Real time continuous Prop balancing

[abripl]

This thread is not about how to balance a prop or shop balancing
machines.

Did anyone use BalanceMasters device bolted on their ultralight prop?

These devices apparently balance the prop continuously as you fly.
Similar devices are used on truck wheels - see www.BalanceMasters.com
and www.centramatic.com

[Dan, U.S. Air Force, retired]

abripl wrote:
> This thread is not about how to balance a prop or shop balancing
> machines.
>
> Did anyone use BalanceMasters device bolted on their ultralight prop?
>
> These devices apparently balance the prop continuously as you fly.
> Similar devices are used on truck wheels - see www.BalanceMasters.com
> and www.centramatic.com
>

Which raises the question if the prop is correctly balanced in the first
place why would you need dynamic balancing in an aircraft? It would seem
to me G forces would throw it off anyway.

Dan, U.S. Air Force, retired

[Smitty Two]

In article <Je9xf.78660$sg5.27262@dukeread12>,
"Dan, U.S. Air Force, retired" > wrote:

> abripl wrote:
> > This thread is not about how to balance a prop or shop balancing
> > machines.
> >
> > Did anyone use BalanceMasters device bolted on their ultralight prop?
> >
> > These devices apparently balance the prop continuously as you fly.
> > Similar devices are used on truck wheels - see www.BalanceMasters.com
> > and www.centramatic.com
> >
>
> Which raises the question if the prop is correctly balanced in the first
> place why would you need dynamic balancing in an aircraft? It would seem
> to me G forces would throw it off anyway.
>
> Dan, U.S. Air Force, retired

Maybe because balance changes with prop speed? I don't know anything
about the specific unit in question, but, in theory, an onboard real
time continuous balancer seems useful - at least for the fixed pitch
crowd.

[abripl]

I recently spent $250 for prop balance and it did not work. It was
still about .2 ips out. A factory prop is usually fairly close and all
it needs is a few grams to correct it.
Such a continuous balance device would also take care of imbalance as
the prop gets nicks and scratches. It might even help in flight with
accidental prop damage. These are some of the good reasons...

[ELIPPSE]

There are two things to consider in balancing a prop; mass balance and
aerodynamic balance. You can static balance a prop, but if the mass
distribution is not symmetrical, there will always be a V^2/r
unbalance. If the blades are not symmetrical in chord and pitch at each
station, there will be a force unbalance that will cause a whirl of the
engine on its mounts. This cannot be taken out with mass additions.

[abripl]

You are right about the pitch/cord aerodynamic balance problem. But
such a device would take care of the dynamic balance by far the more
common problem. When you take your prop for balancing to a shop they
only do the dynamic balance. You would have to return the prop to the
manufacturer for pitch/cord problems. But usually pitch/cord problems
are rare - its like having a bent wheel on a car, where most problems
are with dynamic balance.

[Capt. Geoffrey Thorpe]

"abripl" > wrote in message
ups.com...
....
> Did anyone use BalanceMasters device bolted on their ultralight prop?
>
> These devices apparently balance the prop continuously as you fly.
> Similar devices are used on truck wheels - see www.BalanceMasters.com
> and www.centramatic.com

I'll give them an 8.5 on the bull**** scale.

I can rub your prop with a chicken bone to improve the strength for a lot
less money.

--
Geoff
the sea hawk at wow way d0t com
remove spaces and make the obvious substitutions to reply by mail
Spell checking is left as an excercise for the reader.

[ELIPPSE]

Actually, the pitch thingie is not all that uncommon. Consider: if your
prop has a 6" diameter hub, and the prop is mounted such that there is
a tilt across the long axis where one side is .01" off relative to the
other, one blade will be at 0.1 degree more pitch, and the other will
be at 0.1 degree less pitch. With CL slope being 0.1/deg, if the prop
blades are designed for a CL of 0.35, one blade will be at a CL of
0.34, and the other will be at a CL of 0.36. That's a 5.9% difference
in thrust between the two blades. You won't see this with tracking.
Let's say you have an airplane with an O-320 and are operating at 75%
power with a prop efficiency of 80% at 200 mph. Your prop is developing
180 lb thrust total; one blade is developing 87.4 lb thrust, the other
is developing 92.6 lb thrust. There is a 5.1lb differential between the
two blades, which tries to whirl the motor on its mounts. You will
never get the prop balanced, and the more thrust you develope, the more
shake you get. Been there, done that!

