[Fot] FW: Flywheel wt & crank harmonics -TR3/4

[Tony Drews]

I noticed it on track at 5600 rpm because it foamed the fuel in the 
float bowl, not because I actually felt it.

- Tony

On 5/21/2020 8:56 PM, Joe Alexander via Fot wrote:
> On my street TR4A, the harmonics came in about 2800 RPM and again at 
> 5600 RPM.
>
> It was an interesting sensation. Hard to describe.
>
> I never noticed it in any of the race engines.
>
> Joe Alexander
> 4505 Donald Dr
> Cedar Falls, IA 50613
> The-vintage-racer.com
> Gasketinnovations.com
> Cell:  319.464.4711
>
>
>> On May 21, 2020, at 6:14 PM, timmmurphh--- via Fot 
>> <fot at autox.team.net> wrote:
>>
>> 
>>
>> *From:* timmmurphh at gmail.com <timmmurphh at gmail.com>
>> *Sent:* Thursday, May 21, 2020 6:06 PM
>> *To:* 'TeriAnn J. Wakeman' <tjwakeman at gmail.com>
>> *Subject:* RE: [Fot] Flywheel wt & crank harmonics -TR3/4
>>
>> The weight of the flywheel will definitely affect the harmonic 
>> frequency.  The heavier the flywheel, the lower the harmonic 
>> frequency will be. The flywheel contributes a significant amount to 
>> the total rotating inertia due to its weight and that the weight is 
>> at greater radius than the other rotating masses.  Inertia increases 
>> as the square of the radius. It is not a linear function of the radius.
>>
>> An RPM of 5200 was mentioned as the harmonic resonance.  I had always 
>> heard that it was more like 6300 RPM.  I have never seen a 
>> calculation for it. It would be complex.  Note that lighter pistons 
>> and connecting rods would tend to lower the harmonic frequency as 
>> they would reduce the inertia in the engine.
>>
>> Tim Murphy
>>
>> *From:* Fot <fot-bounces at autox.team.net 
>> <mailto:fot-bounces at autox.team.net>> *On Behalf Of *TeriAnn J. 
>> Wakeman via Fot
>> *Sent:* Thursday, May 21, 2020 2:44 PM
>> *To:* FOT <fot at autox.team.net <mailto:fot at autox.team.net>>
>> *Subject:* [Fot] Flywheel wt & crank harmonics -TR3/4
>>
>> Something I have wondered about for years.
>>
>> Does the weight of the flywheel affect the RPM and intensity of 
>> harmonics inherent in a TR3/4 stock crank? I've never found an answer 
>> to that question.
>>
>> TeriAnn
>>
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>
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