What material to use in a Flame Licker?

[Shipdisturber]

Since I found this website I want to build everything in, but alas I need to focus on one thing to be able to finish it. My question is what materials can be used to make the piston and cylinder? Cast iron is not easy to find for an available machining stock but brass, aluminum, stainless steel, mild steel, copper and hardwood are. So of the above materials what would be best?

 

[fcheslop]

Out of that choice i would go for stainless steel although both the Duclos engines Iv built have alloy cylinders with bronze pistons using graphite dust to lubricate them
Iv used graphite for pistons in the past with good results .Iv also used EN1A PB for pistons with no problems
Cast iron cylinder and piston would be my first choice as the expansion rates will be identical and it has good wear and lube properties
Just my two bobs worth Im sure others will have more ideas
cheers

 

[Shipdisturber]

I'm thinking that Stainless may not be in my best interest, I'll have to see if I can get some locally.

 

[Blogwitch]

S,

You are trying to build one of the hardest engines there is to get running, and I think having to ask what to use, you might be letting yourself in for a lot of heartache.

They look simple enough, but the wrong materials for piston, cylinder and sometimes even the slide valve can contribute to an engine never running.

I have seen people build from respected plans and still not been able to get them to run, even with the correct materials stated on the plans.

Because of the very low powered ones producing so little power, friction can be just one of the reasons an engine will not run. You can get away with odd material mixes on other types of engines, but not on a smallish flamelicker, mainly because of the lower tolerances of the piston/bore clearance to produce that vacuum, where expansion rates come into the formula.

If you can't get cast iron for both (best recommended material) then you will have to do a fair amount of experimentation to get a runner, even then you might never succeed.

I have plans for larger flamelickers, and they use steel tube for the cylinders and cast iron for pistons, but only because they produce more power than their smaller counterparts and can cope with the extra friction produced because of dissimilar metals for those two items.

Big lickers here, where the flywheels are sized at 10" and above, so you can see how large they are.

http://www.gerd-litty.de/vakuummotoren.htm

I am not trying to piddle on your parade, but having been through the learning curve, and come out of the other side as a winner, my twin cylinder even prompted Jan Ridders to have a go at making his own after I had shown him mine, this was when everyone thought a twin cylinder could never be got to work. Then everyone else started to persevere and got theirs going.

If I was you, I would get the plans for say the 'Poppin' (not one of Jan Ridders to begin with, very temperamental) and make it, just to see if you can get your tolerances and materials to work. Then when you have a LOT more understanding of the processes involved, go for it.

[ame]https://www.youtube.com/watch?v=IyrWRBoC-2c[/ame]


John

 

[Shipdisturber]

OK, well now I know the difference between a Flame Licker and Popper engine, I assumed those two engines were the same thing. The popper engine does look the most efficient by far by how it pulls the flame straight in with less turbulence and more heated air intake. A swirling motion of the intake air would assist in cooling on the power stroke and from what I see about the flame licker it has to be just right. Now I have some questions, will a longer stroke give you more torque or power at a reduced RPM and increase the efficiency of the power stroke? I realize that centrifugal force is greater on the outside perimeter of the flywheel and mounting the crank pin further from centre would rob some of that force. I would have to mount the crank pin further from centre to compensate for the longer stroke. If I increase the rotating mass of the flywheel that would help in the long run but would my motor produce the power needed to keep it rolling. As far as using the plans of others I never do that I find it quite boring to do that. I collect the information that I need from you guys and the rest I will figure out on my own like I have done on most of my projects. So far my hobby builds have been RC boats and helicopters. I have worked on diesel engines on a steady basis for the last thirty years so I am very familiar with with tolerances, lubrication, dirt, heat and parasitic load. These little engines are a challenge but one I'm sure I'll do well with them.