Author Topic: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’  (Read 8991 times)

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Hi guys,

With the base and parts for the Corliss engine awaiting painting I thought I’d have some time on a couple of diesels that have been on the cards for rather too long. Though some parts of this project have already been made this won’t be a build log as such - the Throp will take precedence - but will be more on an ‘as and when’ basis. I would like to think however that I would have them finished for running at the Forncett ‘do’ in October.

Perhaps first however a little bit of background is in order….

The ED (Electronic Developments) 3.46 cc 'Hunter' has long been a 'favourite' engine. This one, still with original box, was recently passed to me as a gift from the original purchaser by my long time control line model flying friend John Leonard.



 I think I said somewhere else it hadn’t been run for forty years. John assures me it hasn’t been run since just after purchase in the mid 1950’s. Despite the dirty appearance it certainly doesn’t look as if it’s had much running though I notice it has a replacement screw at some stage. The nice thing though is it has an original needle and spray bar which can be copied.


Until this example then I had only owned an original one for a very short period when I was around 14-15 years old. I had bought it second hand and built a KeilKraft Pacer control line team racer to fit it into. Anyone remember this ad?



On it's initial outing I had had several nice flights before clipping the prop (engine was stopped) on landing. Nothing was thought about this until starting it for the next flight - that clip had broken the crankcase all around the front bearing housing where the wall section was very thin due to the bearing housing behind.  I replaced the ‘case but like so many engines over the years it disappeared, no doubt to fund purchase of another engine.

A couple of years ago John (L) asked me if I could have a look at his version, which was binding on bottom dead centre. A strip down revealed nothing more than many years of languishing castor oil crud that had gone rock hard and the con-rod was hitting this as it passed. Scraped off and cleaned with solvent it was back to running state in very quick order.

The Hunter - in it's day - was (to a young teenager) a big engine and had a reputation of being a finger grabber - a reputation well deserved I should add  ::) and this proved just the same but having never used anything but the digits to start an engine why change the habit of a lifetime :D The crackle of the exhaust in the workshop door soon had ideas of getting one for myself just for nostalgia sake but as it sat on the bench waiting for JL to pick it up I became to realise just how much I actually liked it's shape. The thought of a 5cc version didn't take long to manifest itself and a quick check of the small increase in dimensions required showed that it was significant enough to have a visual difference.

A GA was laid out and a preliminary set of drawings done ….



……  and the usual start made to hack out a crankcase from ali block. There would be a couple of challenges - particularly around the bosses where the backplate screwed to. Unfortunately at around this time my interest was distracted elsewhere (as it does  ::)) and the roughed out rectangular blocks albeit with the internal dimensions finish machined and the bronze bush installed were popped in a box and gradually forgotten.

Sometime last year I had need to turn something non modelling orientated from ali and the thought occurred to ‘just’ turn the outer front ends. All the old buzz quickly returned and again in quite a short time I had not just two crankcases but the backplates and venturi’s too. Despite a serious ‘plastic distraction’ at the time this was the catalyst for the resurgence of interest in machining and the desire to do something about those languishing Throp engine parts. Unfortunately no images of machining the crankcase parts were taken but it was machined from solid much as the ETA and Atomatic engines described previously on here.



The cases were easy enough to machine – as said, only the bosses where the backplate screws to presenting a small challenge but once done there they have sat waiting along with material cut off for the cylinders and crankshafts.



I guess some you will remember this classic old British design with a firm degree of nostalgia and hopefully, on that note, will be of interest.

I’ve been turning the cylinder heads this morning and so far the ‘cases, cylinders and crankshafts have been machined. There’s a definite whiff of ether in the air


Regards - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Vixen

  • Full Member
  • *****
  • Posts: 3075
  • Hampshire UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #1 on: February 22, 2018, 01:42:06 PM »
Hello Tug

I remember the Hunter very well. My Dad gave me his 3.5cc Hunter engine to play with as soon as I had become a teenager. I remember receiving many, many painful wraps across the knuckles before I learned the technique of starting this monster by hand. A hefty flick and follow through, don't tickle it.
I flew it in several control line planes that I had designed and built, all with the rather non original name of "HEaD Hunter" Well I thought it was a good name at the time.
It is the journey that matters, not the destination

Sometimes, it can be a long and winding road

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13860
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #2 on: February 22, 2018, 02:32:52 PM »
That's quite a nice start on both of them Ramon. The crankcases look better that the original.

