I'm trying to select a suitable spinner for our Rans S6S. Besides looks,
weight and airflow I'm a bit worried about safety. There are several options
in terms of material and mechanical construction, and I'd like to hear what
experience you have with any particular type. One thing I'm wondering about
is that many spinner backplates are sandwitched between the propeller hub
and the propeller itself.

I read somewhere that the power transfer to the prop works by means of
friction between prop and hub. The prop bushings are only there to center
the prop. If that is correct then introducing an extra layer between the
prop and the hub can have profound impact on power transfer. Unfortunately
I've been unable to find any documentation on this subject at all.

Any thoughts??

Rob

On Mar 29, 3:47 am, "Rob Turk" > wrote:
> I'm trying to select a suitable spinner for our Rans S6S. Besides looks,
> weight and airflow I'm a bit worried about safety. There are several options
> in terms of material and mechanical construction, and I'd like to hear what
> experience you have with any particular type. One thing I'm wondering about
> is that many spinner backplates are sandwitched between the propeller hub
> and the propeller itself.
>
> I read somewhere that the power transfer to the prop works by means of
> friction between prop and hub. The prop bushings are only there to center
> the prop. If that is correct then introducing an extra layer between the
> prop and the hub can have profound impact on power transfer. Unfortunately
> I've been unable to find any documentation on this subject at all.
>
> Any thoughts??
>
> Rob

I've been running fiberglass spinners with carbon fiber backplates on
Rotax engines (2 and 4 cycle) for years with no problems. 2 Rans
S-6's, both with 912s had this setup. The only problem I ever had
with a spinner was an aluminum one on a 2 cycle rotax engine powered
airplane.

I am presently running a fiberglass spinner with a carbon backplate on
my Long-EZ with a 175hp engine. No problems there either.

Rick Pellicciotti
Belle Aire Aviation, Inc.
http://www.belleaireaviation.com

Sensenich addresses this matter in the installation and maintenance
instructions for their wooden propellers:

http://www.sensenichprop.com/sen_html/aircraft_cet/install/cf-a.pdf

(Note that it's a PDF file; make sure your browser is set to accept
PDF downloads.) In Step 2 of the installation procedure they indicate
that the rear spinner-bulkhead may be either ahead of or behind the
prop-to-engine plate. But they also specify that all contact surfaces
in the sandwich be cleaned with alcohol and a fine Scotchbrite pad.
Apparently as long as the surfaces are clean and bone-dry they'll
develop the necessary friction at all the interfaces.

On Mar 29, 2:47 am, "Rob Turk" > wrote:
> I'm trying to select a suitable spinner for our Rans S6S. Besides looks,
> weight and airflow I'm a bit worried about safety. There are several options
> in terms of material and mechanical construction, and I'd like to hear what
> experience you have with any particular type. One thing I'm wondering about
> is that many spinner backplates are sandwitched between the propeller hub
> and the propeller itself.
>
> I read somewhere that the power transfer to the prop works by means of
> friction between prop and hub. The prop bushings are only there to center
> the prop. If that is correct then introducing an extra layer between the
> prop and the hub can have profound impact on power transfer. Unfortunately
> I've been unable to find any documentation on this subject at all.
>
> Any thoughts??
>
> Rob

I have been running the spinners that Vans sells on my V-8 powered
Zenith 801. I have one cut for a two blade and the one thats on there
now is a three blade set up, The spinner is a greenish color, maybe a
kevlar material. They are very well made and reasonably priced. My
thoughts on the attach concept is this. The prop is attached to the
crank hub by six bolts, when they are torqued properly they are in
shear and tension and holding the prop tightly against the hub. That
is the friction aspect of the concept. The bushing do align the prop
to the hub, they also are in shear as they prevent the prop from
spinning on the hub. A metal prop has the abilty to absorb this as the
material is harder then say a wooden or composite prop. If those were
to rely on that only, the counterbores in those props that the bushing
sits in will quickly distort. So, my take on this is, The prop bolts
when torqued are carrying 80% of the load, the surface friction is
carrying the rest. Warning,,,,,, I didn't stay in a Holiday Inn
Express last night either so you mileage my vary....

