Horizontal twin paddler engine

[Eddy Matthews]

Absolutely no disrespect intended here, but I would personally like to see the engine in the original post, as I feel it's a lot more realistic (visually) for a paddler. An oscillator with those cylinders wobbling back and forth just doesn't do it for me

So how about a compromise? Make the original engine as per the drawings, but reduce it to approx 2/3 size?

Regards
Eddy

[Harold H. Duncan]

OK PD's.... hehe...considering OZ is the first location in the world each day to see the new sun each morning...I am the first to respond to bogstandard...& by that time it is   Coffee...so good morning John.......


See folks, them ozzies think NZ is just another state of theirs, ist a well known secret that NZ is always the first country in the world in the to see the sun rise on a new day. We aint always the first up out of bed to see it but, so will give you that one Derek

Cant wait to see your new engine John

cheers
HarryD (kiwi)

[bogstandard]

Good evening Harry, I am a raging insomniac, so time usually means nothing. Just awake and not awake.

So how about a compromise? Make the original engine as per the drawings, but reduce it to approx 2/3 size?

It doesn't work like that Eddy, to reduce in size is dead easy to do mathematically, physically it is a lot more difficult.

Bandit has done a few calcs for me.

Imagine the crank, 5mm at the moment, roughly 3.5mm after conversion. The crank would most probably twist like a rubber band at that size, so that would really have to stay at 5mm, so imagine having to go thru the whole engine and look at every part to see if it would take the forces acting upon it. Pipework can only be reduced so far, so basically you have a larger scale pipe going into a smaller scale hole. These are just a couple of examples, I am sure there will be a lot more examples.
That is why this type of engine needs to be as large as it is.

A complete redesign would be called for, to reduce the stroke to a much shorter level, then the engine would start to become a 'square' engine, and usually this means it will need to run a lot faster to produce the power, and so would need to have a larger gearing stepdown, and it goes on and on.

You only have to look at the Anton offering

http://fabrice.bretagne.club.fr/Moteur%20Quartz%20Horizontal.htm

Something this size would be dead easy to make, but longevity of the engine has been sacrificed to get it to such a compact size, also note the diameter of the crank in relation to the rest of the engine, this proves my point noted above. Note also, no steam packings, no support of the crosshead. To me that doesn't shout longevity, just bad friction wear points.

So basically, to have a scale looking, very robust engine, that needs to be physically larger to get the operating system in, or a compact size that looks awful, but does a good job.

John

[Eddy Matthews]

Thanks for the detailed reply John... Not being an engineer, I hadn't even thought about some of the technicalities. It was just a suggestion for those that didn't want such a large engine.... But if the problems make it a none starter so be it.

Regards
Eddy

[kno3]

Hello all! Very small engines can't be done? What do you think about this horizontal engine then? Perfect for a pocket-paddlewheeler. 
It was made by a German named Georg W. Held.

[bogstandard]

Hi Kno3,

I was not saying that small engines can't be built, here is one I knocked up in a day

http://uk.youtube.com/watch?v=76_TtDfYPCo

What I was trying to explain, that to get to a useable size what these lads require, a slide valve or piston valve type will be physically larger than an oscillator of comparative stroke and bore, because of the valve control gear. In fact there is basically no difference in steam requirement for a piston valve engine or oscillator, just the piston valve looks nicer, but you will lose a bit of power because of driving the valve gear. Slide valves are slightly different in that you can adjust the steam timing as well, but have the disadvantage of using an extra channel just for speed control.

I will see what I can come up with regards to getting the slide valve a bit smaller.

John

[kiwimodeller]

John, I would be a starter for the engine at original size, it would fit fine in my 2m long paddler and I am sure the present boiler would be more than adequate. It would replace the present single cylinder to A H Rayman design which would elimate the usual single cylinder starting and reversing problems and also get the weight down lower which would help with the amount of lean in turns. The single could then get coupled up to a flash boiler which Rayman also offered as an optional design and could go in a steam hydro which is another dream for "one day when" or perhaps a hydroplane paddler if Ernies works.
Derek, just because the sun shines out of your nether regions does not mean that it is the first place to see the sun each day! That is why droves of people did not come to Aus to see in the start of the new millenium in case you were wondering. Cheers, Ian.

[bogstandard]

To try to sort out the problem, I have come up with a few ideas to get the size down a fair amount, still end up with a powerful engine, and have a good complicated looker, and reliable, just by moving the control gear onto the top of the cylinder and a scotch yoke action for the piston valve being driven by the big end. I will see what it looks like when I get it onto paper and do a few calculations. Length is a problem because just for a basic calculation you need about 3.5 times the stroke to fit everything in, so 15mm stroke, the engine will be about 52mm long.

Just going out now to smoke a few thousand fags to get all the packets I'll need.

John

[Dave_Sohlstrom]

John and all

I have been watching this thread with some interest and questions.

At 15mm stroke I am having a hard time understanding why this is being called a large engine.
I am working on a model of the steam stern wheel tug Portland in 3/8" to the foot scale and the engine will be .813" bore and 3.375" stroke and I think of it as small.

What am I missing here.

Dave

[Eddy Matthews]

I've added a Poll to the topic, which should help to clarify which engine members would prefer to see John build...

Eddy

[derekwarner_decoy]

Hi PD's....& yes Dave I fully acknowledge your point that the MVhTC14x18 00..as built would fit into a shoe box....so certainly is not big...& you could fit 10 into the boot of a Mini Minor...so that reinforces the fact that they are not BIG

My simple comments were intended that this engine has a much larger footprint ....than most of the offerings on the commercial market

To my knowledge, the only similar sized commercially available engine is that Y2D2 horizontal twin from SAITO...regards Derek

[kiwimodeller]

Eddie, having voted in your poll it occurred to me afterwards that you did not include what I am sure would be the most popular option, namely "all of the above" just to keep John occupied for a few days. Cheers, Ian.

[Eddy Matthews]

Now now Ian.... We don't want to overload John with work so he cuts corners do we? 

I was tempted to put in a "proper" diagonal engine as well, but I thought John might have hit me!! 

Regards
Eddy

[bogstandard]

Seeing it is being put to the vote, I will stop any further single brain cell power being wasted, until the results are known.
I will knuckle down when the finals are in.

Hope to have the new lathe here wed or thurs, so that is going to take up a lot of my time getting it all set and levelled. Maybe a week or so on that.

Is anyone going to the Midlands Engineering Exhibition this weekend?

http://www.meridienneexhibitions.co.uk/our-events-detail.php?id=0000000007

If the doc can sort me out a set of crutches, and the weather is fine, I will be trying to get there on my mo'sickle on Saturday. Too far for me to drive the car.

John

[Dave_Sohlstrom]

Hi again All

I think I now see where my confusion is. When you say paddle wheel you are talking about one that is chain or gear driven of the crank shaft of the engine. When I think Paddle wheel I see one that is direct coupled to the engine via pitman arm. As in the picture below. From center of shaft to center of crank pin is 4.5 feet in this picture and will be 1 11/16 inch on my model.

I did down load the plans from post one and it is a nice looking small engine 

Dave