pulse jet ignition

M

Machi san

Morning gents. Me and my dad are building some pulse jet engines because we both wanted a cheap exciting hobby that gives us a break from cars and tractors.

Here is the ignition system that we have made. Iam waiting for stainless sheet. stainless mig wire and gas.

Eventually we may end up with a pulse jet hovercraft but I gotta learn how they work properly first :)

Now I fully understand there are probably many easier options that I could choose, but being from an automotive background I decided too use a points ignition distributor, ballast resistor and coil. This is all powered by a battery drill. I think ill swap the drill for an electric screwdriver! The screwdriver runs at 140rpm which should give me 8ish sparks per second.

Is 8 sparks per second adequate?

It's still in mock up mode at the mo, mostly bodged for testing!

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https://www.youtube.com/watch?v=Tc_HYWc8fZA&feature=youtube_gdata_player

That isn't flat out in the video and I would expect a healthier spark once the wiring is completed properly.

I have also had a go at triangle injectors like grims thread, look pretty good but no pics.
 
Awesome.

That spark box looks good, and if the pulse jet [pun intended]never gets of the ground[/pun intended] then you can always use it in a flamethrower exhaust.

Butane/Propane mix for fuel?

I've wanted to have a go at building one of these for ages - I even got as far as doing the calculation for the net of the cones to fab the combustion chamber and exhaust.

I believe that standing well back and wearing ear defenders are good peices of advice :laugh:
 
8 sparks a second will be fine, you might even get away 4 or 5 a second.

the real challenge with a pulse jet will be the shape and length of the pipework, if you don't get it right, it wont run.

as for a hovercraft, that will be interesting, i don't think it would work if you are taking the lift from the jet itself, you only need a small amount of air after the pressure is built up
 
markbognor said:
Awesome.

That spark box looks good, and if the pulse jet [pun intended]never gets of the ground[/pun intended] then you can always use it in a flamethrower exhaust.

Butane/Propane mix for fuel?

I've wanted to have a go at building one of these for ages - I even got as far as doing the calculation for the net of the cones to fab the combustion chamber and exhaust.

I believe that standing well back and wearing ear defenders are good peices of advice :laugh:
Click to expand...

Msc pun of the week :d

Glad you like mate and flamethrower! fantastic idea (Y) some kids built one on junk men and it looked like fun :D

Tbh there is no reason that I can't use the spark box for a multiple of diferent apps. I also have a turbojet engine in the pipeline.

Ear plugs and ear muffs are a must and apparently the pulses can give you motion sickness Haha upto 200 pulses per second

NeX said:
8 sparks a second will be fine, you might even get away 4 or 5 a second.

the real challenge with a pulse jet will be the shape and length of the pipework, if you don't get it right, it wont run.

as for a hovercraft, that will be interesting, i don't think it would work if you are taking the lift from the jet itself, you only need a small amount of air after the pressure is built up
Click to expand...

Don't worry man I have managed to find loads of plans ranging from baby 3lb thrust upto bigger 40lb jets. Iam starting out with a 12lb Chinese style jet. If anyone wants plans or links I can add them on here ;)

Cool Iam glad my spark box should work! I'll be using cm-6 rc spark plugs

I think my dad is thinking about buying a hovercraft kit. I would use a motor or leaf blower for lift and pulse jet for propulsion (Y)

Cheers chaps
 
Yes Mark too begin with Iam building valveless pulse jets like these

file-20.jpeg


The lookwood style is the big 180 trumpet style that they had on scrapheap challenge and junk men :)

There are literally tons of valveless designs out there.

Jam jars and snorkels are hella cool ;)

I have some valved pj plans as well :D
 
Machi san said:
Msc pun of the week :d

Glad you like mate and flamethrower! fantastic idea (Y) some kids built one on junk men and it looked like fun :D

Tbh there is no reason that I can't use the spark box for a multiple of diferent apps. I also have a turbojet engine in the pipeline.

Ear plugs and ear muffs are a must and apparently the pulses can give you motion sickness Haha upto 200 pulses per second



Don't worry man I have managed to find loads of plans ranging from baby 3lb thrust upto bigger 40lb jets. Iam starting out with a 12lb Chinese style jet. If anyone wants plans or links I can add them on here ;)

Cool Iam glad my spark box should work! I'll be using cm-6 rc spark plugs

I think my dad is thinking about buying a hovercraft kit. I would use a motor or leaf blower for lift and pulse jet for propulsion (Y)

Cheers chaps
Click to expand...

to be honest if you can build a pulse jet then a hovercraft would be no problem at all, i built a hovercraft when i was 12 out of an old inner tube and a lawnmower engine. it wasn't perfect but it hovered,
 
to save the drill (cordless screwdriver) and dizzy, id use a ignition power transistor as found on almost every petrol car after 1992 and before coil packs bacame the rage, the k10 super s had them, then just knock up a 555 timer circuit, (i believe maplin do i kit) then you can pulse it however many times you want and have less bulk etc.
 
markbognor said:
Yeah, it just seemed to me that the horse shoe ahped type would be the easiest build. I found the website with the info that I was going to use.

http://home.no/andreas.sunnhordvik/English/mechanical/valveless_e.htm
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Thanks for the link Mark ill look at that later today :)

I was told that the lockwood is a fantastic design. Makes good power. but newbies should get experience with easier stuff first

NeX said:
to be honest if you can build a pulse jet then a hovercraft would be no problem at all, i built a hovercraft when i was 12 out of an old inner tube and a lawnmower engine. it wasn't perfect but it hovered,
Click to expand...

