Author Topic: CHUK " V "  (Read 711 times)

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1192
  • North Wales, Great Britain.
CHUK " V "
« on: November 20, 2020, 03:50:52 PM »
CHUK " V "

The Vee Twin, my liking for them possibly inherited? Dad drove and competed with Morgan three wheelers through the late 40's and early 50's fitted with engines from Anzani, JAP and Matchless, he loved them.

As a natural progression my CHUK range developed starting with a vertical then an inverted vertical and onto a horizontal. The engines were conceived on a modular basis so the same patterns and castings could be used over and over keeping production costs to a minimum. CHUK 4 ( an inverted vertical twin cylinder ) is still in part built form and will be finished when it's finished.

The Vacuum, flame licker/gulper engine is one of the simplest to build and equally easy to run. This was the main reason for its choice as a build project aimed at novice entry level to model engineering.

I mentioned the concept to Jason Ballamy whilst he was helping me with some patterns for my long term project, the Brayton Readymotor. Within a couple of days I received 3D images of my concept via email. Several more interchanges later and CHUK " V " became a reality. To see a pencil sketch become wood then metal in a fraction of the time it used to take shows the amazing power of CAD and CNC . CHUK " V " ? Well the Roman numeral for five is the letter " V " quite an obvious choice really. Whilst the concept is mine due credit must go to Jason who has virtually designed the rest of this engine.

The number 5 will predominate in this particular build and my choice of using Aluminium instead of good old cast Iron is based upon a chance sighting of a Stuart Turner " bottle " steam engine. I was really taken by both the shape and nicely polished surfaces. Cast Iron is still in predominance as both air cooled cylinders, pistons and heads will be made from it. The engine will also use my recently improved " rotary " valve and
" Chipmaster " exhausts.

What will follow is our documented collaboration of a new engine from the Alyn Foundry stable. Some Iron castings are still on order but the Aluminium crankcases arrived yesterday from my dear friends at Madeley Brass. Hopefully we'll see a working Vee twin vacuum engine for our efforts or perhaps a nicely polished door stop? Time will tell....

Now over to Jason....

Online Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 13816
  • Hampshire, england.
Re: CHUK " V "
« Reply #1 on: November 20, 2020, 04:01:26 PM »
 :thinking:
Enjoyment is more important than achievement.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1192
  • North Wales, Great Britain.
Re: CHUK " V "
« Reply #2 on: November 20, 2020, 04:41:29 PM »
:thinking:

I know, Jo....

Who'd have thought? Jason making patterns?

He's damn good at it too!

Oh, I forgot to mention the flywheel.... It's a rather " pretty " IRON one too.

Online Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 13816
  • Hampshire, england.
Re: CHUK " V "
« Reply #3 on: November 20, 2020, 04:58:09 PM »
:thinking:

I know, Jo....

Who'd have thought? Jason making patterns?

He's damn good at it too!


Jason is irrelevant  :lolb:  I am thinking about if a Vee twin flame licker would feel right  :thinking: .


I don't like the Stuart Vee twins: They seem to be a model designed to meet a current trend of men who wished they owned a big Vee twin motorcycle. Having owned Vee twins I can confirm I sold mine and kept the Norton  :embarassed:

Jo
Enjoyment is more important than achievement.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1192
  • North Wales, Great Britain.
Re: CHUK " V "
« Reply #4 on: November 20, 2020, 06:48:08 PM »
Well....

If I'd have been the remotest bit interested in motorcycles it would have been a Brough for me Jo.

A tangle between me a Honda CD175 and a rose bush on my garden path put me off two wheel transport, permanently. It didn't stop me acquiring a rather nice 1925 350 cc BSA flat tank though. The riding was always undertaken by Martin when taken to the Steam rallies.

I'm sorry you feel the way you do about the model but I happen to like Vee twins.

Cheers Graham.

Online Jasonb

  • Full Member
  • *****
  • Posts: 7573
  • Surrey, UK
Re: CHUK " V "
« Reply #5 on: November 20, 2020, 06:58:12 PM »
It's all Grahams fault, he made me do it honest :LittleDevil:

At the end of August Graham sent me that napkin sketch with a very basic spec, I liked the idea and asked him for a few dimensions of the cylinder castings and while waiting had come up with a basic design using enlarged 3D models of many of the parts from my version of the CHUK range "CHUKY"



After several exchanges of e-mails sending screen shots of the evolving engine to Graham for comment a final design had been agreed by the end of September with a one piece crankcase that would carry the overhung crank on one side and have a cover plate on the other side bearing the CHUK V name with the intention that this could be buffed up to look like the Stuart BB that Graham had seen. It will use a modified version of the existing cam profile that will be housed within the crankcase with tapped guides set into the top of the crankcase. The builder will have the option to machine 5 holes in the flywheel side of the casting to make it possible to watch what is going on inside.



