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  • Users: lengould
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  1. lengould

    Airscraft Propulsion by Compressed Air

    I'm sure this is a long-sorted issue, but was just wondering about relative efficiency issues. What would be the relative power efficiency of using eg. 3 barg compressed air as propulsion? Assuming of course that a) The wieght of the compressor machinery would be a non-issue. b) A venturi...
  2. lengould

    Oil-free compressor piston/ring design

    I'm working on designing a piston / cylinder / ring assembly for a large (eg. up to 6" bore) medium-high-pressure (eg. 30 bar) compressor requirement. Anyone know of available technology capable of doing this (eg. rings). Alternatively, looking for someone capable of designing this. Payment...
  3. lengould

    Texas Blackouts

    Anybody have any detailed information? Just heard on CNN about rolling blackouts inititated by the grid manager covering 80% of state. 15 min intervals. Seems afully early in the year. Pechez les vaches.
  4. lengould

    Motor design software.

    I've been hunting around for any available electric motor design software (eg. winding calculations, slot and conductor sizes / pitches, torque, voltage) for low voltage motor use (eg. <600V). Since the application is private "hobby" type work I was hoping to find some shareware / freeware...
  5. lengould

    Insulating and lubricating oil

    Hi. I was hoping someone's already done this and could share. I have a new requirement for a combination lubricant and electrical cooling fluid, eg. low voltage (300 to 600V) generator in an enclosure with fairly complex shafts and gears. I've looked at eg. Shell's DIALA HFX transformer oil...
  6. lengould

    Magnetic Theory

    I have a question regarding magnetics which I can't find a definite answer for, hoped someone could help. The question is "If a static hoop of iron, eg. a horseshoe, is set near a rotating cylindrical permanent magnet which has north pole at one end and south at the other so that one end of the...
  7. lengould

    Generator design

    Can anyone help me with a formula? I need to calculate the force required to move the piston of a linear generator from one position to the other. Specs currently are: 9 kW output at 409 V peak (240 vrms), stator comprised of 188 x 2mm E punchings in a circle to form a cylinder 12 cm diameter...
  8. lengould

    Information on Thermal or Solar H2 / O2 separation.

    I'd always thought this process required impossible temperatures and the products were impossible to separate. Recently I noticed this company, SHEC Labs http://www.shec-labs.com/process.htm which claims to have a workable process operating at around 800 degC and producing useful outputs. A US...
  9. lengould

    I thought this article deserved a t

    I thought this article deserved a thread of it's own. http://www.energypulse.net/centers/article/article_display.cfm?a_id=498 Makes a good read.
  10. lengould

    Temp drop accross gas turbine.

    The prior thread and references on the PBMR reminded me of a question I have wondered about. Hoping someone may be interested enough to clear it up for me. The question is how does one determine what the expander exhaust temperature will be from a gas turbine expander such as the helium...
  11. lengould

    Inverting tiff image

    Plotting to .tiff with ACAD14, I can only get white lines on black background. Plotting to any other target works fine, only tiff. Any ideas? (I use white background / blcak lines on display. I thought of reversing that but couldn't find how.) To BeartheHairless - sympathize totally but am...
  12. lengould

    Jet drive design

    (I hope this belongs here, none in marine eng. forum appeared logical) I am in pre-design of a new jet-drive based on an engine which develops full output of 50 Kw (65 hp) at 14,000 rpm. Before going too far into details, can you say immediately if it is possible (eg for an engineering...
  13. lengould

    Bearing Loss Calculation

    Hi. I need help /confirmation converting bearing loss nmm into watts losses for a small generator. I must have an error somewhere in here, the losses are so large. Problem data: 2 bearings 24.6 cm dia. carrying 747 kg load at 2880 rpm, coeff. fr. .00150 give a frictional moment of 1351 n mm...
  14. lengould

    Alternator size v.s. rpm rule of thumb

    I've heard but lost track of a rule of thumb relating the ratio of stator size (?mass?) of an AC generator to the rpm of the rotor. Has anyone else come across this? If so, do you know if the rule relates only to iron or to windings etc total?

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