Can't get 'em to run.

[Heath Daily]

My twin lockwood set-up just won't go for me.

Both engines exhibit the same problems, they will run and sound just like the video clips I've seen, but only with lots of forced air (shop-vac) They will run stronger with more fuel up until the point where the sound becomes slightly more rough / uneven / sloppy sounding. If it gets just a little more fuel than that, it will cease trying to run and just get big billowy flames. Pulling the air away will lessen the intensity of the engine until it just quits. Two or three times, it got a little more intense when everything just lined up perfectly and developed enough thrust to rock the bike, but it wan't much and didn't last long.

This picture is from one of the few times it was trying to burn in the tailpipe only, you can see where it's red. But it does show where I have to put the shopvac hose to get things moving. If it gets more than 8 inches from the intake it can't be coaxed into doing anything but big billowy fire.



This is a short video on youtube that shows it trying to run on forced air.
http://www.youtube.com/watch?v=1u2odzbfv70

I'm stuck. Any ideas how to coax it into running, or did I produce a dud design?

[NickC]

your design seems to suck....

[Heath Daily]

Forgot to mention I've got most of this up on my site with pics.

www.weblimbo.com

[Mike Everman]

I see no inlet flares, for one. It really is important for the intake of air.

Before running two, definitely get the configuration stable for one alone.

When you try to run both, very interesting things happen, but really, get that single motor running well first!
Apologies if I haven't read all leading up to this, and if I've missed that you've got one going well...

Looks like your intake is quite a bit longer than your combustion chamber, and the CC is quite large in diameter compared to the intake. Not that it's bad, just observations.

[Eric]

That doesnt look or sound like nearly enough air. Try a leaf blower.

What kind of injectors are you using?

Eric

[Mike Everman]

Agreed. I just watched the video. You need capability of blasting it with air from a bit of distance. Still think you need flares, at least, though I've had the occasional odd-ball that runs without.

[Dave_G]

My twin lockwood set-up just won't go for me.

I'm stuck. Any ideas how to coax it into running, or did I produce a dud design?

A lack of intake flares will not keep your engines from running. I've run many engines w/o intakes, because the flare itself was removable for adjustability. They will run, but maximum power will be reduced.

Your intakes are too long and your combustion chambers are too short.

If you will post your intake dia., combustion chamber dia., exhaust throat dia., and final exhaust dia., I will post recommend lengths for the sections that should give you an operating engine. I don't guarantee maximum performance, but you should be able to get it running by correcting the intake length and combustion chamber length. If you want to list your current engine lengths that would be helpful as well.

Dave

[Eric]

Dont worry about changing the design at this point, lockwoods can be a bitch to start without a real strong air source. Until you try a leaf blower I wouldnt do anything differently, the semi-spherical combustion chamber is fine.

The intakes are a little large in diameter, but other engines similar to this have run. The lack of flare on the intake will cause it to breath more like an engine with smaller intakes anyway.

You need a good strong starting air source, this will let you turn the fuel flow up, and the grumbling will get stronger, and the pops and bangs more powerful, and soon they should start to get enough energy pulsing through the engine to kick it into operation.

When it gets close to running you shouldnt be able to stand near the engine without hearing protection.

good luck

Eric

[Heath Daily]

Injectors are a radial spray with 12 holes .070 diameter. They are mounted on 3/8 brake line and sit about even with the welded seam where the first hemisphere is at it's largest diameter, and are centrally located.



The exhaust cone is 30" long, 3.5" big end, 1.625 small end
The u-bend is 1.625 dia, 6"long on short leg, 13.75 on long leg, 3" radius through the arc.
Combustion chamber is two 6" hemispheres with a 3" long peice of 6" pipe separating them.
Intake is 2.25" pipe 13.75 long.

The dimensions were adapted as well as possible to fit available materials from the lockwood hiller calculator that I downloaded from somewhere around here. Specifically the "Lockwood-Hiller puls-jet calulator" ver 2.0 by Marten Klein from 2004

Should the design as it currently is prove unworkable, I'd probably scrap these engines and build a cleaner version of a more proven design. I may be able to contract out for a nicely made version locally, but I'd rather beat these first until I know for a fact that they're not gonna go.

Currently the sound level is bearable, in fact if you back it off a little it's almost pleasant. So........ I've got a ways to go. I think the neighbor will loan me a leaf-blower for the weekend.

[Dave_G]

First, I am not familiar with the Lockwood calculator you mention (“Lockwood-Hiller puls-jet calulator" ver 2.0 by Marten Klein from 2004â€

[mk]

ISpecifically the "Lockwood-Hiller puls-jet calulator" [...]

This one basically only scales the patent engine dimensions. Nothing more nothing less.
Someone should really delete that file, because it is rather misleading.
Well, it dates back to the time I was rather new to the subject.

[Heath Daily]

Well, at least it isn't scaled too far. If I went itty-bitty I could see it not running, but I oughta be at least close to the ball-park, right?

[El-Kablooey]

I think they will run just fine. Like Eric said, lockwoods casn be a real bitch to start, especially if you've never started a PJ before.

You may have to shorten an flare your intakes, but I don't think any more modifications would be neccesary for a running engine. Note that I said running engine, not optimal.

[jerry marra]

well good morning everyone, Eric ,larry, mike

im back!!!!!!!!!!!!!

will start to participate in the forum mostly on valveless engines.

i will start with pictures of projects at hand, i'm looking foward to contribute and help if i can. This will be this coming weekened.

The new shop is completed and all the eguipment is in place.

PS: My cancer just as to wait ,until these pulsejet projects are completed and i can be of assistance if i can to this forum.
Jet engines have been in my blood since i was 12, and i have many design ready to share ,so lets get started!

Thank you to all

pulso57

[jerry marra]

Sorry for posting my welcome in the wrong page,

regarding the two engines in this post,
i agree that the only thing i would change is the intake lenght abit "to long, as to the flare ,that could be done later, after it self sustain it will help and ease breathing and increase power.

But most of all, lockwood designs need a lot of air,as erik pointed out,a good strong leaf blower will do, you will be surprised as to the difference it makes for start up.

years ago, i tries an engine with a blow gun from a compressor, it had boiler nozzles,would not start,switched to a leaf blower and it stated immediatly.

thank you

pulso57