Thought this might be a good place to start.. Anyone know of a site that might have info on how to get a Dynajet going?

One of our club members has a kit for some kind of speed ship, engine and some sort of OS igniter thingie. I thought it might be a hoot to get this thing together and terrorize the neighbors so I have volunteered to build the kit and see if we can't get it flying.

None of us know anything about Dynajets so it should be exciting, haven't seen the airplane kit yet but Tom says it will need some kind of dolly.. The field is grass so thinking 3 inch or so wheels but not sure how to build a dolly that will let go of the airplane at the right time.

Going to go see what google has to say but stopped here first...

Bob, DynaJets and grass fields don't mix well. Especially if the grass is dry! The other consideration is takeoff. Unless they have been improved since I used to do it, DynaJets require a very smooth surface to get airborne, for a couple of reasons.

First, fuel draw is marginal, and any interruption or inconsistency will kill the engine. Second, most jet planes are oriented toward speed and/or training, and have very small wings for their weight. Wing loading is more like full-scale aviation, measured in lbs./sq. ft., and not in oz. This necessitates a long takeoff run to build flight speed, and any roughness (aside from engine-run problems) slows acceleration considerably. A grass field which would present no challenge at all for a PA craft could easily be totally impossible for a jet.

I'm not saying that it can't be done; virtually all problems yield to some combination of money, time, money, clever problem-solving, money . . .    I am, however, suggesting that you're borrowing a bunch of extra difficulty in this task. Good luck.

Ralph

Dan Banjok flies an aluminum Mig powered by an OS pulse jet, the engine a scaled down Dyna jet. Lots to master and adjust. It also bursts into flame now and then, which mean better have a fire extinguisher handy and manned. Bob Wilke in Reading PA helped Dan a lot with fuel choices, starting drill and extensive trouble shooting. Dan is an excellent nuts and bolts engine man, also determined. It took quite a while to get the OS Pulse jet to fire up and fly. Many, many, issues. I would not try Pulse jet without a knowledgeable mentor to assist. The OS, of course, is a rare pulse jet, don't even know of another one flying in the US. The Dyna jet by comparison is heavily supported. Many more of them in use. Enthusiasts making parts available. Even updating and improving the original.

Bob
Sounds like we are going to have some lunch time entertainment at the next Tulsa contest 
Looking forward to it!!
Later
Jim

You have no idea of how loud and how "nasty" the sound of a Dyna-Jet is. You're going to have some irate neighbors. Just clamp it to the tailgate of a pickup truck and drive around on New Year's Eve and fire it off down at places like Mickey D's, and the BK, while in the drive-through. That's actually what they were meant for, ya know...well, that and as a "counter-thumping stereo devise".   Steve

Bob,
Bill Capinjola flew his jet(s) at our Titusville field, about the same time you were here visiting a few years ago. Good source for info.
Have fun, wear ear protection!!!!!!!!!
Roger V.

Hey Bob; Just between you and me and the Dynajet, don't let Joe Gilbert fly it. He will try to do the Mirror Meet Pattern with it. 

Hide the women and children. I see a bolo wingover coming.

I can see the beginnings of 'Jet Joe"   
You're going to have to hurry to get it done for the Contest!!    
Later
Jim 

Bob,  Shoot, you haven't lived till you have a jet chasing you. I believe it was sometime around 1958 in Atlanta, Ga when my jet turned in on takeoff and headed straight for me. It made a perfect circle passing  not more than five feet from me and continued in a perfect circle, lines straightened out and jet took off and got an official clocking. I didn't have sense enough to be scared back then. S

Make sure you video the first flight and put it on you tube ( and here )

Dan Banjok has built a Dynajet stunter. Does every maneuver in the pattern.

This is an early flight. Could be the first flight. At Reading PA.



This flight is probably the most recent. At the Huntersville contest last October.



There's a thread on Stunt Hanger about Dan and this plane. Some of the specs. Tank is an 18 and 1/2 ounce chicken hopper with extra baffles. Flight time about 3 and 1/2 minutes. Engine is not run on pressure. The cg shift during the flight is considerable-- tank is located in front of plane. Lap times under 4 seconds. The flight time is the main limiting factor. Not quite long enough for an official pattern. The teething problems for this project have been moderate, much less than some other Dan flights of fancy.

