www.pulse-jets.com

Bruce - You are quite right -- that works, and can be a useful training technique for beginners. The flaw is that a beginner may wrongly assume that every time he picks up the handle, "neutral" control will always be found at the most natural angle of the wrist. Once he learns that neutral may feel ...

Thanks, Mark -- I was actually surprised at how good an article that is. And, it is correct that, generically, we should call it "control line" flying since U-Control is, in fact, a trademark name. However, there are thousands of us who will always think of control line flying as "U-Control", especi...

Metiz - I hope you will forgive this blasphemy as it stems from a lifelong prejudice and will be slammed by just about everybody, but here goes: Why radio? If the point is to experiment with liquid fueling while training yourself to fly a model while at the same time avoiding the destruction of life...

Well, the rigid line worked great. However, my testing was finished almost immediately because I had under 20 lb of propane left -- in a matter of minutes the bottom few inches of the cylinder was frosted up, and the regulator would no longer respond to demand. So yesterday, I got the 50 pounder re-...

Nice find, Jutte! The Enics stuff is always so beautiful to see. Man, I always think it would be so much fun to be able to see their designs up close, like at a military trade show or something.

L Cottrill

I added a 5 ft section of 3/8 inch OD brake line to completely isolate the fuel hose from engine heat and flame. I reduced the hose length from 8 ft to 4 ft so it's just a short link to the rigid steel line. I put three bends in the line so that it's stable on the ground, not just dependent on the f...

"An unfolded FWE, not for propulsion. The client wanted high tail flame temps AND velocities. Exact usage is proprietary." If you ever find out or can say in the future, I'd be curious what he's planning to use it for. I'll be able to reveal it after his patent is granted. In the meantime, I have l...

Testing has been a rocky road. To start out, I was testing for a couple of weeks in February, but was hampered by terrible weather and got almost nothing accomplished. The client understandably became weary of this and insisted that I ship it down to Louisiana for them to test. It turned out that be...

About 45 minutes ago I was performing a test run of my big "industrial heater" engine, using the Sport Throttle attached to the output of a high-flow regulator. This was a high pressure fuel pipe test, with 60 PSIG set on the regulator. I got about a full minute of running, then suddenly the engine ...

Yet another new offering, for serious experimenters only. Use this anywhere a permanent tailpipe tuning device is needed or desirable. For example, you might want to tune for optimum length because of altitude variations, experimenting with widely differing fuels, etc. Designed by Larry Cottrill, ex...

I am now offering the following: 2010-02-22_002_crop1_small.jpg I don't have the sales page created yet, but you can order via PayPal. Note that this is essentially an "introductory" price -- it may go up some by the time I get the sales page up. It will certainly increase if the proposed Value Adde...

This is long, but quite astonishing. If you think "all the prophets are dead and gone", check out what Alexandr Solzhenitsyn had to say to an audience at Harvard University on June 8, 1978. We should have paid attention ... http://www.columbia.edu/cu/augustine/arch/solzhenitsyn/harvard1978.html L Co...

Nick -

CONGRATULATIONS! There is nothing quite like the first time you get one to take off and really go for you. "So THAT's how it's supposed to sound!" Ha.

L Cottrill

Vern - Well, these look great, but I'll run them with UFLOW when I get a chance (give me a day or two). You don't show any dimensions that locate the intake-to-chamber transition, but I can scale them. And with UFLOW I can adjust them fore and aft from there, to see what works. 2 inches would be pre...

First test session using the 50 lb tank. Still nothing better than some pretty loud growling. See video clip attached. I was actually able to experiment with the other fuel pipe a little, and I was able to do a LOT of playing around with the spouting location. The "low turbulence" fuel pipe was usel...