Today's Message Index:
----------------------
1. 04:48 AM - Re: Dyna Vibe Prop Dynamic Balancer Question (Roger Lee)
2. 05:22 AM - Re: Re: Dyna Vibe Prop Dynamic Balancer Question (FLYaDIVE)
3. 05:42 AM - Re: Dyna Vibe Prop Dynamic Balancer Question (FLYaDIVE)
4. 07:30 AM - Re: Dyna Vibe Prop Dynamic Balancer Question (JohnF)
5. 09:08 AM - Re: Dyna Vibe Prop Dynamic Balancer Question (FLYaDIVE)
6. 10:11 AM - Re: Dyna Vibe Prop Dynamic Balancer Question (FLYaDIVE)
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| Subject: | Re: Dyna Vibe Prop Dynamic Balancer Question |
Hi John,
Sorry I'm out of the info loop on this one. I don't have a clue.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Repair Center - Heavy Maint. Rated
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=417561#417561
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| Subject: | Re: Dyna Vibe Prop Dynamic Balancer Question |
John:
I missed the question... I have a Dyna Vibe, how can I help?
Barry
On Sat, Jan 25, 2014 at 7:47 AM, Roger Lee <ssadiver1@yahoo.com> wrote:
>
> Hi John,
>
> Sorry I'm out of the info loop on this one. I don't have a clue.
>
> --------
> Roger Lee
> Tucson, Az.
> Light Sport Repairman - Maintenance Rated
> Rotax Repair Center - Heavy Maint. Rated
> Home 520-574-1080 TRY HOME FIRST
> Cell 520-349-7056
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=417561#417561
>
>
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| Subject: | Re: Dyna Vibe Prop Dynamic Balancer Question |
Hi John:
I just read the original post.
The answer is: It Can't!
It has to be a misprint.
I'm thinking it is easier to describe the accelerometer by identifying the
cable as apposed to the mounting threads. Which will be hidden when mounted.
Can you tell me what page that statement is on? And also what revision of
the manual you are reading?
If you really wanted to attempt something crazy, YES, you could make a
mount that points the accelerometer way from the HUB (Center of the shaft).
And that would give you the Lite Point, but, you would probably be adding
all sorts of erroneous vibrations due to the extended size of the bracket.
I do not understand why Dyna Vibe did not simply have the feature of
REVERSING the math or the output of the accelerometer. Or why they
used such a large housing for the accelerometer; phones and iPads have
surface mount accelerometers that are only 0.100" high and 0.250" square.
Take that and pot it and you are done. Oh, well! It works.
Barry
On Fri, Jan 24, 2014 at 11:49 PM, JohnF <n29cx@ridgeviewtel.us> wrote:
>
> Maybe Roger Lee can answer this one:
>
> I purchased a Dyna Vibe dynamic prop balancer and the instructions seem
> clear except for this statement:
>
> "If the accelerometer cable is pointing away from the center of the bub,
> then the angle reported by the Dyna Vibe is the HEAVY spot (where to remove
> weight, or 180 degrees from where to add weight.) If you flip it so the
> accelerometer cable is pointing toward the hub, then the reading will
> indicate the light spot (where to ADD weight.)"
>
> Question: How can be orientation of the cable (not the accelerometer)
> change what the reading angle means? (ie, heavy or light)
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=417551#417551
>
>
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| Subject: | Re: Dyna Vibe Prop Dynamic Balancer Question |
Barry, thank you for the response. The statement is on page 33 of the
manual, second paragraph from the bottom. I have version 1-07. I am
repeating below the answer I got from Dyna Vibe which I will have to
read and re-read several times to try to understand it..
One other question I have is just exactly what is the 'axis of the
accelerometer' - is the vertical orientation of the unit, or some
rotational position? I don't have a clue.
Anyway, here is the answer from RPX...maybe you can help me clarify what
they are telliing me.
Fun question.
It has to do with the timing of the signals and what the accelerometer
"feels" vs when it feels it with respect to the optical tach signal. If
the accelerometer is rotated 180 degrees then the signals are backwards.
That's why the solution flips (heavy vs light). If you are 90 degrees,
then you will sense engine rotation in addition to vibration but the
vibration will be rotated 90 degrees and mixed with rotational
vibration. So that's not really useful. If you are at 45 degrees, then
you will sense rotation and vibration, but at a complex angle. So the
math would be quite convolved. You would have to separate rotation, x
vibration, and y vibration, which can't be done without more sensors to
see what is going on.
But I don't think you are looking for the literal answer to your
question. So the actual answer is that you want the axis of the
accelerometer pointing toward the center of rotation. If it isn't, then
you start sensing rotational vibration which isn't what you are looking
for. And if the sensor is backwards, then the math in the meter will be
backwards. Which explains the heavy vs light statement
Thanks again for your ehlp.
