My Flame Gulper

[MikeR C]

I too built a "poppin". A couple of observations.
Timing was somewhat critical but as it sits it will run in either direction.
If the fuel (flame) shows any yellow it will crud up and quit, now I use 95% ethanol (drinking kind). I tried a butane lighter but after a couple seconds it stopped and would not run till the cylinder and piston cleaned.
The flame position and distance from the intake port is critical, very critical, and the slightest air movement will stop the engine. Occasionally mine blows out the flame as well.
I have an oiler, and I use mobile synthetic motor oil (I think 0w-30w), I was worried that it would be too thick but it warms up and gets "thinner". Once the engine is running I open the oiler and you can hear it speed up.
When starting I rock it back and forth so it sucks in the flame to warm the cylinder, at some point it will begin to oscillate on it's own, then flipping over the flywheel will get it running.
My cylinder and piston are CI, although if I was going to make another vacuum engine I would use graphite. I am very interested in your trials as I have the Ridders plans and was considering building one. Please keep us up to date on the steps needed to get yours running!
Thx
MikeR C

 

[NickG]

Marv,

Funnily enough before I saw your post tonight I went out and tried some 3 in 1 oil on it! I know a lot of people advise against oil but the same happened on my stirling and that was one of the things that it required to run, and plenty of it.

Unfortunately still no signs of life but I don't think the oil increased the friction or drag in the system, if anything I do think it helped a bit and helped seal it better, it was blowing the flame out a lot when I was trying to start it.

On the timing I think you're right. I think the design of this internal valve version is marginal because one can't adjust the timing of the valve closing as well as with a cam actuated valve. Well I can get it to close earlier by making the striker longer but, I think the 'phenomonen' that occurs when the valve closes before BDC in your type of engine and the piston is still travelling down bore helps when it get's onto the back stroke - using some of the stored energy in the flywheel to create a partial vacuum then it gives it a helping hand once over BDC?

Mike, thanks for your input too. Before I tried the 3 in 1 I was thinking 0w30 would be about the best as that is about the thinnest available and it's obviously capable of withstanding high temperatures.


Next job is to make the burner so I'm not holding it as everybody has said it is very critical, it won't help with me moving it around - especially it seems now on this internal valve type. I will need to make it in such a way that it is easy to adjust the position and size of the flame.

Thanks again for the advice and support.

Nick

 

[mklotz]

Another thing that concerns me in your design is the mass of the valve piston. Unless it's hot and stays hot, it will act to quench the hot gas. (Poppin uses a bit of feeler stock as the valve so its mass is miniscule.)

When you preheat the cylinder, do you preheat the valve piston as well? If not, give that a try. I may be daft here but it won't cost anything but a bit of time to try.

 

[rake60]

I have two builds of that engine here Nick and have never been able
to bring either of them to life. This thread is certainly giving me new
ideas to try.

Thanks for the play by play updates!

Rick

 

[deverett]

Regarding light oil for lubrication, has anyone tried Marvel Mystery Oil (or Redex in UK) or is that not a lubricant?

I have no opinion on its use, just asking in case I decide to take the plunge one day on this type of engine.

Dave
The Emerald Isle

 

[putputman]

These are my two flame eaters. The "poppin" style has a graphite piston in it. It runs very well & the speed can be controlled by position of the flame.
The timing is set so it run clockwise. You can't even spin it in a counter clockwise as the valve would be in a closed position.

The Jan Ridder design engine also has graphite pistons. The way it is valved it will run in either direction. (if & when it runs)


I went up to the shop today to photograph the engines and I thought I would give the Ridder engine another try. (haven't tried it for the last year)
I warmed it up for just a couple minutes, spun the flywheel and it run for a short time. I took a video and you can see just about the total run. I tried for another half hour and couldn't get it to run again. Just like the last time it ran. ??? ??? ???

I did notice the flame is very orange. It is denatured alcohol so I thought it would be a clearer flame.


Not sure what the next move will be. Maybe Nick or Rick will come up with something.

 

[MikeR C]

Steamdave, the oil in the lubricator in the pic I posted is Marvel Mystery oil. I switched because Marvel is made to burn and I wanted to avoid that.

NickG,
Please do not take this the wrong way, but, did you look at jan's trouble shooting guide? He seems to be very picky about flame placement as well...

http://heetgasmodelbouw.ridders.nu/Webpaginas/pagina_happer_inw_schuif/inw_schuif_frameset.htm

 

[NickG]

Marv,

Another good point. I have tried heating it also, but you might be right. Jan's design is hollowed out I think. think his piston is as well. If I find I have to go the route of making a new piston and valve, I will hollow them out to reduce any heat sink effects. Do you think the gases are quenching before the valve is closed?

Mike, yes I have followed the trouble shooting guide - all seemed ok.

