Flame eater no plans

[Fingers]

Hi everybody
I started on a flame eater I am building ,This project started when i found a nice piece of stainless hex
which I wanted to mount at 45 degrees to look some way like a cannon......I am using a CI piston 26mm with a 40 mm total stroke ,The crankshaft is built up,

I will silver solder this later just pressed together for the moment, and my flywheels need spokes or holes to lighten,
I have not figured out where or what type of valve to use yet, I am slowly running out of space but I will figure it out. Any ideas would be great.
Regards Jamie

 

[lazylathe]

Looks good so far!!

Have a look at these plans which Jan Ridders has made freely available on certain websites.
You are going to need to mill away part of the cylinder for the valve.

http://www.projectsinmetal.com/free...the-flame-eater-vacuum-engine-by-jan-ridders/

Good luck!

Andrew

 

[NickG]

Nice work Fingers - haven't you built a couple of flame eaters before?

I would use a reed type valve (very thin spring steel from a feeler gauge) as on 'Poppin' acutated by a cam, the cam is configured so that it forcibly shuts the valve at the right time - it will open pretty much when it's good and ready to with that sort of arrangement.

You will need another couple of bearing standing out of your base or maybe in your cylinder support legs for the valve shaft to pivot in then a cam follower (roller) and arm.


Nice work
:bow:
Nick

 

[Stan]

You might find a very short run time because SS has very poor heat conduction and the cylinder may quickly reach an equlibrium.

 

[Fingers]

Thanks Lads ,Nick you are right I have built one before it was, as recommended by Andrew, a Jan Ridders vertical flame eater with external valve. I would like to try a different valve set up this time.
Nick I wonder would I be able to use a similar setup to the poppin or will I have to make it side entry which I would rather not if it can be helped.
If anyone could help me out with a picture of the poppin valve setup this would be grate. I have seen a few videos of them running but no close up of the valve to get an idea from.
Jamie

 

[Fingers]

Thanks stan very true, The cylinder I am using is very slightly magnetic and dull compared to other stainless which I have seen. l am not sure what it is for sure but will carry on. If I get it to run once that will be mission accomplished, It will probably end up on a shelf after that anyway.
Jamie

 

[GailInNM]

Here are a few photos of the Poppin valve that might help.
http://www.homemodelenginemachinist.com/index.php?topic=1990.msg16055#msg16055
http://i801.photobucket.com/albums/yy292/kcmillin/CIMG1138.jpg
http://www.homemodelenginemachinist.com/index.php?topic=4556.0

Gail in NM

 

[NickG]

Gail beat me to it!

Good point about the material choice Stan, however, it's not as critical as for say a stirling. The hot gases that are drawn into the cylinder will always be a lot hotter than the cylinder itself so they should still contract. Curious engine the flame eater - it took me quite a while to understand what is actually happening!

Nick

 

[Stan]

Some of the members here have built flame eaters that will run for ever. I have not been that successful. With finned aluminum cylinder and head and aluminum piston mine always start to slow down as the cylinder temperature rises and eventually stop.

Mine were both made from plans and maybe deeper fins (thinner cylinder wall) would improve them but when you have a flame eater running, you are reluctant to change it.

 

[NickG]

Stan,

I think using an aluminium piston is making things more difficult for flame eaters. Friction and seal is so critical that the cylinder and piston material should ideally be the same material, or at least have similar rates of expansion. I wonder if your piston is expanding faster than the cylinder and the friction is increasing to the point where it stops?

That said, I've had good results in my poppin with a graphite piston - great from a low friction point of view and easy to get a good fit which means instant starting. However, I'm not sure that the cylinder might expand more and gradually reduce the good seal on mine.

The guy that designed poppin (and he had designed and made many successful flame eaters) intended it to be a cast iron cylinder and piston with a lubricator which constantly dripped oil at a controlled rate onto the piston. A thin motor oil is ideal as it can withstand the high temperatures and prevents the combustion products from adhering to piston and bore - which is one of the other main problems in having a sustained run with these engines. The only issue with the oil is that until it is up to temperature it causes drag.

I dont think cooling is the main issue here but I could be wrong, it will obviously help especially if a very long run is intended which is why some have water hoppers or cooling fans. Guess it all depends how long you really want to run it for.

Nick