big lockwood style plans see if you think it will work

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larry cottrill
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Re: big lockwood style plans see if you think it will work

Post by larry cottrill » Tue Mar 01, 2011 9:09 pm

55dcyinely wrote: Back ground pitcher of Lockwood Pulse Jet built from an exhaust system off a semi truck.
And foreground this little Chinese 2LB thrust. Hard to start, but runs.
IMGP0558.JPG
Note to 55dcyinely:
That foreground engine is not a Chinese type. It is an FWE - probably a build of Eric Beck's Advanced FWE design. Trust me ;-)

What's under that Lockwood? I can't tell if it's a pair of pontoons or a couple of solid rocket boosters!

Keith - sorry to cut in, I just couldn't let that FWE go misidentified. It looks like you're doing some really nice building there! I know next to nothing about liquid fueling (or liquid-to-vapor) fueling, but find it a very interesting topic for discussion.

L Cottrill

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Re: big lockwood style plans see if you think it will work

Post by keith mcconnell » Thu Mar 10, 2011 2:35 pm

I'm having problems with the engine flaming out at higher power settings and I'm only getting about 20 to 30 lbs of thrust. I'm thinking my exhaust is too small. Here is a draw of a redesigned exhaust. You guys take a look at it , if you don't ming, and tell me what you think. Thanks again for everyones help!

Keith
pulse_jet.pdf
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PyroJoe
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Re: big lockwood style plans see if you think it will work

Post by PyroJoe » Thu Mar 10, 2011 6:46 pm

Looks like the expansion in the tail could be shifted forward about three calibers. That somewhat shifts it from a beginners tail to a more advanced design. I usually come to the same conclusion when using the smaller diameters in the tail, it tends to feel small and the pressure tends to "dump" out the intake. I think Lockwood intended for his engine to run with a intake augmenter.

A augmentor on the proposed one would also be well utilized. Beyond that the fuel quantity and mixing becomes a paramount issue.
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Re: big lockwood style plans see if you think it will work

Post by keith mcconnell » Thu Mar 10, 2011 7:07 pm

PyroJoe wrote:Looks like the expansion in the tail could be shifted forward about three calibers. That somewhat shifts it from a beginners tail to a more advanced design. I usually come to the same conclusion when using the smaller diameters in the tail, it tends to feel to small and the pressure tends to "dump" out the intake. I think Lockwood intended for his engines to run with a intake augmenter.

A augmentor on the proposed one would also be well utilized. Beyond that the fuel quantity and mixing becomes a paramount issue.
Thanks for your help. As soon as I published the drawing I realized I had the wrong length between the u and expansion. I think I forgot to figure in the length of the u. My new numbers can in around the same as yours. Well I guess I'll start ordering metal and redo the exhaust. Do you think this new design might be able to get closer to the 100 lbs thrust I'm looking for? Also,with the "old" design, it is incredibly loud and actually vibrates the ground. Do you think the "new" design will be louder with more vibration or can I expect it to be about the same?

Again thanks for all your help,

Keith

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Re: big lockwood style plans see if you think it will work

Post by metiz » Thu Mar 10, 2011 7:25 pm

As a rule of thumb, the more you tune an engine, the louder it gets. Getting big thrust in a small package automatically results in a higher frequency (opposed to bigger engines with the same thrust) all those powerfull cycles realy tend to hammer in. My biggest tuned engine, the M40, has this effect to. even with good hearing protection, it is absolutely intollerable to get close to the tailpipe.
Quantify the world.

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Re: big lockwood style plans see if you think it will work

Post by PyroJoe » Thu Mar 10, 2011 8:20 pm

It will be louder, the frequency looks like it will shift slightly higher. The tail will clear and compress more volume of the CC so the amplitude will be the notable change.

I don't think it will flame out as easily as the current design. That tail is going to pump alot more air.

As far as the 100 lbs., I see some number that show that it could be possible. Fully augmented and pushed hard.

I say, see how much asprin consumption is required at 65lbs. and work your way up from there. Eventually it will become like nailing jello to a tree while herding cats.

Most light weight, ground based vehicles should do well at 60 to 70 pounds unless the drag is high, cross section is large or ground is soft.

What is the application anyhow?

