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 Fell diesel locomotive

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ralphbrades




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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptySun Sep 25, 2011 4:02 pm

I don't know if this is going to work! But as requested Anton -here is the Fell under test.

The first part shows the cooling system running up -note the pump and fan flapper moving.

The second part shows the torque convertor being flooded and drained by its pump.

The third part (and I nearly screamed in frustration!!!) shows the torque convertor JUST at the point of solidus and the gear box moving. Any more throttle everything vanished into the blur and any slower nothing moved....

https://www.youtube.com/watch?v=asnLCNDAB2E

Lets hope it works!

regards

ralph
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antonr91

antonr91

Location : south-east England

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptySun Sep 25, 2011 4:32 pm

Ralph, i must say you have one extremely fascination machine there. Im not 100% on what everything is, but it looks impressive. I keep forgetting that yours is a larger gauge, 3 1/2 inch??

How powerful do you think it would be? enough to be pulled along by? Wink Very Happy


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ralphbrades



Location : Derby UK

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptySun Sep 25, 2011 5:26 pm

Anton:

The Fell is a Gauge '3' loco and thus pulls model carriages and wagons -not people. The gauge of the track is 63.5mm=2.5 inches. What you were looking at was the first "power' test. I now have to adjust the fluid viscosity rates to fit the torque curve -this is done by dropping a ball bearing down a length of glass tube and timing the time between two pieces of tape 30cm apart.

Now that I have had "good" power test I have to build the plumbing around it. This is not going to be easy and some "inspired" work with a pipe bender is going to be needed!

I am glad you enjoyed the sequence -I have never uploaded anything to YouTube before -let alone used iMovie on my Mac....

regards

ralph
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ralphbrades



Location : Derby UK

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptyWed Sep 28, 2011 4:32 pm

Well after dire threats I managed to drill a suitable expansion hole in the torque convertor. The one problem that I expected was heat. And this I got in barrow loads. What I did not expect was HOT FOAM. The dissolved air in the fluid was basically beaten out of the fluid and the cutesy pink froth returned to the reservoir. I had expected some "whipped cream" effect -but to be honest not a complete bubble bath...

Since the foam is compressible, whilst the fluid is not, very little happened whilst it was foaming at the mouth so to speak. So, what I have done is to drill a port at 45 degrees from the front face and inserted a length of 4mm pipe to as close to the centre of axis of rotation as I can. Now (hopefully) when the torque convertor fills and froths all the froth will rise to the axial centre of the torque convertor and thus be expelled by the rising fluid. This does mean that I will have to block off the drain from the torque convertor and thus force all the froth and fluid through the central port until I get "clean" fluid coming out of it. How this will be done during the test tomorrow afternoon will be via applying by hand a pair of surgical clamps on the tubes. I know how long it takes to completely fill the torque convertor cavity -so it should be possible to set a timer circuit to change over from axial port to radial port after the cavity is filled.

More Work (sigh)...

I have three batches of fluid ready for testing tomorrow (YES the Goldilocks principle!)
One is as thick as I think I can pump it.
Two is a solid as can make it between the viscosity temperatures.
Three is a 50/50 blende of one and two...

I will see if I can make a small video for you Anton!

regards

ralph
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antonr91

antonr91

Location : south-east England

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptyWed Sep 28, 2011 7:43 pm

Ralph, i am getting more and more interested in this projectof yours with each post you do. I need to start with the concept. So could you explain to me, exactly how a diesel hydraulic loco works and how it differes to direct drive and diesel electric.

Sorry but i know nothing about it and would like to be informed.
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ralphbrades



Location : Derby UK

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptyThu Sep 29, 2011 6:30 am

The Mekydro and Voith systems are the most common types of hydraulic transmission. I have based my design on the Voith L35 system -as there are a few in the scrap piles of the preserved railways that I visit! Instead of a dynamo or alternator the engine drives a centrifugal pump (the impeller) this produces a mass of rotating fluid the fluid then is directed at a set of moving blades that are forced to move (the driven plate). Pretty much in the same manner that a drill pump turns a water wheel!!!

The beauty of the hydraulic system is that you can alter the amount of force that is transmitted by the driven plate either by increasing the amount of fluid being moved or changing the shape of the driven plate. The first is used by the Voith system and the latter used by the Mekydro. At certain speeds and pressures fluids can be made to be "non-Newtonian" the most famous of these are custard or ketchup... The fluid becomes a "solid" and directly transmits the force between the impeller and the driven plate. It is this same principle that allows Icelanders to commute across the Pritipal River by snowmobile -provided the snowmobile is going full thrust the water acts just like solid snow and you bounce across the river!!!

The problem with this is that the non-Newtonian aspect of the fluid only exists between certain pressure and speeds limits. So, in order to increase the amount of torque that you achieve you EITHER have to have multiple torque convertors for different speeds (the Voith system) or you have a method of varying the pitch of the driven plate (the Mekydro system).