Ben
www.haaspowerair.com

Ben Haas wrote:

> Rob Turk wrote:
>> I read somewhere that the power transfer to the prop works by
>> means of friction between prop and hub. The prop bushings are
>> only there to center the prop. If that is correct then
>> introducing an extra layer between the prop and the hub can have
>> profound impact on power transfer.

> .... So, my take on this is, The prop bolts when torqued are
> carrying 80% of the load, the surface friction is carrying the
> rest.

For WOODEN props, or wood core/composite wrap props (basically,
anything with a predominantly wooden hub), Rob is correct - the
friction between the face of the propeller and the face of the prop
extension (or hub) transmits 100% of the torque from the engine to the
propeller. The bushings do NOT transfer any force to the propeller,
and the bolts most certainly do not transfer any load to the prop and
are NOT loaded in shear.

The prop bolts are in tension (about 3000 -4000 lb on a 1/2 in. bolt),
and are there ONLY to ensure that there's enough force on the
propeller/hub interface to create the friction necessary to drive the
prop. About 600 psi is required - much less than that leads to
slippage, and more than that can crush the prop.

WRT backing plates, there are those who believe that the plate CAN
affect the transfer of torque between the hub and the prop. The
material of the backing plate may matter. From the standpoint of
friction, aluminum should be fine - that's what the hub's made of.

Personally, I think that a composite backing plate, with low
temperature epoxy, could be an issue, but ONLY if the bolts aren't
torqued correctly and/or the prop starts slipping and heats up the
backing plate, softening the epoxy more.


For visuals on what can happen when you don't torque your prop bolts
correctly on a wooden prop, see:

http://www.cozybuilders.org/Desert_Center/index.html

I need to update the web pages - I've now got all six bolts using
bellevilles.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2007

On Mar 30, 8:32 pm, "Marc J. Zeitlin" >
wrote:
> Ben Haas wrote:
> > Rob Turk wrote:
> >> I read somewhere that the power transfer to the prop works by
> >> means of friction between prop and hub. The prop bushings are
> >> only there to center the prop. If that is correct then
> >> introducing an extra layer between the prop and the hub can have
> >> profound impact on power transfer.
> > .... So, my take on this is, The prop bolts when torqued are
> > carrying 80% of the load, the surface friction is carrying the
> > rest.
>
> For WOODEN props, or wood core/composite wrap props (basically,
> anything with a predominantly wooden hub), Rob is correct - the
> friction between the face of the propeller and the face of the prop
> extension (or hub) transmits 100% of the torque from the engine to the
> propeller. The bushings do NOT transfer any force to the propeller,
> and the bolts most certainly do not transfer any load to the prop and
> are NOT loaded in shear.
>
> The prop bolts are in tension (about 3000 -4000 lb on a 1/2 in. bolt),
> and are there ONLY to ensure that there's enough force on the
> propeller/hub interface to create the friction necessary to drive the
> prop. About 600 psi is required - much less than that leads to
> slippage, and more than that can crush the prop.
>
> WRT backing plates, there are those who believe that the plate CAN
> affect the transfer of torque between the hub and the prop. The
> material of the backing plate may matter. From the standpoint of
> friction, aluminum should be fine - that's what the hub's made of.
>
> Personally, I think that a composite backing plate, with low
> temperature epoxy, could be an issue, but ONLY if the bolts aren't
> torqued correctly and/or the prop starts slipping and heats up the
> backing plate, softening the epoxy more.
>
> For visuals on what can happen when you don't torque your prop bolts
> correctly on a wooden prop, see:
>
> http://www.cozybuilders.org/Desert_Center/index.html
>
> I need to update the web pages - I've now got all six bolts using
> bellevilles.
>
> --
> Marc J. Zeitlin
> http://www.cozybuilders.org/
> Copyright (c) 2007

So, using your idea I can remove my 6 1/2" prop bolts and all the
bushings and replace the prop bolts with 6 3/16" or 1/4" bolts. The
total force applied with 6 of those small bolts torqued will exceed
the 600 lbs. You claim all I need 600 lbs of clamping force against
the crank hub to prevent the prop from spinning. This might work on a
model plane but I would NEVER try it on my plane. IMHO..

stol wrote:

> So, using your idea I can remove my 6 1/2" prop bolts and all the
> bushings and replace the prop bolts with 6 3/16" or 1/4" bolts.

