Dynamic Prop Balancer

[Robert Scott]

Can anyone tell me how a dynamic prop balancer works? I have heard that it
involves an accelerometer to detect vibration, but it what do they use to detect
the prop position to correlate with that accelerometer? Could it be an optical
pickup from a mark placed on the prop? Or perhaps a pickup from the magneto?
Although a mag pickup would be ambiguous by 180 degrees, I think. I was just
brainstorming on how I might design one from scratch.

Robert Scott
Ypsilanti, Michigan

[[email protected]]

On Mar 4, 7:28 am, ---@--- (Robert Scott) wrote:
> Can anyone tell me how a dynamic prop balancer works? I have heard that it
> involves an accelerometer to detect vibration, but it what do they use to detect
> the prop position to correlate with that accelerometer? Could it be an optical
> pickup from a mark placed on the prop? Or perhaps a pickup from the magneto?
> Although a mag pickup would be ambiguous by 180 degrees, I think. I was just
> brainstorming on how I might design one from scratch.
>
> Robert Scott
> Ypsilanti, Michigan

I believe an optical pickup is placed on the cowl with a reflector on
one of the prop blades.

[[email protected]]

On Mar 4, 5:28 am, ---@--- (Robert Scott) wrote:
> Can anyone tell me how a dynamic prop balancer works? I have heard that it
> involves an accelerometer to detect vibration, but it what do they use to detect
> the prop position to correlate with that accelerometer? Could it be an optical
> pickup from a mark placed on the prop? Or perhaps a pickup from the magneto?
> Although a mag pickup would be ambiguous by 180 degrees, I think. I was just
> brainstorming on how I might design one from scratch.
>
> Robert Scott
> Ypsilanti, Michigan

On the Acers unit I use to balance my prop the accelerometer is bolted
to the centerline of the engine in the proper direction. That sensor
is position sensitive. The light sender is taped on the top of the
cowling facing forward shining on the prop. it is about 13" away from
the reflective tape thats applied to the prop. The handheld unit is
routed into the cockpit using long cables from both sensors. The thing
works amazingly good. My last balance procedure got the prop/ spinner
to within .001 IPS. The smoothness is well worth the hour or so of
setup and running...

Ben
www.haaspowerair.com

[RST Engineering]

I've got one in the back of my head that I want to use for a future
Kitplanes article. I'm going to use an old phonograph cartridge with a
short "ball on the end of a needle" as my accelerometer and I was seriously
thinking of an inductive pickup on the #1 plug wire. The optical gig was
also a consideration, but I got to thinking how that would work out in the
sunlight.

Jim


"Robert Scott" <---@---> wrote in message
...
> Can anyone tell me how a dynamic prop balancer works? I have heard that
> it
> involves an accelerometer to detect vibration, but it what do they use to
> detect
> the prop position to correlate with that accelerometer? Could it be an
> optical
> pickup from a mark placed on the prop? Or perhaps a pickup from the
> magneto?
> Although a mag pickup would be ambiguous by 180 degrees, I think. I was
> just
> brainstorming on how I might design one from scratch.
>
> Robert Scott
> Ypsilanti, Michigan

[Tim]

Robert Scott wrote:
> Can anyone tell me how a dynamic prop balancer works? I have heard that it
> involves an accelerometer to detect vibration, but it what do they use to detect
> the prop position to correlate with that accelerometer? Could it be an optical
> pickup from a mark placed on the prop? Or perhaps a pickup from the magneto?
> Although a mag pickup would be ambiguous by 180 degrees, I think. I was just
> brainstorming on how I might design one from scratch.
>
> Robert Scott
> Ypsilanti, Michigan


No idea, but can anyone recommend a shop that will balance my single
engine grumman - one close to KISP - Long Island NY? I have no problems
travelling to CT or RI or MA or VT for this - might make a day trip out
of it.

thanks

[Peter Clark]

On Sun, 04 Mar 2007 13:55:54 -0500, Tim >
wrote:

>No idea, but can anyone recommend a shop that will balance my single
>engine grumman - one close to KISP - Long Island NY? I have no problems
>travelling to CT or RI or MA or VT for this - might make a day trip out
>of it.