Bill

Offline Admiral_dk

  • Full Member
  • *****
  • Posts: 3752
  • Søften - Denmark
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #3 on: February 22, 2018, 05:03:11 PM »
Oh Boy another fantastic build of an classic Aero Diesel from you  :whoohoo:

I do admire your work on the Corlis, but this kind of engine is really what ticks all the boxes for me  :)

Was the original also an oversquare design as yours or did you "just" increase the bore ?

Best wishes

Per

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #4 on: February 22, 2018, 11:08:19 PM »
Hi Mike - yes it certainly lives up to it's reputation - hate to think what these 5cc versions will be like as I've had some good old whacks from them. Never fear though I certainly won't be timid with it  ;D

Hi Bill - well to be fair it's looking pretty manky in the pics but I did clean that all off last night so it looks much better - just need to give it a nice run and get that smell of diesel in the workshop  :)

Per - I have scaled this up from the original at 1:1.13 on all parts throughout. Though that doesn't seem much difference I did not want to exceed 5cc. Side by side once finished there'll be a noticeable enough difference.

I'll pop some more pics up tomorrow

Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Vixen

  • Full Member
  • *****
  • Posts: 3075
  • Hampshire UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #5 on: February 22, 2018, 11:24:21 PM »
Hay Tug

When my Dad first bought the ED Hunter, we were living in one half of an old vicarage, somewhere in the wilds of Herefordshire. One day, while the engine was being 'run in' on the bench, the vicar called by to see what all the noise was about. He took quite an interest in what we were doing and even asked if he could have a go at starting the engine. Your well ahead of the story by now. The Hunter lived up to it's reputation and gave the vicar a nasty whack across his fingers. I was a young lad and had never before heard such colourful language. And him a vicar? Where did he learn it? Must have been from his sinful parishioners.

Mike
It is the journey that matters, not the destination

Sometimes, it can be a long and winding road

Online Dave Otto

  • Full Member
  • *****
  • Posts: 4693
  • Boise, Idaho USA
    • Photo Bucket
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #6 on: February 23, 2018, 12:59:08 AM »
Very nice Tug!
Everything looks great so far.


Dave

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #7 on: February 23, 2018, 08:40:14 AM »
Hi Dave - good to see you here thanks for looking in  :ThumbsUp:

Nice story Mike - quite an eye opener at that age eh?  :o

I've had some seriously good whacks over the years but nothing save the very first of any consequence. That first was done by a little AM 10 and split my forefinger open along its length, the Frog nylon 7x6 laying the flesh back as easy as any razor.

Had a good one captured for posterity by Rod (Tangler) who took it at Guilford to the amusement of the onlookers. If you take a look at this it will bring a smile to your face - <a href="https://www.youtube.com/watch?v=nhsj0N5H_0Q" target="_blank">http://www.youtube.com/watch?v=nhsj0N5H_0Q</a> - I think I may have used the same expression as your vicar  :Lol:

Despite the potential for some 'bruising' I still prefer to start by hand, in fact I have never used an electric starter, and never would on a diesel anyway but I only use wooden or nylon props though they can still produce some nasty results if careless.

Hope to put some more pics up later.

Tug


PS
Could someone tell me how to embed the You tube clip so you can watch it in the post as opposed to clicking on the link. I did manage to get it embedded but it had the link text all around it
« Last Edit: February 23, 2018, 10:28:55 AM by Ramon »
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Jasonb

  • Full Member
  • *****
  • Posts: 9466
  • Surrey, UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #8 on: February 23, 2018, 10:15:14 AM »
Ramon just copy and past the full link from your browser and paste in straight into the post, very easy to do on this forum.