As Graham mentioned the existing cylinder castings can be used with some machining of the end to allow them to be fixed to the crankcase flanges with yes you guessed it 5 studs and nuts. The head castings will incorporate a boss to house the exhaust spring and may be retained with studs and nuts or with counterbored holes for screws



The plate that closes up the crankcase will have recessed letters allowing the builder to buff up the surface and inlay the writing with their chosen colour of paint, red or black seem likely candidates. Once again the cover will have 5 fixings and Graham likes the idea of the recessed screws to match the look of that bike engine that Graham lusts after.



For those that are wishing they had not sold their old bike I did sketch out a possible alternative head and exhaust option



Or there may even be other possibilities using the same crankcase casting



What will follow is a few posts showing the pattern making process and if you are good boys, girls and elephants Graham may then show you some shiny castings :)



Offline Twizseven

  • Full Member
  • ****
  • Posts: 493
Re: CHUK " V "
« Reply #6 on: November 20, 2020, 09:19:41 PM »
This looks interesting. Need to get few others done first.

How long before Surus asks for a set.

Colin

Offline Dave Otto

  • Full Member
  • *****
  • Posts: 3877
  • Boise, Idaho USA
    • Photo Bucket
Re: CHUK " V "
« Reply #7 on: November 21, 2020, 12:24:35 AM »
Interesting project guys!
Will be fun to watch.

Dave

Online Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 13816
  • Hampshire, england.
Re: CHUK " V "
« Reply #8 on: November 21, 2020, 08:00:27 AM »
How long before Surus asks for a set.

He is more interested in the boxes of Snickers that turned up the other day at the moment  ::)

Jo
Enjoyment is more important than achievement.

Online Jasonb

  • Full Member
  • *****
  • Posts: 7573
  • Surrey, UK
Re: CHUK " V "
« Reply #9 on: November 21, 2020, 10:36:07 AM »
He is more interested in the boxes of Snickers that turned up the other day at the moment  ::)

I doubt he will have any problems finishing them :LittleDevil:

I thought you liked V twin's Jo, does not seem long ago that I drew this out and you said "You know how much I love Hoglets, its on my build list along with another couple" At least you seem to be able to get the flame lickers running unlike any four-strokes.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1192
  • North Wales, Great Britain.
Re: CHUK " V "
« Reply #10 on: November 21, 2020, 11:50:14 AM »
Good morning Jason.

I hadn't thought about alternative uses for the crankcase myself but obviously with the CHUK range the
 " overhung " crank might be a little flimsy. We would have to incorporate an additional boss in the front cover to accommodate a bearing so a more conventional " full " crank could be used.

The five holes in the rear of the crankcase serve a way more important function than just observation, without them the case would be effectively sealed. Because these types of engine function using the power of atmospheric pressure if a vacuum was created in the cylinder with a sealed case you'd get equilibrium.

Cheers Graham.

Online Jasonb

  • Full Member
  • *****
  • Posts: 7573
  • Surrey, UK
Re: CHUK " V "
« Reply #11 on: November 21, 2020, 01:21:47 PM »
I was thinking more along the lines of machining the whole end off and then having matching covers each side, not sure if the cam would stay inside of have to be exposed like the Hoglet is at the moment. Only a couple of engines to go before you can join 4 crankcases together for CHUK Version8 ;)

Talking of alternate uses for castings don't you think a couple our nice new iron ones would be about the right weight and diameter for a Heinrici :thinking:

Will post a bit more about the pattern making tonight.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1192
  • North Wales, Great Britain.
Re: CHUK " V "
« Reply #12 on: November 21, 2020, 01:57:36 PM »
Hmmm, I don't particularly like repetition of components Jason so no, two is enough.... However a 5 cylinder " rotary " would be an interesting challenge wouldn't it?

Although our " Iron ones " are very pretty to look at I think they'd be totally inappropriate for Jo's Heinrici as it's meant to be a replica. I recently found the original flywheel patterns but they've gone astray after a recent " tidy " session. I do, however have a pair of fully machined flywheels on a disassembled Reeves version. These could be used as patterns at a pinch.

