User Manual

https://www.rcgroups.com/forums/showthread.php?2027012-HobbyKing-Pulse-Jet/page46#post36813306

Hobbyking pulse jet starts easily with bicycle pump and one very easy adaption

Let me first say the build quality of the pulse jet from Hobbyking that I received is just good. On the outside the

only weld visible is ringshaped, connecting the tube to the combustion chamber, and that weld looks very tight

and evenly done. On the inside lengthwise a weld is visible, and that one also looks very straight and even. No

grinding of welds visible on any part of the pulse jet (as seen on the earlier ones sold). The welds are most likely

machined. And the tube is round as it should be, not oval shaped or so. The Red Head is also machined very

nicely.

Now for the part on how to get it running. I have seen many video's showing people with enormous air

compressors trying to start the pulse jet. Complete overkill. It works as advertised: you just need a standard

bicycle pump and 5-10 strokes to get it started. Really easy (see video)! Of course it is necessary to connect the

pump properly to the air inlet. You need a so called Dunlop valve. Saw off the lower part of the valve (see

picture), file it even, and screw it onto the air inlet (it is exactly the same screw thread). Of course a proper

bicycle pump is needed which fits the Dunlop valve.

One very important, but also very easy, adaption is to widen the fuel nozzle (the brass part) to a diameter of 1.0

mm. The one I got had 0.9 mm diameter, and with that I could get the pulse jet started, but it would not

continue to run, because it just did not get enough fuel. Going from 0.9 mm to 1.0 mm diameter seems to be a

very small increase, but throughput area increases with some 25 %. The diameter can easily be measured (and

increased) using a set of drill bits with 0.1 mm step sizes (see picture, obtained cheaply from Chinese sellers).

Setup: regular 95 octane gasoline (petrol). Spark plug at 7 o'clock, air inlet at 10 o'clock. 3D-printed fuel tank

brackets

Temperature this morning was a cold 7 deg. C, but the pulse jet started without any problems (see video),

multiple times in a row. Very pleased with it. Next phase: add an electric fuel valve for safety, and put it on a

skateboard Holes for screws to mount it drilled already.

Hobbyking pulse jet start with bicycle pump http://youtu.be/2BToiH_RGks (0:25)

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https://www.rcgroups.com/forums/showthread.php?2027012-HobbyKing-Pulse-Jet/page46#post36813306 Hobbyking pulse jet starts easily with bicycle pump and one very easy adaption Let me first say the build quality of the pulse jet from Hobbyking that I received is just good. On the outside the only weld visible is ringshaped, connecting the tube to the combustion chamber, and that weld looks very tight and evenly done. On the inside lengthwise a weld is visible, and that one also looks very straight and even.