So paste this without the gap https://w w w.youtube.com/watch?v=nhsj0N5H_0Q&feature=youtu.be

<a href="https://www.youtube.com/watch?v=nhsj0N5H_0Q" target="_blank">http://www.youtube.com/watch?v=nhsj0N5H_0Q</a>

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #9 on: February 23, 2018, 10:30:50 AM »
Thanks Jason - as you see 'simples' - when you know :)

Using the url bkts was the mistake  ::)

Ramon
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13860
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #10 on: February 23, 2018, 12:49:15 PM »
Nice clip Ramon....good to see that no blood was drawn either. Quick questions though from someone having no experience with these diesel engines...do they run on straight diesel or are there also additives within the fuel as can be the case with glow engines? Just curious  :thinking:

Bill

Offline tangler

  • Full Member
  • ****
  • Posts: 834
  • Christchurch, UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #11 on: February 23, 2018, 01:11:23 PM »
Bill,

Roughly equal parts kerosene, ether and castor oil with a dash of isopropyl nitrate ( to make the engine "pop"  ;)

Cheers,

Rod
« Last Edit: February 23, 2018, 01:19:41 PM by tangler »

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #12 on: February 23, 2018, 01:19:27 PM »
Hi Bill, No, no blood and it does look like a quick recovery but I assure you it did bloody hurt and for some time too :D I usually have a stout glove on but had gone to Guildford with no intention of running them. Didn't take much persuasion from Eric to change that though  :D

'Diesel' is a bit of a misnomer really. The fuel is usually a mixture of Oil (usually castor but not always), Ether and Paraffin (Kerosene)

Basic mix is 33:33:33 but that is very rarely used. Normally the paraffin is the greater portion with the oil the minimum. An additive of a nitrate to improve ignition is also usually used.

Nitromethane which is used in glow fuels in varying proportions, sometimes to very high percentages, to enhance performance is not used and as far as I am aware certainly outside of the competition arena there are no similar additives that are used in 'diesel fuel'

Regards - Tug

Ah I see Rod has beat me to it  :D
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13860
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #13 on: February 23, 2018, 01:34:29 PM »
Thanks Rod and Ramon. Glad I asked :)

Bill

Offline Tennessee Whiskey

  • Full Member
  • *****
  • Posts: 3781
  • Springfield, Tennessee. USA
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #14 on: February 23, 2018, 08:04:20 PM »
Yeah, yeah, ya chipped tis un up jas ta git me arse in teh ol’  shid eh: blasted man ( hey I’m learning  :lolb: :lolb:)
In petro chemical terms, diesel is any fuel that is used for combustion without spark. Here in the land of freedom dollars and corruption, it’s pretty much like distilling a good whiskey. Jet Fuel A is the primo, and IIRCC, believe it or not, kerosene (paraffin) is next , then come the stuff you use in your auto or tractor, and then come the stuff you keep ya bum warm wit. Sad thing about it: last time I was at our local airport, getting 100LL for my old car, Jet A wasn’t a few cents higher (minus taxes mind you) than heating fuel. Must be that supply and demand thingy  :lolb:.

Whuskey

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #15 on: February 24, 2018, 08:21:41 AM »
Dang Whiskey ya plumb twig'd ma ploy - I'll het thinka summat else noww  ;D

At one time here paraffin was used as a home heating fuel - I guess many will remember that characteristic but not unpleasant smell when you visited a home that did so. It was cheap as chips then and available everywhere - now it's as dear if not dearer than petrol and only obtainable it seems in garden centres. Reminds me - I need to get some for this year.

Near finished the ali bits for this yesterday and was out last night so will pop some pics later today

Tug

"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Craig DeShong

  • Full Member
  • ****
  • Posts: 1293
  • Raleigh, NC. USA
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #16 on: February 25, 2018, 02:31:58 AM »
Watched the video, YOW! that thing drinks fuel like crazy! You're bringing back memories.

I remember control line flying in my teen years (this would have been the early 1960's).  Here in the USA it was glow engines, and the 35 (I assume .35 Cubic inch?) was a standard.  My buddy had a FOX 35 stunt that ran like a dream.  I had a FOX 35 rocket that was a "combat" engine and it just ran flat out.

