G B Reid MIMechE, SIMarEST

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G B Reid MIMechE, SIMarEST last won the day on March 7

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About G B Reid MIMechE, SIMarEST

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    Male
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    Benfleet, England
  • Interests
    Mechanical engineering "generalist", experience in Design (industrial, mechanical, aerospace grade components), Rail, Underground, defence, process flow optimisation, Project Engineering and Mechanical Systems 3D CAD user (various) since 1992. Electrical design installation and verification.
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  1. calculating tipping point

    Its a simple moment equation to find the CoG/M (depending on preference)...then just ensure the Cog is within the footprint of the...well...foot. If you carry out the calcs for each extreme and then a couple between these extremes, you will get a footprint of utilisation, which is the area within which the foot must always fall. You need a lot more detail, materials for framework, mass, profile etc. I understand why you may want to provide this additional data, but assistance is somewhat restricted without. Good luck!
  2. gears

    Any high torque axial step-down that requires minimal vibration.
  3. velocity diagrams

    I am somewhat tempted to answer by stating "lines on a piece of paper"....but somehow I do not think that is the answer you would be hoping for. Please consider the question that you are actually seeking answer for and I shall try and assist.
  4. Quesn on shape of aerofoil

    I agree with Dr D....but that said, I seem to recall something (in the dim an distant past) about placing the highest Bernouli lift to the front of the wing in order to make the wing more stable by use of a tailplane stabilisor... In typing this I am having some memories return....there is also a MUCH LOWER stall speed (ie the airraft has to go much faster to prevent stall) due to the lack of laminar flow across the top surface and very low angles of attack....basically the bullnose at the front encourages laminar flow as the angle of attack rises, whereas the complete opposite is true of the sharper leading edge...ie turbulent flow is encouraged, resulting in reduced pressure drop (Bernoulli effect) and loss of stability and lift. Theoretically, this could be countered by a greater reliance on Newtonian (Reactive) lift, but that is inherently unstable (Turbulent) and difficult to control anyway, so not an ideal situation!
  5. about refrigeration system

    Your best bet is to start reading up on the "ideal Gas Law" and then on the enthalpy of vapourisation. A combination of the two should then give you a good understanding. To answer your specific question though, yes....there is normally a "pinched pipe" that restricts the flow (yes, normally it is that simple)...on some of the "better engineered" versions it is a (very) small bore pipe.
  6. Vehicle's effect over a speed bump

    We know F = ma and the mass of the vehicle, from this we can calculate the force from each set of wheels. from the speed of the vehicle, we can calculate the length of time the force is applied. (ie m/s and then width of hump) From the mass of the road hump and spring force keeping it in place, we can can calculate the acceleration of the hump and the time which it is accelerating and the rate, which can be back calculated to give the required figures. The velocity itself will be dependant on the time the vehicle is in contact (F=ma), the overall mass of the hump/spring effects and the amount of energy harvested (ie the retardation effect of the "generator"). The velocity of the vehicle will reduce the amount of time the Force is applied, so the aceleration would not be as high, but this would be balanced by a significantly greater (square law) newtonian effect pushing the hump downward at the point of wheel impact. I would suggest experimental determination rather than calculation as the suspension effect of the tyre and the suspension itself will skew any calculated results. Sounds very interesting - good luck! Your english in the question is excellent!
  7. petroleum field

    ...and sometimes, just plain static pressure!
  8. difference between a pipe and a tube?

    A pipe is designed to pass fluids through and a tube, non fluids (e.g. wiring, vacuum delivery pods etc)
  9. obtain k from k factor?

    What are the units of the K factor? I can't remember exactly, but I do seem to recall it being hte reciprocal of the R value. The units would confirm one way or the other.
  10. damping coefficient

    For any coefficient of damping, there are three possible scenarios....underdamped, over damped or optimal damping. this varied from item to item and - as Dr D stated - there is no standard....each is unique to the application and can be (roughly) calculated from the spring you want to damp.
  11. calculation of fasteners

    There is another way.... ...if you calculate the friction between the motor and its mount and "preload" the bolts to a specific torque such that the realised friction exceeds any force the motor is likely to experience in use, the "strength" of the bolds becomes secondary to the effect they have on the preloaded surfaces. If properly calculates and "balanced", the overall strength of the bolts often falls down the pecking order of failure modes. This is a very often misunderstood reason for appropriate torque settings on screws and bolts....if appropriate, the preload eliminates any movement or losening as a result of hte loading of the unit....if inappropriate, the surfaces can experience deformation or premature cracking...not to mention the risk of hte bolt shearing!
  12. SI and CI engines

    An interesting way to cut down congestion though......
  13. Flow rate, Pressure rise and Power calculations. Fluid Mechanics

    I would like to know hte background of this question prior to offer any assistance... ...whilst more than happy to help, it sounds a little too-much like a college/univeristy homework question!
  14. Need to know the industry use of the following.

    It could be a drive shaft with vibration-dampers on it....? Where id you source it...? Any additional info may help be more specific...
  15. temperature and mass flow rate of ICE exhaust gas

    I can't help directly...but if you know the mass of the fuel being burnt and its callorific value, it is but a simple calculation. This can be extrapolated for the number of cylinders and the rpm (okay...just testing rad s^-1) to give a likely figure.