John
----- Original Message -----
From: FLYaDIVE
To: rotaxengines-list@matronics.com
Sent: Saturday, January 25, 2014 6:42 AM
Subject: Re: RotaxEngines-List: Dyna Vibe Prop Dynamic Balancer
Question
Hi John:
I just read the original post.
The answer is: It Can't!
It has to be a misprint.
I'm thinking it is easier to describe the accelerometer by identifying
the cable as apposed to the mounting threads. Which will be hidden when
mounted.
Can you tell me what page that statement is on? And also what
revision of the manual you are reading?
If you really wanted to attempt something crazy, YES, you could make a
mount that points the accelerometer way from the HUB (Center of the
shaft). And that would give you the Lite Point, but, you would probably
be adding all sorts of erroneous vibrations due to the extended size of
the bracket. I do not understand why Dyna Vibe did not simply have the
feature of REVERSING the math or the output of the accelerometer. Or
why they used such a large housing for the accelerometer; phones and
iPads have surface mount accelerometers that are only 0.100" high and
0.250" square. Take that and pot it and you are done. Oh, well! It
works.
Barry
On Fri, Jan 24, 2014 at 11:49 PM, JohnF <n29cx@ridgeviewtel.us> wrote:
<n29cx@ridgeviewtel.us>
Maybe Roger Lee can answer this one:
I purchased a Dyna Vibe dynamic prop balancer and the instructions
seem clear except for this statement:
"If the accelerometer cable is pointing away from the center of the
bub, then the angle reported by the Dyna Vibe is the HEAVY spot (where
to remove weight, or 180 degrees from where to add weight.) If you flip
it so the accelerometer cable is pointing toward the hub, then the
reading will indicate the light spot (where to ADD weight.)"
Question: How can be orientation of the cable (not the
accelerometer) change what the reading angle means? (ie, heavy or light)
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=417551#417551
==========
-List"
target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List
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le, List Admin.
="_blank">http://www.matronics.com/contribution
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Message 5
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| Subject: | Re: Dyna Vibe Prop Dynamic Balancer Question |
John:
The answer can be quite confusing. Why? Because I'm an engineer and there
are no simple answers ;-)
Ok, the short version:
There are Three (3) primary axis's: X - Y - Z
X - is the Horizontal axis from Left to Right.
Y - Is the Vertical axis and is perpendicular to the X axis consider the
letter L
Z - is ... Harder to explain, take the letter L and draw a line from the
point where the Vertical and Horizontal come together BUT - Draw it
straight out towards you.
Now, 'axis of the accelerometer'. That is the way it is mounted... It
should be Vertical - Straight Up and Down. AND mounted ON TOP of the engine
- - - What Dyna Vibe is also explaining is the relationship between the
Accelerometer and the Photo Eye for obtaining the RPM. ALL your reading
will be in reference to the photo eye and what you deem the #1 blade of the
prop. The degree position of rotation is in relationship to the photo eye.
SO... If the Accelerometer is mounted on the Center-Line (C/L) of the
engine and the photo eye is off to one side (as in the pictures in the
manual) the degree indication of the Heavy point will NOT align with the
Accelerometer. AND THIS will drive you crazy when you try to put the
balance weights on. Example: The Dyna Vibe will say the heavy point is 090
Deg... You add 180 Deg and get 270 Deg... BUT! The photo eye is OFF C/L
to the right (facing) by say 1"... That will ADD about 15 Deg to the 270
reading and give you 285 Deg for the lite point. If you do
not consider this little fact you will chasing your tail trying to find the
prop balance point.
How do you correct this error? Make a bracket that puts the Accelerometer
and Photo Eye on the same Vertical Y axis.
I should sell these brackets but the price would be too high...
I read the response from Dyna Vibe... Yea, I understand it but it is
not very clear. They could have done a better job. Go with my
above explanation and things will work out correctly.
Now, my question: What plane and engine are you trying to balance?
I want to balance a friends Rotax Pusher but there is NO ring
gear/flywheel, where can I put the weights? It is also a three (3) blade
prop. <-- That makes no difference - Can do!
Barry
On Sat, Jan 25, 2014 at 10:30 AM, JohnF <n29cx@ridgeviewtel.us> wrote:
> Barry, thank you for the response. The statement is on page 33 of the
> manual, second paragraph from the bottom. I have version 1-07. I am
> repeating below the answer I got from Dyna Vibe which I will have to read
> and re-read several times to try to understand it..
>
> One other question I have is just exactly what is the 'axis of the
> accelerometer' - is the vertical orientation of the unit, or some
> rotational position? I don't have a clue.
>
> Anyway, here is the answer from RPX...maybe you can help me clarify what
> they are telliing me.
>
>
> Fun question.