I don't remember any diesels, but there must have been some.  I'm going to have to follow this build, looks VERY interesting. :whoohoo:
Craig
The destination motivates us toward excellence, the journey entertains us, and along the way we meet so many interesting people.

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #17 on: February 25, 2018, 12:37:19 PM »
Hi Craig - nice to see a 'new face' thanks for looking in and glad it's provided a tang of nostalgia for you. I flew control line throughout my life from the age of thirteen. Though I have not flown since 2006 I still have two stunters hanging in the garage - a Nobler and a T'Bird.

Had a couple of Fox35's which were great motors for stunt - I think it has the reputation of being the longest model engine in production. It was a light and easy to run motor if a bit noisy. My preference however was for the OS Max 35 S which like the Fox 35 would run 4 stroke/two stroke if set right, right out of the box. I still have three from around twelve I was using at one time. Had a Fox 36 which was totally different kettle of fish - dreadful motor which I struggled with for some time before switching to the OS's.

Re the fuel guzzling - that was just it's second run from being built so was set very rich. None of the engines built so far have had much running - usually just once a year at a model event. Hope you enjoy the rest of the thread.



I now have all the ali parts save the con-rods done and have surprised myself how quickly the parts have been made. This is the work done so far so as you can see there is not much left to do


The crank shafts were done in my usual way of using a combination of EN24t and high tensile cap head material. This saves on En24t and has proved to more than stand up to the forces involved. The fixture is for turning the crank pins.....


.... using the faceplate.


Finished except for the taper for the prop driver. Had to get one of those small revolving centres from Arc Euro to do that. Brilliant - should have bought one years ago  ::)


The cylinders do not have a liner and as such are turned from leaded EN1a. The machining was relatively straightforward but the two bulges that are over the transfer passages required a different approach which you may find of interest .......

First up was to finish turn the bore and rough turn the basic ODs


Make a new expanding mandrel to suit the bore and machine the fins and lower flange dimensions


Then modify an old one to hold it on the mill .....




The teeth of an end mill cutter were modified on the offhand grinder.....


...... to plunge mill the transfer passages in to an exact depth


Set back on the longer mandrel the exhaust side of the case had the relief milled in


Finished example and the transfer side to do - the bulges required can be seen in the drawing. I would assume the original was machined on a copy lathe but with no access to such another means was sought.


A fixture was made to hold the cylinder via the hold down bolt holes. The two larger holes sit on the centres of the transfer bulge radii


A block was set square to the mill table with a pin set in for the fixture to rotate about


then by rotating small movements and clamping the radius was slowly formed. Once done the cylinder was moved to the second hole and the machining repeated


Back on the small mandrel to cut the scallops out - the bulges can be clearly seen here


And finally - finished ready to lap



That's it - have to go - Sues chomping at the bit - lunch with the in laws - you know the score

Hope that's of interest - I was well pleased with the way those transfer passages turned out - hope that's of use to some one

Regards - Tug

No time to preview this so any mistakes will be rectified later  ;)
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Online sco

  • Full Member
  • ****
  • Posts: 1693
  • Location: Northants UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #18 on: February 25, 2018, 02:18:01 PM »
Slick work as usual Tug!  Can you explain why you ground the end mill in order to cut the transfer ports (~10 pictures from the begining of the post)?

Simon.
Ars longa, vita brevis.

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #19 on: February 25, 2018, 10:35:42 PM »
Hi Simon - just got back home, well fed and well over watered  ;)

If you look at the drawing on the same image you can see I have tapered the transfer passage into the cylinder to assist the flow. Modifying the cutter was how I achieved a reasonable transition. As long as the actual edge does not stray far from it's designed position then the timing remains fairly close to the designed amount. The actual shape is not that important hence the freehand grinding. Usually the passages are cut into the crankcase with the porting cut into the liner to define the timing giving much larger passages but this is how the original was made. 

