Philip Duclos Fire Eater

[werowance]

and I should say my first graphite rod from ebay was just a stir rod and it was aweful and pourus full of voids. and not to mention cost me just as much as the real deal machinable graphite. so id stay away from the stir rods on ebay.

 

[fcheslop]

Hi Bob, the videos as promised
You can see how worn the valve gears has become
She is running a bit slow as its gummed up after a couple of years collecting dust
You can see they are not to fussy about flame position unlike the Ridders engines

 

[CFLBob]

Thanks, Fraser. Yours runs fantastic.

What I'm going to focus on now is the sound. I don't know what to troubleshoot because I have no idea what makes that sound, but yours sounds different. Comparing it to the sound of my video in post 172 shows a different sound. It's both shorter duration and higher frequency.


Bob

 

[Tim1974]

Thanks, Fraser. Yours runs fantastic.

What I'm going to focus on now is the sound. I don't know what to troubleshoot because I have no idea what makes that sound, but yours sounds different. Comparing it to the sound of my video in post 172 shows a different sound. It's both shorter duration and higher frequency.


Bob

Where talking Stirling I take it ? I hope to find out haw to make for speed and power any hints ?

 

[CFLBob]

Where talking Stirling I take it ? I hope to find out haw to make for speed and power any hints ?

These aren't considered technically Stirling engines. They're atmospheric engines because the atmospheric pressure works over half the cycle.

I think. I'm really not expert at this sort of stuff, and I've never built a Stirling engine.

 

[CFLBob]

Found these old pics maybe not much use but you can see the piston position at TDC and BDC and also a mark that shows how the valve just covers the port
View attachment 104110 View attachment 104111 View attachment 104112 View attachment 104113

Fraser, this might be a personal record for me being dense, but in the third picture, that's the top of the piston visible in the cylinder opening?

Mine isn't that far forward.

A quick check shows the crank and the push rod are the right lengths. I don't see what I got wrong, but if the system doesn't compress enough, this is never going to play.

 

[minh-thanh]

Fraser, this might be a personal record for me being dense, but in the third picture, that's the top of the piston visible in the cylinder opening?
.

The piston visible in the cylinder opening !
The pistons must move near the cylinder head - but do not touch.
It must push the gas out of the cylinder and draw hot air from the flame

 

[CFLBob]

The piston visible in the cylinder opening !
The pistons must move near the cylinder head - but do not touch.
It must push the gas out of the cylinder and draw hot air from the flame

I'm really confused about this. I just measured every dimension that affects the position of the piston and every one is right. My piston seems to be 1/8" too far down the cylinder possibly a little more than that. It's hard to measure.

I can understand how to make the piston move farther up the cylinder. I could move the flywheel and the cylinder closer to each other by moving those holes in the base plate. I just don't understand how everything can be built properly but the position be so wrong.

 

[fcheslop]

Hi Bob, youre assuming youre engine is wrong I simply dont know if my engine is correct, Although now you pointed it out I think I didnt set the engine up as per the drawings but its such a long time ago I have trouble remembering what I did yesterday let alone 20 odd years ago.
I would try a simple test for the valve and port face
Disconnect the conrod from the crank then turn the engine until the port is full covered
Pull the piston down the bore reasonably quickly and let go.It should snap back up the bore and may even hit the head with a bump. If thats ok then start looking at the timing
The piston on my engine also comes out of the bore by about 1/16 to 3/32 and as you say half covers the port at TDC
Tim these are vacuum engines and as far as I know have no connection to the Stirling engine .If you want to start a thread I would gladly help in anyway I can and have built far to many of these engines for my own good with and without speed control
cheers

 

[CFLBob]

Hi Bob, youre assuming youre engine is wrong I simply dont know if my engine is correct, Although now you pointed it out I think I didnt set the engine up as per the drawings but its such a long time ago I have trouble remembering what I did yesterday let alone 20 odd years ago.
I would try a simple test for the valve and port face

There's one big difference between yours and mine: yours works. It's possible the problem with mine is something else, but this is relatively easy to test.

Disconnect the conrod from the crank then turn the engine until the port is full covered
Pull the piston down the bore reasonably quickly and let go.It should snap back up the bore and may even hit the head with a bump. If thats ok then start looking at the timing
The piston on my engine also comes out of the bore by about 1/16 to 3/32 and as you say half covers the port at TDC
Tim these are vacuum engines and as far as I know have no connection to the Stirling engine .If you want to start a thread I would gladly help in anyway I can and have built far to many of these engines for my own good with and without speed control
cheers

I can't measure it right now, but mine comes out farther than that. Still the extra 3/16, I think.

The easy test is to slot the screw holes in my base so that I can slide the flywheel and crank 3/16 closer to the cylinder. A perfect example of the kind of job that takes as long to set up for - or longer - as to machine. Unfortunately, I have some commitments tonight so I'll have to reassemble it tomorrow.

