigue life? and why? Is
that true in general, or only for these
spars?

http://www.matronics.com/rv-list/hov...s/AlAnDef.html

Search this page on "Fatigue." It references a 1991 RVator article by Van:

http://www.matronics.com/rv-list/hov...s/AlAnDef.html

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com/hp-24

On Mon, 22 Sep 2003 06:46:10 -0700, Ed Wischmeyer
wrote:

If the anodised phlogiston spars (used
on RV's) have half the fatigue life of an alodined spar


My newsreader doesn't get all the messages, so I may have missed the
antecedent referenced -- but what's the source that the anodized spars
have half the fatigue life? and why? Is that true in general, or only
for these spars?

thanks

Ed Wischmeyer

Ed it is as the other guys have posted. I believe our CASA got the
fidgets with it as well but I forget the details.

btw I have retired from my high and lofty position :-)
I'm now just a regular weekend pilot and full time uni student (tisc,
at my age) for another 2 or so years.

accordingly ...no need to bow when we meet now. :-) :-)
Hope your work with the EAA continues to go well.
Stealth Pilot
Australia

On Sat, 20 Sep 2003 19:21:22 -0400, "Larry Smith"
wrote:

I have a wood prop on my Taylorcraft and the GPS says it's slow, at around
65 kts. How about a discussion on the relative merits of wood and aluminum
props. I understand that wood is easier on your engine but the aluminum
prop is more efficient. Another thing I notice too, especially on the
O-320 and O-360-powered RV's is that the wood prop is so light it has little
flywheel effect and if you don't have your timing retarded, it will kick
back in a heartbeat. I figure the wood prop on a Van's aircraft is for CG.

To retard the timing because of a wooden prop is nuts.
I've never met anyone dumb enough to even consider this.
YMMV.

FWIW....
My 0-320 with wooden prop would attempt to shake
the airframe and itself apart below 900 rpm.
So, you accept the 900 rpm idle.
That's it.
Period.

With metal prop --
Idle is acceptably smoooth, even at 650 rpm.
Added bonuses - brake life is increased.
No longer does the RV3 with 79 pitch attempt to taxi at 20+ mph.
Running in rain is a joy. No varnish to be damaged - unlike with wood.

I think what I'll do is buy an aluminum prop and try it for a while. I
couldn't keep up with a DCO-75 last week and it was a little embarrassing,
since his engine was sick. But he had an aluminum prop.

Sorry, there's more here than meets the casual eye.

A friend has two 65 hp T-Crafts with McCauley 45 pitch props.
Both run 90 mph at 2150 rpm.
Both will exceed 100 mph at WOT at 2000 ASL.

P.S.
Unless you look real close...
A metal prop pitched the same as a wood one
will cruise about the same. Not worth the money
difference in speed, if that is all you're looking for.

If you have to go significantly faster...
remove the wings or at least clip them
and bolt on a C-85.


Barnyard BOb --

"Barnyard BOb --" wrote in message
...
On Sat, 20 Sep 2003 19:21:22 -0400, "Larry Smith"
wrote:

I have a wood prop on my Taylorcraft and the GPS says it's slow, at
around
65 kts. How about a discussion on the relative merits of wood and
aluminum
props. I understand that wood is easier on your engine but the aluminum
prop is more efficient. Another thing I notice too, especially on the
O-320 and O-360-powered RV's is that the wood prop is so light it has
little
flywheel effect and if you don't have your timing retarded, it will kick
back in a heartbeat. I figure the wood prop on a Van's aircraft is for
CG.

To retard the timing because of a wooden prop is nuts.
I've never met anyone dumb enough to even consider this.
YMMV.

No flywheel effect with the lightweight prop. Add to that one of those
hot-spark electronic ignitions and you have the engine's flywheel and the
starter trying to tear each other up. Kickback. Never had it happen to
me but have seen it, so you are supposed to retard the timing, but just at
starting time, by starting on the mag, NOT on the Electroair. After she
begins running then you turn on the Electroair and everything is running at
advanced timing. And btw I recall reading that Klaus Savier (Lightspeed)
would advance his timing from the cockpit to as much as 45 degrees before
top dead center. During a race. At altitude. But not when starting.
ymmav.


FWIW....
My 0-320 with wooden prop would attempt to shake
the airframe and itself apart below 900 rpm.
So, you accept the 900 rpm idle.
That's it.
Period.

With metal prop --
Idle is acceptably smoooth, even at 650 rpm.
Added bonuses - brake life is increased.
No longer does the RV3 with 79 pitch attempt to taxi at 20+ mph.
Running in rain is a joy. No varnish to be damaged - unlike with wood.

