Today's Message Index:
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1. 08:32 AM - Re: Re: 912 UL vibration (Richard Girard)
2. 09:13 AM - Re: Re: 912 UL vibration (FLYaDIVE)
Message 1
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| Subject: | Re: 912 UL vibration |
Roger, Barry, While adding a washer will certainly work why not paint the
prop tips and add more paint on the light blade? For a pusher, especially
one on a two stroke powered aircraft you will get a fair amount of oil and
dirt that sticks to the blades and affects the balance. Part of my yearly
maintenance is to clean and repaint the prop, test the balance, and use the
tip paint to get the prop to Rotax specs for a new prop, less than half a
gram of imbalance.
I also recommend Balance Masters prop dynamic prop balancers. They are very
light and really do the job of getting rid of that last little bit and
countering for bug and oil buildup during flight.
Rick Girard
On Sat, Oct 13, 2012 at 9:43 AM, Roger Lee <ssadiver1@yahoo.com> wrote:
>
> Hi Barry,
>
> Unfortunately there are many different prop mounts that people use on
> their planes. Some have backing plates and spinners, prop hub extensions,
> ext...
> If they don't have a backing plate then you may be stuck with putting a
> large washer on one of the prop mounting bolts. If you do that it could
> take a little more weight because it is closer to the center of mass. Or
> you could get him to put a backing plate and spinner on his plane and would
> benefit from better air flow and the balance. With the backing plate you
> can then move the weight out farther from the center.
> Just so many of you know as a tidbit fact. It is more important and
> affects the flow of air to have a spinner on a pusher over a tractor prop.
> The air flow is affected more and in a positive way.
> Which is funny because we seem to always put spinners on tractor props.
>
> --------
> 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=385246#385246
>
>
--
Zulu Delta
Mk IIIC
Thanks, Homer GBYM
It isn't necessary to have relatives in Kansas City in order to be unhappy.
- Groucho Marx
Message 2
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| Subject: | Re: 912 UL vibration |
Rick:
Painting the prop will work for STATIC balancing of the prop. But, what
happens when the heavy point is at a rotational degree location tat is out
in space. NO PHYSICAL location to add or remove weight? Not all the
balancing is of the prop. Things like Engine, Spinner and Mounts
contribute to vibration. AND how much paint is required? What happens
when the paint is worn off? Slow changes in vibration is
not noticeable over long periods of time... The body just gets use to it.
The plane and insturments on the other had react to it - Shortened life.
The idea of oil on the prop causing imbalance is very possible but also
very arguable. Since the prop is spinning wouldn't there be an equal
amount of oil spray on each blade? Who know, who cares... Just wipe the
prop down after each landing.
Balance Masters - This is another one of those theories/myths that has not
been truly proven or disproven. I did a little balancing experiment at
work with the same idea of a movable mass (mercury) and found it did NOT
always balance out, it was 2 time yes, 15 times no. And my testing was
Mercury Vs Accelerometer. Way too many variables to get repeated results.
The better way of doing a moving weight balance system is a Washing
Machine. Check it out - Pretty cool ideas there.
Barry
On Mon, Oct 15, 2012 at 11:31 AM, Richard Girard <aslsa.rng@gmail.com>wrote:
> Roger, Barry, While adding a washer will certainly work why not paint the
> prop tips and add more paint on the light blade? For a pusher, especially
> one on a two stroke powered aircraft you will get a fair amount of oil and
> dirt that sticks to the blades and affects the balance. Part of my yearly
> maintenance is to clean and repaint the prop, test the balance, and use the
> tip paint to get the prop to Rotax specs for a new prop, less than half a
> gram of imbalance.
> I also recommend Balance Masters prop dynamic prop balancers. They are
> very light and really do the job of getting rid of that last little bit and
> countering for bug and oil buildup during flight.
>
> Rick Girard
>
> On Sat, Oct 13, 2012 at 9:43 AM, Roger Lee <ssadiver1@yahoo.com> wrote:
>
>> >
>>
>> Hi Barry,
>>
>> Unfortunately there are many different prop mounts that people use on
>> their planes. Some have backing plates and spinners, prop hub extensions,
>> ext...
>> If they don't have a backing plate then you may be stuck with putting a
>> large washer on one of the prop mounting bolts. If you do that it could
>> take a little more weight because it is closer to the center of mass. Or
>> you could get him to put a backing plate and spinner on his plane and would
>> benefit from better air flow and the balance. With the backing plate you
>> can then move the weight out farther from the center.
>> Just so many of you know as a tidbit fact. It is more important and
>> affects the flow of air to have a spinner on a pusher over a tractor prop.
>> The air flow is affected more and in a positive way.
>> Which is funny because we seem to always put spinners on tractor props.
>>
>> --------
>> 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=385246#385246
>>
>>
>>
>>
>>
>>
>>
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>> -List" target="_blank">
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>> ==========
>> le, List Admin.
>> ="_blank">http://www.matronics.com/contribution
>> ==========
>>
>>
>>
>>
>
>
> --
> Zulu Delta
> Mk IIIC
> Thanks, Homer GBYM
>
> It isn't necessary to have relatives in Kansas City in order to be unhappy.
> - Groucho Marx
>
>
> *
>
> *
>
>
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