Where did you get the idea that I said that?

> ... The
> total force applied with 6 of those small bolts torqued will exceed
> the 600 lbs. You claim all I need 600 lbs of clamping force against
> the crank hub to prevent the prop from spinning.

Read my previous message again, please. I said, pretty explicitly,
that you need about 600 psi between the prop and the hub, not 600 lb.
PSI stands for "lb/sq. in.". For a 30 square inch area prop hub
(about the area of an SAE-2 hub), that works out to about 18,000 lb.
of force, total. That's where the 3,000 lb/bolt that I mentioned came
from.

> .... This might work on a
> model plane but I would NEVER try it on my plane. IMHO..

Actually, as it turns out, since each of the six bolts holding the
wooden propeller on must have about 3-4K lb of force on it (with an
SAE-2 flange), and a 1/4" AN bolt (~.036 sq-in cross section in the
threads) can withstand about 125K psi before breaking, the stress of
~110 ksi on the bolt would still put it below it's ultimate strength,
although probably higher than it's yield strength.

So, 3/16" bolts wouldn't work, but 1/4" bolts could possibly work, in
certain circumstances, like on SAE-1 flanges, which require less force
(being smaller) to create the same 600 psi.

In fact, Jabiru uses 1/4" bolts to hold their props on some of their
engines, and also uses belleville washers.

Learn something new every day, huh?

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2007

On Mar 31, 12:24 am, "Marc J. Zeitlin" >
wrote:
> stol wrote:
> > So, using your idea I can remove my 6 1/2" prop bolts and all the
> > bushings and replace the prop bolts with 6 3/16" or 1/4" bolts.
>
> Where did you get the idea that I said that?
>
> > ... The
> > total force applied with 6 of those small bolts torqued will exceed
> > the 600 lbs. You claim all I need 600 lbs of clamping force against
> > the crank hub to prevent the prop from spinning.
>
> Read my previous message again, please. I said, pretty explicitly,
> that you need about 600 psi between the prop and the hub, not 600 lb.
> PSI stands for "lb/sq. in.". For a 30 square inch area prop hub
> (about the area of an SAE-2 hub), that works out to about 18,000 lb.
> of force, total. That's where the 3,000 lb/bolt that I mentioned came
> from.
>
> > .... This might work on a
> > model plane but I would NEVER try it on my plane. IMHO..
>
> Actually, as it turns out, since each of the six bolts holding the
> wooden propeller on must have about 3-4K lb of force on it (with an
> SAE-2 flange), and a 1/4" AN bolt (~.036 sq-in cross section in the
> threads) can withstand about 125K psi before breaking, the stress of
> ~110 ksi on the bolt would still put it below it's ultimate strength,
> although probably higher than it's yield strength.
>
> So, 3/16" bolts wouldn't work, but 1/4" bolts could possibly work, in
> certain circumstances, like on SAE-1 flanges, which require less force
> (being smaller) to create the same 600 psi.
>
> In fact, Jabiru uses 1/4" bolts to hold their props on some of their
> engines, and also uses belleville washers.
>
> Learn something new every day, huh?
>
> --
> Marc J. Zeitlin
> http://www.cozybuilders.org/
> Copyright (c) 2007

I see you have the .edu in your email address so you must be a teacher
or professor. Now tell me how you came up with 30 square inches of
surface area on a a SAE-2 crank hub...Thanks in advance.

Ben

Is there any particular reason for using six bellevilles? Are they stacked
parallel? I read the whole story about the Cozy that threw a prop and
checked out the graphical data piece and think I understand why the
bellevilles are better than conventional. Due to the fact that a belleville
is a spring, if the prop hub shrinks or expands, the belleville acts as a
buffer. Yes?

I have a wooden prop, not yet installed and a sudden departure due to
improper torque is not a pleasant thought. If possible I'd like more
specific installation recommendations.

