Weight of fuel to thrust

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marksteamnz
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Weight of fuel to thrust

Post by marksteamnz » Wed Oct 29, 2003 1:23 am

Does anyone have a figure for the kilograms of fuel consumed per minute vs the kilograms of thrust for a valved PJ in the 10 to 30 kg thrust range? I'm trying to size an off the shelf nozzle.
Cheers
Mark Stacey
www.cncprototyping.co.nz

Pieter van Boven
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Post by Pieter van Boven » Wed Oct 29, 2003 5:11 pm

Hi Mark,

I watched your site and pulsejet engine. It looks very good! Construction looks almost the same as my PJ90 copy.
http://pj-website.tripod.com
What are the dimensions of the engine, maybe you can use the same nozzle as I did.

Pieter.

Bruno Ogorelec
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Post by Bruno Ogorelec » Wed Oct 29, 2003 9:21 pm

Pieter is right -- it's a great-looking engine. Congratulations!

Bruno

marksteamnz
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Post by marksteamnz » Thu Oct 30, 2003 8:14 am

Thanks Pieter
I drew up the Digerido first with a ring bolt assembly system and then adapted that to the PJ90 plans but using standard size 0.5mm wall 100 and 63mm SS tube. Seeing your design showed I was on the right track. Scale up was by using ratios from the various PJ calculators.
The jet is a modified version of the PJ90 unit using a drilled bolt. This was the hardest thing to make as it required some tricky jigging, hence the query on flows as I'd like to find and off the shelf spraying systems replacement. Any sugestions most welcome
Everything else was drawn with CAD and then cut on my CNC mill.
This unit was sold but before petal valves could be fitted it was stolen in a burglary. Weird but true.
I'm working on a yet furthur modified version and once my high speed spindle is fitted to the mill I'll be cncing some valves
Pieter van Boven wrote:Hi Mark,

I watched your site and pulsejet engine. It looks very good! Construction looks almost the same as my PJ90 copy.
http://pj-website.tripod.com
What are the dimensions of the engine, maybe you can use the same nozzle as I did.

Pieter.
Cheers
Mark Stacey
www.cncprototyping.co.nz

Pieter van Boven
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Post by Pieter van Boven » Thu Oct 30, 2003 4:47 pm

Here is a picture of the nozzle I used in my PJ90 (the black one..) and some others wich I might use on an other PJ-project.
The one I used is a BETE PJ28 "pinn-jet nozzle" and I ordered it. I didn't want my engine to fail because of bad injection so this was the best way to get it running. The others are bigger nozzles except the round one. It has 6 verry small holes in the middle wich point in different directions (cone shaped). I think this would be a nice one to inject gas in some kind of valveless engine but this is just a thought.

Pieter.
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Mark
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Post by Mark » Thu Nov 06, 2003 3:33 pm

Pieter van Boven wrote:Here is a picture of the nozzle I used in my PJ90 (the black one..) and some others wich I might use on an other PJ-project.
The one I used is a BETE PJ28 "pinn-jet nozzle" and I ordered it. I didn't want my engine to fail because of bad injection so this was the best way to get it running. The others are bigger nozzles except the round one. It has 6 verry small holes in the middle wich point in different directions (cone shaped). I think this would be a nice one to inject gas in some kind of valveless engine but this is just a thought.

Pieter.
I just ordered a BETE PJ28 nozzle and a Cottrill-sized PJ15 from some place in Massachusetts. The specs describe an "impingement, 90 degree spray angle." The PJ28 says it puts out 0.15 gallons per minute at 50 psi or 0.11 gallons at 30 psi, or 0.65 gallons at 1000 psi. I must say these fittings are not cheap, at least from the place in New England, I'm spending $30 some dollars plus shipping for the two of them. You can have your choice of brass, 303 Stainless Steel, or 316 Stainless Steel.
The literature says the PJ nozzles, they have many kinds at the BETE web page, anyway the PJ impingement nozzles produce the "finest fog of any direct pressure nozzle," producing a high percentage of droplets under 50 microns. I think the nozzles are made for water and you can use them as a cooling device, humidification, misting, moistening, coating, and of course anything you can think of yourself. I can see tundraman formulating some sort of mind altering "Canadian Mist" delivery system.
I've heard of CO2 fire extiguishers producing static electric sparks, (not good for some kinds of fires) and I was wondering if tortuous twists and turns and high speed ejection might somehow be beneficial for speeding up the reaction of gasified fuels by imparting a static charge to them.