Bear in mind this is predominantly a model engineering exercise and not an attempt to make anything with exceptional performance - as long as it runs reasonably well I'll be more than happy - hopefully you'll 'hear' the result at Forncett ;)

Regards - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #20 on: March 02, 2018, 09:07:00 AM »
Just a small update guys,

All parts save the piston, contra piston and rotors are finished. I'll do the cast bits later with other cast bits for the Corliss.

The con-rods were made from 'Alumec 89' a very tough grade of ali.


The spinners were done in the usual fashion of a series of flats then flared using a scraper made from an old file.


The cylinder head fins were done using a home made cutter - usual silver steel, heat treated, quenched in oil - no tempering for max hardness, teeth sharpened using a worn diamond file.


A shot of the intake parts


The needles were made from mild steel rod run down to 7BA diameter. The thread was put on by die and the tail end supported in a brass centre. The taper was then put on just by filing until the end parted.


...then finished off by the usual method of supporting it on a wood support/guide to finish file and smooth - works very well


It'll be a while before the final parts are done and assembly can take place so until then I hope you've enjoyed this little diversion from the Corliss build

Regards for now - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 6133
  • Switzerland
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #21 on: March 02, 2018, 09:22:11 AM »
Very nice  :praise2: I like the setups to deal with the passages/ports  :)
Best regards

Roger

Offline Vixen

  • Full Member
  • *****
  • Posts: 3075
  • Hampshire UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #22 on: March 02, 2018, 11:03:41 AM »
Nice clean work Tug  :ThumbsUp: :ThumbsUp:

Mike
It is the journey that matters, not the destination

Sometimes, it can be a long and winding road

Offline Admiral_dk

  • Full Member
  • *****
  • Posts: 3752
  • Søften - Denmark
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #23 on: March 02, 2018, 11:45:59 AM »
Some very nice parts to your usual very high standard.

Thank you for showing the details about supporting the needle with a piece of wood - I would not have though of that, but obvious when you see it  :ThumbsUp:

It looks like you did the conrod on the lathe except for the holes.

Online Dave Otto

  • Full Member
  • *****
  • Posts: 4693
  • Boise, Idaho USA
    • Photo Bucket
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #24 on: March 03, 2018, 01:12:50 AM »
Beautiful work and great photos!
Thanks for the update Tug.

Dave

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #25 on: March 03, 2018, 10:43:48 AM »
Hi Guys - thanks for looking in and your kind comments  :ThumbsUp:

Roger - I was very pleased the way those 'bulges' machined up using that method. I had tried a similar set up on the bosses on the crankcase and found it worked well if a bit time consuming.

Per - Yes the con-rods were done on the lathe using form tools after drilling and reaming on the mill.  I didn't take any pics but I did describe the making of similar rods on the ETA thread here http://www.modelenginemaker.com/index.php/topic,1334.75.html - you'll need to scroll down to post #87



Regards for now - Tug

"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #26 on: July 29, 2018, 11:11:37 PM »
Hi Guys - With the Forncett ME Day looming on the not too distant horizon I thought I'd spend a bit of time to bring this build to an end and hopefully have something new to run this year.

As previously said virtually all parts save the pistons and rotors have been made so lapping the cylinders was the priority in order to tackle the pistons.

A previously made lap for a larger bore was skimmed to suit. Don't pay too much attention to the scratches - they were caused by trying the cylinder on before applying the lapping compound and the camera makes them look far worse that they are.



It didn't take long with the initial 320 grit to make them disappear


The liner was lapped in three stages - cleaning lap and liner between each in a jar of cellulose thinner

After the initial lapping to remove tooling marks - 320 grit carborundum paste


The interim using 600 grit


And finally a 'polish' with 1000 grit.


The pistons were turned from Meehanite the inner profile turned and milled to lighten as much as possible. Held in the usual fixture they were lapped using another 'recycled' brass lap from a previous build using 320 grit until the piston would just enter the cylinder bore at the base. A quick lap with 600 to smooth the finish and the slow process of lapping the piston to the liner by hand could begin.