Looking forward to your next instalment.

Cheers Graham.

Online Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 13816
  • Hampshire, england.
Re: CHUK " V "
« Reply #13 on: November 21, 2020, 02:43:52 PM »
I thought you liked V twin's Jo, does not seem long ago that I drew this out and you said "You know how much I love Hoglets, its on my build list along with another couple" At least you seem to be able to get the flame lickers running unlike any four-strokes.

There was a time when liked the idea of being married as well   :paranoia:

The only engines that I have built that have not run when tried have been ones that had a liking for damaging thumbs  ::)

Jo
Enjoyment is more important than achievement.

Online Jasonb

  • Full Member
  • *****
  • Posts: 7573
  • Surrey, UK
Re: CHUK " V "
« Reply #14 on: November 21, 2020, 07:51:12 PM »
Now that I had the engine drawn out it was time to start converting the drawings to ones that could be used as patterns. Starting with the crankcase I made a copy of the file shown in my post above and then suppressed all the features that I did not need such as bearing hole, holes in the flanges for the cylinders to locate in, etc. I then added machining allowances where needed as well as draft angle so that the patterns could be pulled from the sand.



I decided it would be easiest to start by cutting two matching "halves" and then add the endplate with bearing boss as a third part so did a simple "extrude - cut" which left me with half a crankcase. I find that sometimes Alibre can have problems adding fillets to some internal corners once you start having more complex shapes joining at odd angles so left most of the fillets off the pattern file but will make use of the shape of the cutter to include them on the actual pattern.



The file was then exported to Fusion 360 to do the CAM, I ended up with 3 separate strategies to produce the shape. Firstly an adaptive clearing one which is basically a roughing out pass leaving 0.5mm stock which was done with a long shank 4-flute carbide cutter at 5000rpm with a feed of 450mm/min taking most of the material off with a 5mm high by 1mm deep cut then just stepping up 1mm for the fine roughing which can better be seen on the next but one photo. The blue lines are the path that the centre of the end of the tool follows when cutting the yellow are where it is moving between cuts



Next using the same tool and speeds but with a 4mm stepover the flat face had the final 0.5mm removed. you can see the stepped finish that the adaptive cuts left better in this photo as the tool paths don't get in the way.



Finally a long shank 4-flute 6mm carbide ball nose cutter was used with a "steep and shallow" strategy that was set with a fine 0.33mm stepover or "scallop" between cuts again running at my max speed of 5000rpm but feeding a bit faster at 550mm/min



This image shows how F360's simulator will leave the finished part, the bright green areas are where it has cut to the drawn surface, the blue is material it has not removed which you can see is basically all the places where I wanted an internal fillet. This method works well on the easily cut wood but you do have to watch when doing it on metal as the percentage tool engagement can go up a lot and chatter is possible, in these cases it is better to try and draw in teh fillets with a radius say 10% more than the radius left by the tool.



A couple of mouse clicks and the thousands of lines of G-code that F360 created were on a memory stick that could be transferred to the mill.

It was now time to cut some brown stuff, however I was wary that the flanges and particularly the feet could be broken off easily if the grain was not in the right direction. So rather than cut from a solid block of timber I laminated some thin boards of Sapele together which would have a similar effect to using plywood with it's grain that runs in two directions. I glued my blank to a piece of MDF with Titebond placing a sheet of copy paper in the joint which makes it easy to separate afterwards. Sorry No video of the crankcase being machined but this is after the final cuts with the ball nose tool and I also added a 6mm hole for later alignment.



Early on Graham had suggested that the crankcase could be cast without the need for a core which would save me time having to make a core box and also keep casting costs from the foundry lower. By having the external draft angles going each way from the split line but the internal angle being constant through both haves from the open side of the crankcase this is possible. So the next thing to do was glue the outer face of one half to another MDF clamping board and then glue the two mating faces of the pattern together both again with the sheet of paper.

The inner cavity could then be roughed out with a long shank 10mm cutter and finished with a long shank 10mm ball nose cutter working it's way around the inside in a steadily lowering spiral. I also used the same cutter to form the inside profile of the end plate.



After separating the case from the clamping board and shaping the outside of the end plate the two were glued together and a fillet of filler added and sanded smooth. The actual surface of the wood needed hardly any sanding at all and came out far smoother than any of the hobby 3D printers would have done.







That's enough for tonight, flywheel pattern next.