I think what I'll do is buy an aluminum prop and try it for a while. I
couldn't keep up with a DCO-75 last week and it was a little
embarrassing,
since his engine was sick. But he had an aluminum prop.

Sorry, there's more here than meets the casual eye.

Yeah, and a sick engine will still run like a scalded dog. We had a
210-horse Continental once with compressions in the 30's and that thing was
a running piece of plunder.


A friend has two 65 hp T-Crafts

Selfish. He should share.

with McCauley 45 pitch props.
Both run 90 mph at 2150 rpm.
Both will exceed 100 mph at WOT at 2000 ASL.

I want that. Must try to achieve it. It may be necessary to do a little
rigging and clean things up a little. Your friend probably has his faired
in a little better than mine, wheel pants, that sort of thing, to make it
slicker, and you can take some of the twist out of the wings too. Makes
them squirrelly but faster. One benefit, though, is that if you take out
all the wash-out it doesn't turn to wash-in when you're flying inverted.


P.S.
Unless you look real close...
A metal prop pitched the same as a wood one
will cruise about the same. Not worth the money
difference in speed, if that is all you're looking for.

If you have to go significantly faster...
remove the wings

Like those turkey buzzards and redtails hereabouts which fold theirs up and
drop like bottle rockets when the Pud and I chase them?

or at least clip them
and bolt on a C-85.

That's an idea. Maybe another T-Craft like your friend. I already have
the C-85. It needs a top but the bottom is sound. I called Sensenich
about an aloonium* prop and they want 2600 bucks for one. So I'll look for
a used one.

Our clipwing expert in this neck of the woods, down in Mebane, builds his
wings with lightweight ply ribs and uses a hopped up O-200. I think he
calls it a Swick.


Barnyard BOb --














*Aside: This one should really get him hopping.

"Larry Smith" wrote:

I called Sensenich
about an aloonium* prop and they want 2600 bucks for one. So I'll look for
a used one.

*Aside: This one should really get him hopping.
++++++++++++++++++++++++++++++

Careful...
or I won't save you any money on a Sensenich prop.

You should be able to buy NEW for around $1800....
but not directly from Sensenich. They only give
10% discounts, AFAIK.

You wanna talk nice now and do a little HOPPING for me?
I have a dealer source that discounts Sensenich. If you talk
real nice I might even arrange a Sensenich T-shirt for your
smart ass.


Barnyard BOb -- a very satisfied Sensenich customer

"Barnyard BOb --" wrote in message
...

"Larry Smith" wrote:

I called Sensenich
about an aloonium* prop and they want 2600 bucks for one. So I'll look
for
a used one.

*Aside: This one should really get him hopping.
++++++++++++++++++++++++++++++

Careful...
or I won't save you any money on a Sensenich prop.

O, I'm in milquetoast mode from now on.


You should be able to buy NEW for around $1800....
but not directly from Sensenich. They only give
10% discounts, AFAIK.

Big difference. A Sen dealer in GA wanted $2525.

You wanna talk nice now and do a little HOPPING for me?
I have a dealer source that discounts Sensenich. If you talk
real nice I might even arrange a Sensenich T-shirt for your
smart ass.

Damn am I humble.


Barnyard BOb -- a very satisfied Sensenich customer

"Kyle Boatright" wrote in message
t...

"Larry Smith" wrote in message
...

"Barnyard BOb --" wrote in message
...
On Sat, 20 Sep 2003 19:21:22 -0400, "Larry Smith"
wrote:

I have a wood prop on my Taylorcraft and the GPS says it's slow, at
around
65 kts. How about a discussion on the relative merits of wood and
aluminum
props. I understand that wood is easier on your engine but the
aluminum
prop is more efficient. Another thing I notice too, especially on
the
O-320 and O-360-powered RV's is that the wood prop is so light it has
little
flywheel effect and if you don't have your timing retarded, it will
kick
back in a heartbeat. I figure the wood prop on a Van's aircraft is
for
CG.

To retard the timing because of a wooden prop is nuts.
I've never met anyone dumb enough to even consider this.
YMMV.

No flywheel effect with the lightweight prop. Add to that one of those
hot-spark electronic ignitions and you have the engine's flywheel and
the
starter trying to tear each other up. Kickback. Never had it happen
to
me but have seen it, so you are supposed to retard the timing, but just
at
starting time, by starting on the mag, NOT on the Electroair. After
she
begins running then you turn on the Electroair and everything is running
at
advanced timing. And btw I recall reading that Klaus Savier
(Lightspeed)
would advance his timing from the cockpit to as much as 45 degrees
before
top dead center. During a race. At altitude. But not when starting.
ymmav.