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Re: big lockwood style plans see if you think it will work

Post by keith mcconnell » Thu Mar 10, 2011 8:36 pm

The plan is to put two of them on a kart racing frame. My goal is to push a kart 70 to 80 mph in a 1/8 mile. Kind of like Bruce Simpson's dragster. I think he said he was getting 160 lbs of thrust per engine. That's the future plans. It will be awhile before I even get the kart frame. Got to get these engines running right first.

Thanks for the help,

Keith

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Re: big lockwood style plans see if you think it will work

Post by PyroJoe » Thu Mar 10, 2011 9:09 pm

Ah,
Thats a tough one, Pulse jets are almost opposite of dragster engines, they are fairly slow of the line and don't pick up speed like you think they would.

Land speed racing is probably a better fit, where there is several miles of track to work its way up to speed.

Weight is kind of a double edge sword in karts, as it will need to be as light as possible to gain speed, but once it attains near 85 mph the airflow over the top of the kart tends to make them airborn. Seems I recall reading in the 60's they had alot of karts go airborn in California. The designs are probably better these days.

I like the way Bruce did his, long and lean.

The "Texas Mile" is just up the road from me, often I wish it was the Texas 5 mile.

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Re: big lockwood style plans see if you think it will work

Post by keith mcconnell » Thu Mar 10, 2011 9:17 pm

I might not be able to do it but it give me something to work towards. If nothing else I'll probably have the only pulse jet powered go kart in the state of Tennessee! :D

Keith

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Re: big lockwood style plans see if you think it will work

Post by PyroJoe » Thu Mar 10, 2011 10:00 pm

Its all good til the revenuers show up with a turbine kart.

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Re: big lockwood style plans see if you think it will work

Post by keith mcconnell » Wed Apr 13, 2011 2:17 pm

I've got finally got the redesigned pulse jet running! I was able to get it to running just on gasoline. The thrust is not there yet but I think this design is good. Just need to work on the fuel nozzles. Here is a video of the "new" engine. First part of the video shows a very close call with the engine almost flipping over backwards. Later in the video I took out the fuel nozzle and welded up two of the 16 holes. I'm not sure if that changed the engine or if I have a cracked weld some where but the engine changed how it sounds and the flame changed too. Take a look and let me know what you think. I think I'm getting closer!

Thanks for all your help,

Keith Mcconnell
http://www.youtube.com/watch?v=kVo-k9zGGTo

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Re: big lockwood style plans see if you think it will work

Post by PyroJoe » Wed Apr 13, 2011 2:43 pm

Yep thats the stuff!
Good work.
Is that straight up liquid gasoline?
If you haven't already tried it, might mix about 10% methanol with the gasoline. Typically found under the brand HEET.

A big jump in performance will probably be observed with an intake augmentor. Amazing its producing that much thrust without one. :shock:

Is the noise level a wee bit greater?

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Re: big lockwood style plans see if you think it will work

Post by keith mcconnell » Wed Apr 13, 2011 2:50 pm

PyroJoe wrote:Yep thats the stuff!
Good work.
Is that straight up liquid gasoline?
If you haven't already tried it, might mix about 10% methanol with the gasoline. Typically found under the brand HEET.

A big jump in performance will probably be observed with an intake augmentor. Amazing its producing that much thrust without one. :shock:

Is the noise level a wee bit greater?

Thanks! It is straight up liquid gasoline. I have to try the methanol. The noise is a little bit greater but you can tell a bigger difference in the "feel" or vibration. We actually set off the alarm in the build beside us. Cops come out and everything.

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Re: big lockwood style plans see if you think it will work

Post by PyroJoe » Wed Apr 13, 2011 3:07 pm

The methanol will add a little bit more oxygen to the fuel air mix and help it burn a little smoother, and faster.

I would advise against a vapor collar for the moment. One thing to keep a watch for is if the gasoline is trying to vaporize in the injection tube. This could create some fueling oscillations. As sometimes the fuel is spewing out the injector holes as vapor and sometimes liquid creating havoc. Looks like its doing good for now.

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Re: big lockwood style plans see if you think it will work

Post by leakfree » Sat May 28, 2011 11:38 am

Keith, I just read this thread and watched your vids this morning. That is some beast you got there! What are your latest developments on this project? I've been thinking about gas injection for my second build.

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