Keyson at Nashua, NH.

[Tim]

Peter Clark wrote:
> On Sun, 04 Mar 2007 13:55:54 -0500, Tim >
> wrote:
>
>
>>No idea, but can anyone recommend a shop that will balance my single
>>engine grumman - one close to KISP - Long Island NY? I have no problems
>>travelling to CT or RI or MA or VT for this - might make a day trip out
>>of it.
>
>
> Keyson at Nashua, NH.

ok, thanks. that's a hike, but it would be a fun trip. I might wait
until it warms up a bit.

[Peter Clark]

On Sun, 04 Mar 2007 19:38:28 -0500, Tim >
wrote:

>Peter Clark wrote:
>> On Sun, 04 Mar 2007 13:55:54 -0500, Tim >
>> wrote:
>>
>>
>>>No idea, but can anyone recommend a shop that will balance my single
>>>engine grumman - one close to KISP - Long Island NY? I have no problems
>>>travelling to CT or RI or MA or VT for this - might make a day trip out
>>>of it.
>>
>>
>> Keyson at Nashua, NH.
>
>ok, thanks. that's a hike, but it would be a fun trip. I might wait
>until it warms up a bit.

Yea, and they like to see winds of ~10 or less for best results. The
restaurant is closed on (Wednesday?). Call ahead and ask for Byron to
confirm they'll do the model (I doubt you'll have a problem with
practically any single/multi engine piston though). I've done the
stay-and-wait thing, it generally runs them around +- 3 hours from
sign in to release.

[[email protected]]

On Mar 4, 6:06 pm, Peter Clark
> wrote:
> On Sun, 04 Mar 2007 19:38:28 -0500, Tim >
> wrote:
>
> >Peter Clark wrote:
> >> On Sun, 04 Mar 2007 13:55:54 -0500, Tim >
> >> wrote:
>
> >>>No idea, but can anyone recommend a shop that will balance my single
> >>>engine grumman - one close to KISP - Long Island NY? I have no problems
> >>>travelling to CT or RI or MA or VT for this - might make a day trip out
> >>>of it.
>
> >> Keyson at Nashua, NH.
>
> >ok, thanks. that's a hike, but it would be a fun trip. I might wait
> >until it warms up a bit.
>
> Yea, and they like to see winds of ~10 or less for best results. The
> restaurant is closed on (Wednesday?). Call ahead and ask for Byron to
> confirm they'll do the model (I doubt you'll have a problem with
> practically any single/multi engine piston though). I've done the
> stay-and-wait thing, it generally runs them around +- 3 hours from
> sign in to release.

The only way to get perfect results is for the wind to be calm. A 10
MPH breeze give you false readings, At least it does on the Acers
unit.. YMMV...

Ben
www.haaspowerair.com

[Robert Scott]

On 5 Mar 2007 06:41:42 -0800, " > wrote:
>The only way to get perfect results is for the wind to be calm. A 10
>MPH breeze give you false readings, At least it does on the Acers
>unit.. YMMV...

Are you saying that a 10 MPH breeze causes a perfectly balanced prop to vibrate
noticeably?


