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Jason's engine

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Ramon Wilson08/06/2011 15:42:00
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Jason I know absolutely nothing about this type of engine other than what I see.......... What a truely lovely bit of work, both in the engineeering and in the painting.
 
You suggest creating another thread - well how about telling us a bit more about it - the design, size, difficulties or not in machining/fabrication and it's performance - bet I'm not the only one who would like to hear more.
 
MEB - you are right about the latest issue - have you made a start on the radial yet
 
Regards - Ramon
JasonB08/06/2011 18:30:47
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Thanks For the compliments, I'll see what I can come up with but Wednesday night is usually workshop night
 
And no i'm not rushing off to finish that radial, too many other projects to get done first. Anyway aero engines don't do that much for me and if I did make one would probably want something a little larger around the 1" bore mark - similar size to the Hoglet that I have done about half of.
 
Stay tuned, Jason
Ramon Wilson08/06/2011 22:56:52
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Thanks Jason, no rush - when you can but I would like to know more especially as there were no castings involved.
 
The radial eh? Well I have checked - the material is about under the bench - the drawings look superb but the time???? I have two lovely vintage Italian diesels planned along with Graham Meeks four stroke so it will have to wait a while I guess
 
Regards for now - Ramon
JasonB12/06/2011 12:34:39
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Introduction

As I came towards an end of the Minnie traction engine that you see in my avatar thoughts started to turn towards what to make next. Having done several stationary steam engines I felt like a bit of a change and the hit & miss type engines interested me more than aero engines though the Nemitt was tempting as this was currently being described in ME.

Looking around it was obvious that in the UK we are not blessed with a large range of this style of engine*. Polly’s R&B had flywheels too big to fit on my lathe at the time(both 9” & 12” versions), Alyn Foundry ** had ceased trading so the RLE was out, Engineers Emporium had the little wonder but I was not keen on the alloy flywheels supplied at the time. So it looked like my choice was between Westbury’s Centaur or Wyvern, I got the back issued off e-bay and was just about to order a set of castings for the Wyvern when the latest issue of Model Engine Builder landed on the mat and low and behold the design for Dario Brisigella's zero-six
Now as some of you may have seen from my posts on this site and others I’m not too keen on the bar stock look particularly on period engines, things like socket head screws just don’t look right - give me proper studs (not studding) washers and single chamfer nuts and I’m a happy man. After a day or two looking the plans over I had started to think about the possibility of adapting the design to suit my tastes. I also found several errors on the drawing and fired off an e-mail to the editor which was quickly acknowledged and within 48hrs I had an A3 size drawing sheet in pdf format with all the issues corrected – would be nice if other mags could do something similar. MEB drawings have less errors these days as they now use someone with engineering knowledge to prepare the drawings.
 
Jason
to be continued
 
* Forrest Classics are hopefully going to be stocking more US casting kits. They have been doing the Redwing for a few months and are now selling the range from Linley Machine which includes the Dick Shelly Galloway kits which Linley have taken over the rights and patterns for.
 
** Anson Engine Museum are now starting to produce the Alyn Range, the Gardener is available and the RLE should follow soon

Edited By JasonB on 12/06/2011 12:54:33

JasonB12/06/2011 12:48:08
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How they work

Before going into the construction a few works on why these engines are called “Hit & Miss” may be in order. Unlike steam engines where the governor usually acts of a butterfly valve to control the amount of steam getting to the cylinder these engines are governed my making them miss part of the 4stroke cycle.

The governor weights activate a latch that holds the exhaust pushrod in the open position which means that there is no vacuum formed in the cylinder so no fuel/air is drawn in(miss). As the revs slow the latch will release the pushrod allowing fuel to be drawn into the combustion chamber and the sparkplug or ignitor will make the engine fire (hit) The inlet valve is usually just opened by the vacuum, there is no pushrod.
 

To be continued
John Stevenson12/06/2011 13:21:01
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Posted by JasonB on 12/06/2011 12:34:39:
 
- give me proper studs (not studding)
 
Jason

 
Jason, out of interest how do you now they are proper studs, not studding, if all you can see is one and a half threads ?
 