Ace. I'll try getting my jet to run and sustain itself first.

My dad has wanted to build a kitcar for years and now I think he would rather get a hovercraft kit :D would be awesome!

superls said:
to save the drill (cordless screwdriver) and dizzy, id use a ignition power transistor as found on almost every petrol car after 1992 and before coil packs bacame the rage, the k10 super s had them, then just knock up a 555 timer circuit, (i believe maplin do i kit) then you can pulse it however many times you want and have less bulk etc.
Click to expand...

Lol I wad with you up to power transistor then you lost me Haha. Electrics aren't my strong point but I'd like to make a neater setup :)

This evening I raided the scrap pile and knocked up this pj, my first lol

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It loosely follows pyrojoe's recipe from the pulse jet forum

Exhaust is 1 caliber 56mm x 20 cal
Inlet is .85 cal x 2.65 cal with flare
CC is 3.2 cal x. 3.2 cal

No fuel system yet but hopefully ill have something rigged up by tomorrow evening. I'll use a grim spec triangle injector to begin with and ill use propane :)

Id love to eventually run pjs on diesel!

Can I use combustion chamber pressure to pressurize a full tank? I'll go search :)

Wish me luck with running the beast!
 
Karl Iam skint these days and need a cheaper hobby. Drifting is simply too expensive so I have knocked it on the head :( gotta break my s13 soon :(

The reason I got into pulse jets was because i want to build a turbo jet engine, whilst researching i found so much info for pj that I decided to do that as well.

Turbo jet is kinda underway also. Just collecting parts at this stage :)
 
kev that is awesome im sure you will do a wicked job of it with skills like yours mate what sort of thrust will it produce?. are you defo breaking the s13? seems a shame bud. if you would sell it as whole fire me a pm when you want to sell if you want cause me and my mate are looking for a summer hobbie as there is nothing to do round here really lol.
 
Sweet Ed that's awesome thanks for that link (Y)

Scott as you say that's a bargain, but thanks for the offer anyways (Y)

Thanks Steve (Y) ill let you know but I think ill need some bits to finish my skyline. I want the liner as my everyday car cose it'll be quite practical.
 
Well guys, I have an update!

MY FIRST PJ RUNS :D

https://www.youtube.com/watch?v=HMY4vFh_2tg&feature=youtube_gdata_player

Observations from just over a minute of running. It warms up nice, it self starts with no compressed air. It sounds fantastic. Needs more fuel (its flatout in the vid, blue flames protruding long way out of inlet. It's running roscojector.

Tomorrow Iam testing on liquid propane. And ill change the exhaust slightly.

Also ill be making another pj and maybe s snorkler :)


Does mean I should start on a hover craft :D
 
Thanks Mark, glad you like it :D

I just bought the fuel lines I need for some full throttle runs. Max I could run was 30psi, now I can run 150psi :D
 
That was bottle wide open with no regulators. So what ever the bottle is supplying! I think I need to get a bigger bottle and make some mods to the pulsejet and I will also gain improvements with a better injector setup.

I think its time too make a new one :)
 
This is also made from random ugly scrap out of the skip at work :)

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The jet was just a quick hash up to get some kind of combustion.

Tomorrow we will try harder :)
 
here is my little rat jet, havent managed to get it too run yet :( it fired up on compressed air but wont sustain on its own :(
http://www.youtube.com/watch?v=yb5lyOREVno

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i made this crazy injector and hoipefully itll do the job tonight
http://www.youtube.com/watch?v=Nk4K0ugF3wk

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This week i have also been playing with jam jar reynst combustors
http://www.youtube.com/watch?v=dV-FQ_xLdCo

http://www.youtube.com/watch?v=RbgEb0zc39Q

this jam jar goes quite well and has an adjustable inlet port that kinda bleeds alittle air, probably work just the same without it though
http://www.youtube.com/watch?v=DQaqGxdoGJE
 
then last night i knocked up this little beast using a Matt black paint can and some pipe i had laying around. it runs on methylated spirits and i have also added some other things in like oil, paint and glue. the other fuels work awesome and make lots more power but its gotta get hot before it starts so meth/oil mix ftw.

here its is, his name is Mathew and he has a brother called Rex! He will be finished tonight
http://www.youtube.com/watch?v=ypH1VfNYlrQ

please excuse my bad language amnd stupid laugh :wasntme::blush:
 
tell that lil rat to fix up or i'll be sending 2 cats your way
lets get someone to sit on it to provide the air compresion and send him up to moon
i seen the big ones once on some show. what type of thrust gets going on these once up and running ?
 

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