Help! Valved 'Brauner Type' Pulse Jet Engine Won't Work

[iris]

Hello All,
I have a 'Brauner Type' valved pulsejet engine that I made and can't get it to run. I designed it per available dwgs. and the pulsejet engine calculator which generates dimensions. All it will do is pop once or twice. It will not run continuously. I have the proper spark plug and had a correct fuel injector that I purchased from Earl Baily. Over the last couple of years I lost it. The valvehead is made of T6 6061 Aluminum and was made by me on a CNC lathe. The combustion and resonator tube was made by me of fully welded 14 Ga. carbon steel. The reed valve has made of the proper material contrary to what the dwg. states. Please see all the dwgs. and pictures.

Simply put the venturi area in front of the valvehead is not pulling a vacuum hence, no propagation of the firing process. I've been told that the combustion and resonator tube is too short. However I now have no access to metal working equipment and welding machines to experiment with by welding in splice pieces of the tube to get it to run. Does anyone have any ideals about why it won't run. I'm using Red Max designed for this engine.

Would anyone want to work on this engine and get it to run at a resonable price. Help!!!

Gene Border

[Bruce Simpson]

Looks okay, where's your fuel atomizer?

[Mark]

The thread is a common 1/4 inch 20, and if you look around you might find a screw made of soft brass with that thread to make a fuel metering jet at a hardware store. Then you could fashion a crude replacement by just drilling a hole down the center of the screw and one hole crosswise for the fuel to flow out of like the Dynajet which just had two exit holes for the fuel to be aspirated instead of 10 little holes on the Bailey. You can do without the blowpipe air injector by using compressed air angled in over the holes on your metering jet. You jet looks fine for starting to me, you just need some fuel I think.
Or you could get a rod of aluminum and use a die to make/cut the threads. Or you could even use an iron screw if you didn't mind drilling into a harder material.
The blue pulsejet in the picture below is a Bailey jet, the engine your plans are from. The red Dynajet on the far left is very similar to the Bailey jet. The head of one will screw onto the body of the other, and the same with the metering jets. The reed valves or petals are also the same. The spark plugs are different sizes and the Bailey is a few ounces lighter. In the center is a smaller Tigerjet.
http://www.lowes.com/ProductDisplay?par ... l=nofollow
http://www.google.com/images?hl=en&q=1% ... a=N&tab=wi

[dynajetjerry]

Mark,
I hope you don't resent my nit-picking. The Dyna-Jet predates the Bailey Sport by about 45 years. Your picture implies otherwise (to me,) and I've gotten a little touchy now that I'm the only still-living alumnae of Bill Tenney's Aeromarine Co. I'm also bothered by the misleading (to me,) history of Curtis DynaFog, Ltd. as shown on their web site.
Please don't be offended.
Jerry

[Mark]

Hey Jerry,
I spent many hours on the phone with Earl Bailey before he died. And of course the Dynajet is far older than the Bailey copy. When Gene Border asked about his Brauner type engine, he posted some plans of the Bailey jet, and remarked that he lost the Bailey metering fitting. I merely mentioned the fact that my posted picture on the right was that of a Bailey pulsejet, the same as the plans he posted at the top of this thread. And I mentioned that the Dynajet parts will thread into the Bailey jet, that the engines are basically interchangeable. I wasn't out to imply the Bailey pulsejet was some wholly original design or older than the Dynajet. I did say that the Dynajet is like the Bailey jet, but maybe I should have said the Bailey jet is like the Dynajet. It's just the way the conversation developed. I'm not out to rewrite history. ha

"The blue pulsejet in the picture below is a Bailey jet, the engine your plans are from." (The plans Gene posted are of the Bailey pulsejet, which are like you say mostly a Dynajet design.) (And granted the drawings aren't very good of the Bailey jet, also listed/shown in the plans section of this site. They seem to be a hodgepodge the closer I look at them.)

[dynajetjerry]

Mark & All,
Thanks for the clarification. I've got to stop reading into pulsejet writings things that are not meant. As my friend Jerry Nolin used to say (not an entirely original comment,) "Get over it!" I'll try.
Jerry

[Mark]

"Simply put the venturi area in front of the valvehead is not pulling a vacuum hence, no propagation of the firing process."
One thing I used to do is mist the insides of a pulsejet with methanol and then lightly block the tail end with an obstruction of cork or rubber stopper to gain a little bit of compression. Then with one hand cupped over the intake of the pulsejet and the other flipping the switch to the ignition, the jet fires like a potato gun and you can feel the vacuum on your hand when it does. If you prime the valve head and intake region with a little extra methanol there too, say a few misted squirts from a spray bottle of methanol, sometimes a fussy jet will rev up and bark using this method. You can hear it want to start so to speak.
Or if you are crazy like me, I have this old story of how I did something like that with a Dynajet but just lit the tail end with a lighter and it not only reved up, it sprang to a full roar for just a second out of the blue. The crazy part was that I was holding the jet with one bare hand and lighting the tail end with the other, just toying around without even a fuel tank and about the third try or so it surprised me big time. ha

[Rocket Man]

Those meter fuel jets are very tricky. I have made several in my lathe and mill and for liquid fuel 3 idential fuel jets will all work a little different.

To test the engine, what works best for me is to connect propane to the fuel meter jet. Use a pressure regulator to get the amount of fuel you need.

First turn on the high voltage. Next turn the air then turn on the fuel. Turn the fuel pressure up slowly until the engine begins to fire. The engine should start about about 40% throttle. Continue to turn the pressure up and the throttle will increase to 100%. Listen to the sound of the engine you can tell when it reaches full throttle because once you pass 100% throttle the sound started to change. The engine will run lean fine but it will not run very rich. Once you pass 100% throttle more than about 5% the engine will stop running.

Once you determine the engine will run on propane then all you need to do is change your fuel meter jet so it will run on liquid.

If your reed valves are opening too each the engine will not suck enough vacuum to suck in fuel. I have several engines and some factory engines use .006 and .008 and .010 thick blue spring steel. If you use .010 on all the hobby engines they run much better. There are several other very simple modifications that will improve the engine. Put a sheet of 400 grit sand paper or emery cloth on a flat table or sheet of glass. Slide your aluminum head over the sand paper to smooth the surface do the reed valves too this will make them seal very well.

Remove the spark plug and use fuel injection in the spark plug hole. This is a big improvement. Start the engine with a hand torch at the tail pipe tip.