[abripl]

El.,

You are still talking about a manufacturing control problem or perhaps
worn CS gear problem. Both are solved by either returning the prop back
or replacing parts. I had similar issue with my IVO magnum prop (200hp
franklin) in which case an exchange of blades improved the situation.
Generally once you take care of that problem it does not return. But
dynamic imbalance can be a recuring problem - simple nicks or blade
wear will do it.

[abripl]

> I'll give them an 8.5 on the bull**** scale...

Thank you for your technical help. I assume you have tried them
yourself and are giving an objective observation.

[Capt. Geoffrey Thorpe]

"abripl" > wrote in message
oups.com...
>> I'll give them an 8.5 on the bull**** scale...
>
> Thank you for your technical help. I assume you have tried them
> yourself and are giving an objective observation.
>

Try them? You've got to be kidding.

To quote the web pages:

"However, when sudden braking or slowing occurs, the fluids continue to spin
for several revolutions until they slow down to the wheel speed. Therefore,
the fluid moving at high speed and weighing nearly 28 ounces per wheel whip
around the ring at ten to fifteen revolutions per second. This weight, when
pulled by gravity over the top of the wheel, "falls" over the front side of
the wheel where the force is created which "pulls" the wheel down onto the
pavement-JUST WHEN YOU NEED IT TO-on sudden braking over hard bumps or
across sheets of water to create a road-hugging controlability and
anti-sway, anti-drift and anti-trailer hop and bounce effect"

RiiiiIIIiiight.

Or, from the other web page:

"The Company claims the dissimilar metallic composition of the balancer,
i.e. steel mounting plate and aluminum balancing ring, dissipates wheel/tire
heating while in operation. This feature is called "ThermoFlow" by the
Company. Basic rules of thermal physics apply as different metals have
different coefficients of contraction/expansion with convection heat
transfer migrating to the metallic content with the highest coefficient of
expansion/contraction, i.e. rapid transfer from the wheel/hub/tire assembly
to the steel mounting plate to the aluminum tube."

You don't have to pay for bull**** to smell bull****.

8.5 - you can't get a 10.0 without invoking space aliens AND anti-gravity.

--
Geoff
the sea hawk at wow way d0t com
remove spaces and make the obvious substitutions to reply by mail
Spell checking is left as an excercise for the reader.

[Cy Galley]

I think the down force is the result of gyroscopic precession which is 90 °
for the applied force. Balance rings are not new. Mark Landrol sells one
for RVs with wooden prop that many are happy about.




"Capt. Geoffrey Thorpe" <The Sea Hawk at wow way d0t com> wrote in message
...
> "abripl" > wrote in message
> oups.com...
>>> I'll give them an 8.5 on the bull**** scale...
>>
>> Thank you for your technical help. I assume you have tried them
>> yourself and are giving an objective observation.
>>
>
> Try them? You've got to be kidding.
>
> To quote the web pages:
>
> "However, when sudden braking or slowing occurs, the fluids continue to
> spin for several revolutions until they slow down to the wheel speed.
> Therefore, the fluid moving at high speed and weighing nearly 28 ounces
> per wheel whip around the ring at ten to fifteen revolutions per second.
> This weight, when pulled by gravity over the top of the wheel, "falls"
> over the front side of the wheel where the force is created which "pulls"
> the wheel down onto the pavement-JUST WHEN YOU NEED IT TO-on sudden
> braking over hard bumps or across sheets of water to create a road-hugging
> controlability and anti-sway, anti-drift and anti-trailer hop and bounce
> effect"
>
> RiiiiIIIiiight.
>
> Or, from the other web page:
>
> "The Company claims the dissimilar metallic composition of the balancer,
> i.e. steel mounting plate and aluminum balancing ring, dissipates
> wheel/tire heating while in operation. This feature is called "ThermoFlow"
> by the Company. Basic rules of thermal physics apply as different metals
> have different coefficients of contraction/expansion with convection heat
> transfer migrating to the metallic content with the highest coefficient of
> expansion/contraction, i.e. rapid transfer from the wheel/hub/tire
> assembly to the steel mounting plate to the aluminum tube."
>
> You don't have to pay for bull**** to smell bull****.
>
> 8.5 - you can't get a 10.0 without invoking space aliens AND anti-gravity.
>
> --
> Geoff
> the sea hawk at wow way d0t com
> remove spaces and make the obvious substitutions to reply by mail
> Spell checking is left as an excercise for the reader.
>

[abripl]

> RiiiiIIIiiight.
> You don't have to pay for bull**** to smell bull****.
> 8.5 - you can't get a 10.0 without invoking space aliens AND anti-gravity.

