This is what I am wondering about. Lets suppose I build a 50 lb thrust pulse jet engine and I want it to have a pressure fuel system. What size fuel line does it need, what fuel psi and what size fuel orfice does it need?
There should be a better way than trial and guess.
fuel system
Moderator: Mike Everman
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racketmotorman
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Re: fuel system
Hi
3/16" or 1/4" metal tubing for the line , Bosch EFI fuel pump , >20 GPH 90 degree solid pattern fuel spray nozzle .
Cheers
John
3/16" or 1/4" metal tubing for the line , Bosch EFI fuel pump , >20 GPH 90 degree solid pattern fuel spray nozzle .
Cheers
John
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Rocket Man
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Re: fuel system
That is not very scientific racketmotorman. I am building a fuel system like the German V1. I have a 100 psi air tank, adjustable regulator, fuel tank, fuel line, fuel injection into the engine. Trial and error so far I only need 20 psi, 1/4" fuel line, .125 orfice with gasoline and a needle valve. Engine starts easy at 20% throttle then throttles up to full power with a little adjustment. Works great. It would be much easier to have some type of formula to calculate orfice and fuel pressure instead of spending 2 hours experementing. I think I can make my own formulas in the future for larger engines.
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racketmotorman
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Re: fuel system
Hi
What, me not be scientific ......cheeky bugger
) ..................those are what I used http://www.youtube.com/watch?v=uqMn0A2aUdo
Flow increases as the square root of pressure change , your 20psi and 0.125" oriface will flow the same as 100 psi and a 0.083" oriface , BUT , and its a very BIG BUT !!! if you 20 psi is the actual pressure drop across your oriface , are you taking into account the engines internal pressure , then you have to differentiate between static , dynamic and total pressures and how they'll affect the outcomes , I have even more difficult fueling to contend with on my turbines with 18 injection points http://www.youtube.com/watch?v=NR0rsTbkOS4 ....................as I said ....cheeky bugger .
Cheers
John
What, me not be scientific ......cheeky bugger
) ..................those are what I used http://www.youtube.com/watch?v=uqMn0A2aUdo Flow increases as the square root of pressure change , your 20psi and 0.125" oriface will flow the same as 100 psi and a 0.083" oriface , BUT , and its a very BIG BUT !!! if you 20 psi is the actual pressure drop across your oriface , are you taking into account the engines internal pressure , then you have to differentiate between static , dynamic and total pressures and how they'll affect the outcomes , I have even more difficult fueling to contend with on my turbines with 18 injection points http://www.youtube.com/watch?v=NR0rsTbkOS4 ....................as I said ....cheeky bugger .
Cheers
John