Author Topic: OMG.... Not another one!  (Read 885 times)

Offline Alyn Foundry

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OMG.... Not another one!
« on: August 21, 2020, 07:01:41 PM »
Yes, perhaps becoming a little boring? But this is CHUK 3 MK 2.

The CHUK engine was designed to be built from Iron castings and of simple construction. A " Modular " approach was chosen so that different engines could be made using the same, fundamental parts. They were going to be cast in large volume in the Far East, but with my health having failed, quite drastically, the project was cancelled.

I'm not going to bore you with the machining aspects as they have been covered admirably  well by Chipmaster, Jo and Twizseven in the various threads listed below.

http://www.modelenginemaker.com/index.php/topic,5124.0.html

http://www.modelenginemaker.com/index.php/topic,9485.0.html

http://www.modelenginemaker.com/index.php/topic,9743.0.html


CHUK 3 was an horizontal design using a modified R.L.E. sub base with the addition of a single main bearing pedestal. The main bearing carrier was made as a separate part to help reduce the headaches of " in situ " line boring. A simple, right angled casting was done to secure the cylinder to the bed.
Otherwise CHUK 3 used the same set of castings for its construction as in the flywheel, crank, cam and cylinder head.

Work commenced on CHUK 3 before the year 2000 as the castings were from the Rhuddlan foundry. Being such a simple design the engine came together very quickly and test runs were conducted. This was when the disappointment set in!

I had continued with the " Stanley knife blade " shutter scheme across the now, vertically aligned flame port. This was, in effect its Achilles heel. The Gods had to be smiling, the winds favourable your tongue in the right place kind of engine. The video below was shot on a day when all the Runes were right! Needless to say CHUK 3 got shelved.



Having learned a few more tricks since then and the only engine built was sitting in the small power section at the Anson Engine museum, I decided to build another one from some leftovers. I was reminded of their origins by, strangely enough, the smell. Rhuddlan's Iron has a very distinct odour as its being machined, took me right back to my " hay days " of the business.

I decided to incorporate a " rotary valve " that I had used on A.L.F. see video.


This design would put the flame port underneath for better coverage. The, now famous " Chipmaster valve " was used in conjunction with my discovery of coil springs rather than flat ones used earlier. This meant a different cylinder head design was needed to carry the central 12 mm coil spring. The exhaust now exits by nine 5 mm holes drilled in a circle near the outside diameter.

I think the video tells you the rest of the story, CHUK 3 MK 2 actually works!!


Cheers Graham.


« Last Edit: August 21, 2020, 07:06:57 PM by Alyn Foundry »

Online crueby

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Re: OMG.... Not another one!
« Reply #1 on: August 21, 2020, 07:05:28 PM »
They must be breeding out in the shed!   :naughty:

Offline Jasonb

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Re: OMG.... Not another one!
« Reply #2 on: August 21, 2020, 07:28:20 PM »


............................CHUK 3 MK 2 actually works!!



And rather well at that :)

Is the rotary valve a slot or hole sin a rod or two flats machined on either side to form more of a butterfly type valve?

Watch out Jo's little helper will be wanting one of those.

J

PS Now the rims are done that's one BIG flywheel!

Offline Jo

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Re: OMG.... Not another one!
« Reply #3 on: August 22, 2020, 07:53:27 AM »
 8) Other than the risk of getting a sooty engine, that does look to be the answer.

I am sure his Lordship will be attending the show and if he sees it and realises it is made from castings  :facepalm:

Jo
Enjoyment is more important than achievement.

Offline Alyn Foundry

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Re: OMG.... Not another one!
« Reply #4 on: August 22, 2020, 12:04:15 PM »
Hi Jo.

Yes, that was a quick, and definitely dirty third run for the engine.

Methyated spirit would be a clean alternative but I've always been wary after the " fire fiasco " at a show in Oswestry many years ago, when the fuel tank burst into flames.

Jason.

The rotary valve is just a slot milled centrally along a piece of highly polished 12 mm Silver Steel. I used 13.7 mm Brass to keep the valve from " floating " out.

Pleased to read of your flywheel progress, I'm looking forward to seeing the fruits of your labours.

Cheers Graham.

Offline Alyn Foundry

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Re: OMG.... Not another one!
« Reply #5 on: January 13, 2021, 07:55:19 PM »
Well....

Whilst Jason and I were developing CHUK " V " work was also being done to improve the rather messy burner arrangements for CHUK 3.

A rather cheap hiker stove became the basis for a new " clean " burner for the under slung rotary valve engine, I think the video explains the rest....


Cheers Graham.

Offline Jasonb

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Re: OMG.... Not another one!
« Reply #6 on: January 13, 2021, 08:05:35 PM »
That's wasting a lot less gas than when you had the stove burner under it, should also make for a longer running time as there is less flame heating the cylinder :)

Look forward to seeing the twin burner version on V by the end of the week :stickpoke:

Offline Alyn Foundry

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Re: OMG.... Not another one!
« Reply #7 on: January 14, 2021, 12:35:52 PM »
Reads like a challenge Jason.  ;)

Yes, the cylinder does heat up far slower but the difference in valve timing is quite noticeable between the clean and dirty flames.

I've just been in touch with the foundry and they decided not to send the CHUK V flywheel casting out so close to Christmas. I'm hoping to receive it next week, this will, in effect finish the project.

Cheers Graham.