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TP180-18 starting to take shape!!

Posted: Sun Nov 05, 2006 5:22 am
by NickC
First off, to anyone wanting to build a pulsejet for the first time: get a set of trammel points (use them), and do not use a jig saw to cut it!!! (band saw or power shears would be best) I had trammel points, but no ruler to put them on, I ended up printing a big template and painted over it and cut out the un-painted part, don't be lazy like me!! Luckily, I have a friend with a pretty extensive shop and he was able to save it.

All the cones have been tacked together, it still has to be welded together and fitted though. I'll post some pictures soon. I think it'll turn out nice, TIGged stainless 304.

Eric, how close do I have to be on the measurements? I think I might end up a little short on the tailpipe length (1/4"), I'm using an extra 1/2" in the U-bend originally it was added to try and get a water injection system to keep making power (not blowing out the flame front).

re: TP180-18 starting to take shape!!

Posted: Sun Nov 05, 2006 5:51 am
by Eric
Well the closer the better but thats well within tollerances.

Eric

re: TP180-18 starting to take shape!!

Posted: Sun Nov 26, 2006 5:39 pm
by NickC
USPS SUCKS!!!!

Eric had made me an injector and now the great United States postal service has more than likely lost the package after 3 weeks and no signs of it....

re: TP180-18 starting to take shape!!

Posted: Wed Nov 29, 2006 9:30 pm
by NickC
shit...

what should I do for an injector? I guess I need to find some oilburner nozzles? I don't think I can afford to get a machinist to make me an injector. machinists want $60-$70 an hour and that injector would probably take 3-5hours.

i seriosuly fucking hate usps right now....

re: TP180-18 starting to take shape!!

Posted: Sun Dec 03, 2006 1:59 am
by NickC
Here are some pictures. I had a fabricator friend help me with it :D. I gave him the intake to flange and said cut it back after you flange it to get a good measurement. I guess he forgot so now the intake is a little over 11" inches. I made the tailpipe about 1" longer so that it would work well with water injection. If I run methanol it's already got a lot of oxygen in it so maybe limiting some of the air flow with a longer itnake might not be so bad and the intake air velocity might come up a little. i think a longer intake will move the window of combustion a bit closer to the intake? Anyhow, I'll adjust it later if it's a problem.
Image
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re: TP180-18 starting to take shape!!

Posted: Sun Dec 03, 2006 3:57 am
by Mike Everman
Ah, it's a beautiful motor!

re: TP180-18 starting to take shape!!

Posted: Sun Dec 03, 2006 4:58 am
by Eric
Great looking engine! Make sure to take some nice daytime pics, while its still perfectly shiny :)

I think I already told you about it in email, just in case I didnt, give the engine a bath before you run it, rub it down with cloth and dont touch it, and then use some sort of degreaser to get rid of the oil salts and finger prints and smudges before you run the engine. If you do this the engine wont oxidize on the surface where you touched it, and even if it turns brown, it should be a shiny brown.

The longer intake shouldnt much of a problem, the longer tailpipe will also help counteract the intake. Did you add the 1" to the expansion tube? In this case that would be the most useful place to add to.

A straight tube injector will work well to test it out, and a rosscojector will work well once you get it adjusted. Unfortunately I'm not going to be able to make a decent injector and get it down there in time to do any trials, my lathe is still being a pos with little pieces and I have so many other jobs right now.

You might want to make a few of larry's simplejectors and a few rosscojectors, they wouldnt be adjustable but they are cheap and easy enough to make that you could do a few and swap em.

Eric

re: TP180-18 starting to take shape!!

Posted: Wed Dec 06, 2006 5:14 am
by NickC
started on the stand tonight. The stationary part of it is almost done, i need to add feet (so i can stake it into the ground), a spring mount, and add a cover to the bearing tracts. The stand is setup so the jet is mounted to a rolling "chassis" which is connected to a spring and then i'll add a little meter so I tell how far the spring moved to measure thrust. This is the first time I've been able to put a big idea into reality, a few smaller ones like my pneumatic potato guns and pneumatic "pyroclastic" flow volcano (it owned the baking soda/vinegar ones) have been though. I think it's mainly the new welding capabilities :). welding is so useful!!! welding makes so many things possible. I've caught myself on fire twice in the past few hours, so I keep a fire extinguisher on hand. I was wearing some holey jeans with the threads kinda hanging off and they caught on fire. I need to wear some less flammable stuff lol.

re: TP180-18 starting to take shape!!