If you take the idea that the hydraulic transmission system is not unlike using an engine driven fan to turn a wind turbine to extract the power from it then you are not far off the mark. The fluid used is an oil rather than air and the wind turbine can alter the pitch (Mekydro) or you can have a set of wind turbines all specific to certain wind speeds (Voith).

The "maths" behind it is pretty nasty as the efficiency of the transmission is related to the FIFTH power of the rotation and the FOURTH power of the diameter. This means that the faster you turn it the more torque you get out per rev. The wider you make it the better it is. The problems of centrifugal forces begin to raise their heads and you then have to design/cobble together a system that will take the forces involved.

Getting a design that has not leaked under 600 plus G and has not "exploded" has been a problem!!!!

regards

ralph
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Carl Hibbs
Admin
Carl Hibbs

Location : Haute Normandie - visitors welcome

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptyThu Sep 29, 2011 9:09 am

Very imformative Ralph.

Hope you get yours sorted.

But after all that you can now see why I went with electric transmission!

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antonr91

antonr91

Location : south-east England

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptyThu Sep 29, 2011 10:45 am

WOW,

Never understood it before, but Ralph, you are extremely good at explaining things, especially as i now have a much clearer idea of what you are trying to achieve. Well i say fair play to you, as it seems your are not put off by things going wrong and you are determined to get it working and functional. Smile

Cant wait to see it working now. Do you think that once you have built this Guage 3 model, you could build the same thing on a smaller gauge like 45mm/32mm?

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ralphbrades



Location : Derby UK

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptyThu Sep 29, 2011 4:16 pm

Well at the end of a massively bad afternoon here are the results...

One -was too thick to pump -it may in fact have been this that broke the pump...
Two - was "neither here nor there" from the standard mix that I have been using. Maybe it "came on" faster than the normal stuff but is difficult to tell(?)
Three -was maybe better at pumping and it felt "softer" than Two as it came up to solidus.

So, I now need a new pump for the torque convertor -this is not unexpected as the poor thing has been sorely abused since its purchase!!! It is is of the twin gear type and well it is missing a few teeth -rather like me.

Anton:

Thank you for your kind words -there have been times when the plants near the test zone have been practically beheaded by leaks -try to imagine it 1.2 litres per minute at 600 G...

Carl:

Yes I know that electric transmission is far easier -but you have to understand the importance of this loco to me. I had to build it -because it was so wierd. Everything about was "wrong" and as I looked at it more and more the feeling grew to mammoth proportions that I had to build it -because no one else would!!!

regards

ralph
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KleineDicke

KleineDicke

Location : Deep in the Heart of Texas (Houston)

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptyThu Sep 29, 2011 5:53 pm

Good luck, Ralph. As your experiments have demonstrated, hydraulic transmissions are not for the faint hearted! I am amazed you've gotten as far as you have. It's gone way beyond a project now; its a crusade.

For some reason, the Germans loved hydraulic transmissions for locomotives (maybe because of the complexity? Laughing ) but they never worked well in the US.

_________________
Bill Wray

"It is one of the happiest characteristics
of this glorious country that official utterances are invariably
regarded as unanswerable."
-Sir Joseph Porter, First Lord of the Admiralty (HMS Pinafore)
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ralphbrades



Location : Derby UK

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptyThu Sep 29, 2011 5:57 pm

Right. E-Bay has sold me a new pump for £4 plus P+P. And after the weekend I should be back in business.

Anton -as to building a small scale hydraulic loco the answer is probably "no"...

I do know that Bob Symes built a hydraulic at Gauge 1 and to be honest I think this is perhaps as small as it could go. I have a 60mm wide torque convertor in a 120mm loading gauge width. If I crib some dimensions then it might be possible to fit a 60mm one inside a 10mm to the foot scale model. A 16mm scale model running on 45mm track would present very few problems and a 7/8ths scale one would be even better!

I have to return to my plumbing problem, now that it works all the silicone plastic piping has to be replaced with curved copper with clamp fittings -rather than "wiring them tight". This is where things get to the level of "inspiration"!!!

regards

ralph
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pjti



Location : Galizano, nr Santander, Nth Spain

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptyThu Sep 29, 2011 7:20 pm

Totally amazing Ralph. Must put you up for the New Years Honours list. Good Luck for the "Glorious First".

_________________
Wake me up by noon please.

Patrick
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antonr91

antonr91

Location : south-east England

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PostSubject: Re: Fell diesel locomotive   Fell diesel locomotive - Page 3 EmptyFri Oct 26, 2012 10:34 am

Hi Ralph, just wondering what the latest is with this creation of yours? as im sure i can speak for a few of us..we are eagerly awaiting some more news and info Laughing
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