www.pulse-jets.com

Steve, would you confirm the tentative engine total length, and the total length of the intake tube with the flare on it? I think this is going to be an SOB to get going--the intake length is very critical to successful operation.

yes, I anticipated that. I plan on making the intake length adjustable using the same method I used for the tailpipe of my first valved engine. It should be easy to get a good seal since I turned the 1/2" conduit on the lathe to make it perfectly round (and to get the galvinization off)

Larry, if you thought that was funny, you should have seen me yesterday when my shirt caught on fire while I was welding!

steve wrote:Larry, if you thought that was funny, you should have seen me yesterday when my shirt caught on fire while I was welding!

Happened to me at the age of about 20, working on interior mods to my friend's 57 Chevy [he wanted the outside to remain perfectly stock, but the interior highly customized] - his dad gave me a nice dress shirt as compensation for my klutzy effort at arc welding. Should have stuck with my tanks 'n' torch. Later that day, my dad said it had happened to him at work, once or twice.

Am important lesson, there: Don't go out for welding wearing your favorite Hawaiian polyester print ...

L Cottrill

Larry Cottrill wrote: For anyone who hasn't seen it before: That is a barrel of water [NOT fuel !!!] - the experiment was to show that a valveless pulsejet could be totally submerged and flooded with water, pulled up out of the bath and immediately started and run within seconds of the water draining out. (Certainly an important consideration in its favor ;-)

L Cottrill

There's our tax dollars at work. Research in Vertical takeoff submarines!

I really should of read this thread earlier. That linear lockwood FWE is almost exactly the same as my linear lockwood dynajet mod. Congrats on getting it running. Mine was a pain to get going as well.

That is pretty funny that the FWE is basically an unbent marconnet! That would make the FWE one of the oldest pulsejet designs around ;). I think we should look into his early prototypes, he had to make some kind of linear ones.

I think all our prototyping is really giving some good insight into how these things work.

Eric

The FWE/marconet is finally done and it looks great! I used some thin sheet metal this time and the final weight as shown in the picture is 17.8 oz, which is a hell of a lot lighter then the original FWE I built (29 oz with plug etc.)

I think I may run a test without the flare welded on just to see what happens (I assume that it will not run, but maybe I will be suprised)

intake length is about 108mm but I will probably make it adjustable (and put the flare on.)

Steve -

That's really a good-looking pipe! It occurs to me that without the intake flare, the exact position of your fuel outlet might be extremely critical! So, if it balks at starting, take some pains to vary that a little back and forth to try to hit the perfect spot. I'm guessing that the best spot will actually be out in front of the inlet just a small fraction of an inch. You should also play with a long stinger that goes all the way back to the aft end of the intake, and try varying the exact position of that a little.

These should be easy experiments with your bent fuel tube and hose clamp design, and could really yield some important results, especially to mini-Lockwood builders, et al.

L Cottrill

Sorry to dissapoint you larry, but I already welded on a flare before I saw your post. I changed my mind at the last minute because I pretty much convinced myself that there was no way it would run without the flare.

I attempted to run it today using Eric's starting method (mapp gas heating the CC wall bright red) but couldn't even get a pop out of it!
So tomarrow I will install the huge sparkplug and hopefully be able to test the engine again sometime over the weekend.

Steve where is your fuel injector situated? If you dont have it right even with the flare I doubt it will be mixing well enough for the heated wall startup. With my setups I can usually turn on the gas and have it rev up for a second without any air at all. If you have good fuel mixing it is ridiculous how easy starting an engine can be.

Eric

Just surfing for a huge spark plug for Steve. http://americanhistory.si.edu/scienceservice/012015.htm
I found this platinum site, kind of interesting.
http://www.theodoregray.com/PeriodicTab ... ex.s7.html
Mark

If you were making an ultra-tiny pulsejet, making it out of platinum would provide ignition over the entire surface area. Platinum will ignite hydrogen el pronto, the fellow who invented the word catalyst sold 20 thousand of his lighters in Europe I believe. It used something like a metal and sulfuric acid to generate hydrogen which when passed over the platinum material, ignited. You can do the glow worm experiment (which makes a lot of formadehyde you will notice) by using platinum wire preheated and coiled over some methanol as I have mentioned before. If you have a fine high surface area platinum bead it requires no preheating. You can also do the glow worm experiment using ammonia too. And you can substitute fine copper wire for the platinum but it will melt eventually. Hot copper gauze with methanol vapor passed over it with limited amounts of air is one way how industry make formaldehyde.
I don't know if platinum would be any better than iron, once something is glowing yellow hot, it probably doesn't matter? Platinum has a higher melting point though--1768 C or 3214 F
Mark

Mark wrote:If you were making an ultra-tiny pulsejet, making it out of platinum would provide ignition over the entire surface area. Platinum will ignite hydrogen el pronto, the fellow who invented the word catalyst sold 20 thousand of his lighters in Europe I believe.

I have considered electro plating the inside of my PDE CC with platinum to help crack fuels. Other possibility is just to use a platinum spark plug. Even when you are not using the spark anymore, at least you have a little platinum cataslyst.

Ogge wrote:I have considered electro plating the inside of my PDE CC with platinum to help crack fuels. Other possibility is just to use a platinum spark plug. Even when you are not using the spark anymore, at least you have a little platinum catalyst.

Another thing you could do is have ordinary glow plugs at staggered intervals around and along the chamber. They would never have to be powered, just contributing the catalytic action of their little coil elements. Whether this would be cheaper than plating or some other method would just depend on how many you think you need.

Catalytic action is something I've never had explained to me in any coherent way. All I know about it is that a true catalyst doesn't end up permanently modified [e.g. oxidized] by the reaction. Is it just a matter of having just the right valence? If that were the case, it seems like dozens of elements would be catalysts for thousands of possible reactions. And yet, it must boil down to the thing being able to either throw an electron from its outer shell and immediately recover it, or absorb an electron and then vomit it back out. Highly useful, but to me, incomprehensible. [Of course, I haven't bothered to look it up any time recently, either.]

L Cottrill

An now, for the moment youve all been waiting for:
IT RUNS!!!!!

(happiness)

Of all the FWE versions that I have tested this one performs the best IMHO. I consumes even less fuel then the original version of the FWE and has very little gas ejected out the intake- I was able to hold my hand within three inches (not an exaggeration!) of the intake without getting burned (and it didn't seem to have any adverse effect on the engine either!) The gas comming from the exaust was also suprisingly cool and also seemed to be generating a good deal of thrust. I will definately have to take some thrust measurements with this one! Starting was difficult at first because I kept overfueling it! I have rarely run an engine that likes such a lean mixture. I assume that this probably has something to do with the lousy fuel injector which I simply took off the last experimental design. This is another area that can no doubt be improved and I may do some experiments with eventually.

All shall bask in my reflected glory!!!
;-)

Looks good! You should clamp it at the front and back of the engine to see how heat spreads down the pipe. Even with the vise acting as a giant heat sink it looks like it wants to get pretty damn hot. Congrats

Eric

Steve

IMPRESSIVE!

I may have something to help with your fuel control issue. A stainless steel spray jet nozzle with a 1.5mm outlet and 1/8â€