3.7 Liter Pulsejet

[DR]

I got hooked on pulsejets, about a year ago and proceeded to build 5 of them, but stopped around August, of last year... Warm weather comin' aorund, the bug bit me, again.

I made a cheesy/generic webpage of the engine, showing most of the details. The webpage includes a couple of links to videos, which are posted on youtube.

<a href="http://sites.google.com/site/drspulsejets/" target="_blank">DR's Pulsejets</a>

As an aside, too bad (for me) that spudfiles doesn't have a pulse jet forum. These are relatively easy to design and build and are a lot of fun, to play with.

[chinnerz]

i was considering converting a bike to be propelled via pulse jet... gave up on it as the costs exceeded my budget by a fair amount.... ill see if i can find some of my old plans and post them up here

[ONEWING]

Nice running engine I made one many years ago, in fact while I was away at university I made the <a href="http://www.spudfiles.com/forums/brass-h ... l">harpoon gun</a> the first year and the pulsejet the second, something to fill in my time that judging by my grades would have been better spent studying.

Though unlike the gun this engine never worked! I got way ahead of myself building the trike before seeing if it even worked, it was designed to fit two of them. Though I never really tried to tweak it, the engine dimensions themselves should work as its based off the original lockwood hiller patent, thinking the fuel nozzel was at fault.

[inonickname]

Jesus, a 6" chamber..it must shake the ground..

I doubt I could ever run anything that would be so loud in town, though I may attempt a smaller one.

Edit: Finished, the chamber is 40mm (id), and the whole thing is around 30cm long. It's in a similar configuration to yours. It still needs a spark plug and a fuel setup.

[matti]

Hi DR, your not the only one hooked to pulsejets at spudfiles
here is my first pulsejet, its a valved one:
http://www.facebook.com/photo.php?pid=1 ... 1535067785

[DR]

chinerz:
Any plan sharing, would be greatly appreciated! - This is EXACTLY why, every time I've ever built anything, I've posted detailed plans on how to make it... at the very least, a detailed description.

Too many pulsejet designs floating around and people are unwilling to share them, as they expect to make money off all of their R&D. I was the person who designed the very first Hybrid cannon and posted specific details on how to build it, on the old SGTC Forums. Another forum member (luckythirteen13) and I perfected the first cloud-style BBMG... and posted detailed plans.

Geez; semi-auto and full-auto golfball cannons, basketball cannons, full-auto tennis ball cannons... If I had been stingy with those designs, I guess I could have been a millionaire, by now?! - Yeah... right!

This could be (as I've already implied) a great new forum. They look a lot like spudguns... they run on propane... they're loud... yeah, it'd rock!

Kickin' ideas around and posting stuff, so your forum buddies can go ooh...ahhh! That's what these forums are all about.

Thanks, for your reply.

ONEWING:
That's an AWESOME-looking trike design! Too bad those components weren't sitting in my garage, as I'd have it screaming down the street, by tomorrow!- Ha!

I've seen a LOT of videos on youtube, with people having a LOT of problems, getting their lockwood-hiller to start... It's ALL in the injector, as you've implied.

inicknoname:
You don't mess around, do you? I'll be watching this thread, to see if you get yours running!

matti:
That's a beatiful valved-pulsejet! Did you make it yourself, or purchase it from someone/somewhere else? I've been wanting to make a valved pulsejet, but have no access to machining equipment...and valveless are cheaper and easier to fabricate!

Thanks, to all, for your replies.
~Dave.

EDIT: Edited for multipull grammatikal airorrs

[inonickname]

Too many pulsejet designs floating around and people are unwilling to share them, as they expect to make money off all of their R&D.

Agreed- hoarding pulsejet designs in the interest of making profit could almost be considered an oxymoron. By nature, pulsejets are terribly inefficient and there will (touch-wood) always be a better engine for the task. Granted, some will sell as a novelty to people with money to burn- but hiding the plans for this purpose is pointless. Valveless jets are so inanely simple in construction that the average DIYer could improvise one (assuming they have the basic tools).

Well, I got my camera out and snapped some photos of my jet. Granted, it's absolutely tiny next to yours and will be tricky to get working- but should be a fun novelty. I used (copied) your design- it seemed like a good one to execute on a smaller scale where making a bend for a Lockwood-Hiller design would be difficult.

It needs some cleaning (probably a quick dunk in a bath of HCl) and the sparkplug added..but it's essentially done. By the way, the front looks weird because it's made of checker-plate.




Oh, and...


Initial plans are to get it running on propane- though it would be excellent to get it to run on liquid fuel. Assumedly that will be substantially more difficult than even getting it to work on propane- but we'll see.

Thanks for sharing your design/experiments DR

If you need something machined I'll do it for the price of postage (as long as I have the stock to begin with)- though I don't think we live awfully close to each other. So perhaps smaller parts would be better, unless you're willing to pay a little in postage.

Edit: Wow, I expected to have a massive fight to get the sparkplug in the chamber..I was thinking I would have to go to the extreme of welding it in there or something. Turns out I can just run an M14x1.5 die over them. This cuts the threads a little differently, but results in only very slight thread loss. With a washer it should still seal fine.

[DR]

inicknoname,

Thanks for the machining offer... I may just take you up on that... have an idea for an injector design.

If you don't mind, would you post the dimensions of your pulsejet... and try to be as accurate as possible (i.d. / o.d. and all parts included)

[245Tommy]

I made one out mild steel, the chamber started collapsing but it still works. I measured 3lbs of thrust.

[DR]

245 Tommy,

I made one similar to yours, with a piece of 3" Exhaust Tubing. The intake tubes are 1/2" EMT, and the Tailpipe is 1" EMT.

The front and rear of the combustion chamber is dome-shaped, as I used two stainless steel soup ladles, for the parts.

<a href="" target="_blank">Homemade small Thermojet</a>

...There's a tutorial, at the end of the video.

[inonickname]

inicknoname,

Thanks for the machining offer... I may just take you up on that... have an idea for an injector design.

If you don't mind, would you post the dimensions of your pulsejet... and try to be as accurate as possible (i.d. / o.d. and all parts included)

Alright Just send me the drawings and I'll let you know what I can do.

I'll go measure it with some calipers now.

Edit: Cross out "now" and replace with "soon". Parents are dragging me into some Easter stuff..

Hmm, I just watched your video on the pulsejet (with tutorial). The shape reminds me very much so of a propane cylinder. Given that you can get them in various sizes (up to very bloody large) they could work quite well instead of manufacturing a chamber from scratch. Anyway, get back to me on those things you needed made

[matti]

matti:
That's a beatiful valved-pulsejet! Did you make it yourself, or purchase it from someone/somewhere else? I've been wanting to make a valved pulsejet, but have no access to machining equipment...and valveless are cheaper and easier to fabricate!

Thanks DR ! that pulsejet is fully made and designed by me.
I made it at school where i was studying machining..
I have some plans for that if you want.. mostly cad drawings, but i have never tested that pulsejet so plans are not very reliable
now I got my propane tank and fittings.. just waiting for summer, Its cold here in Finland now

Good to see you are still building stuff and pulsejets are lot of fun.. i remember you very well from studtech times !