Easy and possibly dangerious Pluse jet to build.

[sidecar_jon]

http://www.imakethings.com/2007/07/...rthday-make-a-jam-jar-jet-make-video-podcast/

It hadn't occurred to me til i was "Scrap heap challenge" that a "pulse jet" was just a tube that ignited a gas fuel and only allowed it to explode out in one direction. This jam jar jet even sounds like a doodle bug!

 

[ronm]

A "common sense challenged" friend of mine built one of those once-he took the gas tank out of his pickup, drained it, flushed it out w/water, then proceeded to try to solder up a hole...it went "pop-suck, pop-suck" all the way across his yard before it "ran out of fuel"... :shock: I told him he was luckier than he deserved...

 

[sidecar_jon]

hum the meths i have doesn't seem volatile enough or i have to play with the jar top hole, i got a few Woomphs...but no continued combustion.

 

[Bogstandard]

Hi Jon,

If you really want to do damage to yourself, try here.

http://www.beck-technologies.com/freeplans.html

You can blow yourself up in style :twisted:

John

 

[sidecar_jon]

i think that's a bit advanced seeing as i've only got a jam jar to go phuuut so far....

 

[Bogstandard]

The only problem with this type of pulse jet is the reliability issue.
The petals on the valves break up very quickly because of the fantastic vibration rate, so a continuous supply has to be made to keep the engines running. That is why they are going over to the valveless design, no moving parts at all, the only probs are that at the moment they don't have quite the same power output and some of them look downright ugly.

John

 

[sidecar_jon]

The only problem with this type of pulse jet is the reliability issue.
The petals on the valves break up very quickly because of the fantastic vibration rate, so a continuous supply has to be made to keep the engines running. That is why they are going over to the valveless design, no moving parts at all, the only probs are that at the moment they don't have quite the same power output and some of them look downright ugly.

John

From looking at clips of V1's they seem to have a shutter type arangement
as a valve.... but then longevity wasn't part of the design plan was it!

 

[tattoomike68]

I thought the V1's had a petal valve style. Im just a kid when it comes to that. I dont know.

 

[sidecar_jon]

After some research it seem my problem as ever is inaccuracy, the hole should be 11 to 12 mm... not as i had 15mm then after deciding it was too big probably nearer 3mm... but i've now run out of jars, so tomorrow the wife might have to eat marmalade all day.

 

[sidecar_jon]

I got it started!... and in front of a friend who's a research chemist too, he was suitably impressed, even if he did stand quite far off! I think my main problem was i was using a honey jar which was on the small side and too much Meths (you want fumes not liquid) Also the hole must be 12 mm. I found that once it failed t light, you had to open the jar and blow away the smoke to have any chance of it lighting again.