I am not sure of the ignition box. I think it's a bunch of batteries. Press, if you connect in the wrong place, the zap gets your attention. At the jet speed circle at the Nats, compressed air is mostly used. Danny uses a bicycle pump. New victims are lined up at each startup. The record is 10 minutes of non stop pumping. If you have back trouble, if you are over the age of... forget it. Initially the pump got pumped for a half an hour before the jet lit off. Now-a-days Danny has trouble shot the jet pretty well. Light off can happen quick. When the fuel mix is right, and the correct metering jet is chosen,  light off can be as quick as a few pumps. Issues. Start up conditions differ in barometric pressure/humidity/elevation/temperature. Metering jet needs to be matched to these factors as well as the "XXXX" factors no one is clear about. At the Jet Speed circle at the Nats, guess what, lots of flights don't happen. Jet won't light, jet dies out after a lap or... Dan can hear rich/lean sound when jet lights off. He adjusts the metering accordingly. The jet always has one sound for me, loud. Dan got better at predicting the metering jet, at the beginning of the flight day, on the basis of () hairs on the back of his neck (?) the tingles on the tip of his tongue (?). It's a mystery. The pulse jet petals are prone to breakage. New petals need to be inspected and fixed if necessary. These petals are punched out of metal sheets, at times this causes a ridge around the petal outlines that needs to be honed off. Fuel mix is critical and frequently problematic since propylene oxide is hard to come by. Might even be illegal. Propylene oxide helps all kinds of fuels mixed. The Dynajet has run on 87 octane, but the metering jet and the whatnut factors conspire to make this a difficult ignition.

Best option is to find an old head that knows these weird beasts. Good jet runs are 3,4, or 5 times as difficult as figuring a good 2-stroke run.

Also there's a sweet spot on which to direct the start up air. Mike Palko knows where. Dan Banjok knows where. The secret information is passed on to whoever directs the flow. I learned early on not to volunteer for this. Since, at times, the FLAMES OF HELL have erupted. Kneeling down next to the jet holding the 10inch tube, a bad idea for me, since these days it takes minutes for me to recover a standing position from a crouch. If you're at Brodak or Nats pick Danny's brain. Buy him a coke. (Not a Pepsi, for crissake!) This usually improves his mood.

Dennis,
It's been a while since I flew jet but I can tell you the one trick if you are using a hand bike pump is to drill out the end to eliminate the valve depressor or just cut the screw end off. The tank setup is also critical to good starting, the pickup line and vent needs to be 5/32" to 3/16" tubing for good fuel draw (1/8" won't work well). Make sure you have a strong battery for the buzz box.

When you begin the starting process tip the jet up at about 10 degree angle, put a small prime in the throat, start pumping and hit the buzz box. If the jet fires with flame keep pumping to blow out the flames. You will need a smooth takeoff strip and about 1/4 lap length. If you have good fuel, a strong pump and a hot spark it will fire in a couple pumps. If you do a search on this forum you can find Dan B's demo flight at the NAT's, it is really cool. Good luck let us know how you do.

Best,           DennisT

I know some will tell you to run different fuel but I have no experience with that. We were not competing, just making noise and having fun. Like I said easy starting, steady runs and cheap gas. We would get about 15 to 20 flights on a reed valve, before breaking them. It went about 115mph on 60' solid lines. My father passed in 1986 and I continued to fly the airplane until 1992 or so. Then this summer I pulled it off the wall and completely rebuilt and painted it. I have a dozen or so reeds and the buzz box still works fine. Waiting to get up to Bowling Green KY to use their nice paved circle for a flight. I can tell you from experience pulse jets love smooth surfaces for take off. Any bumps and you'll get an air bubble and it will quit. This is really the biggest problem we ever had. Smooth surface and a dolly- your in business.

   Exactly what we found as well, getting it off the ground through the takeoff roll without killing it was the biggest problem.

    Brett

For the stunt plane Dan had found that the metering jet was very critical and must be the right one for ambient conditions.  When he has it all correct it goes right away like the video shows.

Still  waiting  to see the  square eights  !!!   

Randy

   We figured that this was part of our problem, too, but (1) had no other fuel jets and (2) wouldn't have known whether it was too rich or too lean.

    It spewed some flames, made a lot of noise, and melted somebody's nylon jacket, so we figured it was a stunning success.

    Brett

Big long flame   too large on the jets  ,   small flame  too small on the jets 

Randy

Maybe Mike Palko will chime in here, he knows the specifics of the starting drill. Jet size, fuel mix, where to aim the air stream... Dan doesn't own a computer, will not use EZ pass or a cell phone. None of those technologies appear in Norman Rockwell paintings. None of these technologies existed in 1950s. So. The spark box is a model T coil plus batteries. High voltage, low amps. The hand pump is drilled out, there is a tube attached to the end. Starting issues almost always relate to jet size and fuel, unless the reed is fractured, a common problem. When the flames happen, we keep pumping and blow them out. Early on we'd use the fire extinguisher. Now we try to avoid this. The clean up is a pain, the foam corrosive.

...Dan doesn't own a computer, will not use EZ pass or a cell phone. None of those technologies appear in Norman Rockwell paintings. None of these technologies existed in 1950s. So. ..

I bet Dan still has a Western Electric model 500 rotary phone at home.  His camera is old school, it looks like a 1960s vintage rangefinder 35mm job.

We joke about slipping a cell phone in his pocket at the Nats so we can call him and remind him to quit goofing around on the grass circles and get his butt up to the L Pad for his official flight!