Putputman, thanks for the video, I can't view it on this computer but will do later.

Nick

 

[modeng2000]

Yes Nick, both the piston and valve are hollowed out.

Don't get too downhearted, I can't get my version to run reliably now. It did when first fired up but it is behaving just like all the others now.

John

 

[NickG]

Putputman,

Just saw the video - well done because it was running beautifully for a while but can't think why it stopped unless the flame is being blown around too much, or friction changed as it got hotter. The cooling should be sufficient because there are 1 or 2 out there that keep running. Very strange - I was even getting frustrated with yours then :big: You've done amuch better job than me that's for sure as mine doesn't even try!

Nick

 

[putputman]

After reading MikeR C's post I downloaded Jan Ridder's trouble shooting guide. That wasn't available when I built mine a year ago or so.

When I get some time I will follow his procedure to see if engine meets his standards for fit & finish.

I got to say that Jan Ridder is some kind of a master when it come to understanding & building engines. I think if we all follow his instructions we can get them all running.

 

[NickG]

Mine passes all that criteria but still no joy. :-\ I am going to do the base and make some sort of burner that has an easily adjustable height & position then keep trying.

Nick

 

[modeng2000]

I am beginning to think that mine will end up as an ornament!

John

 

[jimmyocharlie]

I don't want to start an argument but let me interject a bit from my own experience.

Senft's "Poppin", which I built a number of years ago,

calls for an oil feeder cup on the top of the cylinder. I included it and use it.
There can be a considerable amount of oil in the cylinder and the engine runs flawlessly, though I do need to preheat the cylinder to get it to start quickly.

Poppin has a very fast-acting valve operated by a cam on the crankshaft. This allows it to, after some hot gas is ingested, get the cylinder closed very rapidly so that the gas doesn't have a chance to lose much of its energy to the cylinder walls. I have to think that Senft, no dummy he, chose that design because he understood the problem of rapid gas quenching that arises in these models. I have an unproven suspicion that many of the problems with these engines have to do with early gas quenching and not friction. This is somewhat substantiated by the sensitivity to flame placement.

is that an ally barrel? i

 

[mklotz]

If "barrel" means cylinder, then, yes, it is aluminum.

 

[putputman]

A RAY OF HOPE

I went up to the shop again today, for something not connected with engines, & saw the Ridder flame sucker setting on the workbench. Just for "sh.ts & giggles" I thought why not try it again.

Before I put a flame to it today, I spun the flywheel over, and the engine made a popping noise similar to the "poppin engine". I don't recall it ever sounding like that before. It is possible that the run yesterday left a film on the graphite piston or in the cylinder that tightened any gap between the piston & cylinder. Just a guess.

To give the burner a little more flame I pulled out more wick, lit it and let it set next to the cylinder for a couple minutes to warm it up. It had a larger flame than yesterday. After giving the flywheel a spin a couple time and adjusting the position of the flame, the engine came to life. It started running fairly slow and then picked up speed. It got fast enough so that the valve & piston would bounce once in awhile and throw the timing off and slow down a little. Acted just like a governor. After about a minute of running like that it settled down to a nice even rpm and ran that way for about 4-5 minutes. I stopped it and spun it in the other direction and it ran for another 2 minutes and started to slow down & finally stopped by itself. By this time, the cylinder was so hot I couldn't hold my hand to it. There must be a optimum temperature for this to run.

I wish I could tell you what the secret is to get these engines running, but I honestly don't know why this things runs sometimes and not other times. I hope my experience will give the rest of you enough determination to stick with until you get them all running.

I will try again tomorrow to see what kind of mood it is in.

 

[cobra428]

putputman,
Congrats, I heard those flame eaters where a bear to get going. Looks like your on to something!

Tony

 

[jimmyocharlie]

If "barrel" means cylinder, then, yes, it is aluminum.

thanks
i'm toying with the idea of aluminum cylinder and piston on a flame gulper ??? ???

 

[NickG]

Putputman,

Many thanks for trying and posting your progress. This is helping with troubleshooting greatly. Well done on getting yours running. I think you might have hit the nail on the head, the seal between the piston and cylinder. I doubted my fit between these components when I first made it but thought i'd give it a try. it's obviously a fine balance between getting a near perfect seal and low enough friction. The only thing is, I've tried it with oil which should make it seal, and it didn't seem to increase friction although I know some people swear blind oil prevents them from running (including the designer) but I've seen oil used with them before and Marv states that he uses oil, infact as he says, the poppin design incorporates an oil cup!

glad you've got yours working though, gives me a glimmer of hope!

Nick

 

[mklotz]

i'm toying with the idea of aluminum cylinder and piston on a flame gulper ??? ???

Al on al will lead to galling. Not a good choice. Use dissimilar metals.