No pics of that process on this build but these from doing similar on a previous engine will show the process


The piston is mounted on the Tee bar with a brass pin and a minimal amount of 1000 grit paste is applied with plenty of paraffin and oil lube. (95% to 5 %)


The piston is entered into the bore with a slow twisting motion gradually abrading both surfaces to a perfect fit. (It was described in detail on the Lapping and Honing thread)


This is a slow process and one which can't be rushed - patience is key. Despite having done it many times now there are still moments where I think it will never wear in but it always does. Once nearing the top of the stroke it's important to constantly take the piston out and clean it then go back in with just plenty of lube allowing the residue in the liner to take that final few microns off

The gudgeon (wrist) pins were made from steel dowels. Case hardened to provide a good wearing surface they have a soft core which can be drilled to accept the brass wear pads at each end. A fresh dowel requires the end cutting off to get past the hard surface for drilling...


Then the pin can then be cut adding a small amount for trimming back to finished length with a carbide tool


And that's it - with the rotors made from Tufnol it's time for a final clean of parts and assembly.



That's end of play tonight - should be able to test one tomorrow :)

It's been nice to have something to show from tha ol shid - hope that's of interest to some

Regards - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Tennessee Whiskey

  • Full Member
  • *****
  • Posts: 3781
  • Springfield, Tennessee. USA
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #27 on: July 29, 2018, 11:37:27 PM »
Well look at you go old boy  :ThumbsUp:. I can’t wait to hear these twins running. I bet I know someone else who’ll enjoy them at Forncett also  :stickpoke: ;)

Cletus

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13860
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #28 on: July 30, 2018, 12:48:44 AM »
Beautiful engines Ramon. Hope they will run as good as they look.

Bill

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #29 on: July 30, 2018, 08:34:41 AM »
Thanks guys - just to say it's been an early start, the first one has been assembled and I've just given it a first and very tentative run (It was before eight in the morning so need to be a bit considerate - I guess my neighbours will be most impressed) Whatever it's a runner but does need a bloody good clout to get it over compression  ::) and yes - no bitten fingers - yet ;D

More later - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Tennessee Whiskey

  • Full Member
  • *****
  • Posts: 3781
  • Springfield, Tennessee. USA
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #30 on: July 30, 2018, 10:29:57 AM »
Splendid news to awaken to Tug. Just tell the neighbors that the muffler fell off of your electric string trimmer  :naughty:

Whiskey

Offline Admiral_dk

  • Full Member
  • *****
  • Posts: 3752
  • Søften - Denmark
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #31 on: July 30, 2018, 11:40:02 AM »
Another pair of beautiful engines from you Ramon  :praise2: looking forward to see a video of them running  :cheers:

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #32 on: July 30, 2018, 10:53:39 PM »
Well guys it's been a good day in the ol shid though it had it's 'moments' - I bet my neighbours didn't exactly agree though  ;D


As said previously I gave the first one assembled a quick one minute run before breakfast then began assembling the second. All went well until placing the cylinder on the piston - it wasn't going to go :o Sudden realisation that despite being ultra careful to keep the cylinder and pistons matched as lapped somehow I had been ultra careless and got them switched about  :facepalm:. Keeping my fingers crossed that I hadn't ruined the first piston I swapped them around only to find the compression in both to be absolutely superb. Phew! Instant anxiety crisis rapidly diminished  :) Without a prop its very difficult to turn both of them over compression with the prop driver so am well chuffed. 

Here's the first assembled post run (with it's correct piston ::))


And the parts for the second (but before realising the pistons were wrong!)


I ran a couple of tanks through later in the morning. Starting was relatively easy once I realised that the fuel tube had come off the needle valve :facepalm2: but once that was back on securely it was not long before the right settings were found. They do need a bloody good whack though


Once the second was assembled correctly it too had a couple of tankfuls and performed as well as the first.
Here's the pair post running the next outing will be at Forncett


And here they are with the original 3.46 version as a comparison


Well that's another couple of diesels done to add to those before - hope you've enjoyed the ride

Regards - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline zeeprogrammer

  • Full Member
  • *****
  • Posts: 6811
  • West Chester, PA, USA
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #33 on: July 30, 2018, 11:07:57 PM »
Beautiful work.  :ThumbsUp:

Well guys it's been a good day in the ol shid though it had it's 'moments' -

You may have no idea how it helps to see craftsmen struggle sometimes. Sort of makes sense. If it was easy for them...there'd be no challenge or learning.

