Sun-Planet Engine

[vederstein]

Around 1770 or so when Watt was attempting to modify his pumping steam engine for rotary motion, the jerk (and he was an uber a-hole if you read some history...) couldn't get around an existing patent on the slider crank. So instead of paying royalties, he invented the sun and planet gearset to translate reciprocating motion into rotary motion.

After the slider crank patent expired, the sun and planet mechanism for this purpose died as well. I always thought it looked kind of neat.

So after my last failure, it's time to try another failure. I'm starting a design of a small steam engine with a sun and planet gearset.

Here's my first inital concept. It needs a lot more design, but it shows where I'm going...

Comments?

...Ved.



https://youtu.be/gNo8Duqkf_k

 

[Cogsy]

It does look like an interesting design, I'll be following along. Also interesting to hear Watt wasn't a nice guy (I'll go read up when I get the chance). I know of another big figure from engine history who is still revered today but was a truly terrible person as well (I dare not speak his name lest I be lynched by the American members).

 

[kiwi2]

Hi,
I've seen that arrangement on a pump at a local vintage machinery show. The pump looked to be from the early 1900s so the concept survived commercially for at least that long. It was certainly fascinating to watch it work and I thought about trying to copy it into a model only I assumed you'd need a shaper to cut the internal gear. I'll follow your progress with interest.
Regards,
Alan

 

[vederstein]

Kiwi:

It's actually two external spur gears. They are held in position via a "tie bar" behind the gears. The gear attached to the connecting rod is fixed relative to the rod. What happens is the flywheel rotates twice for every cylinder stroke when the gears are the same size.

I have a set of MOD 0.8 cutters, so that's my limitation when it comes to making gears.

Here's a video from a Watt-Boulton engine from 1785...

 

[awake]

It does look like an interesting design, I'll be following along. Also interesting to hear Watt wasn't a nice guy (I'll go read up when I get the chance). I know of another big figure from engine history who is still revered today but was a truly terrible person as well (I dare not speak his name lest I be lynched by the American members).

Edison? Seems like I've heard something about him, but may be getting mixed up with someone else ...

 

[Peter Twissell]

The sun and planet drive has the advantage that the flywheel runs at twice the engine speed, so in theory could be lighter than for an equivalent crank engine.

On the subject of historical figures who may not have been quite the heroes we thought they were - the competitive environment of the indutrial revolution favoured those who were ruthless in their efforts to triumph over anyone who threatened their dominance. It is more surprising that any memorable individuals were anything other than psychopaths!
The Wright Brothers are an exception, although their claim to have made the first man carrying, powered, controlled, sustained flight was helped by interpretation of "powered, controlled and sustained".

 

[josodl1953]

Not to mention the endless law-suits that Otto conducted against anyone that built an engine with only a vague resemblance to the four-stroke engine he designed.

Jos

 

[mirek111]

I'll watch.

 

[kiwi2]

Hi,
Sorry about my earlier post about seeing this arrangement at a vintage machinery show - I didn't fully understand the concept put forward by Ved. What I saw was a gear going around the inside of an elliptical gear.
Regards,
Alan

 

[Cogsy]

Edison? Seems like I've heard something about him, but may be getting mixed up with someone else ...

I hear Edison was a bit on the shady side but the guy I was talking about may have even inspired Hitler (at least he was mentioned favourably in Hitlers' book, received Germany's highest honour for a foreigner just before WW2 and Hitler kept a picture of him in his office...)

 

[davidyat]

Ved,
I was wondering what my next engine would be? I too, have some involute gear cutters to learn how to cut gears. This is just at the right time. I was surprised at how fast the Camgine came together. I think I finished it in a month and a half. I will be looking for the plans when they are ready.
Grasshopper

 

[a41capt]

I hear Edison was a bit on the shady side but the guy I was talking about may have even inspired Hitler (at least he was mentioned favourably in Hitlers' book, received Germany's highest honour for a foreigner just before WW2 and Hitler kept a picture of him in his office...)

Yep, Ole Henry did a lot of good, but having read his book, having read about the history of his son’s treatment, and having made several trips to his museum, I can honestly say he was a smart guy and an anti-Semitic A-hole...

Still,, he did set the industrial world on its ear and put the world on wheels with his inventions...

Would I have sat down and had a beer with him? Probably not my kind of guy!

John W

 

[goldstar31]

Hi John!

I was thinking of Thomas Edison who linked up with Joseph Swan- and lit the World up!

We, that is the 'Geordies' on Tyneside had literally loads of inventors and industrialists.
I think that the best 'funny' were the Liddell family who owned coal mines, lead industries, designed stately homes, railway stations. and translated Ancient Greek in the Lexicon. They also had 'Alice in Wonderland' but I digress. They did have a castle . They were quite greedy and mined under the castle !
They nearly made real aristocracy when 'Alice in Wonderland' but she beat the living daylights out of one of one of Queen Victoria's sons. End of Royal Marriages but Alice Pleasance Hargreaves( nee Liddell) made it in Alice in Wonderland and Alice through the Looking Glass.
I've got a couple of nice photos of the castle of Ravensworth in my hallway- before it sort of fell down!
My connection? Well, I met a little girl with auburn pigtails wearing a blue gingham dress as part of a concert in Newcastle.


As all good stories should end, her daughter and her daughter are coming up to see me. After all- they carry the Liddell gene-- as well as mine!

S&F


Norman

 

[oldCB]

The sun and planet drive has the advantage that the flywheel runs at twice the engine speed, so in theory could be lighter than for an equivalent crank engine.

On the subject of historical figures who may not have been quite the heroes we thought they were - the competitive environment of the indutrial revolution favoured those who were ruthless in their efforts to triumph over anyone who threatened their dominance. It is more surprising that any memorable individuals were anything other than psychopaths!
The Wright Brothers are an exception, although their claim to have made the first man carrying, powered, controlled, sustained flight was helped by interpretation of "powered, controlled and sustained".

Hear! Hear!

 

[vederstein]

Ok, ******** from the 1st and 2nd industrial revolutions:

James Watt
George Henry Corliss
Henry Ford
Thomas Edison
Cornelius Vanderbilt
John Rockefeller
(hell, just about all the robber barons)
Charles Babbage
Joseph Clement

The list of "nice guys" is relatively short:

Richard Trevithick
Glenn Curtiss
Robert Stephenson
Nicola Telsa

(Just my opinions and from the history I've read).

...Ved

 

[goldstar31]

Ah Robert Stephenson and the Royal Border Counties railway bridge- which doesn't separate England and Scotland but goes into Berwick on Tweed which, incidentally is still at war with Germany.

 

[Peter Twissell]

Perhaps it's time for a separate thread if discussion of the merits of historical engineers is to continue.
I look forward to watching the development of the sun and planet engine.

 

[vederstein]

Well, I spent a few hours today on the design. I'm not really liking how it's turning out.

This issue is the eccentric cam. Because of the Sun-Planet setup, the eccentric cam for the engine valving needs geared down by half. This resulted in some alignment issues that I just didn't like.

Here's a picture and video of where I am currently.

...Ved.

https://youtu.be/e-DPSOz852Q

 

[Peter Twissell]

Why drive the valve gear from the shaft (necessitating a 2:1 reduction)?
If the valve cam is attached to the 'crank' (which for copyright purposes is not a crank!) it will run at the required speed.

 

[TSutrina]

The approach would be interesting for a four stroke engine since the valve cam could be on the output shaft and each rotation of the shaft is a powered. What needs to be determined is the weight and size effect.