Author Topic: Isetta counter weight  (Read 6704 times)

Bob Purton

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Isetta counter weight
« on: October 01, 2010, 08:30:30 AM »
Thought I would enter this under a new topic as it has nothing to do with Jeremy Clarkson although we could try dropping one of these on him to see if it has the same effect as a piano on a Morris Marina.
The RHD counterweight weighs 21.5kgs and is about 7.5 inches wide.
A battery of this size would be too feeble to service an isetta.
« Last Edit: October 01, 2010, 08:32:43 AM by Bob Purton »

Chris Thomas

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Re: Isetta counter weight
« Reply #1 on: October 01, 2010, 08:50:40 AM »
Dear Bob

You are a mind of technical information.

However I note an interesting mixture of Imperial and Metric measurements in you note. If it is a German made Isetta should you be quoting all metric measurements, and if it is a pre 1974 British made Isetta should you be quoting all Imperial measurements?

We seem to be in that limbo stage where we should be using all metric dimensions, yet because the government are unwilling to expenditure some Imperial dimensions (MILES) still linger making both systems run together. I know older people find metric measure confusing and some young people find some Imperial measure confusing, but distance and weight seem to be the most used and confused of the measurements we use. What should the convention be in Rumcar?

Chris Thomas

steven mandell

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Re: Isetta counter weight
« Reply #2 on: October 01, 2010, 09:53:57 AM »
Thank you very much for taking the time to locate, weigh and post pictures of the counter weight.
Is there some way that I could see exactly where it was mounted in the car?  I'm interested in how the physics of its placement allowed a 47 lb weight to effectively counterbalance the combined weight of an Isetta's engine and driver.
You are right in that a conventionally constructed lead acid batterry of similar dimension would not be up to the task of servicing an Isetta.  However a batterry of that weight could service several of them.  So the confines of the acceptable locations where it needs to be placed to achieve the desired effect becomes critical in determining how practical it may be to attempt to duplicate the counterweight's beneficial effect with parts that would also serve another primary functional purpose for being in the car.
Actually Odyssey makes some very compact  rectangular long life gel type batteries with a tremendous cranking ability that are close to that size range.  It is also very usefull that they can be mounted at many angles without negative consequence.  I put one in my AZ-1 instead of the full sized Honda type batterry that it came with.  It both looks and works great- albeit at near $200 it is quite expensive.

steven mandell

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Re: Isetta counter weight
« Reply #3 on: October 01, 2010, 10:08:59 AM »
This just in- Wilkepedia says that the counterweight was 27 kg or approx. 60 lbs.

Bob Purton

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Re: Isetta counter weight
« Reply #4 on: October 01, 2010, 10:26:25 AM »
Ah, the plot thickens then, I lifted the 21.5 off the Isetta forum. It seems a little light to make much difference. I have an optima spiral tech battery in my Inter but none of these were around when the RHD was developed. I think its mounted inside at the sill just behind the left front wheel arch, you can see the sill shape in the weight.


Chris. Decimal inches were used in engineering for decades as alternative to imperial fractions before the uk had mm forced on it by the EU. Are you confessing to being one of the elderly confused?
« Last Edit: October 01, 2010, 10:33:49 AM by Bob Purton »

marcus

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Re: Isetta counter weight
« Reply #5 on: October 01, 2010, 01:17:41 PM »
I have my own unit of measurement, for estimating heights: the Double Decker Bus. Usually around 15 feet high. Imagine how many would stack up to be the same height as a building. Much more useful than yards or meters.
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Bob Purton

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Re: Isetta counter weight
« Reply #6 on: October 01, 2010, 01:45:25 PM »
What about smaller items? Corgi double decker buses?

marcus

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Re: Isetta counter weight
« Reply #7 on: October 01, 2010, 01:54:36 PM »
What about smaller items? Corgi No. 233 Heinkel Bubble Car
?
Just remember: as one door closes behind you, another slams in your face

Bob Purton

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Re: Isetta counter weight
« Reply #8 on: October 01, 2010, 02:01:25 PM »
How many of these to the foot?

marcus

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Re: Isetta counter weight
« Reply #9 on: October 01, 2010, 02:03:27 PM »
Hang on a mo, I will go and measure my ones.....
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marcus

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Re: Isetta counter weight
« Reply #10 on: October 01, 2010, 02:11:05 PM »
...

L:   4.8 to the foot
W:  9.6 to the foot
H:   9.8 to the foot

(counter-weight not included)


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Bob Purton

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Re: Isetta counter weight
« Reply #11 on: October 01, 2010, 05:53:10 PM »
Ah, I see you are using imperial decimal as well! We must be of the same age group of "engineers". What are you working on at the moment? I'm floor mounting a WW2 U boat telegraph, next week I'm on a Georgian Kaleidoscope. All fun!


marcus

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Re: Isetta counter weight
« Reply #13 on: October 01, 2010, 06:40:54 PM »
Ah, I see you are using imperial decimal as well! We must be of the same age group of "engineers". What are you working on at the moment? I'm floor mounting a WW2 U boat telegraph, next week I'm on a Georgian Kaleidoscope. All fun!

My godfather was a submarine Captain, we have great chats when we get together. His old sub (HMS Alliance) is now at the Gosport Submarine Museum. With his knowledge of subs and my interest in engines we figured out how the Sweedish Navy's non-nuclear subs are out-smarting the American ones. Making a Georgian Kaleidoscope sounds fun!  
I am getting another radical snare drum design ready for production, due to good interest at a drum show in Birmingham last w/e. You might recognise this Proper English Gentleman trying out my Busker Cajon drum kit. It's John Bly, furniture expert from BBC TV's Antiques Roadshow. There is already a you tube video of Al Murray / "The Pub Landlord"  playing it, (but spelled Al Murrey). Whatever next?!



Just remember: as one door closes behind you, another slams in your face

Bob Purton

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Re: Isetta counter weight
« Reply #14 on: October 01, 2010, 06:56:30 PM »
That sounds interesting Marcus. Our old drummer used to stick tea towels on his snare for some unknown reason! By the way, the kaleidoscope is a restoration job, a real one, not a prop this time.