Ebby


"Marc J. Zeitlin" > wrote in message
...
> stol wrote:
>
>> So, using your idea I can remove my 6 1/2" prop bolts and all the
>> bushings and replace the prop bolts with 6 3/16" or 1/4" bolts.
>
> Where did you get the idea that I said that?
>
>> ... The
>> total force applied with 6 of those small bolts torqued will exceed
>> the 600 lbs. You claim all I need 600 lbs of clamping force against
>> the crank hub to prevent the prop from spinning.
>
> Read my previous message again, please. I said, pretty explicitly, that
> you need about 600 psi between the prop and the hub, not 600 lb. PSI
> stands for "lb/sq. in.". For a 30 square inch area prop hub (about the
> area of an SAE-2 hub), that works out to about 18,000 lb. of force, total.
> That's where the 3,000 lb/bolt that I mentioned came from.
>
>> .... This might work on a
>> model plane but I would NEVER try it on my plane. IMHO..
>
> Actually, as it turns out, since each of the six bolts holding the wooden
> propeller on must have about 3-4K lb of force on it (with an SAE-2
> flange), and a 1/4" AN bolt (~.036 sq-in cross section in the threads) can
> withstand about 125K psi before breaking, the stress of ~110 ksi on the
> bolt would still put it below it's ultimate strength, although probably
> higher than it's yield strength.
>
> So, 3/16" bolts wouldn't work, but 1/4" bolts could possibly work, in
> certain circumstances, like on SAE-1 flanges, which require less force
> (being smaller) to create the same 600 psi.
>
> In fact, Jabiru uses 1/4" bolts to hold their props on some of their
> engines, and also uses belleville washers.
>
> Learn something new every day, huh?
>
> --
> Marc J. Zeitlin
> http://www.cozybuilders.org/
> Copyright (c) 2007

stol wrote:

> I see you have the .edu in your email address so you must be a teacher
> or professor.

Nope. I'm an aeronautical engineer, and I work for Scaled Composites.
Does that somehow change the facts of the matter?

> ... Now tell me how you came up with 30 square inches of
> surface area on a a SAE-2 crank hub...Thanks in advance.

Math. My prop extension is about 7" in diameter. If I subtract the
area of the large hole in the center and the small holes for the
bolts, I get about 30 square inches.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2007

Ebby wrote:
> Is there any particular reason for using six bellevilles?

I wanted to ensure that I had more than enough deflection capability.
Probably 4, or even 2, would be adequate protection.

> ... Are they stacked parallel?

No, series. I wanted more deflection with the same force.

> ... I read the whole story about the Cozy that threw a prop and
> checked out the graphical data piece and think I understand why the
> bellevilles are better than conventional. Due to the fact that a
> belleville is a spring, if the prop hub shrinks or expands, the
> belleville acts as a buffer. Yes?

Exactly.

> I have a wooden prop, not yet installed and a sudden departure due
> to improper torque is not a pleasant thought. If possible I'd like
> more specific installation recommendations.

I'm in the process of writing an article for as yet unnamed
magazine(s) about this, and I'll be presenting a summary of the
article as part of the COZY forum at Oshkosh. I don't have enough
time on the installation yet (due to ignition problems, right now) to
make recommendations to other folks - I want to get at least 25 - 50
hours on the system before telling other folks exactly what I did and
what to use.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2007

Ebby wrote:
> Is there any particular reason for using six bellevilles? Are they stacked
> parallel? I read the whole story about the Cozy that threw a prop and
> checked out the graphical data piece and think I understand why the
> bellevilles are better than conventional. Due to the fact that a belleville
> is a spring, if the prop hub shrinks or expands, the belleville acts as a
> buffer. Yes?
>

With any spring, you have a 'spring rate' and a 'maximum deflection'.
Those who really know what they're talking about probably use different
terms, but you get the idea. The rate is how much the pressure
increases with each increment of deflection. Maximum deflection is the
range from no pressure to completely squashed.

The goal is to have some reasonable range of deflection, then obtain the
pressure you want somewhere in the middle of the range. Like you said,
the spring is a buffer, filling in when the wood shrinks, and giving
back a little when it expands. Spoon the belville washers together, ie
(()), and you increase the rate, takes more pressure to crush them. Put
them to back-to back, ie ()(), and you increase the maximum deflection.
You have twice as far to travel, but you don't really have to apply
any more force.