Just interested in the reply .
 
John S.
 
NJH12/06/2011 13:35:01
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Ah John
 
I don't wish to pre-empt Jason but, looking at the quality of his work, I suspect he might say " I just know". If so then I can sympathise with that approach!
 
Cheers
 
Norman
JasonB12/06/2011 13:35:47
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I was refering to the correct method when building a model or full size for that matter. Using studding is a quick shortcut, making proper studs with a plain central section is in my veiw the correct way to do things. Yes with the loadings our engines are likely to take you could get away with studding and who would know, well I would know whats on my engines and thats really all that matters.
 
I also find that when you use proper studs its easier to get a consistant  1 1/2 threads showing as they will all screw into the hole by the same amount, studding can keep turning when putting the nut on.
 
I'm sure you jobbing engineers will just use whats laying on the floor but I prefer my work to look likethis 
 
Likewise single chamfer machined nuts look correct on a period engine they also tend to be taller than modern mass produced forged nut and no I'm not that anal that I make all my own nuts, I either buy the correct type or if not available then I will make them.
 
J
 
Edit you read my mind Norman

 

Edited By JasonB on 12/06/2011 13:42:40

NJH12/06/2011 14:21:12
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Well Jason
 
I don't know about reading your mind but I recently made a batch of 8BA studs - and had to turn down some stock as all I had was too big. I must admit that the thought of buying a bit of studding had some attraction then! ......I note that a quantity of 10BA studs are also needed later in this project - magnifying glass out!
 
John you should try small - you would find huge benefits.
i.e. Very easy to clear up the swarf. ( and very necessary to do it often or else you lose the bit you have slaved over for hours! )
 
Cheers
 
Norman
John Stevenson12/06/2011 14:56:03
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Norman,
 
Don't like small, takes too long

If I was re-incarnated as a vulture I'd be the first one to actually kill something !

I must admit that I do use studding a lot because of the ease of it, time saved and one length can make many different lengths. I can't afford to stock studs in all different lengths and sizes plus have you costed commercial studs ?
 
Problem with running an emergency jobbing shop is that you need to have everything on stock, keeping 5 or 6 lengths of M5 up to M20 isn't as bad as keeping every size of stud.
 
I do have to make the odd ones where they are stepped or waisted and I'm pretty well geared up for this as I have blank 5C collets pre threaded for M6 to M16 so I can grip on the pre threaded part without damaging the threads.
I know I can use split nuts etc but these will get lost, at least the 5C's sit in the rack with the others.
 
John S.

 
Nicholas Farr12/06/2011 15:06:51
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Hi, well i have to agree with Jason about proper studs, V studding, especially in castings with blind holes. As Jason says, studding can carry on turning when putting the nut on and during tightening up. Normally it is usual wherever possible to have a blind hole deeper than the amount the stud will screw into it, if using studding there is a risk of the studding bottoming out, and if there is any amount of excess oil or anti-seize compound in the hole, or on the threads, there is a risk of fracture due to hydraulic pressure. If studding is used. it would be wise to drill a very small hole up the stud, and then cross drill into it above where it most likely not to be in the screwed portion of the hole, so that any such hydraulic pressure will not build up.
 
Like Jason also says, I would know.
 
Regards Nick.
John Stevenson12/06/2011 15:25:37
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Or just loctite the studding in at the correct depth, wait for the loctite to cure and assemble up as normal.
If the studs and nuts are clean there will be no forces to drive the studding deeper beyond the strength of the loctite.
 
A stud will only hydraulic if the nut is seized on the stud and cross drilling will weaken it
 
Most breakages from hydraulic incidents are caused by bolts and not studs
 
John S..
Nicholas Farr12/06/2011 17:18:07
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Posted by John Stevenson on 12/06/2011 15:25:37:
Or just loctite the studding.............
 