Robert Scott
Ypsilanti, Michigan

[[email protected]]

On Mar 6, 6:16 am, ---@--- (Robert Scott) wrote:
> On 5 Mar 2007 06:41:42 -0800, " > wrote:
>
> >The only way to get perfect results is for the wind to be calm. A 10
> >MPH breeze give you false readings, At least it does on the Acers
> >unit.. YMMV...
>
> Are you saying that a 10 MPH breeze causes a perfectly balanced prop to vibrate
> noticeably?
>
> Robert Scott
> Ypsilanti, Michigan

Nope... What happens is the wind gusts during the actual balancing
operation will affect the unit from stabilizing and giving you a good
location and amount of weight to add. You can balance in the wind and
get close but why not get it perfect. If there is a row of T hangars
or something to block the wind just get behind them. No reason to not
use a wind break,.. YMMV

[Robert Scott]

On 6 Mar 2007 06:23:10 -0800, " > wrote:

>On Mar 6, 6:16 am, ---@--- (Robert Scott) wrote:
>> On 5 Mar 2007 06:41:42 -0800, " > wrote:
>>
>> >The only way to get perfect results is for the wind to be calm. A 10
>> >MPH breeze give you false readings, At least it does on the Acers
>> >unit.. YMMV...
>>
>> Are you saying that a 10 MPH breeze causes a perfectly balanced prop to vibrate
>> noticeably?
>>
>> Robert Scott
>> Ypsilanti, Michigan
>
>Nope... What happens is the wind gusts during the actual balancing
>operation will affect the unit from stabilizing and giving you a good
>location and amount of weight to add...

How long does it normally take, running at full RPM, to get a stable reading on
one of these balancer systems?


Robert Scott
Ypsilanti, Michigan

[Allen[_1_]]

"Robert Scott" <---@---> wrote in message
...
> On 6 Mar 2007 06:23:10 -0800, " > wrote:
>
> >On Mar 6, 6:16 am, ---@--- (Robert Scott) wrote:
> >> On 5 Mar 2007 06:41:42 -0800, " >
wrote:
> >>
> >> >The only way to get perfect results is for the wind to be calm. A 10
> >> >MPH breeze give you false readings, At least it does on the Acers
> >> >unit.. YMMV...
> >>
> >> Are you saying that a 10 MPH breeze causes a perfectly balanced prop to
vibrate
> >> noticeably?
> >>
> >> Robert Scott
> >> Ypsilanti, Michigan
> >
> >Nope... What happens is the wind gusts during the actual balancing
> >operation will affect the unit from stabilizing and giving you a good
> >location and amount of weight to add...
>
> How long does it normally take, running at full RPM, to get a stable
reading on
> one of these balancer systems?
>
>
> Robert Scott
> Ypsilanti, Michigan

The machine tells you when it is getting a good reading (usually after about
30 seconds or so at power depending on conditions) then you hit the record
button and and 3-4 seconds later you have your reading. I am not sure if we
are talking about the same machine, ours is an Aces.

Allen

[[email protected]]

On Mar 7, 5:54 am, "Allen" > wrote:
> "Robert Scott" <---@---> wrote in message
>
> ...
>
>
>
>
>
> > On 6 Mar 2007 06:23:10 -0800, " > wrote:
>
> > >On Mar 6, 6:16 am, ---@--- (Robert Scott) wrote:
> > >> On 5 Mar 2007 06:41:42 -0800, " >
> wrote:
>
> > >> >The only way to get perfect results is for the wind to be calm. A 10
> > >> >MPH breeze give you false readings, At least it does on the Acers
> > >> >unit.. YMMV...
>
> > >> Are you saying that a 10 MPH breeze causes a perfectly balanced prop to
> vibrate
> > >> noticeably?
>
> > >> Robert Scott
> > >> Ypsilanti, Michigan
>
> > >Nope... What happens is the wind gusts during the actual balancing
> > >operation will affect the unit from stabilizing and giving you a good
> > >location and amount of weight to add...
>
> > How long does it normally take, running at full RPM, to get a stable
> reading on
> > one of these balancer systems?
>
> > Robert Scott
> > Ypsilanti, Michigan
>
> The machine tells you when it is getting a good reading (usually after about
> 30 seconds or so at power depending on conditions) then you hit the record
> button and and 3-4 seconds later you have your reading. I am not sure if we
> are talking about the same machine, ours is an Aces.
>
> Allen- Hide quoted text -
>
> - Show quoted text -

It's the same machine and the same time to aquire the info...