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Author Topic: Principle of The Maudslay.  (Read 1950 times)


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Re: Principle of The Maudslay.
« Reply #25 on: October 07, 2020, 10:24:13 pm »

KBIO.....there is no problem.......

Members can set their preferences for the WEB site....'always translate to English'....and all posted text is auto translated from French to English :-))

Here is the posting by rookie on the subject  O0


Derek Warner

Honorary Secretary [Retired]
Illawarra Live Steamers Co-op


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Re: Principle of The Maudslay.
« Reply #26 on: October 08, 2020, 12:57:58 am »

Good evening.
Gear technology and Maudslay reverse are totally different. I found out when I looked for proper gears adjustment. %%

As astonishing as it is , I did not find  no documentation on Maudslay  either.
Fortunately ,  after a long time scratching our head to understand the principle and some discussion to find a volunteer to work it out, one of our engineers of our Forum : "Rookie" , a very good pedagogue, wrote a very smart paper to  describe the  principle of the Maudslay.
You can have it here :

That's probably the only paper , you'll find on it. But if someone can find another one, it would be greatly appreciated.
 I understand that it can be a problem for non French speaking people, but the drawings are clear enough and Google  translation will do the job.

Hope you find what you need and that answers you question.  :-)
Thanks for your interest.

Note. My small video helps to understand the basic , after it is just a question of machining down the proper Assy...... and get the right distance between two wheels centers ! %)
Thank you,
I have glance at the paper, the math and geometry takes me back to my college days. I will take a better look at it later.
Be wary of strong drink. It can make you shoot at tax collectors--and miss. Lazarus Long


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Re: Principle of The Maudslay.
« Reply #27 on: October 08, 2020, 12:43:29 pm »

This is a great explanation of how the Maudslay reversing gear operates and you should be commended for doing it.
Having said that there is one tiny mistake in your very first post where you stated: -
'the two shafts rotate in the same direction'

Assuming you mean the crankshaft and the eccentric shaft...This is not true with a 4 gear arrangement... they would actually rotate in opposite directions.
Apart from that tiny error the remainder of the article is excellent and very well explained, so very well done. O0 O0 :-))
Advancing the topic a little further... your article, as written, only relates to steam engines with simple line-on-line slide, or piston, valves where there is no steam lap or lead involved.
For engines that have valves with steam lap and/or lead then the eccentric would lead the crank by more than the 90degrees, stated in your article, in the direction of crank rotation and this could be as much as 120degrees... possibly more.

In such an engine, and many small model engines do have such valves, the Maudslay gear would need to move the eccentric shaft much more than the 180degrees described in your article.
It would need to move the eccentric shaft by 240degrees or more... i.e, 2 x the eccentric lead.
This can make the selection of the gears required, and/or shaft spacing, somewhat more complex especially where space might be restricted, however, the same basic principle discussed in your article would apply and use of the mathematical formulae provided in your attachment can easily solve such issues.
I only mention this since there may well be members of the forum who are, perhaps, considering converting their engines to Maudslay reversing gear, but would run in to problems if their engine had valves with steam lap.
Just thought it worth mentioning this and it is not intended as any form of criticism on your most excellent article. :-))
My very best regards.
Sandy. (ex ACS Engineering).



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Re: Principle of The Maudslay.
« Reply #28 on: October 08, 2020, 05:37:37 pm »

Thank you for the clarification! :-))

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