Raleighcopter

A phase locked loop could get you 10 pulses out of a single rpm pulse fairly easily but your mechanical solution works so it's not wrong. Well done, bert.

1967brutus

To illustrate:

Preliminary and very crude consumption checks seemed to indicate approx 24 ml of fuel per hour on the pond.
A test in my bathtub, at near continuous full throttle made 15 ml last for more than one hour.
Which means that either my crude preliminalry measurements were way off, OR the engine load is significantly less in the tub compared to on the pond...

Either way, this kind of consumption, well, it is utterly minimalistic...

1967brutus

Forgive me my ignorance but what is a phase locked loop?

Raleighcopter

It's an electronic circuit that generates multiplied frequencies, used a bunch in radios and television s and now in computers. It essentially would fill in the 9 missing pulses between the one rpm pulse you have using an arduino's timers and a bit of math. 3.5 khz is pretty easy when you have a 48MHz clock like the one in the seeeduino Xiao.

Edit: it's actually 350 Hz so it could be done with even an Arduino nano or similar

Raleighcopter

https://en.m.wikipedia.org/wiki/Phase-locked_loop

1967brutus

I do have 10 pulses per revolution. The GV1 needs that for some dumb reason...

1967brutus

I was wrong about that... Assumption is the mother of all ****-ups, and "I believe" is the father of the lot: Where I saw 100 to 110 deg C by IR gun, after installing the fan, that dropped to 70~80 deg C, and I could touch the valve cover with bare finger, which I could not before.

So tiny or not, HUGE effect... I sure did not expect that...

Raleighcopter

I wonder how big of a fan I'd need to cool my ft120ii? Then I could build an rc VW Beetle.

How cold is it in your shop?

Glowgeek

When I turned 11 I got a Cox Baja Bug for Christmas. My brother and I had a ball with that thing.

John_M_

Bert, those videos remind me of the old "Hit 'N' Miss" engines... looks like you got it running reliably... after 7 years, I would have lost interest ... looks like a lot of fun.

Whatever happened to the stirling steam engine you had? that looked interesting as well.

1967brutus

With the proper ducting, not really big... Look up "Vario SkyFox Boxer"...

My shop is just ambient basically, right now around 10 deg C

1967brutus

I only ever dreamt of having one of those. They were sold by Graupner, but very few modelling shops ever had them in stock, and they were fairly expensive.

1967brutus

I did not spend 7 years tinkering... The project has basically been domant for 7 years, but somewhere in the back of my mind a few tiny cogs kept spinning, slowly... Until something clicked in place and the project got a new impulse. And here it is...

It's not hit&miss, it's properly carburated and throttle-regulated.

The steam engine (not stirling, that's a different operating principle) is running fine, and has been gradually developing ever since. It's got a faster boiler feedpump now, and regulated electric heating on the fuel tank to maintain more constant gas pressure, and now it can either run balls-out continuously (24 minutes until empty) to deadslow continuously (75 minutes) and anything inbetween at will, fully automated and alarmed.
It's a delight to operate.

I will have to update that thread, I noticed I did not post latest developments there. Apologies.
The steam engine currently has about 57 runhours, which frankly, is quite a lot as these things go, most people run them 4 or 5 hours per year... Not me though

John_M_

I know you didn't, I just stated that because you're like a dog with a bone, you keep gnawing away on your projects until you find a solution.

I can see its carb / throttle managed... just the slow putt putt sound reminds me of the hit n miss .

That steam engine looked like it was well made... I have a fancy for anything thats done to scale with detail... My neighbor is into model trains, "G scale garden railroading"... his entire backyard looks like the old time Colorado railroad from back in the day, right down to the scale buildings, crossings, and landscaping... he has a couple G scale live steam trains he runs, just amazing detail.

1967brutus

It still does...

In the past 2 months, I managed to fit the boat with a feedwater preheater annex condenser, that preheats the water pumped to the boiler to approximately 90 deg C, resulting in a considerably (10% or so) lower fuel consumption for the same output. That preheater/condenser also returns about 40% of the consumed water back to the feedwater tank, resulting in a longer operating time. On this scale, barely anybody does that. Another one of those things that I kept gnawing at

https://www.modelbouwforum.nl/attach...-1-jpg.554978/

https://www.modelbouwforum.nl/attach...-1-jpg.554979/

https://www.modelbouwforum.nl/attach...-1-jpg.554999/


Catching all the oil from the condensate initially appeared to be a challenge, but once I figured out what was the issue, it actually was surprisingly simple.

I think I have now about 25 hrs of runtime on this set-up, and operation has become extremely simple and troublefree.

Raleighcopter

That is absolutely fantastic.

Glowgeek

The boat and steam engine look great. All that plumbing looks cool.

What is the boiler fueled with? Esbit?

John_M_

My neighbor uses methenamine in his live steam trains, same stuff as esbit... back when I was just a kid, I had one of those Wilesco table top steam engines... when I ran out of the solid fuel tablets, I would pack the fuel tray with cotton balls and soak it in alcohol.

1967brutus

30/70 propane/butane mix, over a proportional valve that is hooked up over telemetry to the boiler pressure, resulting in a boiler pressure tightly controlled between 1,4 and 1,55 bar.
The fuel tank is electrically heated, heat (5W) is switched on and off on gas tank temperature, in oder to have a somewhat consistent fuel pressure, which makes the job of the boiler pressure regulation easier.

The thing with steam is: the more consistent you can get it, the better it works. "Steam" hates changes in operational conditions, so the better everything responds to each other, the smoother the system functions.

It's rather "organic", actually: Everything affects Everything...

Glowgeek

The extent of my experience with model steam engines is a "dampfmaschine" my father picked up used in Germany. It came with a couple of belt driven accesories.....a wood chopper guy and two guys operating a two-man crosscut saw. My brother and I burned ourselves.......I mean...... had a great time with that toy.

1967brutus

That HAS to have been a Wilesco stationary set... They were pretty popular here as well when I was a kid, but pretty expensive too... Not many parents could afford that kind of X-mass present for therir kids.

Strange enough (they are still being made) prices have not kept up with inflation. Forty years ago a Wilesco steam roller would set you back about 250 guilders, now they are about that in Euro's, but 250 guilders in the '80's is closer to 500 euro nowadays, if not more.

Glowgeek

Yes, a Wilesco D5 I believe. The thing wasn't balanced very well and would start skidding across the work bench when at full bore. We took turns sacrificing our arms to the boiling hot spewing splatter coming from the cylinder. Lol. Those were the good times.

John_M_

Mine was a D10 I believe... still available, $225 for the std D10... they have a 100 year anniversary version of the D10 for $275... not a bad price for this day and age... the larger models that have silver bazed boilers are a bit more expensive, 1k to 7k USD.

https://www.ministeam.com/product/Wi...-Steam-Engines

1967brutus

Fuel consumption confirmed on the pond (meaning a free running boat) as I consumed 10 ml in 40 minutes. Engine did not miss a beat.

It still amazes me, how absolutely tiny those droplets have to be.

Anyway, a short impression of this other department of ex-glow gasoline powered RC modelling:

(apologies for the portrait format, I did not hold the camera...)

Raleighcopter

now i feel like i need to break out my RC sailboat model.