I just love all your scientific savy.

[Fly]

I've wondered about these. By both brands, there is a mass of weights and
fluids that counteract the shake of imbalance.


I never made it past Phy101 but how I see the problem is that a heavy spot
of imbalance provokes a rotating object to a larger orbit. The instance
of a car tire bouncing I have witnessed myself, but the low side was always
constrained by the pavement.
So, what causes the correction mass to seek the lighter low side?

And what happens under the influence of an engines torsion vibration? The
quick back & forth of the crank's twist, the wind and unwinding,
Is the mass be heavy enough to lag behind the twist of how many.... 8 or 12
twists per revolution??

My guess about the rings on Rv's with the wooden props is its simply a
matter having enough mass on the crank to absorb the torsion of the engine.
Somethig heavy enough to steady down the running of the engine...Somewhat
similar to running a chevy small block minus a flywheel, on the shop floor!.

And a big question of all... why don't we commonly see more of these
mechanisms on vehicles?

Kent Felkins
Tulsa











"Cy Galley" > wrote in message
news:7Jjxf.698432$_o.515003@attbi_s71...
> I think the down force is the result of gyroscopic precession which is 90
°
> for the applied force. Balance rings are not new. Mark Landrol sells one
> for RVs with wooden prop that many are happy about.
>
>
>
>
> "Capt. Geoffrey Thorpe" <The Sea Hawk at wow way d0t com> wrote in message
> ...
> > "abripl" > wrote in message
> > oups.com...
> >>> I'll give them an 8.5 on the bull**** scale...
> >>
> >> Thank you for your technical help. I assume you have tried them
> >> yourself and are giving an objective observation.
> >>
> >
> > Try them? You've got to be kidding.
> >
> > To quote the web pages:
> >
> > "However, when sudden braking or slowing occurs, the fluids continue to
> > spin for several revolutions until they slow down to the wheel speed.
> > Therefore, the fluid moving at high speed and weighing nearly 28 ounces
> > per wheel whip around the ring at ten to fifteen revolutions per second.
> > This weight, when pulled by gravity over the top of the wheel, "falls"
> > over the front side of the wheel where the force is created which
"pulls"
> > the wheel down onto the pavement-JUST WHEN YOU NEED IT TO-on sudden
> > braking over hard bumps or across sheets of water to create a
road-hugging
> > controlability and anti-sway, anti-drift and anti-trailer hop and bounce
> > effect"
> >
> > RiiiiIIIiiight.
> >
> > Or, from the other web page:
> >
> > "The Company claims the dissimilar metallic composition of the balancer,
> > i.e. steel mounting plate and aluminum balancing ring, dissipates
> > wheel/tire heating while in operation. This feature is called
"ThermoFlow"
> > by the Company. Basic rules of thermal physics apply as different metals
> > have different coefficients of contraction/expansion with convection
heat
> > transfer migrating to the metallic content with the highest coefficient
of
> > expansion/contraction, i.e. rapid transfer from the wheel/hub/tire
> > assembly to the steel mounting plate to the aluminum tube."
> >
> > You don't have to pay for bull**** to smell bull****.
> >
> > 8.5 - you can't get a 10.0 without invoking space aliens AND
anti-gravity.
> >
> > --
> > Geoff
> > the sea hawk at wow way d0t com
> > remove spaces and make the obvious substitutions to reply by mail
> > Spell checking is left as an excercise for the reader.
> >
>
>

[abripl]

Fly,

There are more than just those two companies making them - like
www.taabs-int.com, www.imiproducts.com and some reference to
http://www.tirelife.com/
An article that discusses that is at
http://www.landlinemag.com/Archives/2003/Jun03/equipment/tires_life.htm

There are several independent reviews of the devices and all indicate
they work. There is an interesting demo machine that Centramatic.com
distributies to ilustrate the balancing effect on a demo wheel. A demo
video is available at http://www.centramatic.com/Demo/video2.mpg

As far as I see it does not violate conservation of angular momentum.
A free body in space will always be in angular balance about its CM
whereas that is not the same case for rigid bodies rotating about a
fixed axis - maybe that is the key: there extra bodies free to move.

