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 Dead or Alive diesel

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David Grantham




PostSubject: Re: Dead or Alive diesel   Mon Oct 29, 2012 9:45 pm

Anton, I have built 3 prototype test beds each with a newish four stroke and all have failed due to either insufficient gearing or structural failure of the gearbox.

I could not start the 4 stroke without gearing using a 24v 11 pole (950?) motor so I would be most surprised if your 850 would work. The other big issue is the power surge once every 4 cycles causes massive stresses on the gears or gearbox.

Maybe a well worn 2nd hand 4s is better than a newish one ?
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antonr91



Location : south-east England

PostSubject: Re: Dead or Alive diesel   Mon Oct 29, 2012 10:03 pm

Okay now i understand a little better. So what has become of your first live diesel then?

Hmmm well youve tried it so your probably right. But i still want to try myself, and i hope your right about the second hand engines....
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Carl Hibbs
Admin


Location : Haute Normandie - visitors welcome

PostSubject: Re: Dead or Alive diesel   Tue Oct 30, 2012 7:25 am

There are other people who are starting 4 strokes using dc motors but these people; Jerry Hyde and Wada Works for example are using precision engineering and components to match.

With respect, what we are doing here (including me) is a more 'DIY interpretation'.

The MFA Torpedo 850 size motor is only just sufficient to turn over a .15 2 stroke engine with a direct coupling and fully charged 12v 8Ah battery.
I doubt very much indeed whether it will move even the smallest 4 stroke engine.

If you're passionate about having a 4 stroke I think there is a need to be passionate about getting the engineering precise.

David's already done the donkey work. study

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antonr91



Location : south-east England

PostSubject: Re: Dead or Alive diesel   Wed Oct 31, 2012 10:42 am

Yes, i agree Carl, which is why i am taking the time and watching and reading all posts that David does, as he seems to be finding out from his trial and error tests what works and what doesnt. This is why i am in no rush to go and buy a 4stroke onc David has mastered his machine, im sure (well i hope) Wink he shall share with all.

I am in now way comparing my machines to their standard and I myself will be the first to admit the my impatience and excitement gets the better of me at most times and i always end up rushing each project....but its just a bit of fun for me and the main thing is i enjoy it, and by the amount of time, money and sweat that everyone shows to spend on this forum, i would say it must be a thoroughly enjoyable experience for all cheers

I would have agreed with the MFA only having enough power to start small 2S as if i ever flooded mine, it would not turn, until my battery ran out on sunday, and the clubs small 12v 7Ah lead acid failed as well, and i actually started the loco of my car battery (not safe and not advising) but the power behind it was immense Razz

On another note does anyone have any knowledge about ASP engines? good? bad? I think they are Jap made?

http://www.justengines.co.uk/acatalog/ASP_Aero_4_Stroke.html
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David Grantham



Location : Midlands, England

PostSubject: Re: Dead or Alive diesel   Wed Dec 26, 2012 3:09 pm




Final version using a belt drive with a scooter dc and an OS 30FS nitro. Worked well for about 8 starts and then the belt shredded.

My conclusions so far are:-
- It is very difficult to use a 4 stroke on a live diesel. Pull starts are not generally available and forces involved in using electric starter/generator are very severe.
- The belt drive has a number of attractions. It allows gearing, noise reduction and imprecise alignment and is also expendable. The one I used was 9mm wide and 3mm between teeth.
- I will see if I can obtain a stronger and more rugged belt maybe up to 18mm wide. Presumably the scooter belts would be too long to be practicable.
- Only remaining option will be to try a large Oldham coupling. This does not allow gearing but can be slightly tolerant of minimum misaligment and has a fusible disc which avoids catastophic failure and is replaceable in cost terms.

This project has been great fun and totally unsuccessful so far, and as such has been a great learning curve. The sobering thought is that had I spent the same amount of time as I have on the electric start 4 stroke but on the standard Hibbs model 2 stroke then I would have built 3 or 4 working models by now. Hopefully time for that later.
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David Grantham



Location : Midlands, England

PostSubject: Re: Dead or Alive diesel   Wed Dec 26, 2012 3:31 pm




And another picture to prove that no woodscrews were injured in this experiment.
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Carl Hibbs
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Location : Haute Normandie - visitors welcome

PostSubject: Re: Dead or Alive diesel   Wed Dec 26, 2012 4:13 pm

David Grantham wrote:


This project has been great fun and totally unsuccessful so far, and as such has been a great learning curve. The sobering thought is that had I spent the same amount of time as I have on the electric start 4 stroke but on the standard Hibbs model 2 stroke then I would have built 3 or 4 working models by now. Hopefully time for that later.

I don't agree with the totally unsuccessful part. It has been a success in dealing with the problems of 4 stroke engines.

One has to say David from the pictures that it looks mightily impressive. If there is any degree of misachievement then it's not through lack of workmanship and effort. If was in your position I would probably still persevere having come so far. I would certainly keep this as a test bed. I take back what I said about 'tractor technology'. Embarassed

I have been doing some more testing today too. Details later on yet another diesel thread.
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KleineDicke



Location : Deep in the Heart of Texas (Houston)

PostSubject: Re: Dead or Alive diesel   Wed Dec 26, 2012 9:59 pm

Have you tried a vacuum cleaner belt? They seem rather stout and certainly take a lot of abuse. Might be too long, though. I agree with Carl; your project, while certainly disappointing after all your work, was not a complete failure.

_________________
Bill Wray

"It is one of the happiest characteristics
of this glorious country that official utterances are invariably
regarded as unanswerable."
-Sir Joseph Porter, First Lord of the Admiralty (HMS Pinafore)
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antonr91



Location : south-east England

PostSubject: Re: Dead or Alive diesel   Tue Mar 26, 2013 5:22 pm

Hi David

Where could one source those metal square bars that use use the in the picture above, for mounting your engine to that metal plate? Very Happy
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PostSubject: Re: Dead or Alive diesel   Today at 6:04 am

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