I always enjoy seeing your work.  :ThumbsUp:
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Tennessee Whiskey

  • Full Member
  • *****
  • Posts: 3781
  • Springfield, Tennessee. USA
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #34 on: July 30, 2018, 11:49:52 PM »
Just wonderful Tug. I’m chuffed for you  :cheers:

Whiskey

Online Dave Otto

  • Full Member
  • *****
  • Posts: 4693
  • Boise, Idaho USA
    • Photo Bucket
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #35 on: July 31, 2018, 01:07:06 AM »
Beautiful engines Tug! I'm sure they run as nice as they look.

Have you ever gone over your procedure on creating the beautiful finishes on your parts? I know we all have our techniques, if you are willing to share I would be interested. Or if you have covered this before a point in that direction would be nice.

Thanks,
Dave

Online Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 7862
  • Portland, Oregon, USA
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #36 on: July 31, 2018, 05:33:17 AM »
Really beautiful engines, Tug!
Thanks for sharing your work with us,
Kim

Offline Jasonb

  • Full Member
  • *****
  • Posts: 9466
  • Surrey, UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #37 on: July 31, 2018, 07:21:12 AM »
Very nice Ramon and good to see the magic glove still works resulting in a couple of runners.

can I ask why they were made with such a long crankshaft? Was it to get teh CoG back or to allow the endine to fit into a more aerodynamic cowel.

J

Offline Allen Smithee

  • Full Member
  • ****
  • Posts: 1130
  • Mordor, Middle Earth
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #38 on: July 31, 2018, 07:43:35 AM »
AIUI they were designed as marine engines and then converted to aero. The long free-end of the shaft was to give a decent gripping area for the (quite large) flywheel  needed by the marine engine.

€0.0002 supplied,

AS
Quidquid latine dictum sit altum sonatur

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #39 on: July 31, 2018, 11:08:33 AM »
Hi guys - thanks for looking in  :ThumbsUp:

Zee - we all struggle - at all levels - so don't despair when things go wrong. It's the ability to overcome the mistakes we make that makes it worth the struggle ;)

Dave - I think I may have mentioned it in passing but nothing specific as I recall. I'd be happy to pop something a bit more detailed up later as/if you think it's worth doing

Jason - I'm afraid AS is off track here. The Hunter was first introduced to the aeromodelling fraternity in 1949 as very much a new aero engine. It would appear as a marine version a year or so later. I don't recall any specific advertising feature with regard to that long prop driver but would hazard a guess that it was influenced by several Italian diesels of that time that featured long front ends and well described as you surmise by being able to be fitted well back in a cowl in order to help streamlining. As I said at the beginning my original suffered from that long shaft exerting enough leverage to break the crankcase. I don't know if that was a common occurrence but the engine was produced much later as a 'short shaft' version. It has a venerable history as an engine produced for many years, indeed it is still manufactured as a marine version (under the Hunter name) by Weston engines. Another British engine that exhibited a long shaft (but shorter prop driver length) was the Amco 3.5 PB (plain bearing) Another very powerful 3.5 it did have a reputation for breaking crankshafts ! Incidentally 'long' prop drivers were available as an accessory for many engines for just this reason of getting the engine further back.

Here's a short video for Per - turn the sound up  ;)
<a href="https://www.youtube.com/watch?v=sHLk0Su84jc" target="_blank">http://www.youtube.com/watch?v=sHLk0Su84jc</a>


Whilst finishing these parts of I've also done a bit more on the 14cc spark ignition JLE engine - 'Jefs Engine' as featured on MEM a while back.

