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From: AMuzi <am@yellowjersey.org>
Newsgroups: rec.bicycles.tech
Subject: Re: Electric Assist Tandem
Date: Thu, 2 May 2024 14:10:08 -0500
Organization: Yellow Jersey, Ltd.
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On 5/2/2024 1:50 PM, Zen Cycle wrote:
> On 5/2/2024 10:53 AM, Frank Krygowski wrote:
>> On 5/2/2024 9:00 AM, AMuzi wrote:
>>> On 5/2/2024 4:33 AM, zen cycle wrote:
>>>> On 4/30/2024 8:56 PM, AMuzi wrote:
>>>>> On 4/30/2024 7:21 PM, pH wrote:
>>>>>> I was driving along on my way home and noticed a a 
>>>>>> Jobst-yellow tandem of
>>>>>> some sort.
>>>>>>
>>>>>> I did a double take when I saw a Bosch-like motor bulb 
>>>>>> on the stoker's pedal
>>>>>> set!  I did not realize that there were electric 
>>>>>> assist tandems.
>>>>>>
>>>>>> By the time that realization set in it was too late to 
>>>>>> look and see if the
>>>>>> Captain's bottom bracket was motorized, too.
>>>>>>
>>>>>> I would not think that that would be the case, but you 
>>>>>> never know.
>>>>>>
>>>>>> pH in Aptos
>>>>>>
>>>>>> I think Yamaha and Shimno also make bottom bracket 
>>>>>> bulbs so no idea what it
>>>>>> was.
>>>>>>
>>>>>> I've seen several of the Ba-Feng (sp?) kit's of late 
>>>>>> as well.
>>>>>>
>>>>>> I'll try to do an un-scientific bike survey of what 
>>>>>> goes by sometime this
>>>>>> next month.
>>>>>>
>>>>>> pH in Aptos
>>>>>
>>>>> Yes battery assist tandems are a thing. As you note, 
>>>>> several motor formats just as bicycles generally.
>>>>>
>>>>> https://2022.santana-tandem.com/en/tandem/e-tandem
>>>>>
>>>>> There's no point in more than one motor in a drive 
>>>>> train. Or on both wheels for that matter.
>>>>
>>>> If we're talking about electric assist bicycles where it 
>>>> can still be propelled with legs in the event of a motor 
>>>> failure, yes. However some redundancy on vehicles 
>>>> without a 'back-up' is indeed practical.
>>>>
>>>> Turbine locomotives have motors on each drive wheel for 
>>>> exactly that purpose. If one motor fails, 7 more are 
>>>> generally enough to still do the job. If the turbine 
>>>> goes, they're still fucked though.
>>>
>>> Well, engineering is achieving a goal with efficiency of 
>>> limited resources; in the case of a tandem, weight, cost, 
>>> complexity and service over the system life.  There's 
>>> room for interpretation and weighing of those factors but 
>>> a single drive unit has been the overwhelming format.
>>>
>>> Conversely, for an airliner I agree that multiple engines 
>>> is a reasonable solution.
>>
>> Right. Benefits vs. detriments.
>>
>> Detriment of a single motor failure on a tandem: Riders 
>> have to pedal a bit harder. Versus detriment of engine 
>> failure on a single engine airliner: 100+ fatalities, 
>> years or decades of litigation and penalties, loss of 
>> future customers, etc.
>>
> 
> Boeing seems to have come to a slightly different conclusion.

?? Not about multiple engine airliners. Boeing hasn't made a 
single-engine commercial aircraft in my lifetime.
-- 
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971