Author Topic: Roy's Little Engine  (Read 48596 times)

Offline Alyn Foundry

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Re: Roy's Little Engine
« Reply #60 on: December 23, 2017, 02:13:17 PM »
You're welcome John.

Looking forward to seeing your progress here if possible?

Here's what I was writing about in my previous post.

<a href="https://www.youtube.com/watch?v=ZMH21SK_BN8" target="_blank">http://www.youtube.com/watch?v=ZMH21SK_BN8</a>

Cheers Graham.

Offline Manorfarmdenton

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Re: Roy's Little Engine
« Reply #61 on: December 23, 2017, 06:43:47 PM »
Progress to date.  I made the rocker arm from flat stock as you can see.
John Fearnley

Offline Alyn Foundry

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Re: Roy's Little Engine
« Reply #62 on: December 24, 2017, 11:56:18 AM »
Hi John.

Yes, I see and also a flat push rod too.

That’s an early kit, raised triangle with raised lettering on the water hopper and no easy means of securing the sub base. That’s an all Rhuddlan Iron kit. Before 2000, the year they closed.

I’d like to take this opportunity to wish you and everyone at MEM a very happy Christmas, hope for the future.

Cheers Graham.


Offline Manorfarmdenton

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Re: Roy's Little Engine
« Reply #63 on: December 24, 2017, 02:53:36 PM »
Thank you Graham.  The same to you and to everyone else on MEM.  John.
John Fearnley

Offline RayW

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Re: Roy's Little Engine
« Reply #64 on: December 25, 2017, 09:05:31 AM »
Seasons greetings to all from me too. Have a great Christmas and a Happy and busy New Year.

Ray
Ray

Offline Manorfarmdenton

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Re: Roy's Little Engine
« Reply #65 on: January 05, 2018, 11:06:35 PM »
Having spent some time in the workshop in the last few days, I now have the con rod finished, complete with bronze big end shells, and bronze main bearings,  It was a touch tight to start with but a couple of minutes spinning with cordless drill got it turning relatively freely.  Its nice to see the flywheels run absolutely truly, even with gib-head key knocked in. 
Since the governor bits and pieces are relatively simple, thoughts have turned to the electrics.  My Red Wings both have trembler coil and pickup as per the drawing, but for the RLE I thought I'd use Hall effect switch and CDI setup from Minimag, especially since its a freelance engine design.  Its simple to mount it on the far side from the timing gears, running at engine speed and wasting a spark.  Does that sound sensible?  John.
John Fearnley

Offline Jasonb

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Re: Roy's Little Engine
« Reply #66 on: January 06, 2018, 04:56:44 PM »
That should work OK and there is quite a bit of room on that side to play with.

The first Hit & Miss that I made had it on that side, the hall sensor fixed into a disc that clamped onto an extended bearing so that you could advance and retard the timing and then a disc fixed to the crankshaft with a grub screw to carry the magnet. It's the two brass discs just above the piston in thiis pic




Offline Manorfarmdenton

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Re: Roy's Little Engine
« Reply #67 on: January 06, 2018, 06:24:18 PM »
Thanks for that Jason.  I can clearly see the bits you refer to.  I'm slightly confused, though, that the kit I was intending to buy from Minimagneto would have a sensor that measures 25mm long I think.  Yours appears to fit into a groove in the split disc, and is tiny?  Perhaps I'm looking at the wrong sensor on their website?
John Fearnley

Offline Jasonb

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Re: Roy's Little Engine
« Reply #68 on: January 06, 2018, 06:35:09 PM »
Hall sensors are generally about 6mm square by 2mm thick and will fit into a milled slot. What I think you are looking at is the sensor AND the heat shrink insulation where the 3 wires are soldered to the sensor. Red bit are the end is sensor, blue heatshrink

Offline Jasonb

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Re: Roy's Little Engine
« Reply #69 on: January 06, 2018, 06:56:21 PM »
This shows it better on mine with the flywheel removed

You can just see the three contacts from the sensor where I have slid the heat shrink back so the actual sensor will easily fit in the slot



And the hole in the other ring for a magnet



Jo, if you have not got as far as making the bearings for yours then it would be worth making the one on this side 6.35mm longer if you want to mount a hall sensor in teh same way.

Offline Alyn Foundry

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Re: Roy's Little Engine
« Reply #70 on: January 06, 2018, 07:03:36 PM »
Hi John.

Its been a busy day and I thank Jason for answering a question that I wouldn’t have been able to.

I’m totally unfamiliar with electronic ignition systems available for models, I’ve stated many times that I prefer the “ Old school “ approach. Good old points and coil!!

I recall one customer using a small magnet let into the flywheel rim and the sensor was made to adjust side to side for advance and retard.

Cheers Graham.

Offline Bluechip

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Re: Roy's Little Engine
« Reply #71 on: January 06, 2018, 07:05:17 PM »
Here's one, a A1120EUA-T Hall-Effect switch. Au naturel

Hope the pic attaches.

Dave

Offline Manorfarmdenton

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Re: Roy's Little Engine
« Reply #72 on: January 06, 2018, 11:40:55 PM »
Many thanks Jason, Graham and Dave.  I'm happy that I now know what I have to do.
Jason - very good advice to Jo.  I have already made bronze bushes for the main bearings and now need to make another elongated one as I think you method of mounting the sensor is excellent.  How do I hold the sensor in the slot - epoxy?  Thanks for the photos too.  The only downside is that looking at them makes me wonder whether to give up!  My machining or photography isn't in the same league!
Graham - like you I don't know anything about electronic ignition on models, but am interested to give it a try.  This small stuff is a bit of a novelty for me - a week or two ago I was fitting new fuel pumps to my 325HP Cat Challenger 75 which was having starting problems in the cold weather.

John.
John Fearnley

Offline Manorfarmdenton

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Re: Roy's Little Engine
« Reply #73 on: January 06, 2018, 11:51:08 PM »
Jason - I have just had a mail from Julian at Minimag Co (whose kit I want to buy) advising insulating the sensor from the engine frame in case the HT earth becomes detached, in which case the HT volts would return to earth via the sensor, burning it out.  Presumably that hasn't been a problem for you?  I don't really see why it should be an issue if the lead is attached properly in the first place?  John.
John Fearnley

Offline b.lindsey

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Re: Roy's Little Engine
« Reply #74 on: January 07, 2018, 12:17:43 AM »
John, over here Roy School supplies his with a plastic case into which the hall sensor and leads (with insulation) fit. It's a bit bulkier, but adds a level of protection too. The picture shows the sensor in this case on my Tiny build.

Bill

 

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