Larry,

The Electroair does retard the timing to 0 degrees BTDC below a threshold
RPM level. This prevents starting kick-back. I seem to remember the
advance
is at 0 until 300-400 rpm, but the manual is at the airport. Above that
level, the spark advances along a curve to the same setting you'd get from
a
mag.. That lasts until you reach an rpm/manifold pressure combination
that
is representative of a typical cruise power setting. At that time, the
timing follows another curve which advances the spark beyond what you
would
see from a mag. IIRC, the baseline setting is 17 degrees, and I've seen as
much as 40 degrees of advance at high altitude and low power settings.

BTW, my 0-320/wood prop RV-6 is happy to idle at 500-600 rpm with the
Electroair. The biggest downfall to any of these systems (lightspeed,
electroair, etc) is that the parts supply is very limited. If a component
fails, you may have to wait a while for a replacement, particularly if the
vendor is away from home. With a mag, you could have a dozen or more
suppliers ship you a new one in 24 hours. Helps a lot if you break
something while away from home...

KB

Thanks for the correction, Kyle, and for your excellent testimonial. It's
been some time since I saw a broken starter shaft and cogs stripped out of a
flywheel from kickback at starting. One of those hot-spark ignition
systems had been blamed. Everybody here in WNC likes Jeff Rose's ignition.
And besides that, we just nacherly gravitate towards Chattanooga folks.
They is down home.

I'm about to be looking for a hot-sparker for a six-banger.

"Larry Smith"

Careful...
or I won't save you any money on a Sensenich prop.

O, I'm in milquetoast mode from now on.

I guess MONEY really does talk, eh? g

You should be able to buy NEW for around $1800....
but not directly from Sensenich. They only give
10% discounts, AFAIK.

Big difference. A Sen dealer in GA wanted $2525.

For your T-Craft...
http://www2.sensenich.com/direct/tcraft.htm

You want this TexASS dealer....

Stan Shannon --
http://www.kitplaneparts.com/

Psssst.
Do NOT mention my name.
Chances are you will get a better deal if you don't.
Honest.
I can explain, but not here.

You wanna talk nice now and do a little HOPPING for me?
I have a dealer source that discounts Sensenich. If you talk
real nice I might even arrange a Sensenich T-shirt for your
smart ass.

Damn am I humble.

If you actually order a new Sensenich prop....
I GUARANTEE you a T-Shirt from the Lititz PA factory.

I will need your name address, etcetera..
if things work out.


Barnyard BOb --

"Barnyard BOb --" wrote in message
...

"Larry Smith"

Careful...
or I won't save you any money on a Sensenich prop.

O, I'm in milquetoast mode from now on.

I guess MONEY really does talk, eh? g

You should be able to buy NEW for around $1800....
but not directly from Sensenich. They only give
10% discounts, AFAIK.

Big difference. A Sen dealer in GA wanted $2525.

For your T-Craft...
http://www2.sensenich.com/direct/tcraft.htm

You want this TexASS dealer....

Stan Shannon --
http://www.kitplaneparts.com/

Psssst.
Do NOT mention my name.
Chances are you will get a better deal if you don't.
Honest.
I can explain, but not here.

Thanks, Bob. I preshate it.

You wanna talk nice now and do a little HOPPING for me?
I have a dealer source that discounts Sensenich. If you talk
real nice I might even arrange a Sensenich T-shirt for your
smart ass.

Damn am I humble.

If you actually order a new Sensenich prop....
I GUARANTEE you a T-Shirt from the Lititz PA factory.

I will need your name address, etcetera..
if things work out.


Barnyard BOb --

"Larry Smith" wrote:

You should be able to buy NEW for around $1800....
but not directly from Sensenich. They only give
10% discounts, AFAIK.

Big difference. A Sen dealer in GA wanted $2525.

For your T-Craft...
http://www2.sensenich.com/direct/tcraft.htm

You want this TexASS dealer....

Stan Shannon --
http://www.kitplaneparts.com/

Psssst.
Do NOT mention my name.
Chances are you will get a better deal if you don't.
Honest.
I can explain, but not here.

Thanks, Bob. I preshate it.
++++++++++++++++++++++++++++++

You're quite welcome.

My hope is that you can get a new metal prop
for LESS than $1800. I know it is do-able.
However, second guessing Stan isn't smart.
He's another one of them... old pharts. g


Barnyard BOb -- youthful senior citizen