HPST 2020 Jet Engine

[praendy2203]

[notjet]

is that the start of a pulsejet???

[praendy2203]

Hi guys,

A little off topic.

4 days ago, I found a Yamaha motorcycle reed valve during searching Ebay for nothing😉

I bought it and some stainless tubes, to build a noisy toy for new year.

Yesterday I started to fit all parts together and today, all work is almost done.

It was a short weekend project, because the wheather is not nice for testing the jet engine.

The air intake is still missing and a fitting and a pressure regulator for Propane gas.

The resonance tube is also still too long.
I have to cut it to about 71-75 cm.

Maybe tomorrow first shot👍

Andy

[enginewhisperer]

many years ago I built a pulse jet using galvanised water pipe and fittings and a chainsaw reed valve.
Basically a smaller and less fancy version of this!

Initially I tried to make it work with the chainsaw carburetor, but didn't have much luck. In the end I just fed propane into one of the vent line fittings on the carb.

It certainly worked, but it was ridiculously loud, and the neighbours were not impressed!

In the end I decided to see how long it would run before the reed valve block melted. It wasn't very long!

[racket]

Yep , motorcycle reed valves work , I fitted mine into "horns" so that they weren't exposed to radiant heat or combustion gases

[praendy2203]

[praendy2203]

Hi,

Pulse jet finished.

Still waiting for the Propan pressure regulator.

Maybe tomorrow testing😉

Andy

[racket]

Hi Andy

Are you going to use gaseous propane ??

You might find that the propance cylinder valve will be all you need as a throttle .

PJs are thirsty engines , I had to invert my propane cylinder to get enough fuel .

Cheers
John

[enginewhisperer]

pulse jets are a bit quicker to build than turbines


Even my very small one worked fine on the cylinder valve without a regulator.

[praendy2203]

Hi,

here in Germany you will only find some strange adapters for a Propan cylinder.

I could not find a proper adapter to fit a flex hose on and all other adapters have a 0,5 Bar standart regulator.

I found a adjustable regulator from 0,5 - 4 Bar.

Because now we have -10°C I will put the cylinder in hot water.

Andy

[racket]

Hi Andy

Minus 10 C , nice temperature for a gas turbine or PJ , lotsa extra thrust :-)

LOL.......but not much vapour pressure in a propane cylinder, yep ,lotsa hot water :-(

Hope it all goes well

Cheers
John

[praendy2203]

[praendy2203]

Hi guys,

first start and almost running loud☺️

The spring steel is too thin (0,1mm).

Usually pulso builder use 0,25mm - 0,3mm spring steel.
I ordered a bit of both and will see if it works.

After some BRRRRRRRRR, the membrane is already bent in the open position, so the gases getting pushed back and leaving the air intake.

But... almost 100 Db reached👍👍👍

Andy

[racket]

Hi Andy

Congratulations :-)

I found that the reed valve blocks come with different levels of opening angle , I had to swap some of mine around to get a good mix of lift and reliability .

Looking forward to seeing some video once you get the new valves installed .

Cheers
John

[praendy2203]