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Post by azwood on Jun 10, 2018 23:31:28 GMT -5
Just pieceing together the jet pipe so i can read some egt,s what size pitot tube and what sort of gauge do i need for measuring presure i remember you guys saying it might make 70 to 100pounds of thrust so do i just use a gauge that reads up to say 200psi ?
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Post by racket on Jun 11, 2018 0:01:38 GMT -5
The pitot tube need only be 5 mm dia steel tube , I use brake line , and its gauge need only read up to 15 psi - 1 Bar , you'll only have ~6-10 psi of total pressure in the jetpipe at full power .
Position the pitot at least 100 mm downstream of the turb wheel , the further the better to allow the gases to "even out" before impacting the inlet to the pitot , have the inlet at ~20 -25 mm radially in from the wall so that its not influenced by either the boundary layer at the wall or the wheel hub , you want it in the main stream of gases exiting the wheel .
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Post by azwood on Jun 11, 2018 0:06:43 GMT -5
Ok thanks to easy ill find something to use tomorrow The pitot tube need only be 5 mm dia steel tube , I use brake line , and its gauge need only read up to 15 psi - 1 Bar , you'll only have ~6-10 psi of total pressure in the jetpipe at full power . Position the pitot at least 100 mm downstream of the turb wheel , the further the better to allow the gases to "even out" before impacting the inlet to the pitot , have the inlet at ~20 -25 mm radially in from the wall so that its not influenced by either the boundary layer at the wall or the wheel hub , you want it in the main stream of gases exiting the wheel .
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Post by azwood on Jun 11, 2018 17:48:11 GMT -5
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Post by racket on Jun 11, 2018 19:08:55 GMT -5
LOL...............love the LPG "ignition" ;-)
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Post by azwood on Jun 11, 2018 19:24:04 GMT -5
Lol yeah scared my neighbor LOL...............love the LPG "ignition" ;-)
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Post by azwood on Jun 12, 2018 1:53:04 GMT -5
Just wondering how do they normally start smaller jets without lpg it would be nice to work out something for down the track
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BFTO
Veteran Member
Joined: February 2016
Posts: 128
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Post by BFTO on Jun 12, 2018 4:01:25 GMT -5
Just wondering how do they normally start smaller jets without lpg it would be nice to work out something for down the track A small high pressure nozzle for start and a bigger nozzle for higher power settings, is one solution.
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Post by racket on Jun 12, 2018 4:12:39 GMT -5
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Post by azwood on Jun 12, 2018 4:16:34 GMT -5
Thats an interesting little gadget
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Post by racket on Jun 12, 2018 4:26:34 GMT -5
Yep , I purchased one a year or so ago but never got around to experimenting with it , I also sourced a couple of cruder/cheaper versions from India which I think were for tractors .
With a high energy ignition system as used on full sized engines a fine spray of kero will ignite , but for initial experiments with our engines the LPG pilot light gives certainty of ignition of whatever is fed into the engine .
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Post by azwood on Jun 12, 2018 4:29:55 GMT -5
I wondered if there's a way to make evap tubes that preheated electrically somehow like a glow plug Yep , I purchased one a year or so ago but never got around to experimenting with it , I also sourced a couple of cruder/cheaper versions from India which I think were for tractors . With a high energy ignition system as used on full sized engines a fine spray of kero will ignite , but for initial experiments with our engines the LPG pilot light gives certainty of ignition of whatever is fed into the engine .
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Post by racket on Jun 12, 2018 4:45:16 GMT -5
A lotta electrical power required to "boil off" a couple of litres per minute of fuel
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Post by Johansson on Jun 12, 2018 15:03:10 GMT -5
I used a Danfoss spray nozzle centrally placed on top of the combustor for idle running in one of my older turbocharger based turbines, it preheated the evaps into which a second fuel pump were feeding fuel through a throttle valve. Worked like a charm.
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Post by azwood on Jun 12, 2018 17:38:08 GMT -5
Ok Thank you it would be nice to only need one fuel and not have to use the lpg I used a Danfoss spray nozzle centrally placed on top of the combustor for idle running in one of my older turbocharger based turbines, it preheated the evaps into which a second fuel pump were feeding fuel through a throttle valve. Worked like a charm.
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