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Post by aquaticharpy on Mar 25, 2020 16:20:49 GMT -5
My turbocharger has finally arrived and I'm ready to start building and ordering supplies. Shes got a 72mm inducer and 88mm exducer, I couldnt get my caliper down to measure the reducer but I'll go with what the internets said. I'll be posting questions and updates on this thread. upload photos onlineThanks John
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Post by aquaticharpy on Mar 25, 2020 17:22:26 GMT -5
Could someone link me to where I can do the calculations for a flametube and all the bits for as much reliable power as I can get on diesel. I need to.start ordering pipe
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Post by racket on Mar 25, 2020 17:51:02 GMT -5
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Post by aquaticharpy on Mar 25, 2020 17:58:57 GMT -5
I though jetspecs was a rough estimating program for inefficient propane jets?
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Post by racket on Mar 25, 2020 18:56:10 GMT -5
Yes , Jetspecs is a crude device , but unless you wish to do all the calculations yourself , use Jetspecs
Without both compressor and turbine maps for your particular turbo theres no way of knowing exactly what the "perfect" flametube would be .
Jetspecs will allow you to get the maximum output from your engine , maximum output is dependant on your turbine inlet temperature ( T I T ) along with the mass flow rate which is dependant on your turbo configuration , rpm , losses through the system etc etc etc .............Jetspecs recommends generous proportions which helps cover a lot of construction "sins" .
Your turbo's rpm and temperatures have upper limits which are NOT to be exceeded , your engine has a finite thrust capability , TIT of 1450 F - 787 C and comp tip speed of 1450 ft/sec for safety reason with a turbo of unknown age and heritage , a brand new turbo from a reputable manufacturer will naturally be capable of being pushed a bit harder , but the responsibilty is on you to keep your turbo from destroying itself and potentially killing you in the process.
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Post by aquaticharpy on Mar 25, 2020 20:24:51 GMT -5
Jetspecs will get the most power from my jet then, even if I'm running diesel? And jetspecs will do the same math that the links you provided tell me how to do?
I'll try it out
Thanks John
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Post by racket on Mar 25, 2020 20:35:37 GMT -5
Yep , diesel will give the same power as kero , alky , nitromethane , propane , petrol, used engine oil , etc etc etc ................. forget about trying to relate automotive IC engines with turbines , they're different beasts
As long as your turbine inlet temperature is the same maximum safe 1450 F when burning any of those fuels , your thrust/power output should be the same, we only burn ~25-30% of the air going through the engine the rest is used to cool the combustion gases so that the turbine wheel doesn't melt
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Post by aquaticharpy on Mar 25, 2020 21:00:27 GMT -5
1/4 3/8 and 5/8 are the example the link had. What is the recommended hole size? Also, is it better to be a tad bigger or smaller with the combustion chamber?
Thanks John
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Post by aquaticharpy on Mar 25, 2020 21:43:04 GMT -5
I found this for a flame tube.
Pipe 10086 Nominal Pipe Size in Inches: 6 Wall Thickness: 0.5 Pipe ID: 5.625 Weight per Foot: 32.74 Section Modulus: 13.711 Gallon Capacity per Linear Foot: 1.2909
Hopefully itll work, although being .004 inches too small, hopefully the thickness is ok?
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Post by racket on Mar 25, 2020 22:24:11 GMT -5
The flametube needs to be stainless steel , anything over 0.5mm - 0.020" wall thickness is OK , though ~1.0mm - 0.040" is a good thickness , as long as the diameter of the tube is roughly within a 1/4-3/8" of what Jetspecs recommends it'll be OK .
The outer can needs to be a pressure vessel so some care with choice of material required, but most commercial tubing should cope with our relatively low pressures .
As for FT holes/sizes , adjust diameters to provide 10 in each Zone
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Post by aquaticharpy on Mar 25, 2020 23:24:23 GMT -5
Apparently stainless steel tube is extremely expensive. Where do you reccomend looking for FT tubing? Where do people usually get it without paying over 200$?
Thanks John
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Post by racket on Mar 25, 2020 23:42:12 GMT -5
Just get a piece of SS sheet and roughly roll into a tube , thats all I ever do , never used tubing for my FTs , theres only a couple of psi pressure drop across the flametube and its full of holes so the tack welding of the seam need not be perfect .
A 72 mm inducer only needs a 125mm - 5" dia ID flametube ( 3 times inducer area ) , so a 16" wide strip of 1 mm stainless sheet the length of your flametube won't cost much.
Or look for 5" dia stainless exhaust pipe , used on heavy trucking , checkout a large exhaust shop
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Post by aquaticharpy on Mar 26, 2020 0:03:56 GMT -5
It seems stainless sheet metal is going to get you pretty far in the homemade jet engine world.. I might order a big sheet for some pulsejet builds later on.
Thanks John
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Post by aquaticharpy on Mar 26, 2020 9:24:22 GMT -5
Where can I find relatively cheap stainless sheet metal? Also, we need a different nozzle. I'm not paying 250USD for a nozzle.
Thanks John
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Post by aquaticharpy on Mar 26, 2020 11:27:11 GMT -5
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