Paddleducks
Other Marine Models => Live steam => Topic started by: bogstandard on May 06, 2007, 08:24:12 PM
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Following on from my post about gearing for a paddle engine, I have decided to give it a go.
So I have made a quick working sketch, shown below.
One of the main criteria is to modify the engine to horizontal without compromising the ability to revert back to the original vertical engine, just by changing a few parts. A truly dual use engine.
Sorry about using paper for the sketch, but a fag packet wasn't big enough.
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Here are a few piccies of gear choice and machining.
For the choice of gears I went for the 13 tooth and the 39 tooth directly below it. Giving a reduction of exactly 3-1.
The next pic is boring the large gear using soft jaws in the lathe.
Piccy three is the different thicknesses of gears mounted on the surface grinder to bring them to exactly the same thickness.
The last one is a pair of matched gears ready to be silver soldered to their hub and shaft.
All this work took just over an hour.
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:hmmm & :hmph ....& hi PD's.... but not really sure that machining the flywheel from your TRV1 is a good idea...Mr bogstandard :coffee :?: ... so how are going to calculate this :?: :arrow:
diameter of the iron fly wheel in mm... [squared] X 0.006165 = mass/kg/m.... :lol:
then do the inverse calcs :computer :crash to MINUS the inboard BITZ +/- the mass of the output shaft as contained in the original flywheel which looks pretty big compared to the mass of your planned gear set
Your planned gear set looks :kewl ...but to be only approx 12% of the original flywheel rotational mass & on 25% of the original diameter
Oh BTW ...the ream of A4 paper hasn't left from OZ yet so will see if I can replace it with a ream of A3..... :beer
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Hi Decoy,
I thought you would pop up sooner or later, nice to hear from you again.
Typical cheapskates in Oz, promised me paper and it never arrived.
By gearing down the engine, a flywheel should not be necessary, pure brute force, but I could always drill a couple of bricks and put one either side of the output gear.
Can you explain something for me please, why do model paddleboaters always want the engine horizontal when all they have to do is turn a normal engine thru 90 deg. You can't say that it is because of space because I have built a paddler and there was just as much room in there as my normal boats, or maybe they are trying to emulate their normal position because of too much alcoholic pop.
I'm just going out now to find a dustbin lid to cover my a*** 'cos the flak will start flyin' soon.
john
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:D :D :bravo :hehe :hehe :music :nose
Hey John,
I like the cut of your jib my friend.....at last another PD ready to help repel Aussie borders.... :D :D
You've got to keep them in their place don't you agree?...... :music :hehe :hehe :nah
....Iv'e been threatened, in the past, with stealth visits from Derek (along with a certain NZ PD) but when told their BOY SCOUT compasses wouldn't work north of the equator they reverted to the purchase of a second/third hand ICBM and planned to fit this with seating so as to make the trip that way.....I didn't have the heart to tell them that there is no air in space....maybe they found out just in time... :twisted: :twisted: :D :D
Anyway John, the planned gearing of your engine looks just fine to me and is not a great deal different to the geared engine I mentioned in an earlier post.....as for why the engine should lay down....this is mainly to get the weight/mass as low in the hull as possible (just as in the real thing).
Paddlers are prone to instability in small scale sizes so every bit of weight that can be kept as close to the keel as possible is worth the effort.
The other side of the equation is...a horizontal/diagonal engine just looks so much more the part.
Ok now we can both expect some OZZIE FLAK..... :oops :sunglasses
Best regards
Sandy :towel :yeah :angel :computer :beer
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Hi Sandy,
As you said I think we are both for it now.
Anyway back to important matters, I left a 0.005" gap as you suggested and also fixed the large gear mechanically, I drilled and tapped for a 2mm cap screw and both things worked out perfectly. The small gear is in fact silver soldered to the crankshaft, great stuff Tenacity 4A, specially designed I think for stainless but it really makes everything stick together.
Here are a few more piccies, I've been busy today.