 

[Engine maker]

I built one years ago, set the cam in the middle of the slot and it fired right up, runs faster than most too! I did notice that it likes a very WIDE tall flame. You might try spreading the wick out some. I had a friend that had one that would not run and all it needed was more fire! Give it a try.

 

[CFLBob]

I built one years ago, set the cam in the middle of the slot and it fired right up, runs faster than most too! I did notice that it likes a very WIDE tall flame. You might try spreading the wick out some. I had a friend that had one that would not run and all it needed was more fire! Give it a try.

Thanks! That goes on the list to try.

 

[fcheslop]

Hi Bob, Iv just checked the other Duclos design Little Blazer and the piston come about a third into the port hole
cheers

 

[Gedeon Spilett]

Looking at the video on post #172, I feel that movements are not free enough, we also hear the friction noise ( the valve and the spring?) that you have to fix...hidding the popping and farting noises, you must have !

 

[tim]

hmm really love your work i hope you get it running i will consider this as my next project i like the look

 

[CFLBob]

Just an update after moving the flywheel and everything mounted on its shaft closer to the cylinder. The top of the piston is now about 1/16" past the back of the opening, so I moved it about 1/8" inch farther into the cylinder. I cut slots for the SHCS mounting screws in the bottom of my mounting plate.

This splits the difference between how far the piston is in front of that edge of the valve opening and how far it hangs out the back of the cylinder. It hangs out of the back about the same amount, 1/8".

I've tentatively concluded that the piston is too small, and ordered a graphite bar from Becker graphite (thanks, werowance) to make a new piston. I've tried to run it after preheating the cylinder but not without doing that. If it's true that these engines either run hot or cold due to critical clearances, it might make a difference.

Here's a short video I shot that shows if I move the flywheel fast, as if trying to start it, I get some sound, but if I move it slowly I don't. Fraser's video shows sound when moved slowly. Since pressing the valve against the cylinder didn't affect this, but if I try to move the flywheel CCW quickly it seals and prevents the flywheel from moving, I'm thinking the piston is most likely the problem.



Comments appreciated, of course.

 

[minh-thanh]

Just an update after moving the flywheel and everything mounted on its shaft closer to the cylinder. The top of the piston is now about 1/16" past the back of the opening, so I moved it about 1/8" inch farther into the cylinder. I cut slots for the SHCS mounting screws in the bottom of my mounting plate.

I do not know why there are piston position differences at TDC between how you do and fcheslop said!
But the piston needs to push all cold air out of the cylinder

Here's a short video I shot that shows if I move the flywheel fast, as if trying to start it, I get some sound, but if I move it slowly I don't. Fraser's video shows sound when moved slowly. Since pressing the valve against the cylinder didn't affect this, but if I try to move the flywheel CCW quickly it seals and prevents the flywheel from moving, I'm thinking the piston is most likely the problem.
Comments appreciated, of course.

-- the piston is most likely the problem : maybe
--- or maybe :
valve is not seal (valve surface and surface of hole air intake are not straight)
or valve does not completely cover hole air intake .
or all three of them

 

[CFLBob]

-- the piston is most likely the problem : maybe
--- or maybe :
valve is not seal (valve surface and surface of hole air intake are not straight)
or valve does not completely cover hole air intake .
or all three of them

Ran another test. I let the engine cool off for about three or four hours and then tried it again. It actually turned over and ran for about a second. Couldn't get it to run after that.

The reason I tried that without preheating the cylinder is thinking that if the problem is the piston being slightly too small, I should test it when the cylinder is as small as it can be. Preheating the cylinder makes the fit worse, so it has the best chance of working when the cylinder is cold.

Well, I probably won't have my graphite rod for another week, so I have time to repeat this and look at other things.

 

[werowance]

might try icing the cylinder to just for grins and giggles while you wait on the graphite. what you are describing is exactly what my flame eater was doing, a little oil in the cylinder helped but would of course gum up as soon as it got to the smoke point of hot which happens pretty darn fast. also on the fuel, I use denature alcohol which I get at the hardware store. it actually even says "fuel" on the can below the denatured alchohol part

 

[werowance]

also on my flame eater, adjusting the piston to just barely past the port opening like you have it now vs it coming to the edge but not past didn't make a difference on mine once I got it running. but while trouble shooting and fighting with it, it did seem to maybe turn over a couple more times with it just past the intake port than without, just enough to give me false hope that it was going to run. the design of yours and mine are not that much different, key thing is your valve operating and covering the outside of the intake port whereas mine is covering the inside of the port, the cylinders look very similar so I'm hoping for you that its just expansion rate. sure would make me happy if that's all it is.