[Land-speed] Multiple Engines

[John Burk]

In Bill Hoddinott's Burkland interview in the most recent issue of 
Bonneville Racing News they said they have Vibratec Fluidampers with 4 keys 
on each engines and a custom coupler made from "old Lenco parts" between the 
crankshafts .
John



> Sparky and others --
> My thought on this is that more torsional dampening in the form of a 
> better harmonic balancer might be what is called for.  Of course that is 
> aside from the issues of misalignment between the two engines and Dave's 
> suggestion to put in a 45 degree separation between the two engines to 
> smooth out the torque peaks. But be careful with this.  Such a proposal 
> can double the forcing frequency and put it closer to one of the new 
> vibration mode frequencies than you want.
> I do think that I'd want someone else's experience with the coupling of 
> two engines as an example to follow or a benchmark.  Lacking that I'd 
> spend some time relearning the methodology of torsional vibration analysis 
> I learned in my mechanical vibrations course some 50 years ago and 
> promptly forgot.  At the time the hot setup was a tabular calculation 
> protocol known as Holzer's method.  http://www.sdrl.uc.edu/book/Chap-5.pdf 
> Den Hartog, pg 197
> The right contact in the world of engine, turbine or other heavy rotating 
> machinery engineering could provide access to modern computerized methods 
> for torsional vibration analysis.  If you were to get into this your shop 
> capabilities would likely make it possible to determine actual spring 
> constants and moments of inertia that an engineer with the right software 
> would need to begin the calculations.
> Ed Weldon
>
>
> ----- Original Message ----- 
> From: "John Burk" <joyseydevil at comcast.net>
> To: "LandSpeed List" <Land-speed at autox.team.net>
> Sent: Tuesday, March 23, 2010 5:41 PM
> Subject: Re: [Land-speed] Multiple Engines
>
>
>>I think crankshafts are stout to raise the harmonic frequency and resist 
>>bending . For torque capacity think how small the transmission input shaft 
>>is .
>> John
>>
>>
>>
>>> List,
>>>
>>> When connecting two engines together at the crankshafts, what is the 
>>> best offset to use? My thought is that harmonics should be arranged such 
>>> that the rear crankshaft gets as little abuse as possible. Ideas?
>>>
>>> Thanks,
>>> Skip
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