From that point, it's a mix'n'match game to get the characteristics you
want. Pick a washer, and get its nominal spring rate that'll be
specified by the manufacturer. Calculate how much pressure it'll apply
at half its max deflection. Calculate how many you'll need to get that
magical 600 PSI at the prop flange. Now how much will the prop hub
shrink and expand. The flange pressure drops with shrinkage, and
increases with expansion. You don't want to much pressure or to little,
so calculate what the pressure the belville will apply at the bottom and
top of the prop expansion range. Add a ()-belville pair, and you cut
down on for each pair. They share the prop hub expansion. Now the
pressure range they provide doesn't vary as much. Keep adding pairs
till the pressure will remain within comfortable limits.

On Mar 31, 9:59 am, "Marc J. Zeitlin" >
wrote:
> stol wrote:
> > I see you have the .edu in your email address so you must be a teacher
> > or professor.
>
> Nope. I'm an aeronautical engineer, and I work for Scaled Composites.
> Does that somehow change the facts of the matter?
>
> > ... Now tell me how you came up with 30 square inches of
> > surface area on a a SAE-2 crank hub...Thanks in advance.
>
> Math. My prop extension is about 7" in diameter. If I subtract the
> area of the large hole in the center and the small holes for the
> bolts, I get about 30 square inches.
>
> --
> Marc J. Zeitlin
> http://www.cozybuilders.org/
> Copyright (c) 2007

Sorry. My SAE #2 hub must be different then yours.

My math shows: and my plane has on it...................

6.0000" od
2.2500" id
6 holes@ 33/64

total square inches of surface is 23.048467

Now. since the bushing are not in shear and carrying any load I will
remove them to save some weight, so that opens up the six holes to .
625.

So my new surface area is now 22.457533 square inches.

When I grow up I wanna be a aeronautical engineer too.

stol wrote:

> Sorry. My SAE #2 hub must be different then yours.

Probably not. As I said, MY PROP EXTENSION has a 7" diameter. Very
likely, the SAE-2 hub is identical.

But my prop is on my extension, so the area of the extension is what I
use.

> total square inches of surface is 23.048467

Good. For your plane, with your setup, with a wood prop mounted
directly to the SAE-2 hub, 600 psi will get you about 13,800 lb total,
or about 2300 lb/bolt.

Now you know what you're shooting for.

> Now. since the bushing are not in shear and carrying any load I will
> remove them to save some weight, so that opens up the six holes to .
> 625.

Removing the bushings, which are used for ensuring alignment of the
prop during installation, will make aligning and balancing the prop
difficult, not to mention leaving you with nothing to screw the bolts
into (assuming that your bushings are threaded). Plus, you'd be out
of luck if you ever want to use a metal prop.

> So my new surface area is now 22.457533 square inches.

BFD.

> When I grow up I wanna be a aeronautical engineer too.

Not very likely, with your attitude.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2007

Marc,

Thanks for the additional info. Please keep me in the loop on your progress
regarding test results. I am a long way off from installing the propeller.
So patience is mandated at this point. I read the installation manual from
Sensenich and it seems straight forward yet the climate I live in the
humidity can get very low in the winter and extreme in the summer so I am
thinking the wooden prop will be shrinking and expanding with the seasons.
I think the bellevilles would be a suitable method of "auto adjustment" as
the seasons change. I could go with a metal prop but think the biplane will
look more authentic with wood.

Ebby


"Marc J. Zeitlin" > wrote in message
...
> Ebby wrote:
>> Is there any particular reason for using six bellevilles?
>
> I wanted to ensure that I had more than enough deflection capability.
> Probably 4, or even 2, would be adequate protection.
>
>> ... Are they stacked parallel?
>
> No, series. I wanted more deflection with the same force.
>
>> ... I read the whole story about the Cozy that threw a prop and checked
>> out the graphical data piece and think I understand why the
>> bellevilles are better than conventional. Due to the fact that a
>> belleville is a spring, if the prop hub shrinks or expands, the
>> belleville acts as a buffer. Yes?
>
> Exactly.
>
>> I have a wooden prop, not yet installed and a sudden departure due
>> to improper torque is not a pleasant thought. If possible I'd like
>> more specific installation recommendations.
>
> I'm in the process of writing an article for as yet unnamed
> magazine(s) about this, and I'll be presenting a summary of the
> article as part of the COZY forum at Oshkosh. I don't have enough
> time on the installation yet (due to ignition problems, right now) to
> make recommendations to other folks - I want to get at least 25 - 50
> hours on the system before telling other folks exactly what I did and
> what to use.
>
> --
> Marc J. Zeitlin
> http://www.cozybuilders.org/
> Copyright (c) 2007

Ebby wrote:

> Thanks for the additional info. Please keep me in the loop on your
> progress regarding test results.

