Jims Little 3 Lb Thermojet

[GRIM]

Hey mr irvine thanks for the help
correct on two counts

I cut the inlets down about 3/4 inch and fitted two thin sliding flared tubes inside , that pointed me in the right direction , power has gone up ,

last (very short) run, no sliding inserts, deep double d, vapour fueling @ 80 psi static , i got about 5 lb before it flamed out

a couple of observations ,

the weather is warming up here my static gas pressure has risen from about 45 psi to nearly 85

with the injectors deep , this little sucker allways starts
"the first time" just sparks on, open gas valve and away she goes,

the second and subsequent starts allways need air blown in the inlets wether the cc is hot or cold

i think i have discovered why ;

if i drain the gas hose and injectors etc of gas by blowing in the cylinder end of the hose ,

then connect to the cylinder , sparks on , open gas valve, away she goes

i believe the gas is pushing air ahead of it , the air is coming out of the injectors soon to be followed by gas, producing a rapid ramp up of mixture from too lean to burn and right thru the stoichiometric range
causing the initial BANG that sets these devices in motion

i believe Mr Reynst wrote somewhere about the initial bang thing

anyway i have still got a long way to go before the undercarriage on this one will get a set of matching wings ,
but at least im headed in the right direction again

thanks

[Irvine.J]

Glad to be of assistance Grim-man, I'm glad it worked well! Keep us informed of how your going, it is a very different engine and I'm interested to see your results.
Be well!
James.

[metiz]

Here's my thermo. It looks a bit "rough" *kuch* but that's because this is my first welding project. It's made from plain steel And looks like a battlefield, but who cares:P

it's based on the 3lb thermo but with larger intakes because the pipe I used was thicker - about 11 cm instead of 7 something. Have not ran it yet, but I will by tomorrow. Pretty shure it still has a bunch of leaks but we'll see.

I've got 2 much better engines still in the make - one big ass lockwood and one bigger-ass Irvine powered surprise :D

[Irvine.J]

Lol metiz that looks great, can we speak tonight? I've been meaning to ask about how that welding wire went. Good stuff man!

[metiz]

ok I just tried it but I can't get it to sustain. some mighty bangs, a couple of forced air runs - one so hard that it almost took out the stand (kekekeke!) but that's it. I've fixed a couple of leaks while we were at it and that did improve it a bit. Pretty sure that 99.9% of the leaks are gone now.

I think it has something to do with my "ignition" wich consist of throwing a sparkler down the exhaust in the CC. Needless to say I need a ignition system fast.

Can anyone help me with that? maybe a simple schematic with all the parts I need? I am looking for something that will spark 10/20 times a second but how that is achieved I don't care - a lego motor with a piece of aluminum foil wrapped around it wich makes contact with the circuit every 180 degrees or something

Finally, I have had to make some modifications to the intakes because they had a bigger diameter as proposed in the plans

the dims are 1.8cm diameter an 11 cm long
the Rocojectors I use are 6mm thick and are very thinly pinched

Hope this is enough info to get some advice

Cheers

[Jutte]

Hi Metiz,
What I do before I put the spark plugs on a couple of the ones I built is this.Turn on air and gas - medium low air and a good bit of gas - light the tail pipe with a bic lighter - be careful as a lot of flames should come out.Back off the gas until the flames get 'rocket like' and blue in colour.Now by increasing or decreasing the air and gas you should be able to get the flame to advance down the tail pipe - making alsorts of weird noises -or the flame will get stuck and 'blossom' on the end of the tail pipe and a start to high pitch howl.Anyway by adjusting the air and gas you should be able to get the flame to go down the pipe and into the combustion chamber(small adjustments).What might happen then is you will get the flame front to go in the CC and stay there - it still won't pulsate but will heat the CC up.Let it heat up a bit then start increasing the air slowly - it should start thinking about going into pulse jet mode - the noise will go up like nothing you have experienced if it does ( heh heh ).Lots of juggling and the use of a bic lighter - but it has worked for me(my lighter is empty it just makes sparks).
The bangs you are getting are probably from too much air - but man are they fun or what!
Hope this helps - there are a few diagrams of spark units on the forum.

[Irvine.J]

Metiz, these are the guys and the brand of the SS mig wire I use before tigging, works just fine without gas.
Goodluck buddy, there does look like quite a bit of oxidasation there...
http://www.cigweld.com.au/uplFiles/product/CIGWE212.pdf
http://www.cigweld.com.au/evolution/pdtCatalog2.asp
And click Autocraft 316LSi

Get yourself a wire brush to scrape off the flux cheif. Should look pretty as a picture when done, and yes they have it in 5 kg, .9mm, though I use .8.
http://www.cigweld.com.au

I'd suggest drop em an email, tell them where you live and which reel you want of the 316Lsi, (probably start with the 1kg spool and get yourself a .8mm tip from any welding shop) and ask them where the best place to buy it is, if they stock anywhere in europe etc. If not, I'll link you to some dudes here who can send it over for you. Peace.
Write to them here :http://www.cigweld.com.au/contactUs.asp?div=cig

[Jutte]

Hi Metiz,
Sorry I forgot to say that once the flame front is in the CC - I usually also move the fuel line in or out searching for the 'magic spot'.
It all sounds very complicated but it is really quite easy.
Still with a spark plug in it is even easier - good luck!

[metiz]

Thanks for all the help guys!

I just opend up the Roscojectors a bit and the results are quite noticable so-

I'm proud to anounce it runs!- and fucking how! this thing goes from zero to awsome in no time flat :D it throttles like mad and there's a one foot flame from the exhuast! - and 2 10cm ones from the intakes!

Oh man adrenaline rush :P
2 video's below made with a camera phone. I'll try to get something better up soon

(oh yeah - the 2nd video is from behind a window :P)

[Eric]

Awesome job. If you point it straight up in the air it should be a lot quieter since most of the sound will go up and not be reflecting off peoples houses.

Kind of like firing a gun while out on the ocean, theres nothing for the sound to reflect off of and you just kind of hear POOF.

Eric

[metiz]

hmm augmenter time

[Irvine.J]

WAAAAAAAAAHHHHHHHHHHHHOOOOOOOOOOO!!!!!!!!!!!!!!!!

[Jutte]

You beauty! Awesome ! YEAH!!!

[metiz]

WAAAAAAAAAHHHHHHHHHHHHOOOOOOOOOOO!!!!!!!!!!!!!!!!

More like ROOOOOOOOOOOOAAAAAAAAAAAAAAAAAAAAAAAÁÁR!!!!!!!!!!!!!!!!
:P

[metiz]

Augmented :)

and tested in the field - runs like teh shits. my sister could hear the thing go from 1 km away - from the bottom of a small slope :D