What size copper pipe to use?

[pulsejetter]

Hi all, i am building a 55lbs Lockwood hiller pulsejet from some plans which i found on the internet and i belive them to be the same as Bruce Simpsons.
I am wondering what size copper pipe people use so i can buy the relevant pipe and ball valve.
Also does anyone know what to replace the regulator on the propance tank with so it's free flowing?

Any help is appreciated.
Thanks.

[leakfree]

I don't think you want to use copper at all. I know the ball valve will not stand the heat. As for the propane tank it should be just a 1/4" galv coupling in place of the regulator. Teflon tape the nipple and hose male adpt good and you should be set.

[pulsejetter]

I don't think you want to use copper at all. I know the ball valve will not stand the heat. As for the propane tank it should be just a 1/4" galv coupling in place of the regulator. Teflon tape the nipple and hose male adpt good and you should be set.

I'm talking about the gas line being copper. I have seen people run copper gas lines with success. Including a ball valve and needle valve.

I was thinking of using a 1/4" copper pipe or 3/8" copper pipe to run as the gas line with the approriate size ball valve.

[coosgearhead]

I used a 3/8in copper tubing and had no issues.

[pulsejetter]

I used a 3/8in copper tubing and had no issues.

Thanks for the reply, looks like i'll be getting some 3/8" copper pipe then.

I've been searching for radial injectors to use with propane gas. Am i right in thinking the radial injector is for example a length of tube with holes drilled raidaly/ circular so that when inserted on a fuel rail into the combustion chamber transition cone it sprays the whole circular circumference?

Thanks for any help,
Pulsejetter.

[pulsejetter]

Anyone know if my identification of the radial injector is correct?

[PyroJoe]

Radial injector by Dang911 towards the bottom of the page.
viewtopic.php?f=3&t=2885&hilit=lockwood+startup

Advanced injector by Eric also at the bottom of the page.

Lockwoods typically require alot of starting air, and are difficult for a first engine.

[pulsejetter]

Radial injector by Dang911 towards the bottom of the page.
viewtopic.php?f=3&t=2885&hilit=lockwood+startup

Advanced injector by Eric also at the bottom of the page.

Lockwoods typically require alot of starting air, and are difficult for a first engine.

Great thanks for the link. Do you know how the injector shroud is held on on Dang911's injector?
It says a pin but i was thinking if this goes right the way through te copper tube then it may leak?

I always thought people decided to build a lockwood because they're a beginners engine, perhaps i misunderstood.
Thanks again.

[PyroJoe]

Not sure how he pinned it, maybe a press fit or hammered/distorted the ends to mushroom. A small leak wouldn't affect much in that location.

[pulsejetter]

Just thought that i'd post on here and say i built the lockwood hiller valveless pulsejet from plans found on the internet, used copper pipe as said above which is basically the same configuration as Dang911's pulsejet as i have a vapourisation or pre-heat coil if i choose to invert the propane tank for liquid propane.
I am running a non regulated 13kg propane tank which supplies easily enough fuel with a very small turn on the tanks needle valve.
The copper pipe runs into the intake and is centred, it is around 16" inches inside so is exactly in the middle of the transition cone. I have crimped the end of the copper pipe and drilled 6 small holes.
This works fantastic, the pulesejet will throttle very well and idles with only a tiny turn on the tanks valve.

I started it today by switching on the IC555 timer circuit with NPN transistor just after the gas valve was opened. Then directed the air into the intake via an electric leaf blower and away it went.
No adjustments needed, i was supried at how quick and easily it started.
Was extremely deep/ had a strong low bass tone and was loud when throttled. It throttle very well with me only turning the valve a little bit. I didn't want to supply any more gas as the engine glowed a cherry red just on idle.

Most of the combustion is taking place in the combustion chamber/ part of the intake and i think some of the u-bend.

No complaints so far which is good although i suspect some people were suprised.

[pulsejetter]

Here are some pictures of the finished pulsejet. Might include some build pics later on.

[PyroJoe]

Looking good,
Happy to hear the crimped and drilled method worked and many thanks for the details on the location. What diameter were the 6 small holes?

[pulsejetter]

Looking good,
Happy to hear the crimped and drilled method worked and many thanks for the details on the location. What diameter were the 6 small holes?

Thanks.
I'll have to get back to you on that, not really sure, just a small drill bit i had, i would say 3mm.
I either put 6 or 8 holes in, fairly close to each other
Drilled straight through 3 or 4 times to give the 8 holes.

[pulsejetter]

Hello pulsejetter,

I must say you have done a good job. Happy to see that you have finished your work.

Thanks, i should really upload a video sometime.