Big Lockwood starts by itself when cold

Bruce · Post by **Bruce** » Fri Oct 17, 2003 10:56 am

I fired up the big (200-lbs thrust) Lockwood today for the first time and observed something very interesting -- it didn't need any forced air.

There was a bit of a breeze blowing, but only about 8-10 mph. I turned on the spark, turned on the fuel and away it went all by itself!

It only does this when it's cold though, restarting when hot requires the blower as you can see in the attached picture.

Bruno Ogorelec · Post by **Bruno Ogorelec** » Fri Oct 17, 2003 11:26 am

Jesus, it looks like Apocalypse Now! How did it go... I love the smell of napalm in the morning !???

Bruno

Bruce · Post by **Bruce** » Fri Oct 17, 2003 11:38 am

I haven't gotten around to measuring the thrust yet, but suffice to say that it's just as well it's anchored to that concrete pad with a 20mm bolts!

The fuel system is using the same needle-valve setup as for the kart (regular 55-lbs Lockwood) so I'm guessing that it's currently only getting about 1/3 of the fuel it needs -- since the 55lb engine will run with the taps wide open.

New fuel system will be fitted tomorrow.

By the way, I notice now that the new 9Kg propane tanks have a little valve in them that shuts off the flow if you try to draw liquid from them by turning them upside down. Fortunately I now have a couple of 47Kg liquid-draw tanks -- should last about 10 minutes on this engine me thinks.

Pieter van Boven · Post by **Pieter van Boven** » Fri Oct 17, 2003 7:41 pm

Hey Bruce, why don't you make a U-bend on your leafblower so you can take a more safer place behind the engine-exhaust?

Pieter.

Bruce · Post by **Bruce** » Fri Oct 17, 2003 10:05 pm

Where would be the fun in that? :-)

I've always thought that from a starting perspective, the Lockwood was an akward design -- you push air in one hole and lots of flame comes straight back in your face.

However, all one has to do is stand slightly to one side, stay low, and know what to expect.

That's the good thing about conventional (valved) pulsejets -- when you blow air in the front, you're blowing the flames away from you.

I've added a starting-feed for the X-Jet so that it fires up using just a short burst of air from the compressor which is fed in through a connector on the side. I've also built a simple ECU that controls the flow of air/fuel and ignition for the X-Jet. Although it doesn't *need* this, it does make starting no more complex than just pushing a button.

After years of blowing in the mouth of pulsejets to get them started, there's almost something quite sophisticated about an engine that starts without a leaf-blower :-)

Tom · Post by **Tom** » Sat Oct 18, 2003 8:17 am

Hey Bruce,
it would seem that you have made a mark with your LCCM, as i have half of my triple award science set talking about it, and now they are expecting me to build a PJ, as i said that i knew all about it :o) ah well, thanks for giving me something to do.

:o)

T.

Bruce · Post by **Bruce** » Sun Oct 19, 2003 9:51 pm

Glad to hear that it's fostering some interest in the technology. There's going to be a whole lot more people (in the UK at least) talking about pulsejets and getting the "bug" by this time next week -- but my lips are sealed.

Bruce · Post by **Bruce** » Mon Oct 20, 2003 2:58 am

There's now a video of the big lockwood starting all by itself at:

http://www.interestingprojects.com/crui ... starts.mpg

I'm currently encoding a much bigger video that shows what's on that concrete pad and has some "up close and loud" footage of the engine running.

Bruce · Post by **Bruce** » Mon Oct 20, 2003 6:09 am

And I've just added video of the very first start (with all the flames and stuff).

This was before I discovered the technique to starting the engine without a blower.

It's at:

http://www.interestingprojects.com/crui ... balls1.mpg

Grant · Post by **Grant** » Mon Oct 20, 2003 12:55 pm

Hi Bruce,

Awesome Video! Just wanted to compliment you on the Lockwood and on the location. Pulse-jets and NZ country...Luverly!!

Bruno Ogorelec · Post by **Bruno Ogorelec** » Mon Oct 20, 2003 6:38 pm

Bruce,

Good stuff! Brings back the reasons why I got interested in pulsejets to start with, all those years ago.

The way the big 'un starts by itself is quite impressive. More proof of how important the boundary conditions are. Pulsejets obviously have to be BIG to work without fuss. The surface/volume ratio is very important. In small pulsejets, the processes in most of the volume are governed by boundary conditions, which makes functioning difficult.

I love this! Congratulations.

Looking forward to the Scrapyard Challenge and the pulsejet documentary.

Bruno

Bruce · Post by **Bruce** » Tue Oct 21, 2003 5:30 am

It was sunny again today and I replaced my fuel lines with larger stuff (went from 5.5mm internal to 7mm internal).

Here's the results -- another autostart and more boxes:

http://www.interestingprojects.com/crui ... epower.mpg

Nick · Post by **Nick** » Wed Oct 22, 2003 8:46 am

Hi Bruce et al,

does anyone have any idea when the pulsejet program(s) is/are on uk tv?
Presumably they told you something Bruce?

Nick

Bruce · Post by **Bruce** » Wed Oct 22, 2003 10:30 am

The Scrapheap Jet Car challenge is on this weekend (Channel 4).

It will screen in the USA in about five or six week's time on The Learning Channel I think.

Nick · Post by **Nick** » Wed Oct 22, 2003 11:27 am

Brilliant! I'm setting up the VCR now!!!

Nick

www.pulse-jets.com