The first are the gears fixed to their new shafts, followed by a very bad picture of the bearing/support block. The next two are pictures of the main gear and motor assembly.
If all goes as expected it should be ready for running tomorrow.
John
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Hi PD's & very impressive manufacturing 'Standard John'... but :thinking still a little concerned re the :hammer loss of FLYWHEEL mass considering a 3: 1 ratio only
Oh BTW... if you are talking MOOR to that Scott from Lockie......held something... please pass on my best wishes to Kate & himself... but let him know the ICBM ran out of 'Department of Aeronautical Registration'... bald tyres, steeering link geometric problems etc so I traded it in on a little newer STELPH something that will float on hot air & between you two there is plenty of that.... :hehe :music .... :angel
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Hi Derek,
Still concerned over this flywheel thing aren't you, when it is finished I will try to prove to you that the flywheel isn't really needed.
What you don't realise is that you think this little engine is only a few inches long, in fact it is nearly two feet and more than enough to power one of these model paddlers.
With reference to Sandy, I think he was trying to get me to bite a bit more. I don't need to threaten from a distance, I think the offspring of my tribe actually own Melbourne by now (not from riff raff convict stock but genuine settlers), so expect a knock on the door late at night.
Anyway, back to the business in hand, Sandy gave me some very good tips and it has turned out there is negligible friction in this gear train, which really surprised me. Making the base plate today and also a new lubricator because the one for the upright engine will not fit when it is horizontal, they are only bolt on goodies so it doesn't stop me reverting back.
If anyone from the UK is reading this and needs a little bit of machining doing (not "can you just build me this twelve cylinder radial engine"), say a bush fitting into a pulley, modifying a part, MAKING A FLYWHEEL or something similar, as long it doesn't cost me anything (you pay all postage and materials) I will do it for free, just to keep me occupied while I'm off work. But bear in mind, nowadays 2" diameter brass bar is over £5 an INCH, and if you are fairly local and willing to come round I will most probably do it while U wait.
John
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Sorry PD's... John.....not concerned .....but if our steam GOD [Mr Watt or whom ever] :respect2 made a fly wheel on the engine then who are we :sob to remove it :?:
With reference to Sandy... well he is aware that I am FIRST class convict stock ....in chains to OZ
Your [bogstandard] RELOS being gentile full fare paying passengers will not be accepted at my door any time of the day or night
Anyway, back to the business in hand, Sandy - have spoken with the same [once] via 20,000 miles away & even as Scott he is 11 outa 10 & :no1
With respect to your surface grinding table... is this an M&W 6" X 12" model 2353 :?: ... if so did you use a subelemental ground transition plate between table & the goods ???????????///////////////////////// & are those shafts 3 or 4 mm stainless X 9 flanged & ZZ S/S bearings?............. :beer
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Hi Derek,
Please don't try to baffle me with technical jargon, you know that I am a fag packet man and if it works, it works, if it looks right, it is right and if it don't work, fix it so it does. Doing it this way I get things that work, and work well.
The mag chuck on my surface grinder is I think 6" x 4", made in god knows where, but gets the job done and cost about £60. When I obtained my grinder a few years back it came with a 12" mag chuck on it, but because the longtitudinal throw of the table is only 8" I couldn't resurface the chuck, so it was sold and the proceeds bought this chuck and a new vice for the miller.
The bearings in the engine before I modded it were 6x13 flanged ZZ S/S.
All four bearings now are 5x13 flanged ZZ S/S. The reason for changing the bearing was that the small gear needed to be bored out and because it was such a small size I didn't want to weaken it any more than necessary, so I bored it to 5mm.
I hope this answers your questions OK.
AND WHATS WRONG WITH FULL FARE PAYING PASSENGERS, you should be grateful that our kind did you a favour and got you transported to where you are now, no gratitude you lot. :respect
John
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:D :D :twisted: :nose :nah
Hi All,
Good on yer John...sock it to him.....
I am pleased the gearing has worked out Ok for you, amazing what a few thou can achieve, in the right place.....anyway John it certainly looks good....most excellent work.....20/10 sir.
I agree you don't need a flywheel, especially since your engine is double acting with cranks at 90 degrees to each other and, I might add, a semi balanced crankshaft.
My version (shown on the loco in earlier post) did not have one, and it runs as smooth as a baby's botty.
Never mind that Mr Watt or that Stephenson guy....the main reason for a flywheel is for getting over dead spots (typical on single or twin cylinder, single acting engines) and to some degree on a single cylinder slide valved double acting engine....all of these have dead spots to a greater or lesser extent which, when running very slowly, can make for a jerky run at best...on single acting engines without a flywheel the result could mean a stop situation.
To a much lesser degree, the same applies to 2 cylinder double acting slide valve engines especially ( even more so with FROG units...these run best on Garlic Fumes :hehe :music ) when you consider that a lot have steam cut-off at about 75% - 80% stroke.....then these to can suffer from jerky slow running without the additional flywheel inertia.
2 cylinder double acting oscillators don't suffer from this, since their steam cut-off is more or less 100%, (or should be) and therefore powered all the way up and down the bores, however, a small flywheel can be beneficial in smoothing out any imbalance in thrust which is generally present at either top or bottom dead centres on either cylinder whilst the other is at mid stroke. The down side is, of course, they use a lot more steam than slide valved engines.
Derek....your latest stealth vehicle will not work either.....what you perceive as hot air is in fact a cloud of COLD plasma...contained within a magnetic bubble, and is the product of the COLD FUSION reactors John and I use as power sources for our workshops......Now COLD Plasma is also akin to anti-matter and the magnetic field will attract any stealth flying objects (made of normal matter) and drag them in to the cloud....MATTER AND ANTI-MATTER DON'T MIX....He he :hehe :hehe :clap ...so it's back to the drawing board for you again.
Keep up the pressure John :respect :respect2 ....he's cracking..... :sunglasses :shoot and I like the visit from your relatives idea.
Best Regards to all.
Sandy. :vacat :angel :computer :beer
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Hi Sandy,
Thanks for the compliments, we try to do our best. I don't know if you knew but I had an accident at work and it has left me with a dodgy right arm, so most of my work is done one handed. It took nearly two hours last week to change the gears on my lathe for screwcutting, bits of wood stuck here and there holding the bolts while I put the nuts on, but at least the dog learned a few new words.
I knew about the reason for flywheels but I didn't want to get into an argument with him. In fact my trade from years ago is an aircraft technician so I could baffle him with a few words about theory of flight, but that would be lowering myself to his level.
Back to the main subject, couldn't do much today, medical appointments but still got these done.
The first couple of pics are the engine with a new baseplate, not totally happy with it because the metal tore as I was machining it, you must know what aluminium is like, I hate machining the stuff, I'd run out of paraffin as lubricant and had to use WD40 instead, but it burns off too quickly. Plus also the collars to hold the main shaft central.
The third piccy show the only things I have had to change on the engine, a couple of pipes and a new lubricator, still to be silver soldered up.
John
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Finished at last,
Took a little bit longer than anticipated but all criteria have been met.
The engine has been run on 30psi of air, throttled down to very slow tickover and couldn't stop the shaft turning, total brute force, if you got weed round your paddles, goodbye paddles. A guestimate of 20 to 30 mins should see the motor returned to vertical operation (if ever it was needed), a true dual purpose engine. :clap
Derek, from your posting earlier today does that mean you have admitted defeat? I know how much you like flywheels so I have posted a piccy at the bottom just for you.
I personally don't think the horizontal engine looks quite as elegant as the vertical one, but as they say, beauty is in the eye of the beholder.
Next project, was going to do a few piston valve engines of the same bore and stroke, but who knows, any suggestions?
I hope this article has given others the inspiration to have a go at doing something different.
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:D :D :no1
Hi PD's,
Don't know about the rest of you, but I think John deserves our esteemed admiration for this superb effort.
John, I knew you had some sort of difficulty with an arm, from one of your earlier post, however, I did not realise this was so severe....I can only hope that this is not a permanent thing...I say this, since you mentioned being off work, presumably whilst things mend.
I for one am amazed at your standard of work, given the circumstances, and can only guess at the results when you are fully fit....I raise my marks to 50/10....and why not teach the dog to change the gears for you?.
BTW...I to spent a good number of years in the aerospace industry, however, in my case this was more on the Avionics side, rather than airframes....so between us we could really baffle our Derek....
As for aluminium....yes I find it a pain also....it takes so very little to get a pick up on the tool with the resultant tearing...even with the correct lubricant (paraffin or soluble oil) I find that some ALI cuts well and behaves whilst another piece cut from the same stock just decides it ain't going to play ball, despite really sharp tools, correct cutting speed etc etc.....HORRID STUFF....I avoid it as much as possible.
I don't know if you are aware, so just a tip, if you are using Silicone or Viton o-rings anywhere on your engines...be sure to keep WD40 well away from them...it will make them swell up and hence destroy them in a very short time.
As for our Derek...no I don't think he is sulking....more than likely he's trying to find a suitable comeback.......anyway, we mustn't be to hard on him...he's a good sort really...not his fault he is from dodgy stock... :hehe :hehe ....In his defense I will say, he has a good excuse..since the colonial libraries in OZ (especially in Wollongong, where even e-mail is delivered by kangaroo express) are of the firm opinion that a latest edition book on steam consists of: -
'A theory of steam' written and published in 1765....this is a modern book to these guys......I'm not sure how he heard about Watt and Stephenson.
Finally, John, are we going to see your engine in a paddler model?
Best Regards to all.
Sandy. :vacat :sunglasses
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Hi Sandy,
Many thanks for the compliment, I wasn't after any sympathy, just showing that even with a slight disability people can get things done, it might take a little bit longer but you shouldn't give up. The 'off work' thing was saying that I might be able to get back into employment, but after three years at home, doesn't look too promising. My arm is not totally useless, I can pivot it at the elbow and use my thumb and forefinger most of the time, but not with much force, just waiting for a second op, but that cannot be done until my diabetes is better under control (terrible the things you catch as you get older). They say that with another op it 'might' improve.
Anyway, that is the last time it shall be mentioned, were here to make things, not talk about my problems. There are people a lot worse off than me, and a lot that aren't but won't get off their a****.
By the way, the dog only comes into the workshop when it wants something, usually after a few hours of chewing a bone and can't get any more out of it, he brings it to me to break in the vice for him, keeps him going for another couple of hours. Cunning little devils these animals, even he knows that having a workshop is a good thing, just wondering what the cat will want, but he usually keeps his distance, when something goes wrong, its him that does somersaults and backflips down the garden with a size 10 up his backside.
I know about the problems with WD40 and seals, I think one of its constituents is like white spirit and I think that this might be the trouble.
Just talking about viton o-rings, I have a friend that used to work for RAPRA (Rubber and Plastic Research Assoc., now defunct) he said that when DuPont (I think that's who developed it) first brought viton onto the market one of the properties was that it can withstand fairly high temperatures, but over a certain temperature, like a naked flame, the polymer breaks down and produces an acid that burns straight thru body tissue, supposedly firefighters had a bit of trouble when attending car crashes and resulting fires, because these seals were used a lot around the engines. So the moral is, don't try to see if you can set alight to a viton o-ring. Just another bit of useless information stored in the grey matter, god knows what else is in there.
The engine will sit on the shelf with the others I have made, it was just an exercise I fancied carrying out, to keep me occupied and almost mentally stable. It won't have a boat to go in, my building days are over, I just can't make and sail them any more. I just keep dropping things on the floor, with metal it just bounces, and eventually you find the bit again with no damage, but with model boats when you drop something and can't find it, it is that sickening crunch underfoot that tells you that the minute bit you have just spent hours making now needs to be remade. My workshop is bulging at the seams with model boats, finished, under restoration and part built, with all the related items that go with them after 40 years building. My loft has boat kits in there from 20 odd years ago, ready for when I retired, but sadly I will not build them. I have a Dusseldorf fire boat sitting on the bench, modified to get it to near true scale, 90% complete, with all special electronics and special motors, I'm talking about £900 worth at least, last worked on nearly a year ago. One day I will get round to cataloguing it all and stick it on ebay. One thing that might interest PD's is I have dozens of lovely geared motors of all sizes, all designed to run from 24volts, but when run on 12v. they turn at just the right sort of speeds and they pull next to nothing (usually around 100ma.), you can sail for a couple of outings on one charge. None of your cheap plastic gears here, v-e-e-e-e-ry high quality. If someone can arrange pickup and distribution they can have them for a couple of quid apiece, but NOT to make large profits for themselves, these should be for everyone. I just cannot be bothered to send out a couple here and a couple there, including motors without gearboxes there could be hundreds of 'em.
Goodness me, I think I must have caught that bug from down under, it has made me ramble on about garbage for ages.
I've got to get another project started, it gets me out of the house and into the workshop away from the ball and chain, mind you she's great at climbing into skips at the local scrapyard getting me the odd bit of metal, but not much good at carrying heavy loads, she could only manage 12 sash weights a couple of weeks ago, but I suppose it will keep me in cast iron for a bit.
That damned ramblings back again, this is worse than I thought.
John
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Hi PD's - :towel - as John mentions.........just talking about viton o-rings,
Yes VITON elastomer was developed Du Pont [which was a Company started in New York by Canadian brothers] [from memory]
VITON when exposed to temperatures @ 315 degrees C or + decomposes & forms HF [hydrofluric acid] :offtopic & all MSDS warn about this.... however it is a little overstated as the HF must still be in a liquid state to cause the :hammer of skin which has required amputation to :boom stop the decay of flesh
VITON sealing is used in many hydraulic cylinders exposed to high temperatures @ the Port Kembla steel works, and in my role as the Contract facilitator for all cylinder repairs allows me to see many burnt degraded VITON seal elements
But we ozies are tough - we don't get bugs :hehe .. we have Vegemite, garlic + red wine
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Hi PD's......yes just me again :music .....& John noted
Derek, from your posting earlier today does that mean you have admitted defeat? I know how much you like flywheels
Well firstly John NO...ausies never admit defeat... we are not taught that word at school as we were spared your defeaters like the Vikings, the Romans, the Monguls... just to name a few :nah
Having said that we are never embarrased to admit we may not know the answer to a question... & my question naturally is WHY do JMC & ANTON & a few other British manufacturers + one German + on YANK install the fly wheels on multi cylinder 90 degrees opposed [slide valve self starting engines] if they are not necessary :?:
Oh PS.... not grovelling but must agree ... :kewl of your top quality work
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Hi Derek,
Thanks for the compliment about the workmanship, as I have said before, do the best you can.
Thanks for the full info on viton, but it does go to show that unless you are willing to chase things up you would never know about it. People buy things from engineering suppliers not knowing the full story, and I know that it is very unlikely that people will have an accident, but the chance is always there. But I don't think that they will stick a warning label on every little o-ring sold.
I used to be a maintenance engineer in an electronics company many years ago, just as C.O.S.H.H. was being introduced, it was my job to gather and collate all the information about products being used in the production areas, and the properties of some of the items defied belief, one that instantly springs to mind was a potting agent that was a definite carcinogen and a suspect mutagen, being used openly and no safety gear by young women.
Cyano, epoxy resins and glues, silver solder to name just a few are all in general use by model makers and all have their own horror stories, but how many take any precautions when using them, I openly admit to sometimes not using them, 'Oh its just a quickie' and it won't do me any harm, but a lot of items do have a cumulative effect, and it is when you get to the stage that there is enough in your body, things start to happen.
So be warned, if it says to use gloves, use them, if it says don't breathe in the fumes, if your an ozzie, don't breathe, the rest of us can use face masks or extractors.
Your quote - But we ozies are tough - we don't get bugs .. we have Vegemite, garlic + red wine - No wonder you won't admit defeat, its not that you're tough, no one will come near you eating and drinking muck like that.
John
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:D :D :computer
Hi Pd's,
Derek asks: -
Having said that we are never embarrased to admit we may not know the answer to a question... & my question naturally is WHY do JMC & ANTON & a few other British manufacturers + one German + on YANK install the fly wheels on multi cylinder 90 degrees opposed [slide valve self starting engines] if they are not necessary
An Honest question, which deserves an equally Honest answer........the reason is it is the most cost effective way for model engine manufacturers to DAMPEN (not eliminate) the shake and vibration created by the engine whilst it is running.
The reason for this shake and vibration is, unfortunately, not an easy subject to go into, at least not in any detail, on a forum such as this.....most of you would have gone to sleep before the first page was finished... :hehe :hehe since it is quite a technical marathon.
Briefly though, whilst it is possible to STATICALLY balance a 2 cylinder engine, having cranks at 90 degrees, it is not possible to DYNAMICALLY balance the same. The result is both sideways and for and aft shake.
A heavy flywheel serves to dampen these forces to more acceptable levels.
Full size marine engines are not fitted with flywheels, but that is not to say they do not have some means of achieving the same.....for paddle engines in particular, use was made of the rotating mass provided by the heavy paddlewheels...( hence my statement that John did not need a flywheel)...whilst on screw driven vessels, the necessary rotating mass was often provided by the heavy thrust blocks employed at the propshaft connection, or by incorporating some additional weights elswhere on the moving parts of the engines, also such vessels usually had a very heavy rotating mass in the propshaft/propeller combination, however, the prop was often the source of yet more vibration.....TRICKY !!!!
Large steam engine manufacturers often employed a balancing technique developed by 'Yarrow, Schlick and Tweedy' but this involved some pretty heavy theoretical calculations and specialised manufacturing techniques which, whilst fine for such companies, would not be even vagualy feassible for model engine builders....UNLESS THEY CHARGED 7 figures for their products....
Ok Derek, I hope that helps explain thing a little....for anyone who may be interested...the above mentioned balancing technique is explained in some detail in : -
J.W.M. Sothern, "Verbal" Notes and Sketches for Marine Engineer Officers, 18th Edition, James Munro & Co. Ltd., Glasgow, [no copyright date given], pages A6-A7.
But be warned.....it is quite heavy going. :twisted: :twisted:
I can/will expand a bit more on this subject if anyone thinks it of benefit.
Best Regards to all.
Sandy. :vacat :computer :coffee
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Hi PD's & I'll respect your comments here Sandy
J.W.M. Sothern, "Verbal" Notes and Sketches for Marine Engineer Officers, but be warned.....it is quite heavy going.
Sounds like a nice :no1 book to read on a Sunday morning :great warm toast with Vegimite + garlic +Twingings English Breakfast tea :hehe followed by a few glasses/jugs of red ned :nah.....'read a few pages' then followed by luncheon of medium char grilled kangaroo TAIL W roasted garlic W smoked witchidegrub sauce W a few :beer to wash it all down :music - the land of OZ :bow where we have a seven day :vacat every week
Oh BTW, in European cooking many use Paprika....that red powder....in OZ cooking we use our own variation on that theme of red powder it's called IRON ORE... helps to keep us tough :yeah ...however to balance this & stop us rusting we need 1/4 of a cup per day of fish oil :sorry PD's...I know this is not a cooking forum but couldn' resist