*rubs chin* more and more i look at the screw compressor idea of an engine. the more i want to step away from it, and go with a traditional turbine engines that have actual blades,  vs vanes / threads of a screw compressor.  but what gets me is the RPM's and small over all diameter of the fan blades.   the only way i could compensate, for lower RPM's and diameter. is to place more fan blades,  to increase overall length that the blades take up. the length really not the problem, but the "intake air" and "exhaust" is the problem, and more to the point using drive shafts to connect up to a generator and hyd pump.

 with a turbine engine, and all the crud that gets kicked up while in the field. not sure how i could run air intake,  and hook up to air filters on another section of the SSTT.  and in that routing air around the turbine engine fans and turbine itself,  or routing around generator and hyd pump.

if i stay with screw compressor engine setup.  i can create passage ways via using something like planetary gear setup, with sun gear, planetary gears, and ring gear.  and work air passages between the planet gears  ((gears in this case = screw compressor vanes))   if i tried same thing for fan blades. i would most likely get in trouble at lower RPM's and never be able to create enough pressure to ignite diesel fuel via pressure and heat.

i guess only difference going between fan blades and screw compressor (vanes),  is i am creating a more physical barrier, to help compress air. and not allow the air to backfeed back out the intake in a sense.    i guess that starting to make sense.   screw compressor vanes vs turbine engine fan blades. would be like changing blade style for say a centrifuge pump.  instead of high volume per time at low pressure, i would be changing for a medium volume per time for medium pressure.

*DUH* moment, maybe i can stay with a more traditional turbine engine setup.  its just that the blades, will be sucking in the center, and blowing at the tips.  arghs, still be at the mercy of lower RPM's, and not being able to create a higher compressed air pressure.

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alright, enough doubt, staying with screw compressors.

the next issue, is i need to look at 3D model better, to see if circumference of "planetary gears" (outer compression screws), needs to be adjusted to the "arc length", between the planetary gears (outer compression screws) on the central sun gear (middle compression screw).   there maybe a high "friction loss" of air traveling from one screw to next, as it gets compressed, resulting in less efficient setup.

i wonder if the vanes (teeth of a gear), can be shaped a tad better, to cause a "pressure barrier" errr i guess that is bad term, a extremely turbulent zone, right were vanes (teeth of gears), meet,  that might be used as an advantage to reduce air leakage at the vanes touching from one screw to the next. 

also is there a way to shape vanes so that, as the vanes go around, and almost touch the casing. can the vanes be shaped, to create an air foil or barrier of air right at the edges/tip of the vanes. so there is less leakage of air.

amount of physical full 360 rotations a single vane makes, to amount of air compression, is going to effect things i am sure.  more full 360 turns = less compression per rotation. and perhaps less overall leakage between vanes.   but i would imagine. there is a point of to many turns and efficiency curve of amount of air leakage, would almost flat line at some point.   and same would go for min amount of turns.    i guess turns is bad term, and "twists" might be better statement. of how many twists the vanes make.  

the longer the overall compression screws are, the more "twists" i could make, and less compression would happen per full 360 degrees rotation. which would most likely result in a higher efficiency setup. (within reason).

were 2 compressions screw vanes mesh up (teeth of gear mesh up), one side there will be almost a "suction side (negative pressure)" and the other side will be a "positive pressure side",   i will need to keep this in mind, when i place the compression screws together, of what vane overlaps the other vane on the other screw compressor.  so that vanes might actually "touch" like gears, and create a better "seal" to keep air from leaking by.

never really tried to figure out were to inject "oil" into the screw compressors, along with how much.    if i apply "centrifuge" style pumps. to the screw compression vanes. oil would end up at the very tip of the vanes. were the seal would end up being wanted.    the only problem i have with injecting oil, is trying to twist vanes so tight, that a given amount of hyd oil could get in, and (then not be able to compress like air),  and hyd oil would start to seize the screws up from rotating. and start causing a bunch of extra friction heat, as oil leaked passed the vane tips.   and in that, the lubrication oil, sealing oil, cooling oil (what ever you want to call it), alone may determine how much air can be compressed down to.

alright, is going with planetary gear setup a good idea?,  vs only going with 2 compression screws.....    to state difference, 3 planetary compression screws and most likely larger diameter sun compression screw.   vs 2 compression screws.   it is not the "gear ratio" that has me concerned but rather how much air can be compressed (volume per time) and to what pressure
--planetary = higher air leakage between vanes and casing,  ((more overall circumference of case))  vs 2 compression screws.
--planetary = more seals between vanes meshing together, and in that most likely more air leakage at meshing points.
--planetary = could create a physical longer path or shorter path,  vs over all length of screws. other words planetary setup changes amount of twists, and amount of compression over, over all length of screws.

so what else am i missing, and need to take into account for shaping and building the compression screws????

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i am missing....

if i go with planetary gear like setup for the screw compressors.   both planets and the sun, will need to be exactly the same except, the helix curve will need to go in opposite direction for the sun gear (compression screw), ya a little slow on that one.   with that stated it gives me fewer choices to pick from...

and to limit things even further.... in order to keep rotation going in correct direction. odd amount of screws = NO NO. or less there are 2 screws that do not touch / mesh together.



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sent a few emails off to some companies, in attempt to see if i can find some more information of engines already out there. see what happens.