>
> It has to do with the timing of the signals and what the accelerometer
> =93feels=94 vs when it feels it with respect to the optical tach signal.
If the
> accelerometer is rotated 180 degrees then the signals are backwards. That
=92s
> why the solution flips (heavy vs light). If you are 90 degrees, then you
> will sense engine rotation in addition to vibration but the vibration wil
l
> be rotated 90 degrees and mixed with rotational vibration. So that=92s no
t
> really useful. If you are at 45 degrees, then you will sense rotation and
> vibration, but at a complex angle. So the math would be quite convolved.
> You would have to separate rotation, x vibration, and y vibration, which
> can=92t be done without more sensors to see what is going on.
>
> But I don=92t think you are looking for the literal answer to your
> question. So the actual answer is that you want the axis of the
> accelerometer pointing toward the center of rotation. If it isn=92t, then
you
> start sensing rotational vibration which isn=92t what you are looking for
.
> And if the sensor is backwards, then the math in the meter will be
> backwards. Which explains the heavy vs light statement
> Thanks again for your ehlp.
>
> John
>
>
> ----- Original Message -----
> *From:* FLYaDIVE <flyadive@gmail.com>
> *To:* rotaxengines-list@matronics.com
> *Sent:* Saturday, January 25, 2014 6:42 AM
> *Subject:* Re: RotaxEngines-List: Dyna Vibe Prop Dynamic Balancer Questio
n
>
> Hi John:
>
> I just read the original post.
> The answer is: It Can't!
> It has to be a misprint.
> I'm thinking it is easier to describe the accelerometer by identifying th
e
> cable as apposed to the mounting threads. Which will be hidden when mount
ed.
> Can you tell me what page that statement is on? And also what revision o
f
> the manual you are reading?
>
> If you really wanted to attempt something crazy, YES, you could make a
> mount that points the accelerometer way from the HUB (Center of the
> shaft). And that would give you the Lite Point, but, you would probably
be
> adding all sorts of erroneous vibrations due to the extended size of the
> bracket. I do not understand why Dyna Vibe did not simply have the featu
re
> of REVERSING the math or the output of the accelerometer. Or why they
> used such a large housing for the accelerometer; phones and iPads have
> surface mount accelerometers that are only 0.100" high and 0.250" square.
> Take that and pot it and you are done. Oh, well! It works.
>
> Barry
>
>
> On Fri, Jan 24, 2014 at 11:49 PM, JohnF <n29cx@ridgeviewtel.us> wrote:
>
>>
>> Maybe Roger Lee can answer this one:
>>
>> I purchased a Dyna Vibe dynamic prop balancer and the instructions seem
>> clear except for this statement:
>>
>> "If the accelerometer cable is pointing away from the center of the bub,
>> then the angle reported by the Dyna Vibe is the HEAVY spot (where to rem
ove
>> weight, or 180 degrees from where to add weight.) If you flip it so the
>> accelerometer cable is pointing toward the hub, then the reading will
>> indicate the light spot (where to ADD weight.)"
>>
>> Question: How can be orientation of the cable (not the accelerometer)
>> change what the reading angle means? (ie, heavy or light)
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=417551#417551
>>
>>
>>
>>
>>
>>
>>
>> ==========
>> -List" target="_blank">
>> http://www.matronics.com/Navigator?RotaxEngines-List
>> ==========
>> http://forums.matronics.com
>> ==========
>> le, List Admin.
>> ="_blank">http://www.matronics.com/contribution
>> ==========
>>
>>
>>
>>
> *
>
> href="http://www.matronics.com/Navigator?RotaxEngines-List <http://www.
matronics.com/Navigator?RotaxEngines-List>">http://www.matronics.com/Naviga
tor?RotaxEngines-List <http://www.matronics.com/Navigator?RotaxEngines-List
>
> href="http://forums.matronics.com <http://forums.matronics.com>">http:/
/forums.matronics.com <http://forums.matronics.com>
> href="http://www.matronics.com/contribution <http://www.matronics.com/c
ontribution>">http://www.matronics.com/c <http://www.matronics.com/c>
> *
>
> *
>
===========
www.matronics.com/Navigator?RotaxEngines-List>
===========
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===========
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>
>
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| Subject: | Re: Dyna Vibe Prop Dynamic Balancer Question |
Right you are John!
"I agree that RXP could improve their manual.....its hard to write clearly
when you have total knowledge of the subject and are writing to someone
else that isn't on board yet. You can easily forget to be detailed enough
to satisfy the uninformed mind.
Cheers
John"
John:
I wrote many a procedure and manual and you have to write as if the person
reading is not in the room with you and had no knowledge of the subject. I
use to say many a tech writer cannot see the forest, for the trees. Just
look at Micro Soft... The information they supplied was totally accurate,
but totally useless.