Check the web pages on occasion, and feel free to ping me via email
for updates.

> .... the climate I live in the humidity can get very low in the
> winter and extreme in the summer so I am thinking the wooden prop
> will be shrinking and expanding with the seasons.

Absolutely. All the wood prop MFG's say to check the prop bolt torque
every 25 hours or so, AND when moving either way between a dry climate
and wet climate. Moving from MA to CA is what got me - I didn't check
the prop often enough (or correctly).

> I think the bellevilles would be a suitable method of "auto
> adjustment" as the seasons change.

Yes, I'm hoping to be able to come up with a generic formula that will
allow folks to plug in their hub size, bolt size and hub thickness,
and will spit out what washers to use and how many.

We'll see how it goes. Hopefully by OSH I'll have everything
determined, tested, and written.

> ... I could go with a metal prop but think the biplane will look
> more authentic with wood.

Plus weigh less :-).

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2007

On Mar 31, 2:16 pm, "Marc J. Zeitlin" >
wrote:
> stol wrote:
> > Sorry. My SAE #2 hub must be different then yours.
>
> Probably not. As I said, MY PROP EXTENSION has a 7" diameter. Very
> likely, the SAE-2 hub is identical.
>
> But my prop is on my extension, so the area of the extension is what I
> use.
>
> > total square inches of surface is 23.048467
>
> Good. For your plane, with your setup, with a wood prop mounted
> directly to the SAE-2 hub, 600 psi will get you about 13,800 lb total,
> or about 2300 lb/bolt.
>
> Now you know what you're shooting for.
>
> > Now. since the bushing are not in shear and carrying any load I will
> > remove them to save some weight, so that opens up the six holes to .
> > 625.
>
> Removing the bushings, which are used for ensuring alignment of the
> prop during installation, will make aligning and balancing the prop
> difficult, not to mention leaving you with nothing to screw the bolts
> into (assuming that your bushings are threaded). Plus, you'd be out
> of luck if you ever want to use a metal prop.
>
> > So my new surface area is now 22.457533 square inches.
>
> BFD.
>
> > When I grow up I wanna be a aeronautical engineer too.
>
> Not very likely, with your attitude.
>
> --
> Marc J. Zeitlin
> http://www.cozybuilders.org/
> Copyright (c) 2007

Just few few comments for you.

1- Bushings are also called Drive Lugs, if those are not in shear
then you are not a very good aeronautical engineer.

2- The reason stated I was going to replace my 1/2" prop bolts with
smaller diameter ones was to drive home the point that the bolts can
also be in shear too. If you don't comprehend that then you are not a
very good aeronautical engineer.

3- For centuries all aviatiors knew that wooden props swell and shrink
and a smart pilot/engineer would check the torque to maintain the
CORRECT setting.

4- After reading this post several things are obvious.

You are the idiot that forgot/ neglected to perform the proper torque
and you crashed your plane because of it.

For weeks you can't seem to get your ignition to fire properly. Come
on buddy, I have 8 cylinders and I get them to fire perfectly every
time and on BOTH ignition systems. I ain't even a aeronautical
engineer and as reported earlier I didn't stay at a Holiday Inn last
night either. As you should know your idea for the" spring nuts" to
keep the prop properly torqued is a good concept but flawed. All steel
will lose its spring value over time and your torque WILL default to
the loose side over time. Can you calculate that value safely??? I
bet not. I have spent several thousand hours building my experimental
plane and I engineered my firewall forward installation myself. To
have some schmuck that has crashed his plane because he was too f
_ckin lazy to check the torque on his prop talk down to me is the
ironic thing. Now that you have stated you moved from Ma to California
it is crystal clear that is the land of "fruit and nuts" and you are
the poster child.

I am going flying in a few hours in my plane, you, on the other hand
are going to be standing there,playing with yourself and trying to
get four cylinders to fire properly. In closing, your previous
question" Did ya learn something today" . You bet, if someone claims
to be an aeronautical engineer, run, don't walk away from him/her
because sooner or later they will kill themselves because of their
idiotic attitude.