The major parts have been finish machined - just the ancillary pieces to do


Now, just to show we really do all struggle Zee  ::)

This first liner on the left is a bin job - I miscounted the holes on the dividing device and these holes are some 36 degrees out of phase  to the second version on the right::)


Something good came out of it though as looking at it as drawn after machining I felt the exhaust was potentially rather wide for a ring to pass without catching so the second liner was done with a smaller cutter and the exhaust and inlet barred to prevent that


And - when making the 'Tufnol' rotors for the Hunters one had the blind holes drilled right through  ::) so yep ''it happens to all of us ;D

Y'all have a good time now - I'm off to tha ol shid

Ol Tug




 
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 6133
  • Switzerland
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #40 on: July 31, 2018, 05:50:12 PM »
Splendid work  :praise2:  :praise2:  :wine1: I can't see the video though  :( just a space.
Best regards

Roger

Offline Allen Smithee

  • Full Member
  • ****
  • Posts: 1130
  • Mordor, Middle Earth
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #41 on: July 31, 2018, 06:47:50 PM »
Jason - I'm afraid AS is off track here.

Hah! Hardly the first time! I tried to remember where I got that idea from. When I was a kid a schoolfriend's dad gave me an old model boat which had six channel reeds and an ED Hunter which he had converted from aero to marine. I think he said that you could see from the long front end that it was "obviously designed to fit a flywheel". When you're 12 you just accept these pronouncements as gospel!

AS
Quidquid latine dictum sit altum sonatur

Offline Admiral_dk

  • Full Member
  • *****
  • Posts: 3752
  • Søften - Denmark
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #42 on: July 31, 2018, 09:03:16 PM »
Hi Ramon

Fantastic job and I really, really like the sound and how well it runs and starts  :whoohoo:

I was going to ask you about the prop size, but you mention it being a 13"x5" in the video and that explains why it looks so substantial BIG to me  :D

Roger : 
Quote
I can't see the video though  :( just a space.
Well this is the same for me when I use my standard browser (IE11) - so I just copy paste the internet address into Chrome and it shows fine there  ;)

Best wishes

Per

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 6133
  • Switzerland
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #43 on: August 01, 2018, 08:28:43 AM »
I pasted the address into Edge and could see the video  :)

Excellent, lots of noise and lots of smells  :ThumbsUp:  :ThumbsUp:  :wine1:
Best regards

Roger

Offline Ramon Wilson

  • Full Member
  • ****
  • Posts: 1942
  • Suffolk in the UK
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #44 on: August 01, 2018, 09:08:11 AM »
Morning Guys, Thanks as usual and glad you could smell the ether Roger  :ThumbsUp:

I can't explain why some can see the video and some can't. It shows, and is accessible, in the thread on my PC well enough. I did have this problem with the video on the Corliss build so maybe it's to do with the way it's uploaded at this end. Whatever, thanks Per for a quick solution.

The 13 x 5 prop is usually only used on those initial runs - the next runs will be on a 12 x 5 and eventually it will run with a 11 x 5 which should let it really open up ;)

Ah Allen, now that's how urban myths begin  :ROFL:

Well I guess that's the end of this thread - thanks to all who have taken time to comment, as always much appreciated :ThumbsUp:

Time to move on now and tweak a bit more on the Mc'Onie before getting back on the Corliss.

Regards from the ol shid then

Ol Tug

"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Roger B

  • Global Moderator
  • Full Member
  • *****
  • Posts: 6133
  • Switzerland
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #45 on: August 01, 2018, 10:58:50 AM »
I went to the chemist yesterday to buy some ether so the smell is fresh in my nose  :)

I have attached a screen print of what  get when I right click in the space. I have found that it works better just to paste the YouTube address in the text and not use the Forum's tool.
Best regards

Roger

Offline Admiral_dk

  • Full Member
  • *****
  • Posts: 3752
  • Søften - Denmark
Re: An English Classic ? A 5cc version of the ‘ED Mk IV 3.46 Hunter’
« Reply #46 on: August 01, 2018, 11:57:00 AM »
Quote
I went to the chemist yesterday to buy some ether so the smell is fresh in my nose  :)

Careful here now as you get arrested in most Western countries for trying to buy that stuff nowadays …  :o

- Why do you ask …. - …. well the authorities believe that you are trying to manufacture drugs or terrorist boms with ether - so it is on the call the cops list when you ask for it.

It is possible legally, but you will have to get permits first, before you order it.

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal