Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Steam => Topic started by: MOG8 on April 22, 2013, 03:58:43 pm
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I am pleased to share with you the first few images of the new Steam Engine "ENGLAND" a three-cylinder engine designed by Martin Baylis, designed from a rib of the twin cylinder "England".
3-cylinder Bore x Stroke: mm. 9 x 12, with a displacement of 4.58 cc.
Change of direction RC, by Maudslay reversing gear.
RC throttle control.
This engine is not yet officially on sale, and the tests which are carried on are very encouraging,.
It is very light, very powerful, and very fast: it can reach 3,000 rpm without problems at 3 bar.
It is technically very advanced:
Crankshaft, eccentrics and big ends are supported by needle bearings.
Cylinder block, valve box and motor base are made of hard anodized aluminum.
Smooth piston without o-rings. The sealing between the piston and cylinder occurs when the motor is thermally ready to run through the expansion of the cylinder block. In this phase of preheating, the condensed steam can thus escape through the exhaust pipe.
Its very detailed and refined aesthetics have nothing to do with the English sand castings to which we are very familiar or with the squarish shapes of the new CNC engines.
You will find the outlines of the engine here:
http://www.model-steam-engines.co.uk/page5.html
The price?
Keep dreaming!
(http://farm9.staticflickr.com/8265/8662474639_8b1465221c.jpg) (http://www.flickr.com/photos/35088074@N03/8662474639/)
Exhaust End (http://www.flickr.com/photos/35088074@N03/8662474639/) by STEAMPROPULSION (http://www.flickr.com/people/35088074@N03/), on Flickr
(http://farm9.staticflickr.com/8251/8663553366_84112a690f.jpg) (http://www.flickr.com/photos/35088074@N03/8663553366/)
Cladding Oblique (http://www.flickr.com/photos/35088074@N03/8663553366/) by STEAMPROPULSION (http://www.flickr.com/people/35088074@N03/), on Flickr
(http://farm9.staticflickr.com/8240/8662474611_66350e994a.jpg) (http://www.flickr.com/photos/35088074@N03/8662474611/)
Cladding side (http://www.flickr.com/photos/35088074@N03/8662474611/) by STEAMPROPULSION (http://www.flickr.com/people/35088074@N03/), on Flickr
(http://farm9.staticflickr.com/8265/8662474673_aa1386ea92.jpg) (http://www.flickr.com/photos/35088074@N03/8662474673/)
Exhaust Oblique (http://www.flickr.com/photos/35088074@N03/8662474673/) by STEAMPROPULSION (http://www.flickr.com/people/35088074@N03/), on Flickr
(http://farm9.staticflickr.com/8241/8662474703_397927ffeb.jpg) (http://www.flickr.com/photos/35088074@N03/8662474703/)
From above (http://www.flickr.com/photos/35088074@N03/8662474703/) by STEAMPROPULSION (http://www.flickr.com/people/35088074@N03/), on Flickr
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(http://farm9.staticflickr.com/8245/8662474729_5eafaa0c7d.jpg) (http://www.flickr.com/photos/35088074@N03/8662474729/)
Inlet End (http://www.flickr.com/photos/35088074@N03/8662474729/) by STEAMPROPULSION (http://www.flickr.com/people/35088074@N03/), on Flickr
(http://farm9.staticflickr.com/8249/8662474777_599dd2da2c.jpg) (http://www.flickr.com/photos/35088074@N03/8662474777/)
Steam Chest Oblique (http://www.flickr.com/photos/35088074@N03/8662474777/) by STEAMPROPULSION (http://www.flickr.com/people/35088074@N03/), on Flickr
(http://farm9.staticflickr.com/8242/8662447653_1baa3b91cf.jpg) (http://www.flickr.com/photos/35088074@N03/8662447653/)
Steam chest side (http://www.flickr.com/photos/35088074@N03/8662447653/) by STEAMPROPULSION (http://www.flickr.com/people/35088074@N03/), on Flickr
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What a well engineered piece. :-)) :-)) Love to see it running. 8) 8) 8)
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Looks lovely, know naff all about steam but always love the engineering of small engines. Bet she has a price tag to go with the splendor.
Si:)
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Looks lovely, know naff all about steam but always love the engineering of small engines. Bet she has a price tag to go with the splendor.
Si:)
Eddie,
Bank loans spring to mind !!!!!
George.
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Shame Iv spent my pocket money
I wish
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I know that they're amazing pieces of miniture engineering but, are they really that expensive? What are we talking about? £100, £200, £300...more.
Si:)
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I know that they're amazing pieces of miniture engineering but, are they really that expensive? What are we talking about? £100, £200, £300...more.
Si:)
Eddie ,
You wish !!!
Not much change from 1k maybe 2k
George.
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WHAT?! I'll stick to electric boats then. So, you need engine, boiler, pipework etc...so you have just spent a small fortune before you even think about the boat you're putting it into. A real passion to spend that sort of money.
Si:)
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Steam ain't cheap if you are buying it in.
Colin
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Sounds like it Colin, beautiful to see and hear but, sadly way beyond my cash flow.
Si:)
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Sounds like it Colin, beautiful to see and hear but, sadly way beyond my cash flow.
Si:)
It doesn't have to be... take a look at mad mikes inspirational thread
http://www.modelboatmayhem.co.uk/forum/index.php/topic,39774.0.html (http://www.modelboatmayhem.co.uk/forum/index.php/topic,39774.0.html)
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Beautiful engine, one thing I can't help but wonder- why the centre height of the crankshaft is so high? There is no room at all for mounting the engine straight onto engine beds, or on a common tray with the boiler, as the engine would have to be mounted at quite steep angle to make alignment with the propshaft viable.
The cylinder casting is a work of art, looks absolutely perfect!
Greg
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Don't need to worry about blow holes and inclusions when the big (and small) bits are cleaved from "Billet". As George mentioned on one of their previous efforts, Displacement lubricator can't be very effective. Strange choice of material despite tough skin.
Regards Ian.
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Ian,
It's the old adage " if it looks too good to be true it probably ain't " apart from the peculiar position of the lubricator it's never a good thing to make engines without a crosshead on the Con-rods even though the piston rods have long guides and to have needle bearings on the main shaft it will have to be a shaft that's pinned together with grub screws which can create long term problems.
Not sure whether it's supposed to be a triple expansion engine or is just a pretend one with the different size cylinder covers and the Maudsley reverse gear isn't a new thing, Cheddar used it on one of their engines.
It never ceases to amaze me that engine makers advertise engines that will do 3,000 rpm on 3 bar, yes it will do that , on the bench , but not in the water driving a boat and who in their right mind would want 3000 rpm in say a big tug, it will take a big boiler with a big fire to maintain those sort of revs.
Apart from these observations it's a well made engine but I fear that it will be way out of reach of most modelers price wise unless being CNC machined they can churn out hundreds of parts to keep the cost down.
George.
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Evening George..........I am a little lost with the following...
" it's never a good thing to make engines without a crosshead on the Con-rods and to have needle bearings on the main shaft it will have to be a shaft that's pinned together with grub screws which can create long term problems"
I am unsure of the issue in the relationship between pinning a crank with HPGS & having assumed Torrington style sealed needle roller bearings......& assume these to be stainless steel caged & ZZ fully sealed
We can all learn from experience :-)) .........regards Derek
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Beautiful engine, one thing I can't help but wonder- why the centre height of the crankshaft is so high? There is no room at all for mounting the engine straight onto engine beds, or on a common tray with the boiler, as the engine would have to be mounted at quite steep angle to make alignment with the propshaft viable.
The cylinder casting is a work of art, looks absolutely perfect!
Greg
The centre-line of the crankshaft of this engine is 14 mm high from the base. That if the TVRIA is 12 mm.
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Evening George..........I am a little lost with the following...
" it's never a good thing to make engines without a crosshead on the Con-rods and to have needle bearings on the main shaft it will have to be a shaft that's pinned together with grub screws which can create long term problems"
I am unsure of the issue in the relationship between pinning a crank with HPGS & having assumed Torrington style sealed needle roller bearings......& assume these to be stainless steel caged & ZZ fully sealed
We can all learn from experience :-)) .........regards Derek
Hi Derek,
Lets see if I can enlighten you to re-find your way.
If you look at any of the Stuart engines and the one made in OZ you will notice that the con-rods are connected to a cross head that slides up and down in the cross head guide, this takes out the strain of the angular thrust on the piston rod as the piston drives up and down and greatly reduces piston and piston rod wear.
To have needle bearings on the main shaft it must be able to split to get the bearings on and then pinned with HPGS and thro' time can loosen and cause all sorts of misalignment problems.
It's my opinion and preference to fabricate the crankshafts , glue with industrial glue ( Loctite 603 ) leave to cure for 24 hrs and then drill and ream the webs for 3/32" taper pins, cut out the piece of the main shaft not required and file and finish, this is my preference as against Silver Soldering the webs to the shaft.
This gives a very strong crank shaft with solid Gunmetal outside bearings and 1- split bearing in the middle but it's only my preference and opinion as I prefer to stick to full size practice and don't see the need for needle bearings on our size of toy engines.
I hope this helps but remember, it's only my opinion and everybody is entitled to theirs and if they have the cash to purchase one , go for it..
George.
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Ian,
It's the old adage " if it looks too good to be true it probably ain't " apart from the peculiar position of the lubricator it's never a good thing to make engines without a crosshead on the Con-rods even though the piston rods have long guides and to have needle bearings on the main shaft it will have to be a shaft that's pinned together with grub screws which can create long term problems.
George,
I'm interested to see how these engines hold up without cross head guides- but I can see where the idea has come from, looking at the technology and research that has gone into hydraulic rams, with a super accurate piston fit, honed cylinder liner, long gland/guide length and a proper sleeve packing, rather than wraps of gland packing material. Also, check out the diameter of the piston rods- they seem to be at least 30% bigger than you would normally expect.
A lot of experimenting though, when re-inventing the wheel has been done so many times before.
Greg
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George....thanks I now understand where you are coming from the construction aspect
I can only assume that the engine manufactures using miniature ball or needle rollers & HPGS are also using a LOCTITE super weld medium
[Anton & JMC [in certain engines] have been using ball bearings for approx. 8 years, and recently the BB version of the TVR1A and now the Baylis engine] ...[Saito have also used the fabricated big end & HPGS for 20 years]
Greg...working exclusively with hydraulic cylinders/actuators we have seen over the past two decades greater use if composite materials, lower diametrical clearances and higher pressures
Equating a chemically hardened aluminium material to equal sapphire on the Mohs scale is fine & the way I read the text is that the cylinder head is of aluminium construction, but I do not see a nomination of the piston material, nor any concern of differential expansion due to temperature increase between the dissimilar metals.........................
Cleanliness & lubricity is also paramount with the first slug of steamy water to pass through our engines......
Are the piston rod glands adjustable [for seal wear]? or is it just a mockup?............Derek
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I would imagine these engines will be grossly overpriced, as is all MHB kit. Looking at their twin cylinder engine, it is exactly the same, it looks like they have just extended the bed and made a bigger cylinder block, most of the other parts will be common to both engines, spewed out by a CNC machine, probably under subcontract to an outside firm. I do not like the un supported crossheads, they don't look the part at all, and imagine if the engine had to do any proper work for any length of time the glands would soon be worn and leaking steam. far better to have a trunk guide as in TVR's or Stuart Double tens, or 'slipper' type guides as in Stuart launch engine. I think Stephenson's valve gear looks much better than the Maudsly gear, which is, at the end of the day, basically a camshaft with eccentrics instead of cams. If they are configured as a triple expansion engine, a simpling valve arrangement would be needed to get the engine running as TE's are difficult to self start. Well, thats my twopenneth there are probably those who disagree, but to each his own, They are, as far as I am concerned, the 'bling' of the model steam world.
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That sounds like a lot of unsubstantiated assumptions Nick. If you are going to criticise then you should establish the facts first not just 'imagine'. You seem to have a bit of a downer on the manufacturer.
Colin
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I'm not assuming anything, it would be next to impossible to manufacture these engines without CNC machining, that is not an assumption. The angular forces acting on the piston rods are bound to cause wear with any proper use, by proper use I mean regular and prolonged running, I sail my steamers 6 to 8 hours a week throughout the year, weather permitting, and quite often, when the weather does not permit. As I said, that was my opinion, no doubt others will form theirs. Yes, they will look very nice in a museum quality boat, but for the price they are likely to attract, not a proposition for going to the lake 3 mornings a week. I do not have a downer on MHB, I just think their products are way too expensive......
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I would imagine these engines will be grossly overpriced, as is all MHB kit. Looking at their twin cylinder engine, it is exactly the same, it looks like they have just extended the bed and made a bigger cylinder block, most of the other parts will be common to both engines, spewed out by a CNC machine, probably under subcontract to an outside firm. I do not like the un supported crossheads, they don't look the part at all, and imagine if the engine had to do any proper work for any length of time the glands would soon be worn and leaking steam. far better to have a trunk guide as in TVR's or Stuart Double tens, or 'slipper' type guides as in Stuart launch engine. I think Stephenson's valve gear looks much better than the Maudsly gear, which is, at the end of the day, basically a camshaft with eccentrics instead of cams. If they are configured as a triple expansion engine, a simpling valve arrangement would be needed to get the engine running as TE's are difficult to self start. Well, thats my twopenneth there are probably those who disagree, but to each his own, They are, as far as I am concerned, the 'bling' of the model steam world.
Sorry for the lack of proper quote, the button didn't want to work for some reason!
Firstly, MHB is not overpriced, it is what kit of this quality costs to make and make a profit on top, other manufacturers make lots of models of a good quality and make their margins, just. MHB make a few high-end pieces, that will never lose value, and if looked after are investments in themselves.
If they have extended the bed of the twin and and added a third cylinder they are copying marine steam engine construction methods from the last 150 years, and I'm not really entirely sure what your problem with them doing so is?
I agree, cross-heads do look 'right', and perform their job admirably if made properly, but have can you substantiate your claims with proof that the glands designs and materials they have chosen won't stand the test of time? There are millions of hydraulic applications out there that use the piston and gland as guides only that don't leak a drop at much much higher pressures than our engines work at.
Stephenson's gear is unsophisticated, noisy, inefficient as it wears and requires the friction of four eccentrics to drive it (edit- in a TE, of course, there would be 6 eccentrics), plus loss of energy through the natural errors in the arcs of the die-block. Due to these errors the majority of Stephenson's geared engines have glands that pass water, even in small amounts, this water goes onto the valve gear and fights any lubrication, adding to wear issues. Gear driven valve gears have none of the above, and will give hundreds, if not thousands, of hours of reliable steaming with nothing more than a bit of oil on the gears. On the other hand, through a little thought, MB could have got around the problem of water ingress into the eccentrics from the valve rod glands, but have chosen not to.
Lets see if anyone on this forum gets one and sticks it in a boat.
Where's Kusuchi when you need him....
Greg
Colour changed, as Blue is reserved for the moderating team
Ken
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Here is a translation from Giovanni from a French WEB site....same text...just one or two words translated differently .....
From the original posting here, I had quite some difficulty in understanding how the engine would function without any form of piston sealing element.......Derek
English WEB text
Smooth piston without o-rings. The sealing between the piston and cylinder occurs when the motor is thermally ready to run through the expansion of the cylinder block. In this phase of preheating, the condensed steam can thus escape through the exhaust pipe
French WEB text
Smooth and seamless piston o-rings. The seal between the piston and cylinder happens when the engine is thermally ready for use thanks to the expansion of the block cylinders. In this phase of preheating the condensed steam may escape through the exhaust tube.
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3-cylinder Bore x Stroke: mm. 9 x 12, with a displacement of 4.58 cc.
Difficult being a compound if all three bores are the same. Would suggest that MBH have "rollerised" the shafts to offer the normal bling market an alternative to the TVR. Do you really need needles at 3K RPM? Sealing between pistons and bores if as quoted aren't going to do much for the compressed air fraternity.
Regards Ian.
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Derek,
I am sure that your area of expertise is in hydraulics so can you tell me if you know of any installation of hydraulics where a ram operates at 3000 strokes per min with the fluid at 292deg F( Temp of saturated steam at 45 psi. 3 bar )
Or a scenario where the stroke is 50% less at 1500 strokes per min with the same temperature of fluid.
Thanks
George
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Difficult being a compound if all three bores are the same. Would suggest that MBH have "rollerised" the shafts to offer the normal bling market an alternative to the TVR. Do you really need needles at 3K RPM? Sealing between pistons and bores if as quoted aren't going to do much for the compressed air fraternity.
Regards Ian.
Ian,
Your jacket is on a shaky peg, you've mentioned the dreaded word "B---G" stand back for the slings and arrows.
George.
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George.......
I have not mentioned nor suggested criteria such as "where a ram operates at 3000 strokes per min with the fluid at 292deg F( Temp of saturated steam at 45 psi. 3 bar ", but questioned a previous posting......."Smooth piston without o-rings. The sealing between the piston and cylinder occurs when the motor is thermally ready to run through the expansion of the cylinder block. In this phase of preheating, the condensed steam can thus escape through the exhaust pipe"
We must also understand that a chemically treated aluminium component [cylinder bore] may have an abrasion resistance equating to that of Sapphire...however this may also be only 3 to 5 micron in depth...the substrate aluminium material is still raw aluminium and has the original low strength in resisting mechanical deformation [or toughness]...........
Through 35+ years in marine, military & industrial hydraulics, experience has taught me not rely on chemically hardened aluminium surfacing as a long term benefit ................
Derek
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But George, it does look sooooo pretty? O0
Hydraulic cylinders usually have flexible lip seals and the ends (both body and ram) mounted on pivots so that the operation is in a straight line rather that having side thrust. Even having oil as the filler, it didn't stop anodised components in a Citroen braking system from developing the sticky white sludge of corrosion.
Regards Ian
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George.......
I have not mentioned nor suggested criteria such as "where a ram operates at 3000 strokes per min with the fluid at 292deg F( Temp of saturated steam at 45 psi. 3 bar ", but questioned a previous posting......."Smooth piston without o-rings. The sealing between the piston and cylinder occurs when the motor is thermally ready to run through the expansion of the cylinder block. In this phase of preheating, the condensed steam can thus escape through the exhaust pipe"
We must also understand that a chemically treated aluminium component [cylinder bore] may have an abrasion resistance equating to that of Sapphire...however this may also be only 3 to 5 micron in depth...the substrate aluminium material is still raw aluminium and has the original low strength in resisting mechanical deformation [or toughness]...........
Through 35+ years in marine, military & industrial hydraulics, experience has taught me not rely on chemically hardened aluminium surfacing as a long term benefit ................
Derek
Hi Derek,
I know that you were not questioning the speed of operation but as my background isn't in Hydraulics I asked the question as I don't know how members can relate to full size Hydraulics in our range of model engines where heat is involved and especially those who have never built a " model " steam engine and just wanted to know if you have any knowledge of my question as the engine spec quotes 3000 rpm at 3 bar.
I have built engines using Ali but only as the crank case and pumps from Ali but sleeved with bronze, cylinders and ringed pistons have been from Mehanite grade cast iron of 72 ton quality, poppet valves and seats machined from a Cummins diesel engine exhaust valve to withstand the unknown temps and pressures involved.
I am quite sure that Mr Baylis with his many years of building and selling engines has a good idea of what he is up to, nevertheless there are some design issues with his engine on the mechanical bits, the materials for the cylinder and pistons is not the materials that I would have used but then it's only my opinion which I am quite sure will not concern him.
In your No 18 post you quite rightly point out the adjusting nuts on the piston and valve rods which to me indicate that graphite packing is used.
If a seal such as Silicone "O" rings were used there would be no adjustment as it would effect the groove dimensions for the "O" rings and crush them.
Ian has quoted the use of flexible seals on Hydraulic rams and bodies but can they be installed in such small sizes that we require, I doubt it, hence the use of Silicone "O" rings.
George.
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Hullo George...& I hope I am not getting too far of track here...but must remind members of one fundamental point with old & new technology
We may only be generating steam @ 3 Bar [45PSI] ......but at 150 degrees C & virtually ZERO lubricity ....so we have eliminated the use of....Nitrile to ~~100 degrees C, ...H-NBR to ~~ 150 degrees C...HP & H-PU polyurethane elastomers to ~~ 100 degrees C
We are left with VITON [FPM], silicone & graphite which are suitable for the temperature but have poor strength & abrasion resistance or PTFE products which have no memory - [I have intentionally left out cast iron piston rings which have ZERO compatibility with chemically hardened aluminium surfaces]
I too am sure that young Mr Baylis has investigated the use of newer age materials & metallurgical processes....having said this...I agree that a 3D spheroidal grey engine cylinder barrel with BS1300 bronze piston will never cause a problem if correctly designed, machined & installed :-)) ...........Derek
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Hullo George...& I hope I am not getting too far of track here...but must remind members of one fundamental point with old & new technology
We may only be generating steam @ 3 Bar [45PSI] ......but at 150 degrees C & virtually ZERO lubricity ....so we have eliminated the use of....Nitrile to ~~100 degrees C, ...H-NBR to ~~ 150 degrees C...HP & H-PU polyurethane elastomers to ~~ 100 degrees C
We are left with VITON [FPM], silicone & graphite which are suitable for the temperature but have poor strength & abrasion resistance or PTFE products which have no memory - [I have intentionally left out cast iron piston rings which have ZERO compatibility with chemically hardened aluminium surfaces]
I too am sure that young Mr Baylis has investigated the use of newer age materials & metallurgical processes....having said this...I agree that a 3D spheroidal grey engine cylinder barrel with BS1300 bronze piston will never cause a problem if correctly designed, machined & installed :-)) ...........Derek
Hi Derek,
You are a little off track, all that I wish to know is if you know of any application where Hydraulic rams are operating at 3,000 stroke /min at 292 deg F, is it possible or not ?
George.
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Well yes George.........& to answer you question is a little off track {:-{
Rayathon [USA] designed CIWS [close in weapons systems] gatling guns that are capable of 4,500 rounds of 20 mm diameter projectiles per minute...as used on our HMAS FFG guided missile frigates
In a previous life I supervised the along side shore maintenance & occasional at sea trails of these weapons - they are electro/hydraulic in function....& yes up to 4,500 hydraulic actuator/cylinder component stroke pulsations were sequenced each minute
Your question of temperature @ 292 degrees F is irrelevant in this application...........Derek
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Well yes George.........& to answer you question is a little off track {:-{
Rayathon [USA] designed CIWS [close in weapons systems] gatling guns that are capable of 4,500 rounds of 20 mm diameter projectiles per minute...as used on our HMAS FFG guided missile frigates
In a previous life I supervised the along side shore maintenance & occasional at sea trails of these weapons - they are electro/hydraulic in function....& yes up to 4,500 hydraulic actuator/cylinder component stroke pulsations were sequenced each minute
Your question of temperature @ 292 degrees F is irrelevant in this application...........Derek
Thanks for that Derek,
It's all a bit too testicle for me. I was thinking more of in an industrial application rather than military but I can't see how this would be a comparison to be used in model steam engine design.
George.
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On SY Gondola we have hydraulic application continuous sleeve packing. It cannot be removed or replaced in service, but it doesn't have to. They were installed 12 years ago, and with millions of revs chalked up, they are still in A1 condition.
The packing is a very very tight weave, multi-layered, fibrous (not sure what) graphite impregnated sleeve.
In service the sleeve is installed into a very close fit bore in the gland (I would suggest by the resistance at least +0.0015). The gland nut is put onto the piston rod, the rod pushed through the sleeve packing and the nut brought to bear on the sleeve. Next, you put two hands on the nut and tighten it as far as you can by hand- this is as tight as the nut goes, and no tighter.
After re-installing the engine this year, with a little oil put onto the sleeve before reassembly, they have gone back into service with zero-negligible blow-by.
The piston rods are hard chromed ground mild steel.
Derek, perhaps you could elaborate on what their original application may have been? Dimensions- 50mm L x 40mm ID x 6mm wall.
Greg
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Although I dont like the lack of a cross head. The cylinder may well be using seal-less principles
Either way I would rather buy a lathe and learn to build my own
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Greg...as you suggest they may well be a woven material with graphite or PTFE infusions
There are many on the market depending on the pressure, temperature & surface speed...examples here range from 25 Bar @ 280 degrees C and 20/m per second to 450 Bar @ 550 degrees C
They are generally termed as older style, however totally robust & reliable...they are pressure energised....
Frazer........good luck with considering the purchase of a lathe....however stay away from seal-less principles....... >>:-( .....Derek
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Hi Derek, Iv owned a lathe and made model steam engines for more than 35 years its an addiction with me although I tend to build mainly hot air engines
The seal-less cylinders cannot be that difficult as even Mamod use this idea on there piston valve engines so I wonder if they have simply copied Mamods idea :} as even by there own description of the cylinders workings it sounds very much like it
But I guess until I get my grubby hands on one for repair it will be mere supposition
cheers
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opps...... :embarrassed: didn't realize you were a [35 year+] engine builder Frazer.....
I have no knowledge of Mamod seal less pistons >:-o ...but interestingly viewing a REGNER catalogue it would appear that their steam engines have synthetic moulded pistons which are in fact the piston body & seals in one moulding
With mass production, this in itself would be a very cost effective solution...the only downside I see is lubricity in a brass cylinder bore?????.............
With respect to the original posting......I am not sure where Giovanni sourced his information on the Baylis engine....... Derek
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Hi Derek, no problem I tend to be very shy :embarrassed:
It looks as if the toy makers are catching up with the real world I think the Regnor pistons may simply be that they are using a readily available piston moulding.It is a very good idea in my humble opinion. I don't see a lubrication problem with those pistons they should be able to run dry ??? but without knowing the spec of the polymer its a guess
cheers
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Hi Derek,
I knew I should have taken a photo of the sleeves when they were out! I see the packing you mean is basically a continuous ring of graphite valve packing, the sleeves I am talking about are, basically, a tube, rather than a square section ring. The tube being 50mm long, 6mm wall. I've asked a few people that should have known what they are, but didn't- I was holding out hope that you could have been the missing link to allow me to know what to look for to find spares- s**s law they'll need replacing next year after doing 12 years sterling service!
Greg