A stud will only hydraulic if the nut is seized on the stud and cross drilling will weaken it
 
Most breakages from hydraulic incidents are caused by bolts and not studs
 
John S..
 
Hi John, you are correct of course, but an incident I remember that happen to a colleague many years ago, and one of the studs was damaged, so he used a bit of stainless steel studding and nut on a water pump in its working enviroment and the hole had water in it, and the nut picked up on the thread (like that stuff does sometimes) and just drove the studding in and crack! So it had to go with five instead of six studs.
 
Happy Days.
 
Regards Nick.
Ramon Wilson12/06/2011 22:56:07
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Thanks for the posting Jason - been out all day so have only just read it through.
 
Whilst I can certainly see Johns point of view from his situation I'm with you and the others on making the correct studs purely on the grounds of originality. I can't envisage a hydraulic situation in these sizes however so dont quite see the potential for disaster.
I have always thought - though hasten to add have no training in such so am probably totally wrong - that the short end of a stud was taken in to the full depth of thread and torqued up. Isn't that why a stud driver is used? Otherwise wouldn't all the holes have to be such that they would allow all the studs to bottom out equally? Can the fitters amongst us say whether this is actually correct or not?
 
Thanks for taking the time to explain the principle of 'Hit and Miss' I was not aware of how this worked before and you have summed it up clearly and made it easy to understand the principle. Don't keep us waiting too long for the next instalment
 
Regards - Ramon
Martin W12/06/2011 23:32:38
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Hi
 
Slightly off topic but here is a video of a 'Hit & Miss' engine running Old Bessemer. Judging by the accents it is in the USA but still quite entertaining .
 
A video showing the exhaust valve operating/inhibiting lever working can be seen here and I think it also controls the magneto.
 
 
Cheers
 
Martin
 
PS
 
For those that have seen it apologies .

Edited By Martin W on 12/06/2011 23:46:45

Gordon W13/06/2011 10:16:43
2011 forum posts
I always thought that a stud should never be tightened onto the thread runout, this will make all the load on one or two threads, and set up a stress concentration at this same point. Of cause probably does not matter at small size and unstressed models.
jomac13/06/2011 11:59:03
113 forum posts

Hi. Common and good engineering practice with the Standard Vanguard, the 8 and the 10. was that the studs had a small saw cut from the bottom up to the plain section, This was usually only done on the engine block, not the gear box holding studs.That did 2 things firstly it cleaned the threads going in and out, secondly it prevented hydraulic lockup, now a days its not done because of cost cutting, but with a Dremel and a diamond disc its easy to do studs for small models, it also saves fiddling with small drills, which in my case I invarabley break, I can also never get them to intersect properly. Dont ask me the problems we had getting studs out of the gearbox and starter motor when broken down in the bush, 80Ks from the nearest help, it always paid to take a full tool kit, but no room for gas or oxy. Lifes a bitch sometimes, but good experience and a laugh, later.

John Holloway

PS still cannot put smilies in posts

ronnie barker13/06/2011 20:12:59
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i have seen jason's engine in the flesh and it realy is first class engineering and built to a high standard, it just shows what you can do with a keen eye.
 
i only wish more model makers would have a go at a model oil engine, they are quicker projects than a traction engine or a train and are really fun to build.
 
maybe with more kits coming onto the market here in the uk there we have afew more builds.
 
jonathan
Styx14/06/2011 08:12:11
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Hi Jason,
I looked on the Forest Classics web site for the Liney Engines, I really like the look of the Galloway engine. Is it just in the planning stage or are they selling them now?
Thanks for letting me know about the MEB mag. I have ordered 2 back issues and cannot wait to get them.
 
Steve....
JasonB14/06/2011 16:49:44
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Johnathan above bought the 1/3rd scale off teh at Harrogate a couple of weeks back, worth dropping them a line to see whats in stock. I have an original 1/6th Shelly casting set to do.
 
If you are interested in the engine then George Britnell has posted quite a few pictures of his build on HMEM, he has also done teh revised set of drawings that are being supplied with them now.
 
J

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