Pulse Jet Plans

8/2/2019 Pulse Jet Plans

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Pulsejet Engine

Plans

Warning:

For educational purposes only!

Pulsejet engines are dangerous. They should be built

and operated with safety in mind at all times.


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Introduction

Pulsejet engines are simple in contruction. A very basic discription of the internal contruction

ventura, fuel syphon, reed valve, combustion chamber,and resonator tube.

The function of the engine is not quite so simple. The sparkplug is for starting purposes only. T

engine is capable of running due to resonate compression. The sonic wave that is produced by

combustion is reflected back into the combustion chamber by the resonator tube. If the resonator tub

s tuned properly the sonic wave is reflected perfectly to produce a self sustaining cycle.

Combustion Chamber &

Resonator Tube

Materials

2.625" OD x .060" TW Low C/S Tubing

.25" OD x .060" TW Low C/S Tubing

2.625" OD x 1.25" OD x 2.60" L 14 - 16 GA. Reducer

Construction

Cut a piece of 2.625" OD tubing 2.40" long. Drill two 3/16 holes, 180 degrees from each other .2

rom one edge. Drill a 1/4" hole 18 degrees CCW from one of the other holes, 1.25" from the same edge

Weld the reducer to the side opposite the holes. This makes up the combustion chamber.

Cut a piece of 1.25" OD tubing 14" long. Flare one end to a diameter of 1.50", starting .625" from

he edge. Weld the end opposite the flare to the combustion chamber. Grind and polish the welds

smooth with the inside and outside surfaces.


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Reed Valve

Materials

006 Thick T303 Spring Steel

Construction

Cut a circle 2.20" in diameter. Cut ten flower petal shaped reeds to the specifications in the

llustration.


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Valve Retainer Washer

Materials

25" T6061 Aluminum Plate

Construction

Cut a 1.625" disc. Drill a 1/4" hole in the center. Bevel the edge half the thickness of the disc

one side leaving a .625" diameter flat surface in the middle. From the opposite side from the bevel, bo

a .56" diameter countersink, to a depth of .200". It may be possible to find a stainless washer that ca

be modified to these specs.


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Ventura/Valve Head

Materials

2.625" Diameter T6061 Aluminum Solid Round Stock

Contruction

The construction of the ventura/valve head requires the use of a combination lathe/endmill to do

precise work. If you have some experience with building jigs to use with a drillpress.

Cut a piece of solid stock to the length of 2.20". All the specs are for the rest of the machining

he valve head is in the illustration. The center hole, for the valve plate retaining bolt and the flow

njector, can be drilled first. Then, cut the step for the combustion chamber to slide over. At this poin

you need to drill ten holes thru the stock at 36 degrees using the specs on the illustration. Next, drill

wo holes 180 degrees apart,18 degrees clockwise from two of the ten holes previously drilled. These

wo being 180 degrees apart. Drill these two holes to the corresponding specs on the illustration. Ne

center bore from the opposite end from the end stepped to fit in to the combustion chamber. This as

well to the specs in the illustration. Blend the inside and outside of the intake to the specs to make th

ventura.


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Assembly

At this point, if you have followed the directions and done everythings to specs, you are ready f

assembly. But first, you are going to need some items that are easier to purchase prefab for this

pulsejet. The meter jet, flow injector, and sparkplug are these items. The sparkplug can be purchase

at most model shops. All three items can be purchased from Bailey Machining Service. Here is their

address and telephone number: Bailey Machining Service, 633 W. Parker Rd, Houston, TX 77091, USA,

713) 694 - 7017.

Take the valve head, reed valve, valve retainer, and a allen head bolt 1/4 - 20 UNC x 1/2 and fast

he reed valve to the head so that the reeds are centered over the intake holes.

Take the spark plug and install in the 1/4 hole drilled in the side of the combustion chamber, usi

a nut and sealing washer.

Take the assembled head and mount it in the combustion chamber with two #10 - 24 UNC x 1/4

machine screws and corresponding flat washers.

Insert the metering set into the flow injector and install in to the center hole at the intake end o

he intake end of the valve head.


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Starting The Pulsejet

To start the engine you will need a high voltage ignition system, a fuel source and a pressurized

air source. Start fuel and air going into the intake of the engine. After a couple of seconds start powe

o the sparkplug. When you start to hear a pop and then start a low pitch buzz richin the fuel until it

sounds stable and then remove the power from the sparkplug.

If the engine is tuned properly it should now run on a self sustaining compression cycle, withou

he need of the sparkplug.

Documents

Pulse Jet Plans