Posted: Wed Dec 06, 2006 9:38 pm
by thecheat
I agree, I've been on these forums for a while, and have never been able to build anything. The welder has FINALLY changed that, best purchase I've made! Besides it being really fun, the possiblilites are now a lot bigger.

Now if I only could get a mill and lathe...

It's very encouraging to put ideas to reality, whether they work well or not...

Anyways, I want to see this thing run, it's a real beauty! Perhaps you could add a seat and a steering wheel....

re: TP180-18 starting to take shape!!

Posted: Wed Dec 06, 2006 10:56 pm
by NickC
eventually it will be a seat and handles :lol:

I've got a pocketbike chassis, the one's with the real tiny wheels. It'll only be ridden in full leathers and race gear.

re: TP180-18 starting to take shape!!

Posted: Sun Dec 10, 2006 1:12 am
by NickC
It's DONE!!!!!


I haven't started it yet tho, low on propane and 20 degree temps dont mix well. I need to get a miter/chop saw, bad!! I cut all the metal with a damn jigsaw, and it's a fairly advanced frame.

re: TP180-18 starting to take shape!!

Posted: Sun Dec 10, 2006 10:06 pm
by NickC
not even a pop......

The spark system (old leafblower magneto, it was wobbly and really crappy) was too weak to drive a long plug and the short plug didn't get into the chamber very well and it was a weak spark.

My propane tank doesn't seem to flow very well either. i've got a rosscojector on the propane line.

re: TP180-18 starting to take shape!!

Posted: Mon Dec 11, 2006 1:32 am
by Eric
Hmmm. The faster the RPM on the drill that you use to drive it, the hotter the spark will be. Because the magneto is basically like a capacitor system it will lose the charge if its not spinning fast, the faster it spins the more juice you will get.

The normal 3/8" drills are pretty slow and dont drive my one magneto very fast, but the dewalt 3/8" drill spins like a maniac and can get 1/2" sparks no problem that will shock the crap out of you.

Also maybe spray a little wd40 into the cylinder to give it a little lubrication and a big boost, make sure you remove the spark plug so theres no compression :)

Connect the wires directly to the spark plug too, sometimes if you have the ground connected to the engine, your going to have a lot more resistance than right connected to the spark plug.

The spark plug hole on the TP-180 is the position that is the best for starting, but its also a very high pressure area when the engine is running, so using a torch to ignite it with the spark plug out will get the engine going on forced air, but you have to cover the hole because it will litterally leak pounds of thrust from the side and wont run very high or very stable.

If you open the rosscojector up a bit, with just a tap from a hammer you should get a lot more flow. Most of the guys have to have some comprimise between flow and self starting characteristics.

If you have a mapp gas torch that you can heat the combustion chamber with, it should be plenty hot to auto ignite the propane.

Eric

re: TP180-18 starting to take shape!!

Posted: Mon Dec 11, 2006 1:44 am
by NickC
so i don't even need a sparkplug? just get the chamber red hot with a torch, then turn the propane on and it starts? or will it need some forced air? The propane is only there for starting/warming purposes, right now I have an almost straight cut rosscojector (it's angled very slightly since it's offset and attached to the oilburner nozzle).

re: TP180-18 starting to take shape!!

Posted: Mon Dec 11, 2006 5:05 am
by Eric
You will need forced air but you can substitute a torch for the spark plug. What kind of spark plug did you use? If its something with a common thread that you can get a bolt for, you can drill a small 1/16" hole through the bolt that will still allow ignition but limit how much air can flow from the spark plug hole so it should fully run.

How long of an extension did you get?

Eric