craft plane pulse jet

[Sebastian LFT]

Ed Bash's video inspired me to get back on my valved micro mini. http://www.youtube.com/watch?v=lfhgD9yTwEs It looks similar to the craft plane pulse jet plans listed here with about 155.9 grams of thrust. This thing just keeps going for over 3 minutes. I decided to put away the arduous task of developing a poppet style valve and go with an angled reed valve set up. Difficulties with reliabilities and task of making such a valve gets tiresome to say the least. Never count me out with coming back to it though. I did get some results to keep my interest in this tinkerers black hole. Anyway, here is my 1/3 set up for a craft plane style pulse jet. I removed the old head in favor of this one with the ability to make adjustments including adjustable tail end. I'm still waiting for my order of spring steel to arrive so .002" steel shim stock took one for the team and sacrificed itself for the good of micro propulsion. I'm hoping for at least 20 grams of trust. Weight is about 40.5 grams with sliding tube.

[Mark]

That was a good video of Ed Bash's plane. I don't think I've seen such a small pulsejet fly on a plane before. And I liked what he had to say, "THIS SMALL SIZE MAKES THE NOISE LEVEL ACCEPTABLE AT MOST CLUB FIELDS." Right there is a big plus. I suppose he is using methanol for fuel.
I once bought a Sibley-sized pulsejet on eBay and I must say that even though it only had a half inch exhaust tube, the sound was rather piercing and the backfiring even hard on your ears. So even at that small size, it's still a pulsejet. ha
But it's the kind of jet that you can work on in your garage and not upset the neighbors, which is nice. On the topic of your jet, you ought to be able to make a ton of reeds seeing as your valve is so small. I have some .002" inch blue tempered spring steel and I guess you know it's really bendy. ha
When I was making single petal reeds out of some .003" spring steel, I would use a fine point permanent marker/Sharpie and draw the shape on a piece of the spring steel. Then I would rough cut the petal with some scissors and then using my grinder, polish off the rough edges ever so carefully. Then I drilled a hole for mounting and mounted my petal valves to ordinary washers. It's sort of like you said, these little jets are kind of like a black hole adventure that you may or may not emerge from. The smallest I got to run was an 11 or 12 inch design. And it was more addicting than most anything to me for several months, staying up late at night doing test runs in my fireplace even. The instant on effect when I would start it just delighted me to no end, a screaming engine in the blink of an eye. And everything was so small and manageable, low cost parts, not a lot to lug around, etc.
Are you using acetylene or some gas of some sort for your 1/3 size model? I found that methanol in cool dry air is pretty forgiving. But it could very well be another black hole if you have gotten spoiled with acetylene. ha
Really glad to see your post. Very inspiring.

[Sebastian LFT]

Thanks Mark, I worked on it last night and just about had it sustaining. I did have the camera fixed on it but wouldn't you know...the batteries crapped out. I did try butane at one point. It sucked that down at an enormous rate. More to come...

[Sebastian LFT]

Well, I got it running The first time I had it going full blast the grub screw backed off and the intake plopped out. I can honestly say that the intake was a wee bit hot. Here is a second running...

[Mark]

Well, now what? ha
Acetylene is kind of hard to carry around for a plane or car weight-wise. Your engine is the smallest valved I think I have seen. It sure looks little next to your hands and fingers. What diameter is your exhaust tube? It's really tiny. I'd almost think it could be a little bit shorter because the exhaust tube looks so restrictive/narrow but I don't really know. The sound is intersting to listen to, does it have any characteristics that the mic didn't pick up? My little ~12 incher would start my fireplace frame and doorbell ringing sympathetically, you could hear a faint tone/ringing after the engine stopped. Of course even my dachshund can start my doorbell ringing, he has such a sharp bark too. Then too even a tuning fork would do the same I suppose.
I wonder if on such a small scale if something like a "snorkeler" (jam jar with exhaust tube), could cycle fast enough to compete with tiny pulsejet, if it could because of its small size breathe well enough from just one end to throw as much air? Even a small chamber will pop pretty loudly with acetylene and air confined in it.
Anyway, nice to see you alive in Black Hole Adventure Land. It's a unique field with patience more than a virtue.
Good work.

[Sebastian LFT]

Different tail configurations. I'll talk about it later when I get back home tonight...

[Sebastian LFT]

Anyway, when I figure out a way to fuel this tniy beasty(definately stuck in the Event Horizon), I have the perfect set up in mind for micro flight.http://www.microflight.com/Online-Catal ... rter-Set-1

2 pcs of 90mAh Bahoma Lipoly Cell

2 pcs of MiniAct 1.1g magnetic actuator with nanoconnectors to plug into receiver with ease

Micro9 3 Channel PlugnPlay 0.9g Receiver
• Approx 0.9 gram weight
• Outputs for single motor and 2 actuators, ideal for rudder and elevator control or V-tail elevon control
• Plug and Play nanoconnector sockets for your actuators and motors - no soldering needed
• 10mm Bahoma battery terminals for quick and easy battery connections
• LED and Audible Tones to indicate status and frequency number (6 frequencies)
• Built-In Low Voltage Cutoff protects your Lithium cells from over-discharge

all this for 100.00$