Barry
On Sat, Jan 25, 2014 at 10:30 AM, JohnF <n29cx@ridgeviewtel.us> wrote:
> Barry, thank you for the response. The statement is on page 33 of the
> manual, second paragraph from the bottom. I have version 1-07. I am
> repeating below the answer I got from Dyna Vibe which I will have to read
> and re-read several times to try to understand it..
>
> One other question I have is just exactly what is the 'axis of the
> accelerometer' - is the vertical orientation of the unit, or some
> rotational position? I don't have a clue.
>
> Anyway, here is the answer from RPX...maybe you can help me clarify what
> they are telliing me.
>
>
> Fun question.
>
> It has to do with the timing of the signals and what the accelerometer
> =93feels=94 vs when it feels it with respect to the optical tach signal.
If the
> accelerometer is rotated 180 degrees then the signals are backwards. That
=92s
> why the solution flips (heavy vs light). If you are 90 degrees, then you
> will sense engine rotation in addition to vibration but the vibration wil
l
> be rotated 90 degrees and mixed with rotational vibration. So that=92s no
t
> really useful. If you are at 45 degrees, then you will sense rotation and
> vibration, but at a complex angle. So the math would be quite convolved.
> You would have to separate rotation, x vibration, and y vibration, which
> can=92t be done without more sensors to see what is going on.
>
> But I don=92t think you are looking for the literal answer to your
> question. So the actual answer is that you want the axis of the
> accelerometer pointing toward the center of rotation. If it isn=92t, then
you
> start sensing rotational vibration which isn=92t what you are looking for
.
> And if the sensor is backwards, then the math in the meter will be
> backwards. Which explains the heavy vs light statement
> Thanks again for your ehlp.
>
> John
>
>
> ----- Original Message -----
> *From:* FLYaDIVE <flyadive@gmail.com>
> *To:* rotaxengines-list@matronics.com
> *Sent:* Saturday, January 25, 2014 6:42 AM
> *Subject:* Re: RotaxEngines-List: Dyna Vibe Prop Dynamic Balancer Questio
n
>
> Hi John:
>
> I just read the original post.
> The answer is: It Can't!
> It has to be a misprint.
> I'm thinking it is easier to describe the accelerometer by identifying th
e
> cable as apposed to the mounting threads. Which will be hidden when mount
ed.
> Can you tell me what page that statement is on? And also what revision o
f
> the manual you are reading?
>
> If you really wanted to attempt something crazy, YES, you could make a
> mount that points the accelerometer way from the HUB (Center of the
> shaft). And that would give you the Lite Point, but, you would probably
be
> adding all sorts of erroneous vibrations due to the extended size of the
> bracket. I do not understand why Dyna Vibe did not simply have the featu
re
> of REVERSING the math or the output of the accelerometer. Or why they
> used such a large housing for the accelerometer; phones and iPads have
> surface mount accelerometers that are only 0.100" high and 0.250" square.
> Take that and pot it and you are done. Oh, well! It works.
>
> Barry
>
>
> On Fri, Jan 24, 2014 at 11:49 PM, JohnF <n29cx@ridgeviewtel.us> wrote:
>
>>
>> Maybe Roger Lee can answer this one:
>>
>> I purchased a Dyna Vibe dynamic prop balancer and the instructions seem
>> clear except for this statement:
>>
>> "If the accelerometer cable is pointing away from the center of the bub,
>> then the angle reported by the Dyna Vibe is the HEAVY spot (where to rem
ove
>> weight, or 180 degrees from where to add weight.) If you flip it so the
>> accelerometer cable is pointing toward the hub, then the reading will
>> indicate the light spot (where to ADD weight.)"
>>
>> Question: How can be orientation of the cable (not the accelerometer)
>> change what the reading angle means? (ie, heavy or light)
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=417551#417551
>>
>>
>>
>>
>>
>>
>>
>> ==========
>> -List" target="_blank">
>> http://www.matronics.com/Navigator?RotaxEngines-List
>> ==========
>> http://forums.matronics.com
>> ==========
>> le, List Admin.
>> ="_blank">http://www.matronics.com/contribution
>> ==========
>>
>>
>>
>>
> *
>
> href="http://www.matronics.com/Navigator?RotaxEngines-List <http://www.
matronics.com/Navigator?RotaxEngines-List>">http://www.matronics.com/Naviga
tor?RotaxEngines-List <http://www.matronics.com/Navigator?RotaxEngines-List
>
> href="http://forums.matronics.com <http://forums.matronics.com>">http:/
/forums.matronics.com <http://forums.matronics.com>
> href="http://www.matronics.com/contribution <http://www.matronics.com/c
ontribution>">http://www.matronics.com/c <http://www.matronics.com/c>
> *
>
> *
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