Seeya Marc....................................

Ben
www.haaspowerair.com

"stol" > wrote a bunch of oter crap like this:

> 1- Bushings are also called Drive Lugs, if those are not in shear
> then you are not a very good aeronautical engineer.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

What's your problem, Ben? I've always been on your side, but right now, you
are acting like a jerk.

You don't need to tear someone down, to be the big man. Let it go.

It is possible that this guy has his expertise in other areas than small
single engine piston airplanes. He also has other things to do, (like a
job) and that might actually get in the way of getting his ignition fixed.

In fact, I would think it is probable. He is, after all, one of the people
responsible for building Spaceship One and putting it into space, and the
record books.

When you do something that can top that, come back and crow about it. Right
now, you need to grow up, because you are definitely not coming off as the
bigger man.
--
Jim in NC

On Apr 1, 6:14 am, "Morgans" > wrote:
> "stol" > wrote a bunch of oter crap like this:
>
> > 1- Bushings are also called Drive Lugs, if those are not in shear
> > then you are not a very good aeronautical engineer.
>
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> What's your problem, Ben? I've always been on your side, but right now, you
> are acting like a jerk.
>
> You don't need to tear someone down, to be the big man. Let it go.
>
> It is possible that this guy has his expertise in other areas than small
> single engine piston airplanes. He also has other things to do, (like a
> job) and that might actually get in the way of getting his ignition fixed.
>
> In fact, I would think it is probable. He is, after all, one of the people
> responsible for building Spaceship One and putting it into space, and the
> record books.
>
> When you do something that can top that, come back and crow about it. Right
> now, you need to grow up, because you are definitely not coming off as the
> bigger man.
> --
> Jim in NC

After sleeping on this and listening to Jim ,who's comments I have
read for years and respected I agree I went way too far. It is my Type
A personality that probably drives me. Also the years of competition
as a driver has formed my actions of taking no prisoners. On the track
it's either them or me to the finish line first and I will work to be
a better human. After all one day I will come face to face to Marc and
I respect the fact he is a fellow experimantal aircraft builder and
would like to debate him in a calm way.. As for Spaceship one,,,, my
take is those guys will make NASA obsolete and stand aviation on its
ear. You guys rock.....And thanks Jim for pointing out my bad
attitude...

Peace to all... aand mostly to you Marc..

Ben.

Ps. As for the Steven. P Mc Nicoll thing I will have a harder time
resolving that issue. <G>

stol wrote:

> 1- Bushings are also called Drive Lugs, if those are not in shear
> then you are not a very good aeronautical engineer.

With metal props, the drive lugs are in shear. With wooden props,
with the friction force providing 100% of the drive force, they are
not in shear. Ask any of the wood prop manufacturers if you don't want
to believe me - Sensenich, Hertzler, Catto, etc. Sensenich's
documentation says as much.

> 2- The reason stated I was going to replace my 1/2" prop bolts with
> smaller diameter ones was to drive home the point that the bolts
> can also be in shear too. If you don't comprehend that then you are
> not a very good aeronautical engineer.

If the bolts are in shear, you're in big trouble, as I found out. With
wooden props, the bolts are their to ensure the compression force, NOT
to act as shear members. Again, the prop manufacturers will bear this
out. Even in metal props, the bolts are NOT in shear - the drive lugs
are.

> 3- For centuries all aviatiors knew that wooden props swell and
> shrink and a smart pilot/engineer would check the torque to
> maintain the CORRECT setting.

Centuries?

Having admitted that it was MY fault that I didn't check the prop bolt
torque often enough (or correctly), you're hardly telling me something
I don't know. I guess, however, that since Dick Rutan lost his
propeller twice, he's not smart either, eh? I'm not the first person
to lose a prop, but I hope to lessen the frequency by doing this
testing and publicizing it.

People screw up on occasion. At least I'm big enough to admit my
screw-up in public, so that others can learn from it rather than
trying to hide it and be defensive.

> You are the idiot that forgot/ neglected to perform the proper
> torque..

See above.

> and you crashed your plane because of it.

I hardly call a safe landing at a paved airport a crash. It wasn't
even an incident, much less an accident or crash.

