jim's poppin engine video!!!!!

[jim]

well it runs!!!

its in a vice due to a miscalculation on the frame for it!!

also the valve spring is an elastic band, the proper spring just wouldn't work!!

i've got to say for my first poppin engine i'm pleased behond all my expectiations!!!!!!!!!!!!

enjoy!

[chuck foster]

WAY TO GO JIM
chuck

[Brass_Machine]

Awesome!!

Nice to see an engine run that YOU built eh?

Eric

[madjackghengis]

Jim, if there was ever a moment when I thought I could get through life without building one of those, your video just killed it dead, and I will build one if it is the last thing I do, just to give to my mom.  That is simply awesome and what every real man wants!!!! mad jack

[Stilldrillin]

I couldn`t watch your vid at the time, due to computer/ operator problems....... 


It was well worth waiting for Jim! 

What a little cracker! 

Well done......   

David D

[NickG]

Jim,

Not been on here much lately so missed this - well done that is fantastic!!!     

It might just be the inspiration I need to get back onto mine. It all went pear shaped when my vice broke and I was too stubborn to just buy a new one, then I couldn't make the acme thread so needed to make a boring  / threading tool! things just got out of control then I couldn't be bothered for a bit and other stuff started getting in way.

Hopefully I'm going to try and get back on it next week

Nick

[jim]

i've not been in the shed much lately, but needing inspiration i got the poppin engine running today.

due to the lack of an oil cup, i've been giving it a squirt with WD40 to keep it lubed, between runs.

had it running for about ten minutes, i was playing around with the flame position, got it running really well!!!

i then had the non too bright idea of squirting WD40 in the bore to keep it lubed, now most people would say that is bad idea (WD40 being quite flamable), the penny dropped as soon as the the fire ball appeared!!!! flames were everywhere!!!!!
 

lucky for me, i had my safety glasses on (that saved most of my eyebrows)

[madjackghengis]

Hi Jim, I've watched your video, several other videos, and having searched my shop, accidentally found a "flame sucker" I built perhaps twenty years ago, a Phillip Duclos design from Home Shop Machinist.  I have worked on this one on and off since it was "finished", and have yet to get it to even get an extra half a turn.

sitting in my computer room

looking at the crank and cam

sitting on the work table in my shop.
I've made a new piston that fits tighter without sticking, done everything I can think of to alter the timing, and changed fuels, and am about ready to make a new cylinder and piston, but I can't make up my mind if it's worth trying, or a waste of time.
I got a copy of the PDF file for building the "poppin'" from someone, but it got lost when my computer went down.  I was wondering if you had a copy and could share it.  I'd appreciate it if you did.  By the way, did you ever get a proper base and lamp for this engine, so it could sit on a table or the like?  It sounds great running in the vise like that.  mad jack

[jim]

i'll sort a copy out

i found all my problems were the valve not sealing.

i had it running from a cold start the other day. i just make up a new valve when i fancy running it!!!


and, i think you'll know the answer to the base question!!  i've still not got round to it!!!

[madjackghengis]

I tell you Jim, I fully understand!  I've got this one so it spins freely with a very nice farting sound if turned fairly slowly, it sucks in the flame, and it gives a resounding "pop", if you just flip the flywheel enough to just inhale the flame, and get it past the compression, I've moved the flame all around, moved the valve up and down, pre-heated it, spun it over cold, even taken off the valve and smoked up the running path of it for lubrication, and it sounds closer to working now than it ever did but it still does nothing to get past my finger power.  From what I've seen, the most formidable ones are all "poppin's", they are the only ones I've seen actual videos of them running, although someone did make a model like the one I made, but half the scale, with a quarter inch bore and said it ran like a champ.  I've got a steam engine started, a Stirling engine half completed, the radial engine half done, and they are all on the side waiting for me to get tired of fooling with this one.  At least I'm not bored. mad jack

[mklotz]

I've built both Poppin and that engine...



My Poppin is a much better runner.  To get the Duclos engine to run, I have to preheat the cylinder quite a bit and then apply some heavyish oil to the piston to enhance the seal.

However, once started, the thing runs like a banshee - so fast, in fact, that I have difficulty understanding how the hot gas can quench as fast as it apparently does.

Keep at it.  The design is solid but the engine is tempermental at best.

[madjackghengis]

Hi Marv, thanks for chiming in on this, I appreciate it.  I've been studying my non-runner, and the design in the magazine, and I think I've found the original problem.  I didn't have or use a milling machine for the cam, but set the blank off in a four jaw, expecting it to come out the same.  I could tell right away from the looks of my cam, and that in the picture things didn't turn out the same.  It took a couple of hours, but I figured out I'd have to offset the blank a whole lot different to get the same cam configuration.  In the end, my timing is off on both opening and closing.  I have to either use the rotary table as is shown, or calculate the offset from the figures given.
    I can see by the looks of your engine, it's a runner, and I think I've got the knowledge I need to make mine run, but you're statement regarding "poppin'" has me set on building it, even if I get this one running.  Too many engines, not enough time.  Thanks for showing that one of these will run, Phil did say his was turning about three thousand rpm when up to speed.  Funny you should have to use oil to seal the piston when he cautions against getting any oil in at all, on account of getting the piston gummy.  I reckon I can get this cam thing straightened out this afternoon, after everything else is done.  Again, thanks much for showing your engine, it adds some confidence after a lot of years spent staring at the thing.  mad jack

[madjackghengis]

At the risk of taking over Jim's log, I think I found the problem with my flame sucker!  After studying the build in the magazine, and studying all my parts laid out on the bench, I found my cam just doesn't have the same profile as the one in the plans.  I used a different method of generating it, as I didn't have a mill at the time, so I used a four jaw chuck, and used Mr. Duclos' figures for my offset.  I did it again, and came out with the same shape and form of cam profile, the wrong one.  There is a difference between milling the cam on a rotary table after offsetting it, and offsetting it in a four jaw chuck and turning it, with the four jaw chuck you have to use the diameter of the cut for the offset, rather than the radius, so I set up the four jaw with a fresh piece of aluminum, and did it again, using new numbers this time.

Note the substantial difference in the cam curves from the old on the left, to the new on the right.  I think I will finally get this old project actually running, once that cam and crank are finished and put in place.  If so, I will finally get the only engine I ever didn't get running, operational and finally close that book after giving it to some worthy soul I hardly see, so I won't be haunted by it any more. mad jack