As to why they are not used more... probably the extra cost is
prohibitive, to say an automobile where a $20 tire balance will do. But
for big trucks it can pay off.

I am not promoting the devices, but just have an open mind. Its so easy
to put down others and not be creative oneself.

[Andy Asberry]

On 11 Jan 2006 18:22:58 -0800, "abripl" >
wrote:

>> I'll give them an 8.5 on the bull**** scale...
>
>Thank you for your technical help. I assume you have tried them
>yourself and are giving an objective observation.

I can't say I've tried them all but I have tried a bunch of them. I've
been in the tire business for over 40 years. After radial tires became
popular but before computer balancers were available we tried
everything to give customers a smooth ride.

Several of the oil/ball bearing rings, sand, plastic beads, windshield
washer fluid. Some truckers even put 3 golf balls in their tires. The
thing with all these ring type "balancers" is they are on a single
plane. They do nothing for side to side imbalance.

We tried them with on-the-car strobe and computer balancers. The only
thing that was constant was that the imbalance would move every time
you stopped the tire.

Spend your money how you please but I won't use them if they are free.

[abripl]

> The thing with all these ring type "balancers" is they are on a single
> plane. They do nothing for side to side imbalance. ...

That is all that is done for props. When you take your prop in for
dynamic balance all they do is add weights to the spinner ring -
"single plane balancing".

[Barnyard BOb -]

"abripl" > wrote:

>Such a continuous balance device would also take care of imbalance as
>the prop gets nicks and scratches. It might even help in flight with
>accidental prop damage. These are some of the good reasons...
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Not to mention this could well be a solution in search of a problem.

When it comes to RELIABLE flying...

- KISS -

K eep
I t
S imple
S toopid.


- Barnyard BOb - more than a half century of flight

[[email protected]]

Hi,

I believe that such balancers are possible. I have seen
such a system on a washing machine probably
made in the 1960s. Huge initial shake, big clunks,
perfect balance.

http://www.monografias.com/trabajos17/automatic-compensating/automatic-compensating.shtml
Very mathemetical paper but may be a start for a search.

A while back I did a bit of googling on such balancers but
I forget the results now but seem to recall an application
in some reasonably high volume device. Chain saw?

[Richard Lamb]

abripl wrote:
> This thread is not about how to balance a prop or shop balancing
> machines.
>
> Did anyone use BalanceMasters device bolted on their ultralight prop?
>
> These devices apparently balance the prop continuously as you fly.
> Similar devices are used on truck wheels - see www.BalanceMasters.com
> and www.centramatic.com
>

ya know, if we consider this to be a wood UL prop (US style),
it doesn't weigh more than about 5 ot 6 pounds.

If the prop static balances ok, but still vibrates badly enough to
cause concern, I think I'd just replace it because it obviously has
a problem.

A couple of hundred bucks for a new Tennessee Props propeller isn't
that bad - specially when the alternative is throwing a prop blade
in flight.

Just a thought...


Richard

[abripl]

Richard,

5 or 6 pounds??? you are talking about an ultralight. I am interested
in 200hp engine props. It is recommended to dynamic balance a prop
after you get it. A dynamic balance costs about $200+. After a few
years of nicks you might want to finish it and balance it again. One of
these devices is about $100 when made in quantities and usable for
several props.


Richard Lamb wrote:
> ya know, if we consider this to be a wood UL prop (US style),
> it doesn't weigh more than about 5 ot 6 pounds.
>
> If the prop static balances ok, but still vibrates badly enough to
> cause concern, I think I'd just replace it because it obviously has
> a problem.
>
> A couple of hundred bucks for a new Tennessee Props propeller isn't
> that bad - specially when the alternative is throwing a prop blade
> in flight.
>
> Just a thought...
>
>
> Richard