> For weeks you can't seem to get your ignition to fire properly.

What are you talking about?

> ... As you should know your idea for the" spring nuts" to keep the
> prop properly torqued is a good concept but flawed. All steel will
> lose its spring value over time and your torque WILL default to the
> loose side over time.

While steel does "creep", the "spring value" you refer to is called
Young's Modulus, and it does NOT change over time. Creeping is a form
of plastic deformation, and is, in fact, well understood in steel.

> .... Can you calculate that value safely???

Yes, actually, if you know the type of steel, the stress it's under,
and the temperature, you can easily calculate the amount of creep
(strain) that will occur over time. At the temperatures and stress
levels that these bellvilles will see, the strain is microscopic over
the lifetime of the washers/aircraft. It's also fairly simple, with a
go-no go gauge to determine whether or not the bellevilles have
retained their compressive force.

> ... I bet not.

How much?

I suppose you're going to tell me that the other folks (such as
Jabiru) that are using this technique (and there are many others that
have done so over the past 60 years) are also all idiots, and that it
hasn't ever worked for any of them, no matter what the evidence shows.

> I am going flying in a few hours in my plane, you, on the other
> hand are going to be standing there,playing with yourself and
> trying to get four cylinders to fire properly.

Funny you should mention that. I have over 466 hours on my aircraft
over the past 4.5 years. I've flown it all over the USA, and average
over 100 hours/year on an aircraft that cruises at over 200 mph. The
plane is flying well and safely, and I rarely play with myself while
working on the engine.

> ... In closing, your previous question" Did ya learn something
> today" . You bet, if someone claims to be an aeronautical
> engineer, run, don't walk away from him/her because sooner or later
> they will kill themselves because of their idiotic attitude.

Yes, all AE's are morons - god knows how any airplane ever got
designed. Only through the sarcasm and ignorance of garage mechanics
does advancement in the aeronautical field ever occur.

Feel free to ignore everything I say, Ben - no one's forcing you to
listen. I can back up everything I say with facts, data, theory, and
empirical evidence. Co-workers, some of whose names you might
recognize, agree that bellevilles are a methodology for increasing the
robustness of prop bolt tension retention, and thereby increasing safety.

If you have data to the contrary, please, present it.

Or you can choose to pay no attention - it's a free country. Others
may be interested, however.

> Peace to all... aand mostly to you Marc..

Same.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2007

"stol" > wrote

> After sleeping on this and listening to Jim ,who's comments I have
> read for years and respected I agree I went way too far. It is my Type
> A personality that probably drives me. Also the years of competition
> as a driver has formed my actions of taking no prisoners. On the track
> it's either them or me to the finish line first and I will work to be
> a better human. After all one day I will come face to face to Marc and
> I respect the fact he is a fellow experimantal aircraft builder and
> would like to debate him in a calm way.. As for Spaceship one,,,, my
> take is those guys will make NASA obsolete and stand aviation on its
> ear. You guys rock.....And thanks Jim for pointing out my bad
> attitude...
>
> Peace to all... aand mostly to you Marc..

You are "officially" restored in my book, as a "big man."

It takes a lot of guts to admit to your shortcomings (we all have them, from
time to time) and apologize. Good job.

Maybe someday I can make an auto engine work in an airplane, like you! <g>

> Ps. As for the Steven. P Mc Nicoll thing I will have a harder time
> resolving that issue. <G>

Agreed, 100%, there. I have (in the past)enjoyed hearing the "by the book"
readings of Steven, but he spewed way more than I could swallow, with this
last episode. I know he does not care, but I tossed him in the kill file.

Like everyone, he will get to come out again, some day, and I'll read him
again, and see how it goes. There are only a few people that have a
permanent location in the looney bin! <g>
--
Jim in NC

"Richard Riley" > wrote

>>Ben
>>www.haaspowerair.com
>
> <plonk>

Of course, you can do what you want with your kill file, but Ben might be
worth your second chance. He posted a nice apology, and you probably didn't
see it, because he was already plonked.

Just thought I would let you know.
--
Jim in NC

("Marc J. Zeitlin" wrote)
> The plane is flying well and safely, and I rarely play with myself while
> working on the engine.


"Don't pump it."

"I'm not pumping it!"


Montblack