I wonder if the Lockwood engine would perform better if some "ideal" fuel injection system were found. The one they have pictured on their site seems to be a nice yellow hot over a large part of the duct. Also if you look closely at the picture with the two men with hearing protection, the jet has a starting air injection line I presume in the intake throat AND perhaps three or four other injection points plus a thick black wire which looks like the ignition cable. One of the lines might be a sensor but it might be that they are injecting propane in at least 3 different locals in the combustion chamber. Seems such a set-up would make for a more sudden, intimate fuel/air charge. Just something some of you might like to try.
Mark

Mark
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Post by Mark » Thu Nov 06, 2003 8:00 pm

Mark wrote:
Pieter van Boven wrote:Here is a picture of the nozzle I used in my PJ90 (the black one..) and some others wich I might use on an other PJ-project.
The one I used is a BETE PJ28 "pinn-jet nozzle" and I ordered it. I didn't want my engine to fail because of bad injection so this was the best way to get it running. The others are bigger nozzles except the round one. It has 6 verry small holes in the middle wich point in different directions (cone shaped). I think this would be a nice one to inject gas in some kind of valveless engine but this is just a thought.

Pieter.
I just ordered a BETE PJ28 nozzle and a Cottrill-sized PJ15 from some place in Massachusetts. The specs describe an "impingement, 90 degree spray angle." The PJ28 says it puts out 0.15 gallons per minute at 50 psi or 0.11 gallons at 30 psi, or 0.65 gallons at 1000 psi. I must say these fittings are not cheap, at least from the place in New England, I'm spending $30 some dollars plus shipping for the two of them. You can have your choice of brass, 303 Stainless Steel, or 316 Stainless Steel.
The literature says the PJ nozzles, they have many kinds at the BETE web page, anyway the PJ impingement nozzles produce the "finest fog of any direct pressure nozzle," producing a high percentage of droplets under 50 microns. I think the nozzles are made for water and you can use them as a cooling device, humidification, misting, moistening, coating, and of course anything you can think of yourself. I can see tundraman formulating some sort of mind altering "Canadian Mist" delivery system.
I've heard of CO2 fire extiguishers producing static electric sparks, (not good for some kinds of fires) and I was wondering if tortuous twists and turns and high speed ejection might somehow be beneficial for speeding up the reaction of gasified fuels by imparting a static charge to them.

I wonder if the Lockwood engine would perform better if some "ideal" fuel injection system were found. The one they have pictured on their site seems to be a nice yellow hot over a large part of the duct. Also if you look closely at the picture with the two men with hearing protection, the jet has a starting air injection line I presume in the intake throat AND perhaps three or four other injection points plus a thick black wire which looks like the ignition cable. One of the lines might be a sensor but it might be that they are injecting propane in at least 3 different locals in the combustion chamber. Seems such a set-up would make for a more sudden, intimate fuel/air charge. Just something some of you might like to try.
Mark
Does anyone know off-hand how many gallons an hour a Dynajet consumes in gasoline? I was trying to figure out how many gallons a spray nozzle would have to throw out for the Dynajet to produce it's ~4.5 or so pounds of thrust. How much does gasoline weigh? About 6 pounds? Simple math but I'm very tired/sleepy now. That way I could figure out just the right size PJ nozzle to match that much thrust. http://www.bete.com/products/pages/pj.htm
And again, as Pieter first brought this site to my attention, here are all the many choices. http://www.bete.com/products/byname.htm
They're rather interesting, so many variations.
Mark

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